www.hivandhepatitis.com

IAS 2011: Coronary Artery Calcification Linked to Bone Loss

Coronary artery calcification is associated with and low femoral bone mineral density (BMD), but no such link found with lumbar spine BMD, researchers reported at IAS 2011 in Rome.

As the population of people with HIV ages, a complex of adverse effects -- including lipodystrophy, organ disease, sexual dysfunction, cognitive decline, and non-infectious comorbidities -- are increasingly combining to create an "aging phenotype." The exact cause or causes of this complex are poorly understood, but the importance of this understanding grows.

Cardiovascular disease (CVD) and decreased bone mineral density are increasingly common complications as part of this aging phenotype, and there are reasons to believe that these problems might be related. Research has shown the presence of osteoblasts and osteoclasts (cells that produce and break down bone) in atherosclerotic plaques.

In addition, one prior study showed that women with severe low BMD (osteoporosis) were over 4 times more likely to have CVD than women with lesser bone loss (osteopenia), providing clinical evidence to support this hypothesis. Taken together, these findings suggesting the possibility of "cross talk" between these phenomena.

In an oral presentation at the 6th International AIDS Society Conference on HIV Pathogenesis, Treatment and Prevention (IAS 2011) being held this week in Rome, Giovanni Guardeli of the Metabolic Clinic at the University of Medina and Reggio Emilia in Italy presented results from a study investigating the possible correlation between coronary arterial calcification (CAC) and low femoral (thigh bone) or lumbar spinal BMD in people living with HIV.

The study looked at 681 HIV positive people with no prior history of CVD. Participants were divided into those with high or low amounts of coronary calcium -- an indicator of development of atherosclerotic plaques, referred to as CAC score. 

Results

• Men were more likely to have high CAC scores, comprising 88% of this group vs 70% of those with low CAC score.
• People with diabetes were over twice as likely to have very high CAC scores.
• In a univariate analysis:

o      There was a trend toward an association between high CAC scores a low femoral BMD, but it was not statistically significant.

o      There was no association between CAC and low lumbar spine BMD.

• In a multivariate analysis

o      There was no association between CAC score and femoral BMD when controlled for age and sex (Model 1).

o      When traditional CVD risk factors (e.g. smoking, diabete) were added to Model 1, people with high CAC scores were just over 2 times more likely to have low femoral BMD (Model 2).

o      When HIV disease factors (e.g. CD4 count, HIV viral load) were added to Model 2, people with high CAC scores were 2.33 times more likely to have low femoral BMD  (Model 3).

o      When measures of kidney and thyroid function as well as vitamin D levels were added to Model 3, however, there was no additional increased risk of low femoral CVD  (Model 4).

o      No association was found between CAC score and lower spine BMD using any of these models.

Given the complex, multi-factorial nature of this phenomenon, extensive research is needed to fully uncover the factors that contribute to it. Guardeli’s study, suggesting a link between two important components of an emerging "ageing phenotype," brings us closer to solving or at least understanding this vexing problem.

7/19/11

Reference

A Bellasi, S Zona, G Orlando, et al. Coronary artery calcification is associated with femoral but not with lumbar spine mineral density. 6th International AIDS Society Conference on HIV Pathogenesis, Treatment and Prevention (IAS 2011). Rome. July 17-20, 2011. Abstract MOAB0102.