Associations of Tobacco Smoking with Impaired Endothelial Function: The Circulatory Risk in Communities Study (CIRCS)

Aims: Smoking impairs endothelial function as an acute effect. However, few population-based studies have examined the association between smoking status and endothelial function or the dose-response and duration- response association of smoking with endothelial function. We examined whether smoking habits were associated with impaired endothelial function depending on smoking dose and duration. Methods: We conducted a cross-sectional study of 910 men and women aged 30–79 years from 2013 to 2016. Statistical analyses of the data were conducted between 2016 and 2017. Endothelial function was assessed by brachial artery flow-mediated dilation (FMD) measurement. Low FMD was defined in two ways as the cutoff point based on the lowest quartile of %FMD (< 5.1%) and median of %FMD (< 6.8%), regarding as impaired endothelial function. We investigated the smoking status in terms of cigarettes consumed per day and the duration of smoking. Results: Heavy and chronic smokers were associated with a high prevalence of impaired endothelial function. Those associations did not change substantially after adjustment for other cardiovascular risk factors. Among all participants, the multivariable-adjusted ORs (95% CIs) of low FMD (< 5.1%) with reference to never smokers were 2.23 (1.00–5.14) for current heavy smokers of ≥ 30 cigarettes per day, 1.83 (1.04–3.20) for heavy smokers of ≥ 40 pack-years, and 2.16 (1.15–4.06) for chronic smokers of ≥ 40 years. For low FMD (< 6.8%) those values was 2.17 (1.01–5.05), 1.70 (1.01–2.86), and 1.98 (1.07–3.69), respectively. Conclusions: Similar associations were observed among only men. Heavy or long-term tobacco smoking may induce impaired endothelial function.