Maternal smoking during pregnancy - Long-term health effects in the offspring

Abstract: Globally, around 10 % of women smoke during pregnancy today. It is known that pregnancy smoking increases the risk of adverse short-term health effects in the offspring, such as preterm birth, low birthweight and spontaneous abortion. Less is known about whether any adverse health effects persist until adulthood. In Sweden, there are nationwide population-based health registers that are becoming intergenerational, which lend themselves well for the study of such associations. This thesis is primarily based on the Swedish Medical Birth Register, which covers almost all births in Sweden since 1973. Additional data sources include a perinatal quality register (Perinatal Revision South Register), a regional biobank (Malmö Maternity Unit Serum Biobank), and prospective clinical study cohorts including all children who developed type 1 diabetes in Skåne between 1999 and 2005 (The Diabetes Prediction in Skåne Cohort, The Skåne Study and Better Diabetes Diagnosis Study). The aim of this thesis was to investigate if maternal smoking during pregnancy was associated with long-term health effects in her offspring, by specifically looking at the risk of childhood type 1 diabetes, as well as the risk of obesity, gestational diabetes and preeclampsia in adult women. We also investigated the validity of the self-reported smoking data in the Medical Birth Register, by the use of biomarker measurements. We found a higher risk of both type 1 diabetes, obesity and gestational diabetes in those exposed to tobacco smoking prenatally, but less consistent associations with preeclampsia. The validity of the self-reported smoking data in the Medical Birth Register was found to be high. In conclusion, our studies suggest that maternal pregnancy smoking could have long-term health effects for her children, so there is reason to continue to make efforts to help women quit smoking when they are pregnant. When performing research on pregnancy smoking, Swedish register-data are of good quality and can be used.