April 6, 2009

Vitamin D Might Blunt Tenofovir-Associated Bone Problems

Vitamin D supplements might protect people taking tenofovir (found in Viread, Truvada and Atripla) from elevated hormone levels, which can lead to bone mineral loss, according to a study presented at the 15th Annual Conference of the British HIV Association in Liverpool and reported by aidsmap.

As people are now living longer with HIV disease, a growing number are being diagnosed with osteopenia and osteoporosis, which occur when the bones lose the ability to absorb calcium. These conditions can occur in anyone, especially as people age, but several studies have found that people taking tenofovir might have a greater risk of bone mineral loss. It is not yet clear, though, how or why this may happen.

In order to explore these important questions, researchers at Kings College in London and Mount Sinai Hospital in New York City tested vitamin D and parathyroid hormone (PTH) levels in 45 HIV-positive men who were on ARV therapy. Vitamin D plays a powerful role in helping the body absorb calcium, and other studies have found low levels of the vitamin in people with HIV. The study’s authors theorized that low vitamin D levels could lead to an increase in PTH—a hormone that pulls calcium out of bone—potentially decreasing bone strength.

The research team found that 71 percent of the men had low vitamin D levels and 41 percent had elevated PTH levels. Further, they found that all of the patients with high PTH levels were taking tenofovir.

The researchers prescribed vitamin D supplements for 17 of the patients who had very low levels of vitamin D. Of the 14 who took the supplement as prescribed, all had increases in their vitamin D levels, and nine saw their PTH levels drop as well. Those who’d had the highest levels of PTH—again, all tenofovir-treated patients—actually had the greatest decrease in PTH levels after taking the vitamin D.

The authors caution that it is too early to definitively state that high PTH levels in people taking tenofovir are the primary cause of bone mineral loss, or that such individuals should all take vitamin D. Similarly, it is unclear whether vitamin D supplements actually reduce the risk of serious bone fractures in people living with HIV using tenofovir. The positive results, however, do warrant further study.

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David a/k/a "wishihF, NYC & Sweden, 2009-04-07 19:18:05
A few years ago I was diagnosed with Osteopenia. Treatment with bisphosphonates (Fosamax, etc) alleviated the problem. I now take daily vitamin D and calcium and have had no symptoms. Eliminating or reducing caffeine consumption (no more coffee!) may also help.