Table 4.

Multivariate-adjusted differences in 24-h urinary oxalate excretion by category of dietary calcium, stratified by kidney stone historya

Dietary calciumDifference in Urinary Oxalate (mg/d)95% CIP for Trendb
Non-stone formers (n = 1168)
    quartile 1Referent
    quartile 2−0.4(−2.0 to 1.2)
    quartile 3−1.0(−2.6 to 0.7)
    quartile 4−0.9(−2.5 to 0.6)
Stone formers (n = 2180)
    quartile 1Referent
    quartile 2−1.9(−3.1 to −0.8)
    quartile 3−2.6(−3.8 to −1.4)
    quartile 4−3.0(−4.2 to −1.8)
  • a Adjusted for age, kidney stone history, cohort, weight (continuous), 24-h urinary excretion of creatinine, potassium, magnesium, and phosphorus (all in quartiles), dietary oxalate (quartiles), supplemental calcium intake (four categories), and total intake of vitamin C (five categories).

  • b P = 0.0005 for interaction between dietary calcium and kidney stone history.