A major long-term study of half a million adults in Chennai, India, has found that social inequality remains a powerful predictor of premature death, even among people who neither smoke nor drink alcohol. The study, conducted by researchers at the Epidemiological Research Centre in Chennai in collaboration with the Nuffield Department of Population Health, also shows that tobacco and alcohol use substantially worsen these inequalities among men. The study is published in Nature Health.
The study followed 458,609 men and women aged 35 and over, recruited between 1998 and 2001 and tracked until 2020. Researchers examined how education level (a key marker of social inequality) alongside smoking and alcohol use, influenced the likelihood of dying prematurely (before age 70).
Over the study period, more than 52,000 participants died prematurely. Among people who neither smoked nor drank alcohol, there were strong social inequalities in mortality. People with no formal education had nearly three times the risk of dying in middle age compared with those who had more than 11 years of schooling. This pattern was consistent in both men and women.