Skip to main content
PLOS One logoLink to PLOS One
. 2026 Sep 25;21(9):e0358944. doi: 10.1371/journal.pone.0358944

The impact of adverse childhood experiences on the development of multimorbidity in older adults in Nigeria

Abdulsalam Ahmed 1, Hafiz T A Khan 2,3, Nestor Asiamah 4,*
Editor: Mithun Sikdar5
PMCID: PMC13614559  PMID: 42789523

Abstract

Background

Adverse Childhood Experiences (ACEs) are established life-course determinants of adult health, yet evidence linking ACEs to multimorbidity in sub-Saharan Africa remains limited. Nigeria is undergoing rapid demographic and epidemiological transitions characterized by population ageing and a rising burden of non-communicable diseases (NCDs). This study examined whether cumulative ACE exposure predicts multimorbidity among older adults in North-Central Nigeria.

Methods

A cross-sectional study was conducted among 734 adults aged ≥60 years in Niger State, Nigeria. ACE exposure before age 18 was assessed using the Adverse Childhood Experiences International Questionnaire (ACE-IQ) across 13 domains. Multimorbidity was defined as the presence of two or more chronic conditions (NICE criteria) from a list of 24 conditions and analyzed both as a count and dichotomized (≥3 vs. < 3 conditions). Descriptive statistics summarized participant characteristics. Chi-square tests examined bivariate associations. Hierarchical logistic regression models estimated adjusted odds ratios (ORs) and 95% confidence intervals (CIs) to determine independent predictors of multimorbidity.

Results

High cumulative ACE exposure was observed, with 68.4% reporting ≥4 ACEs. Multimorbidity was common: 38.4% reported three or more chronic conditions. ACE exposure was strongly associated with multimorbidity (χ² = 116.07, p < 0.001). In unadjusted analysis, participants reporting ≥4 ACEs had significantly higher odds of multimorbidity (OR = 67.14; 95% CI: 9.25–487.04). After adjusting for socio-demographic covariates, cumulative ACE exposure remained an independent predictor (OR = 15.58; 95% CI: 1.33–182.21). Advanced age (≥80 years) and living in three-generation households were also independently associated with multimorbidity.

Conclusions

Cumulative childhood adversity significantly predicts multimorbidity among older Nigerian adults, demonstrating a clear dose–response relationship. These findings underscore the importance of life-course approaches and trauma-informed strategies in public health policy. Early identification and prevention of childhood adversity may contribute to reducing the long-term burden of multimorbidity in low- and middle-income settings.

Background

Adverse Childhood Experiences (ACEs) are increasingly recognized as critical early-life determinants of health across the life course. ACEs refer to potentially traumatic events occurring before the age of 18 years that threaten a child’s physical or psychological well-being. These include child maltreatment (physical, emotional, or sexual abuse) and household dysfunction such as exposure to domestic violence, parental separation, substance misuse, mental illness, or incarceration within the household [1]. Since the landmark ACE Study, evidence has consistently demonstrated a graded relationship between cumulative childhood adversity and adverse health outcomes in adulthood [2]. Recent systematic reviews have reinforced this, showing that individuals with multiple ACEs are at significantly higher risk of chronic diseases in later life [3].

A substantial body of epidemiological research shows that individuals exposed to ACEs are at increased risk of chronic diseases, including hypertension, diabetes mellitus, cardiovascular diseases, and depression [2,3]. ACE exposure is also associated with higher likelihood of engaging in health-risk behaviors—such as tobacco use, harmful alcohol consumption, physical inactivity, and risky sexual behavior—which further elevate the risk of non-communicable diseases (NCDs) and premature mortality [3,5]. Importantly, ACEs frequently co-occur; exposure to one adverse event increases the likelihood of exposure to others, leading to cumulative biological and psychosocial stress [3,4]. Neurobiological evidence suggests that early-life toxic stress can result in long-term dysregulation of neuroendocrine, immune, and metabolic systems, thereby increasing vulnerability to chronic disease across the lifespan [5].

These long-term consequences are particularly relevant within the framework of multimorbidity, defined as the coexistence of two or more chronic conditions in an individual [6]. Globally, multimorbidity has emerged as a major public health challenge driven by population aging and epidemiological transition [6]. It is associated with increased healthcare utilization, reduced quality of life, polypharmacy, functional decline, and higher mortality [7]. Clinical management is complex because healthcare systems remain largely structured around single-disease models, and applying disease-specific guidelines to individuals with multiple conditions often results in treatment burden and fragmented care [8].

Understanding multimorbidity requires a life-course perspective that goes beyond single-disease etiology. Evidence suggests that the accumulation of chronic conditions is shaped by genetic predisposition, environmental exposures, behavioral risk factors, and social determinants of health [9]. From a public health standpoint, identifying early-life modifiable risk factors is crucial for prevention. Risk factors for NCDs accumulate across the lifespan, and early intervention during critical developmental windows may delay or compress the onset of chronic diseases in later life [10]. ACEs represent one such early-life exposure that may contribute to disease accumulation and multimorbidity in adulthood [3,4].

In low- and middle-income countries (LMICs), including Nigeria, the relevance of this life-course approach is particularly pronounced. Nigeria is undergoing demographic and epidemiological transitions characterized by a growing population of older adults and a rising burden of NCDs(11). NCDs account for approximately one-third of adult mortality in Nigeria, with cardiovascular diseases and diabetes among the leading contributors [11]. As survival improves and life expectancy increases, the prevalence of multimorbidity is also rising. However, the healthcare system remains largely oriented toward acute and single-disease management, with limited geriatric specialization and insufficient integration of preventive life-course strategies.

Despite evidence that childhood adversity is prevalent in many LMIC contexts, including poverty, exposure to violence, family instability, and limited social protection, there is limited empirical research examining the contribution of ACEs to multimorbidity among older adults in Nigeria. Most existing evidence on ACEs and chronic disease originates from high-income settings, limiting contextual applicability to African populations [3,4].

Previous studies have consistently shown that cumulative exposure to adverse childhood experiences (ACEs) is associated with an increased risk of chronic disease and multimorbidity in later life [2–4]. Evidence indicates a dose–response relationship, where individuals with a higher number of ACEs are more likely to develop multiple chronic conditions compared with those with few or no ACEs. These associations persist even after accounting for sociodemographic factors such as age, gender, education, and family structure. Earlier research underscores that ACEs contribute to multimorbidity through both behavioral and biological pathways, highlighting the importance of life-course approaches and early preventive strategies to mitigate long-term health risks [2–4]. Identifying ACEs as an upstream determinant of multimorbidity has important implications for policy, prevention, and clinical care. Early interventions targeting children at risk of adversity may reduce the future burden of chronic disease and multimorbidity, particularly in LMICs where healthcare systems face resource constraints [3,4,9].

Biological and neurodevelopmental evidence provides plausible mechanisms linking adverse childhood experiences (ACEs) to later-life health outcomes. Research indicates that early adversity can induce lasting alterations in brain structure and function, with consequences for physical and mental health across the lifespan [12]. These neurobiological disruptions may persist into adulthood, increasing vulnerability to chronic disease development and progression [12]. Although the ACE framework has been widely used to retrospectively assess childhood adversity and its long-term health effects [13], comparatively less attention has been paid to broader measures of mental health, well-being, and modifiable life-course risk factors. Importantly, early life represents a critical window for preventive intervention [2].

Against the backdrop of a rapidly ageing population and rising multimorbidity in Nigeria and globally, health systems, often constrained by limited geriatric expertise, face increasing challenges [14]. Identifying modifiable early-life determinants such as ACEs may therefore inform prevention strategies aimed at delaying or compressing multimorbidity. Extending previous research, this study examined whether cumulative ACE exposure predicts multimorbidity, assessing the graded (dose–response) relationship between ACE burden and multimorbidity among older adults with established chronic conditions. By doing so, it contributes to the growing evidence base on the long-term health consequences of childhood adversity in north-central Nigeria.

Methods

Study design and ethical approval

A minimum sample size of 800 was calculated using the standard formula for large populations (N > 10,000) with a 5% margin of error. Based on hospital records, approximately 105,000 patients aged ≥60 years constituted the sampling frame. The initial sample size estimate was ~ 400, which was doubled to 800 to improve precision and account for potential non-response. A purposive selection was used to identify four high-volume public secondary hospitals (Bida, Kontagora, Minna, and Suleja) across Niger State. The study adopted a cross-sectional design targeting older adults (≥60 years) with multimorbidity (≥2 chronic conditions) attending outpatient clinics. Systematic random sampling was used to recruit eligible participants during routine clinic attendance. Data were collected from October 2021 to February 2022 using a structured, pre-tested questionnaire administered via face-to-face interviews. The instrument was deployed through the JISC online platform (University of West London). Participants were eligible if they were aged ≥60 years, had multimorbidity, attended selected outpatient departments during the study period, and could provide informed responses. Written informed consent was obtained from all participants. Data confidentiality was maintained, and participants retained the right to withdraw at any time. Interviews were conducted in English or Hausa according to participant preference. This clinic-based geriatric study was conducted as part of a larger investigation, with detailed methodology reported in previous publications [15–17].

Ethical approval was obtained from the College of Nursing, Midwifery, and Healthcare Research Ethics Panel, University of West London (Approval No. 1055), and authorization to collect data was granted by the Research, Ethics, and Publication Committee (REPC) of the Hospitals Management Board, Minna, Niger State, Nigeria. Written informed consent was obtained from all participants before partaking.

Measurement of variables

Socio-demographic characteristics.

Participant demographics collected included age, sex, ethnicity, marital status, family structure, education level, occupation, and monthly household income. Age was treated as a continuous variable and later grouped into 10-year intervals. Marital status was classified as never married, currently married, divorced, separated, or widowed. Education level was categorized from illiterate to postgraduate. Occupation was classified as government employee, business owner, family business worker, company staff/worker, dependent, retired, or other. Family structure was grouped as nuclear, three-generation, or extended family.

Adverse childhood experiences (ACEs).

ACE exposure was measured using the Adverse Childhood Experiences International Questionnaire (ACE-IQ), a validated instrument widely used in large-scale studies of childhood adversity. Participants reported experiences before age 18 across 13 domains: physical abuse, emotional abuse, sexual abuse, household alcohol or drug abuse, incarcerated household member, living with someone chronically depressed, mentally ill, institutionalized, or suicidal, household violence, parental separation/divorce, emotional neglect, physical neglect, bullying, community violence, and collective violence. Responses were dichotomized (yes = 1, no = 0), summed to generate a cumulative ACE score (0–13), and categorized into five groups: 0, 1, 2, 3, and ≥4.

Multimorbidity.

Multimorbidity was defined according to NICE guidelines as the presence of two or more chronic conditions. A total of 24 conditions were assessed, including hypertension, diabetes, peptic ulcer, arthritis, heart failure, stroke, angina, COPD, chronic liver disease, obesity, depression, asthma, cataract, chronic renal failure, osteoporosis, glaucoma, tuberculosis, cancer, Alzheimer’s disease, dementia, and other mental or emotional illnesses. Self-reported diagnoses were cross-checked against medical records when available. Multimorbidity was analyzed both as a simple count of chronic conditions and categorized as 2, 3, 4, or ≥5 conditions.

Confounding factors.

Potential confounders included age, sex, marital status, education, occupation, family structure, ethnicity, and income. These variables were included in multivariable analyses to adjust for their potential influence on multimorbidity.

Statistical analysis

Data were collated, coded, and entered using the JISC online platform, then exported to IBM SPSS version 27. Descriptive statistics summarized participant characteristics, ACE exposure, and multimorbidity status. Categorical variables were expressed as frequencies and percentages.

Bivariate associations between multimorbidity and selected variables were assessed using Chi-square (χ²) tests, with Fisher’s exact test applied where expected counts were <5. Variables examined included age, gender, marital status, family structure, education, occupation, income, ethnicity, and ACE score. Statistical significance was set at p < 0.05.

Hierarchical logistic regression was conducted to identify independent predictors of multimorbidity (≥3 chronic conditions). Two models were constructed:

  • Model 1 included only ACE variables to examine unadjusted associations.

  • Model 2 included ACEs and socio-demographic covariates (age, sex, marital status, education, occupation, income, family structure, and ethnicity) to adjust for confounding.

ACE scores were treated as categorical variables (0, 1, 2, 3, ≥ 4). Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated. Model fit was evaluated using the Hosmer–Lemeshow goodness-of-fit test, and multicollinearity was assessed using variance inflation factors (VIFs), with VIF < 5 considered acceptable.

Model adequacy was assessed using the Hosmer–Lemeshow goodness-of-fit test, while multicollinearity among independent variables was evaluated using Variance Inflation Factors (VIFs). All VIF values were within acceptable limits, indicating no evidence of significant collinearity.

Results

Participant characteristics

A total of 800 older adults were initially recruited for this study. Of these, 734 (91.75%) completed all required study procedures and were included in the final analysis. The majority were female (59.1%) and aged 60–69 years (72.1%). Most were currently married (65.8%) and lived in extended families (60.4%). Regarding education, 62.9% were illiterate, and only 2.2% had postgraduate qualifications. Common occupations included business ownership (38.1%) and dependence on family support (29.2%). Participants were predominantly of Nupe (27.8%) and Gwarri (26.3%) ethnicity. Household income was generally low, with 65% earning ≤15,000 Naira monthly. High cumulative ACE exposure was reported, with 68.4% experiencing four or more ACEs. Multimorbidity was common, with 38.4% reporting three or more chronic conditions (Tables 1, 2 and 3).

Table 1. Socio-demographic characteristics of study participants (N = 734).

Variables n %
Gender 1
 Male 300 40.9
 Female 434 59.1
Age
 60-64 267 35.7
 65-69 123 36.4
 70-74 262 16.8
 75-79 29 4.0
 80 and greater 53 7.2
Marital status
 Never married 11 1.5
 Currently married 483 65.8
 Divorced 21 2.9
 Separated 19 2.6
 Widow/er 200 27.2
Family structure
 Nuclear Family 140 19.1
 Three Generation Family 150 20.5
 Extended Family 442 60.4
Education level
 Illiterate 462 62.9
 Can read and write 35 4.8
 Primary school level 74 10.1
 secondary school 64 8.7
 Tertiary school 83 11.3
 Post-graduate 16 2.2
Occupation
 Government staff 36 4.9
 Own business 280 38.1
 Involve in the family business 36 4.9
 Company staff/ worker 30 4.1
 Dependent 214 29.2
 Retired 128 17.4
 Others (specify) 10 1.4
Ethnicity
 Gwarri 193 26.3
 Hausa 174 23.7
 Nupe 204 27.8
 Others 163 22.2
Level of income (Naira)
 0-15k 477 65.0
 16k-30k 124 16.9
 31k-45k 30 4.1
 46k-60k 27 3.7
 greater than 60 76 10.4

Table 2. Frequency and percentage distribution of ACE exposure and multimorbidity.

ACE/Multimorbidity Cases (n) %
ACE
0 6 0.8
1 44 6.0
2 65 8.7
3 117 15.9
4+ 502 68.4
Multimorbidity
2 452 61.6
3 230 31.3
4 38 5.2
5+ 14 1.9

Table 3. Bivariate associations between multimorbidity and selected independent variables.

Variables <3 diseases

n (%)
3 + diseases

n (%)




P value
ACE 116.07 <.001
 0 71 (13.7) 1 (0.4) 4df
 1 31 (6.0) 13 (4.6)
 2 53 (10.2) 12 (4.3)
 3 105 (20.3) 12 (4.3)
 4+ 256 (49.8) 244 (86.5)
Age
 60-64 184 (40.7) 78 (27.7) 47.56 <.001
 65-69 178 (39.4) 89 (31.6) 4df
 70-74 62 (13.7) 61 (21.6)
 75-79 14 (3.1) 15 (5.3)
 80+ 14 (3.1) 39 (13.8)
Gender 4.18 .041
 Male 198 (43.8) 102 (36.2) 1df
 Female 254 (56.2) 180 (63.8)
Marital status 29.82 <.001
 Never married 5 (1.1) 6 (2.1) 4df
 Currently married 330 (73.0) 153 (54.3)
 Divorced 13 (2.9) 8 (2.8)
 Separated 11 (2.4) 8 (2.8)
 Widowed 93 (20.6) 107 (37.9)
Occupation 79.93 <.001
 Government staff 30 (6.6) 6 (2.1) 6df
 Own business 191 (42.3) 90 (31.9)
 Involve in the family business 24 (5.3) 12 (4.3)
 Company staff/worker 26 (5.8) 4 (1.4)
 Dependent 81 (17.9) 133 (47.2)
 Retired 92 (20.4) 36 (12.8)
 Others 8 (1.8) 1 (0.4)
Education 36.56 <.001
 Illiterate 248 (54.9) 214 (75.9) 5df
 Can read and write 25 (5.5) 10 (3.5)
 Primary school level 54 (11.9) 20 (7.1)
 Secondary school level 45 (10.0) 19 (6.7)
 Tertiary school 65 (14.4) 18 (6.4)
 Post-graduate 15 (3.3) 1 (0.4)
Income 18.92 <.001
 0-15K 269 (59.5) 208 (73.8) 4df
 16-30k 86 (19) 38 (13.5)
 31-45k 18 (4.0) 12 (4.3)
 46-60k 22 (4.9) 5 (1.8)
 >60k 57 (12.6) 19 (6.7)
Family structure 35.80 <.001
 Nuclear family 108 (23.9) 33 (11.7) 2df
 Three generation family 65 (14.4) 86 (30.5)
 Extended family 279 (61.7) 163 (57.8)
Ethnicity 3.72 .293
 Gwarri 115 (25.4) 78 (27.7) 3df
 Hausa 103 (22.8) 71 (25.2)
 Nupe 137 (30.3) 67 (23.8)
 Others 97 (21.5) 66 (23.4)

Adverse childhood experiences and multimorbidity

The distribution of adverse childhood experiences (ACEs) and multimorbidity is presented in Table 2 and illustrated in Fig 1. A high proportion of participants reported substantial exposure to childhood adversity, with 68.4% experiencing four or more ACEs before the age of 18. Smaller proportions reported three (15.9%), two (8.7%), one (6.0%), or no ACE exposure (0.8%).

Fig 1. Percent (%) distribution of various types of ACE in the study sample.

Fig 1

Regarding multimorbidity, most participants (61.6%) reported having two chronic conditions, while 31.3% had three conditions. A smaller percentage reported four (5.2%) or five or more (1.9%) chronic conditions.

Overall, both cumulative ACE exposure and the burden of multiple chronic conditions were considerable in this study population (Table 2; Fig 1).

Bivariate associations with multimorbidity

Bivariate analyses revealed significant associations between multimorbidity and ACE exposure, age, gender, marital status, education, occupation, income, and family structure (p < 0.05). Participants with higher cumulative ACE scores were more likely to report three or more chronic conditions (χ² = 116.07, df = 4, p < 0.001). Advanced age (≥80 years) was associated with higher multimorbidity prevalence (χ² = 47.56, df = 4, p < 0.001). Female participants had slightly higher multimorbidity rates than males (χ² = 4.18, df = 1, p = 0.041). Ethnicity was not significantly associated with multimorbidity (χ² = 3.72, df = 3, p = 0.293) (Table 3).

Independent predictors of multimorbidity

As shown in Table 4, hierarchical logistic regression demonstrated that cumulative adverse childhood experience (ACE) exposure was a strong independent predictor of multimorbidity. In the unadjusted model (Model 1), participants reporting ≥4 ACEs had substantially higher odds of multimorbidity compared with those with no ACE exposure (OR = 67.14, 95% CI: 9.25–487.04, p = 0.001). After adjustment for socio-demographic variables (Model 2), the association remained statistically significant, although attenuated (OR = 15.58, 95% CI: 1.33–182.21, p = 0.029).

Table 4. Multivariable logistic regression analysis of factors associated with multimorbidity.

Variable Odds ratio P value 95%CI Odd ratio P value 95%CI
Lower Upper Lower Upper
ACE
0 1.00 1.00
1 29.77 .001 3.73 237.67 8.08 .108 .63 103.37
2 16.07 .009 2.02 127.49 3.45 .338 .27 43.42
3 8.11 .047 1.03 63.79 1.66 .693 .13 20.52
4+ 67.14 .001 9.25 487.04 15.58 .029 1.33 182.21
Age
60-64 1.00
65-69 .88 .556 .57 1.34
70-74 1.11 .694 .63 1.95
75-79 1.38 .492 .54 3.48
80+ 2.98

.009 1.31 6.75
Gender
Male 1.00
Female

.93 .726 .62

1.39
Marital status
Never married 1.00
Currently married .99 .992 .26 3.74
Divorced .84 .845 .16 4.43
Separated .68 .662 .12 3.68
Widowed

.85 .827 .21 3.39
Occupation
Government staff 1.00
Own business .93 .921 .26 3.27
Involve in family business .88 .871 .21 3.67
Company staff/worker .30 .157 .05 1.59
Dependent 2.82 .122 .75 10.52
Retired 1.52 .474 .47 4.86
Others .27 .298

.02

3.16
Education
Illiterate 1.00
Can read and write .61 .267 .26 1.44
Primary school level .63 .179 .33 1.22
Secondary school level .90 .816 .37 2.16
Tertiary school .30 .050 .09 .99
Post-graduate .08

.045 .01 .94
Income
0-15K 1.00
16-30k .90 .712 .53 1.53
31-45k 2.00 .162 .75 5.30
46-60k .82 .774 .21 3.12
>60k 2.54 .093 .85 7.58
Family structure
Nuclear family 1.00
Three generation family 2.15 .015 1.16 4.00
Extended family 1.46 .142 .88 2.42
Ethnicity
Gwarri 1.00
Hausa .86 .539 .53 1.39
Nupe .95 .847 .58 1.54
Others .76 .299 .46 1.26

Among covariates, advanced age (≥80 years) was independently associated with multimorbidity (OR = 2.98, 95% CI: 1.31–6.75, p = 0.009), as was living in a three-generation household (OR = 2.15, 95% CI: 1.16–4.00, p = 0.015). Higher educational attainment showed an inverse association with multimorbidity. Other factors, including sex, marital status, occupation, income, and ethnicity, were not statistically significant after adjustment. Model diagnostics confirmed adequate goodness-of-fit and no evidence of multicollinearity among covariates.

Overall, the findings indicate that cumulative ACE exposure, alongside advanced age and household structure, are important determinants of multimorbidity in older adults in Nigeria. The magnitude of the ACE effect should be interpreted cautiously given the wide confidence intervals observed, likely reflecting sparse data in some exposure categories and variability in responses, which limits estimate precision.

Discussion

This study provides novel evidence on the relationship between adverse childhood experiences (ACEs) and multimorbidity among older adults in Niger State, North-Central Nigeria. To our knowledge, it represents one of the first empirical investigations in this setting to examine the long-term implications of cumulative childhood adversity for health in later life. The findings demonstrate a high prevalence of ACE exposure within this cohort and show that cumulative ACEs significantly predict multimorbidity among older adults [18].

The distribution of ACEs observed in this study aligns with global evidence indicating that childhood adversity is widespread across diverse populations. International research consistently demonstrates that ACE exposure cuts across racial and ethnic groups, although the magnitude varies by socioeconomic context [18]. Importantly, earlier studies have shown that exposure to one ACE increases the likelihood of additional adversities, reflecting a clustering pattern that may intensify cumulative risk. This clustering effect strengthens the predictive value of cumulative ACE scores for adverse health outcomes in adulthood [19].

Emotional neglect and exposure to community violence were the most frequently reported ACE domains in this study. Participants with these experiences were more likely to report higher numbers of chronic conditions, suggesting that these specific adversities may be important predictors of later-life multimorbidity [19]. These findings are consistent with previous studies demonstrating that psychosocial stressors during childhood significantly predict chronic disease risk in adulthood [20]. However, variations in the most prevalent ACE domains compared with other Nigerian studies likely reflect regional and sociocultural differences in exposure patterns and reporting practices [21].

The high prevalence of ACEs reported in this cohort must be interpreted cautiously. Although participants were provided sufficient time to recall pre-18 experiences, retrospective reporting may still be influenced by recall bias, particularly among older age groups. Furthermore, because the sample comprised individuals with chronic conditions, the observed distribution of multimorbidity may not fully represent that of the broader population. Educational level may also shape how individuals interpret and report childhood adversity, potentially influencing prevalence estimates [24].

While identifying determinants of ACE exposure was not a primary objective of this study, prior Nigerian research suggests that lower maternal education and lower household wealth significantly predict childhood adversity [20]. The predominance of low educational attainment and low income among participants in this study may therefore reflect structural vulnerabilities that increase exposure to ACEs and, in turn, predict poorer health trajectories. These findings suggest a possible intergenerational cycle in which socioeconomic disadvantage increases the likelihood of ACE exposure, which subsequently predicts chronic disease accumulation in later life [20].

The primary objective of this analysis was to evaluate whether childhood adversity predicts multimorbidity among older Nigerian adults. The findings demonstrate a statistically significant moderate positive correlation between cumulative ACE scores and the number of chronic conditions (r = 0.362, p = 0.01). Hierarchical logistic regression further confirmed that cumulative ACE exposure independently predicts multimorbidity. A clear dose–response pattern was observed: individuals reporting four or more ACEs had substantially higher odds of multimorbidity compared with those reporting none, even after adjustment for socio-demographic covariates. Although adjustment reduced the magnitude of the association, cumulative ACE exposure remained a significant independent predictor of multimorbidity [2,22].

These results are consistent with international evidence showing that cumulative ACE exposure predicts multimorbidity, functional decline, and premature mortality in adulthood [2,22]. The observed dose-dependent relationship supports life-course epidemiological models, which posit that early-life adversity exerts long-term biological and behavioral effects that shape disease risk across the lifespan. Chronic stress activation, maladaptive coping behaviors, and socioeconomic disadvantage may act as mediating pathways through which ACEs predict chronic disease clustering in later life [23,24].

Overall, the findings indicate that cumulative childhood adversity significantly predicts multimorbidity among older adults in Nigeria. Integrating ACE screening and trauma-informed approaches into public health policy may enhance early identification of high-risk populations and strengthen chronic disease prevention strategies [2,22]. A life-course approach that prioritizes early intervention may therefore play a critical role in reducing the long-term burden of multimorbidity in low- and middle-income settings [23,24].

Limitations

This study’s cross-sectional design limits causal inference between adverse childhood experiences (ACEs) and multimorbidity. Retrospective self-reported ACEs are subject to recall bias and may result in both differential and non-differential misclassification. Recall may be influenced by current health status, leading to over-reporting, or by memory decay and social desirability, leading to under-reporting; both could bias effect estimates in either direction. Although chronic conditions were cross-checked where possible using clinical records, some misclassification may persist.

The study was conducted in North-Central Nigeria, which may limit generalizability. In addition, residual confounding from unmeasured factors such as lifestyle and environmental exposures cannot be excluded.

Conclusion

Cumulative adverse childhood experiences significantly predict multimorbidity among older Nigerian adults. These findings underscore the importance of early-life interventions and life-course approaches. Integrating ACE screening and trauma-informed strategies into healthcare and public health policy may improve early identification of high-risk individuals and inform strategies to prevent chronic disease accumulation.

Supporting information

S1 Data. Quantitative data.

(XLS)

pone.0358944.s001.xls (703KB, xls)

Data Availability

The data used for this study is attached as supplementary information. The name of the data file is “Data”.

Funding Statement

The author(s) received no specific funding for this work.

References

  • 1.Felitti VJ. Adverse childhood experiences and adult health. Acad Pediatr. 2009;9(3):131–2. doi: 10.1016/j.acap.2009.03.001 [DOI] [PubMed] [Google Scholar]
  • 2.Hughes K, Bellis MA, Hardcastle KA, Sethi D, Butchart A, Mikton C, et al. The effect of multiple adverse childhood experiences on health: a systematic review and meta-analysis. Lancet Public Health. 2017;2(8):e356–66. doi: 10.1016/S2468-2667(17)30118-4 [DOI] [PubMed] [Google Scholar]
  • 3.Senaratne DNS, Thakkar B, Smith BH, Hales TG, Marryat L, Colvin LA. The impact of adverse childhood experiences on multimorbidity: a systematic review and meta-analysis. BMC Med. 2024;22(1):315. doi: 10.1186/s12916-024-03505-w [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 4.Taylor K, Demakakos P. Adverse childhood experiences and trajectories of multimorbidity in individuals aged over 50: Evidence from the English Longitudinal Study of Ageing. Child Abuse Negl. 2024;149:106653. doi: 10.1016/j.chiabu.2024.106653 [DOI] [PubMed] [Google Scholar]
  • 5.Shonkoff JP, Garner AS. Committee on psychosocial aspects of child and family health committee on early childhood, adoption, and dependent care section on developmental and behavioral pediatrics the lifelong effects of early childhood adversity and toxic stress. Pediatrics. 2012;129(1):e232–46. [DOI] [PubMed] [Google Scholar]
  • 6.Marengoni A, Angleman S, Melis R, Mangialasche F, Karp A, Garmen A, et al. Aging with multimorbidity: a systematic review of the literature. Ageing Res Rev. 2011;10(4):430–9. doi: 10.1016/j.arr.2011.03.003 [DOI] [PubMed] [Google Scholar]
  • 7.Boyd CM, Darer J, Boult C, Fried LP, Boult L, Wu AW. Clinical practice guidelines and quality of care for older patients with multiple comorbid diseases: implications for pay for performance. JAMA. 2005;294(6):716–24. doi: 10.1001/jama.294.6.716 [DOI] [PubMed] [Google Scholar]
  • 8.Organization WH. Global action plan for the prevention and control of noncommunicable diseases 2013-2020. World Health Organization; 2013. [Google Scholar]
  • 9.Odunyemi A, Islam MT, Alam K. The financial burden of noncommunicable diseases from out-of-pocket expenditure in sub-Saharan Africa: a scoping review. Health Promot Int. 2024;39(5):daae114. doi: 10.1093/heapro/daae114 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 10.Gouda HN, Charlson F, Sorsdahl K, Ahmadzada S, Ferrari AJ, Erskine H, et al. Burden of non-communicable diseases in sub-Saharan Africa, 1990–2017: results from the Global Burden of Disease Study 2017. Lancet Glob Heal. 2019;7(10):e1375–87. [DOI] [PubMed] [Google Scholar]
  • 11.Demographic N. National population commission (NPC)[Nigeria] and ICF International. Nigeria: Abuja, Nigeria, and Rockville, (MD): NPC and ICF International; 2019. [Google Scholar]
  • 12.Teicher MH, Samson JA. Annual Research Review: Enduring neurobiological effects of childhood abuse and neglect. J Child Psychol Psychiatry. 2016;57(3):241–66. doi: 10.1111/jcpp.12507 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 13.Felitti VJ, Anda RF, Nordenberg D, Williamson DF, Spitz AM, Edwards V, et al. Relationship of childhood abuse and household dysfunction to many of the leading causes of death in adults. The Adverse Childhood Experiences (ACE) Study. Am J Prev Med. 1998;14(4):245–58. doi: 10.1016/s0749-3797(98)00017-8 [DOI] [PubMed] [Google Scholar]
  • 14.Beard JR, Officer A, de Carvalho IA, Sadana R, Pot AM, Michel J-P, et al. The World report on ageing and health: a policy framework for healthy ageing. Lancet. 2016;387(10033):2145–54. doi: 10.1016/S0140-6736(15)00516-4 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 15.Ahmed A, Khan HTA, Lawal M. The Prevalence, Pattern, and Burden of Multimorbidity Among Older Adults in Niger State, Northern Nigeria. Illness Crisis Loss. 2024;33(3):684–701. doi: 10.1177/10541373241268305 [DOI] [Google Scholar]
  • 16.Ahmed A, Khan HTA, Lawal M. Patients’ Satisfaction with Healthcare Services Among Older People with Multimorbidity: Subnational Gender Perspective. Popul Ageing. 2024;18(1):119–32. doi: 10.1007/s12062-024-09455-8 [DOI] [Google Scholar]
  • 17.Ahmed A, Khan HTA, Lawal M. Effective hospital care delivery model for older people in Nigeria with multimorbidity: recommendations for practice. In: Healthcare. MDPI; 2022. 1268 p. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 18.Bethell CD, Davis MB, Gombojav N, Stumbo S, Powers K. Issue brief: Adverse childhood experiences among US children. Child Adolesc Heal Meas Initiat Johns Hopkins Bloom Sch Public Heal. 2017. [Google Scholar]
  • 19.Vásquez E, Quiñones A, Ramirez S, Udo T. Association Between Adverse Childhood Events and Multimorbidity in a Racial and Ethnic Diverse Sample of Middle-Aged and Older Adults. Innov Aging. 2019;3(2):igz016. doi: 10.1093/geroni/igz016 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 20.Salawu MM, Owoaje ET. Prevalence and Predictors of Adverse Childhood Experiences among Youths in Rural communities of Oyo State, South-west, Nigeria. J Com Med and PHC. 2020;32(2):27–41. doi: 10.4314/jcmphc.v32i2.3 [DOI] [Google Scholar]
  • 21.Vannorsdall TD, Munro CA. The link between childhood adversity and late-life mental health: evidence for the influence of early-life experiences or illusory correlations?. Int Psychogeriatr. 2017;29(3):357–8. doi: 10.1017/S1041610216002416 [DOI] [PubMed] [Google Scholar]
  • 22.Brown DW, Anda RF, Tiemeier H, Felitti VJ, Edwards VJ, Croft JB, et al. Adverse childhood experiences and the risk of premature mortality. Am J Prev Med. 2009;37(5):389–96. doi: 10.1016/j.amepre.2009.06.021 [DOI] [PubMed] [Google Scholar]
  • 23.Bethell C, Jones J, Gombojav N, Linkenbach J, Sege R. Positive Childhood Experiences and Adult Mental and Relational Health in a Statewide Sample: Associations Across Adverse Childhood Experiences Levels. JAMA Pediatr. 2019;173(11):e193007. doi: 10.1001/jamapediatrics.2019.3007 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 24.Lacey RE, Minnis H. Practitioner Review: Twenty years of research with adverse childhood experience scores - Advantages, disadvantages and applications to practice. J Child Psychol Psychiatry. 2020;61(2):116–30. doi: 10.1111/jcpp.13135 [DOI] [PubMed] [Google Scholar]

Decision Letter 0

Mithun Sikdar

9 Feb 2026

Dear Dr. Asiamah,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

Please submit your revised manuscript by Mar 26 2026 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

  • A letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.

  • A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.

  • An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols. Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols.

We look forward to receiving your revised manuscript.

Kind regards,

Mithun Sikdar

Academic Editor

PLOS One

Journal Requirements:

When submitting your revision, we need you to address these additional requirements.

1.Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at

https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and

https://journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf

2. Please include captions for your Supporting Information files at the end of your manuscript, and update any in-text citations to match accordingly. Please see our Supporting Information guidelines for more information: http://journals.plos.org/plosone/s/supporting-information.

3. We are unable to open your Supporting Information file “Data.sav and PONE-D-25-04688 _proof.pdf” Please kindly revise as necessary and re-upload.

4. If the reviewer comments include a recommendation to cite specific previously published works, please review and evaluate these publications to determine whether they are relevant and should be cited. There is no requirement to cite these works unless the editor has indicated otherwise.

Additional Editor Comments:

Considering the reviewers’ comments, the paper requires major revision. I believe the authors will make the necessary effort to revise the manuscript in accordance with the reviewers’ suggestions.

[Note: HTML markup is below. Please do not edit.]

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

Reviewer #1: Yes

Reviewer #2: Yes

**********

2. Has the statistical analysis been performed appropriately and rigorously? -->?>

Reviewer #1: No

Reviewer #2: Yes

**********

3. Have the authors made all data underlying the findings in their manuscript fully available??>

The PLOS Data policy

Reviewer #1: Yes

Reviewer #2: Yes

**********

4. Is the manuscript presented in an intelligible fashion and written in standard English??>

Reviewer #1: Yes

Reviewer #2: Yes

**********

Reviewer #1: This manuscript addresses an important topic and offers useful evidence on the association between ACEs and multimorbidity among older adults in Nigeria, but several issues require attention before publication. The writing, while understandable, contains frequent grammatical and structural problems that need editing for clarity and academic tone. Methodological limitations, particularly the cross-sectional hospital-based design, categorization of count variables, and very large, imprecise odds ratios as well as limit causal interpretation and warrant more cautious conclusions. The manuscript also lacks a formal Data Availability Statement, and details on missing data handling and model diagnostics are insufficient. Ethics approval appears appropriate, and no concerns about misconduct arise, but the introduction, methods, and discussion would benefit from clearer organization and more consistent reporting. With revisions to improve language, transparency, analytical justification, and framing of conclusions, the study could make a meaningful contribution to life-course research. A full review has been uploaded for your consideration

Reviewer #2: 1.You can state that it is a clinic geriatric study because it is studied on the OPD hospitals not on the community of Nigeria or not the randomly sampled healthy older adults.

2.Given that socioeconomic conditions in Nigeria are deeply embedded within cultural practices and extended family systems, certain ACE items related to neglect, household instability, or economic hardship may be culturally contextual rather than purely adverse. This raises the possibility of some ACE indicators may be subject to bias or overestimation of ACE exposure.

3.Author can mention that they have used the binary version for calculating the ACE cumulative scores.

4.While this study employs the standardized ACE framework like Neglect, abuse, violence etc. ACE should also be understood localized ACE construct like food insecurity and child labor as a salient childhood stressor which are not properly captured in ACE questionnaire.

4.Glaucoma, Cataract, Obesity, Liver Cirrhosis, arthritis, Osteoporosis though falls under expanded chronic diseases criteria of WHO. Does it also fall under PURE defined chronic diseases?

**********

what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy

Reviewer #1: No

Reviewer #2: Yes:  TANUSHREE BARMAN

**********

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

To ensure your figures meet our technical requirements, please review our figure guidelines: https://journals.plos.org/plosone/s/figures

You may also use PLOS’s free figure tool, NAAS, to help you prepare publication quality figures: https://journals.plos.org/plosone/s/figures#loc-tools-for-figure-preparation.

NAAS will assess whether your figures meet our technical requirements by comparing each figure against our figure specifications.

Attachment

Submitted filename: Manuscript Review (PONE-D-25-20171)..pdf

pone.0358944.s002.pdf (192.3KB, pdf)
Attachment

Submitted filename: Manuscript Revised final.docx

pone.0358944.s003.docx (87.4KB, docx)

Decision Letter 1

Mithun Sikdar

8 May 2026

Dear Dr. Asiamah,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

Dear Authors,

I appreciate the effort you have put into improving the manuscript; however, it still requires further revision.

Page 3:

Please elaborate the larger part of the study on which the present study is based.

Please revise the abstract to reflect a clearer scientific orientation. The use of a “chronological approach” needs clarification, does the study incorporate a longitudinal design to determine the onset and progression of multimorbidity? It appears that such an approach has not been employed. Rather, the study seems to rely on current prevalence of multimorbidity alongside retrospective assessment of adverse childhood experiences (ACEs), which would more appropriately classify it as an analytical observational study. Please revise the abstract.

Additionally, the manuscript requires careful linguistic refinement to meet the standards of a reputed journal such as PLOS ONE .

Several sentences are overly long and at times difficult to follow, affecting overall clarity and readability. For example:

Page 1

“Face-to-face data was collected from a cross-section of 734 patients aged 60 years and over with 2 or more chronic diseases who visit for routine outpatient care and consented to participate in the study”.

Page 8

“It has been found in Table 3 that ACEs is strongly associated with multimorbidity as indicated by Chi-squared test (<img height="21" src="data:image/png;base64,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" width="17" />=116.07, p<.001) which means that multimorbidity in old age is associated with ACEs. Older adults who had experienced 4 or more ACEs are found to have suffered more with 3+ diseases compared to older people with <3 diseases. Other selected covariates such as age, gender, marital status, occupation, education, income, family structure are also found to be statistically associated with multimorbidity. However, ethnicity is found to be not statistically associated with multimorbidity in the study.”

The method part needs elaboration.

I have appended the revisions suggested by the reviewers. They have recommended major revisions before the manuscript can be considered suitable for publication.

Reviewer 1:

Generally, the manuscript has improved; however, several critical issues remain that need to be addressed before it can be considered for publication.

Firstly: the use of causal language is still evident and is not appropriate for a cross-sectional study design.

Phrases such as “predicts multimorbidity” and “demonstrating a clear dose-response relationship” imply causality and should be revised to reflect associations only (example, “is associated with,” “is linked to,” or “shows a dose–response pattern”).

Secondly:

- the Methods section remains insufficiently detailed. While it is noted that this study is part of a larger study, the manuscript must be self-contained, as readers may not have access to the parent study.

A clear and explicit description of the study design (e.g., cross-sectional hospital-based study) should be provided upfront. Additionally, key methodological details are still missing or unclear, including the sampling frame, inclusion and exclusion criteria, ACE-IQ scoring approach, regression model specification, handling of missing data, and clarification of reliability measures such as Cronbach’s alpha.

The current description still does not adequately address concerns.

Thirdly:

- concerns regarding the logistic regression analysis have not been addressed.

- The reported large odds ratios, wide confidence intervals, and potential model instability require explanation.

- This is a significant issue that should be discussed, with possible reasons such as sparse data bias, small subgroup sizes, or effects of variable categorization clearly articulated in the Discussion.

Fourthly:

- the justification for using a cutoff of three or more diseases remains unclear.

- This threshold should be supported by appropriate references or a clear rationale (example, clinical relevance or distribution-based justification).

Fifthly:

- the Results section still contains interpretative language.

- Statements such as “strongly associated” and “found to have suffered more” should be revised to ensure that results are presented in a strictly objective and descriptive manner, with interpretation reserved for the Discussion.

- Additionally, there are instances of inappropriate or overstated claims in the manuscript. For example, statements such as “To the best of our knowledge, this is the first study that analyses the impact of ACEs on the health of older adults in Niger state north-central Nigeria” are not suitable for scientific writing unless they are clearly substantiated by a comprehensive and systematic literature search. Such claims are often difficult to verify and may be perceived as overstated. It is recommended to either remove such statements or rephrase them more cautiously (example, “This study contributes to the limited body of literature on…”).

Finally:

- the discussion of bias and limitations is still underdeveloped.

- Important sources of bias, including selection bias, survivor bias, recall bias, and residual confounding, should be more thoroughly addressed to strengthen the rigor and transparency of the manuscript.

Overall, while revisions have been made, substantial improvements are still required.

Generally, the manuscript has improved; however, several critical issues remain that need to be addressed before it can be considered for publication.

Firstly:

- the use of causal language is still evident and is not appropriate for a cross-sectional study design.

Phrases such as “predicts multimorbidity” and “demonstrating a clear dose–response relationship” imply causality and should be revised to reflect associations only (example, “is associated with,” “is linked to,” or “shows a dose–response pattern”).

Secondly:

- the Methods section remains insufficiently detailed. While it is noted that this study is part of a larger study, the manuscript must be self-contained, as readers may not have access to the parent study.

A clear and explicit description of the study design (e.g., cross-sectional hospital-based study) should be provided upfront. Additionally, key methodological details are still missing or unclear, including the sampling frame, inclusion and exclusion criteria, ACE-IQ scoring approach, regression model specification, handling of missing data, and clarification of reliability measures such as Cronbach’s alpha.

The current description still does not adequately address concerns.

Thirdly:

- concerns regarding the logistic regression analysis have not been addressed.

- The reported large odds ratios, wide confidence intervals, and potential model instability require explanation.

- This is a significant issue that should be discussed, with possible reasons such as sparse data bias, small subgroup sizes, or effects of variable categorization clearly articulated in the Discussion.

Fourthly:

- the justification for using a cutoff of three or more diseases remains unclear.

- This threshold should be supported by appropriate references or a clear rationale (example, clinical relevance or distribution-based justification).

Fifthly:

- the Results section still contains interpretative language.

- Statements such as “strongly associated” and “found to have suffered more” should be revised to ensure that results are presented in a strictly objective and descriptive manner, with interpretation reserved for the Discussion.

- Additionally, there are instances of inappropriate or overstated claims in the manuscript. For example, statements such as “To the best of our knowledge, this is the first study that analyses the impact of ACEs on the health of older adults in Niger state north-central Nigeria” are not suitable for scientific writing unless they are clearly substantiated by a comprehensive and systematic literature search. Such claims are often difficult to verify and may be perceived as overstated. It is recommended to either remove such statements or rephrase them more cautiously (example, “This study contributes to the limited body of literature on…”).

Finally:

- the discussion of bias and limitations is still underdeveloped.

- Important sources of bias, including selection bias, survivor bias, recall bias, and residual confounding, should be more thoroughly addressed to strengthen the rigor and transparency of the manuscript.

Overall, while revisions have been made, substantial improvements are still required.

Reviewer 2

Justify why there is a big difference in the odds ratio. The odds ratio between 0 morbidity and 4 or more morbidities is very high.

==============================

Please submit your revised manuscript by Jun 22 2026 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

Please include the following items when submitting your revised manuscript:

  • A letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.

  • A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.

  • An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols. Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols.

As the corresponding author, your ORCID iD is verified in the submission system and will appear in the published article. PLOS supports the use of ORCID, and we encourage all coauthors to register for an ORCID iD and use it as well. Please encourage your coauthors to verify their ORCID iD within the submission system before final acceptance, as unverified ORCID iDs will not appear in the published article. Only the individual author can complete the verification step; PLOS staff cannot verify ORCID iDs on behalf of authors.

We look forward to receiving your revised manuscript.

Kind regards,

Mithun Sikdar

Academic Editor

PLOS One

Journal Requirements:

If the reviewer comments include a recommendation to cite specific previously published works, please review and evaluate these publications to determine whether they are relevant and should be cited. There is no requirement to cite these works unless the editor has indicated otherwise.

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

Reviewer #1: (No Response)

Reviewer #2: All comments have been addressed

**********

2. Is the manuscript technically sound, and do the data support the conclusions??>

Reviewer #1: Partly

Reviewer #2: Yes

**********

3. Has the statistical analysis been performed appropriately and rigorously? -->?>

Reviewer #1: Yes

Reviewer #2: No

**********

4. Have the authors made all data underlying the findings in their manuscript fully available??>

The PLOS Data policy

Reviewer #1: Yes

Reviewer #2: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English??>

Reviewer #1: Yes

Reviewer #2: Yes

**********

Reviewer #1: Review of PONE-D-25-20171R1

Generally, the manuscript has improved; however, several critical issues remain that need to be addressed before it can be considered for publication.

Firstly:

- the use of causal language is still evident and is not appropriate for a cross-sectional study design.

Phrases such as “predicts multimorbidity” and “demonstrating a clear dose–response relationship” imply causality and should be revised to reflect associations only (example, “is associated with,” “is linked to,” or “shows a dose–response pattern”).

Secondly:

- the Methods section remains insufficiently detailed. While it is noted that this study is part of a larger study, the manuscript must be self-contained, as readers may not have access to the parent study.

A clear and explicit description of the study design (e.g., cross-sectional hospital-based study) should be provided upfront. Additionally, key methodological details are still missing or unclear, including the sampling frame, inclusion and exclusion criteria, ACE-IQ scoring approach, regression model specification, handling of missing data, and clarification of reliability measures such as Cronbach’s alpha.

The current description still does not adequately address concerns.

Thirdly:

- concerns regarding the logistic regression analysis have not been addressed.

- The reported large odds ratios, wide confidence intervals, and potential model instability require explanation.

- This is a significant issue that should be discussed, with possible reasons such as sparse data bias, small subgroup sizes, or effects of variable categorization clearly articulated in the Discussion.

Fourthly:

- the justification for using a cutoff of three or more diseases remains unclear.

- This threshold should be supported by appropriate references or a clear rationale (example, clinical relevance or distribution-based justification).

Fifthly:

- the Results section still contains interpretative language.

- Statements such as “strongly associated” and “found to have suffered more” should be revised to ensure that results are presented in a strictly objective and descriptive manner, with interpretation reserved for the Discussion.

- Additionally, there are instances of inappropriate or overstated claims in the manuscript. For example, statements such as “To the best of our knowledge, this is the first study that analyses the impact of ACEs on the health of older adults in Niger state north-central Nigeria” are not suitable for scientific writing unless they are clearly substantiated by a comprehensive and systematic literature search. Such claims are often difficult to verify and may be perceived as overstated. It is recommended to either remove such statements or rephrase them more cautiously (example, “This study contributes to the limited body of literature on…”).

Finally:

- the discussion of bias and limitations is still underdeveloped.

- Important sources of bias, including selection bias, survivor bias, recall bias, and residual confounding, should be more thoroughly addressed to strengthen the rigor and transparency of the manuscript.

Overall, while revisions have been made, substantial improvements are still required.

Reviewer #2: Justify why there is a big difference in the odds ratio. The odds ratio between 0 morbidity and 4 or more morbidities is very high.

**********

what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy

Reviewer #1: No

Reviewer #2: Yes:  Tanushree Barman

**********

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

To ensure your figures meet our technical requirements, please review our figure guidelines: https://journals.plos.org/plosone/s/figures

You may also use PLOS’s free figure tool, NAAS, to help you prepare publication quality figures: https://journals.plos.org/plosone/s/figures#loc-tools-for-figure-preparation.

NAAS will assess whether your figures meet our technical requirements by comparing each figure against our figure specifications.

Attachment

Submitted filename: Manuscript.docx

pone.0358944.s005.docx (63.9KB, docx)

Decision Letter 2

Mithun Sikdar

17 Jul 2026

Dear Dr. Asiamah,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

Please submit your revised manuscript by Aug 31 2026 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

  • A letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.

  • A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.

  • An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols. Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols.

As the corresponding author, your ORCID iD is verified in the submission system and will appear in the published article. PLOS supports the use of ORCID, and we encourage all coauthors to register for an ORCID iD and use it as well. Please encourage your coauthors to verify their ORCID iD within the submission system before final acceptance, as unverified ORCID iDs will not appear in the published article. Only the individual author can complete the verification step; PLOS staff cannot verify ORCID iDs on behalf of authors.

We look forward to receiving your revised manuscript.

Kind regards,

Mithun Sikdar

Academic Editor

PLOS One

Journal Requirements:

If the reviewer comments include a recommendation to cite specific previously published works, please review and evaluate these publications to determine whether they are relevant and should be cited. There is no requirement to cite these works unless the editor has indicated otherwise.

Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice.

Additional Editor Comments:

The revised manuscript is substantially improved, with a much clearer and more coherent flow of writing. Although the second reviewer was not available to evaluate the revised manuscript, I took the initiative to review the entire revised version and suggest the minor revisions that both the first reviewer and I considered necessary. The crude OR of 67.14 is extremely high and the confidence interval is extremely wide, spanning from 9.25 to 487.04. The adjustment substantially reduced the OR from 67 to 15.58. The findings support a significant association between ACEs and multimorbidity, but the reported odds ratios, particularly the crude OR of 67.14 and the adjusted OR with a 95% CI of 1.33-182.21 are too imprecise to support a confident claim about the true effect size. The association is likely real, but the magnitude should be interpreted with considerable caution.

It is good that the authors have accepted the limitation of recall bias (The high prevalence of ACEs reported in this cohort must be interpreted cautiously. Although participants were provided sufficient time to recall pre-18 experiences, retrospective reporting may still be influenced by recall bias, particularly among older age groups). How this recall bias can influence the results can also be little elaborated.

The reviewer raised two important methodological concerns that should be addressed in the revised manuscript.

First, the reviewer requested clarification regarding model diagnostics, stating:

"Model fit was assessed using VIF or the Hosmer-Lemeshow goodness-of-fit test? Please include the results of the Hosmer-Lemeshow test and the variance inflation factors (VIFs), either in the main text or as supplementary material."

Accordingly, the manuscript should clearly describe the procedures used to assess model fit and multicollinearity. If these analyses were performed, the corresponding results should be presented either in the main manuscript or as supplementary material.

Second, the reviewer commented on the marked change in the odds ratio following multivariable adjustment:

"The substantial reduction in the odds ratio after multivariable adjustment (from 67.14 to 15.58) needs further discussion. While the adjusted association remains statistically significant, the manuscript does not explain the likely reasons for this reduction. A brief discussion of the role of confounding by the adjusted socio-demographic variables would help to better interpret the effect of ACE exposure. If possible, the authors may also indicate which covariates contributed most to the reduction in the effect estimate." This point warrants a more detailed discussion. The authors should explain that the attenuation of the odds ratio following multivariable adjustment is indicative of confounding by the socio-demographic variables included in the model. If feasible, they should also identify the covariate(s) that contributed most to the reduction in the effect estimate, thereby providing a clearer interpretation of the independent association between ACE exposure and the study outcome.

May I request the authors to include the methodology as supplementary material rather than simply referring readers to previous publications for methodological details?

I believe the authors will be able to address these minor revisions before the manuscript is published in its present form.

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

Reviewer #2: All comments have been addressed

**********

2. Is the manuscript technically sound, and do the data support the conclusions??>

Reviewer #2: Yes

**********

3. Has the statistical analysis been performed appropriately and rigorously? -->?>

Reviewer #2: No

**********

4. Have the authors made all data underlying the findings in their manuscript fully available??>

The PLOS Data policy

Reviewer #2: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English??>

Reviewer #2: Yes

**********

Reviewer #2: 1.Model fit was assessed using VIF OR Hosmer–Lemeshow goodness-of-fit test? Please paste these results (Hosmer–Lemeshow test and (VIFs)) either in the main text or as supplementary material. Both the Pdf and word file have different versions.

2.In the statistical analysis section-The substantial reduction in the odds ratio after multivariable adjustment (from 67.14 to 15.58) needs further discussion. While the adjusted association remains statistically significant, the manuscript does not explain the likely reasons for this reduction. A brief discussion of the role of confounding by the adjusted socio-demographic variables would help to interpret better the effect of ACE exposure. If possible, the authors may also indicate which covariates contributed most to the reduction in the effect estimate.

**********

what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy

Reviewer #2: Yes:  TANUSHREE BARMAN

**********

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

To ensure your figures meet our technical requirements, please review our figure guidelines: https://journals.plos.org/plosone/s/figures

You may also use PLOS’s free figure tool, NAAS, to help you prepare publication quality figures: https://journals.plos.org/plosone/s/figures#loc-tools-for-figure-preparation.

NAAS will assess whether your figures meet our technical requirements by comparing each figure against our figure specifications.

Attachment

Submitted filename: Manuscript (7) R.docx

pone.0358944.s007.docx (66.5KB, docx)
PLoS One. 2026 Sep 25;21(9):e0358944. doi: 10.1371/journal.pone.0358944.r006

Author response to Decision Letter 3


19 Aug 2026

Dear Editor,

We are grateful for your careful re-evaluation of our revised manuscript and for the constructive and insightful comments provided. We appreciate your initiative in reviewing the manuscript in the absence of the second reviewer and for highlighting areas requiring further clarification. We have addressed all comments thoroughly and revised the manuscript accordingly to enhance its methodological transparency, analytical rigor, and interpretative balance. Our detailed responses are presented below.

1. Magnitude and Precision of the Reported Odds Ratios

We acknowledge the concern regarding the magnitude and imprecision of the crude (OR = 67.14; 95% CI: 9.25–487.04) and adjusted odds ratios (OR = 15.58; 95% CI: 1.33–182.21). In the revised manuscript, we have:

• Explicitly emphasized that while the association between ACEs and multimorbidity is statistically significant, the effect size should be interpreted with caution due to wide confidence intervals.

• Added text in the section explaining that the wide intervals likely reflect sparse data in some exposure categories and variability in responses, limiting precision (page 10, line 314 to 316).

2. Further Elaboration on Recall Bias

We appreciate the recognition of our acknowledgment of recall bias and have expanded this section further. Specifically, we now clarify that:

• Retrospective reporting of adverse childhood experiences (ACEs), particularly among older participants, is susceptible to differential and non-differential misclassification.

• Recall bias may lead to systematic over-reporting (due to current health status influencing recollection) or under-reporting (due to memory decay or social desirability), thereby potentially biasing effect estimates in either direction.

• This limitation has been more explicitly articulated in the manuscript to ensure a balanced interpretation of findings.

(Page 13, 399 to 408)

3. Model Diagnostics: Goodness-of-Fit and Multicollinearity

In response to the reviewer’s methodological query, we have strengthened the Methods and Results sections as follows:

• We have explicitly described the procedures used to assess model adequacy, including the Hosmer–Lemeshow goodness-of-fit test, which indicated acceptable model calibration.

• We assessed multicollinearity using Variance Inflation Factors (VIFs), all of which were within acceptable thresholds, suggesting no evidence of problematic collinearity among covariates.

(Page 5, line 249 to 252)

4. Attenuation of the Odds Ratio Following Multivariable Adjustment

We agree that the substantial reduction in the odds ratio following adjustment warrants further explanation. Accordingly:

• We have expanded the Discussion to clarify that the attenuation from OR = 67.14 to OR = 15.58 reflects confounding by socio-demographic variables included in the multivariable model.

• Specifically, factors such as age, educational attainment, and socioeconomic status partially accounted for the crude association, indicating that these variables are important determinants of both ACE exposure and multimorbidity.

• Where analytically feasible, we have indicated the covariate(s) that contributed most to the reduction in the effect estimate, thereby providing a clearer interpretation of the independent association between ACE exposure and multimorbidity.

• This additional discussion strengthens the causal interpretability of our findings while maintaining appropriate caution.

• (page 10, line 314 to 316).

5. Inclusion of Methodological Details as Supplementary Material

In line with your recommendation, we have included a comprehensive description of the study methodology, rather than referring readers to prior publications alone. This includes:

• Sampling procedures

• Measurement of ACEs and multimorbidity

• Data collection protocols

• Analytical framework

(Pages 3 to 4, lines 174 to 189)

This addition enhances the manuscript’s transparency and allows for independent appraisal of the study design and execution.

In summary, we have carefully addressed all comments and believe that the revisions have substantially improved the clarity, methodological robustness, and interpretative balance of the manuscript. We are grateful for the opportunity to refine our work and for the valuable guidance provided.

Thank you for your consideration.

Yours sincerely,

Nestor Asiamah

On behalf of all authors

Attachment

Submitted filename: Authors Response.docx

pone.0358944.s008.docx (21.8KB, docx)

Decision Letter 3

Mithun Sikdar

9 Sep 2026

The Impact of Adverse Childhood Experiences on the Development of Multimorbidity in Older Adults in Nigeria

PONE-D-25-20171R3

Dear Dr.Nestor Asiamah,

We’re pleased to inform you that your manuscript has been judged scientifically and it is now suitable for publication. It will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

An invoice will be generated when your article is formally accepted. Please note, if your institution has a publishing partnership with PLOS and your article meets the relevant criteria, all or part of your publication costs will be covered. Please make sure your user information is up-to-date by logging into Editorial Manager at Editorial Manager® and clicking the ‘Update My Information' link at the top of the page. For questions related to billing, please contact billing support.

If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org.

As a minor editorial point, I suggest that you include a brief statement at the end of the manuscript regarding the use of any AI-based tools during manuscript preparation, including language editing, proofreading, or other forms of editorial assistance, if applicable.

Kind regards,

Mithun Sikdar

Academic Editor

PLOS One

Acceptance letter

Mithun Sikdar

PONE-D-25-20171R3

PLOS One

Dear Dr. Asiamah,

I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS One. Congratulations! Your manuscript is now being handed over to our production team.

At this stage, our production department will prepare your paper for publication. This includes ensuring the following:

* All references, tables, and figures are properly cited

* All relevant supporting information is included in the manuscript submission,

* There are no issues that prevent the paper from being properly typeset

You will receive further instructions from the production team, including instructions on how to review your proof when it is ready. Please keep in mind that we are working through a large volume of accepted articles, so please give us a few days to review your paper and let you know the next and final steps.

Lastly, if your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org.

You will receive an invoice from PLOS for your publication fee after your manuscript has reached the completed accept phase. If you receive an email requesting payment before acceptance or for any other service, this may be a phishing scheme. Learn how to identify phishing emails and protect your accounts at https://explore.plos.org/phishing.

If we can help with anything else, please email us at customercare@plos.org.

Thank you for submitting your work to PLOS One and supporting open access.

Kind regards,

PLOS One Editorial Office Staff

on behalf of

Dr. Mithun Sikdar

Academic Editor

PLOS One

Associated Data

    This section collects any data citations, data availability statements, or supplementary materials included in this article.

    Supplementary Materials

    S1 Data. Quantitative data.

    (XLS)

    pone.0358944.s001.xls (703KB, xls)
    Attachment

    Submitted filename: Manuscript Review (PONE-D-25-20171)..pdf

    pone.0358944.s002.pdf (192.3KB, pdf)
    Attachment

    Submitted filename: Manuscript Revised final.docx

    pone.0358944.s003.docx (87.4KB, docx)
    Attachment

    Submitted filename: AUTHORS RESPONSE TO REVIEWERS.docx

    pone.0358944.s004.docx (23KB, docx)
    Attachment

    Submitted filename: Manuscript.docx

    pone.0358944.s005.docx (63.9KB, docx)
    Attachment

    Submitted filename: Response to Editor and Reviewers.docx

    pone.0358944.s006.docx (23.8KB, docx)
    Attachment

    Submitted filename: Manuscript (7) R.docx

    pone.0358944.s007.docx (66.5KB, docx)
    Attachment

    Submitted filename: Authors Response.docx

    pone.0358944.s008.docx (21.8KB, docx)

    Data Availability Statement

    The data used for this study is attached as supplementary information. The name of the data file is “Data”.


    Articles from PLOS One are provided here courtesy of PLOS

    RESOURCES