The greater the number of times people with HIV have switched their antiretroviral (ARV) drug regimens, the more likely they are to have lower bone mineral density (BMD).

After controlling for various other factors, a recent study found that, for each additional ARV regimen, BMD loss at the femoral neck was 0.011 grams per square centimeter and loss at the lumbar spine was 0.105 g/cm2. By comparison, women experience BMD loss of 0.005 g/cm2 per year during peri-menopause and 0.014 g/cm2 yearly during early post-menopause.

The study speculates that the most important factor influencing bone loss in this calculation is not drug toxicity but the greater number of episodes of elevated viral load that are connected to increased numbers of ARV drug regimens.

Aoife G. Cotter, MD, of University College Dublin in Ireland, who headed the study, says that when discussing bone loss in the HIV community, “positive health messages such as the importance of smoking cessation, reducing fall risk, and weight-bearing exercise are important.”