Physical activity and endometrial cancer in a population-based case-control study.
BACKGROUND
Published studies of physical activity, BMI, and endometrial cancer risk show conflicting results and many do not report on reliability or validity of physical activity questionnaires.


METHODS
We collected physical activity data on 667 incident cases of endometrial cancer and 662 age-matched controls. Interview-administered questionnaires, collecting demographic and lifestyle information, including a validated questionnaire for physical activity. We performed unconditional logistic regression to examine the relationship between moderate- to vigorous-intensity sports/recreational physical activity (MV PA), sit time, and endometrial cancer risk.


RESULTS
Compared to women reporting 0 metabolic equivalent (MET) hours per week of MV PA, those who reported 7.5 MET h/wk or more had a 34% lower endometrial cancer risk (odds ratio (OR) = 0.66, 95% CI 0.50-0.87) after adjusting for risk factors including BMI. Those women sitting more than 8 h per day had a 52% increased odds (95% CI 1.07-2.16) of endometrial cancer compared to those sitting less than 4 h per day. We created a composite measure of physical activity and BMI and found that women with a BMI <25 and activity levels ≥7.5 MET h/wk had a 73% lower endometrial cancer risk (OR = 0.27, 95% CI 0.18-0.39) compared with the reference group of overweight (BMI ≥25) and sedentary (MET h/wk = 0).


CONCLUSIONS
Our data support an inverse, independent association between physical activity and endometrial cancer risk after adjusting for BMI and other risk factors.
Department of Chronic Disease Epidemiology, Yale School of Public Health, New Haven, CT 06520-8034, USA.
Hannah
H
Arem
Melinda L
ML
Irwin
Yang
Y
Zhou
Lingeng
L
Lu
Harvey
H
Risch
Herbert
H
Yu
D000328:Adult; D000368:Aged; D018269:Carcinoma, Endometrioid / Q000453:epidemiology* / Q000209:etiology; D016022:Case-Control Studies; D016889:Endometrial Neoplasms / Q000453:epidemiology* / Q000209:etiology; D005260:Female; D006801:Humans; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D011153:Population; D011998:Recreation / Q000502:physiology; D015203:Reproducibility of Results; D012307:Risk Factors; D011795:Surveys and Questionnaires / Q000592:standards