Body mass index. An independent predictor of cataract.
OBJECTIVE
To examine whether body mass index is an independent predictor of cataract. (Body mass index is a standardized measure defined as weight in kilograms divided by the square of the height in meters.)


METHODS
Prospective cohort study, with 5 years of follow-up.


METHODS
A total of 17,764 US male physicians participating in the Physicians' Health Study, aged 40 to 84 years, who were free of cataract, myocardial infarction, stroke, and cancer at baseline and reported complete information about body mass index and other cataract risk factors.


METHODS
Incident cataract, defined as a self-report, confirmed by medical record review, first diagnosed after randomization, age-related in origin, and responsible for a decrease in best corrected visual acuity to 20/30 or worse.


RESULTS
Incident cataract occurred during follow-up in 370 participants. In proportional hazards models that adjusted for potential confounding variables, body mass index had a strong, graded relationship with risk of cataract. Relative to those with body mass index less than 22, relative risks (95% confidence intervals) associated with body mass index of 22 to less than 25, 25 to less than 27.8, and 27.8 or more were 1.54 (1.04 to 2.27), 1.46 (0.98 to 2.20), and 2.10 (1.35 to 3.25), respectively. Relative to any given level of body mass index, a 2-unit higher level predicted a 12% increase in risk of cataract (95% confidence interval, 5% to 19%). Higher body mass index was especially strongly related to risk of posterior subcapsular and nuclear sclerotic cataracts and was also significantly related to risk of cataract extraction.


CONCLUSIONS
In a prospective cohort study of apparently healthy men, higher body mass index, a potentially modifiable risk factor, was a determinant of cataract. The leanest men had the lowest rates, consistent with experimental evidence that restriction of energy intake slows development of cataract. Although precise mechanisms are unclear, the effect of body mass index on cataractogenesis is apparently independent of other risk factors, including age, smoking, and diagnosed diabetes.
Glynn
R J
RJ
Department of Medicine, Brigham and Women's Hospital, Boston, Mass, USA.
Christen
W G
WG
Manson
J E
JE
Bernheimer
J
J
Hennekens
C H
CH
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001241:Aspirin / Q000627:therapeutic use; D001824:Body Constitution; D015992:Body Mass Index; D002318:Cardiovascular Diseases / Q000517:prevention & control; D002338:Carotenoids / Q000627:therapeutic use; D002386:Cataract / Q000453:epidemiology* / Q000209:etiology; D015331:Cohort Studies; D004311:Double-Blind Method; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000517:prevention & control; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D014481:United States / Q000453:epidemiology; D019207:beta Carotene
D019207:beta Carotene; D002338:Carotenoids; D001241:Aspirin