In utero Exposure to Maternal Tobacco Smoke and Subsequent Obesity, Hypertension, and Gestational Diabetes Among Women in The MoBa Cohort

Background. Environmental factors influencing the developmental origins of health and disease need to be identified and investigated. In utero exposure to tobacco smoke has been associated with obesity and a small increase in blood pressure in children; however, whether there is a corresponding increased risk of conditions such as diabetes and hypertension during adulthood remains unclear.

Objectives. To assess the association of self-reported in utero exposure to tobacco smoke with the prevalence of obesity, hypertension, type-2 diabetes mellitus (T2DM), and gestational diabetes mellitus (GDM) in women aged 14-47 years.

Methods. We conducted a cross-sectional analysis of the Norwegian Mother and Child Cohort Study, which enrolled pregnant women in Norway from 1999-2008. Exposure to tobacco smoke in utero (yes vs. no) was ascertained on the baseline questionnaire (~17 weeks’ gestation); the outcomes were ascertained from the Medical Birth Registry of Norway and the questionnaire. Our analysis included 74,023 women.

Results. Women exposed to tobacco smoke in utero had 1.53 times the odds (OR) of obesity (95% confidence interval [CI], 1.45-1.61) relative to unexposed, after adjusting for age, education, and personal smoking. After further adjustment for body mass index, the OR for hypertension was 1.68 (CI, 1.19-2.39), for T2DM was 1.14 (CI, 0.79-1.65), and for GDM was 1.32 (CI, 1.10-1.58) among exposed compared with unexposed.

Conclusions. Exposure to tobacco smoke in utero was associated with obesity, hypertension, and GDM in adult women. The possibility that the associations were due to unmeasured confounding cannot be excluded.