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Bone Mineral Density in Adolescents Infected with HIV Perinatally or Childhood: Data from the NIH Intramural Program
Vijaya Thomas*1, J Purdy2, J Reynolds3, C Hadigan1, and R Hazra2,4
1NIAID, NIH, Bethesda, MD, US; 2NCI, Bethesda, MD, US; 3NIH, Bethesda, MD, US; and 4Natl Inst of Child Hlth and Human Devt, NIH, Bethesda, MD, US
Background: Altered bone health is a potential complication
associated with HIV and ARV. In 2 previous studies of tenofovir DF (TDF) -containing
salvage therapy we found low mean baseline bone mineral density (BMD) overall and
absolute BMD declines of >6% in 7 of 21 subjects. We designed this study to
measure BMD in a larger cohort of stable ARV-experienced HIV-infected
adolescents who acquired HIV in infancy or childhood that includes 6 of the 7
subjects in whom we previously documented BMD declines associated with TDF.
Methods: Subjects are enrolled in a prospective
observational study that includes dual-energy X-ray absorptiometry (DEXA) scans
of the lumbar spine. Baseline data and retrospective longitudinal data from 2
subjects are presented. Z-scores were calculated using appropriate standards. Laboratory
measurements include viral load, and vitamin D levels.
Results: From March 2007 to July 2008, 37 HIV+
subjects (34 perinatally infected, 3 transfusion-acquired) enrolled: 51% were
male, 59% non-black, mean (±SD) age 18±3.4
years, mean (±SD) cumulative ARV exposure 13.9±2.7
years. Mean (±SD) height z-score, BMI z-score, and lumbar spine BMD z-score
were –0.47±1.3, –0.02+1.1, and –0.43+1.1.
Mean (±SD) variability between repeat absolute lumbar spine BMD measurements was
0.88±0.7%; 51.4% had vitamin D insufficiency
(25-OH D <30 ng/mL), 38% of the subjects were currently on TDF, and 46% had
<50 HIV RNA copies/mL, but there were no significant associations between
vitamin D status, current treatment with TDF, or viral load with lumbar spine
BMD. Data from 2 subjects who experienced BMD declines associated with TDF are
shown in the graph in relation to the normal BMD for age. Both subjects first
received TDF when they were prepubertal, had durable virologic responses, entered
puberty before the age of 13 years (normal), and subsequently discontinued TDF
for renal toxicity. Subject #1 then experienced a partial recovery resulting in
absolute BMD 42% higher than his baseline with a z-score 0.99 lower. Subject #2
experienced full recovery while still on TDF, resulting in absolute BMD 51%
higher than baseline and the same z-score.
Conclusions: BMD was not affected by current TDF
therapy in this cohort. BMD improved over time in 2 subjects with a history of
BMD declines associated with TDF. The effect of TDF-containing HAART on BMD in
HIV-infected children appears to diminish as patients progress through puberty.
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