Co-morbid sarcopenia and low bone mineral density in young paediatric cancer survivors

Abstract

Background: Sarcopenia and low areal bone mineral density (aBMD) are prevalent musculoskeletal complications after paediatric cancer treatment. However, their relationship has not been examined in young paediatric cancers survivors. This study aimed to evaluate aBMD differences according to sarcopenia status and the risk of low aBMD Z-score in young paediatric cancer survivors with sarcopenia confirmed/probable.

Methods: This cross-sectional study included 116 paediatric cancer survivors (12.1 ± 3.3 years old; 42.2% female). Handgrip strength was used to assessed muscle strength. Dual-energy X-ray absorptiometry estimated aBMD (g/cm²) and appendicular lean mass index (ALMI, kg/m²). 'No sarcopenia' was defined when muscle strength was >decile 2. 'Sarcopenia probable' was defined when muscle strength was ≤ decile 2 and ALMI Z-score was > -1.5 standard deviation (SD). 'Sarcopenia confirmed' was defined when muscle strength was ≤ decile 2 and ALMI Z-score ≤ -1.5 SD. Analysis of covariance and logistic regression, adjusted for time from treatment completion, radiotherapy exposure, calcium intake, and physical activity, was used to evaluate aBMD and estimate the odds ratios (ORs) of low aBMD (aBMD Z-score < -1.0).

Results: Survivors with sarcopenia confirmed had significantly lower aBMD than those without sarcopenia at total body (-1.2 [95% CI: -1.5 to -0.8] vs. 0.2 [-0.2 to 0.6], P < 0.001), lumbar spine (-0.7 [-1.1 to -0.3] vs. 0.4 [0.0 to 0.8], P < 0.001), total hip (-0.5 [-0.9 to -0.2] vs. 0.4 [0.1 to 0.8], P < 0.001), and femoral neck (-1.0 [-1.4 to -0.6] vs. 0.1 [-0.3 to 0.4], P = 0.001). Compared with survivors with sarcopenia probable, survivors with sarcopenia confirmed had significantly lower aBMD Z-score at total body (-1.2 [-1.5 to -0.8] vs. -0.2 [-0.7 to 0.4], P = 0.009), total hip (-0.5 [-0.9 to -0.2] vs. 0.5 [-0.1 to 1.0], P = 0.010), and femoral neck (-1.0 [-1.4 to -0.6] vs. 0.1 [-0.5 to 0.7], P = 0.014). Survivors with sarcopenia confirmed were at higher risk of low aBMD Z-score at the total body (OR: 6.91, 95% CI: 2.31-24.15), total hip (OR: 2.98, 1.02-9.54), and femoral neck (OR: 4.72, 1.72-14.19), than those without sarcopenia. Survivors with sarcopenia probable were at higher risk of low aBMD Z-score at the total body (OR: 4.13, 1.04-17.60) than those without sarcopenia.

Conclusions: Young paediatric cancer survivors with sarcopenia present higher risk of low aBMD. Resistance training-based interventions designed to mitigate osteosarcopenia in this population should be implemented at early stages.

Keywords: Bone health; Cachexia; Childhood cancer; Exercise; Muscular health.

Figure 1

Sarcopenia status classification algorithm for identifying subjects with no sarcopenia, sarcopenia probable or sarcopenia confirmed (following the criteria of the sarcopenia definition stated by the EWGSOP2 ³⁰ ). Muscle strength was compared with age‐ and sex‐specific reference values of healthy young population by the FitBack network. Using international reference data from the Bone Mineral Density in Childhood Study, age‐ and sex‐specific ALMI Z‐score was calculated. ALMI, appendicular lean mass index.

Figure 2

Differences in age‐, sex‐ and race‐specific areal bone mineral density (aBMD) Z‐score according to sarcopenia status in young paediatric cancer survivors. Data are presented as adjusted means and confidence intervals (95%). Half violin plots show the distribution within sarcopenia status. Significant differences (adjusted P < 0.05) between sarcopenia status are shown in bold by analysis of covariance. Analyses were adjusted for time from treatment completion to baseline evaluation (years) and radiotherapy exposure (yes/no). Grey dashed line indicates the cut‐off point for low areal bone mineral density according to van Atteveld et al. (2019).