Sweden: Study on Perinatal Exposure to Smokeless Tobacco

A recent study published in the Journal of the American Heart Association focused on perinatal exposure to smokeless tobacco (i.e., nicotine), highlighting the long-term cardiovascular (CV) risks associated with it.

Felicia Nordenstam, Karolinska University Hospital, Stockholm, Sweden, and colleagues revealed that children exposed to high nicotine doses in utero demonstrated increased carotid artery stiffness and reduced carotid arterial strain during preschool age. They found no significant difference in carotid intima‐media thickness between the exposed and non-exposed children.

Study Findings

In the study of perinatal smokeless tobacco exposure, the researchers reported that preschool children with prenatal smokeless tobacco‐using mothers during pregnancy had a 41% higher arterial stiffness index compared with tobacco‐free controls. This finding adds to current recommendations that women should abstain from all forms of nicotine and tobacco products during pregnancy.

Increased intima‐media thickness and arterial stiffness can be seen as early as childhood and are tied to an increased risk of CV events in adult life. Dr. Nordenstam and the team hypothesized that exposure to prenatal smokeless tobacco (Swedish snus) without additional nicotine exposure after the breastfeeding period would be associated with increased arterial stiffness and intima‐media thickening in preschool children.

Methodology

To test the hypothesis, they conducted a longitudinal follow‐up cohort study comprising children aged 5 to 6 years exposed to high doses of nicotine in utero. Women exclusively using prenatal smokeless tobacco and unexposed controls were enrolled in early pregnancy (gestational age range, 6–12 weeks). Collection of exposure data was done during and after pregnancy with questionnaires from both groups.

The exposure group included only children of women using >48 mg of nicotine per day during their entire pregnancy. Outcomes were investigated in 40 healthy children (21 exposed to snus in utero). Ultrasonography of the common carotid artery was used to determine the carotid intima‐media thickness and calculate the arterial stiffness index from the relationship between pulsatile changes in arterial diameter and arterial pressure.

Key Findings

• Children exposed to prenatal smokeless tobacco in fetal life had higher carotid stiffness (median 4.1 versus 2.9) than tobacco‐free controls.
• Carotid strain (relative diameter change) was lower in children exposed to snus (mean 16% versus 21%) than in controls.
• Carotid intima‐media thickness did not differ significantly between children exposed to snus and controls.

"Preschool children exposed to snus in utero exhibit stiffer carotid arteries compared to unexposed children," the researchers wrote. "Although these changes are asymptomatic during childhood, they may have implications for future follow‐up and risk of CV events in adult life."

Reference

The study titled, "Arterial Stiffness and Carotid Intima‐Media Thickness in Children Exposed to Smokeless Tobacco in Fetal Life," was published online in the Journal of the American Heart Association.

DOI: https://doi.org/10.1161/JAHA.123.032384