Table 1. Descriptive characteristics of the ABCFR cohort of 4176 women unaffected with breast cancer at baseline.

	Unaffected after 10 years	Censored	Breast cancer within 10 years	Total
Overall	3452	609	115	4176
Age group
20–29	621	19	2	642
30–39	856	27	16	899
40–49	755	44	27	826
50–59	663	55	31	749
60–69	516	86	32	634
70–79	41	378	7	426
Relationship to the index case–control
Sister	1261	81	45	1387
Mother	347	179	22	548
Aunt	435	274	22	731
Other	1409	75	26	1510
Number of relatives with reported breast cancer
0 First degree	1403	283	34	1720
1 First and 0 second degree	1186	162	35	1383
1 First and 1+ second degree	554	89	24	667
2+ First degree	309	75	22	406
Study type
Families of index cases	2133	486	85	2704
Families of index controls/Ashkenazis/twins	1319	123	30	1472

Abbreviation: ABCFR=Australian Breast Cancer Family Registry.