Background

1
Factors Associated with Low Bone Mineral Density
(BMD) in a Large Cohort of HIV-Infected U.S.
Adults Baseline Results from the SUN Study
836
ET Overton1, K Mondy1, TJ Bush2, LJ Conley2, EM
Kojic3, K Henry4, J Hammer5, KC Wood6, KA
Lichtenstein7, JT Brooks2, and SUN Study
Investigators
1. Division of Infectious Diseases, Washington
University School of Medicine, St. Louis, MO. 2.
Division of HIV/AIDS Prevention, National Centers
for HIV, Hepatitis, STD and TB Prevention,
Centers for Disease Control and Prevention. 3.
Miriam Hospital, Providence, RI. 4. HIV Program,
Hennepin County Medical Center and the U of MN,
Minneapolis, MN. 5. Denver Infectious Disease
Consultants, Rose Medical Center, Denver, CO. 6.
Cerner Corporation, Vienna, VA. 7. University of
Colorado Health Sciences Center, Denver, CO, USA.
Comparison of Femoral Neck T-scores Among SUN
Study Participants and Matched Controls
Distribution of Low Bone Mineral Density In SUN
Study Participants
Distribution of Low Bone Mineral Density In SUN
Study Participants
Abstract (updated)
Results
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 7
U.S. clinics. 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 NHANES
matched for age, race, gender and BMI. Results
Data were available for 625 matched pairs.
Participants had a mean age of 41.0 years, 22
were female, and 28 were African American. Among
SUN subjects, 78 were currently on HAART and 58
had an undetectable HIV viral load. Osteopenia
(T-score -1.0 to -2.5) and osteoporosis (T-score
-2.5) were identified in 323 (52) and 61 (10)
subjects, respectively. In univariate analyses,
low BMD (T-score -1.0) was associated with
older age, male gender, unemployment, lower body
mass index (BMI), higher visceral to subcutaneous
fat ratio, duration since HIV diagnosis and any
stavudine use (all plt0.01). Osteoporosis alone
was associated with older age, non-white race,
lower BMI, current tobacco use, unemployment,
lower nadir CD4 cell count and longer duration
since HIV diagnosis (all plt0.05). In multivariate
analyses, low BMD was associated with older age,
male gender, lower BMI, unemployment and no
resistance training osteoporosis was associated
with older age, lower BMI, longer duration since
HIV diagnosis, and lower nadir CD4 cell count
(all lt0.05). When compared to the NHANES cohort,
the SUN Study cohort had significantly lower mean
T-scores at the femoral neck (-0.77 vs. -0.36,
plt0.01). At this site, the prevalence of low BMD
was higher in the SUN Study cohort (52 vs. 29,
plt0.01). 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 an issue of concern as they
age. HIV- and antiretroviral-related factors that
may affect BMD loss warrant longitudinal study.

• 625 HIV-infected subjects were matched to the
  NHANES cohort.
• Mean age 41.0 years.
• 135 women and 490 men.
• 378 Caucasians,173 African-American, 61
  Hispanics.
• Mean BMI 26.4 kg/m2.
• 466 subjects (75) were on HAART.
• 74 subjects (12) were ART naïve.

Low Bone Mineral Density
SUN study participants Mean -0.77
Matched NHANES subjects Mean -0.36
Osteopenia (51.7)
Osteoporosis (9.8)
Proportion
Univariate Analysis among the HIV-infected
Subjects
plt0.001
T-score
Background and Methods

• Mean T-scores were significantly lower in
  HIV-infected subjects.
• T scores (-0.77 vs. -0.36).
• At the femoral neck
• Osteopenia was present in 51.7 of HIV-infected
  subjects and 29.1 of the NHANES cohort.
• Osteoporosis was present in 9.8 of HIV-infected
  subjects and 1.0 of the NHANES cohort.

Normal (38.6)

• Background
• Osteoporosis is characterized by low bone mass
  leading to increased bone fragility and increase
  in fracture risk, particularly the vertebrae,
  hip, and wrist bones. Well characterized risk
  factors include race and gender (white and Asian
  women), early menopause, sedentary lifestyle,
  estrogen deficiency, family history of
  osteoporosis, heavy alcohol and caffeine intake,
  poor calcium intake, smoking, hyperthyroidism,
  renal failure, and corticosteroid use. In the
  general population, osteoporosis primarily
  affects postmenopausal white women.
• In the HAART era, low bone mineral density,
  including osteopenia and osteoporosis, has been
  identified as a common problem among chronically
  HIV-infected persons. Several studies have
  examined the relationship between bone mineral
  density and HIV. These studies have identified
  certain risk factors for low BMD including
  duration of HIV infection, history of weight
  loss, low BMI, smoking, and steroid use. The SUN
  study provides the opportunity to evaluate the
  association between HIV and low BMD among a large
  cohort of HIV-infected subjects in the current
  HAART era.
• Objectives
• To determine the baseline prevalence of low BMD
  (osteopenia and osteoporosis) in the SUN Study
  cohort.
• To describe factors related to low BMD in this
  cohort.
• To compare prevalence of low BMD in the SUN
  cohort with a healthy cohort from the NHANES
  matched for age, gender, race, and BMI.
• Methods
• HIV-infected Cohort The Study to Understand the
  Natural History of HIV/AIDS in the Era of
  Effective Therapy (SUN Study) is a 5-year
  prospective cohort study designed to examine risk
  factors for complications of treating HIV and
  longer survival. There are 682 HIV-infected
  adults enrolled from 7 clinic in 4 U.S. cities.
  At enrollment, all subjects were 18 years of age
  or older. Subjects were either ARV-naïve with a
  CD4 cell count between 100 and 500 c/mm3 or HAART
  experienced with a CD4 cell count gt100 c/mm3.
• Data Collection Sources of data included patient
  interview and laboratory data obtained at
  baseline study visit as well as abstraction of
  data from outpatient medical records. At
  baseline, all subjects receive a dual X-ray
  absorptiometry (DEXA) scan to determine bone
  mineral density. DEXA data were read at a single
  site (Tufts University).
• HIV-uninfected Cohort SUN Study subjects were
  matched for age, race, gender, and BMI to healthy
  persons from the National Health and Nutrition
  Examination Study III cohort. From DEXA scan
  results from the NHANES dataset, T scores from
  the femoral neck were available for comparison
  with the SUN Study cohort.
• Definitions We used definitions of osteopenia
  and osteoporosis developed by the World Health
  Organization based on the standard deviation (SD)
  between an individuals' BMD and the mean BMD at
  the time of peak bone mass among 30 year olds,
  adjusted for gender and race. Osteopenia is
  defined as a T score between -1 and -2.5 SDs
  below the mean. Osteoporosis is defined as a T
  score of less than -2.5 SDs below the mean. Low
  BMD includes all persons classified as having
  osteopenia or osteoporosis.
• Statistics Chi-square or Fishers exact tests
  used for categorical variables. Continuous
  variables compared using the Students t-test or
  Mann-Whitney U test, for normally and
  non-normally distributed data, respectively.
  Multivariate logistic regression to identify
  independent predictors of low BMD and
  osteoporosis from among factors significant in
  univariate analyses. All p values were
  two-tailed. SAS software was used for analysis.

Multivariate Analysis of Factors associated with
Low Bone Mineral Density
Conclusions

• There is a high prevalence of osteopenia and
  osteoporosis in the SUN cohort.
• These prevalence rates are much higher than
  those in a matched healthy cohort.
• Longer duration of time since HIV diagnosis and
  lower baseline CD4 cell counts in combination
  with older age and lower BMI may serve as useful
  markers for aggressive evaluation of BMD with
  DEXA scanning.
• The SUN study will provide longitudinal data to
  determine the evolution of BMD in HIV-infected
  subjects and the role of ART and to evaluate the
  development of fragility fractures.
• Acknowledgements We wish to gratefully
  acknowledge all SUN study investigators and their
  support staff, Cerner Corporation, and all of the
  study participants who have devoted their time
  and effort to this research endeavor.

Multivariate Analysis of Factors associated with
Osteoporosis
Continuous variables were categorized into
quartiles. For the BMI and CD4 cell count
variables, these values reflect the lowest
quartile. For the age and time since diagnosis
variables, these values reflect the highest
quartile
Visceral to subcutaneous fat ratio. Men only.
Women only.
The findings and conclusions in this poster
presentation are those of the authors and do
not necessarily represent the views
of the Centers for Disease Control and Prevention.