Abstract LB9 - HAART-Associated Bone Mineral Loss through Increased Rate of Bone Turnover in Vertically HIV-Infected Children

LB9 HAART-Associated Bone Mineral Loss through Increased Rate of Bone Turnover in Vertically HIV-Infected Children

A. VIGANO, N. SALA, D. BRICALLI, G. CHIUIMELLO, and S. MORA*
L. Sacco Hosp. and Scientific Inst. H.S. Raffaele, University of Milan, Italy.

Background.Osteoporosis is a new complication described in HIV-infected adults receiving highly active antiretroviral therapy (HAART). Its etiology remains undefined and pediatric data are lacking.

Methods.Bone mineral density (BMD) of whole body and of lumbar spine (L2-L4) was assessed by DXA (Dual-Energy-X-Ray Absorptiometry) in 40 vertically HIV-infected children (HIV+) (age range 6.2 – 17.0 yrs): 35 on HAART and 5 naïve to any antiretroviral treatment (UT). Six HAART-treated children showed clinical evidence of lipodystrophy (LD). Markers of bone formation (N-terminal propeptide of type I procollagen, PINP and bone-specific alkaline phosphatase, BALP) and of bone resorption (N-terminal telopeptide of type I collagen, NTx) were also measured. Results were compared to those obtained in 314 healthy controls (HC) (age range 4.9 – 18.5 yrs). Differences between HIV+ and HC and within HIV+ were assessed by multivariate analyses, to control for confounding variables (age, sex and height).

Results.BMD values were lower for the spine (p=0.004) and for the whole body (p<0.0001) in HAART-treated children than in HC, whereas they were similar in UT and in HC. BMD for the whole body was lower (p<0.005) in HAART-treated children with LD than in UT patients (0.869 vs 1.060 g/cm2), while children on HAART but without LD had intermediate values (0.914 g/cm2). BMD values of the spine showed the same trend but no significant differences. The markers of bone formation (BALP and PINP) and of bone resorption (NTx) were similar among UT and HC children. On the contrary, BALP levels in HAART-treated children were higher (p=0.0007) than in HC and higher (p<0.05) than in UT. PINP values showed the same trend of BALP, but not at a significant level. Similarly, NTx urine levels in HAART-treated children were higher than in HC (p<0.0001) and higher than in UT (p<0.05).

Conclusions.Bone demineralization occurs in HAART-treated HIV-infected children, at risk not to achieve a physiological peak bone mass. The increased rate of bone turnover is the pathogenetic mechanism of BMD decrease. The severity of osteopenia seems to be related to adipose tissue redistribution.