Association between energy expenditure and body composition in pre-school children

Abstract

The aim of my thesis was to assess the variability of EE and weight up the link between this variability and body composition in pre-school children (89 subjects). A further aim was to validate a wrist worn acelerometry (Actiwatch) against direct observation and compare two-points and multi-points calculation methods of total EE using DLW. Our results indicated that Actiwatch is valid and reliable for assessing physical activity (PA) pattern in children. In second study we observed that there was no significant difference between two sample points and multiple sample points to calculate total energy expenditure in pre-school children, while multi-samples gave more precise estimation of TEE than two samples. A considerable variation in resting metabolic rate (73.1%) and TEE (70.9%) was explained by body composition including fat mass and fat free mass. Sleep and PA pattern could make an additional contribution of 20.9% to variation of free-living TEE. Total and regional body composition obtained by dual energy X-ray absorptiometry (DXA) revealed that central FFM did not contribute more in variation of TEE and RMR than peripheral FFM. Although TEE was higher in boys, no significant gender difference was observed for RMR. Our results suggested that regional body composition is more associated to PA than total body composition. Cross-sectional data in this study did not allow us to determine the cause and effect manner of the association between PA and regional body composition. Increased watching TV was associated with greater body fat and it may happen by decreasing PA intensity and not by decreasing physical activity energy expenditure (PAEE) or Physical activity level (PAL). Even though, we die not observe any familial resemblance for PA and RMR between children and their parent, total body composition was more heritable than regional body composition at least in pre-school age children.EThOS - Electronic Theses Online ServiceGBUnited Kingdo