Childhood adversity and gestational diabetes: examining the mediating effect of BMI and depression through interventional mediation analysis.

backgroundChildhood adversity has been shown to increase the risk of gestational diabetes mellitus (GDM), though the mechanisms through which the risk is increased have yet to be examined.

methodsWe used register data on all women born in Denmark and giving birth for the first time between 2004 and 2018, totalling 207,659 women. Interventional mediation analysis was used to estimate how two mechanistic pathways, depression and pre-pregnancy BMI, mediate the relationship between childhood adversity and GDM across five previously identified adversity trajectory groups.

results4779 women were diagnosed with GDM between 2004 and 2018, corresponding to a 2.3% absolute risk of GDM. Compared to those who experienced low adversity in childhood, we estimated that those who experienced early material deprivation could have a 0.12% [95% CI 0.10, 0.14] reduction in absolute GDM risk by intervening on BMI and equalising its distribution to that of mothers in the low adversity group. We found no evidence of a reduction in risk if depression were similarly intervened on. For those in the high levels of adversity group no evidence of mediation was found.

conclusionsIntervening on pre-pregnancy BMI might potentially reduce the risk of GDM for mothers in some of the adversity groups, whereas intervening on depression seems to have little impact. The findings suggest that high adversity likely increases the risk of GDM through alternative mechanisms than BMI or depression.