Cause
During childhood and teen years, new bone grows faster than
existing bone is absorbed by the body. After age 30, this process begins to
reverse. As a natural part of aging, bone dissolves and is absorbed faster than
new bone is made, and bones become thinner. You are more likely to have
osteoporosis if you did not reach your ideal bone
thickness (bone mineral density) during your childhood and
teenage years.
In women, bone loss increases around menopause, when ovaries
decrease production of
estrogen, a hormone that protects against bone loss.
Likewise,
testosterone protects men from bone loss. Osteoporosis
is typically seen in men older than 65, when production of this hormone
declines. In both men and women, the older you get the more likely you are to
have osteoporosis. See an illustration of
healthy
bone versus bone weakened by osteoporosis
.
Not getting enough
calcium,
vitamin D, and
phosphorus contributes to bone thinning. In addition,
a tendency for lower bone mass may pass from parent to child.