SES inequalities in cause-specific adult mortality: a study of the long-term trends using longitudinal individual data for Sweden (1813-2014)

Higher socioeconomic status (SES) is associated with lower mortality, and this correlation has been confirmed using different indicators across several geographical settings. Nevertheless, the timing of the emergence of the SES gradient remains unclear. We used individual-level longitudinal data for a regional population in southern Sweden covering the period between 1813 and 2014, and we applied a cause-specific proportional hazard model. We estimated SES differences in all-cause, nonpreventable, preventable, and cause-specific adult mortality in four subperiods (1813-1921, 1922-1967, 1968-1989, 1990-2014) by gender adjusting for birth year, place of residence, marital status, and migration status. The SES gradient in mortality present today for both genders emerged only around 1970, and with few exceptions, it emerged at approximately the same time for all causes of death. It emerged earlier for women than for men, particularly in infectious diseases. In the nineteenth and early twentieth centuries, we found a positive association between SES and mortality from circulatory diseases for men. SES has not always been a fundamental cause of mortality; it only emerged as such in the second half of the twentieth century. We argue that habits and behaviors embedded in the different social strata played a major role in the emergence of the SES gradient.