Parental smoking and vascular damage in young adult offspring: is early life exposure critical? The atherosclerosis risk in young adults study.

OBJECTIVE Our purpose was to study the association between familial and particularly fetal tobacco smoke exposure and vascular damage in young adulthood. METHODS AND RESULTS From a cohort of 732 young adults, birth data were collected and in young adulthood ultrasound measurement of common carotid artery intima-media thickness (CIMT) was performed. Data on parental smoking were obtained by standardized questionnaires. Twenty-nine percent of the mothers smoked during pregnancy. Offspring of mothers who smoked had 13.4 microm thicker CIMT (95% CI: 5.5, 21.3; P=0.001) than offspring of mothers who did not smoke in pregnancy. Adjustment for known CIMT risk factors (participant's age, gender, BMI, pulse pressure, and LDL-cholesterol) yielded no change (9.4 microm, 95% CI: 1.9, 16.3, P=0.01) nor did adjustment for current smoking of parents (10.6 microm, 95% CI: 0.4 to 20.8, P=0.04), for participants' current smoking and pack-years (11.5 microm, 95% CI: 3.5 to 19.4, P=0.004) or for parental socioeconomic status (SES; 13.0 microm, 95% CI: 5.0, 21.1, P=0.002). Thicker CIMT was associated with exclusive paternal smoking in pregnancy, somewhat stronger with exclusive maternal smoking and strongest with both parents smoking (P (linear trend)=0.001). Offspring of particularly mothers who smoked an above median number of cigarettes in pregnancy had thicker CIMT than those smoking less than median or no cigarettes (P (linear trend) <0.0001). CONCLUSIONS Permanent vascular damage is partly attributable to familial tobacco smoke exposure, an association that might be initiated in gestation.