Multi-cohort study identifies social determinants of systemic inflammation over the life course

Abstract

Chronic inflammation has been proposed as having a prominent role in the construction of social inequalities in health. Disentangling the effects of early life and adulthood social disadvantage on inflammation is key in elucidating biological mechanisms underlying socioeconomic disparities. Here we explore the relationship between socioeconomic position (SEP) across the life course and inflammation (as measured by CRP levels) in up to 23,008 participants from six European cohort studies from three countries conducted between 1958 and 2013. We find a consistent inverse association between SEP and CRP across cohorts, where participants with a less advantaged SEP have higher levels of inflammation. Educational attainment is most strongly related to inflammation, after adjusting for health behaviours, body mass index and later-in-life SEP. These findings suggest socioeconomic disadvantage in young adulthood is independently associated with later life inflammation calling for further studies of the pathways operating through educational processes.

Fig. 1

Overview of the study workflow. ^*NCDS is the only birth cohort, therefore father’s occupation was collected prospectively and mean age corresponds to the age of participants at the time of the biomedical survey

Fig. 2

Forest plot of regression coefficients [95% confidence interval] for the association between a father’s occupational position, b participant’s educational attainment, c participant’s last occupation and CRP concentration at baseline in random effect meta-analysis framework for the total population and by gender for Model 1 (Mod-1), after adjustment for each intermediate factor (+Alcohol, +Smoking, +BMI, +Sedentary) and further adjusted for all intermediate factors together (Mod-2). The high SEP group was used as reference, solid lines represent the medium SEP group and dotted lines the low SEP group. Meta-analyses results for the total population (in orange) includes N = 13,078 for early life SEP and N = 23,008 for later in life SEP, respectively, N = 7798 and N = 12,809 for men (in blue) and N = 5280 and N = 10,199 for women (in green)