Table 3.

Multivariate-adjusted differences in 24-h urinary calcium excretiona

Difference Urinary Calcium (mg/d)95% CIP for Trend
Total calcium intake
    quartile 1Referent
    quartile 28(−1 to 16)
    quartile 314(6 to 23)
    quartile 418(10 to 27)
0.01
Dietary calcium intake (non-supplement users)
    quartile 1Referent
    quartile 25(−7 to 17)
    quartile 39(−3 to 22)
    quartile 411(−2 to 24)
0.05
Caffeine intake
    quartile 1Referent
    quartile 20(−8 to 8)
    quartile 35(−3 to 13)
    quartile 410(2 to 18)
0.004
Urinary magnesium
    quartile 1Referent
    quartile 229(21 to 37)
    quartile 343(34 to 51)
    quartile 471(62 to 81)
<0.001
Urinary sodium
    quartile 1Referent
    quartile 215(6 to 23)
    quartile 320(11 to 28)
    quartile 437(27 to 47)
<0.001
Urinary sulfate
    quartile 1Referent
    quartile 211(2 to 20)
    quartile 322(13 to 31)
    quartile 444(33 to 55)
<0.001
Urinary citrate
    quartile 1Referent
    quartile 221(13 to 30)
    quartile 334(25 to 43)
    quartile 461(51 to 70)
<0.001
Urinary phosphorus
    quartile 1Referent
    quartile 26(−3 to 14)
    quartile 319(9 to 28)
    quartile 437(26 to 48)
<0.001
Urinary volume
    quartile 1Referent
    quartile 217(8 to 25)
    quartile 321(12 to 30)
    quartile 424(14 to 33)
<0.001
Urinary potassium
    quartile 1Referent
    quartile 2−20(−11 to −28)
    quartile 3−30(−21 to −40)
    quartile 4−49(−39 to −59)
<0.001
  • a Adjusted for age, kidney stone history, cohort, weight, calcium intake, caffeine intake, thiazide use, history of gout, 24-h urinary excretion of creatinine, and other urinary factors. See Table 1 for median and 25th-75th percentile values for each factor.