Table 1.

Demographic characteristics and laboratory measurements by quartile of FGF23

VariableQuartile 1 <53.34 RU/ml, n=786Quartile 2 =53.34–70.34 RU/ml, n=785Quartile 3 =70.35–99.33 RU/ml, n=786Quartile 4 >99.33 RU/ml, n=784P Value (for Trend)
Age, yr77±577±578±479±5<0.001
Men, n (%)369 (47%)343 (44%)281 (36%)263 (34%)<0.001
Black race, n (%)181 (23%)121 (15%)98 (13%)107 (14%)<0.001
Smoking status, n (%)0.002
 Never335 (43%)324 (41%)308 (39%)303 (39%)
 Former411 (52%)411 (52%)399 (51%)404 (52%)
 Current40 (5%)50 (6%)79 (10%)77 (10%)
Diabetes, n (%)104 (13%)129 (16%)138 (18%)199 (25%)<0.001
CHF, n (%)23 (3%)44 (6%)57 (7%)156 (20%)<0.001
CHD, n (%)144 (18%)161 (21%)188 (24%)261 (33%)<0.001
BMI, kg/m226.3±4.326.6±4.127.3±4.827.6±5.3<0.001
eGFR, ml/min per 1.73 m280.8±18.174.4±16.769.3±16.258.6±19.4<0.001
ACR, mg/g6.9 [4.3–14.3]8.4 [4.5–17.3]8.3 [4.7–19.0]13.5 [6.1–54.0]<0.001
Albumin, g/dl3.80±0.303.81±0.303.78±0.293.76±0.30<0.01
CRP, mg/L4.08±9.384.19±7.254.97±6.605.64±8.24<0.001
IL-6, pg/ml3.1±2.13.4±2.33.9±2.54.6±2.7<0.001
Calcium, mg/dl9.70±0.539.79±0.589.78±0.559.81±0.640.02
Phosphorus, mg/dl3.70±0.533.72±0.513.79±0.573.95±0.56<0.001
25(OH)D, ng/ml27.8±10.329.0±11.229.4±12.627.6±11.4>0.99
iPTH, pg/ml43.7±18.245.8±21.247.1±21.862.9±51.9<0.001
24,25(OH)2D, ng/ml3.4±1.83.6±1.83.5±1.93.2±1.80.22
VMR0.121±0.0400.124±0.0400.120±0.0420.116±0.0420.08
  • Data are mean±SD, n (%), or median [IQR]. eGFR was calculated by the cystatin C equation. Data are from a subgroup with a random sample of n=881 participants for the following variables: calcium, phosphorus, 25(OH)D, iPTH, 24,25(OH)2D, and VMR. RU, relative unit.