Table 3. 

Markers of mineral metabolism among European American and African-American participants in the CRIC study

European AmericanAfrican AmericanaP valuef
Variablesn=1523Overall 
n=1490Quartile 1bn=373Quartile 2cn=368Quartile 3dn=373Quartile 4en=376
Phosphorus (mg/dL)3.60±0.62g3.77±0.673.78±0.653.76±0.723.77±0.693.75±0.610.57
Calcium (mg/dL)9.23±0.479.21±0.529.19±0.529.23±0.529.20±0.549.21±0.500.64
Alkaline phosphatase (U/L)80.7 (79.4, 82.0)g92.1 (90.6, 93.6)90.2 (87.2, 93.3)91.6 (88.5, 94.8)92.6 (89.6, 95.8)94.0 (90.8, 97.2)0.09
FGF23 (RU/ml)149.8 (144.1, 155.7)g164.4 (158.1, 171.0)162.4 (149.7, 176.2)170.9 (157.4, 185.6)165.9 (152.9, 180.0)158.8 (146.4, 172.2)0.60
PTH (pg/ml)46.3 (44.7, 48.0)g68.6 (66.2, 71.0)65.2 (60.5, 70.4)69.9 (64.8, 75.5)70.3 (65.2, 75.8)68.9 (64.0, 74.3)0.32
Urine calciumh (mg/day)52.2 (49.4, 55.2)g28.6 (27.0, 30.3)31.4 (27.8, 35.5)27.1 (24.0, 30.7)26.0 (23.0, 29.3)30.2 (26.7, 34.1)0.56
FECa (%)h0.69 (0.66, 0.73)g0.45 (0.43, 0.48)0.47 (0.42,0.53)0.43 (0.38, 0.48)0.43 (0.38, 0.48)0.48 (0.43, 0.54)0.92
Urine phosphorus (mg/day)h871.6±360.5g664.0±317.5711.4±337.6666.6±314.6634.6±289.3643.7±322.50.002
FEPO4 (%)h31±15g26±1427±1426±1427±1625±130.13
  • Results are presented as arithmetic mean±SD or geometric means (95% confidence intervals). FGF23, fibroblast growth factor 23; PTH, parathyroid hormone; FECa, urine fractional excretion of calcium; FEPO4, urine fractional excretion of phosphorus.

  • a African-American data is shown overall and stratified by quartiles of percentage African ancestry.

  • b Percentage African ancestry <73.6%.

  • c Percentage African ancestry 73.6%–79.6%.

  • d Percentage African ancestry 79.7%–83.8%.

  • e Percentage African ancestry >83.8%.

  • f P for trend across the quartiles of African ancestry among African Americans.

  • g P<0.001 comparing European Americans to African Americans.

  • h Analyses restricted to 2855 participants with plausible 24-hour urine data (1462 European Americans, 1393 African Americans).