Effects of Pre- and Postnatal Early-Life Stress on Internalizing, Adiposity and Their Comorbidity.
OBJECTIVE Depression and obesity are two highly prevalent and often comorbid conditions. Exposure to early-life stress (ELS) has been associated with both depression and obesity in adulthood, as well as their preclinical manifestations during development. However, it remains unclear whether: (i) associations differ depending on the timing of stress exposure (prenatal vs postnatal) and (ii) ELS is a shared risk factor underlying the comorbidity between the two conditions. METHOD Leveraging data from two large population-based birth cohorts (ALSPAC: n=8428 (52% male participants); Generation R: n=4268 (48% male participants)), we constructed comprehensive cumulative measures of prenatal (in utero) and postnatal (from birth to 10 years) ELS. At age 13.5 years we assessed: a) internalizing symptoms (using maternal reports); b) fat mass percentage (using dual-energy X-ray absorptiometry); c) their comorbidity, defined as the co-occurrence of high internalizing and high adiposity. RESULTS Both prenatal (total effect [95%CI] = 0.20 [0.16;0.22]) and postnatal stress (β [95%CI] = 0.22 [0.17;0.25]) were associated with higher internalizing symptoms, with evidence of a more prominent role of postnatal stress. A weaker association (primarily driven by prenatal stress) was observed between stress and adiposity (prenatal: 0.07 [0.05;0.09]; postnatal: 0.04 [0.01;0.07]). Both pre- (OR [95%CI] = 1.70 [1.47;1.97]) and postnatal stress (1.87 [1.61;2.17]) were associated with an increased risk of developing comorbidity. CONCLUSION We found evidence of (i) timing and (ii) shared causal effects of ELS on psycho-cardiometabolic health in adolescence, but future research is warranted to clarify how these associations may unfold over time.