Background: In recent years, obesity has been on the rise worldwide in general, but especially among children. Various developments are contributing to this phenomenon. On the one hand eating habits are changing with far too much sugar and high-fat food being consumed. At the same time, physical activity is decreasing sharply as children spend a lot of time in front of their smartphones or other technical devices. This thesis is part of the study “Health and Academic Performance with Happy Children (HAPHC)”. This study deals with the effects of a school-based physical activity intervention on measures of health and academic achievements in primary school children. It also aimed to quantify the degree of obesity by direct measures of subcutaneous adipose tissue (SAT) by ultrasound to generate reference values for children aged 6-11 years. Aims and Objectives: This thesis deals with the measurement of overweight and obesity in children, more specifically with the amount and distribution of subcutaneous adipose tissue (SAT). The aim of the thesis was to establish reference values for subcutaneous fat in children aged 6 to 11 years measured by ultrasound. In addition, the thesis describes the method of measurement using bright (B)-mode ultrasound and highlight the weaknesses and strengths of this measurement in comparison to other body indices. Methods: For the current thesis, data were collected in three elementary schools in Graz. The age of the children was between 6 and 11 years. Subcutaneous fat was measured at eight standardized sites. Bright-mode ultrasound was used to measure the thicknesses of the subcutaneous fat layers at these eight sites. The results were then broken down by age group and sex. In addition, the results of the SAT measurements were presented for the eight sites and for the total sum in percentiles. This should enable a simple classification of the amount of subcutaneous fat and to compare different samples with each other. Results: SAT was measured in 404 children. and was then broken down by age and sex. For comparisons, the results were presented in percentiles. Not only the respective measured point, but also the sum of all 8 measured points (DI) is presented in percentiles. The average of the total sum of the 8 measurement points for all age groups was DI = 65.14 mm ± 41.97 mm for boys and DI = 76.78 mm ± 39.34 mm for girls. Girls were shown to have a significantly higher amount of SAT and the thickness of the measured SAT increased with increasing age. In addition, it could be shown at which of the 8 measuring points the most subcutaneous fat is located and which sites correlate best with the BMI. The highest BMI correlation was found for the upper abdomen (UA) (r = 0.902, p < 0.05) and lower abdomen (LA, r = 0.896, p < 0.05). While the SAT measures differed significantly between girls and boys, no differences were found in anthropometric measures and body indices. Conclusion: This diploma thesis shows a detailed breakdown of subcutaneous fat values measured at eight different sites in children aged six to ten years. The ultrasound measurement method proved to be an excellent method in terms of reliability and reproducibility. The inter-rater reliability was very high with an ICC of 0.998 (95% CI 0.980 - 0.999). Intra-rater reliability was also very high, with an ICC of 0.994 (95% CI 0.983 - 0.998). It is also possible to visualize tissue boundaries of 0.1 - 0.2 mm with ultrasound, which underlines the extremely good accuracy of the method. Because it is also inexpensive, portable and quick to perform, the method has great potential for determining body composition and measuring subcutaneous fat. As other methods, such as the BMI, are even faster and easier to use, it is difficult to imagine that this method will become established across the board in the next few years. However, it is certainly a very good alternative in certain areas, such as top-class sport or for doctors.
Subcutaneous adipose tissue measured by ultrasound: reference values for primary school children
Hönes, P. (Author). 2025
Student thesis: Diploma thesis