Mini MCAT passage: Osteoporosis and treatment options

Osteoporosis is a skeletal disease in which the bones become brittle and fragile from loss of mineral density. In elderly individuals, the risk of osteoporosis increases with age, as peak bone mass is reached by the age of 40 and then steadily declines by about 0.5-1% per year. For postmenopausal women, this rate increases to 2-3% for approximately 8-10 years after menopause before reverting back to the previous rate. Thus, postmenopausal women are at a significantly increased risk of suffering from osteoporosis and pathologic fractures.

Age-related changes in parathyroid hormone and calcitonin, as well as the production of active vitamin D by the kidneys, all contribute to the decline in bone mass. The increased rate of bone loss in post-menopausal women is partly attributed to a deficiency in estrogen, though the exact mechanism remains unknown.

Dietary calcium supplements, vitamin D, and exercise are common first line approaches to dealing with bone loss, but bisphosphonates and estrogen receptor modulators are other options for postmenopausal women suffering from osteoporosis. Patients with severe osteoporosis and an intolerance of bisphosphonates may be candidates for parathyroid hormone therapy. Calcitonin therapy is less preferred because of its relatively modest effect on bone mineral density and fracture prevention.