Cigarette smoking and the development and progression of aortic atherosclerosis. A 9-year population-based follow-up study in women.

BACKGROUND Cigarette smoking has been recognized as an important risk factor for cardiovascular disease in men and women. Whether the increased risk results from an atherogenic effect of smoking is still debated. We examined the relation between cigarette smoking and atherosclerotic changes in the abdominal aorta. METHODS AND RESULTS The association between cigarette smoking and atherosclerotic changes in the abdominal aorta was examined in a population-based cohort of 758 women, initially aged 45 to 64 years. All women were examined radiographically for calcified deposits in the abdominal aorta, which have been shown to represent intimal atherosclerosis. After 9 years of follow-up, atherosclerotic changes, indicating development or progression of plaques, could be demonstrated in 37% of women. A direct association was found between atherosclerotic change and number of cigarettes smoked per day. Compared with women who had never smoked, the relative risks of those who smoked 1 to 9, 10 to 19, and 20 or more cigarettes per day were 1.4 (95% confidence interval, 1.0 to 2.0), 2.0 (1.6 to 2.5), and 2.3 (1.8 to 3.0), respectively, after adjustment for age and other cardiovascular risk factors. Associations of atherosclerotic change with inhaling habit and duration of smoking were borderline significant after number of cigarettes smoked per day was taken into account. Among former smokers, the risk decreased with increasing duration of stopping but a significant excess risk was still observed after 5 to 10 years since quitting (relative risk, 1.6; 95% confidence interval, 1.1 to 2.2). CONCLUSIONS These follow-up data support the evidence for an effect of cigarette smoking on atherosclerosis. The findings suggest that the rate of atherosclerotic change may be reduced by cessation of smoking, but a residual effect appears to be present for at least 10 years.