When age-specific RRs were considered, the breast cancer RRs for BRCA1 PV carriers were higher before age 40 (RR (95% CI) was 25.1 (9.1–69.3) for age group 20–29 and 27.0 (18.9–38.9) for age group 30–39) and then decreased with increasing age (RRs (95% CIs) were 16.1 (11.4–22.8), 12.1 (7.9–18.5), 6.4 (2.8–14.8) and 10.1 (3.4–30.0) for age groups 40–49, 50–59, 60–69 and 70–79, respectively, p-value for trend = 0.018). This evidence concerns the gene BRCA1 and breast cancer.