In modern welfare states, socio-economic inequalities in mortality are large and persistent, with people with low socio-economic position (SEP) living, on average, 3-10 years less than people with high SEP. Smoking, alcohol misuse and obesity are key lifestyle factors known to contribute importantly to socioeconomic mortality inequalities as well to general mortality trends. The extent to which these lifestyle factors contribute differentially to trends over time in mortality inequalities by socio-economic groups has, however, barely been researched.
In their study, Fanny Janssen (Netherlands Interdisciplinary Demographic Institute (NIDI) and University of Groningen), and her (inter)national collaborators estimated – for the first time - the combined impact of smoking, alcohol, and obesity on levels of and trends in educational inequalities in remaining life expectancy at age 30 (e30) in England & Wales, Finland, and Italy (Turin). For this, they used annual individually-linked (cause-specific) mortality data by educational level (low, middle, high) and carefully selected techniques to estimate smoking-, alcohol-, and obesity-attributable mortality, both separately and combined.
Their comparative population-level study found that smoking, alcohol misuse and obesity individually contributed 23%, 14%, and 10%, respectively, to the average educational inequality in e30 of 4.4 years in 1992-2017; and 44% combined. The combined contribution was higher among males (2.7 out of 5.2 years; 51%) compared to females (1.2 out of 3.5 years; 34%), largely driven by sex differences in smoking and alcohol misuse. The highest contribution for Italy among males (60%) and for England & Wales among females (43%) resulted from, respectively, the relative late timing of the smoking epidemic among Italian males, and the forerunner position in the smoking epidemic of E&W females, representing both substantially higher smoking-attributable mortality among the low-educated compared to the high educated.
The combined impact of smoking, alcohol and obesity on educational inequalities in e30 increased among Finnish males up to 2008, Italian males, and British and Finnish females. Without smoking-, alcohol-, and obesity-attributable mortality, the observed increases in educational inequalities in e30 among Finnish males (1987-2008), Finnish females (1987-2017), and Italian males (1990-2018) were approximately halved. Smoking-, alcohol-, and obesity-attributable mortality combined tempered the decline in educational inequalities in e30 among British females (1992-2017), and was responsible for the reversal in 2008 from increasing to declining educational inequalities in e30 among Finnish males.
Together, these findings suggest that targeting socio-economic inequalities in health behaviours – and in particular smoking and alcohol misuse – cannot only substantially reduce socio-economic inequalities in e30, but also diminish the increasing trends in these inequalities over time. The observed sex and country differences in the individual lifestyle factors that contributed the most to the observed educational inequalities in e30 demonstrate the need for context-specific strategies.
Funding
This work is financed by the Netherlands Organisation for Scientific Research (NWO) as part of the research programme “Forecasting future socio-economic inequalities in longevity: the impact of lifestyle ‘epidemics’”, under grant no. VI.C.191.019. See: www.futurelongevitybyeducation.com.