Table 1.

Morning fasting blood and 24-h urine composition in healthy elderly and young mena

ParameterElderly (n = 9)Young (n = 13)
Age (yr)74 ± 239 ± 1
Body weight (kg)84 ± 278 ± 2
Blood
    creatinine (mg/dl)0.96 ± 0.040.92 ± 0.03
    ionized calcium (mg/dl)4.84 ± 0.044.84 ± 0.03
    total calcium (mg/dl)9.2 ± 0.1b9.5 ± 0.1
    magnesium (mg/dl)2.06 ± 0.032.00 ± 0.04
    phosphorus (mg/dl)2.7 ± 0.1c3.6 ± 0.1
    iPTH (pg/ml)42 ± 4b23 ± 4
    1,25(OH)2D (pg/ml)37 ± 231 ± 2
    25(OH)D (ng/ml)20 ± 222 ± 1
Urine
    calcium (mg/24 h)190 ± 25174 ± 19
    phosphorus (mg/24 h)1071 ± 661144 ± 55
    magnesium (mg/24 h)116 ± 14d166 ± 11
    FEPi (%)28.2 ± 1.4c16.8 ± 1.2
    cAMP (nmol/100 ml GF)2.75 ± 0.18d2.16 ± 0.15
    nephrogenous cAMP     (nmol/100 ml GF)1.83 ± 0.19d1.18 ± 0.16
    creatinine clearance     (ml/min)96 ± 6c132 ± 5
  • a Data are means ± SEM. iPTH, intact parathyroid hormone; FEPi, fractional excretion of phosphate; GF, glomerular filtrate. Reprinted from reference (32), with permission.

  • Elderly versus young men:

  • b P < 0.01,

  • c P < 0.001,

  • d P < 0.05.