OR (95% CI) of breast cancer in pre-menopausal women according to the use of hormonal contraceptive treatment.

(*) Adjusted for: age, socioeconomically status (high/medium/low), BMI (kg/m2), familial history of breast cancer in first degree relatives (yes/no), diabetes(yes/no), number of full term pregnancy, age at first full term pregnancy (years), total duration of breast feeding (months) and age at menarche (years).
(**) additional adjusted for European ancestry.
(***) We defined the recent use as the reported use of contraceptive treatment during the year prior to the date of interview.