Parents' Smoking May Cause Vascular Damage in Children

From Medscape Medical News Laurie Barclay, MD December 26, 2011 — Parental smoking during pregnancy may cause vascular damage when the children reach 5 years of age, according to the results of a birth cohort study published online December 26 and in the January 2012 print issue of Pediatrics. "Smoking during pregnancy has been related to thicker carotid intima media thickness in young adults, and this was also shown in neonates," write Caroline C. Geerts, MD, from the Julius Center for Health Sciences and Primary Care and University Medical Center Utrecht in the Netherlands and colleagues. "The relation between smoke exposure in early life, the prenatal period in particular, and the vascular development of young children is largely unknown." To evaluate the association between parental smoking during pregnancy and subsequent vascular characteristics in their children, the investigators used data from the birth cohort enrolled in the Wheezing Illnesses Study Leidsche Rijn (WHISTLER)-Cardio study. At 5 years of age, 259 participants underwent ultrasonographic measurement of carotid artery intima-media thickness (CIMT) and arterial wall distensibility. Parental smoking data were also updated. After adjustment for the child's age and sex, maternal age, and breast-feeding, children of mothers who had smoked throughout pregnancy had more vascular damage than children of mothers who did not smoke during pregnancy. CIMT was 18.8 μm thicker in the former group (95% confidence interval [CI], 1.1 - 36.5; P = .04), and distensibility was 15% lower (95% CI, −0.3 to −0.02; P = .02). Children of mothers who smoked after pregnancy, but not during pregnancy, did not have these adverse effects on CIMT and distensibility. If both parents smoked during pregnancy, the associations were even stronger than with only maternal smoking: CIMT was 27.7 μm thicker (95% CI, 0.2 - 55.3), and distensibility was 21% lower (95% CI, −0.4 to −0.03). "This study is the first to show that the effect of smoking during pregnancy on the vasculature of children is (still) visible at the age of 5 years," the study authors write. "Pregnancy appears to be the critical period for this damage to occur." Limitations of this study include slightly different profiles in participants than in nonparticipants, lack of cotinine measurements at birth, and reliance on parental self-report of smoking. "In view of the early origins of cardiovascular disease, preventive measures against smoking should be specifically directed at the gestational period," the study authors conclude. The Netherlands Organization for Health Research and Development supported the WHISTLER birth cohort. The University Medical Center Utrecht supported WHISTLER-Cardio. The authors have disclosed no relevant financial relationships. Pediatrics. Published online December 26, 2011. Abstract