Body mass and colorectal cancer risk in the NIH-AARP cohort.
In most studies, body mass index (BMI) has been associated with increased risk of colorectal or colon cancer in men, but the relation is weaker and less consistent for women, possibly because of interactions with age or hormone replacement therapy. The authors examined the relation between BMI and colorectal cancer incidence in a large, prospective US cohort of 307,708 men and 209,436 women from the NIH-AARP Diet and Health Study. During follow-up of the cohort from 1995 to 2000, 2,314 cases of colorectal cancer were observed in men and 1,029 in women. BMI was related to increased risk of incident colon cancer, but not rectal cancer, for both men and women. For men, relative risks of colon cancer for a BMI of 18.5-<23, 23-<25, 25-<27.5, 27.5-<30, 30-<32.5, 32.5-<35, 35-<40, and > or = 40 kg/m(2) were 1.0 (referent), 1.11, 1.22, 1.44, 1.53, 1.57, 1.71, and 2.39, respectively (95% confidence interval: 1.59, 3.58; p-trend < 0.0005). Corresponding relative risks for women were 1.0, 1.20, 1.29, 1.31, 1.28, 1.13, 1.46, and 1.49 (95% confidence interval: 0.98, 2.25; p-trend = 0.02). BMI was related to colon cancer risk for younger (aged 50-66 years) but not older (aged 67-71 years) women. The association was not modified by hormone replacement therapy in women or physical activity in men or women.
Adams
Kenneth F
KF
Nutritional Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Rockville, MD, USA. adamske@mail.nih.gov
Leitzmann
Michael F
MF
Albanes
Demetrius
D
Kipnis
Victor
V
Mouw
Traci
T
Hollenbeck
Al
A
Schatzkin
Arthur
A
D017677:Age Distribution; D000368:Aged; D015992:Body Mass Index; D015331:Cohort Studies; D015179:Colorectal Neoplasms / Q000209:etiology* / Q000517:prevention & control; D016001:Confidence Intervals; D005260:Female; D020249:Hormone Replacement Therapy; D006801:Humans; D015994:Incidence; D008019:Life Style; D008297:Male; D009765:Obesity / Q000150:complications*; D012042:Registries; D012307:Risk Factors; D017678:Sex Distribution; D011795:Surveys and Questionnaires; D014481:United States / Q000453:epidemiology