Cortisol activity partially accounts for a relationship between community socioeconomic position and atherosclerosis.

ABSTRACT

Compared to others, individuals living in communities of socioeconomic disadvantage experience more atherosclerotic cardiovascular disease (CVD) and a greater extent of preclinical atherosclerosis. Although the mechanisms underlying these associations remain unclear, it is widely hypothesized that alterations in normative cortisol release from the Hypothalamic Pituitary Adrenal (HPA) axis may play a role in linking lower community socioeconomic position (C-SEP) to CVD risk. The current study examined this hypothesis in relation to a marker of preclinical atherosclerosis among 488 healthy midlife adults (30-54 years, Mean age= 43, 52% Female, 81% White). All participants were employed and without clinical CVD. C-SEP was estimated from census tract data, and atherosclerosis was measured as intima-medial thickness of the carotid arteries (cIMT) by duplex ultrasonography. Four indicators of HPA activity [cortisol at awakening and the cortisol awakening response (CAR), rate of diurnal decline in cortisol (diurnal slope), and total output expressed as area under the curve (AUC)] were derived from salivary cortisol measurements obtained from 5 samples on each of 3 working days. Path analyses were used to examine associations of C-SEP with cIMT and HPA activity and to test whether individual differences in HPA activity could account for any association of C-SEP with cIMT using bootstrapping (5000 iterations). All models were adjusted for age, sex, race, and composite measures of both individual-level socioeconomic position (income, education, occupation), and cardiometabolic risk (systolic and diastolic blood pressure, waist circumference, fasting lipids and glucose). Lower C-SEP was related to both greater cIMT (b = -0.004, p = .021) and a flatter diurnal slope of cortisol (b = -0.001, p = .039). An indirect effect showed attenuated diurnal slope to partially mediate the relationship between C-SEP and cIMT (95% CI = -0.0018 to -0.0001), and a residual direct effect of C-SEP on cIMT remained significant (95% CI = -0.0097 to -0.004). These results suggest that low C-SEP associations with preclinical atherosclerosis may be due in part to correlated variation in adrenocortical activity.