# Table 2 The effect of the various patterns of breast cancer in the family on the age of onset of breast cancer in the women under study (univariate) *

Family characteristics Relative risk at
age 30**
95% C.I.
relative risk at
of age 30
Change of
relative risk per
10 years ***
Overall
Significance
****
≥ 2 cases of female breast cancer in first or second-degree relatives (yes vs. no) 2.20 1.15–4.22 0.851 P = .013
≥ 2 cases of female breast cancer in first-degree relatives (yes vs. no) 4.28 1.89–9.70 0.624 P = .001
≥ 1 case of female breast cancer under age 50 (yes vs. no) 2.82 1.43–5.57 0.800 P = .001
≥ 2 cases of female breast cancer under age 50 (yes vs. no) 5.81 2.16–15.60 0.825 P = .002
≥ 1 case of female breast cancer under age 40 (yes vs. no) 3.21 1.36–7.56 0.825 P = .001
Bilateral breast cancer in affected sister (index patient) (yes vs. no) 4.00 1.55–10.32 0.784 P = .000
Ovarian cancer (yes vs. no) 2.72 0.58–12.83 0.801 P = .294
DCIS in affected sister (index patient) (yes vs. no) 0.89 0.30–2.63 1.184 P = .412
1. * Due to small numbers, results regarding ≥ 2 cases under age 40 and ≥ 1 or 2 case under age 30 of female breast cancer, male breast cancer, breast and ovarian cancer in one person and prostate cancer under age 60 are not presented.
2. ** Due to low prevalence, the hazard ratio can be considered as a relative risk.
3. *** The relative risk at age 30 can be multiplied with this factor for calculating the relative risk at age 40, age 50 and so on.
4. **** Model significance was based on the likelihood ratio of the final model as compared to the O-model without any covariate.