Life course socioeconomic position is associated with inflammatory markers: the Framingham Offspring Study

Abstract

Associations between life course socioeconomic position (SEP) and novel biological risk markers for coronary heart disease such as inflammatory markers are not well understood. Most studies demonstrate inverse associations of life course SEP with C-reactive protein (CRP), interleukin-6 (IL-6) and fibrinogen, however little is known about associations between life course SEP and other inflammatory markers including intercellular adhesion molecule-1 (ICAM-1), tumor necrosis factor II (TNFR2), lipoprotein phospholipase A2 (Lp-PLA2) activity, monocyte chemoattractant protein-1 (MCP-1) or P-selectin. The objectives of this analysis were to determine whether three life course SEP frameworks ("accumulation of risk", "social mobility" and "sensitive periods") are associated with the aforementioned inflammatory markers. We examined 1413 Framingham Offspring Study participants (mean age 61.2+/-8.6 years, 54% women), using multivariable regression analyses. In age- and sex-adjusted regression analyses, cumulative SEP ("accumulation of risk" SEP framework), for low vs. high SEP, was inversely associated with CRP, IL-6, ICAM-1, TNFR2, Lp-PLA2 activity, MCP-1 and fibrinogen. We found that there were few consistent trends between social mobility trajectories and most inflammatory markers. Own educational attainment was inversely associated with 7 of 8 studied inflammatory markers, while father's education, father's occupation and own occupation were inversely associated with 4, 5 and 4 inflammatory markers, respectively, in age- and sex-adjusted analyses. The strengths of association between SEP and inflammatory markers were typically substantially accounted for by CHD risk markers (smoking, body mass index, systolic blood pressure, total:HDL cholesterol ratio, fasting glucose, medications, depressive symptomatology) suggesting these may be important mechanisms that explain associations between SEP and the studied inflammatory markers.

Figure 1

Conceptual frameworks for three different frameworks to conceptualize socioeconomic position (SEP) across the life course: (A) Accumulation of Risk, (B) Social Mobility, and (C) Sensitive Periods.