Author(s): Peeters PH, Verbeek AL, Krol A, Matthyssen MM, de Waard F
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Abstract Early age at menarche is a known risk factor for breast cancer, some inconsistency in the literature not withstanding. Relative risks for an early menarcheal onset as compared to a late onset vary from 1.0 to 1.9. To avoid (residual) confounding by parity-related factors a case-control study was conducted among nulliparous women. 135 cases and 540 controls were selected from two population-based screening projects for breast cancer in The Netherlands. Four controls were matched to each case for year of birth, for screening-centre, and for number of screening examinations. Women with a menarcheal age of 10 or 11 years showed a 2.2 times (95\% confidence interval: 1.2-4.0) higher risk for breast cancer compared to women who had their first menstrual period at 12 years of age or older.
This article was published in Breast Cancer Res Treat
and referenced in Reproductive System & Sexual Disorders: Current Research