The relationship between oral contraceptives (OC) and breast-cancer risk was analysed using data from a case-control study conducted between June 1991 and February 1994 in 6 Italian centres on 1,991 patients below age 65 with histologically confirmed incident breast cancer and 1,899 controls admitted to hospital for a wide range of acute, non-neoplastic, nonhormone-related diseases. « Ever OC use » was reported by 18% of cases versus 14% of controls, corresponding to a multivariate odds ratio (OR) of 1.1 (95% confidence interval, CI 0.9 to 1.4).
The ORs were 1.3 for use lasting<1 year, 1.1 for 1 to 4 years, 0.9 for 5 to 8 years, and 1.2 for over 8 years.
With reference to age at first use, there was some indication that the OR was elevated in women who had started use before age 30, but not in those starting at a later age.
With reference to time since last OC use, the OR was above unity for women who had stopped for less than 10 years (1.6 for 1 to 4 years ; 1.7 for 5 to 9 years), but the OR declined to unity for women who had stopped OC use for 10 years or longer.
The OR for women who had stopped OC use for less than 10 years was consistently elevated across shrata of selected covariates, and was directly related to the duration of use (OR 1.3 for<5 years, 1.7, for =5 years).
Mots-clés Pascal : Tumeur maligne, Glande mammaire, Facteur risque, Epidémiologie, Contraceptif, Voie orale, Italie, Europe, Adulte, Homme, Glande mammaire pathologie, Etude cas témoin
Mots-clés Pascal anglais : Malignant tumor, Mammary gland, Risk factor, Epidemiology, Contraceptive, Oral administration, Italy, Europe, Adult, Human, Mammary gland diseases, Case control study
Notice produite par :
Inist-CNRS - Institut de l'Information Scientifique et Technique
Cote : 95-0166069
Code Inist : 002B20E02. Création : 09/06/1995.