Relationships of Bone Mineral Density to Whole Body Mass, Fat Mass and Fat-free Mass in Long-term Survivors of Acute Lymphoblastic Leukemia in Childhood

Bone Mineral Density in Survivors of Childhood Cancer: A Meta-Analysis

CONTEXT

There is an increasing population of childhood cancer survivors (CCS) at risk for treatment-related toxicities, including skeletal morbidities. Bone mineral density (BMD) is a proxy for bone health and reductions are associated with osteoporosis and fractures.

OBJECTIVE

To investigate bone health in CCS by conducting a systematic review and meta-analysis of BMD after completed treatments.

DATA SOURCES

We searched Medline, Embase, Cochrane, and Web of Science in May 2019 and updated in May 2023.

STUDY SELECTION

Studies reporting BMD Z-scores measured with dual-energy x-ray absorptiometry in CCS after treatment completion.

DATA EXTRACTION

We performed a pooled analysis of studies reporting BMD Z-scores and thereafter we analyzed studies comparing BMD in survivors and healthy controls. All analyses were performed based on the site of BMD measurement.

RESULTS

Of 4243 studies, 84 were included (N = 8106). The mean time off-treatment across the studies ranged from 2 months to 24 years. The overall pooled mean Z-score was -0.57 (95% confidence interval [CI] -0.59 to -0.55) in the whole-body, -0.84 (95% CI -0.86 to -0.83) in the lumbar spine, -0.79 (95% CI -0.81 to -0.77) in the femoral neck and -0.14 (95% CI -0.18 to -0.11) in the total hip. When comparing survivors with controls, BMD was significantly lower in survivors at all sites.

LIMITATIONS

English publications, study-level meta-analysis.

CONCLUSIONS

We showed a significant reduction of BMD Z-scores in CCS. Given the increased fracture risk already within -1 SD, these results emphasize the need for BMD surveillance and secondary prevention in CCS.

Sarcopenia in long-term survivors of cancer in childhood and adolescence: A cross-sectional study of calf muscle mass by peripheral quantitative computed tomography with an examination of the muscle-bone unit

BACKGROUND

Sarcopenia, a loss of systemic skeletal muscle mass (SMM), is prevalent in childhood cancer survivors and often accompanied by increased fat mass (sarcopenic obesity [SO]). We examined whether calf muscle cross-sectional area (CSA), measured by peripheral quantitative computed tomography (pQCT), can identify sarcopenia and SO in long-term survivors of pediatric acute lymphoblastic leukemia (ALL), and explored its relationship with adjacent bone geometry.

PROCEDURES

Calf muscle CSA and CSA Z scores at the 38% tibia in 70 subjects (median survival 15 years) were compared between sexes and ALL risk group, and their association with sarcopenia and SO evaluated. Relationships between bone strength and muscle mass were assessed further using linear regression and methods described by Schoenau et al. for evaluation of a functional muscle-bone unit.

RESULTS

A calf muscle CSA Z score of less than or equal to zero is 73.81% sensitive and 84.62% specific for detecting sarcopenia defined by height-adjusted appendicular lean mass measured by dual-energy x-ray absorptiometry. No significant difference in CSA Z scores was noted between sexes or ALL risk groups; however, Z scores were markedly higher in those without SO (adjusted odds ratio 0.529, 95% confidence interval [CI]: 0.340-0.824). Ratios of calf muscle mass to height and total bone mineral content at the 38% tibia are "sufficient" and consistent with estimated reference ranges for a healthy population.

CONCLUSIONS

CSA Z scores may represent a useful clinical measure of SMM and are predictive of SO in this population. Our results are supportive of a functional muscle-bone unit in long-term survivors of pediatric ALL.

Detecting Sarcopenic Obesity in Survivors of Pediatric Acute Lymphoblastic Leukemia: An Exploration of Body Mass Index and Triponderal Mass Index as Potential Surrogate Markers

Survivors of pediatric acute lymphoblastic leukemia (ALL) often have altered body composition secondary to treatment effects, including sarcopenic obesity (SO), which increases the risk of both metabolic complications and frailty. SO is difficult to detect without using advanced imaging techniques to which access is often limited. To explore whether common clinical indices can reliably identify the presence of SO in a cohort of long-term survivors of ALL, the discriminatory capacity of body mass index (BMI) or triponderal mass index (TMI, kg/m 3 ) for detecting SO was assessed. Thresholds of BMI and TMI associated with overweight or obesity status had poor sensitivity (<50%) and specificity for detecting SO. Total misclassification rates at these thresholds exceeded 50% and positive likelihood ratios were nonsignificant. Notably, TMI is more strongly correlated with elevated adiposity than is BMI in this survivor population ( R2 =0.73 vs. 0.57), suggesting further exploration is warranted. Our study is limited by the sample size, precluding detailed regression analysis. This study highlights the challenges of identifying SO in survivors of pediatric ALL using common clinical indices. Prospective evaluation of additional potential surrogate markers in survivors, in conjunction with the component features of SO, should be a key focus of future research.

The Influence of Body Composition on Bone Health in Long-term Survivors of Acute Lymphoblastic Leukemia in Childhood and Adolescence: Analyses by Dual-energy Radiograph Absorptiometry and Peripheral Quantitative Computed Tomography

BACKGROUND

The normal interrelationship of body composition with bone health is less clear in the context of disease. Survivors of acute lymphoblastic leukemia (ALL) exhibit sarcopenic obesity and osteopenia. The impact of body composition on bone health in such survivors was examined.

SUBJECTS AND METHODS

Survivors of ALL (N=74), >10 years from diagnosis, underwent dual-energy radiograph absorptiometry and peripheral quantitative computed tomography.

RESULTS

Whole-body bone mineral content (WB BMC) Z scores were greater in males than females, but WB BMC indices (WB BMC/height 2 ) were comparable (0.74±0.125 and 0.72±0.069, respectively). WB BMC index (I) and fat-free mass index correlated significantly with trabecular bone mineral density, only in males. Fat mass index and appendicular lean mass index showed no such correlations. WB BMCI and fat-free mass index also correlated, again predominantly in males, with measures of strength in both trabecular and cortical bone. WB BMCI also correlated strongly with trabecular number, thickness, and hole size, also only in males.

CONCLUSIONS

The results point to the need for enhancing muscle mass, measured by appendicular lean mass index, while reducing fat mass and maintaining good bone mineralization in long-term survivors of ALL to ensure the integrity of healthy bones.