: There is a decline in serum 25 hydroxyvitamin D (25OHD), 1,25 dihydroxyvitamin D (1,25(
OH)2D), and
calcium absorption with advancing age, which may lead to
secondary hyperparathyroidism and bone loss. Studies show a relationship between serum 25OHD and bone density in older men and women, with an inverse correlation between bone density and
parathyroid hormone (PTH).
Vitamin D supplementation in this age group improves
calcium absorption, suppresses PTH, and decreases bone loss.
Vitamin D many also reduce the incidence of hip and other nonvertebral fractures, particularly in the frail elderly who are likely to have
vitamin D deficiency. Patients with established vertebral
osteoporosis have lower
calcium absorption than age-matched control subjects, possibly due to reduced serum 1,25(
OH)2D or to relative resistance to the action of
vitamin D on the bowel. Malabsorption of
calcium in women with vertebral
crush fractures does not usually respond to treatment with physiological doses of
vitamin D, but can be corrected by pharmacological doses of
vitamin D or by low doses of
calcitriol or
alfacalcidol. In a recent randomized, controlled study in 46 elderly women with radiological evidence of vertebral
osteoporosis,
alfacalcidol 0.25 micro;g twice daily improved
calcium absorption, decreased serum PTH, and reduced
alkaline phosphatase, whereas
vitamin D2 500-1000 IU daily had no effect over the 6-month study period. Studies of the effect of the
vitamin D metabolites in the management of elderly women with established vertebral
osteoporosis have yielded conflicting results, but suggest that
alfacalcidol and
calcitriol may decrease spinal bone loss and reduce the incidence of vertebral fractures. Although
vitamin D supplementation decreases bone loss and fracture risk in the frail elderly,
vitamin D metabolites may prove more useful in the treatment of elderly women with vertebral
osteoporosis.