VITAMIN-D DEFICIENCY IN ELDERLY NURSING-H OME RESIDENTS OF BUENOS-AIRES

Several studies have shown that vitamin D (Vit. D) deficiency in elder ly people enhances bone mass loss. Most of these studies have been car ried out in areas of low solar irradiation. In order to establish Vit. D circulating levels in elderly people in our community (34 degrees S ) and their relationship with bone metabolism, 34 men and 33 women wer e studied at the end of the summer. These subjects, all residents of n ursing homes, had a mean age of 81.9 + 8.1 years (range 69-99). Calcem ia, parathyroid hormone (PTH and 25-hydroxyvitamin D (25(HO)D) were me asured in serum and bone markers in serum and urine. Bone densitometry (BMD) of cortical and trabecular bone in the forearm (distal third of the radius (R33%) and ultradistal (RUD), respectively) were performed using X-ray absorptiometry. We found: 1) Low serum 25(HO)D (14.4 + 1. 7 ng/ml) at summer's end. 40.5% showed levels < 10 ng/ml. 2) Secondary hyperparathyroidism (PTH: 169.4 + 30.9 pg/ml). 3) Hypocalcemia was ob served in 34.5% of elderly people. 4) Increased bone turnover in the s ubpopulation with hypovitaminosis D. 5) The serum levels of 25(HO)D co rrelated with BMD R33% (r = 0.55, n = 54, P < 0.001), with BMD RUD (r = 0.50, n 54, P < 0.001) and with PTH (r = -0.44, n = 42, P < 0.01). A deficiency of Vit.D was found in our population of elderly people, pr obably due to diminished epidermic production of its precursors and/or to scant exposure to sunlight in the elderly. The decrease is associa ted to age. The positive correlation of 25(HO)D with bone mass (cortic al and trabecular bone) underscores its importance for the preservatio n of bone mass. Hyperparathyroidism, triggered by VitD deficit, enhanc es bone loss.