Table 1.

Baseline characteristics of the study cohorts

VariableHPFS, n=42,919NHS I, n=60,128NHS II, n=90,629
Age, yr54.3 (9.8)52.9 (7.1)36.6 (4.6)
BMI, kg/m225.5 (3.4)25.2 (4.7)24.6 (5.3)
History of diabetes, %331
History of hypertension, %21246
Thiazide use, %9142
Calcium supplements use, %235734
Dietary calcium, mg/d802 (306)720 (253)886 (305)
Supplemental calcium, mg/d98 (262)357 (429)129 (273)
Magnesium, mg/d355 (83)300 (69)316 (75)
Fructose, g/d25.3 (11.4)21.6 (9.0)22.9 (11.0)
Oxalate, mg/d144 (136)119 (92)135 (115)
Phytate, mg/d943 (392)708 (269)783 (240)
Alcohol intake, g/d11.5 (15.6)6.2 (10.7)3.1 (6.1)
Fluid intake, L/d1.9 (0.8)2.0 (0.7)2.1 (0.8)
Dairy protein, g/d15.9 (9.2)15.0 (7.8)18.6 (9.1)
Nondairy animal protein, g/d51.5 (18.2)47.1 (14.5)49.1 (16.2)
Vegetable protein, g/d24.8 (6.2)20.2 (4.2)22.5 (5.0)
Dietary potassium, mg/d3389 (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.