Maternal breast cancer risk in relation to birthweight and gestation of her offspring

Breast Cancer Research

Table 1 Characteristics of analytic cohort

Characteristic	n	%
Year of birth
1908–39	5899	7.1
1940–49	20,519	24.6
1950–59	21,619	25.9
1960–69	19,350	23.2
1970–96	16,064	19.2
Year of start of analytic follow-up^a
2003–5	24,015	28.8
2006–7	39,062	46.8
2008–13	20,374	24.4
Age at start of analytic follow-up (years)^a
16–34	11,950	14.3
35–44	19,741	23.7
45–54	21,016	25.2
55–64	22,461	26.9
≥ 65	8283	9.9
Parity at start of analytic follow-up^a
1	19,917	23.9
2	42,862	51.4
3	16,229	19.5
≥ 4	4443	5.3
Total	83,451	100.0

^aOriginal recruitment (entry) to the cohort for most subjects (n = 76,436), but date of first delivery at ≥ 26 weeks gestation for those who were nulliparous at original cohort entry (n = 7015)

ISSN: 1465-542X