Abstract
Background
Malaria remains a leading cause of morbidity and mortality in Nigeria. Artemisinin-based combination therapies (ACTs) are first-line treatments, but adherence is suboptimal and resistance is emerging. This study assessed patterns, determinants and barriers related to antimalarial drug use and adherence in Osun State, southwestern Nigeria.
Methods
A community-based cross-sectional household survey was conducted between October 2024 and September 2025. Using multistage sampling, 1500 residents aged ≥15 years across three senatorial districts were enrolled. Data on sociodemographics, recent antimalarial use, adherence, knowledge and access barriers were collected via structured questionnaires. Descriptive and inferential statistics, including binary logistic regression, were used to identify factors associated with treatment completion.
Results
The mean age of participants was 26.7 (±10.7) years; 77.0% were female. Among 713 recent antimalarial users, 70.5% completed the full course. Persistent chloroquine use was reported by 46.0% of users. Cost (40.5%) was the most cited access barrier. In adjusted analysis, treatment completion was significantly associated with tertiary education (adjusted OR (aOR)=1.85, 95% CI 1.32 to 2.59), urban residence (aOR=1.55, 95% CI 1.10 to 2.18), formal drug sources (aOR=2.20, 95% CI 1.55 to 3.12) and awareness of drug resistance (aOR=1.95, 95% CI 1.42 to 2.68).
Conclusions
Suboptimal adherence, persistent use of discontinued drugs and high out-of-pocket costs threaten malaria control and may accelerate drug resistance. Public health strategies should enforce prescription policies, institute basic universal health coverage to subsidise ACTs, implement behaviour change communication and address drug unavailability in rural areas to mitigate resistance risks.
Keywords: Malaria, Public Health
WHAT IS ALREADY KNOWN ON THIS TOPIC
A significant policy-practice gap exists in malaria treatment in Nigeria, with continued use of obsolete drugs like chloroquine despite official withdrawal.
Suboptimal adherence to recommended artemisinin-based combination therapies (ACTs) is a widespread challenge in sub-Saharan Africa, driven by factors such as cost and lack of awareness.
Financial barriers and reliance on informal drug sources are major impediments to effective malaria case management in Nigeria.
WHAT THIS STUDY ADDS
This community-based study quantifies a high prevalence of chloroquine use (46% among recent users) in Osun State, Southwestern Nigeria, nearly two decades after its policy withdrawal.
It identifies specific, modifiable determinants of ACT adherence, including education level, place of residence, drug source and awareness of resistance, which can be targeted by interventions.
The study highlights cost as the predominant access barrier, reported by 64.3% of non-adherent individuals, underscoring the urgent need for financial protection mechanisms.
HOW THIS STUDY MIGHT AFFECT RESEARCH, PRACTICE OR POLICY
The findings call for integrated strategies that combine the formal training and integration of informal drug vendors with stricter regulatory enforcement to phase out non-recommended antimalarials.
Policy should prioritise targeted subsidies or financial support programmes to reduce cost barriers and improve access to quality-assured ACTs, especially for rural and low-income populations.
The evidence supports scaling up focused behaviour change communication campaigns that emphasise the importance of full treatment completion and the threat of drug resistance, tailored to local contexts.
Background
Malaria remains a preeminent global health challenge, with sub-Saharan Africa continuing to bear the highest burden of morbidity and mortality.1 Within this region, Nigeria is disproportionately affected, accounting for approximately one-quarter of all global malaria cases and representing the highest national burden worldwide.2 This enduring crisis occurs within a national context where, despite increased health expenditure, population health outcomes and system coverage lag behind regional peers.3 The transmission of Plasmodium falciparum, the predominant and most lethal species, is sustained by a complex interplay of ecological, socioeconomic and health-system determinants. These include climatic conditions favourable to Anopheles mosquito vectors, widespread poverty, limited and inequitable access to preventive measures and persistent gaps in the quality of malaria case management.4
In response to the rampant spread of resistance to monotherapies like chloroquine (CQ) and sulfadoxine-pyrimethamine (SP), the WHO recommended artemisinin-based combination therapies (ACTs) as the first-line treatment for uncomplicated P. falciparum malaria in 2005.5 Nigeria formally adopted this policy, designating artemether-lumefantrine (AL) as the preferred first-line ACT. The therapeutic rationale for ACTs is robust: the fast-acting artemisinin component rapidly reduces parasite biomass and alleviates symptoms, while the longer-acting partner drug eliminates residual parasites, thereby maximising cure rates and in theory delaying the emergence of resistance.6 This pharmacological strategy was integrated into Nigeria’s National Malaria Strategic Plan, which aims to achieve parasite prevalence of less than 10% by 2025 through case management, mass distribution of insecticide-treated nets (ITNs) and the promotion of intermittent preventive treatment in pregnancy.
However, the long-term efficacy of ACTs is now under severe threat. Artemisinin partial resistance, characterised by delayed parasite clearance following treatment, first emerged in Southeast Asia. Alarmingly, it has now been independently confirmed in multiple countries in East Africa, including Rwanda, Uganda and Tanzania.7 This resistance is primarily mediated by specific mutations in the Pfkelch13 gene.8 The spread of these resistant genotypes in Africa represents a critical juncture for malaria control. Should resistance to the partner drugs also develop and combine with artemisinin resistance, leading to full ACT treatment failure, the public health consequences in high-burden settings like Nigeria could be catastrophic, potentially reversing decades of progress.7
Effective case management, crucial for reducing disease burden, depends not only on drug efficacy but also on correct utilisation. This encompasses timely access to quality-assured medicines, accurate diagnosis and critically strict adherence to the full treatment course. In Nigeria, a significant chasm exists between policy and practice. The persistent use of CQ is a stark illustration. Despite its formal withdrawal from national treatment guidelines over fifteen years ago, CQ remains widely available and commonly used.9 10 This is fuelled by its low cost, historical familiarity and pervasive weaknesses in pharmaceutical regulatory enforcement, particularly within the extensive informal drug market.
Adherence to the full 3-day ACT regimen is frequently suboptimal. Patients often discontinue medication once symptoms abate, a practice driven by the rapid symptomatic relief provided by artemisinins, lack of awareness regarding the importance of completing the course and the economic burden of purchasing the full regimen.11 Incomplete treatment exposes the parasite population to subtherapeutic drug levels, creating a powerful selective pressure for the emergence and spread of resistant strains.12 Furthermore, access barriers are profound and multifaceted. Financial constraints are the most commonly cited barrier, as many Nigerian households face catastrophic out-of-pocket expenditures for malaria treatment, often forcing them to seek care from informal vendors who may stock non-recommended or substandard medicines.13 14
Osun State in southwestern Nigeria exemplifies these national challenges. Under the national strategy, the state implements standard malaria control interventions, including free distribution of ACTs in public health facilities and ITN campaigns. However, significant gaps remain in formal case management and adherence at the community level. The state experiences intense, perennial malaria transmission, with incidence peaking during the rainy seasons—a pattern linked to local climatic factors.15 While possessing a network of health facilities, access equity remains a serious concern, with rural populations facing significant disparities in the availability of quality services and affordable ACTs.16 Previous research in the region has identified gaps in community knowledge regarding appropriate malaria management.17 However, a comprehensive, community-based analysis that concurrently examines patterns of antimalarial use, determinants of adherence and specific access barriers within Osun State is lacking.
This study, therefore, aimed to investigate the patterns and determinants of antimalarial drug use and treatment adherence among residents of Osun State. Specifically, it sought to: (1) quantify the prevalence of ACT use versus obsolete antimalarials; (2) assess the rate of adherence to treatment courses; (3) identify the socioeconomic, geographic and knowledge-related determinants of adherence and (4) characterise the primary barriers to accessing appropriate treatment. The findings are intended to generate actionable, context-specific evidence to inform targeted public health interventions designed to optimise antimalarial use, improve treatment outcomes and help preserve the therapeutic efficacy of ACTs.
Methods
Study design
A community-based cross-sectional survey was conducted to investigate patterns of antimalarial drug use and treatment adherence. The cross-sectional design was selected to capture a representative snapshot of practices and determinants at a single point in time, allowing for the assessment of prevalence and associations between variables. Data collection took place from October 2024 to September 2025 to account for seasonal variations in malaria transmission and healthcare-seeking behaviour.
Study area
The study was conducted in Osun State, southwestern Nigeria, with Osogbo as its capital. The region is characterised by tropical rainforest vegetation, making it an ideal setting for perennial malaria transmission with peak incidence during the wet season.15 17 Under the national strategy, Osun State implements the standard malaria control interventions, including free distribution of ACTs in public health facilities and ITN campaigns. However, significant gaps remain in formal case management and adherence at the community level. The state has a diverse healthcare infrastructure, with varying access to healthcare services, particularly between rural and urban areas.16 Socioeconomic barriers to accessing malaria prevention and treatment, such as the high cost of antimalarial drugs and inadequate healthcare coverage, affect adherence to treatment regimens.14 These challenges, combined with informal drug use and self-medication, contribute to suboptimal malaria treatment outcomes.
Participants and sampling
A multistage sampling approach was used to recruit participants aged 15 years and older. The sample size of 1500 was calculated using a single proportion formula, assuming a 50% prevalence of antimalarial use, a 5% margin of error, and a design effect of 2.0, which yielded approximately 768; this was increased to 1500 to allow for robust stratified analysis across subgroups. In the first stage, three Local Government Areas (LGAs) were randomly selected from each of the three senatorial districts (Osun Central, East and West), based on geographic representation and urban-rural classification. In the second stage, four enumeration areas (EAs) were randomly selected from each LGA from the National Population Commission sampling frame, ensuring balanced urban–rural representation. In the third stage, households were systematically selected within each EA, and one eligible participant was chosen per household. Inclusion criteria included residency in selected EAs for at least 6 months, age 15 years or older, provision of written informed consent and mental competence to answer the questionnaire. For the adherence analysis, participants were included if they reported using an antimalarial within the 14-day recall period, regardless of whether a formal diagnosis preceded the use.
Data collection
A structured, interviewer-administered questionnaire, available in English and Yoruba (the predominant local language), was employed. Enumerators were proficient in both languages to accommodate non-Yoruba speakers. The instrument captured key variables, including sociodemographics, antimalarial use within a 14-day recall period, treatment sources (categorised as formal or informal), self-reported adherence (defined as completion of all doses), knowledge of malaria transmission and drug resistance, and perceived barriers to access. Body temperature was measured by trained field assistants at the time of the interview using digital thermometers (underarm method, 3 min).
Variables and outcomes
The primary outcome was completion of a full antimalarial course among recent users. Independent variables included age, gender, education, income, residence, drug source and knowledge of resistance. General knowledge of malaria transmission was assessed as a contextual indicator of overall malaria awareness to better interpret specific knowledge gaps regarding drug resistance.
Statistical analysis
Data were analysed using IBM SPSS Statistics (V.26.0). Following dual data entry and validation, descriptive statistics were computed. Continuous variables were assessed for normality and are presented as mean (±SD) or median (IQR). Categorical variables are summarised as frequencies and proportions. Bivariate associations between independent variables and the primary outcome, completion of a full antimalarial course among recent users, were examined using Pearson’s chi-square or Fisher’s exact tests, as appropriate. Variables demonstrating an association at p<0.10 in bivariate analyses, alongside covariates of a priori theoretical importance, were entered into a multivariable binary logistic regression model. The model was built using the enter method. Multicollinearity was assessed via variance inflation factors (all <2.5), and goodness-of-fit was evaluated using the Hosmer-Lemeshow test. Results are reported as adjusted ORs (aORs) with 95% CIs. Statistical significance was set at a two-tailed p<0.05.
Patient and public involvement
Patients or the public were not involved in the design, conduct, reporting or dissemination plans of this research. This was a community-based cross-sectional survey where residents participated as study respondents, but there was no formal involvement of patients or the public in the research process beyond their role as participants.
Results
Sociodemographic characteristics
The study included 1500 respondents from Osun State. The mean age was 26.7 years (SD=±10.7). The sample comprised 1155 females (77.0%) and 345 males (23.0%). A majority resided in urban areas (975, 65.0%) and reported tertiary-level education (953, 63.5%). Students constituted the largest occupational group (780, 52.0%). Analysis stratified by treatment outcome revealed significant disparities. Participants who completed a full antimalarial course were significantly more likely to possess tertiary education (75.5% vs 45.2%, p<0.001) and reside in urban settings (73.6% vs 52.4%, p<0.001). Differences in age and gender distribution between completers and non-completers were not statistically significant (online supplemental table 1).
Malaria history and clinical profile
The mean body temperature measured at the time of the survey was 36.79°C (±1.21 SD), reflecting that many participants were asymptomatic or recovering at the time of data collection. Most respondents (765, 51.0%) reported a fever duration of 3–5 days during their recent illness. A recent malaria episode (within 3 months) was reported by 848 participants (56.5%). Clinical factors showed significant associations with adherence. Individuals who completed treatment were more likely to have experienced a recent malaria infection (61.6% vs 50.0%, p=0.004) and to have had a shorter fever duration of 1–2 days (34.8% vs 26.2%, p=0.027) (online supplemental table 2).
Antimalarial use and adherence
Among all participants, 713 (47.5%) reported using an antimalarial drug within the 2 weeks preceding the survey. Of these recent users, 503 (70.5%) reported completing the full recommended treatment course. AL was the most commonly cited antimalarial. However, a substantial proportion of users (46.0%) reported using CQ. The source of medication was a critical determinant of adherence. Procurement from formal sources (hospitals/clinics or pharmacies) was reported for 79.0% of acquisitions and was strongly associated with completion (63.6% of completers versus 38.1% of non-completers sourced from hospitals/clinics, p<0.001) (table 1, online supplemental figure 1).
Table 1. Antimalarial use and sources among recent users (n=713).
| Variable | Category | Total recent users n (%) | Completed treatment (n=503) n (%) | Did not complete treatment (n=210) n (%) | P value |
|---|---|---|---|---|---|
| Completion status | Completed course | 503 (70.5) | – | – | – |
| Did not complete | 210 (29.5) | – | – | – | |
| Drug source | Hospital/clinic | 400 (56.1) | 320 (63.6) | 80 (38.1) | <0.001 |
| Pharmacy | 200 (28.1) | 140 (27.8) | 60 (28.6) | ||
| Self-medication/other | 113 (15.8) | 43 (8.5) | 70 (33.3) |
Access barriers to drugs
Access to antimalarials was severely constrained, with only 20.5% of respondents reporting easy access (online supplemental figure 2). Cost was the predominant barrier, cited by 607 participants (40.5%), followed by distance to a pharmacy (375, 25.0%) and drug unavailability (300, 20.0%). All major barriers were reported significantly more frequently by individuals who did not complete treatment. For instance, cost was a barrier for 64.3% of non-completers compared with 35.8% of completers (p<0.001) (table 2).
Table 2. Barriers to accessing antimalarial drugs, stratified by treatment completion status.
| Barrier | Total sample (N=1500) n (%) |
Completed treatment (n=503) n (%) |
Did not complete treatment (n=210) n (%) |
P value |
|---|---|---|---|---|
| Cost | 607 (40.5) | 180 (35.8) | 135 (64.3) | <0.001 |
| Distance to pharmacy | 375 (25.0) | 95 (18.9) | 85 (40.5) | <0.001 |
| Drug unavailability | 300 (20.0) | 85 (16.9) | 70 (33.3) | <0.001 |
| Lack of information | 155 (10.3) | 40 (8.0) | 45 (21.4) | <0.001 |
| Other | 63 (4.2) | 20 (4.0) | 15 (7.1) |
Knowledge and awareness
General knowledge of malaria transmission was correct in 50.0% of respondents. However, specific awareness regarding antimalarial drug resistance was low (510, 34.0%), and only 375 participants (25.0%) understood the necessity of completing a full treatment course. These knowledge gaps were strongly linked to behaviour. Awareness of drug resistance (46.7% vs 26.2%, p<0.001) and understanding of full-course importance (34.8% vs 19.0%, p<0.001) were significantly higher among those who adhered to treatment (table 3).
Table 3. Knowledge and awareness related to malaria, stratified by treatment completion status.
| Variable | Category | Total sample (N=1500) n (%) |
Completed treatment (n=503) n (%) |
Did not complete treatment (n=210) n (%) |
P value |
|---|---|---|---|---|---|
| Malaria transmission knowledge | Correct | 750 (50.0) | 265 (52.7) | 95 (45.2) | 0.058 |
| Incorrect | 750 (50.0) | 238 (47.3) | 115 (54.8) | ||
| Aware of drug resistance | Yes | 510 (34.0) | 235 (46.7) | 55 (26.2) | <0.001 |
| No | 990 (66.0) | 268 (53.3) | 155 (73.8) | ||
| Understands full course importance | Yes | 375 (25.0) | 175 (34.8) | 40 (19.0) | <0.001 |
| No | 1125 (75.0) | 328 (65.2) | 170 (81.0) |
Factors associated with treatment completion
Multivariable binary logistic regression analysis, controlling for confounding variables, identified four independent predictors of treatment completion among recent users (N=713). Completion was significantly associated with tertiary educational attainment (aOR=1.85, 95% CI 1.32 to 2.59), urban residence (aOR=1.55, 95% CI 1.10 to 2.18), procurement of medicines from formal sources (aOR=2.20, 95% CI 1.55 to 3.12), and awareness of antimalarial drug resistance (aOR=1.95, 95% CI 1.42 to 2.68). Variables including age, gender and income were not significant predictors in the final model (table 4).
Table 4. Logistic regression analysis of factors associated with full treatment completion (N=713).
| Predictor | aOR | 95% CI | P value |
|---|---|---|---|
| Tertiary education | 1.85 | 1.32 to 2.59 | <0.001 |
| Urban residence | 1.55 | 1.10 to 2.18 | 0.012 |
| Formal drug source | 2.20 | 1.55 to 3.12 | <0.001 |
| Aware of resistance | 1.95 | 1.42 to 2.68 | <0.001 |
| Age ≥30 years | 1.22 | 0.89 to 1.68 | 0.214 |
| Female gender | 1.18 | 0.82 to 1.70 | 0.378 |
| Income ≥₦30 000 | 1.25 | 0.90 to 1.74 | 0.184 |
aOR, adjusetd OR.
Discussion
The persistent gap between national malaria treatment policy and community level practice in Nigeria threatens to undermine decades of progress. This study, conducted in Osun State, quantifies critical behavioural and systemic failures, revealing how continued CQ use, suboptimal adherence to ACTs and reliance on informal drug sources collectively create a permissive environment for therapeutic failure and drug resistance.10 These findings necessitate a move beyond documenting problems to implementing integrated, pragmatic public health strategies that address the root causes of these practices.
The finding that 46% of recent antimalarial users reported taking CQ, despite its official withdrawal nearly two decades ago, starkly illustrates a profound policy-practice disconnect. It is crucial to emphasise that this high prevalence of CQ use does not reflect routine formal prescription, as it is strictly against national policy, but rather indicates persistent procurement from informal markets and self-medication. This aligns with evidence that informal drug markets often operate outside regulatory oversight, continuing to stock discontinued or non-recommended therapies.9 The public health implication is unequivocal: strengthening drug regulation and supply chain integrity is paramount. However, a singular focus on enforcement is insufficient without addressing the drivers of demand. For many Nigerians, especially in rural areas, Patent and Proprietary Medicine Vendors (PPMVs) are the first and most accessible point of care for fever and other common illnesses.18 Therefore, a strategic intervention must involve the formal integration and training of PPMVs rather than their mere sanctioning. Successful models demonstrate that training PPMVs on malaria case management, coupled with support to stock quality-assured ACTs, can transform these informal outlets into extensions of the formal health system, improving access to correct treatment while gradually displacing the market for obsolete drugs like CQ.19
The adherence rate of 70.5% to ACTs, while consistent with challenges across sub-Saharan Africa, is underpinned by modifiable determinants. The powerful association between treatment completion and obtaining medicines from formal sources underscores the vital role of professional diagnosis and guidance. This highlights a critical intervention point: improving diagnostic practices. Studies in Nigeria show that adherence to malaria treatment guidelines is significantly higher among public healthcare workers compared with those in the private sector, partly due to better availability and use of malaria rapid diagnostic tests (mRDTs) in public facilities.20 Scaling up access to and compulsory use of mRDTs in all treatment settings, including engaged PPMVs, is essential to curb presumptive treatment and ensure ACTs are used appropriately. Concurrently, the identification of cost as the predominant barrier demands innovative financial strategies. Lessons from other sectors suggest that blanket subsidies can be fiscally unsustainable. A more targeted approach, such as vouchers for vulnerable populations or integrating ACTs into community-based health insurance schemes, could protect households from catastrophic expenditure while encouraging care-seeking at formal or formalised outlets. Ultimately, instituting basic universal health coverage is imperative to address not only malaria but other major endemic diseases, removing financial barriers and ensuring equitable access to quality care.
Furthermore, the role of specific knowledge as a predictor of adherence reveals a crucial public information deficit. The low awareness of drug resistance (34.0%) and the importance of full treatment completion (25.0%) indicates that current health education is failing to convey core concepts for containment. This necessitates a strategic shift in behaviour change communication, developed in partnership with communities and delivered through trusted channels, including trained PPMVs.21 Messages must clearly articulate the link between individual adherence and the collective threat of drug resistance, fostering a sense of shared responsibility for preserving drug efficacy.
Importantly, the widespread use of CQ and incomplete ACT courses pose a tangible threat in the context of evolving parasite genetics. While no validated markers of artemisinin partial resistance were reported in recent Nigerian molecular surveillance, the persistent presence of CQ-resistant Pfcrt genotypes indicates ongoing selective pressure from continued CQ use.9 This highlights a non-negotiable pillar of any public health strategy: the establishment of a robust, nationally coordinated molecular surveillance system. Proactive genetic monitoring of parasite populations is essential to detect resistance markers early and guide timely policy adjustments, ensuring Nigeria does not remain uninformed in the face of this ever-present threat.
In conclusion, the challenges documented in Osun State are interconnected and demand a cohesive, multisectoral response. An effective strategy must simultaneously: (1) formally integrate and train PPMVs to improve frontline access to correct diagnosis and quality-assured ACTs; (2) scale up diagnostic testing and guideline adherence across all sectors; (3) develop targeted financial protections to reduce cost barriers; (4) launch nuanced communication campaigns on resistance and adherence and (5) invest in molecular surveillance for evidence-based policy. By synchronising these efforts, policymakers can transform the identified barriers into opportunities for strengthening the health system, safeguarding ACT efficacy and accelerating progress towards malaria control targets in Nigeria.
Limitations
The interpretation of these findings must consider several methodological constraints. The cross-sectional design precludes causal inference, meaning associations cannot be definitively labelled as causes. The study did not capture formal diagnostic confirmation status as a distinct variable, which limits our ability to distinguish between participants who received a formal diagnosis versus those who self-medicated. This represents an important area for future research. The over-representation of females in the sample is acknowledged; however, this likely reflects the demographic reality of the communities, as women are more frequently present at home during daytime survey hours, rather than a sampling flaw. The over-representation of urban residents and students, however, may affect generalisability to the broader adult population of Osun State, potentially leading to an overestimation of education levels and urban health-seeking norms. Furthermore, adherence was measured via self-report, which is susceptible to recall and social desirability bias, likely resulting in an overestimation of true completion rates. Finally, the study did not include molecular surveillance to correlate the observed behavioural practices with actual parasite resistance markers, which represents an important avenue for future integrated research.
Conclusions
This study elucidates the complex behavioural and systemic factors compromising antimalarial treatment adherence in south-western Nigeria. The enduring use of CQ, coupled with financial barriers and specific knowledge gaps, fosters an environment that threatens the long-term utility of first-line ACTs. The evidence underscores that improving adherence is not merely a matter of patient education but requires integrated, multisectoral strategies. These must encompass enforced regulation of drug markets, financial support to reduce cost barriers, reliable provision of quality-assured medicines through formal channels, addressing drug unavailability in rural areas, and targeted communication campaigns focused on resistance awareness. Concerted action on these fronts is urgently needed to optimise individual treatment outcomes, slow the selection of resistant parasites and protect the core chemotherapeutic tools for malaria control in Nigeria.
Supplementary material
Acknowledgements
The authors would like to express their profound appreciation to the Osun State Ministry of Health, community leaders, field assistants, and all study participants for their involvement and support.
Footnotes
Funding: The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Provenance and peer review: Not commissioned; externally peer reviewed.
Handling editor: Mark G Shrime
Patient consent for publication: Consent obtained directly from patient(s).
Ethics approval: This study involves human participants and was approved by Osun State Health Research Ethics Committee (OSHREC/PRS/569T/776). Participants gave informed consent to participate in the study before taking part.
Data availability free text: The anonymised datasets generated and analysed during this study are not publicly available due to confidentiality and ethical restrictions concerning participant data from a vulnerable population. However, the data are available from the corresponding author (SAO) on reasonable request, subject to approval from the Osun State Health Research Ethics Committee (OSHREC).
Collaborators: Not applicable.
Patient and public involvement: Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.
Data availability statement
Data are available on reasonable request.
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Data Availability Statement
Data are available on reasonable request.