Vitamin D metabolism in the elderly. Evidence of appropriate synthesis of 1,25 (OH) 2 D3
Quesada Gómez, J.; Alonso, J.; Jans, I.; Bouillon, R.
Revista Clinica Espanola 185(9): 436-439
1989
ISSN/ISBN: 0014-2565 PMID: 2623276 Document Number: 345758
Serum levels of 25 OH D3, 1.25 (OH)2 D3, PTH and several other parameters of mineral metabolism were measured in 55 elderly (greater than or equal to 70 years old), at the beginning of fall in Puertollano (38 degrees of latitude), distributed in three groups: healthy elderly who either live at home (Group 1, 16 cases) or in a Social Security Residence (Group 2, 20 cases) and chronically sick or hospitalized elderly patients (Group 3, 19 cases). Every subject had a creatinine serum level less than 1.2 mg/dl. Serum levels of 25 OH D3, in Group 1 were similar to the young control group 24 +/- 10 micrograms/L, while its levels in Groups 2 and 3 were decreased (13 +/- 4 micrograms/L p less than 0.001 and 10 +/- 5 micrograms/L p less than 0.001--respectively). The opposite was founded for PTH. Serum levels of 1.25 (OH)2 D3 were normal when compared to control group in Groups 1 and 2 (49 +/- 8 micrograms/L and 49 +/- 6 micrograms/L) but they were significantly decreased in Group 3: 38 +/- 12 (p less than 0.001). Our results demonstrate that elderly people with enough sun exposure may have adequate 25 OHD3 levels while those who have a restricted exposure will have decreased levels. In the elderly, 1.25 (OH)2 D3 levels are normal if 250 HD3 levels are also normal or sufficient, only very low levels of 250 HD3 are not able to maintain normal serum levels despite their secondary hyperparathyroidism.