Use Of Ultrasonography In Body Composition Assessment In Cystic Fibrosis And Pediatric Patients

Abstract

PURPOSE: Body composition is an important indicator of medical status for certain diseases. Determining the best body composition method has been difficult for pediatric and cystic fibrosis (CF) patients. Ultrasound may represent an alternative to skinfold and bioelectrical impedance (BIA) techniques. The study was performed to determine how comparable ultrasound is to skin caliper and BIA assessments. METHODS: Ninety individuals were randomly selected during routine office visits to undergo body composition determination (age 13.0 yrs, range 5-31 yrs; 52M). 18 individuals had CF (13M), including all patients over 20 yrs. Percent body fat was determined by ultrasound (US-BF) using Body Metrix BX2000, skinfold (SF-BF) using Lange calipers, and BIA (BIA-BF). 4-site measurements (bicep, tricep, subscapular, suprailiac) were determined for both ultrasound and skinfolds. Spearman coefficients were determined between US-BF and other techniques. Values are expressed as mean±SD with significance set at p<0.05. RESULTS: US-BF was 24.5±6.7%, which correlated to SF-BF (24.4±6.8%, p<0.05), as well as BIA-BF (20.0±9.0%, p<0.05). Females had a higher percent body fat than males (SF-BF: 29.6±4.3% vs 20.6±5.7%, p<0.001). The US-BF for non-CF correlated to BIA-BF (r=0.71, p<0.05), as well as SF-BF (r=0.79, p<0.05). The US-BF in non-CF females correlated with BIA-BF (r=0.68, p<0.01) and with SF-BF (r=0.79, p<0.001). Similar findings were seen with non-CF males (BIA-BF: r=51, p=0.001; SF-BF: r=0.53, p=0.001) as well as CF females (BIA-BF: r=0.99, p=0.001; SF-BF: r=0.90, p=0.38). For CF males, US-BF was not correlated with BIA-BF (0.50, p=0.097) or SF-BF (r=0.39, p=0.21). CONCLUSIONS: For the non-CF group and CF females, US-BF correlated with both SF-BF and BIA-BF. US-BF did not appear to correlate as well as other techniques for individuals with low body fat, as seen in the males (both CF and non-CF). Ultrasound appears to be correlated with other techniques for body composition in non-CF children and CF females. Ultrasound may be an acceptable alternative for use in selected pediatric populations. However, ultrasound did not offer comparable measurements, when used on CF males. Additional studies are needed to determine the utility of ultrasound on extremely low fat individuals and CF patients.