Differences in morbidity and mortality between socioeconomic groups constitute one of the most consistentfindings of epidemiologic research. However, research on social inequalities in health has yet to provide acomprehensive understanding of the mechanisms underlying this association. Data from two large Europeancohorts were used to examine socioeconomic differences in all-cause and cause-specific mortality in twopopulations in early old age, as well as the role played by health behaviours and social support in shapingthose inequalities. Indicators of socioeconomic circumstances in early life were found to be related tomortality in adulthood, even though the association of the three measures examined, father’s occupationalposition, education and height, with mortality did not have the same shape and depended on the cause ofmortality being examined. Indicators of socioeconomic position in adulthood, occupational position andincome, were strongly associated with all-cause and cardiovascular mortality in both cohorts. In theWhitehall II study, health behaviours - smoking, alcohol consumption, diet and physical activity - werestrongly socially patterned, and were found to contribute to a large part of social inequalities in mortality,particularly when changes in these behaviours over time were taken into account. The same behaviourscontributed little to explaining social inequalities in mortality in the GAZEL cohort, as their socialpatterning was weak in this cohort. Of the measures of social support examined, marital status alsoaccounted for part of the socioeconomic gradient in mortality in the Whitehall II cohort but not in GAZEL,while the role of social participation and network size was negligible in both cohorts. Different mechanismsmay be driving social inequalities in health in two neighbouring European countries. This finding calls forfurther comparative research to understand the common and unique determinants of social differences inhealth within and between countries, and for additional research addressing the fundamental causes of socialinequalities in health.
