Combined impact of smoking, alcohol and social inequalities on premature mortality in urban India.

Associations with mortality of social inequalities, smoking and drinking differ widely between populations. Here we recruited 500,810 adults aged ≥35 years from Chennai city during 1998-2001 in South India and followed to 2020 for verbal-autopsy-assessed cause-specific mortality. Among those initially without chronic disease, multivariable-adjusted Cox regression (censored at age 70 years) related initial characteristics to mortality rates. Even among non-smoking non-drinkers, those with no schooling had almost three times the mortality rate ratio (RR) of those with >11 years education (men, RR of 2.76, 95% confidence interval (CI) 2.58-2.95; women, RR of 2.93, 95% CI 2.69-3.19), with substantial mortality excesses from each major disease category. These social inequalities were further exacerbated by much higher smoking and drinking prevalences among less educated men. Adjusted for education, male smoking (versus not, RR of 1.26, 95% CI 1.22-1.29) and drinking (versus not, RR of 1.52, 95% CI 1.48-1.56) were independently associated with risk and together almost doubled male mortality (both versus neither, RR of 1.89, 95% CI 1.84-1.94). Few women (<0.1%) smoked or drank.