June 22, 2013
Bone is a living, growing material. It has a framework of protein. Calcium strengthens the bone framework. The outer layer of bone has nerves and a network of small blood vessels.
Old bone is removed and new bone is added all the time. In children and young adults, more bone is added than is removed. Our bones get larger, heavier and stronger. After age 30, more bone is removed than is added. Bones become lighter and more brittle.
People with HIV have unusually high rates of low bone mineral density and broken bones. This may be because of HIV infection itself. It may be made worse by some medications used to treat HIV.
Osteoporosis, or porous bone, occurs when too much mineral is removed from the bone framework. The bones become brittle and break (fracture) more easily. The most common fractures are in the hip, the spine (vertebrae) and the wrist. Osteopenia is a mild or moderate loss of bone minerals.
Loss of bone mineral density can occur without any pain or symptoms. Often, the first sign of osteoporosis is a bone fracture in the hip, wrist, or spine.
As we age, our bones lose their mineral content. There are many factors that increase your risk for osteoporosis. Some you can control; others you can't.
Factors you cannot control include:
Factors that you can control include:
Some health conditions also increase the risk of osteoporosis:
HIV infection causes a loss of bone mineral density. It is not clear how this happens. Studies suggest that HIV itself, chronic inflammation, other medical conditions or certain medications may contribute to bone disease.
Long-term use of the antacids known as proton pump inhibitors can reduce bone mineral density. Common brands include Prevacid, Prilosec, and Nexium.
On the other hand, you might increase your calcium levels if you use calcium carbonate antacids such as Tums and Rolaids.
Unfortunately, there may be no signs of osteoporosis until you break a bone. The only way to tell how fast your bones are losing mineral content is through tests. A DEXA scan, or Dual Energy X-ray Absorptiometry, is the most common test to measure bone mineral density. DEXA scans are quick, painless scans. DEXA scans are recommended for HIV+ people 50 years of age or older.
Bone mineral density is reported as grams per square centimeter. This is compared to the maximum bone mineral density for a healthy 30-year-old of the same sex. T-score measures how far your bone mineral content is below the peak value. Osteoporosis is defined as a T-score of
Bone density results can also be reported as a Z-score. This compares your bone mineral content to people of your same age and sex.
To prevent osteoporosis, get plenty of calcium while you are building bone (up to age 30). The higher your peak bone density, the better.
If you have osteopenia or osteoporosis, you can reduce your risk of fractures:
Several studies showed that alendronate (Fosamax) increases bone mineral density in HIV+ individuals. Fosamax is a bisphosphonate medication. Some drugs of this type can be taken just once a month or once a year. The FDA has noted bone problems in the jaw and thigh as possible long term side effects of these drugs. Review with your doctor how long you should continue bisphosphonate therapy.