Table 1. Baseline characteristics of the study population by outcome.
| Factor | Incident renal cell cancer cases (n=172) | Non-cases (n=89 617) |
|---|---|---|
| Mean age at baseline (years) | 50.7 (5.6) | 48.5 (5.6) |
| Mean BMI (kg m−2)a | 26.1 (5.1) | 25.1 (4.7) |
| Mean age at menarche (years) | 13.0 (1.4) | 12.8 (2.2) |
| Mean age at first live birth (years)b | 23.7 (3.7) | 24.2 (4.8) |
| Parity (%) | ||
| Nulliparous | 9.3 | 14.4 |
| 1–2 | 32.0 | 35.5 |
| 3–4 | 40.1 | 38.4 |
| 5+ | 18.6 | 11.7 |
| Postmenopausal (%) | 44.2 | 37.0 |
| Cigarette smoking (%) | ||
| Never smoked | 44.8 | 52.2 |
| Former smoker | 25.0 | 26.0 |
| Current smoker | 30.2 | 21.8 |
| HRT use (% ever)c | 46.1 | 47.0 |
| Oral contraceptives use (% ever) | 51.7 | 58.1 |
a
BMI=body mass index.
b
Among parous women only.
c
HRT=hormone replacement therapy; results among postmenopausal women only.