PLOS One · Nov 12, 2026

A prospective longitudinal population-based cohort study of non-communicable diseases (NCDs) in Ghana, India, and Nepal (The GIN NCDs Study): A study protocol

By Simkhada P, Simkhada B, Sah RK et al.

BACKGROUND: Non-communicable diseases (NCDs) are the leading cause of death globally, disproportionately affecting low-and-middle-income countries (LMICs). In Ghana, India, and Nepal, the NCD burden is rising due to urbanisation, demographic shifts, and lifestyle changes. Existing national datasets are largely cross-sectional, limiting insights into disease progression and intergenerational health patterns. Longitudinal evidence is urgently needed to inform prevention and care strategies. METHODS: All residents aged ≥18 years residing in the study areas will be invited to enrol at baseline, with plans to include younger age groups in future waves. Data will be collected at baseline, Year 2, and Year 4 using harmonised tools adapted from the World Health Organization's STEPwise approach to Surveillance (WHO STEPS) instruments. Domains include socio-demographics, climate related exposures and impacts, lifestyle factors, health-seeking behaviours, mental and physical health, and physical and anthropometric measurements. Primary outcomes include hypertension, diabetes, chronic respiratory diseases, mental health disorders, dementia, and multimorbidity. The cohort is powered to estimate the prevalence of raised blood pressure with ±3% precision, assuming a design effect of 1.5, 10-15% non-response, and 10% annual attrition. Required baseline sample sizes are calculated as: 2,211 (India), 2,126 (Nepal), and 2,262 (Ghana). To achieve precision within rural, peri-urban, and urban strata, these totals will triple to 6,628 (India), 6,378 (Nepal), and 6,786 (Ghana). Sampling will follow a two-stage cluster design with household-level enrolment. Analyses will use multivariable mixed-effects models guided by a directed acyclic graph (DAG) framework. DISCUSSION: This study will generate longitudinal evidence on NCD risk factors, multimorbidity, and mental health in LMICs, addressing critical data gaps. Its household-based design enables exploration of shared exposures and intergenerational influences, supporting life-course analyses. Findings will inform targeted interventions, health system planning, and policy frameworks aligned with the WHO Global Monitoring Framework and Sustainable Development Goal (SDG) Target 3.4.

doi.org/10.1371/journal.pone.0362114PubMed 43019331Populations