Endocrine Abstracts

Introduction: This study explores the role of different fat depots in the aetiology of abnormal glucose homeostasis in childhood ALL survivors treated with BMT and TBI using detailed body composition assessments with MRI and DEXA scanning.

Method: 52 (16–26 year old) childhood ALL survivors treated with (group 1, n=21, M=11) and without (group 2, n=31, M=13) BMT and TBI and 20 obese subjects (group 3, M=10) were investigated. Each had body composition assessment by single slice abdominal MRI at L4-5, DEXA scans, and standard oral glucose tolerance tests (OGTT). Outcome measures included DEXA total and android (central) fat%, MRI subcutaneous, visceral and intramuscular fat areas corrected for height, and insulin resistance (IR) by insulin area-under-the-curve (AUC) from OGTT. Comparisons between groups were made by ANOVA, with post hoc Scheffe test after logarithmic transformation if not normally distributed, and significance at 5%.

Results: Results were reported as mean (S.D.) or geometric means (range). Despite significantly lower total body fat% (P<0.001) and android fat% on DEXA (P<0.001), group 1 compared with group 3 had more cases of impaired glucose tolerance (IGT) or diabetes mellitus (DM) (n=9 vs 1, P=0.001) and higher IR (P=0.005). MRI results showed that group 1 compared with group 3 had more visceral fat (P<0.001) in female, as well as more intramuscular fat (P=0.003), less subcutaneous fat (P<0.001) but higher visceral-to-subcutaneous fat ratio (P<0.001) in both genders. Analysis of all participants showed significant correlation between visceral fat (P<0.001) and intramuscular fat (P=0.002) with insulin AUC.

Conclusion: Increased intramuscular fat, visceral fat and relative reduction in subcutaneous fat play a role in the aetiology of IGT and DM in childhood ALL survivors treated with BMT and TBI. MRI provides more detailed information in the assessment of body composition in chronic disease patients.