Burden of Cardiovascular Disease Risk Factors Over 13.5 Years in a Rural and Urban South Indian Cohort in Comparison with Global Data

Background: India has high mortality rates from cardiovascular disease (CVD). Understanding the trends and identifying modifiable determinants of CVD risk factors will guide preventive strategies and support policy making. Methods: We estimated the prevalence and incidence of CVD risk factors (overweight, obesity, central obesity, type 2 diabetes (T2D), hypertension, hypercholesterolemia and hypertriglyceridemia) in 962 (male 519) non-migrant adults from Vellore, South India, studied in i) 1998-2002 (baseline, mean age 28.2 years) and ii) 2013-2014 (follow-up, mean age 41.7 years). Prevalence was compared with the Non-Communicable Disease Risk Collaboration (global) data. Incidence was compared with another Indian cohort from New Delhi (NDBC). Regression analysis was used to test baseline predictors of incident CVD risk factors. Findings: The prevalence of CVD risk factors at 28 and 42 years was 17% and 51% for overweight/obesity, 19% and 59% for central obesity, 3% and 16% for type 2 diabetes, 2% and 19% for hypertension and 15% and 30% for hypertriglyceridemia. The prevalence of type 2 diabetes at baseline and follow-up and hypertension at follow-up was comparable with or exceeded that in high income countries despite lower obesity rates. The incidence of most risk factors was lower in Vellore than in the NDBC. Weight gain from 15 to 28 years, and 28-year waist circumference, strongly predicted incident type 2 diabetes, hypertension and hypertriglyceridemia. After adjusting for these, rural residents had a higher incidence of type 2 diabetes and hypertension. Interpretation: A high prevalence of CVD risk factors is evident at a young age among Indians compared with high and upper-middle income countries. The rural prevalence is catching up with urban rates. Adiposity predicted higher risk factors, but the prevalence of hypertension and T2D is higher than expected given a relatively low obesity prevalence in global terms. This suggests greater sensitivity to adiposity and/or other unmeasured causal factors, among Indians. The increasing burden of CVD risk factors in India reinforces the need for strengthening CVD risk-prevention strategies, particularly in rural India and starting from a young age. Funding Statement: British Heart Foundation, UK and Christian Medical College, Vellore, India Declaration of Interests: None. Ethics Approval Statement: The study was approved by the institutional ethics committee of the Christian Medical College, Vellore and all participants provided informed consent.