Associations of cigarette smoking with subclinical inflammation and atherosclerosis : ELSA-Brasil (The Brazilian Longitudinal Study of Adult Health)

Abstract

Background-—There is a need to identify sensitive biomarkers of early tobacco-related cardiovascular disease. We examined the association of smoking status, burden, time since quitting, and intensity, with markers of inflammation and subclinical atherosclerosis. Methods and Results-—We studied 14 103 participants without clinical cardiovascular disease in ELSA-Brasil (Brazilian Longitudinal Study of Adult Health). We evaluated baseline cross-sectional associations between smoking parameters and inflammation (highsensitivity C-reactive protein [hsCRP]) and measures of subclinical atherosclerosis (carotid intima–media thickness, ankle-brachial index, and coronary artery calcium [CAC]). The cohort included 1844 current smokers, 4121 former smokers, and 8138 never smokers. Mean age was 51.7 8.9 years; 44.8% were male. After multivariable adjustment, compared with never smokers, current smokers had significantly higher levels of hsCRP (b=0.24, 0.19–0.29 mg/L; P<0.001) and carotid intima–media thickness (b=0.03, 0.02–0.04 mm; P<0.001) and odds of ankle-brachial index ≤1.0 (odds ratio: 2.52; 95% confidence interval, 2.06–3.08; P<0.001) and CAC >0 (odds ratio: 1.83; 95% confidence interval, 1.46–2.30; P<0.001). Among former and current smokers, pack-years of smoking (burden) were significantly associated with hsCRP (P<0.001 and P=0.006, respectively) and CAC (P<0.001 and P=0.002, respectively). Among former smokers, hsCRP and carotid intima–media thickness levels and odds of ankle-brachial index ≤1.0 and CAC >0 were lower with increasing time since quitting (P<0.01). Among current smokers, number of cigarettes per day (intensity) was positively associated with hsCRP (P<0.001) and CAC >0 (P=0.03) after adjusting for duration of smoking. Conclusions-—Strong associations were observed between smoking status, burden, and intensity with inflammation (hsCRP) and subclinical atherosclerosis (carotid intima–media thickness, ankle-brachial index, CAC). These markers of early cardiovascular disease injury may be used for the further study and regulation of traditional and novel tobacco products.