Life-course socioeconomic trajectories and diurnal cortisol regulation in adulthood

Although the health risk of socioeconomic disadvantage over the life-course is fairly established, the mechanisms are less studied. One candidate pathway is long-term dysregulation of cortisol. This study assesses whether socioeconomic trajectories from adolescence to adulthood influences the regulation of cortisol in mid-adulthood, and further investigates the importance of adolescence as a critical period and of accumulation of socioeconomic disadvantage. Participants were drawn from a 27-year prospective cohort study (n = 732, 68% of the original cohort). Information on socioeconomic status (SES) was collected at the ages of 16 (based on parental occupation), 21, 30 and 43 (based on own occupation) years, and at 43 years participants collected one-day salivary cortisol samples at awakening, after 15 min, before lunch and at bedtime. We found that the cortisol awakening response (CAR) differed with respect to SES trajectory; those with stable low or early low/upwardly mobile SES tended to display higher CAR than those with early high/downwardly mobile, highly mobile or stable high trajectories. Further analyses revealed that early low SES was related to higher CAR, and in women low SES was related to lower bedtime cortisol, independently of later SES and potential confounders. We found no support for a linear effect of accumulation of socioeconomic disadvantage. In conclusion, our study gives support for an independent effect of low socioeconomic status early in life, on the regulation of cortisol in adulthood. (C) 2009 Elsevier Ltd. All rights reserved.