Dynamics of health behaviours and socioeconomic differences in mortality in the USA

To measure the explanatory role of behavioural factors to educational and income disparities in mortality among US adults (ages 25+).

Data were from four waves of the American Changing Lives Study (N=3617). There were 1832 deaths between 1986 and 2011. Smoking, physical activity, alcohol and body mass index were examined.

Those with 0-11 years of schooling had an 88% (95% CI 48% to 139%) increased risk of dying compared to those with 16+years of schooling. Behavioural factors explained 41% (95% CI 26% to 55%) and 50% (95% CI 30% to 70%) of this excess in models that treated behavioural factors as fixed (single point in time) and time varying (repeated), respectively. The lowest income group (bottom 20th centile) had a 209% (95% CI 172% to 256%) increased risk of dying relative to the highest income group (top 40th centile). Behavioural factors explained 24% (fixed, 95% CI 13% to 35%) and 39% (repeated, 95% CI 22% to 56%) of this difference. Analyses of deaths by causes indicated that behavioural factors were more consequential to disparities in cardiovascular mortality, explaining up to 83% of educational differences, compared to cancer and other death causes.

Behavioural factors are one of a number of factors which explain socioeconomic mortality disparities, but their estimated explanatory role depends on a number of parameters including the socioeconomic status measure examined, the cause of death and age. In this nationally representative sample, findings based on repeated measures did not warrant a re-evaluation of earlier estimates.