Comparison of risk factors for stroke incidence and stroke mortality in 20years of follow-up in men and women in the Renfrew/Paisley study in Scotland

Background and Purpose-The aim of this study was to relate risk factors in middle-aged men and women to stroke incidence (defined by having a hospital discharge with a main diagnosis of stroke) and compare this with the assoc iations between risk factors and stroke mortality. Methods-In the early to mid-1970s, when they were 45 to 64 years of age, 70 52 men and 8354 women from the Renfrew/Paisley prospective cohort study in Scotland were screened. Risk factors measured included blood pressure, bloo d cholesterol and glucose, respiratory function, cardiothoracic ratio, smok ing habit, height, body mass index, preexisting coronary heart disease, and diabetes. These were related to stroke incidence over 20 years of follow-u p. Results-Diastolic and systolic blood pressure, smoking, cardiothoracic rati o, preexisting coronary heart disease, and diabetes were positively related to stroke incidence for men and women, whereas adjusted FEV1 (forced expir atory volume in 1 second) and height were negatively related. Cholesterol w as not related to stroke. Glucose for nondiabetic subjects had a U-shaped r elationship with stroke. Body mass index was not clearly related to stroke, although participants with the highest body mass index had the highest str oke rate. Former smokers had similar stroke rates to never-smokers. Tests b etween the associations of risk factors and stroke incidence revealed these were not statistically different from the associations with stroke mortali ty. Conclusions-The risk factors had a similar effect on stroke incidence as on stroke mortality. Epidemiological studies with information on stroke morta lity are likely to give results applicable to stroke incidence.