title: Physiology of bone loss.
abstract: The physiology of bone loss in aging women and men is largely explained by the effects of gonadal sex steroid deficiency on the skeleton. In women, estrogen deficiency is the main cause of early rapid postmenopausal bone loss, whereas hyperparathyroidism and vitamin D deficiency are thought to explain age-related bone loss later in life. Surprisingly, estrogen deficiency also plays a dominant role in the physiology of bone loss in aging men. Many other factors contribute to bone loss in aging women and men, including defective bone formation by aging osteoblasts, impairment of the growth hormone/insulin-like growth factor axis, reduced peak bone mass, age-associated sarcopenia, leptin secreted by adipocytes, serotonin secreted by the intestine, and a long list of sporadic secondary causes. Further elucidation of the relative importance of each of these factors will lead to improved preventive and therapeutic approaches for osteoporosis.
authors.affiliation: Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic College of Medicine, 200 1st Street Southwest, Rochester, MN 55905, USA. Clarke.Bart@Mayo.edu
authors.forename: Bart L
authors.initials: BL
authors.lastname: Clarke
authors.forename: Sundeep
authors.initials: S
authors.lastname: Khosla
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D004967:Estrogens / Q000172:deficiency; D005260:Female; D012739:Gonadal Steroid Hormones / Q000172:deficiency*; D006801:Humans; D006961:Hyperparathyroidism / Q000150:complications*; D008297:Male; D008875:Middle Aged; D010012:Osteogenesis; D010024:Osteoporosis / Q000209:etiology*; D014808:Vitamin D Deficiency / Q000150:complications*; D055815:Young Adult
chemical_list: D004967:Estrogens; D012739:Gonadal Steroid Hormones