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Prenatal snus use may harm BP, heart rate in preschool-age children
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Prenatal use of snus, a moistened smokeless tobacco product, may lead to higher systolic BP and altered heart rate variability in offspring by age 6 years, according to findings published in the Journal of the American Heart Association.
After adjusting for the age and height, researchers observed that children who were exposed to snus, and therefore nicotine, in fetal life had a 4.2 mm Hg higher systolic BP than those who were not exposed to tobacco (95% CI, 0.2-8.1).
Moreover, in an analysis of a subgroup of snus-exposed children, researchers found that the spectral heart rate variability ratio was greater in snus-exposed children (median, 0.69; interquartile range, 0.45-1.21) than the control group (median, 0.21; interquartile range, 0.32-0.57; P = .034).
Nicotine exposure
“By studying exposure to snus during pregnancy and breastfeeding, we were able to exclude both the influence of combustion toxins from cigarette smoke and that of secondhand smoke exposure during childhood,” the researchers wrote. “The difference of 4.2 mm Hg in systolic BP between snus-exposed children and controls is larger than the difference reported in studies of maternal smoking, commonly amounting to 1 to 3 mm Hg. If this reflects a dose-response relationship, [it] needs further exploration; in our study, only high-dose nicotine exposure was studied.”
In other findings, after standardization for age, sex and height, children with fetal snus exposure were found to be the 61st percentile for systolic BP while the control group was in the 46th percentile (difference, 15; 95% CI, 2-28), according to the study.
Researchers reported that although three children had supraventricular extrasystoles, and one child had a type II atrioventricular block during nighttime sleep, they all were in the control group, and there were no other arrhythmias or abnormalities in any of the 12-lead ECG readings. Additionally, the 3-lead ECG measurements showed no difference in maximum, minimum or mean RR intervals between snus-exposed and control groups, according to the study.
“Cigarette smoking during pregnancy has been linked to higher blood pressure in exposed children, but data have been inconsistent and continued exposure to second-hand smoke during childhood has complicated interpretations,” Felicia Nordenstam, MD, PhD, researcher in the division of pediatrics, departments of clinical science, intervention and technology and women’s and children’s health at the Karolinska Institute in Stockholm, told Healio. “By studying exposure to snus during pregnancy and breastfeeding we were able to exclude both the influence of combustion toxins from cigarette smoke and that of second-hand smoke exposure during childhood. Our results suggest that prenatal nicotine exposure per se may be associated with a higher blood pressure in the child.”
Researchers analyzed BP in children with snus exposure in fetal life (n = 21) and in tobacco-free controls (n = 19) at age 5 or 6 years. These children were the offspring of women who were recruited in Sweden from 2006 to 2011. According to the study, the women were classified during their first visit to the maternity center as snus users, smokers or tobacco-free controls following a questionnaire regarding their tobacco habits.
“We recommend all women to abstain from all types of tobacco and nicotine containing products during pregnancy,” Nordenstam told Healio. “Alternatives to traditional cigarettes may be better for the woman but are not safe for the child. This is important and needs to be addressed in the debate about e-cigarettes and nicotine products. Finding out how to help tobacco- and nicotine-using women stop their use during pregnancy is a major challenge without any easy answers yet.”
Useful model
“The strengths of this study are the unique nature of the nicotine exposure and the study design; the study of the effect of maternal snus use on childhood cardiovascular parameters is a useful model for the study of in utero nicotine exposure,” Hanano Watanabe, MD, MS, a pediatrician in the department of pediatrics at Columbia University Medical Center, and Neal S. Parikh, MD, MS, assistant professor of neurology at Weill Cornell Medicine, wrote in a related editorial. “A caveat is that children were exposed to variable amounts of nicotine after birth when breastfeeding, so the exposure to it is not strictly in utero. Additional important limitations include the small sample size, the presence of selection bias, and multiple statistical comparisons. These limitations may explain the dramatic effect size of a 5-mm Hg difference. Their findings require rigorous replication.” – by Scott Buzby
Disclosures: The study and editorial authors report no relevant financial disclosures.
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