Table 1.
Baseline characteristics of the study cohorts
| Variable | HPFS, n=42,919 | NHS I, n=60,128 | NHS II, n=90,629 |
|---|---|---|---|
| Age, yr | 54.3 (9.8) | 52.9 (7.1) | 36.6 (4.6) |
| BMI, kg/m2 | 25.5 (3.4) | 25.2 (4.7) | 24.6 (5.3) |
| History of diabetes, % | 3 | 3 | 1 |
| History of hypertension, % | 21 | 24 | 6 |
| Thiazide use, % | 9 | 14 | 2 |
| Calcium supplements use, % | 23 | 57 | 34 |
| Dietary calcium, mg/d | 802 (306) | 720 (253) | 886 (305) |
| Supplemental calcium, mg/d | 98 (262) | 357 (429) | 129 (273) |
| Magnesium, mg/d | 355 (83) | 300 (69) | 316 (75) |
| Fructose, g/d | 25.3 (11.4) | 21.6 (9.0) | 22.9 (11.0) |
| Oxalate, mg/d | 144 (136) | 119 (92) | 135 (115) |
| Phytate, mg/d | 943 (392) | 708 (269) | 783 (240) |
| Alcohol intake, g/d | 11.5 (15.6) | 6.2 (10.7) | 3.1 (6.1) |
| Fluid intake, L/d | 1.9 (0.8) | 2.0 (0.7) | 2.1 (0.8) |
| Dairy protein, g/d | 15.9 (9.2) | 15.0 (7.8) | 18.6 (9.1) |
| Nondairy animal protein, g/d | 51.5 (18.2) | 47.1 (14.5) | 49.1 (16.2) |
| Vegetable protein, g/d | 24.8 (6.2) | 20.2 (4.2) | 22.5 (5.0) |
| Dietary potassium, mg/d | 3389 (659) | 3002 (562) | 2933 (540) |
Data are reported as means (SD) for continuous variables. HPFS, Health Professionals Follow-Up Study; NHS I, Nurses’ Health Study I; NHS II, Nurses’ Health Study II; BMI, body mass index.