Challenges in setting up a large population-based prospective cohort study in India - learnings from the LoCARPoN cohort.

Population-based prospective cohort studies can yield vital new evidence. However, they are difficult to setup especially in non-western contexts such as India. We describe our experience in establishing the Longitudinal Cognition and Aging Research on Population of the National Capital Region (LoCARPoN) cohort, which was the first-of-its-kind public-funded study with target sample size of 15,000, 3 sites, and funds of approx. US$ five million for eight years (2014-2022). LoCARPoN aimed to study incident stroke and dementia in adults aged ≥50 years in urban and rural populations of north India. Among the numerous challenges encountered, important were inadequate funding, lack of adequate space for medical and field sites, difficulty in hiring manpower, lack of IT infrastructure, non-availability of storage facility for biological samples, and absence of dedicated MRI machines. Meticulous planning, adequate funding, trained personnel, institutional and community support are critical for establishing such cohorts in the non-western contexts. Funding: The LoCARPoN cohort study was funded by the Department of Biotechnology (Grant No. BT/IN/Netherlands/03/KP/2012 dated 14/02/2014); and Department of Health Research (Grant No. R.11012/15/2018-HR, dated 09/08/2018), Government of India. The Erasmus component was funded through the Erasmus Medical Centre, Rotterdam, The Netherlands, and the Erasmus University, Rotterdam (Alzheimer NederlandWE.15-2014-09).