Waist circumference, body mass index, and risk for stroke in older people: a 15 year longitudinal population study of 70- year-olds

OBJECTIVES: To investigate waist circumference (WC) and body mass index (BMI) at age 70 as risk factors for stroke.

DESIGN: Cohort study of 70-year-olds with 15-year follow-up.

SETTING: Geriatric Medicine Department, Göteborg University, Sweden.

PARTICIPANTS: Two thousand two hundred eighty-seven (1,045 men; 1,242 women) 70-year-olds examined between 1971 and 1981 in Göteborg, Sweden.

MEASUREMENTS: Cox regression model was used to calculate relative risk (RR) and 95% confidence interval (CI) for first-ever stroke (fatal and nonfatal) in reference to the lowest quartiles of WC and BMI. Tests for trend were performed fitting WC and BMI in their original continuous form.

RESULTS: In men and women, RRs for stroke, in the highest WC quartile were 1.65 (95% CI = 1.08-2.51) and 1.31 (95% CI = 0.88-1.92), respectively, after adjustment for cohorts, smoking habit, coronary heart disease (CHD), diabetes mellitus, total cholesterol (TC), systolic blood pressure (SBP), and height at age 70. In men, RR for stroke in the highest BMI quartile (> or=28 kg/m2) was 1.68 (95% CI = 1.12-2.53) after adjustment for cohorts, smoking habits, CHD, diabetes mellitus, TC, and SBP at age 70. In women, adjusted RRs for stroke across the BMI quartiles were not significantly different. In men, population attributable fractions of stroke were 24.8% and 25.2% for the highest quartiles of WC and BMI, respectively.

CONCLUSIONS: High WC (> or =99 cm) and BMI (> or =28 kg/m2) are risks for stroke in older men but not in older women.