Ambulatory

Question:

You are CORRECT!!

Bone is a dynamic tissue that is constantly undergoing remodeling throughout life. At anyone time both constructive and destructive processes are occurring at a cellular level. This leads to a net loss of bone that begins in the 30s and 40s and continues throughout a person's life.

During the first 10 years after the loss of ovarian function there is a 10 fold increase in bone loss which results in a 10 fold increase in distal forearm fractures. Numerous studies have demonstrated that the use of postmenopausal estrogen therapy significantly decreases the incidence of osteoporosis in a dose dependent fashion. (176)

The mechanism of action is through estrogen receptors, which are present in bone throughout life. Estrogen's presence stimulates osteoblast activity thereby facilitating the remodeling of bone. This leads to an increase in the deposition of collagen and encourages the formation of new bone. (177)

References:

176. Gynecology ACoOa: Hormone Replacement Therapy. ACOG Technical Bulletin 1992; 167.

177. Eriksen EF CD, Berg NJ, Graham ML, Mann KG, Spelsberg TC, et al: Evidence of estrogen receptors in normal human osteoblast-like cells. Science 1988; 241: 81-86.

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