Biochemical effects of calcium and vitamin D supplementation in elderly, institutionalized, vitamin D-deficient patients

Abstract

Forty-five subjects (41 women and 4 men) in long-stay and medium-stay facilities, aged 74 to 95 years (mean 86.4 years), with 25-hydroxy-vitamin D levels less than 12 ng/ml, were treated for six consecutive months with two tablets per day of a preparation containing vitamin D3 (800 IU/day) and calcium carbonate (1 g elemental calcium/day). Serum levels of 25-hydroxy-vitamin D were very low at baseline (5.6 +/- 0.4 ng/ml) and rose significantly under treatment, to normal values, 33.2 +/- 1.2 and 40.9 +/- 2.1 ng/ml after three and six months, respectively (p < 0.001 for both comparisons). Serum calcium increased significantly, by 4.5% (p < 0.001) during the first three months, and remained at a plateau thereafter. Corrected serum calcium rose by 8.9% (p < 0.001) during the trial. No patient developed hypercalcemia. Serum parathyroid hormone levels, which were elevated at baseline (71.6 +/- 5.8 pg/ml; normal, 12 to 54 pg/ml), decreased gradually and significantly throughout the treatment period, by 43.0% and 67.1% after three and six months, respectively (p < 0.001 for both comparisons). Serum alkaline phosphatase activity fell concomitantly, by 9.9% after three months (p < 0.01) and 36.5% after six months (p < 0.001). In conclusion, the preparation used in our study is effective in correcting both the vitamin D deficiency that is prevalent in elderly institutionalized patients and the resultant increase in bone turnover.