The association of Tabacco smoke with subclinical atherosclerosis and atherosclerosis progression is stronger in women than in men

Background: That smoking predisposes to cardiovascular disease is not disputed. The reduction in male smokers has been a public health achievement; unfortunately the number of women smokers (initially lower than men) has not declined to the same extent, but is even increasing. In the present study we investigated the association of pack-years or cigarettes/day with both baseline carotid IMT (C-IMT) and the fastest C-IMT progression in 1694 men and 1893 women (age 54-79 yr) of the IMPROVE Study cohort that includes subjects at high risk of cardiovascular disease of five European countries. Methods: Baseline mean and maximum IMT of the left and right common carotids, bifurcations and internal carotid arteries and the fastest IMT-progression (15 months of follow up) detected in the whole carotid tree regardless of its location were computed and used in the statistical analyses. Associations were assessed by multivariable analysis adjusting for conventional cardiovascular risk factors, education and recruiting centre. Results: Pack-years, a lifelong index of tobacco exposure, significantly associated with baseline C-IMT in both genders. However, the estimated C-IMT increase for each pack-year was more than double in women than in men (3.7±0.7 vs. 1.5±0.5 µm) with a significant gender × dose interaction (P=0.01). Moreover, the estimated increase in the fastest C-IMT progression associated with a unit of cigarettes/day, an index of daily dose of tobacco exposure, was more than five-fold in women than in men (5.5±1.3 vs. 1.0±1.3 µm/yr), (P interaction =0.008). Conclusions. The effects of tobacco smoking on cross-sectional subclinical atherosclerotic burden, and on atherosclerosis progression appear to be more harmful in women than in men, prompting studies on gender specific mechanisms and development of preventive actions expressly oriented to women.