Bone health of the elderly is a major global health concern, since about 1 in 3 women and 1 in 5 men suffer from bone loss and fractures, often called
osteoporosis, in old age. Bone health is a complex issue affected by multiple
hormones and minerals. Among all the
hormones involved in bone health,
calcitriol (also
vitamin D), parathyroid, and
sex hormones (especially
estrogen) have been discussed in this review paper. We have discussed the metabolism of these
hormones and their effects on bone health.
Vitamin D can be obtained from diet or formed from
7-dehydrocholesterol found under the skin in the presence of sunlight. The active form,
calcitriol, causes dimerization of
vitamin D receptor and acts on the bones, intestine, and kidney to regulate the level of
calcium in blood. Similarly,
parathyroid hormone is secreted when the serum level of
calcium is low. It helps regulate the level of blood
calcium through
calcitriol.
Sex hormones regulate bone modeling at an early age and remodeling later in life. Loss of ovarian function and a decrement in the level of production of
estrogen are marked by bone loss in elderly women. In the elderly, various changes in the
calcium and
vitamin D metabolism, such as decrease in the production of
vitamin D, decrease in dietary
vitamin D, decreased renal production, increased production of excretory products, decrease in the level of VDR, and decreased
calcium absorption by the intestines, can lead to bone loss. When the elderly are diagnosed with
osteoporosis, medications that directly target bone such as
bisphosphonates,
RANK ligand inhibitors,
estrogen and
estrogen analogues,
estrogen receptor modulators, and
parathyroid hormone receptor agonists are used. Additionally,
calcium and
vitamin D supplements are prescribed.