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PLOS One logoLink to PLOS One
. 2024 Apr 2;19(4):e0299098. doi: 10.1371/journal.pone.0299098

Association between the COVID-19 pandemic and mental health in very old people in Sweden

Fanny Jonsson 1, Birgitta Olofsson 2,3, Stefan Söderberg 4,, Johan Niklasson 1,‡,*
Editor: Mario Ulises Pérez-Zepeda5
PMCID: PMC10986980  PMID: 38564616

Abstract

Background

During the COVID-19 pandemic, Sweden implemented social distancing measures to reduce infection rates. However, the recommendation meant to protect individuals particularly at risk may have had negative consequences. The aim of this study was to investigate the impact of the COVID-19 pandemic on very old Swedish peoples’ mental health and factors associated with a decline in mental health.

Methods

We conducted a cross-sectional study among previous participants of the SilverMONICA (MONItoring of Trends and Determinants of CArdiovascular disease) study. Of 394 eligible participants, 257 (65.2%) agreed to participate. Of these, 250 individuals reported mental health impact from COVID-19. Structured telephone interviews were carried out during the spring of 2021. Data were analysed using the χ2 test, t-test, and binary logistic regression.

Results

Of 250 individuals (mean age: 85.5 ± 3.3 years, 54.0% women), 75 (30.0%) reported a negative impact on mental health, while 175 (70.0%) reported either a positive impact (n = 4) or no impact at all (n = 171). In the binary logistic regression model, factors associated with a decline in mental health included loneliness (odds ratio [95% confidence interval]) (3.87 [1.83–8.17]) and difficulty adhering to social distancing recommendations (5.10 [1.92–13.53]). High morale was associated with positive or no impact on mental health (0.37 [0.17–0.82]).

Conclusions

A high percentage of very old people reported a negative impact on mental health from the COVID-19 pandemic, primarily from loneliness and difficulty adhering to social distancing measures, while high morale seemed to be a protective factor.

1. Introduction

Since the beginning of the COVID-19 outbreak, there have been over 525 million confirmed cases and almost 6.3 million deaths globally [1]. In Sweden, a country with almost 10.5 million inhabitants [2], more than 2.5 million cases have been confirmed, and almost 19,000 deaths have been reported [1], with the highest death rate among the oldest old [3]. The World Health Organisation declared the COVID-19 outbreak a pandemic on March 11, 2020 [4], and soon after, many countries implemented various states of social distancing to reduce the spread of infection. In Sweden, people over 70 years were advised to limit social interactions to a higher degree than the rest of the population [5].

As older people were at higher risk of suffering negative outcomes related to COVID-19 regardless of comorbidities [6], social distancing was implemented to protect those particularly at risk. However, the recommendation thought to act as a protective measure has also negatively impacted mental health. Several studies have described mental health consequences from social distancing during COVID-19, such as depressive symptoms, anxiety, poor sleep quality [7], loneliness [8, 9] and subjective health impacts [10]. However, contradictory results have been presented, such as low levels of depression and anxiety among the participants [11].

Possible explanations for these positive outcomes include mental resilience through life experiences such as growing up during the Second World War years and exposure to previous pandemics [11], as well as inherent aspects of mental resilience. One of the latter is morale, defined by Lawton in the 1970s as “a generalized feeling of well-being with diverse specific indicators such as freedom from distressing symptoms, satisfaction with self, feeling of syntony between self and environment, and ability to strive appropriately, while still accepting the inevitable” [12]. Higher morale, that is, future-oriented optimism [13], is associated not only with increased longevity [14, 15], but with lower risk of depressive disorders as well [16].

However, the studies mentioned above evaluated older people’s experiences only during the first months of social distancing during COVID-19, and none were conducted with samples that exclusively included the oldest old (aged 80 or older) [711]. Lastly, it is unclear whether these conclusions are applicable to a Swedish context since these studies were conducted in countries with preventive measures that led to society being shut down to a greater extent than it was under the Swedish COVID-19 strategy, which was based on voluntary action and personal responsibility [17].

The purpose of this study was to investigate the impact the COVID-19 pandemic had on Swedish older peoples’ mental health and factors associated with a decline in mental health.

2. Material and methods

2.1 Study design

The SilverMONICA COVID-19 survey is a follow-up of individuals who previously participated in the SilverMONICA (MONItoring of Trends and Determinants of CArdiovascular disease) study, which was a follow-up study of previous participants from the Northern Sweden MONICA study performed in 1999. Inclusion criteria were being 80 years or older during the study period 2016–2019 and living in either of the two northernmost counties of Sweden (Norrbotten or Västerbotten). The MONICA [18] and SilverMONICA [19] studies have previously been presented in detail.

2.2 Participants

The inclusion criteria for the SilverMONICA COVID-19 survey were previous participation in the SilverMONICA study when consent to future contacts was obtained. No exclusion criteria were implemented. A total of 394 individuals were eligible for participation, of whom 257 (65.2%) agreed to participate. Reasons for not participating were the following: emigrated or unable to reach (n = 11), declined participation (n = 57), declined because of health-related reasons and/or cognitive impairment (n = 58), or deceased (n = 11). Of the 257 individuals who participated, 250 answered the survey statement, “I feel that the COVID-19 pandemic has affected my mental health”, and these individuals constituted the final sample.

2.3 Data collection

The Silver-MONICA study was performed with interviews in the participants’ own homes, but due to the risk of spreading COVID-19, interviews, including home visits, were deemed inappropriate for the Silver MONICA COVID-19 follow-up. Instead, structured telephone interviews were carried out. Data collection occurred during the spring of 2021, starting in January and ending in June. An experienced research nurse conducted a vast majority of telephone interviews, while a few of the interviews were led by a specially trained student nurse, and both were purposely trained before the study. Participants were offered breaks during the interview process, as well as the possibility to continue later if needed. Most respondents could complete the interview independently, while in a few interviews were conducted with the support of relatives.

2.4 Measurements

2.4.1 Outcome variable

The impact on mental health was surveyed with the question, “I feel that the COVID-19 pandemic has affected my mental health”, where answer alternatives included “for the better”, “unaffected”, and “for the worse” (0 = positive/no impact, 1 = negative impact).

2.4.2 Sociodemographic factors

For educational level, 13 or more years of schooling indicated a high educational level in accordance with Waller et al. [20]. For residential status, answer alternatives included “residing alone”, “residing with significant other”, and “residing with children or grandchildren” (0 = residing with other people, 1 = residing alone). Data regarding educational status, educational level, place of residence and residential status were retrieved from the SilverMONICA baseline (2016–2019).

2.4.3 Health-related factors

Self-rated health was based on the 36-Item Short Form Survey (SF-36) item “In general, would you say your health is:”, and answer alternatives were dichotomized (0 = excellent/very good/good, 1 = fair/poor) [21, 22]. Self-rated health compared to one year ago was based on the SF-36 item “Compared to one year ago, how would you rate your health in general now?” [21, 22], and the answer alternatives were dichotomized (0 = better/about the same as one year ago, 1 = worse than one year ago).

Sense of security was dichotomised (0 = secure, 1 = insecure/hard to tell), where “hard to tell” was dichotomized as worse, with the justification that individuals who stated that it was hard to tell whether they felt secure or not could not, likely were insecure. Perceived loneliness was dichotomised by merging the answers “rarely” and “never” and the answers “often” and “sometimes” (0 = no, 1 = yes).

The 15-item version of the Geriatric Depression Scale (GDS-15) [23, 24] is an assessment of depressive symptoms in older individuals. The scale consists of 15 questions, with scores ranging from 0 to 15. A score ≥5 is considered to indicate depression, following Conradsson et al. [25], ≥14 answered questions were regarded as a minimum for inclusion in the study.

The Philadelphia Geriatric Center Morale Scale (PGCMS) was used to assess morale in very old people [12]. The scale consists of 17 questions with answer alternatives “yes” or “no”, where points are given for answers indicating high morale. Scores range from 0 to 17, through which level of morale is categorised as either low (0–9), mid-range (10–12), or high (13–17) [26]. The psychometric properties of the Swedish translation of the scale and its feasibility among very old people have been found satisfactory [27]. In line with a previous study by Niklasson et al. [16], ≥12 answered questions were regarded as a minimum for inclusion in the present study.

The Mini-Mental State Examination (MMSE) [28] assesses cognitive function that includes orientation, registration, attention and calculation, recall, language, and copying. Scores range from 0 to 30, with a score of ≤23 indicating significant cognitive impairment [29]. Dependence in instrumental activities of daily living (I-ADL) and personal activities of daily living (P-ADL) was measured with the Katz ADL staircase [30]. To be deemed as independent in I-ADL the participants had to be independent in all the following activities: cleaning, shopping, transport, and cooking. To be deemed independent in P-ADL, the participants had to be independent in all the following activities: bathing, dressing, toileting, transfer, continence, and eating. Mean gait speed at the usual pace (metres per second [m/s], measured over 2.4 m) was included as a surrogate marker for frailty by Weidung et al. [31]. Individuals were considered to have impaired hearing if the respondent reported that they could not hear someone speaking in a normal tone of voice from 1 metre away, with or without hearing aids. Data regarding MMSE score, dependence in I-ADL, dependence in P-ADL, gait speed and impaired hearing were retrieved from the SilverMONICA baseline (2016–2019).

Participants were asked if they knew if they had had COVID-19 infection. Approximately 15% of the participant’s medical records were randomly selected to be reviewed for COVID-19 test results.

2.4.4 Social factors

Difficulty adhering to social distancing recommendations was based on the question “How easy has it been for you to follow the Public Health Agency of Sweden’s recommendation regarding social distancing?”. The variable was dichotomised by merging the answer alternatives “very easy” and “somewhat easy”, and the answer alternatives “very difficult”, “somewhat difficult” and “I do not know”, with the justification that individuals who stated that they did not know whether it had been easy to adhere to social distancing recommendations cannot have found it easy to do so (0 = easy, 1 = difficult).

The answer alternatives were dichotomised for subjective impact on the social situation by COVID-19 (0 = positive/no impact, 1 = negative impact). Experience of not receiving the required amount of help was based on the question, “Do you receive the help that you feel you require from others (home help services, relatives etc.)?”, and answers were dichotomized (0 = yes, 1 = no). For regular visits from home-help services, answer alternatives included “no” and “yes” (0 = no, 1 = yes), and “I do not know” answers were coded as missing.

The variables “frequency of physical contacts” and “frequency of non-physical contacts” were further divided into the frequency of physical and non-physical contacts with family members, relatives, friends, neighbours, and people not otherwise specified. For each subcategory, answer alternatives included “more contact”, “less contact”, “no difference in contact”, “I have no contact with [subcategory]”, and “I do not know”. Subjects who selected the answer alternative “I do not know” were coded as missing.

For the variable “frequency of physical contacts”, we sought to investigate any eventual decrease in frequency. Therefore, subcategories were dichotomised by merging the answer alternatives “more contact”, “no difference in contact”, and “I have no contact with [subcategory]”, thus leaving dichotomous subcategories (0 = higher/same/no frequency of physical contacts, 1 = lower frequency of physical contacts).

In contrast, for the variable “frequency of non-physical contacts”, we sought to investigate any eventual increase in frequency. Subcategories were therefore dichotomised by merging the answer alternatives “less contact”, “no difference in contact”, and “I have no contact with [subcategory]”, thus leaving dichotomous subcategories (0 = lower/same/no frequency of non-physical contacts, 1 = higher frequency of non-physical contacts). The subcategory “one/more social networks” was created for both variables by computing each dichotomised subcategory.

Social distancing in this study was defined as avoiding crowded places, avoiding social contacts outside the family or persons in your household and keeping a longer physical distance from other people if crowded places had to be visited.

2.5 Statistics

For the univariable analyses, dichotomous variables were analysed using a χ2 test for independence or Fisher’s exact test, while continuous variables were analysed using an independent-samples t-test. To compare those with and without mental impact from COVID-19 some questions with multiple answer alternatives were dichotomized. Binary logistic regression was performed to analyse the influence of predictor variables on the odds that respondents would report a negative impact on their mental health by the COVID-19 pandemic. Any variable with a univariate p-value of <0.15 was selected as a candidate for the multivariable analysis [32]. For competing variables in similar areas, variables were selected based on the knowledge and experience of the author group to limit the number of independent variables to approximately one per 10 participants with the investigated outcome (negative impact on mental health). The final binary logistic regression model contained 8 covariates (sex, educational level, self-rated health compared to one year ago, perceived loneliness, PGCMS score, dependence in P-ADL, subjective impact on social situation by COVID-19, and difficulty adhering to social distancing recommendations).

All statistical tests were two-tailed. P-values of <0.05 were considered statistically significant. All statistical analyses were conducted using SPSS, Version 27.0.1.0.

3. Results

3.1 Sample characteristics

In the COVID-19 follow-up study population (n = 250), 135 (54.0%) were female. The mean age of the participants was 85.5 ± 3.3 years (range 81–96) at the time of the COVID-19 follow-up survey. Of the 250 respondents, 75 (30.0%) considered their mental health to be negatively affected by the COVID-19 pandemic, while 175 (70.0%) experienced either a positive impact (n = 4) or no effect at all (n = 171).

3.2 Sociodemographic factors

Sociodemographic factors concerning mental health are listed in Table 1, and these data were retrieved from the original SilverMONICA study. There were no statistical differences between those with and those without impact on mental health from COVID-19 regarding age, sex, mean number of years in school, level of education, place of residence, or residential status.

Table 1. Association between sociodemographic factors and mental health during the COVID-19 pandemic (N = 250).

Negative impact on mental health by COVID-19
Yes (N = 75) No (N = 175)
n (M ± SD) (%) n (M ± SD) (%) p
Age (years) 75 (85.4 ± 3.0) 175 (85.5 ± 3.5) 0.869
Sex (female) 48 of 75 (64.0) 87 of 175 (49.7) 0.053
Educational status (years of schooling)* (N = 247) 74 (10.5 ± 3.8) 173 (10.2 ± 4.0) 0.535
Educational level (high)* (N = 247) 24 of 74 (32.4) 38 of 173 (22.0) 0.115
Place of residence (number of inhabitants)* (N = 239) 0.733
    • Urban (≥15,000 inhabitants)* 37 of 72 (51.4) 79 of 167 (47.3)
    • Semiurban (1,000–14,999 inhabitants)* 19 of 72 (26.4) 43 of 167 (25.7)
    • Rural (<1,000 inhabitants)* 16 of 72 (22.2) 45 of 167 (26.9)
Residential status (residing alone)* (N = 244) 38 of 75 (50.7) 79 of 169 (46.7) 0.670

* Data retrieved from the SilverMONICA study (2016–2019).

Percentages are reported for dichotomous variables, while continuous variables are presented as mean ± standard deviation. Dichotomous variables were analysed using the χ2 test for independence, while continuous variables were analysed using an independent-samples t-test.

High level of education: ≥13 years of schooling.

3.3 Health-related factors

Health-related factors associated with the negative impact on mental health by COVID-19 were self-rated health, self-rated health worse than a year ago, perceived loneliness, GDS-15 score ≥5, and PGCMS ≥13 (Table 2). Table 2 also presents data from the original SilverMONICA study: MMSE-score, I-ADL, P-ADL, Gait speed and Hearing.

Table 2. Association between health-related factors and mental health during the COVID-19 pandemic (N = 250).

Negative impact on mental health by COVID-19
Yes (N = 75) No (N = 175)
n (M ± SD) (%) n (M ± SD) (%) p
Self-rated health (poor) (N = 247) 17 of 72 (23.6) 20 of 175 (11.4) 0.025
Self-rated health compared to one year ago (worse) (N = 246) 39 of 71 (54.9) 46 of 175 (26.3) <0.001
Sense of security (insecure) (N = 246) 17 of 73 (23.3) 25 of 173 (14.5) 0.134
Perceived loneliness (N = 241) 47 of 71 (66.2) 52 of 170 (30.6) <0.001
GDS-15 score ≥5 (indicating depression) (N = 187) 15 of 59 (25.4) 2 of 128 (1.6) <0.001
PGCMS score ≥13 (indicating high morale) (N = 221) 18 of 68 (26.5) 91 of 153 (59.5) <0.001
MMSE score* (N = 243) 72 (26.5 ± 3.8) 171 (26.4 ± 3.5) 0.900
I-ADL (dependent)* (N = 247) 36 of 75 (48.0) 87 of 172 (50.6) 0.814
P-ADL (dependent)* (N = 246) 7 of 75 (9.3) 7 of 171 (4.1) 0.134FE
Gait speed (m/s)* (N = 240) 73 (0.7 ± 1.9) 167 (0.7 ± 1.3) 0.819
Hearing (impaired)* (N = 241) 4 of 73 (5.5) 10 of 171 (5.8) 1.000FE

* Data retrieved from the SilverMONICA study (2016–2019).

Percentages are reported for dichotomous variables, while continuous variables are presented as mean ± standard deviation. Bold type indicates significant values (p < 0.05). Dichotomous variables were analysed using the χ2 test for independence (with Yates’ continuity correction), while continuous variables were analysed using an independent-samples t-test.

FE Fisher’s exact test was applied in place of the χ2 test for independence if >20% of cells had an expected cell count <5, and no expected cell count <1.

GDS-15: Geriatric Depression Scale 15-item version; PGCMS: Philadelphia Geriatric Center Morale Scale; MMSE: Mini-Mental State Examination; I-ADL: instrumental activities of daily living; P-ADL: personal activities of daily living.

Only 4 out of 77 participants in the COVID-19 follow-up sample stated that they had had the COVID-19 infection. Due to the high number of participants not answering whether they had had COVID-19, approximately 15% of the participant’s medical records were reviewed concerning positive COVID-19 test results. Of 37 participants with their medical records reviewed, only one had had a positive COVID-19 test.

3.4 Social factors

Social factors associated with the negative impact on mental health by COVID-19 were difficulty following social distancing recommendations, negative subjective impact on social situation by COVID-19, and reduced number of physical contacts (Table 3). The participants reduced their physical contacts with all parts of their social network (family, relatives, friends, neighbours, and others). There was a substantial reduction in reported contacts with other groups of people, ranging from 42.4% up to 84.1%. Those with negative impact on mental health by COVID-19 reduced their contacts more, but not significantly more than those without a negative impact. Only when combining one or more of the parts of their social network there was a significant difference (p-value 0.034). Further, there was an larger increase in non-physical contacts among those with negative impact by COVID-19 compare to those without, however it was not significantly larger.

Table 3. Association between social factors and mental health during the COVID-19 pandemic (N = 250).

Negative impact on mental health by COVID-19
Yes (N = 75) No (N = 175)
n (%) n (%) p
Difficulty adhering to social distancing recommendations (N = 244) 23 of 73 (31.5) 12 of 171 (7.0) <0.001
Subjective impact on social situation by COVID-19 (negative) 68 of 75 (90.7) 116 of 173 (67.1) <0.001
Experience of not receiving the required amount of help (N = 185) 3 of 57 (5.3) 6 of 128 (4.7) 1.000FE
Regular visits from home help services (N = 248) 18 of 74 (24.3) 39 of 174 (22.4) 0.871
Frequency of physical contacts (lower)
    • One or more social networks (N = 221) 68 of 68 (100.0) 143 of 153 (93.5) 0.034 FE
    • Family members (N = 248) 61 of 75 (81.3) 122 of 173 (70.5) 0.105
    • Relatives (N = 241) 61 of 74 (82.4) 116 of 167 (69.5) 0.052
    • Friends (N = 242) 59 of 74 (79.7) 121 of 168 (72.0) 0.269
    • Neighbours (N = 243) 41 of 73 (56.2) 72 of 170 (42.4) 0.066
    • People not otherwise specified (N = 231) 58 of 69 (84.1) 123 of 162 (75.9) 0.230
Frequency of non-physical contacts (higher)
    • One or more social networks (N = 206) 44 of 63 (69.8) 85 of 143 (59.4) 0.206
    • Family members (N = 239) 43 of 72 (59.7) 83 of 167 (49.7) 0.200
    • Relatives (N = 239) 34 of 74 (45.9) 58 of 165 (35.2) 0.149
    • Friends (N = 235) 32 of 72 (44.4) 58 of 163 (35.6) 0.253
    • Neighbours (N = 233) 8 of 72 (11.1) 18 of 161 (11.2) 1.000
    • People not otherwise specified (N = 212) 11 of 65 (16.9) 13 of 147(8.8) 0.140

Percentages are reported for dichotomous variables. Bold type indicates significant values (p < 0.05). Dichotomous variables were analysed using the χ2 test for independence.

FE Fisher’s exact test was applied in place of the χ2 test for independence if >20% of cells had an expected cell count <5, and no expected cell count <1.

3.5 Predictors of decline in mental health

The strongest predictor for reported decline in mental health by COVID-19 was difficulty adhering to social distancing recommendations (Table 4). Other predictors were perceived loneliness, subjective impact on the social situation by COVID-19, high educational level, and self-rated health compared with one year ago. High morale, according to the PGCMS score, was associated with less decline in mental health. Sex and dependence in P-ADL did not associate with a decline in mental health.

Table 4. Logistic regression analysing factors associated with a decline in mental health during the COVID-19 pandemic.

95% CI for OR
p OR Lower Upper
Sociodemographic factors
    Sex (female) 0.797 1.10 0.53 2.28
    Educational level (high)* 0.037 2.32 1.05 5.12
Health-related factors
    Self-rated health compared to one year ago (worse) 0.045 2.17 1.02 4.62
    Perceived loneliness <0.001 3.87 1.83 8.17
    PGCMS score ≥13 (indicating high morale) 0.014 0.37 0.17 0.82
    P-ADL (dependent)* 0.736 1.30 0.29 5.91
Social factors
    Subjective impact on social situation by COVID-19 (negative) 0.012 3.74 1.34 10.48
    Difficulty adhering to social distancing recommendations 0.001 5.10 1.92 13.53

* Data retrieved from the SilverMONICA study (2016–2019).

Model performance in test sample (N = 226)

Hosmer and Lemeshow goodness-of-fit test: χ2 = 3.810, df = 8, p = 0.874 (indicating support for the model)

Nagelkerke R2 (pseudo-R2): 0.405

Bold type indicates significant values (p < 0.05). OR: odds ratio; CI: confidence interval; COVID-19: coronavirus disease 2019; P-ADL: personal activities of daily living; df: degrees of freedom.

4. Discussion

This study shows that 30% of the very old participants experienced that the COVID-19 pandemic had negatively affected their mental health. Both social and health-related factors were independently associated with a decline in mental health.

The explanation for why 30% of study participants reported a negative impact on mental health by the COVID-19 pandemic is most likely multifactorial, including intra-individual, inter-individual, societal, and cultural aspects. The seemingly low frequency of COVID-19 infections in the sample suggests that the negative impact on mental health is mainly an indirect effect, such as social distancing, and not directly caused by COVID-19 itself or the post-COVID syndrome.

The three factors with the highest odds ratio of negative impact on mental health by the COVID-19 pandemic in our final logistic regression model were all related to social factors. The three factors were: Difficulty adhering to social distancing recommendations, perceived loneliness and feeling that the social situation was negatively impacted by the COVID-19 pandemic. They will be further discussed below.

First, when asked whether the participants had found it difficult to follow restrictive measures recommended by the Public Health Agency, respondents who reported difficulty adhering to these recommendations had a higher risk for a decline in mental health in our logistic regression model. The multifaceted nature of this finding should be considered, encompassing cognitive (i.e., difficulty accessing and understanding recommendations) and social (i.e., difficulty being away from family and loved ones) dimensions. In a previous study by Gustavsson et al. [17], 88.5% of participants found recommendations from government authorities in Sweden to be clear and concise, thus supporting the particular importance of the social aspect of the question (i.e., difficulty being away from loved ones). Mean MMSE scores and educational status did not differ between our groups, supporting the lesser importance of cognitive aspects. Conclusions should be made with caution, though, as the MMSE scores are from the SilverMONICA baseline and, therefore, a few years old. There are many possible reasons why some individuals could find it difficult to follow social distancing recommendations. One feasible explanatory model is inadequate coping strategies when facing difficulties. Previous studies have found that adaptive coping strategies such as positive thinking, active stress coping, and social support are significant predictors of better mental health in a pandemic setting [33, 34], thus supporting the promotion of such adaptive coping strategies as a preventive measure during future pandemics. Worth noting is another study that after the Swedish Public Health Agency issued the non-mandatory recommendations to avoid crowded places found a sharp drop in visits to overcrowded places for 70-year-olds, which also resulted in a decline in severe COVID-19 cases for the same age-group [35].

Second, perceived loneliness was associated with a negative impact on mental health. This association between perceived loneliness and mental health is consistent with international results during the beginning of the COVID-19 pandemic [8, 3638]. Interestingly, both those with negative impact on mental health and those without reduced their physical contact. Further, no significant association was found between residential status (living alone versus living with someone) and impact on mental health. Developing effective interventions for loneliness has proven more difficult. Though there might be no simple solution, researchers have found that engagement of older adults in social groups and communities reduces loneliness and its adverse effects [3941] which is particularly difficult to implement during a pandemic.

Third, negative impact on their social situation was also reported significantly more among those with a negative impact on mental health from COVID-19 compared to those without. Similar results have been found by other authors [42, 43]. To further explore this we asked the participants about changes in frequency of their contacts with other people and there were reduction in physical contacts and an increase in non-physical contacts but there were hardly any differences between those who reported a negative impact on mental health by COVID-19 compared to those without a negative impact. This could be due to the sample size, how the questions were stated or that there were no difference. Finally, worth mentioning are the four participants who indicated a positive impact by COVID-19 pandemic on their mental health. This small group is interesting, however too small for statistical testing and in all our statistical calculations they were therefore combined with those who reported no impact on mental health by COVID-19. We can only speculate on the reasons for the positive impact on mental health from social distancing measures during COVID-19, but perhaps the participant had unwanted social contacts before COVID-19 that they now had an excuse to withdraw from.

Another important factor for mental health during COVID-19 pandemic could be health aspects, particularly psychiatric health issues. The prevalence of GDS-15 scores indicative of depression was only 9.1% in the total sample. This is lower than previous results, with studies reporting prevalence of depression during the COVID-19 pandemic ranging from 22.2% to 46.4% [17, 44, 45]. This could partly be explained by differences in data collection, measuring scales, and age of participants and may limit the comparability of study results. However, among respondents reporting a negative impact on mental health by the COVID-19 pandemic, 25.4% had GDS-15 scores indicative of depression.

A previous study by Ausín et al. suggested that women experienced more depression, anxiety, and loneliness during the COVID-19 pandemic [46]. However, the present study found no significant association between women and negative mental health impacts. Possible explanations may be our selection of participants in the study, lack of power or because the study only examined very old individuals.

High morale was associated with a positive or no impact on mental health. There may be various reasons for this; one possible explanation is that high morale is a mental resilience factor, as seen by other authors with other mental resilience factors [47, 48]. Our findings indicate that promoting morale may be beneficial during future pandemics.

Surprisingly, high educational level was associated with a decline in mental health in the binary logistic regression model. Explanations can only be speculative: it is possible that these individuals are more dependent on social interactions, have a higher demand for cultural events that were withheld from them, or that they are more susceptible to negative mental health impacts from pandemics. The opposite result was seen in a younger sample by Creese et al. [8].

Since this study showed that a relatively high percentage of older adults had a reduction in mental health due to social distancing, the implication of this study is that efforts must be taken in future pandemics to identify individuals at risk and reduce their suffering. A program to reduce the mental consequences probably needs to be multifactorial, where this study identified at least some important health-related and social factors.

4.6 Strengths and limitations

A particular strength of this study is that the participants were very old: all participants were over 80. Even though this specific age group is at higher risk of contracting the serious disease and subsequently the most targeted by distancing measures, the coverage of very old individuals has been limited in previous studies. Structured telephone interviews, with the possibility of requesting and providing clarification, provided additional information not necessarily available through questionnaires or registry-based studies. The availability of SilverMONICA baseline data allowed the use of complementary data that were not accessible through telephone interviews. Another strength of this study was the high participation rate (65.2%).

However, a few points need to be considered when interpreting our results. First, the question used to assess the possible impact on mental health by the COVID-19 pandemic has not been previously validated. Using a one-question indicator to assess mental state is common and can be effective [49]; however, a set of questions would probably better capture the essence and enable a more fine-tuned cut-off for a decline in mental health. Still, a few factors support the claim of a decline in mental health, such as the changes in self-rated health and sense of security as well as the higher prevalence of depressive symptoms and perceived loneliness among respondents stating a negative impact on mental health by COVID-19. Further, dichotomizing questions with multiple answer alternatives, might lead to the loss of some information and precision [50].

There are some possible biases in this study. One is volunteer bias since only participants were willing to participate in MONICA, SilverMONICA, and this follow-up survey constituted the final research sample. When studying individuals 80 years old or older, survival bias also needs to be acknowledged. Finally, the subject’s ability to participate in this follow-up study was influenced by hearing capability as well as cognitive ability, and this selected the healthier individuals.

The study’s cross-sectional design limits claims regarding causality. Some data were collected in 2016–2019 (the SilverMONICA baseline); hence, these data should be interpreted with reservations, given possible changes since then.

Another aspect to consider is the changes in the epidemic situation during data collection. At the beginning of the study, Sweden was in the middle of its second wave of COVID-19. Infection rates were high, especially among individuals living in retirement homes or receiving home help services [51]. Vaccination against COVID-19 had been initiated, with residents of long-term care facilities, healthcare workers, and older adults being prioritised [52]. In contrast, at the end of data collection, Sweden was at the end of its second wave of COVID-19, infection rates were decreasing, and many study subjects had already received their first vaccination.

4.7 Conclusion

A relatively high percentage of very old people had a negative impact on mental health from social distancing related to the COVID-19 pandemic. The cause is probably multifactorial, and this study showed that factors such as perceived loneliness and difficulty adhering to social distancing measures are important. Still, also resilience factors such as high morale seemed to be protective. These factors are important if future pandemics’ negative impact on mental health for older people from future pandemics should be prevented.

Acknowledgments

We are thankful to all participants in the SilverMONICA study, who devoted many hours to the baseline examination and this follow-up. We thank Ronja Messmer and Anna Olofsson for performing the interviews. Anna Olofsson, together with Mirjam Söderberg prepared the dataset, and Robert Lundqvist contributed statistical analyses. Lastly, we thank all the researchers and research assistants involved in SilverMONICA and the SilverMONICA follow-up survey, as well as the Biobank Research Unit at Umeå University.

Data Availability

Data are available from the The Biobank Research Unit, Umeå university, for researchers who meet the criteria for access to confidential data and have approval from Ethics Committee. More information can be found here: https://www.umu.se/en/biobank-research-unit/research/access-to-samples-and-data/ Please contact the Biobank Research Unit before writing the application for ethical approval: asa.agren@umu.se.

Funding Statement

The SilverMONICA study was funded by FORTE, the Swedish Research Council for health, working life and welfare (2016-01074); the County Councils in Norrbotten and Västerbotten (Visare Norr and ALF); the Borgerskapet in Umeå Research Foundation; the Swedish Dementia Association; the Ragnhild and Einar Lundström Memorial Fund; the Erik and Anne-Marie Detlof Research Foundation; the Swedish Society of Medicine; Thuréus; the Strategic Research Program in Care Sciences (SFO-V, Sweden); and the King Gustaf V and Queen Victoria’s Foundation of Freemasons. The COVID-19 follow-up was supported by Umeå University. The funders had no role in the study design, data collection and analyses, decision on whether to publish or preparation of this manuscript.

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25 Jul 2023

PONE-D-22-23481Home alone: association between the COVID-19 pandemic and mental health in very old peoplePLOS ONE

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Reviewer #1: This manuscript is significant and relevant to the current post-Covid scenario, where it is trying to find the relationship between mental health and social distancing, also relate it to multivariable like sex, education level, and place of residence. The study is mainly about the oldest old population who were more severely, and in Sweden, the COVID-19 social distancing norms were primarily focused on the aged people (above 70 years). The author analyzed that only 30% support a negative impact on mental health. In contrast, a larger group of around 70% supports no or positive effects on mental health and relates it with high morale. This point need a more clarification.

The Title of the manuscript is concise and gives a clear idea about the whole manuscript.

The abstract summarizes well with well-defined sections like background, methods, results, and conclusion. There is enough information to make readers understand immediately, though here, the author might have a check on the repetition of data (30%) in results and conclusion.

The introduction gives a brief background and contemporary scenario related to this study. Appreciate the data retrieved from the World Health Organization about the number of confirmed COVID cases and death; the author might add the date when it has been retrieved. This study has been related to the survey and has appropriate research objectives, which can be more elaborate.

The method section is clear, well describes sources, ethical consent, interview details, and sample size. The author could clarify the use of different scales to avoid confusion. Here in part 2.5.4, the author well classifies the variable into physical contacts and non-physical contacts. However, the word social distancing could be defined briefly to avoid confusion.

The result presented goes the same with the purpose and method of the study. The tables added were clear. The source of data written by the author is Silver MONICA (2016-19); there needs to be clarity on whether the data source is the mentioned one or the follow-up study Silver MONICA COVID-19.

The discussion sections were the findings were well supported by the relevant work done with COVID-19 and mental health. The author aims to relate the result; however, the work is more specifically supported based on European countries. The author might refer to https://doi.org/10.1093/eurpub/ckac101, which analyzes the Swedish government's positive impact of age-specific non-mandatory norms. And there is an alternate use of females and women in the seventh paragraph of this section if the author could clarify the reason behind this.

Acknowledging the effort for mentioning the strength and limitations, which is very realistic, like biases and self-reported data. The author needs to include the implication of this study.

However, the conclusion needs a significant revision. It should be expanded and elaborative with the study's findings and future scope.

Reviewer #2: “Home alone: association between the COVID-19 pandemic and mental health in very old people”

CONTENT OF THE REVIEW

Identifying features

Title of chapter and authors: Home alone: association between the COVID-19 pandemic and mental health in very old people

General observation:

Manuscript is partially sufficient to look over the research objective. Even study also fail to capture previous research related to mental health and home alone. Discussion part also suffer with contemporary discourses and related facts.

Statistical part is partially fulfilling the scientific analysis criteria. Association between variable and data size in row and column is not statistically corrected. It is applicable for table 1, table 2, and table 3. Binary logistic method also needs to be crosschecked. Finding in table 4 is doubtful. please check again and see the value of odd ratio and corresponding interval value.

Data is not available publicly, so it is matter of ethical approval from concern body. The author has ethical approval for data source.

Manuscript has gone through various incorrect sentences and wrong sentence frame; Manuscript needs a lot of rigorous grammatical check.

Abstract

The paper has a lot of problems with grammar that start right at the beginning. See “Of 394 eligible participants, 257 (65.2%) agreed to participate. Of these, 250 32 individuals reported mental health impact from COVID-19 and constituted the final sample”.

In result section under abstract, it is not good to write detailed finding of odds ratio.

Please revise the text with better sentence structure and clarity and make it concise.

Introduction

The current text exhibits a deficiency in connectivity and coherence both within individual sections and across different sections. There is a need to establish a connection between the two units. The authors should incorporate relevant scholarly sources from previous studies. The introduction fails to effectively convey the essence of the title. The topic of mental health is noticeably lacking in the section on being home alone. The manuscript, to some extent, did not successfully convey the essence of the concept of being home alone. The precise definition of study is not provided. Similar to this, literature on mental health has failed to show any correlation with numerous cofactors from earlier research conducted within a country or around the world.

Data and Methodology

The manuscript tries to include information from both the SilverMONICA study and the follow-up study. The authors missed the opportunity to do the appropriate amount of analyzing the data. 250 people filled out the survey (line 103), but the numbers in Table 1, Table 2, and Table 3 do not match up in the rows and columns where they should. If the row data is 247, how is it split between columns 75 and 175? And it is also applicable for other numbers in row.

The subjective response is grouped together under the health-related factor. Does the author have any studies that show how to combine subjective responses with five groups into two? Please provide appropriate references. Similarly, “Self-rated health compared to one year ago was based on the SF-36 item “compared to one year 138 ago, how would you rate your health in general now” and responses are 0 = secure, 1 = insecure/hard to tell. Do author has any reference to club the category (insecure and hard to tell). Do author has any reference to club the category (insecure and hard to tell). Again, in reference to Geriatric Depression Scale, Philadelphia Geriatric Center Morale Scale Mini-Mental State Examination, how author decided the limit of score for particular case or event. Author does not provide any depth information related to score construction and related questions. Also, the variable under "social factor" is not enough to explain why the categories of responses might be merged.

It is also good to capture only relevant scale or score instead of multiple scale or score, and before that detailed and proper justification need to be address.

Results

Table 1 consist of association of sample data i.e., 250 and they have answered the related question. This sample is again classified in Yes (N = 75) and No (N = 175). But when it associated with educational status (years of schooling) * (N = 247), Educational level (high)* (N=247), Place of residence (number of inhabitants) * (N = 239), and Residential status (residing alone) * (N = 244), these sample is not matched with column sample. It is again applicable for table 2 and table 3. It requires further analysis of data. In table 4 logistic regression was perform for various Sociodemographic factors, Health-related factors, and social factors. It seems that data analysis does not perform well. Odd ratio with lower and upper limit explains different story. I recommend for further analysis. The author again highlighted various score and scale for mental health, but manuscript does not consider such information and calculating method of that score. GDS-15 score and MMSE score do not capture in multivariate analysis. Author should provide an analysis or information-why they are excluded from the analysis how it can be identified without any findings (Any variable with a univariate p-value of <0.15 was selected as a candidate for the multivariable analysis. LINE:213)

Majorly all the tables have numerous findings, but author should interpret it under different section. It is missing in manuscript.

Why chi2 test and FE fisher test used together? it is good to relay on specific method for all the variables.

Discussion

In this section author used “very old”. Is it previously described in manuscript anywhere. Please refer it. Is 30 percent or any number is directly associated with table 1. line 309 to 313 is not evidence-based statement. Kindly refer it with previous research. Please explain line 325 with various associated factor comes under GDS-15. The line “This could partly be explained by differences in data collection, measuring scales, and age of participants and may limit the comparability of study results. However, amongst respondents reporting a negative impact on mental health by the 330 COVID-19 pandemics,” could be the part of limitation of study

Logistic regression model seems incorrectly estimated please check again. Even in discussion section odds value should be the part of discussion but it is missed majorly. Please refer standard form of odds ratio, p value, lower limit and upper limit during framing the statement.

Overall, this manuscript needs a lot of regress work under following section-

• Previous research and key definition of objective term

• Grammatical error and sentence framing

• Data cleaning and required variable.

• Data analysis and interpretation of findings

• Discussion and logical statement.

**********

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Reviewer #2: No

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PLoS One. 2024 Apr 2;19(4):e0299098. doi: 10.1371/journal.pone.0299098.r002

Author response to Decision Letter 0


25 Aug 2023

Response to Editor and Reviewers

We thank the reviewers for their time and effort in reviewing our manuscript. Please find our response below, where reviewers’ comments have been slightly shortened.

Editor

1. The style has been updated to better adhere to PLOS ONE style requirements.

2. In the ethics section, “Signed consent” has now been changed to “Written consent”.

3. Funding section has been corrected.

Reviewer #1

1. The author analyzed that only 30% support a negative impact on mental health. In contrast, a larger group of around 70% supports no or positive effects on mental health and relates it with high morale. This point need a more clarification.

Thank you for this; however, we are a little bit uncertain how to clarify this. We hope the newly added implication and conclusion give the clarification needed.

2. The abstract gives enough information to make readers understand immediately, though here, the author might have a check on the repetition of data (30%) in results and conclusion.

We appreciate that you pointed out this repetition. We have now changed the conclusion in the abstract to (line 51-53)

“A high percentage of very old people reported a negative impact on mental health from the COVID-19 pandemic, primarily from loneliness and difficulty adhering to social distancing measures, while high morale seemed to be a protective factor.

3. The introduction data retrieved from the World Health Organization about the number of confirmed COVID cases and death; the author might add the date when it has been retrieved.

Thank you for noticing. For unknown reasons, this information disappeared. The access date is now visible in reference number one (cited 2022-05-30), line 548.

4. Research objectives can be more elaborate.

Thank you for pointing out this. The research question is now extended:

“The purpose of this study was to investigate the impact the COVID-19 pandemic had on older peoples’ mental health and factors associated with a decline in mental health.”, line 103-104.

5. In the method section, the author could clarify the use of different scales to avoid confusion.

We fail to understand the reviewer’s concern. We have reported all scales used in our study. One for assessing depressive symptoms (GDS-15), one for morale (PGCMS), one for cognition (MMSE) and so on.

6. The word social distancing could be defined briefly to avoid confusion.

A definition of social distancing has now been added:

“Social distancing in this study was defined as avoiding crowded places, avoiding social contacts outside the family or persons in your household and keeping a longer physical distance from other people if crowded places had to be visited.”, line 274-276.

7. There needs to be clarity on whether the data source is the mentioned one or the follow-up study Silver MONICA COVID-19 in the Results section.

Thank you for pointing out this. We have added words to clarify where the data came from, please see the revised manuscript, especially Result sections 3.1 to 3.3.

Some data from the original SilverMONICA study (2016-2019) we believed was unproblematic, for instance, years in school. Other data might have changed, for example, MMSE and ADL-status, but we thought it provided some information rather than not using them. New data was difficult to get over the telephone during the pandemic.

8. The author might refer to https://doi.org/10.1093/eurpub/ckac101, which analyzes the Swedish government's positive impact of age-specific non-mandatory norms.

Thank you for the recommendation. The reference was added in the Discussion section, line 408-415 and 678-680.

9. And there is an alternate use of females and women in the seventh paragraph of this section if the author could clarify the reason behind this.

Thank you for pointing this out. We have changed the wording to:

“A previous study by Ausín et al. suggested that women experienced more depression, anxiety, and loneliness during the COVID-19 pandemic (43). However, the present study found no significant association between women and negative mental health impacts”, line 425-426.

10. The author needs to include the implication of this study.

We agree and have added the following paragraph at the end of the Discussion: “Since this study showed that a relatively high percentage of older adults had a reduction in mental health due to social distancing, the implication of this study is that efforts must be taken in future pandemics to identify individuals at risk and reduce their suffering. A program to reduce the mental consequences probably needs to be multifactorial, where this study identified at least some important health-related and social factors.“, line 435-439.

11. The conclusion needs a significant revision. It should be expanded and elaborative with the study's findings and future scope.

Once again, we agree and have changed the wording to:

“A relatively high percentage of very old people had a negative impact on mental health from social distancing related to the COVID-19 pandemic. The cause is probably multifactorial, and this study showed that factors such as perceived loneliness and difficulty adhering to social distancing measures are important. Still, also resilience factors such as high morale seemed to be protective. These factors are important if future pandemics' negative impact on mental health for older people should be prevented.”, line 506-511.

Reviewer #2:

1. Study fail to capture previous research related to mental health suffer with contemporary discourses and related facts

Thank you for your opinion. We kindly disagree. We believe that this journal and this article benefit from a short introduction and that we have presented the necessary background material from previous research. If there are specific references we have missed, please point them out or in a specific direction of what is missing.

2. Association between variable and data size in row and column is not statistically corrected. It is applicable for table 1, table 2, and table 3. Binary logistic method also needs to be crosschecked. Finding in table 4 is doubtful. please check again and see the value of odd ratio and corresponding interval value.

We thank you for this, but we don’t understand the problem. The tables are not row-total, they are column-total, for instance in Table 1, where the percentage of females in the two groups does not add up to 100% (64.0% and 49.7%), but this is because there were, for instance, 64.0% female in the group with a negative impact on mental health (47 participants of 75 participants is 64.0%).

3. Manuscript has gone through various incorrect sentences and wrong sentence frame; Manuscript needs a lot of rigorous grammatical check.

The manuscript was sent to a well-known and very competent proofreading company (San Francisco Edit). We have read the manuscript once again and made a few minor corrections.

4. Abstract: The paper has a lot of problems with grammar that start right at the beginning. See “Of 394 eligible participants, 257 (65.2%) agreed to participate. Of these, 250 individuals reported mental health impact from COVID-19 and constituted the final sample”.

We don’t understand why there is concerns about this sentence. This sentence was approved by the proofreading firm. We have shortened it slightly due to wordcount limit after other changes in abstract.

5. Abstract: In result section under abstract, it is not good to write detailed finding of odds ratio. Please revise the text with better sentence structure and clarity and make it concise.

Thank you for your opinion, but we kindly disagree. We believe the abstract should include a few details of the main finding, including the odds ratio to support argument in the conclusion.

6. Introduction: The current text exhibits a deficiency in connectivity and coherence both within individual sections and across different sections. There is a need to establish a connection between the two units.

Thank you for your opinion. We kindly disagree. We believe there is coherence and connectivity between different sections in the manuscript.

7. The authors should incorporate relevant scholarly sources from previous studies. The introduction fails to effectively convey the essence of the title. The topic of mental health is noticeably lacking in the section on being home alone. The manuscript, to some extent, did not successfully convey the essence of the concept of being home alone. The precise definition of study is not provided.

We agree that “Home alone” is a misleading part of the title and has now been removed, line 3. Further, introductions can be written in different ways depending on the journal, some very long and some short. We believe that this journal and this article benefit from a short introduction and that we have presented the necessary background material from previous research.

8. Data and Methodology: 250 people filled out the survey (line 103), but the numbers in Table 1, Table 2, and Table 3 do not match up in the rows and columns where they should. If the row data is 247, how is it split between columns 75 and 175? And it is also applicable for other numbers in row.

In every study, even the best researchers fail to capture all data, and there will be missing data. We have been transparent with this and added the numbers of individuals where data was missing. For instance, in Table 1, years of schooling was only 247 participants out of 250, and there were 74 out of 75 with data among those with negative impact, and 173 out of 175 with data. We did calculations with the data we had. If the reader wants to know the exact numbers, it could be calculated from the percentage. We chose to do this since including every number would make these table very hard to read. In our experience, this is how this matter is most often handled.

9. The subjective response is grouped together under the health-related factor. Does the author have any studies that show how to combine subjective responses with five groups into two?

We believe it is common practice to handle different scales with multiple answering alternatives to make it easier to use in statistics, therefore we did not provide references to grouping of answer alternatives to each scale used in this manuscript. How the five answer alternatives are combined into two might differ on the purpose of the calculations and the distribution of answers. There will be a loss of precision, but it seems reasonable for this type of manuscript.

10. Similarly, “Self-rated health compared to one year ago was based on the SF-36 item “compared to one year ago, how would you rate your health in general now” and responses are 0 = secure, 1 = insecure/hard to tell. Do author has any reference to club the category (insecure and hard to tell).

Please refer to previous answer, number 9. We have provided a justification for grouping “hard to tell” with those who felt insecure. We thank you for pointing our attention to this, since we had an illogical reasoning. It has now been changed to:

“The justification that individuals who stated that it was hard to tell whether they felt secure or not could not, likely were insecure.”, line 184.

11. Again, in reference to Geriatric Depression Scale, Philadelphia Geriatric Center Morale Scale Mini-Mental State Examination, how author decided the limit of score for particular case or event. Author does not provide any depth information related to score construction and related questions.

The cut off for the Geriatric Depression Scale is 5 or more points, which is stated in line 153. We believed we didn’t have to restate the reference 23 – 24.

The PGCM scale was constructed by Lawton in 1972, and in the year 2003, he provided instructions on how to group the scores (in line 160-161) in the following reference already was provided:

Reference 26: Lawton MP. Lawton's PGC Morale Scale [Internet]. Polisher Research Institute Abramson Center for Jewish Life (formerly the Philadelphia Geriatric Center); 2003 [cited 2022-05-30]. Available from: https://abramsonseniorcare.org/media/1198/lawtons-pgc-moral-scale.pdf.

12. Also, the variable under "social factor" is not enough to explain why the categories of responses might be merged.

Please see our response to question number 9

13. It is also good to capture only relevant scale or score instead of multiple scale or score, and before that detailed and proper justification need to be address.

We partially agree and partially disagree with this statement. Too many variables might make it difficult to explain to the reader, and too few will not illustrate the whole picture. We believe the scales in this manuscript are not too many.

14. Results: Table 1 consist of association of sample data i.e., 250 and they have answered the related question. This sample is again classified in Yes (N = 75) and No (N = 175). But when it associated with educational status (years of schooling) * (N = 247), Educational level (high)* (N=247), Place of residence (number of inhabitants) * (N = 239), and Residential status (residing alone) * (N = 244), these sample is not matched with column sample. It is again applicable for table 2 and table 3. It requires further analysis of data.

We apologize, but we don’t understand what the problem is. Please refer to our answers, numbers 2 and 8.

15. In table 4 logistic regression was perform for various Sociodemographic factors, Health-related factors, and social factors. It seems that data analysis does not perform well. Odd ratio with lower and upper limit explains different story. I recommend for further analysis.

We apologize once again we don’t understand what the problem is. Odds ratio presented are between upper and lower limit, and we believe they tell the same story.

16. The author again highlighted various score and scale for mental health, but manuscript does not consider such information and calculating method of that score.

Again, we do not understand the concern.

17. GDS-15 score and MMSE score do not capture in multivariate analysis. Author should provide an analysis or information-why they are excluded from the analysis how it can be identified without any findings (Any variable with a univariate p-value of <0.15 was selected as a candidate for the multivariable analysis. LINE:213)

The MMSE was not included in the final logistic regression model since its p-value, which was 0.90, was above the limit of 0.15 that was necessary to be included.

As mentioned in the statistics section, for statistical reasons we could not include all candidate variables but had to limit the variables added in the final model. Rule of thumb is that you can use one variable per 10 participants with the investigated outcome and since we had 75 participants with negative impact on mental health, we could use 7 or 8 variables in our regression model, which is stated in the manuscript. From previous knowledge we know that GDS-15 (i.e depression) correlate strongly with perceived loneliness, and there were fewer who had depressive symptoms than had perceived loneliness, we therefore chose only to use perceived loneliness in the final regression model.

18. Majorly all the tables have numerous findings, but author should interpret it under different section. It is missing in manuscript.

We are of the opinion that important results should be interpreted in the discussion section, but it would be tedious for the reader if every result was discussed. Please also see our answer to concern number 25.

19. Why chi2 test and FE fisher test used together? it is good to relay on specific method for all the variables.

Both tests are used to analyze dichotomized variables. “Chi-square Test for Independence” is the most commonly used, but there are assumptions that need to be fulfilled. One such is that variables should not be skewed, or at least 80% of cells with expected frequencies of 5 or more. If this assumption is violated, then most scientists use the “Fisher's Exact test” (in 2 by 2 tables). This is common practice.

20. Discussion: In this section author used “very old”. Is it previously described in manuscript anywhere. Please refer it.

We don’t understand this concern. Very old is used in the title: “Very old people”. In the first line in the Discussion section, we wrote “very old participants”, and under the design section, we explained how old our sample is (>80 years).

21. Is 30 percent or any number is directly associated with table 1.

We apologize but we don’t understand the concern. We found that 75 individuals experienced negative impact from COVID-19 out of 250 and calculated 75/250=0.30 i.e. 30 percent

22. line 309 to 313 is not evidence-based statement. Kindly refer it with previous research.

We apologize, but we don’t understand the problem. We just state that having difficulty adhering to recommendations from authorities, the problem might have several different reasons, both cognitive and social seems reasonable. We added this statement to help the reader follow our argument through the long paragraph. Since we don’t know the true reasons for the problem why the participants experience problem to adhere to the guidelines we speculate over the reasons. We feel it is impossible and inappropriate in a manuscript like this to have a comprehensive debate on all possible reasons.

23. Please explain line 325 with various associated factor comes under GDS-15. The line “This could partly be explained by differences in data collection, measuring scales, and age of participants and may limit the comparability of study results. However, amongst respondents reporting a negative impact on mental health by the 330 COVID-19 pandemics,” could be the part of limitation of study.

We apologize, but we don’t understand the concern. We noticed our number of depressions were lower than in other research, but among those who had a negative impact on mental health from COVID-19 the number were similar. We can only speculate on the differences. Since GDS-15 is not included in the final regression model, we did not comment on this in strength and limitations.

24. Logistic regression model seems incorrectly estimated please check again.

We apologize once again, but we don’t understand the concern. We have double-checked all the calculations.

25. Even in discussion section odds value should be the part of discussion but it is missed majorly.

We have been taught not to present data in discussion section, or at least keep it to a minimum. Therefore, we did not present odds values and they were already presented in the Results section.

We chose to discuss the variables with the highest Odds Ratio: perceived loneliness, difficulties in adhering to social distancing, the protective effect of high morale, and most surprisingly, that high educational level was significant. We also chose to discuss some variables not included in the model, such as GDS-15, sex, and residential status. We chose not to discuss all variables (like perceived negative subjective impact on the social situation) because long manuscripts are more difficult to get published.

26. Please refer standard form of odds ratio, p value, lower limit and upper limit during framing the statement.

We believe we have used standard form used by the paper when presenting our results.

27. Overall, this manuscript needs a lot of regress work under following section-

• Previous research and key definition of objective term

• Grammatical error and sentence framing

• Data cleaning and required variable.

• Data analysis and interpretation of findings

• Discussion and logical statement.

Once again, we thank you for your opinion, but we kindly disagree.

Attachment

Submitted filename: Response to Reviewers.docx

pone.0299098.s001.docx (39.9KB, docx)

Decision Letter 1

Alok Ranjan

10 Oct 2023

PONE-D-22-23481R1Association between the COVID-19 pandemic and mental health in very old peoplePLOS ONE

Dear Dr. Niklasson,

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 see the comments made by Reviewer 2 and try to address them as much as possible.

Please submit your revised manuscript by Nov 24 2023 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.

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Academic Editor

PLOS ONE

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: (No Response)

Reviewer #2: (No Response)

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

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: No

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

Reviewer #1: Yes

Reviewer #2: No

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

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

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

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

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6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: The authors of this article have provided clarification on many of the issues I brought up in my earlier review. If authors could address these :-

1.Topic : The authors could be more specific in the topic by stating the nation name, as the study is primarily focused on the context of Sweden.

2. Result : In order to analyse the statistical findings, the commentary of the tables in the result section needs to be expanded, especially section 3.4 - social factors.

Reviewer #2: I am grateful to the author for the response. Despite the fact that these responses cannot provide any valid evidence to support the raised concern. In the majority of cases, the author neither admits the validity nor provides supporting text or evidence. In descriptive statistical analyses where the author fails to identify missing responses, data cleaning is a major concern. I am again emphasizing an important review point (In previous Review) where the author does not cite any evidence-

Point 8- Data and methodology: cleaning of data and study sample.

Point 9, Point 10, and Point 12- Classification of categories under Subjective response and various other grouping categories--no prior research provides.

I-ADL and P-ADL: The author does not provide specific details for these categories.

Point-15: OR, LL, and UL estimates or highly questionable. [(sample mean) - (constant) x (SEM)] to [(sample mean) + (constant) x (SEM)] could be used to determine the Confidence Interval. Therefore, it may be closer to the mean value of CI.

Even in this investigation, the author provides no supporting evidence for the findings.

Even under table 4, section 3.5 Predictors of deteriorating mental health is not adequately discussed in detail.

Overall, the provided manuscript ignores the main correction that was previously communicated to the author. I believe that the manuscript is not suitable for my acceptance.

**********

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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: No

**********

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PLoS One. 2024 Apr 2;19(4):e0299098. doi: 10.1371/journal.pone.0299098.r004

Author response to Decision Letter 1


28 Nov 2023

The second response to Reviewers

We thank once again the reviewers for their time and effort in reviewing our manuscript! Please find our response below.

Reviewer #1

1.Topic: The authors could be more specific in the topic by stating the nation name, as the study is primarily focused on the context of Sweden.

RESPONSE: We are not sure what “topic” refers to, but we have changed the title and aim so that it now states “in Sweden”. We hope this settles the concern.

2. Result: In order to analyze the statistical findings, the commentary of the tables in the result section needs to be expanded, especially section 3.4 - social factors.

RESPONSE: Thank you for pointing our attention to this aspect. We have made changes to section 3.4 in the results and also in parts of the discussion where we added a paragraph, particularly for discussing these findings.

Reviewer #2:

Reviewer #2 ask us to improve the answer to five previous concerns and two new ones, and we are happy to try to make a better answer!

1. Previous point 8 Data and Methodology: 250 people filled out the survey (line 103), but the numbers in Table 1, Table 2, and Table 3 do not match up in the rows and columns where they should. If the row data is 247, how is it split between columns 75 and 175? And it is also applicable for other numbers in row.

Data and methodology: cleaning of data and study sample

RESPONSE: We are still not sure if we have understood your concern correctly, but we have now added information on the denominator in Tables 1, 2, and 3.

For instance: Residential status (residing alone), among those with negative impact on mental health by COVID-19 there were 38 residing alone and 75 were able to answer, and among those without negative impact 79 residing alone of 169. That means that of (38+79=) 117 were residing alone and (75+169=) 244 who were able to answer the question. We now have presented all the values and the reader can make Chi-square calculations if desired to check our numbers.

2. Previous points 9, 10, and 12 Does the author have any studies that show how to combine subjective responses with five groups into two? Do author has any reference to club the category Not enough to explain why the categories of responses might be merged.

RESPONSE: The use of dichotomization has been discussed over many years (1-3). It can be used to simplify data analyses and interpretation and to be able to compare. There are drawbacks such as loss of information, the cut-offs might not be obvious, different cut-offs can lead to different conclusions, decreased precision, etc. We have added to the manuscript a reason for using dichotomization in the method section and in the limitations discussed drawback of such procedure.

There are manuscripts that for instance combine five answer alternatives to two, evaluation of one’s health (4, look in Table 1).

1. Ben-Shakhar G. A further study of the dichotomization theory in detection of information. Psychophysiology. 1977 Jul;14(4):408-3. PMID: 882621.

2. Altman DG, Royston P. The cost of dichotomising continuous variables. BMJ. 2006 May 6;332(7549):1080. PMID: 16675816;

3. Fedorov V, Mannino F, Zhang R. Consequences of dichotomization. Pharm Stat. 2009 Jan-Mar;8(1):50-61. PMID: 18389492.

4. Tak E, Staats P, Van Hespen A, Hopman-Rock M. The effects of an exercise program for older adults with osteoarthritis of the hip. J Rheumatol. 2005 Jun;32(6):1106-13. PMID: 15940775.

3. Previous point 15 OR, LL, and UL estimates or highly questionable. [(sample mean) - (constant) x (SEM)] to [(sample mean) + (constant) x (SEM)] could be used to determine the Confidence Interval. Therefore, it may be closer to the mean value of CI.

RESPONSE: This was a difficult concern for the authors, so we asked for help from an experienced statistician who gave this answer to provide in this response to Reviewer #2:

”As for the comment on how confidence intervals for odds ratios should be calculated, we agree that the suggested expression is correct for coefficients in a linear model. However, since we use odds ratios as is customary in logistic regression, this expression is not correct.”

We therefore conclude that the output generated from SPSS statistical software is accurate.

4. New point 1 I-ADL and P-ADL: The author does not provide specific details for these categories.

RESPONSE: We thank the reviewer for this comment and agree that the reader could benefit from knowing the background for I-ADL and P-ADL. The following two sentences were included:

“To be deemed as independent in I-ADL the participants had to be independent in all the following activities: cleaning, shopping, transport, and cooking. To be deemed independent in P-ADL, the participants had to be independent in all the following activities: bathing, dressing, toileting, transfer, continence, and eating.”

5. New point 2 Even under table 4, section 3.5 Predictors of deteriorating mental health is not adequately discussed in detail.

RESPONSE: Thank you for pointing our attention to this aspect. We have made changes to section 3.4 in the results and also in parts of the discussion where we added a paragraph, particularly for discussing these findings.

Attachment

Submitted filename: Response to Reviewers2.docx

pone.0299098.s002.docx (25.3KB, docx)

Decision Letter 2

Mario Ulises Pérez-Zepeda

6 Feb 2024

Association between the COVID-19 pandemic and mental health in very old people in Sweden

PONE-D-22-23481R2

Dear Dr. Niklasson,

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

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Reviewer #2: All comments have been addressed

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Reviewer #2: Yes

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Reviewer #2: Yes

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Reviewer #2: Yes

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Reviewer #1: This paper is significant as it deals with ageing population and their mental state during pandemic. This will helps to take specific measures for older population in the future.

Reviewer #2: Thanks for incorporating the comments and improve the manuscript. I also apricate your effort to provide citations with your responses.

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Acceptance letter

Mario Ulises Pérez-Zepeda

22 Mar 2024

PONE-D-22-23481R2

PLOS ONE

Dear Dr. Niklasson,

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on behalf of

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Academic Editor

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Associated Data

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

    Supplementary Materials

    Attachment

    Submitted filename: Response to Reviewers.docx

    pone.0299098.s001.docx (39.9KB, docx)
    Attachment

    Submitted filename: Response to Reviewers2.docx

    pone.0299098.s002.docx (25.3KB, docx)

    Data Availability Statement

    Data are available from the The Biobank Research Unit, Umeå university, for researchers who meet the criteria for access to confidential data and have approval from Ethics Committee. More information can be found here: https://www.umu.se/en/biobank-research-unit/research/access-to-samples-and-data/ Please contact the Biobank Research Unit before writing the application for ethical approval: asa.agren@umu.se.


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