By Michael Smith, North American Correspondent, MedPage Today Published: September 12, 2010
- Explain to HIV-positive patients that additional studies add to the weight of evidence that vitamin D deficiency and bone loss are common, requiring evaluation and treatment. Note that seasonality should be considered when testing for vitamin D levels.
- Note that these studies were published as abstracts and presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.
BOSTON — People with HIV are at high risk for vitamin D deficiency, according to result of two studies presented here.
In a cross-sectional cohort study of 147 Spanish patients, nearly three-quarters had serum levels of 25-hydroxy vitamin D (25(OH)D) that were below 30 micrograms per liter (µg/L), according to Jose Luis Agud, MD, of Hospital Severo Ochoa in Madrid.
And in a clinical cohort of 395 patients in Lille, France, 90% tested below 30 nanograms per liter (ng/mL) and 41% were below 15 ng/mL, Armelle Pasquet, MD, of the University Hospital Center of Lille, and colleagues, reported at the Interscience Conference on Anti-microbial Agents and Chemotherapy (IAAC) in Boston, Mass.
The Spanish study, in particular, is surprising, Agud told MedPage Today. "We didn't expect vitamin D would be a problem in Spain," he said, because levels of sunshine are high and the use of sunblock is relatively low. The finding "came to our surprise," Agud said. (from Jules: apparently, Spanish people stay inside because of the fear instilled that the sun can cause skin cancer, so since it can be hot & sunny there perhaps that is the reason for such bad vit D levels, as told to me by a researcher here at ICAAC)
The Spanish study defined vitamin D deficiency as 25(OH)D <20 µg/L. In the French study, vitamin D deficiency was defined as around 15 ng/mL.
The issue is important because vitamin D deficiency is thought to play a role in bone loss in people with HIV, according to Laurent Kaiser, MD, of the University Hospital Geneva, a member of the ICAAC conference program committee who was not part of either study.
Kaiser told MedPage Today that he routinely prescribes vitamin D supplements to his HIV-positive patients, even if they are not deficient.
Indeed, a third study here confirmed the risk of bone loss among those with HIV. Researchers led by Anna Bonjoch, MD, PhD, of University Hospital Germans Trias i Pujol in Barcelona, that nearly a third of a cohort of 391 HIV patients had progressive bone loss.
Bonjoch and colleagues found that 12.5% of the cohort progressed from normal to osteopenia, and 15.6% went from osteopenia to osteoporosis. If only the 105 patients with more than five years of follow-up were assessed, they found, 47% had a loss of bone mineral density, with 18% developing osteopenia and 29% osteoporosis.
Analysis of the Spanish cohort, Agud said, turned up some obvious risk factors for deficiency and some that were less obvious.
For instance, he and colleagues found, there was clear seasonality, with higher risk for deficiency in the winter and spring and a lower risk in summer and fall. When spring measurements were compared with those taken in summer, the odds ratio for deficiency was 8.2, with a 95% confidence interval from 3.3 to 10.5, which was significant at P=0.0001.
On the other hand, Agud said, the researchers are at a loss to explain why their analysis showed that people who acquired HIV through heterosexual contact had a higher risk of deficiency — a significant odds ratio of 2.54 — than injection drug users.
They also found that use of the non-nucleoside reverse transcriptase inhibitor nevirapine (Viramune) was associated with a protective effect.
On the other hand, the French study found that use of non-nucleoside reverse transcriptase inhibitors was correlated with lower levels of 25(OH)D — although the correlation did not reach significance for any particular drug, Pasquet told MedPage Today.
Using a cut-off of about 15 ng/mL as their definition of vitamin D deficiency for the French cohort, Pasquet said, 41% of her study population was deficient.