CIGARETTE-SMOKING AND PERIPHERAL ARTERIAL OCCLUSIVE DISEASE

Background. The importance of cigarette smoking in the etiology of per ipheral arterial occlusive disease is well known, but there have been few studies that have quantified this relationship Methods. A case-con trol study design was used in which the case subjects were men with a history of claudication for at least 1 year and abnormal findings on n oninvasive blood flow studies or on arteriography; control subjects we re men attending the same hospital for conditions other than cancer, w ith no history of cancer or vascular disease and with a normal ankle-b rachial index. Case and control subjects were interviewed by a trained nurse interviewer using a pilot-tested questionnaire. Current smoking status was confirmed by serum cotinine level estimation. Univariate o dds ratios for smoking and other potential risk factors were calculate d, and their significance was tested by comparison with the chi-square d distribution. Logistic regression analysis was used to adjust the ef fect of smoking for confounding variables, and the regression equation was used to estimate the proportion of disease attributable to smokin g. Results. Of the patients approached, 94% of the eligible case subje cts and 93% of the eligible control subjects agreed to participate. Re cruitment ended with 102 cases of peripheral arterial occlusive diseas e and 99 controls. Most of the control subjects were attending clinics for other surgical specialties. Compared with men who had never smoke d the relative risk was 7 for exsmokers and 16 for current smokers (p < 0.001). The relative risk increased directly with the lifetime numbe r of cigarettes smoked, the chi-squared test for trend being highly si gnificant (p < 0.001). Age, lipoprotein concentration, body mass index , and history of hypertension or heart disease were also significant r isk factors. Conclusions. After adjustment for confounding variables t he estimate of the fraction of disease attributable to smoking was 76% .