Children with NS were compared to age and sex matched healthy controls. Body composition and areal BMD (whole body, lumbar spine and hip) were assessed by DXA. Peripheral quantitative computed tomography (pQCT) scans were obtained at metaphyseal (4%) and diaphyseal (66%) sites of the tibia to determine volumetric BMD and bone cross-sectional geometry. Lifetime cumulative glucocorticoid exposure was calculated from medical records.
29 children with NS (55% male, age 10.7 卤 3.1 years) were compared to 29 healthy controls (55% male, age 11.0 卤 3.0 years). The children with NS were of similar height SDS to controls (p = 0.28), but were heavier (0.65 卤 1.28SDS vs 鈭?#xA0;0.04 卤 0.89SDS, p = 0.022) and had greater body fat percentage SDS (0.31 卤 1.01 vs 鈭?#xA0;0.52 卤 1.10, p = 0.008). Tibial trabecular and cortical vBMD were similar between the two groups but bone cross-sectional area (CSA) was significantly greater in children with NS at both the metaphysis (954 卤 234 mm2 vs 817 卤 197 mm2, p = 0.002) and diaphysis (534.9 卤 162.7 mm2 vs 463.2 卤 155.5 mm2, p = 0.014). Endosteal and periosteal circumferences were greater in children with NS than controls (both p < 0.01), resulting in reduced cortical thickness (2.4 卤 0.7 mm vs 2.8 卤 0.7 mm, p = 0.018), but similar cortical CSA (p = 0.22). The differences in cortical geometry were not statistically significant when weight was included as a confounding factor. There were no associations between cumulative steroid exposure, duration of NS or number of relapses and any bone parameter.
Tibial bone CSA is increased in children with NS. We speculate that this is a compensatory response to increased body weight. Defects in trabecular BMD were not identified in this cohort of children with NS.