Body mass index and risk of stroke and myocardial infarction in a relatively lean population: meta-analysis of 16 Japanese cohorts using individual data.
BACKGROUND
The association of overweight/obesity with the incidence of cardiovascular diseases, especially stroke, has not been comprehensively examined in relatively lean populations in which stroke is more prevalent than coronary heart disease.


RESULTS
Pooled individual data from 16 Japanese cohorts comprising 45 235 participants ages 40 to 89 years without previous history of cardiovascular disease were studied. During follow-up, 1113 incident strokes and 190 myocardial infarctions were identified. At baseline, mean ages of men and women were 55.4 and 56.5 years and mean body mass indices (BMI) were 23.0 and 23.4 kg/m(2), respectively. Compared with those with BMI <21.0, incidence rates of cerebral infarction in subjects with BMI ≥ 27.5 were significantly elevated in both men (hazard ratio, 1.81; 95% confidence interval [CI], 1.28 to 2.56) and women (hazard ratio, 1.65; 95% CI, 1.23 to 2.21), adjusted for age, smoking, and drinking habit. Incidence of cerebral hemorrhage was also associated positively with BMI in both men (hazard ratio, 2.51; 95% CI, 1.21 to 5.20) and women (hazard ratio, 1.98; 95% CI, 1.12 to 3.52). Adjustment for systolic blood pressure, a mediating factor, significantly attenuated most BMI association with stroke in both sexes. For myocardial infarction, the hazard ratio was 3.16 (95% CI, 1.66 to 6.01) for BMI 27.5 or greater versus less than 21.0 only in men, which appeared partly mediated by total cholesterol and SBP.


CONCLUSIONS
Overweight/obesity was associated with an increased risk of cerebral infarction and hemorrhage in men and women and myocardial infarction in men. Weight control may have the potential to prevent both stroke and myocardial infarction in Japan.
Yatsuya
Hiroshi
H
Department of Public Health, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Japan. yatsuya@gmail.com
Toyoshima
Hideaki
H
Yamagishi
Kazumasa
K
Tamakoshi
Koji
K
Taguri
Masataka
M
Harada
Akiko
A
Ohashi
Yasuo
Y
Kita
Yoshikuni
Y
Naito
Yoshihiko
Y
Yamada
Michiko
M
Tanabe
Naohito
N
Iso
Hiroyasu
H
Ueshima
Hirotsugu
H
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D002543:Cerebral Hemorrhage; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D007564:Japan; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000453:epidemiology* / Q000503:physiopathology; D009765:Obesity / Q000453:epidemiology* / Q000503:physiopathology; D012306:Risk; D012737:Sex Factors; D020521:Stroke / Q000453:epidemiology* / Q000503:physiopathology; D013851:Thinness