Abstract P007: Maternal Heavy Smoking during Pregnancy in Association with Higher Risk of Gestational Diabetes in the Offspring

Introduction: Maternal smoking during pregnancy is an established risk factor for adverse perinatal outcomes. However, data on the intergenerational impact of maternal smoking during pregnancy on offspring’s long-term risk of adulthood disease are limited. Hypothesis: We assessed the hypothesis that maternal smoking during pregnancy may be associated with risk of gestational diabetes mellitus (GDM) in the offspring. Methods: The analytical population was composed of 10138 parous women in the Nurses' Health Study II cohort whose mothers participated in the Nurses’ Mothers’ Cohort Study; 819 of the nurses developed GDM. Data on maternal and paternal smoking during pregnancy and associated covariates were recalled by the nurses’ mothers. GDM diagnosis was self-reported by nurse participants and was validated by medical record review in a previous study. We used logistic regression models to estimate the odds ratios (ORs) and 95% confidence intervals (CIs). Results: We observed a significant association between maternal heavy smoking during pregnancy and risk of GDM in the offspring. The multivariable-adjusted ORs (95% CIs) of GDM among women whose mothers did not smoke during pregnancy, continued smoking 1-14, 15-24, and ≥ 25 cigarettes/day were 1.00 (reference), 1.13 (0.91-1.42), 1.17 (0.88-1.55), and 1.74 (1.03-2.95) (P for trend = 0.04), respectively. Further adjustment for the nurses’ birth weight, adult life variables and body mass index during various periods of life only slightly changed the association. No significant association was observed between paternal smoking during the pregnancy period and the risk of GDM. We further examined the joint effect of both maternal and paternal smoking during pregnancy on the risk of GDM. The nurses whose parents both smoked during pregnancy ≥ 15 cigarettes/day had an OR (95% CI) of 1.25 (0.94-1.66), compared with those whose parents did not smoke during pregnancy or smoked < 15 cigarettes/day. In an analysis on the joint effect of maternal smoking during pregnancy and the nurse’s smoking during adulthood, we found that the nurses who ever smoked during adulthood and their mothers ever smoked during the pregnancy with them had a significantly higher risk of GDM (OR 1.40, 95% CI 1.08-1.81), compared to the nurses neither themselves nor the mothers smoked. Conclusions: In conclusion, maternal heavy smoking (≥ 25 cigarettes/day) during pregnancy is significantly associated with higher risk of gestational diabetes in the offspring. Further studies are warranted to confirm our findings and to elucidate the underlying mechanisms.