Fetal and life course origins of serum lipids in mid-adulthood : results from a prospective cohort study

Background: During the past two decades, the hypothesis of fetal origins of adult disease has received considerable attention. However, critique has also been raised regarding the failure to take the explanatory role of accumulation of other exposures into consideration, despite the wealth of evidence that social circumstances during the life course impact on health in adulthood. The aim of the present prospective cohort study was to examine the contributions of birth weight and life course exposures (cumulative socioeconomic disadvantage and adversity) to dyslipidemia and serum lipids in mid-adulthood. Methods: A cohort (effective n = 824, 77%) was prospectively examined with respect to self-reported socioeconomic status as well as stressors (e.g., financial strain, low decision latitude, separation, death or illness of a close one, unemployment) at the ages of 16, 21, 30 and 43 years; summarized in cumulative socioeconomic disadvantage and cumulative adversity. Information on birth weight was collected from birth records. Participants were assessed for serum lipids (total cholesterol, low- and high-density lipoprotein cholesterol and triglycerides), apolipoproteins (A1 and B) and height and weight (for the calculation of body mass index, BMI) at age 43. Current health behavior (alcohol consumption, smoking and snuff use) was reported at age 43. Results: Cumulative life course exposures were related to several outcomes; mainly explained by cumulative socioeconomic disadvantage in the total sample (independently of current health behaviors but attenuated by current BMI) and also by cumulative adversity in women (partly explained by current health behavior but not by BMI). Birth weight was related only to triglycerides in women, independently of life course exposures, health behaviors and BMI. No significant association of either exposure was observed in men. Conclusions: Social circumstances during the life course seem to be of greater importance than birth weight for dyslipidemia and serum lipid levels in adulthood. Background Since the early 1990 s, the research field of life course epidemiology has studied the health effects of biological and social exposures during different periods of life and the corresponding long-term processes spanning over the life course [1]. One line of research focuses on fetal origins of disease, with one hypothesis stating that suboptimal metabolic conditions during fetal life, e.g. indicated by lower birth weight, increase the risk for cardiovascular disease in adulthood [2]. Low birth weight has been shown to be associated with cardiovascular mortality [3,4] and to predict a number of related disorders, such as hypertension, obesity and insulin resistance [5-7]. The fetal origins hypothesis has, however, been criticized for overestimation of effects [8] and failure to consider the wealth of other exposures between birth and adulthood. One of the challenges of studying the fetal origins hypothesis is how to incorporate confounding and explanatory effects of accumulated stress over the life span into the analyses [9], which is a manifest limitation of past and present research on the field. The present study will address this issue by examining the importance of birth weight as well as social