A PROSPECTIVE STUDY OF BODY MASS INDEX, WEIGHT CHANGE, AND RISK OF
STROKE IN WOMEN
Obesity is an important cause of
coronary heart disease, diabetes mellitus, and hypertension. Whether obesity increases
risk of stroke remains controversial.
This prospective study examined the relationship of body mass index (BMI; weight in
kg/height in meters2) and weight change with risks of ischemic and hemorrhagic stroke.
Conclusion: Both obesity and weight gain in women are important risk factors for
ischemic stroke, but not hemorrhagic stroke.
STUDY
The Nurses Health Study entered over 116 000 women age 30-55 in 1976. All were free of
diagnosed coronary heart disease, stroke, and cancer.
Determined incidence of ischemic stroke and hemorrhagic stroke over 16 years.
RESULTS
Over 16 years, 866 total strokes were documented (including 403 ischemic and 269
hemorrhagic).
Women with BMI > 27 had significantly increased risk of ischemic stroke:
BMI Relative Risk compared with those with a BMI of less than 21.
27-29 1.75
29-32 1.90
>32 2.37
There was a nonsignificant inverse relation between obesity and hemorrhagic stroke with
the highest risk in the leanest BMI.
Weight gain from age 18 to 1976 was associated with an increased relative risk for
ischemic stroke: RR as compared with women who maintained stable weight.
Gain of 11-19 kg 1.69
Gain of 20+ kg 2.52
Weight gain was not associated with increased risk of hemorrhagic stroke.
DISCUSSION
Obesity was found to have different relationships to ischemic and hemorrhagic stroke.
The most obese women had a 2-fold increase in risk of ischemic stroke.
Adjustment for hypertension, diabetes, and elevated cholesterol accounted for most of
the risk observed, suggesting that these factors probably mediate the adverse effects of
obesity.
The inverse association for hemorrhagic stroke was strongest among hypertensives and
smokers.
Weight gain from age 18 to 1976 (ie, between age 18 and ages 30 to 55) was also a strong
predictor of ischemic stroke.
A number of studies in men also support a relationship between obesity and increased
risk of stroke.
CONCLUSION Both obesity and weight gain after age 18 in women are important risk
factors for ischemic stroke but not hemorrhagic stroke.
JAMA May 21, 1997; 277: 1539-45 Original investigation, first author from Brigham and
Womans Hospital, Boston, MA
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