Objective To examine the associations between frequent exposure to tobacco smoke, arterial changes related to early atherosclerosis and serum lipid profile in adolescents.
Methods Healthy 13-year-old adolescents from the atherosclerosis prevention trial (STRIP) were studied. Maximum carotid (cIMT) and aortic intima-media thickness (aIMT), and brachial artery flow-mediated dilation (FMD) were measured in 494 adolescents using high resolution ultrasound. Serum lipid, lipoprotein, and apolipoprotein (Apo) values were determined using standard methods. Exposure to tobacco smoke was measured annually between ages 8 and 13 years using serum cotinine concentrations, analyzed with gas chromatography. To define longitudinal exposure, cotinine values of children having serum cotinine measured 2 to 6 times during follow-up were averaged and divided into tertiles (exposure groups): low (n=160), intermediate (n=171), and high (n=163).
Results Adolescents with higher longitudinal exposure to tobacco smoke had increased cIMT (exposure groups [mean±SD]: low 0.502±0.079mm, intermediate 0.525±0.070mm, high 0.535±0.066mm; p<0.001), and increased aIMT (exposure groups: low 0.527±0.113mm, intermediate 0.563±0.139mm, high 0.567±0.126mm; p=0.004). The FMD decreased when cotinine level increased (exposure groups: low 10.43±4.34%, intermediate 9.78±4.38%, high 8.82±4.14%; p=0.001). These associations were unchanged after adjusting for traditional atherosclerosis risk factors. Moreover, ApoB (p=0.004), ApoB/ApoA-I ratio (p=0.013), and triglycerides (p=0.037) increased with increase in cotinine level.
Conclusions Frequent exposure to tobacco smoke is independently associated with arterial changes of preclinical atherosclerosis and increased ApoB levels among healthy adolescents.