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.