Secondhand tobacco smoke exposure is an established risk factor for many medical conditions. It is estimated that about 2.5 million individuals have died due to issues related to secondhand smoke exposure since the 1960s. Secondhand smoke is particularly harmful in the pediatric population, with documented complications such as:
However, what is less well understood is the impact of secondhand smoke exposure on heart health and the development of atherosclerotic disease in the pediatric population. Increased carotid intima-media thickness (CIMT) is a well-validated risk factor for the development of atherosclerotic disease in adults. A systematic review, published in 2022, examined the relationship between environmental tobacco smoke exposure (ETS) and CIMT in healthy children and adolescents.
Following careful application of exclusion criteria and thorough assessment of quality, four studies were selected for review, including a total of 1,782 participants. Prenatal maternal smoking was determined by either parental reporting or delivery documentation. Postnatal ETS was assessed with questionnaires or review of serum cotinine levels, an objective marker of nicotine exposure, among children. CIMT in children was measured using high-resolution ultrasonography in all four studies.
Three studies revealed a significant relationship between postnatal ETS and CIMT in children. One study demonstrated a positive association between prenatal ETS and CIMT in the pediatric population. Two independent reviewers performed the review, and only one study of the four was considered high risk of bias. Of those three determined to be high quality, two demonstrated a statistically significant positive correlation between ETS and CIMT.
Limitations related to this review included a low number of studies, varying study methods, and some risk of bias. Of note, however, two studies that measured serum cotinine levels revealed a significant positive correlation between ETS and CIMT in a dose-response fashion, providing some evidence to support a causal relationship. This review demonstrates a potential link between secondhand tobacco smoke exposure and vascular damage in children, which should be taken into strong consideration. Prospective studies with a larger sample size should be carried out to better establish the relationship described in this review.