OBJECTIVE: Prenatal smoking exposure is associated with obesity and other cardio-metabolic risk factors in children, but no previous meta-analysis has been conducted in adults.
METHODS: We investigated the association of prenatal smoking exposure in the Danish General Suburban Population Study (GESUS) with BMI, waist circumference, total cholesterol, type 2 diabetes, gestational type 2 diabetes, and hypertension in adulthood. We subsequently performed a meta-analysis, adding published studies investigating the association between prenatal smoking and the risk of cardio-metabolic outcomes among individuals at least 18 years of age.
RESULTS: We included 19 eligible observational studies with various cardio-metabolic outcomes (N = 24,201-308,981 adults). In individuals exposed to prenatal smoking, the pooled random effects adjusted odds ratio were 1.35 (95% CI: 1.16-1.56) for being overweight, 1.46 (1.39-1.54) for being obese, 1.07 (0.89-1.29) for type 2 diabetes, 1.17 (0.92-1.48) for hypertension, and 1.38 (1.19-1.61) for gestational diabetes mellitus (GDM), compared with no exposure. The standardized means in waist circumference, total cholesterol, diastolic, and systolic blood pressure were not different in individuals exposed vs. not exposed to prenatal smoking. Heterogeneity was moderate to high (51% < I 2 < 99%). However, removal of the high heterogeneity removed the associated uncertainty in the point estimate and revealed that prenatal smoking is associated with increased BMI in adulthood. There was also no evidence of publication bias in the meta-analyses.
CONCLUSIONS: The findings from the meta-analyses suggested that prenatal smoking exposure is associated with an increased odds ratio of overweight, obesity, and GDM in adulthood, but not with type 2 diabetes, hypertension, waist circumference, or total cholesterol. These findings highlight the importance of abstaining from smoking by pregnant women.