Endgame of the smoking epidemic in high-income countries reflected in life expectancy sex differences: a populations-based study

Abstract

Background Of all lifestyle behaviours, smoking caused the most deaths in the last century. Because of the time lapse between the uptake of smoking and the mortality from smoking, male and female smoking epidemiology often follows a typical double wave pattern dubbed the ‘smoking epidemic’. How is this epidemic progressing, how does it affect male-female survival differences, and how does it act on a cohort-by-age basis?Methods We examine changes in smoking-attributable mortality fractions as estimated by the Preston-Glei-Wilmoth method by age group (ages 50-85) across birth cohorts 1870-1965, utilizing data from the WHO mortality database and the human mortality database. We compare these to changes in the sex differences in life expectancy at age 50 in three geographic regions that have progressed farthest into the smoking epidemic: high-income North America, Europe and Oceania.Results We find that for older cohorts (~1910-1930) for most ages, smoking-attributable mortality has broadly been stable or declining for males while growing for females, contributing to a decline in the advantage of women in terms of life expectancy from around 4.5 years towards 2 years. Yet more recent cohorts (~1955-1965) show a precipitous decline in smoking mortality for all age groups available.Conclusions In line with previous findings, the smoking epidemic contributed materially to the male-female survival gap and to the recent narrowing of that gap. In addition, the precipitous decline in smoking mortality in recent cohorts that we find suggests that the smoking epidemic in the three selected regions is ending or at least subsiding. Our results also give a glimpse of what low- and middle-income countries may expect in term of sex differences in smoking-attributable mortality and life expectancy. Our approach shows that a cohort-by-age analysis is helpful in tracking the smoking epidemic.