Consanguinity and Its Health Impacts on Human Populations: Insights from a Study of the Sivagangai Population in South India

Abstract

Inbreeding is a customary practice in South India, often involving consanguineous marriages that increase genetic homozygosity and the risk of recessive disorders. This population-based cross-sectional study assessed the prevalence, degrees, and genetic consequences of consanguinity among 6,518 families using stratified random sampling. The results showed a consanguinity rate significant over generations (P < 0.0001). While first-cousin and maternal-uncle marriages persist, their prevalence has increased over time. The study highlights the trend in consanguineous marriages across generations in the Sivagangai district, likely due to increased awareness of genetic risks and evolving societal norms. However, consanguinity remains prevalent, particularly among older generations, reflecting historical endogamous practices. The findings also reveal a higher prevalence of adult diseases, including diabetes (63.2%), heart disease (88.5%), and hearing deficits (88.2%), among individuals from consanguineous unions, reinforcing the genetic risks associated with close-kin marriages.