Body mass index and the risk of stroke in men.
BACKGROUND
Although obesity is an established risk factor for coronary heart disease, its role as a risk factor for stroke remains controversial.


METHODS
Prospective cohort study among 21 414 US male physicians participating in the Physicians' Health Study. Incidence of total, ischemic, and hemorrhagic stroke was measured by self-report and confirmed by medical record review. We used Cox proportional hazards models to evaluate the association of body mass index (BMI), calculated as self-reported weight in kilograms divided by the square of the height in meters, with risk of total, ischemic, and hemorrhagic stroke.


RESULTS
During 12.5 years of follow-up, 747 strokes (631 ischemic, 104 hemorrhagic, and 12 undefined) occurred. Compared with participants with BMIs less than 23, those with BMIs of 30 or greater had an adjusted relative risk of 2.00 (95% confidence interval [CI], 1.48-2.71) for total stroke, 1.95 (95% CI, 1.39-2.72) for ischemic stroke, and 2.25 (95% CI, 1.01-5.01) for hemorrhagic stroke. When BMI was evaluated as a continuous variable, each unit increase of BMI was associated with a significant 6% increase in the adjusted relative risks of total (95% CI, 4%-8%), ischemic (95% CI, 3%-8%), and hemorrhagic stroke (95% CI, 1%-12%). Additional adjustment for hypertension, diabetes mellitus, and hypercholesterolemia slightly attenuated the risks for total and ischemic (relative risk, 4%; 95% CI, 2%-7%), but not hemorrhagic, stroke.


CONCLUSIONS
These prospective data indicate a significant increase in the relative risk of total stroke and its 2 major subtypes with each unit increase of BMI that is independent of the effects of hypertension, diabetes, and cholesterol. Because BMI is a modifiable risk factor, the prevention of stroke may be another benefit associated with preventing obesity in adults.
Kurth
Tobias
T
Brigham and Women's Hospital, Division of Preventive Medicine, 900 Commonwealth Ave East, Boston, MA 02215-1204, USA. tkurth@rics.bwh.harvard.edu
Gaziano
J Michael
JM
Berger
Klaus
K
Kase
Carlos S
CS
Rexrode
Kathryn M
KM
Cook
Nancy R
NR
Buring
Julie E
JE
Manson
JoAnn E
JE
D000367:Age Factors; D000368:Aged; D015992:Body Mass Index; D015331:Cohort Studies; D015897:Comorbidity; D006801:Humans; D008019:Life Style; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000175:diagnosis / Q000453:epidemiology*; D010820:Physicians; D015995:Prevalence; D011336:Probability; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012044:Regression Analysis; D012307:Risk Factors; D020521:Stroke / Q000175:diagnosis / Q000453:epidemiology*; D016019:Survival Analysis; D014481:United States / Q000453:epidemiology