A POPULATION-BASED MODEL OF RISK-FACTORS FOR ISCHEMIC STROKE - ROCHESTER, MINNESOTA

The medical record linkage system for the Rochester Epidemiology Proje ct provided the means to identify 1,444 incidence cases of ischemic st roke and age- and sex-matched controls from the population from 1960 t o 1984 to conducts case-control study nested in the population. A mult iple logistic-regression model permitted the estimation of odds ratios of ischemic stroke for each risk factor while adjusting for confoundi ng variables. The final model, in addition to age and date of stroke, included transient ischemic attacks, hypertension, current smoking, at rial fibrillation, ischemic heart disease, mitral valve disease (other than prolapse), and diabetes mellitus. The process identified interac tions showing that ischemic stroke incidence for persons with transien t ischemic attacks was higher in women than in men and that the risk d ecreased with increasing age; that the risk of stroke with hypertensio n and also with current cigarette smoking decreased with increasing ag e; and that the risk of ischemic stroke with intermittent or persisten t atrial fibrillation was similar when hypertension was present, but w ithout hypertension the risk of stroke was more than seven times great er with persistent-than with intermittent atrial fibrillation. None of the odds ratios differed over the five quinquennia of the study, and no effect of antihypertensive treatment on stroke incidence could be d emonstrated in the population.