Risk factors for breast fibroadenoma in young women.

In a case-control study, 178 women diagnosed with fibroadenoma (FA) between 1976 and 1982 were compared with 178 age-matched controls in order to assess the risk factors for FA. Women who had a previous diagnosis of breast disease were excluded. The odds ratios (OR) of FA were calculated for different risk factors of breast disease from bivariate analysis as well as multivariate regression analysis. The highest ORs were found for a previous premenstrual mastalgia before first childbirth and a familial history (FH) of breast cancer (BC). Oral contraceptive (OC) use before a first full-term pregnancy (FFTP) does not modify this risk. Also current use of standard oral contraceptives (SOC) containing 50 micrograms of ethinyl estradiol per pill appeared to be protective and the correlation with FA was negative. These findings underline: (a) the predictive value of premenstrual mastalgia for the subsequent development of breast disease; (b) only current high-dose OC use is protective.