EPIDEMIOLOGY OF INTERMITTENT CLAUDICATION IN MIDDLE-AGED MEN

Intermittent claudication, myocardial infarction, and angina share man y epidemiologic and biologic features. Yet few large cohort studies de scribing the prevalence, incidence, and risk factors for intermittent claudication have been done. The authors evaluated intermittent claudi cation in 10,059 Israeli men aged 40-65 years, of whom 8,343 were free of coronary heart disease and symptoms of peripheral vascular disease ; this latter group was followed for 5 years from 1963 to 1968. Preval ent and incident cases of intermittent claudication were defined by th e London School of Hygiene Cardiovascular Disease Questionnaire, and a ll cardiovascular disease risk factor evaluations were standardized. B aseline prevalence was 27.0/1,000 (211/10,029). A total of 360 previou sly healthy men developed intermittent claudication for a crude 5-year incidence rate of 43.1/1,000 (360/8,343) or a crude annual incidence of 8.6/1,000. Following univariate analysis with demographic, physiolo gic, psychosocial, and other cardiovascular disease variables, logisti c regression was used to identify risk factors for intermittent claudi cation. These were the following: >20 cigarettes per day, odds ratio ( OR) = 2.02, 95% confidence interval (CI) 1.54-2.66; serum cholesterol (50-mg/dl difference), OR = 1.35, 95% CI 1.18-1.54; 11-20 cigarettes p er day, OR = 1.69, 95% CI 1.24-2.30; anxiety (high vs. low), OR = 1.85 , 95% CI 1.29-2.65; socioeconomic status, OR = 1.82, 95% CI 1.26-2.64; and diabetes, OR = 1.85, 95% CI 1.25-2.75. Other significant predicto rs of smaller magnitude included in the regression were age, psychosoc ial coping factors, Quetelet's index, and exsmoking. The risk factors for intermittent claudication were a blend of those related to myocard ial infarction (smoking, cholesterol, diabetes, but not hypertension) and others related to angina pectoris but not to myocardial infarction (stress and coping variables). There is reason to believe that preven ting or modifying these factors will prove effective in altering the n atural history and clinical outcomes of peripheral vascular disease as shown in other forms of atherosclerosis.