Several conditions have been reported linked to bone changes.

Even though these symptoms may not be side effects of HIV drugs this is a new area of research that is important to know about.

The two main changes linked to bone are:

1. Changes in content and structure of bone where the bone becomes thinner. This is called oesteopenia at mild levels and osteoporosis at more severe levels and requires treatment;
2. Interruption of proper blood supply to the bone, which causes death of bone tissue - osteonecrosis and avascular necrosis (AVN).

Protease-based combinations have been linked to reduced bone mass – and this was found comparing HIV-positive people on treatment to HIV-positive people not using treatment.

However, other studies have not found this link, and one study found people using nelfinavir maintained stable levels and that people using indinavir may have had improved bone mass changes.

Changes in bone mineral density have been reported in people using combination therapy. It is unclear whether these symptoms are the result of HIV or side effects of the drugs used to treat it.

These changes in bone structure often overlap with issues of lipodystrophy and may be related to those metabolic changes and the way the body processes sugar and fat. In HIV-negative people corticosteroids (like prednisone) and heavy alcohol use are associated with higher risk of bone problems.

Other risk factors for osteoporosis include Caucasian/Asian race, low body weight, cigarette smoking, lack of physical activity, family history of osteoporosis and early menopause.

Your bones are a living structure, 10% of which naturally die each year to be replaced by new cells. If the bone isn’t replaced quickly enough or in sufficient quantities, they can become thinner and more brittle.

Osteopenia and is very common in older people and several studies showed high levels (between 20–40%) in people with lipodystrophy.

Osteoporosis is a more serious progression of osteopenia and can be diagnosed with a DEXA scan. Unlike osteopenia this can lead to fractures and pain (commonly to the spine in men and the hip in women, although this is as yet unknown in HIV).

With osteonecrosis and AVN, inadequate blood supply reaches the bone, and these tissues then die as a result. It is much less common, and usually affects hip, shoulder or knee joints, and requires replacement surgery.

It is very common for corticosteroid use to be a contributing factor in cases of AVN.

Early diagnosis of AVN makes a big difference to the success of treatment as well as your quality of life. If you experience pain in these joints, ask your doctor to refer you to a specialist, and to provide an MRI scan that can make an appropriate diagnosis.

Treatment and prevention measures are similar whether you are HIV-positive or not. Reducing smoking and alcohol, taking exercise and eating a diet adequate in calcium, protein and vitamin D (and spending some time in the sunshine) should protect you against bone mineral loss.

Bone building nutrients include calcium and vitamin D3 (colecalciferol) and any deficiency should be corrected by increasing dietary intake or use of supplements. Recommendations for protecting bones are 500-1000mg daily calcium for adults. The dose of vitamin D3 for osteoporosis is probably 400-800 IU/day.

A link has also been suggested between bone damage and mitochondria damage, and a link to high levels of lactic acid have also been reported. The HIV medications related to these changes maybe nucleosides. This maybe a reason to use mitochondria protecting nutrients such as vitamins C and E, L-carnitine and co-enzyme Q.