Aging Attenuates the Association Between Coronary Artery Calcification and Bone Loss Among HIV-Infected Persons

Background:

 

Coronary artery disease and fragility fracture are important non-AIDS defining illnesses (NADI’s) that share similar risk factors. Coronary artery calcium (CAC) and bone mineral density (BMD) are key prognostic measures for these NADI’s. Some studies among HIV-uninfected persons (mostly in their sixth decade of life) show that detectable CAC is independently associated with low BMD, suggesting a possible common pathogenic pathway. We assess the relationship between CAC and BMD, which has not been well described among younger to middle-aged HIV+ persons.

Methods:

 

We studied participants with baseline CAC and BMD measures from a prospective cohort of HIV+ persons enrolled in the U.S.-based SUN Study during 2004-2006. CAC was determined using multislice computed tomography scans (Agatston score) and BMD was measured using dual X-ray absorptiometry on Hologic machines (g/cm², T-score). We used logistic regression to assess the association between detectable CAC (> 0 Agatston score) and BMD adjusted for known traditional and HIV-related risk factors.

Results:

 

                Among 472 participants (76% male, 30% non-Hispanic black, median age 41 years, median CD4+ cell count 432 cells/mL, 71% with HIV RNA <400 copies/mL), the majority (388, 82%) had no detectable CAC (0 Agatston score). In contrast, most participants had baseline osteopenia (252, 53%) or osteoporosis (48, 10%). In univariate analysis, participants with detectable CAC were more likely to have lower femoral neck and total hip T-scores, lower femoral, total hip, and lumbar spine BMD, and higher rates of osteopenia or osteoporosis (Table). After adjustment for age alone (Model 1), all associations were no longer statistically significant. However, adjustment for traditional risk factors excluding age (Model 2) and HIV-related variables (Model 3) failed to attenuate all associations.

Conclusion:

 

                We found that aging attenuates the association between detectable CAC and BMD in this cohort of younger to middle-aged HIV+ persons. Aging remains an important contributor to most NADI’s, and these data reinforce the importance of developing screening and prevention strategies for HIV+ persons of older ages given their excess disease risk across a wide spectrum of end-organ complications.