detected in The Netherlands. Postnatal, the secular trend is obvious for weight, height and BMI. In the third chapter, we explored whether short term changes in body composition, measured by total body water (TBW), as a result of rhGH treatment could be used to predict its growth effect after one year in children with growth hormone defi-‐ ciency (GHD) and SGA children. TBW is the volume of water in the human body. The Deuterium TBW method evaluates shifts from fat mass (FM) to fat-‐free mass (FFM) by measuring TBW. We investigated data of 88 GHD children and 99 SGA children who started treatment with rhGH. TBW and height were measured. After one year patients were divided into adequate and inadequate responders. In GHD and SGA children a sensitivity of 87% and 53% resp. and a specificity of 58% and 83% resp. were found. The positive predictive values for GHD and SGA children are 73% and 90% resp. The negative predictive values are 75% and 32% resp. We state that changes in body composition data measured by TBW are a valuable tool to correct-‐ ly predict the growth effect after one year in 75% of the GHD children, treated with rhGH, and are only useful in SGA children when the change in TBW is above the cut off value of 0.7 l/m2. In the fourth chapter, we investigated the growth pattern, expressed as BMI and weight for height values of SGA children, treated with rhGH treatment. It is known that the majority of SGA children show an accelerating weight gain, but no acceler-‐ ating length gain. Researchers suggest that low birth weight followed by rapid weight gain during early postnatal life is associated with long-‐term risks for central obesity. Those SGA children who not correct their length are treated with rhGH. Already at an early age both the GHD and the SGA children show abnormalities in body composition. While GHD children show an increased total body fat, SGA chil-‐ dren show a reduced body fat percentage. A previous nationwide study showed that treatment with rhGH barely changed the body composition, measured by the Deuterium total body water dilution method in SGA children. The mean change in BMI after 1 year of rhGH treatment is 0.00 kg/m2. The mean change in weight for height (SDS), after 1 year of rhGH treatment is 0.17 SDS. Apparently, BMI and weight for height of SGA children change during the first year of rhGH treatment, but only relative. Though, rhGH therapy does contribute to the prevention of the metabolic syndrome in SGA children, becauses it results in a shift in body composi-‐ tion towards an increase in FFM. In the fifth chapter, we describe the creation of a prediction model for the develop-‐ ment of obesity in childhood. This model is based on data of the Dutch longitudinal growth study, collected in 1995-‐1999, by Gerver et al, to estimate the change in Ponderal Index (PI) and BMI during the first four years of life. It became clear that the PI during the first year, as well as the BMI from the age of 1 year onwards, is changing for most children. This phenomenon can be partly ascribed to the regres-‐ 120
Proefschrift binnenwerk Manon Ernst_DEF.indd
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