D I S C U S S I O N A N D V A L O R I Z A T I O N A D D E N D U M Already for many years we have been confronted with a worldwide increasing ten-‐ dency of children who become obese. At the same time, there is also evidence that obesity in childhood is on the basis of the metabolic syndrome in adulthood with the well-‐known pathology of hypertension, cardiovascular disease, diabetes melli-‐ tus and stroke. In this study we tried to gain better insight in the development of obesity, the possibilities of prevention and what obesity means in terms of body composition. The first question to study concerned the epidemiology of obesity. Although it is well-‐known that the origin of obesity in adulthood often has to be found in child-‐ hood, we did not find any increase in weight of the neonate born during the last decades. In other words, there is no increase in prenatal growth despite a mean increase in weight and length of the mothers known as the secular trend. In expla-‐ nation may it be stated that it is assumed that the intrauterine environment and the placental nutrition supply prevent the fetus from becoming overgrown to protect the mother herself. The placenta is not simply a passive conduit for nutrients but also responds to both maternal and fetal signals, altering placental transport and metabolic function1,2. On the other hand, it is described that maternal weight gain in early pregnancy has an influence on fetal weight probably mediated through raised placental mass3,4. Nevertheless, the general idea is that if a child has the tendency to achieve a weight and height outside the physiological borders, there might be a mechanism to restrict the further intrauterine growth as is shown in our data of birth weight and length gathered during the last years. The main concerns of obesity are the comorbidities like the metabolic syndrome and numerous psychosocial problems, which transfer obesity into a serious disease. Because the roots of obesity can often be found in childhood, it is significant to dis-‐ cern those children who are becoming obese just based on abnormal food intake often combined with a less degree of physical exertion and those who suffer from insulin resistance from birth onwards. The last group is especially recognized in the infants born after intra uterine growth retardation, the small for gestational age (SGA) children. Thanks to the longitudinal growth study during the first four years of age of a healthy Dutch population5, we were able to analyze the postnatal growth of individual children during this period. We realize that the reference population was taken ten years ago but at the same time these reference data compared to the last Dutch nationwide growth study show that the so-‐called secular trend has come to a stop for height. However, it did not come to a stop for weight. This tendency of becoming taller and heavier was originally an important indication of a population whose health gained thanks to better feeding and less disease. While the mean increase in height stopped already since more than ten years, weight gain is still going on for the population as a whole. For that reason a comparison with an older reference population it is signifi-‐ 107
Proefschrift binnenwerk Manon Ernst_DEF.indd
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