Diurnal cortisol variation during pregnancy in Turkish origin and non-migrant women in a German birth cohort study.

BACKGROUND: Immigrants from Turkey experience health disadvantages relative to non-immigrant populations in Germany that are manifest from the earliest stages of the lifespan onwards and are perpetuated across generations. Chronic stress and perturbations of stress-responsive physiological systems, including the hypothalamus-pituitary-adrenal (HPA)-axis, are believed to in part mediate this relationship. Cortisol plays an important role in the association between maternal stress during pregnancy and many pregnancy-, birth- and offspring-related outcomes. We therefore examined whether maternal migrant background is associated with diurnal cortisol variation during pregnancy. METHODS: 109 pregnant women (incl. n = 32 Turkish origin women) that participated in a multi-site prospective cohort study in Germany collected saliva samples across the day on two consecutive days around 24 and 32 weeks gestation. Hierarchical linear models were applied to quantify associations between migrant background and diurnal cortisol variation across pregnancy. RESULTS: Women of Turkish origin exhibited a significantly lower cortisol awakening response (CAR) and a flatter diurnal cortisol slope (DCS) compared to non-migrant women after adjusting for household income. These relationships between migrant status and diurnal cortisol variation were mainly driven by 2nd generation migrants. DISCUSSION: A potential HPA axis dysregulation of Turkish-origin pregnant women may contribute to the intergenerational transmission of health disadvantages in this group.

Intergenerational transmission of health disparities among Turkish-origin immigrants in Germany: study protocol of a multi-centric cohort study (BaBi-stress and BaBeK study).

BACKGROUND: Immigrants in Germany exhibit higher levels of social disadvantage when compared to the non-immigrated population. Turkish-origin immigrants constitute an important immigrant group in Germany and show disparities in some health domains that are evident from birth onwards. Several studies have shown the mechanisms by which social disadvantage is biologically embedded to affect health over the lifespan. Relatively little, however, is still known about if and how the maternal social situation is transmitted to the next generation. This study therefore aims to analyse the effects of maternal socioeconomic status and migration status on stress-related maternal-placental-fetal (MPF) biological processes during pregnancy on infant birth and health outcomes. METHODS: This longitudinal cohort study of N = 144 child-mother dyads is located at two study sites in Germany and includes pregnant women of Turkish origin living in Germany as well as pregnant German women. During pregnancy, MPF stress biology markers from maternal blood and saliva samples, maternal socio-economic and migration-related information, medical risk variables and psychological well-being are assessed. After birth, infant anthropometric measures and developmental outcomes are assessed. The same measures will be assessed in and compared to Turkish pregnant women based on a collaboration with BABIP study in Istanbul. DISCUSSION: This is the first study on intergenerational transmission of health disparities in Germany with a focus on women of Turkish-origin. The study faces similar risks of bias as other birth cohorts do. The study has implemented various measures, e.g. culturally sensitive recruitment strategies, attempt to recruit and follow-up as many pregnant women as possible independent of their social or cultural background. Nevertheless, the response rate among lower-educated families is lower. The possibility to compare results with a cohort from Turkey is a strength of this study. However, starting at different times and with slightly different recruitment strategies and designs may result in cohort effects and may affect comparability of the sub-cohorts. TRIAL REGISTRATION: N.A. (Observational study, no clinical trial, no interventions on human participants).