Characteristics of cases and controls by cohort participation
1974 | 1989 | |||||
---|---|---|---|---|---|---|
% cases (N = 235) | % controls (N = 235) | % cases (N = 105) | % controls (N = 105) | |||
Age at donation | ||||||
≤40 | 20.9 | 20.4 | 3.8 | 2.9 | ||
41–50 | 23.8 | 26.0 | 21.0 | 22.9 | ||
51–60 | 33.6 | 31.9 | 18.1 | 15.2 | ||
≥61 | 21.7 | 21.7 | 57.1 | 59.1 | ||
Education | ||||||
<12 years | 38.3 | 43.0 | 24.8 | 31.4 | ||
≥12 years | 61.7 | 57.0 | 75.2 | 68.6 | ||
Family history of breast cancer | ||||||
(define: mother, sister, grandmother) | ||||||
No | 79.2 | 91.1 | 73.3 | 87.6 | ||
Yes | 20.9 | 8.9 | 26.7 | 12.4 | ||
Age at first birth | ||||||
<20 | 18.7 | 19.2 | 22.9 | 22.9 | ||
20–29 | 40.4 | 35.7 | 51.4 | 49.5 | ||
≥30 | 6.8 | 4.3 | 1.0 | 3.8 | ||
Nulliparous | 11.9 | 10.2 | 13.3 | 9.5 | ||
Missing | 22.1 | 30.6 | 11.4 | 14.3 | ||
Age at menarche | ||||||
<12 | 13.2 | 14.5 | 19.1 | 14.3 | ||
12–13 | 40.4 | 31.9 | 54.3 | 49.5 | ||
≥14 | 17.5 | 17.9 | 16.2 | 22.9 | ||
Missing | 28.9 | 35.7 | 10.5 | 13.3 | ||
Lactation (months) | ||||||
None | 51.9 | 40.0 | 61.9 | 47.6 | ||
1–12 | 16.6 | 14.9 | 19.1 | 20.0 | ||
>12 | 6.0 | 9.8 | 5.7 | 17.1 | ||
Missing | 25.5 | 35.3 | 13.3 | 15.2 | ||
Hormone replacement therapy | ||||||
Never | 58.3 | 48.5 | 65.7 | 54.3 | ||
Ever | 16.6 | 14.9 | 20.0 | 24.8 | ||
Missing | 25.1 | 36.6 | 14.3 | 21.0 | ||
Alcohol consumption | ||||||
(no. of drinks/week) | ||||||
Never | 48.1 | 46.8 | 47.6 | 50.5 | ||
<1 | 12.8 | 8.1 | 17.1 | 12.4 | ||
1–3 | 7.7 | 8.1 | 14.3 | 15.2 | ||
≥4 | 13.2 | 7.2 | 14.3 | 7.6 | ||
Missing | 18.3 | 29.8 | 6.7 | 14.3 | ||
Cigarette smoking (at donation) | ||||||
Never | 60.0 | 57.5 | 64.8 | 63.8 | ||
Former | 16.6 | 15.7 | 23.8 | 21.0 | ||
Current | 23.4 | 26.8 | 11.4 | 15.2 | ||
Time to diagnosis | ||||||
<2 | 48.6 | |||||
3–5 years | 12.3 | NA a | 51.4 | NA | ||
6–10 | 17.9 | |||||
11–15 | 28.5 | |||||
≥16 | 41.3 | |||||
Estrogen receptor status | ||||||
ER-negative | 11.5 | NA | 19.0 | NA | ||
ER-positive | 33.2 | 66.7 | ||||
Unknown | 55.3 | 14.3 |
a NA, not applicable; ER, estrogen receptor.