Recreational physical activity and risk of epithelial ovarian cancer.
BACKGROUND
Physical activity may influence ovarian cancer risk through hormonal, inflammatory, or immune-mediated processes or by suppressing ovulation. In a population-based case-control study of epithelial ovarian cancer, we assessed risk associated with recreational physical activity with a focus on characterizing risk within histologic subtypes.


METHODS
Information was collected during in-person interviews with 812 women with ovarian cancer diagnosed in western Washington State from 2002-2005 and 1,313 controls. Logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs). Exercise was assessed according to the average hours and metabolic equivalent (MET)-hours per week and the number of years in which regular recreational activity occurred.


RESULTS
Relative to women who reported no regular exercise throughout adulthood, the overall risk of invasive, but not borderline, ovarian cancer was reduced among more active women. Reductions in risk of invasive disease were most evident among women with the greatest frequency of high-intensity activity during adulthood. For serous invasive cancer, women in the uppermost category of MET-hours per week of recreational activity in adulthood had 60% the risk of inactive women (95% CI 0.4-0.9), whereas this level of activity was associated with more than a doubling in risk of endometrioid and clear cell invasive tumors.


CONCLUSIONS
Our findings are compatible with an overall reduction in risk of invasive epithelial ovarian cancer associated with recreational activity but suggest that this association may differ in women with different histologic types of disease. Inconsistent findings across studies that have considered histologic type indicate that this issue is not yet resolved.
Rossing
Mary Anne
MA
Program in Epidemiology, Fred Hutchinson Cancer Research Center, PO Box 19024, Seattle, WA 98108-1024, USA. mrossing@fhcrc.org
Cushing-Haugen
Kara L
KL
Wicklund
Kristine G
KG
Doherty
Jennifer A
JA
Weiss
Noel S
NS
D000328:Adult; D000368:Aged; D016001:Confidence Intervals; D004847:Epithelial Cells / Q000473:pathology; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D007407:Interviews as Topic; D016015:Logistic Models; D008875:Middle Aged; D016017:Odds Ratio; D010051:Ovarian Neoplasms / Q000473:pathology / Q000503:physiopathology* / Q000517:prevention & control*; D011998:Recreation / Q000502:physiology; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors; D014861:Washington