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A case–control study of breast cancer in relation to the use of steroid contraceptive agents
Author(s) -
Ellery Christine,
Berry Geoffrey,
MacLennan Robert,
Shearman Rodney P.
Publication year - 1986
Publication title -
medical journal of australia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.904
H-Index - 131
eISSN - 1326-5377
pISSN - 0025-729X
DOI - 10.5694/j.1326-5377.1986.tb128351.x
Subject(s) - medicine , menarche , relative risk , obstetrics , breast cancer , confidence interval , gynecology , case control study , family planning , birth control , cancer , population , research methodology , environmental health
In a case‐control study of 141 cases of breast cancer and 279 control patients from the Royal Prince Alfred and Westmead Hospitals during 1980‐1982, we found similar risk factors to those reported for other populations. There was no statistically significant evidence of an increased risk of cancer from the use of oral contraceptive agents; the crude estimate of relative risk for patients who had used oral contraceptive agents at some time was 1.3 with 95% confidence limits of 0.8 and 1.9. After adjustment for other risk factors (age at first live birth, age at menarche, number of pregnancies, menopausal status, bilateral oophorectomy and years of education), the estimate of the relative risk of ever having used an oral contraceptive agent was 0.9 with 95% confidence limits of 0.6 and 1.5. Further analysis in terms of duration of use and dosage also provided no evidence of an increased risk.