Exposure to parental smoking early in life associated with greater carotid IMT in adulthood

Gall S, Huynh QL, Magnussen CG, et al.,
Eur Heart J. 2014 Mar 4. [Epub ahead of print]

Background

Passive exposure to cigarette smoke has been shown to affect vascular health, including impaired endothelial function [1,2], arterial stiffness [3] and greater arterial intima-media thickness (IMT)[2,4]. The largest source of passive smoke is parental smoking.
It has recently been demonstrated that exposure to parental smoking in childhood or adolescence is associated with lower brachial artery flow-mediated dilatation (FMD) in adulthood, independent of own smoking status and traditional cardiovascular (CV) risk factors [5]. The current study examined the role of exposure to parental smoking in childhood or adolescence on carotid IMT in adulthood, using the Cardiovascular Risk in Young Finns Study (YFS) cohort [6] and the Childhood Determinants of Adult Health (CDAH) cohort [7], with follow-up periods of up to 25 years.

Main results

• Exposure to both parents smoking earlier in life was associated with greater carotid IMT in adulthood in pooled analyses (mean carotid IMT: 0.653 vs. 0.637 with no smoking parents, P=0.001), as well as in cohort-specific analyses. This association was maintained after adjustment for confounders in childhood and adulthood (0.652 vs. 0.637, P=0.003).
• Having one smoking parent was not associated with carotid IMT in adulthood in pooled analyses (mean carotid IMT: 0.638 with either parent smoking vs. 0.637 with none smoking, P=0.729).
• Adult smoking status did not modify the association between parental smoking in childhood and adult carotid IMT.
• Greater exposure to parental smoking (based on number of smokers) was associated with a significantly greater carotid IMT in adulthood, in both cohorts. This association was largely unaffected by adjustment for age and sex, sociodemographic and health factors at baseline and follow-up, and CV risk factors at follow-up.

Conclusion

Two independent cohorts reveal that adults who were exposed to both parents smoking in childhood or adolescence, had greater carotid IMT than those with one or no parent who smoked. This effect was largely independent of CV risk factors, indicating an irreversible impact of smoke exposure on arterial health later in life. Considering this pervasive effect of cigarette smoke on endothelial function later in life, reducing young people’s exposure to tobacco smoke is a public health priority.

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