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

* 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.

** Due to low prevalence, the hazard ratio can be considered as a relative risk.

*** 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.

**** Model significance was based on the likelihood ratio of the final model as compared to the O-model without any covariate.