Women who smoke during pregnancy increase the risk of both obesity and gestational diabetes mellitus in their daughters, according to a study.
While the relation of prenatal tobacco exposure to negative outcomes in childhood has been much studied, reports on possible adverse effects that persist until adulthood are more scarce and results have been inconsistent, according to background information in the study, which was published May 20 on the website of the journal Diabetologia.
In the study using data from the Swedish Medical Birth Register, researchers with Lund University in Sweden and the National Institute of Environmental Health Sciences, part of the National Institutes of Health in the United States, investigated the relationship between a womans smoking in pregnancy and her daughters subsequent chances of developing gestational diabetes and obesity.
Data were retrieved from the Medical Birth Register of Sweden for women who were born in 1982 (when smoking data were first registered) or later and who had given birth to at least one child; 80,189 pregnancies were included. The data on maternal smoking behavior in the register were categorized into three categories: non-smokers, moderate smokers (one to nine cigarettes a day) and heavy smokers (more than 9 cigarettes a day). Among the daughters studied, 7,300 subsequently became obese and 291 developed gestational diabetes when they were pregnant.
The risk of gestational diabetes was increased by 62% among women who were moderately exposed to smoking in the womb and 52% among those heavily exposed. The women moderately exposed were 36% more likely to be obese and those heavily exposed 58% more likely to be obese. The associations remained after adjustment for age, parity, body mass index, mode of delivery, gestational age and birth weight.
Possible mechanisms behind the associations, the authors suggested, could include alterations in the regulation of appetite and satiety, which has been found in animal studies. Other reported effects of prenatal nicotine exposure include a higher rate of death of the insulin-producing beta cells in the pancreas and increased adipocyte differentiation, which could be involved in the development of diabetes and obesity, respectively.
The authors added that recent data show epigenetic changes in the offspring of smoking mothers. They caution though, that unmeasured differences in diet or other factors between families with and without smokers could possibly account for the associations observed.
“In conclusion, these data show that women exposed to smoking during fetal life are at higher risk of developing gestational diabetes and obesity in adulthood,” the authors stated. “Although short-term detrimental effects of smoking on the individual and her offspring are well-known, such associations might extend into adulthood, making the incentive stronger for undertaking preventable measures, particularly as numbers in some countries point to an increase in daily smoking among young women.”
A PDF of the study — “Maternal smoking during pregnancy and daughters risk of gestational diabetes and obesity,” by Kristina Mattson et al — is available at www.diabetologia-journal.org.