Background:  Decreased bone mineral density appears to be a prevalent metabolic complication in HIV-infected children treated with HAART. However limited data are available regarding progression of osteopenia in children over time as well as its relationship with bone turnover markers. Consequently, our objectives were to determine the progression of bone mineral density over time in HIV-infected children. To evaluate some metabolic markers of bone formation and resorption with regard to bone mineral density. To assess the possible association of bone mineral density with antiretroviral therapy.

Methods:  A prospective study was performed by sequential Dual-Energy X-ray Absorptiometry (DEXA) (HOLOGIC QDR 4500/W). Only children with 2 DEXA scans were included. Osteopenia was defined as a z-score of <-1 for lumbar spine (L1-L4). Bone turnover markers were determined by the time the second DEXA was done. They included serum vitamin D 25, PTH, osteocalcin, and urine deoxypyridinoline, N-terminal telopeptide of type I collagen (NTx) and calcium/creatinin ratio. Student's t and chi-square were used for comparisons of group means and percentages.

Results:  In all, 35 vertically HIV-infected children underwent 2 DEXA scans with a median interval of 13 months (range 10 to 19). Median age was 129 months (58 to 219); 20 children were prepubertal (Tanner I); 30 patients were given HAART (28 PI-based, 2 PI-sparing regimen with NNRTI), 2 with 2 NRTI and 3 without therapy. Median time on HAART at first DEXA was 62 months (16 to 69); 73% of HAART-treated children had undetectable plasma viral load. Mean z-score at baseline was - 0.6 plus or minus 1.27 and 40% were osteopenic (2 < -2.5 z-score). There were no significant differences in the proportion of children with osteopenia (45%) nor in the z-score (-0.56 plus or minus 1.33) at second DEXA. There was a trend to a higher decrease of bone mineral density in children treated with PI-containing regimen (p = 0.06). Markers of bone resorption (urine deoxypyridinoline, NTx, calcium/creatinin) were significantly greater in osteopenic children.

Conclusions:  Decreased bone mineral density is prevalent in HIV-infected children treated with HAART.  No progression in bone mineral density over a median of 13 months have been observed. Bone resorption markers are significantly increased in osteopenic children.

Keywords: osteopenia; pediatrics; metabolic complications