Table 1.
Age-standardized characteristics (means [SD] or percentages) according to baseline waist circumference in the Nurses’ Health Study (1986) and Nurses’ Health Study II (1993)
| Characteristics | NHS | NHS2 | ||||
|---|---|---|---|---|---|---|
| Quintile 1 | Quintile 3 | Quintile 5 | Quintile 1 | Quintile 3 | Quintile 5 | |
| (n = 8282) | (n = 9424) | (n = 9517) | (n = 11 527) | (n = 8393) | (n = 9868) | |
| Mean waist circumference (SD), cm | 66.0 (2.6) | 76.7 (1.5) | 96.3 (8.2) | 65.7 (2.7) | 76.7 (1.4) | 98.6 (10.2) |
| Mean hip circumference (SD), cm | 91.9 (5.4) | 99.1 (5.7) | 113.1 (11.1) | 91.4 (5.0) | 98.9 (5.7) | 114.6 (13.3) |
| Mean waist-to-hip ratio (SD) | 0.72 (0.05) | 0.78 (0.05) | 0.86 (0.08) | 0.72 (0.04) | 0.78 (0.04) | 0.87 (0.10) |
| Mean body mass index (SD), kg/m2 | 20.7 (2.0) | 23.6 (2.2) | 30.6 (4.8) | 20.6 (1.9) | 23.5 (2.4) | 31.3 (6.0) |
| Mean height (SD), inches | 63.7 (2.3) | 64.6 (2.4) | 64.9 (2.5) | 64.2 (2.5) | 65.1 (2.6) | 65.3 (2.7) |
| Mean age (SD), ya | 50.9 (7.0) | 53.6 (7.0) | 55.0 (6.8) | 38.1 (4.6) | 38.8 (4.6) | 39.6 (4.6) |
| Mean age at menarche (SD), y | 12.7 (1.5) | 12.6 (1.4) | 12.4 (1.5) | 12.6 (1.5) | 12.5 (1.4) | 12.1 (1.4) |
| Mean parity (SD)b | 2.9 (1.4) | 3.2 (1.5) | 3.3 (1.6) | 2.1 (0.9) | 2.2 (0.9) | 2.2 (1.0) |
| Mean age at first birth (SD), y | 25.1 (3.3) | 25.1 (3.2) | 25.2 (3.4) | 25.9 (4.2) | 26.0 (4.2) | 25.7 (4.4) |
| Mean alcohol intake (SD), g/day | 6.6 (10.5) | 7.0 (11.5) | 5.1 (11.0) | 3.5 (6.1) | 3.4 (6.4) | 2.5 (6.1) |
| Mean physical activity, MET-h/wk | 19.0 (24.6) | 14.7 (20.1) | 10.6 (16.2) | 27.7 (33.5) | 20.6 (24.8) | 16.0 (22.2) |
| Family history of breast cancer, % | 8.1 | 8.5 | 8.3 | 6.2 | 6.2 | 5.9 |
| History of benign breast disease, % | 40.1 | 36.3 | 28.4 | 42.9 | 40.2 | 34.8 |
| Smoking status | ||||||
| Current smoker, % | 24.4 | 20.6 | 18.0 | 11.5 | 10.7 | 11.6 |
| Past smoker, % | 31.6 | 34.3 | 36.6 | 21.7 | 24.1 | 23.3 |
| Postmenopausal, %c | 68.4 | 68.4 | 69.9 | 4.2 | 4.8 | 5.7 |
| Mean age at menopause (SD), yc,d | 48.4 (5.6) | 48.7 (4.8) | 48.7 (4.7) | 39.2 (4.4) | 39.6 (3.9) | 39.5 (3.7) |
| Postmenopausal hormone usee | ||||||
| Current use, % | 34.2 | 31.0 | 20.8 | 52.5 | 53.6 | 49.7 |
| Past use, % | 21.0 | 22.1 | 23.2 | 10.1 | 7.8 | 12.1 |
Value is not age adjusted. MET = metabolic equivalent tasks; NHS = Nurses’ Health Study; NHS2 = Nurses’ Health Study II.
Number of children among parous women.
For NHS, at the last cycle of follow-up (2014–2016), 100.0% were postmenopausal, and age at menopause was 49.6 (4.5), 49.9 (4.4), and 49.7 (4.5) years for the first, third, and fifth quintile, respectively. For NHS2, at the last cycle of follow-up (2015–2017), 97.0%, 97.1%, and 96.9% were postmenopausal, and age at menopause was 49.9 (4.5), 50.2 (4.3), and 49.8 (4.5) years for the first, third, and fifth quintile, respectively.
Natural menopause or menopause due to bilateral oophorectomy.
Postmenopausal hormone use among postmenopausal women only.