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Factors Associated with Low Bone Mineral Density in a Large Cohort of HIV-infected US Adults: Baseline Results from the SUN Study
Et Overton*1, K Mondy1, T Bush2, L Conley2, E Kojic3, K Henry4, J Hammer5, K Wood6, K Lichtenstein7, J Brooks2, and SUN Study Investigators
1Washington Univ Sch of Med, St Louis, MO, US; 2CDC, Atlanta, GA, US; 3The Miriam Hosp, Providence, RI, US; 4HIV Prgm, Hennepin County Med Ctr, Univ of Minnesota, Minneapolis, US; 5Denver Infectious Disease Consultants, Rose Med Ctr, CO, US; 6Cerner Corp, Vienna, VA, US; and 7Univ of Colorado Hlth Sci Ctr, Denver, US
Background: Low bone mineral density (BMD) is a common
metabolic complication associated with HIV infection. With increasing survival
in the era of HAART, there is continued interest in the factors influencing low
BMD in HIV-infected individuals.
Methods: The SUN Study prospectively follows a cohort of HIV-infected
patients at clinics in Denver, Minneapolis,
Providence, and St. Louis. At baseline, DEXA bone
densitometry and body composition, clinical data, and fasting laboratory values
were obtained on all subjects. Results were compared to persons from the National
Health and Nutrition Examination Study III (NHANES) matched for age, race, gender,
and BMI.
Results: Data were available for 562 matched pairs. Participants
had a mean age of 41.0 years, 22% were female, and 27% were African American. Among
SUN subjects, 79% were currently on HAART and 60% had an undetectable HIV viral
load. Osteopenia (T-score –1.0 to –2.5) and osteoporosis (T-score ≤ –2.5)
were identified in 262 (47%) and 59 (11%) subjects, respectively. In univariate
analyses, low BMD (T-score ≤ –1.0) was associated with older age, male
gender, unemployment, lower body mass index, higher visceral to subcutaneous
fat ratio, duration since HIV diagnosis and any stavudine use (all p ≤0.01). Osteoporosis alone was
associated with older age, non-white race, lower body mass index, current
tobacco use, unemployment, lower nadir CD4 cell count, and longer duration
since HIV diagnosis (all p ≤0.05).
In multivariate analyses, low BMD was
associated with older age, male gender, lower body mass index, unemployment,
and stavudine use; osteoporosis was associated with
older age, non-white race, lower body mass index, longer duration since HIV
diagnosis, and unemployment (all p <0.05).
When compared to the NHANES cohort,
the SUN Study cohort had significantly lower mean T-scores at the femoral neck
(–0.79 vs –0.36, p
≤0.01). At this site, the prevalence of low BMD was higher in the SUN Study
cohort (47% vs 31%, p ≤0.01).
Conclusions: In the HAART era, low BMD remains a significant complication
of HIV infection, more prevalent than found in the general population. In this large
cohort of HIV-infected persons, the majority of whom are virologically controlled,
the ramifications of low BMD will become a concern as they age. HIV- and ART-related
factors that may affect BMD loss warrant longitudinal study.
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