The Risk of Gestational Diabetes Mellitus Following Bereavement: A Cohort Study from Denmark and Sweden

BackgroundWe investigated whether bereavement of a close family member - a source of severe psychological stress exposure - the year before pregnancy is associated with gestational diabetes mellitus (GDM). MethodsWe studied pregnant women with livebirths in Denmark during 1994-2008 and with births in Sweden during 1987-2006 (n=2569446). We obtained data on death of women's parents, siblings, and older children, and on demographic and health- and pregnancy-related factors through linkage between nationwide registers. ResultsIn multivariable models, death of a close relative the year before pregnancy was associated with a 14% increased odds of GDM [95% confidence intervals (CIs) 1.03, 1.26]. The odds ratios corresponding to the loss of a child, parent, and sibling were 1.51 (95% CI: 1.17, 1.95), 1.12 (95% CI: 1.00, 1.25), and 0.68 (95% CI: 0.40, 1.25), respectively. Deaths due to cardiovascular diseases or diabetes were more closely related to the risk of GDM than other types of deaths. We found no association between unnatural deaths and the risk of GDM. ConclusionsDeath of a close relative the year before pregnancy was associated with a modestly increased GDM risk. Our findings according to the relative's cause of death suggest that differences in screening for GDM among exposure groups and residual confounding by familial factors related to metabolic and cardiovascular diseases may have contributed to this association. If there is a causal stress effect on GDM in this predominantly Nordic population, it is most likely small.