Osteoporosis, which means "porous bones," is a condition of the skeleton in which the amount of calcium present in the bones slowly decreases to the point where the bones become less dense and more prone to fracture. Contrary to popular belief, it is not just a disorder of the elderly woman. It can occur in the college-aged population. People with eating disorders, high performance athletes or patients on certain medications may be at the greatest risk. Even if you have no present high risk factors, building strong bones today may prevent osteoporosis from occurring in the future.
Our skeleton provides structural support for our muscles and organs. In addition, it serves as a storage depot for 99% of the body's calcium. The remaining 1% is free to circulate in the blood and is essential for crucial body functions including muscle contraction, nerve function and blood clotting.
Bone is not a lifeless structure. It is a living, growing tissue. In order to meet our body's needs it is constantly being broken down and reformed again in a process called remodeling. The breakdown is done by cells known as osteoclasts which dig holes into the bone, releasing the small amounts of calcium into the bloodstream that are necessary for other vital functions. Cells called osteoblasts then rebuild the skeleton, first by filling in the holes with collagen and then by laying down crystals of calcium and phosphorus.
From childhood to adulthood, bone is made faster than it is broken down and bones become larger and denser. Peak bone mass occurs by the mid 20's. The remodeling process, in which bone is broken down faster than it is made, begins to reverse as early as age 35 and results in precipitous bone loss after menopause. It is crucial that young adults "bank" enough calcium in their bones to draw on later in life to prevent osteoporosis. A person who has exceptionally dense bones to begin with will probably never lose enough calcium to reach the point where osteoporosis occurs. However, a person who has low bone density could easily develop osteoporosis despite losing only a relatively small amount of calcium.
Many factors affect the remodeling process. A deficiency of the hormone estrogen appears to increase bone loss. This occurs naturally after menopause but can also occur with surgical removal of the ovaries. Intense exercise such as marathon running affects hormonal levels and may lead to osteoporosis. Severe underweight and undernutrition problems that occur in patients with eating disorders can lead to hormonal deficiencies which cause amenorrhea (absence of menstrual periods) and severe osteoporosis.
Early osteoporosis may have no symptoms. Symptoms occurring LATE in the disease include:
- Fractures of the vertebrae, wrists or hips following very minor trauma
- Low back pain
- Neck pain
- Bone pain or tenderness
- Loss of height over time (may be as much as 6 inches)
- Stooped posture
- Being female (80% of osteoporosis occurs in women)
- Increasing age: after 65 about 30% of women have osteoporosis
- Being postmenopausal, either due to natural or surgical menopause (decreased estrogen)
- Estrogen deficiency due to abnormal absence of menstruation. This can occur in persons with eating disorders or high performance athletes. In fact, over half of anorexics have osteoporosis with bones resembling those of women in their 70s or 80s.
- Ethnic heritage - Caucasian and Asian women are at highest risk. Risk is lower for African American and Latino women.
- Thin, slight body frame
- Lifestyles that increase the risk of osteoporosis include smoking, alcohol use, high caffeine use, lack of exercise and low intake of calcium and vitamin D.
- Certain medications may increase risk including steroids, excessive thyroid medications, anticoagulants, antiepileptic drugs and immunosuppressants.
- Certain metabolic diseases can cause secondary osteoporosis.
Men start with higher bone density and lose calcium at a slower rate than women, which is why their risk is lower. However, men can develop osteoporosis. In men, a testosterone deficiency may contribute. Many of the risk factors, such as ethnic heritage, body frame, lifestyle and medication risks listed above, are the same as for women. However, men typically develop osteoporosis at a later age than women (after 60).
Osteoporosis can be confirmed by bone-density testing. This is usually suggested for women over 65, postmenopausal women with risk factors of osteoporosis or who have had a fracture. Young women who have risk factors for osteoporosis such as having an eating disorder or absence of menstruation from over-exercising should also consider being tested.
Currently, the most accurate technique for determining bone density is dual x-ray absorpitometry (DEXA). The measurements are made by detecting the extent to which bones absorb photons that are generated by very low-level x-rays. This test is painless and quick. When the bone mineral density is 2.5 standard deviations below the average for young adults, a diagnosis of osteoporosis is made. If the bone mineral density is between 1 and 2.5 standard deviations below the norm, a patient is diagnosed with osteopoenia, a slightly less advanced form of weakened bones. One standard deviation below the norm in a measurement of hipbone density is equivalent to adding 14 years to a person's age-related risk of fracture.
Treatment cannot eliminate osteoporosis, but medicines may be able to slow down the loss of bone. Most of the medicines available today are primarily aimed at treating osteoporosis in the postmenopausal woman. Studies are presently underway investigating therapies for the younger patient with osteoporosis. Oral contraceptives have not been found to be effective in treating anorexics with osteoporosis. Investigational studies are looking at insulin-like growth factor-1, testosterone, and a postmenopausal osteoporosis medication as possible therapeutic agents for young women.
Increasing calcium intake to 1500 mg per day, increasing vitamin D to 800 IU per day and maintaining normal weight and exercise patterns to restore hormonal balance may be helpful in preventing further bone loss.