PARATHYROID-HORMONE, 25-HYDROXYVITAMIN-D AND 1,25-DIHYDROXYVITAMIN-D CONCENTRATION IN ELDERLY PATIENTS

In 50 patients of a geriatric hospital (33 women, aged 65-96 years, mean age 80 years, and 17 men, aged 68-91, mean age 78.3 years) calcium, albumin, phosphate, urea, creatinine, parathyroid hormone, 25-hydroxyvitamin D, and 1,25-dihydroxyvitamin D were determined. Forty patients with serum creatinine levels up to 1.4 mg/dl (124 Μmol/l) and 10 patients with creatinine concentrations ≥1.5 mg/dl (132Μmol/l) were evaluated. In patients with normal creatinine, a positive correlation was found between parathyroid hormone and age (r=0.41;P<0.01). In patients with elevated creatinine, negative correlations were found in 1,25-dihydroxyvitamin D and calcium (r=-0.724;P<0.05), 1,25dihydroxyvitamin D and creatinine (r=-0.79;P<0.01) and 1,25-dihydroxyvitamin D and phosphate (r=-0.87;P< 0.002). The best correlation was observed in patients with elevated serum creatinine for 1,25-dihydroxyvitamin D and phosphate (r=-0.91;P< 0.001). The results suggest that low levels of calcium and phosphate stimulate the 1-hydroxylation of 25-hydroxyvitamin D even in advanced age and that the calcium metabolism of these patients is frequently disturbed. Nineteen patients had low levels of 25-hydroxyvitamin D, indicating an insufficient supply of vitamin D or rare exposure to sunlight. In 49 of 50 patients, one ore more of the parameters of calcium metabolism were outside the normal range. © 1990 Springer-Verlag.