Changing curves. Monitoring growth of children and adolescents in The Netherlands

Background: Monitoring human growth is important. It is used to detection of abnormal growth trajectories of children, which may reflect nutritional problems or underlying illness. In a larger population, it can provide information about the health status of this population, for example the prevalence of overweight and obesity, or the mean height. In The Netherlands, national growth studies have been carried out every 10 to 15 years since 1955. These large, nationwide studies allow comparison of height and weight of Dutch children over time. Since 1997, the growth studies also focus on Turkish and Moroccan children living in The Netherlands. In 2009, the Fifth Dutch Growth Study was conducted. This thesis presents the main results. Methods: Data for the Fifth Dutch Growth Study were collected in 2008-2009. Trained health care professionals measured height and weight and recorded background characteristics of 10,030 Dutch children, 2,548 Turkish and 2,594 Moroccan children aged 0-21 years. Results: We found that the mean height of Dutch children has not changed since 1997. At age 21, Dutch boys were on average 183.8cm and Dutch girls 170.7cm. The mean height of Turkish and Moroccan children living in The Netherlands has increased since 1997, but they are still 6 to 7 cm shorter than their Dutch peers. In 2009, 14% of Dutch children aged 2-21 years was overweight, 2% obese and 0.6% severely obese. Compared to 1980, this was a twofold increase in the prevalence rate of overweight, a fivefold increase in obesity, and sevenfold increase in morbid obesity. This indicated that not only the proportion of children with overweight increased, but also the severity of this overweight. Among Moroccan children living in The Netherlands, the prevalence rates for overweight, obesity and severe obesity were two to three times higher than among the Dutch. The highest rates were found in Turkish children: two to five times higher than in Dutch children. Since 1980, the prevalence of thinness decreased in children of Dutch, Turkish and Moroccan origin. Conclusion: The Dutch are the world’s tallest population. The secular increase in height of Dutch children has come to a halt after 150 years. It is not completely clear why the Dutch have stopped growing taller. They might have reached the optimal height distribution. Alternatively, growth promoting environmental factors may have stabilized over the past decade, prevention the population from reaching its full growth potential. Despite efforts to reduce overweight and obesity figures in The Netherlands, childhood overweight and obesity rates in 2009 were higher than in 1997. The large differences in prevalence rates between children of Dutch, Turkish and Moroccan origin underline the need for tailored approaches targeting high risk groups in the battle against overweight an obesity