During childhood and into young adulthood, bone formation occurs faster than bone loss, causing bones to grow and become heavier andmore dense. As a person ages, the process of bone removal gradually overtakes bone formation, and bones slowly lose strength as part of the normal aging process.
Osteoporosis is a disorder resulting from too little new bone formation or too much bone loss, causing bones to become weak. Most people do not have symptoms, especially in the early stages. As bones become weaker, fractures may occur after minimal trauma, such as a fall. Osteoporosis may occur in any bone, but most commonly affects the wrist, leg, and hip bones.
Although osteoporosis may be suspected based on a patient’s symptoms and risk factors, the diagnosis is made by measuring bone density with special X-ray techniques called DEXA or bone density scans. These scans do not expose patients to large amounts of radiation, and generally take less than 20 minutes. People who have osteoporosis should discuss treatment options with their healthcare provider. Medications such as bisphosphonates and calcitonin are available specifically for the treatment of low bone density. In addition, patients with low levels of male or female hormones, or low levels of growth hormone may also benefit from hormone replacement therapy.
Risk Factors for Children’s Cancer Survivors
- Corticosteroids (such as prednisone and dexamethasone)
- Radiation to weight-bearing bones (legs, hips, spine)
- Low levels of female or male hormones as a result of treatment, such as radiation therapy to the brain, radiation therapy to the testicles or ovaries, surgical removal of the testicles or ovaries, or high doses of alkylating chemotherapy (such as cyclophosphamide, ifosfamide, nitrogen mustard, melphalan, busulfan, BCNU, CCNU, and procarbazine)
- Growth hormone deficiency resulting from treatment, such as radiation therapy to the brain
- High levels of thyroid hormone (hyperthyroidism) resulting from treatments such as radiation therapy to the brain, neck, or chest
- High doses of thyroid hormone
- Certain anticonvulsants (phenytoin and barbiturates)
- Aluminum-containing antacids (such as Maalox® or Amphogel)
- Gonadotropin-releasing hormone agonists such as Lupron (used for treatment of early puberty and endometriosis)
- High doses of heparin (used to prevent blood clots), especially with prolonged use
- Cholestyramine (used to control blood cholesterol)
- Chronic graft-versus-host disease requiring prolonged therapy with corticosteroids (such as prednisone) following stem cell or bone marrow transplant
- Prolonged periods of inactivity (bed rest)
Lowering the Risk of Osteoporosis
Fortunately, there are many ways to help reduce the risk of osteoporosis. Regular weight-bearing exercise (such as brisk walking, dancing, aerobics, and jogging) helps to develop and maintain healthy bones. Bicycling and swimming are excellent exercises for general fitness, but these are NOT weight-bearing exercises, and they do not help to build strong bones. Exercises that are especially good for bone health include higher-impact weight-bearing activities, such as hopping, jogging, and jumping rope. Resistance exercises, such as light weight lifting, also help to build strong bones and are especially important for bones of the upper body, including the arms and shoulders. People with heart problems or painful bones or joints should discuss their individual health status and cancer treatment history with a healthcare provider before starting any new exercise program.
A diet high in calcium also is important in preventing osteoporosis. Most doctors recommend 1000-1500 mg a day, which means a diet rich in dairy products (milk, cheese, yogurt) and leafy green vegetables. A nutritionist can help design a healthy diet. Over-the-counter calcium supplements also may be useful. Vitamin D is needed in order to absorb calcium. Vitamin D is made naturally when the skin is exposed to sunlight. Many dairy products also contain vitamin D. In general, do not take more than 800 units of Vitamin D per day. Taking too much vitamin D may be harmful, so it’s best to check with a healthcare provider before taking any vitamin D supplements.
What Screening is Recommended?
After reviewing an individual’s treatment history and risk factors, a healthcare provider can decide if bone density testing is advisable. For those at risk, a bone density scan is generally done at age 18, but this can be done at an earlier age if needed. The timing of the test is based on evaluation of each individual patient. Follow-up scans may be needed for ongoing monitoring of bone density in some patients.