Late effects: Bone heath & osteoporosis

Osteoporosis: A silent disease

Osteoporosis (or osteopenia) 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 wrists, hips and leg bones. The vertebrae of the spine often collapse, leading to loss of height, spinal curvature, and chronic pain.

How is osteoporosis diagnosed?

Although osteoporosis may be suspected based on a person'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 to perform.

People who have osteoporosis should discuss treatment options with their doctor. Medications, such as calcium and vitamin D supplements and bisphosphonates may be appropriate for the treatment of low bone density. In addition, if you have low levels of male or female hormones, you may also benefit from hormone replacement therapy.

What are the risk factors for osteoporosis?

Characteristics

Osteoporosis is more common in people with the following characteristics:

• Female (especially after menopause)
• Family history of osteoporosis
• Caucasian or Asian race
• Small, thin frame
• Older age

Lifestyle

The following factors may also increase the risk of osteoporosis:

• Cigarette smoking
• Inadequate amounts of dietary calcium
• Low vitamin D levels
• Lack of physical activity
• Too much caffeine (more than three cups of tea, coffee or equivalent daily)
• Too much alcohol (more than two standard drinks per day)

Cancer treatment

The following cancer treatment factors may also increase the risk of osteoporosis:

• A history of treatment with:
  • Corticosteroids (such as prednisone and dexamethasone)
  • Methotrexate
  • Radiation to weight-bearing bones (legs, hips, spine)
• Conditions resulting from prior treatment, including:
  • Low levels of female or male hormones
  • High levels of thyroid hormone
  • Chronic graft-versus-host disease requiring prolonged therapy with corticosteroids
  • Prolonged periods of inactivity (bed rest)
• Other medical treatments, including:
  • Certain anticonvulsants (phenytoin and barbiturates)
  • Aluminium-containing antacids
  • High doses of heparin (used to prevent blood clots), especially with prolonged use
  • Cholestyramine (used to control blood cholesterol)

Many of the medications on this list are essential treatments for certain medical conditions. If you are taking any of these medications, do not change your dosage or stop taking your medication without consulting with your doctor.

What can I do to reduce the risk of osteoporosis?

Fortunately, there are many things you can do to reduce the risk of osteoporosis.

• Regular weight-bearing exercise (such as brisk walking, dancing, tennis and jogging) is ideal to develop and maintain healthy bones. Bicycling and swimming are excellent exercises for general fitness, but as these are not weight-bearing exercises, they may be less effective in building strong bones. If you have problems with your heart, or have painful bones or joints, be sure to check with your doctor 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, yoghurt) and leafy green vegetables. Talking with a dietician may help you design a healthy diet. Over-the-counter calcium supplements also may be useful. If you are lactose intolerant, you may drink a calcium-rich soy milk or lactase treated cows milk.
• Vitamin D is needed in order to absorb calcium. The skin makes this vitamin naturally when exposed to sunlight. Many dairy products also contain vitamin D. In general, you should 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 your doctor before taking any vitamin D supplements.
• Avoid smoking
• Limit alcohol and caffeine intake

What screening is recommended?

After reviewing your treatment history and risk factors, your doctor can advise you regarding the need for bone density testing. Follow up scans may be needed for ongoing monitoring of bone density in some patients.