Table 2.
Urinary calcium as a fraction of calcium intake for each cohort
| Stone Formers | Nonstone Formers | Urinary Ca2+ ≥ Cohort Median | Urinary Ca2+ < Cohort Median | |
|---|---|---|---|---|
| HPFS (n = 1037) | ||||
| urinary Ca2+ (mg/d) | 194a | 156 | 255c | 121 |
| urinary/dietary Ca2+ intake | 27%a | 19% | 36%c | 15% |
| urinary/total Ca2+ intake | 22%a | 16% | 31%c | 13% |
| NHS I (n = 1246) | ||||
| urinary Ca2+ (mg/d) | 188b | 170 | 252c | 116 |
| urinary/dietary Ca2+ intake | 25%b | 21% | 38%c | 16% |
| urinary/total Ca2+ intake | 16%a | 12% | 22%c | 10% |
| NHS II (n = 1085) | ||||
| urinary Ca2+ (mg/d) | 204a | 171 | 262c | 141 |
| urinary/dietary Ca2+ intake | 25%a | 18% | 33%c | 16% |
| urinary/total Ca2+ intake | 18%a | 13% | 22%c | 11% |
Values are medians. Urinary/dietary Ca2+ values are calculated only in participants not taking calcium supplements (HPFS, n = 538; NHS I, n = 386; and NHS II, n = 398).
a
P values <0.01 comparing stone formers to non-stone formers.
b
P values <0.05 comparing stone formers to non-stone formers.
c
P values <0.01 comparing high to low urinary Ca2+.