A PROSPECTIVE-STUDY OF REPRODUCTIVE FACTORS, ORAL-CONTRACEPTIVE USE, AND RISK OF COLORECTAL-CANCER

Citation
Me. Martinez et al., A PROSPECTIVE-STUDY OF REPRODUCTIVE FACTORS, ORAL-CONTRACEPTIVE USE, AND RISK OF COLORECTAL-CANCER, Cancer epidemiology, biomarkers & prevention, 6(1), 1997, pp. 1-5
Citations number
52
Categorie Soggetti
Public, Environmental & Occupation Heath
ISSN journal
10559965
Volume
6
Issue
1
Year of publication
1997
Pages
1 - 5
Database
ISI
SICI code
1055-9965(1997)6:1<1:APORFO>2.0.ZU;2-Q
Abstract
To explore the roles of reproductive factors and oral contraceptive us e in the etiology of colorectal cancer, we examined incident cases of colorectal cancer (n = 501) that occurred during 1,012,280 person-year s of follow-up between 1980 and 1992 in the Nurses' Health Study. The women completed mailed, self-administered questionnaires every 2 years to update information on the risk factors and major medical events, I n multivariate analysis, the relative risk (RR) of colorectal cancer a mong women who experienced menarche at age 14 or older was 0.83 (95% c onfidence interval (CI) = 0.64-1.08) compared with women who had menar che at age 13; women whose menarche occurred under age 12 were at high er risk (RR = 1.22; 95% CI = 0.96-1.55, P for trend = 0.01), Compared with women whose first pregnancy was before age 24, the risk for color ectal cancer was significantly increased among women whose first pregn ancy was at age 30 or older (RR = 1.57; 95% CI = 1.15-2.14; P for tren d = 0.02), No important associations were seen for parity or age at me nopause. Women who used oral contraceptives for 96 months or longer ha d a 40% lower risk of developing colorectal cancer (RR = 0.60; 95% CI = 0.40-0.89; P for trend = 0.02) compared with women who never used or al contraceptives, These prospective data suggest that a later age at menarche and use of oral contraceptives may reduce risk of colorectal cancer, whereas women with a later age at first pregnancy may have a h igher risk.