Age-standardised baseline characteristics of Nurses’ Health Study (NHS) (N=109 896) and Nurses’ Health Study II (NHS II) participants (N=108 727) by Body Mass Index (BMI) categories
| NHS | NHS II | |||||
|---|---|---|---|---|---|---|
| 18.5 ≤BMI <25.0 | 25.0 ≤BMI <30.0 | BMI ≥30.0 | 18.5 ≤BMI <25.0 | 25.0 ≤BMI <30.0 | BMI ≥30.0 | |
| Number of participants | 78 215 (71.2%) | 22 515 (20.5%) | 9166 (8.3%) | 74 944 (68.9%) | 20 970 (19.3%) | 12 813 (11.8%) |
| Age in years, mean (SD) | 43.0 (7.2) | 43.1 (7.1) | 43.1 (7.1) | 34.2 (4.7) | 34.7 (4.5) | 35.0 (4.4) |
| Census tract median family income $ (×1000), mean (SD)* | 66.0 (26.7) | 61.0 (23.2) | 57.7 (21.5) | 61.8 (23.1) | 57.5 (20.4) | 54.1 (18.3) |
| Pack-year smoking (packyr),% | ||||||
| Never | 43.4 | 48.2 | 52.0 | 65.5 | 64.6 | 65.7 |
| <20 | 33.4 | 30.1 | 29.3 | 29.6 | 29.0 | 27.1 |
| 20+ | 23.2 | 21.7 | 18.8 | 4.9 | 6.4 | 7.2 |
| Alcohol use (g/day), % | ||||||
| <5.0 | 61.4 | 73.3 | 84.1 | 77.3 | 83.5 | 89.4 |
| 5.0–14.9 | 24.8 | 18.1 | 11.1 | 19.4 | 13.9 | 8.7 |
| 15.0+ | 13.9 | 8.6 | 4.8 | 3.3 | 2.6 | 1.9 |
| Physical activity (total METs), mean (SD) | 15.1 (21.9) | 12.2 (19.6) | 9.8 (15.5) | 26.9 (38.6) | 21.4 (31.3) | 17.5 (28.2) |
| Menarche before age 12 years, % | 20.6 | 28.4 | 35.8 | 20.9 | 30.8 | 38.8 |
| Oral contraceptive use, % | 48.5 | 43.8 | 42.7 | 84.2 | 83.2 | 80.3 |
| Parous, % | 91.7 | 91.8 | 91.0 | 69.4 | 73.5 | 68.1 |
| Breastfeeding ≥12 months % | 17.5 | 17.0 | 16.6 | 25.7 | 23.5 | 18.8 |
| Postmenopausal (PM), % | 31.4 | 32.1 | 31.8 | 2.1 | 2.6 | 3.7 |
| Current hormone use in PM % | 27.2 | 22.8 | 18.0 | 86.4 | 83.2 | 76.6 |
*Median census tract family income was measured in 1986 for NHS and 1989 for NHSII. The values were based on the 2000 census data and adjusted by Consumer Price Index.
MET, metabolic equivalent.