Osteoporosis

Some bone loss seems to be a normal part of aging, but in some individuals excessive loss can result in a dramatic increase in fractures and deformities of the spine and limbs. It is estimated that as many as 15% of all women in the United States have sufficient bone loss to increase their risk for bone fractures late in life. This is also true for an increasing number of men.

From birth until we are fully-grown, about age 14 in women and 17 in men, our bones increase in size and density. From our teens, until about age 30, our bones continue to become more dense and hold more calcium. A proper diet needs to contain enough calcium to allow bone to achieve their optimal density. This means about 400-800 mg or calcium intake per day, equal to 3 to 6 glasses of milk. The bone we have at age 30 then becomes the "bank" of bone that we use for the rest of our lives.

Beginning at about age 30, we begin to lose bone from the "bank". The more bone we start with, the less likely we are to develop osteoporosis later in life. To some extent this bone loss seems to be a normal part of the aging process. However, the process is increased in individuals who do not take in enough calcium in their diet. In this case, the body increases the rate at which bone is resorbed, or "withdrawn from the bank", in order to have enough calcium in the blood for normal body functions.

This continues in both men and women with an average yearly loss of ? to 1 percent total bone mass in the skeleton. A number of conditions can cause bone loss to occur more rapidly. This significantly increases an individual's risk for developing osteoporosis and fractures at an older age. Lack of dietary calcium, intestinal problems resulting in loss of absorption of calcium or vitamin D, use of low term steroid medications, kidneys problems resulting in calcium loss, and general inactivity can all increase the rate of this loss. Endocrine problems including hyperperithyroidism, Cushing's disease, and hyperthyroidism all cause increased bone loss.

Women are especially prone to osteoporosis. At the time of menopause, when estrogen levels produced by the ovaries drop, women may lose bone at a rate of 4 to 8% of their bone bank per year for several years. Some, or all, of this bone loss can be prevented through the use of estrogen supplements, calcium supplements, exercise, and some other medications. Women going through menopause are encouraged to consider these options, particularly if there is a strong family history of osteoporosis among women in their immediate family. Women who are smaller in stature (i.e. "skinny"), have fair skin or scoliosis, or are from northern European ancestry have increased risk for osteoporosis. Bone mass in many individuals can now be regained using diet and some medications other than estrogens.