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Background:  Reduced bone mass is a frequent finding in HIV-infected children on HAART. The role of HIV exposure or of ART in causing the reduction of bone mass in HIV-infected children is still unclear.

Methods:  In this cross-sectional study, 39 HIV-infected children (aged 5.9 to 19.4 years; 22 girls, 17 boys) on HAART containing lamivudine (3TC) + stavudine (d4T) + 1 protease inhibitor (PI) were included in the study. HIV patients were divided into 2 groups according to their age (group A < 10 years, n = 9; group B ≥ 10 years, n = 30). Bone mineral content (BMC) and bone mineral density (BMD) were measured at the lumbar spine by dual-energy x-ray absorptiometry. BMD measurements were also expressed as standard deviation score from reference population (z-score). As control group, 166 healthy volunteers, ranging in age from 5.7 to 19.9 years, were studied. Multivariate analyses were performed to compare bone mass measurements of HIV and controls, correcting for the effect of confounding variables. The relationship between z-scores and age was evaluated by simple correlation analysis.

Results:  HIV-infected children reached HIV RNA < 400 copies/mL within 1 to 3 months after the beginning of HAART and maintained control of viral replication during HAART exposure. Exposure to HAART of group A was not different from that of group B (65 ± 7 months, and 68 ± 8 months, respectively). Patients of group A showed a mean (SD) BMC value of 14.3 g (1.8), and BMD value of 0.670 g/cm² (0.030). Patients of group B showed a mean (SD) BMC value of 35.4 g (11.3), and BMD value of 0.962 g/cm² (0.174). Multivariate analyses did not show significant differences in both BMC and BMD measurements between group A patients and controls. On the contrary, BMC and BMD measurements of group B patients differed significantly from those of controls (p = 0.02 and p = 0.0081, respectively). Age and BMD z-scores showed an inverse relationship (r = –0.30).

Conclusions:  Older children, despite a duration of HAART similar to that of younger children, showed lower bone mass measurements than did the controls. These data indicate that the duration of HIV infection before HAART may play an important role in determining low bone density.

Keywords: Bone mineral density; Bone loss; HAART