Menopause
is characterized by the loss of estrogen production by the ovaries. This may occur by
natural means or by the surgical removal of both ovaries. This loss of estrogens
accelerates bone loss for a period ranging from 5 to 8 years. In terms of bone remodeling
(explained in detail on a previous page) the lack of estrogen enhances the ability of
osteoclasts to absorb bone. Since the osteoblasts (the cells which produce bone) are not
encouraged to lay down more bone, the osteoclasts win and more bone is lost than is
produced.
It is well established that
estrogen replacement during menopause protects bone mass and helps protect against the
risk of osteoporotic fractures. The accelerated bone loss during menopause has little
relationship to the amount of calcium intake. After age 60, however, the proper attention
to calcium intake is very important and has been shown to increase bone density. An
important study published in 1992 showed that elderly women who took supplemental dietary
calcium (with vitamin D) had a 30% less fractures (including hip fractures) than similar
women who did not take supplemental calcium. When these investigators looked at these
women again 3 years later, they still had a significantly less rate of fractures, and,
they had a 15 % decreased chance of death. Most endocrinologists feel that the use of
calcium supplements are safe (and inexpensive) and recommend it to most (all?) elderly men
and women unless specific contraindications exist.
The role of androgens (testosterone) in
males is less well understood, but the loss of testosterone will increase the rate of
osteoporosis in men.