Genetic epidemiology of blood pressure in two Indian populations: some lessons

A genetic epidemiological study of blood pressure was conducted in two contrasting populations: the Marwaris of Calcutta and the Hindu middle-caste agriculturists of Digha. The Marwaris are heavier and significantly more obese than the agriculturists. The prevalence of hypertension among the Marwaris (17%) is more than tenfold higher than that among the agriculturists (1.4%). Genetic analysis of blood pressure data using a path model indicates that blood pressure levels (adjusted and standardized for age, gender, education level, and disease status) are primarily determined by environmental factors, as measured by their effects on anthropometric characters. The observed familial resemblance of blood pressure levels in the two populations is primarily due to cultural rather than genetic inheritance. Genetic and familial effects on covariation between anthropometric measures of obesity and blood pressure levels are perhaps so strong that there is no residual genetic heritability of adjusted blood pressure levels.