title: Oral contraceptive use and risk of breast carcinoma in situ.
abstract: There is some indication that oral contraceptive use may be associated with a small increase in risk of invasive breast cancer; however, oral contraceptive use in relation to breast carcinoma in situ (BCIS) has rarely been studied. We investigated oral contraceptive use in relation to risk of BCIS in a large population-based case-control study. Female residents of Wisconsin, Massachusetts, and New Hampshire aged 20 to 74 years with a new diagnosis of BCIS (n=1,878) were identified from statewide tumor registries in 1997 to 2001. Age-matched female controls (n=8,041) were randomly selected from population lists. Information on oral contraceptive use and other risk factors was collected during structured telephone interviews. Odds ratios (OR) and 95% confidence intervals (95% CI) were estimated using logistic regression. In multivariate models, ever use of oral contraceptives was associated with a small and marginally significant increase in BCIS overall (OR, 1.11; 95% CI, 0.99-1.25) and for ductal carcinoma in situ (OR, 1.15; 95% CI, 1.01-1.31). No strong associations were detected according to age started, duration, time since first or last use, or oral contraceptive use relative to the first full-term pregnancy. The slightly increased risk of BCIS seemed limited to former users (OR, 1.13; 95% CI, 1.00-1.27) and women without a family history of breast cancer (OR, 1.16; 95% CI, 1.01-1.32 for ever versus never use). Consistent with invasive breast cancer, these results suggest that oral contraceptive use is at most a minor contributor to BCIS risk.
authors.affiliation: University of Wisconsin Paul P. Carbone Comprehensive Cancer Center, University of Wisconsin, Madison, WI 53726, USA.
authors.forename: Hazel B
authors.initials: HB
authors.lastname: Nichols
authors.forename: Amy
authors.initials: A
authors.lastname: Trentham-Dietz
authors.forename: Kathleen M
authors.initials: KM
authors.lastname: Egan
authors.forename: Linda
authors.initials: L
authors.lastname: Titus-Ernstoff
authors.forename: John M
authors.initials: JM
authors.lastname: Hampton
authors.forename: Polly A
authors.initials: PA
authors.lastname: Newcomb
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000139:chemically induced / Q000453:epidemiology* / Q000378:metabolism / Q000473:pathology; D002278:Carcinoma in Situ / Q000145:classification / Q000453:epidemiology* / Q000378:metabolism / Q000473:pathology; D016022:Case-Control Studies; D003276:Contraceptives, Oral / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007407:Interviews as Topic; D008327:Mammography; D008875:Middle Aged; D017584:Reproductive History; D012307:Risk Factors; D014481:United States / Q000453:epidemiology; D015430:Weight Gain
chemical_list: D003276:Contraceptives, Oral