Author: Lam, Pui-shan
Title: Measurement of subcutaneous fat thickness with ultrasound imaging technique and its comparison with body mass index, waist circumference and skinfold thickness
Degree: M.Sc.
Year: 2011
Subject: Ultrasonic imaging.
Obesity in children.
Obesity -- Diagnosis.
Body composition -- Measurement.
Hong Kong Polytechnic University -- Dissertations
Department: Department of Rehabilitation Sciences
Pages: xiv, 86 leaves : ill. ; 30 cm.
Language: English
Abstract: Background: The prevalence of obesity has increased very rapidly and has become a worldwide epidemic. It could happen in people of all age group, and affect one's physical, psychological and social status. In addition, it increases the economic burden of the healthcare system and society-at-large. Childhood obesity is reported to be highly correlated with adult obesity, and risk of obesity-related diseases tends to be life-long and higher amongst obese children. In Hong Kong (HK), measurements commonly adopted to reflect childhood obesity status are body mass index (BMI), waist circumference (WC) and skinfold thickness (ST). However, due to different growth rate of children, there is no common standard to define childhood obesity. Ultrasound imaging (USI) has become popular and proved to be effective in assessing adipose tissues, but the reliability and correlation of USI as an assessment tool is rarely investigated in HK children. Method: This was an exploratory study to evaluate the correlation among different body composition measurements and an intra-rater reliability study on USI measurements. 6 subjects were invited to take part in the pilot study. 38 subjects ranging from 6.67 11.92 years old were recruited using convenient sampling method from a local primary school for the main study. Anthropometric measurements including body weight (BW), body height (BH), WC and ST were measured. Subcutaneous fat thickness was measured by USI and skinfold caliper (SC) at 4 standardized sites including the subscapular (Ss), triceps (Tr), suprailiac (Si) and thigh (Th) region. All the measurements were obtained from the right side of the subjects and were taken by a single observer to avoid errors induced by different observers. The correlations between different measurements and intra-rater reliability of USI measurement were calculated using Pearson's correlation coefficients and Intraclass correlation coefficient (ICC) respectively.
Results: The mean age of the subjects was 8.84 ± 1.46 years old. The mean BMI was 18.47 ± 3.37 kg/m². 52.6% of the subjects had normal weight, 47.4% of the subjects were categorized as overweight and obese (as defined by BMI), respectively. The intra-rater reliability of USI measurement was good at all sites, ranging from 0.950 (Ss) to 0.993 (Si). The correlation of BMI and USI was good to excellent, with an average value of 0.813. The best correlation was at Si (r = 0.871, p < 0.01). The average value for the correlation of WC and USI was 0.816, with the best correlation at Si (r = 0.884, p < 0.01). The correlation of ST and USI was excellent, with an average value of 0.906. The highest correlation was at Th (r = 0.923, p < 0.01). Conclusion: This study demonstrated good to excellent correlation of BMI and USI measurement, good to excellent correlation of WC and USI measurement and an excellent correlation of ST and USI measurement. These suggested that USI could be used as an assessment tool to reflect body fat composition. According to the findings of the study, there was good intra-rater reliability of USI measurement. This implied that with sufficient training and standardized measurement procedures, USI is reliable and may be more favorable than other commonly used measurement tools in assessing childhood obesity. Further study on the inter-rater reliability of USI measurement, effect of duration of training for USI on the reliability of the measurement, the application of USI in assessing body composition in school-age children, as well as the calculation and translation of USI readings to corresponding BMI values are recommended.
Rights: All rights reserved
Access: restricted access

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