title: Breast cancer in young women and use of oral contraceptives: possible modifying effect of formulation and age at use.
abstract: A case-control study of 314 breast cancer patients aged less than 37 at diagnosis and 314 individually matched controls was done to assess the influence of oral-contraceptive (OC) use on the risk of the disease. Long-term use before age 25 of combination-type OCs with a "high" content of the progestogen component was associated with increased risk of breast cancer: the relative risk was approximately 4 after 5 years of such use, and 9 cases and no controls had used such combination-type OCs for more than 6 years before age 25. Use of combination-type OCs with a "low" progestogen component appears to increase breast-cancer risk little or not at all.
mesh_terms: D000328:Adult; D000367:Age Factors; D001940:Breast / Q000378:metabolism; D001943:Breast Neoplasms / Q000139:chemically induced*; D003276:Contraceptives, Oral / Q000008:administration & dosage / Q000009:adverse effects*; D004338:Drug Combinations; D004717:Endometrium / Q000378:metabolism; D005260:Female; D006801:Humans; D008938:Mitosis; D009640:Norethindrone / Q000009:adverse effects / Q000031:analogs & derivatives; D000077563:Norethindrone Acetate; D010053:Ovary / Q000378:metabolism; D011247:Pregnancy; D012306:Risk; D013997:Time Factors
chemical_list: D003276:Contraceptives, Oral; D004338:Drug Combinations; D000077563:Norethindrone Acetate; D009640:Norethindrone