The relationship between serum 25-hydroxy-vitamin D levels and other variables related to calcium and phosphorus metabolism in the elderly

Abstract

Abstract. Three groups of elderly people (65–80 years) were studied with regard to their vitamin D status: group 1 (Gl), long-stay geriatric patients; group 2 (G2), residents of an old people's home; group 3 (G3), elderly people living in their own homes. Young adults (35–50 years) served as controls (C). The 25-OH-D was significantly lower in G1 (17 ± 7 nmol/l) than in G2 (38 ± 14), G3 (64 ± 23) and C (70 ± 21), (mean ± sd). The concentration in G2 was significantly lower than in G3 and C. The corrected s-Ca concentration was significantly lower in G1 (2.30 ± 0.17 mmol/l) than in any of the other groups (G2: 2.47 ± 0.11; G3: 2.44 ± 0.10; C: 2.39 ± 0.09 mmol/l). The s-ALP activity was significantly higher in all groups of elderly people (G1: 155 ± 43 U/1; G2: 161 ± 61; G3: 143 ± 41) than in C (104 ± 22). The s-Pi concentration was significantly lower in C (1.16 ± 0.14 mmol/l) than in the elderly (G1: 1.43 ± 0.37; G2: 1.30 ± 0.19; G3: 1.28 ± 0.13). The PTH concentrations in some of G1 (0.68 ± 1.14 μg/l) and G2 (0.47 ± 0.41) were higher than in some of G3 (0.30 ± 0.05) and C (0.23 ± 0.07); the difference was not significant. There was a significant negative correlation between the inverse of the 25-OH-D and the s-Ca and the 25-OH-D and s-ALP. In conclusion, the low 25-OH-D, the low s-Ca and the high s-ALP indicate that a fair number of the long-stay geriatric patients and the residents at the old peoples' home suffer from subclinical osteomalacia.