Chapter 1b: Height, Weight, Puberty and AdiposityBody Mass Index, Weight-for-Length/Height and Obesity

With increasing prevalence of overweight and obesity the evaluation of the relationship of body weight to body height using body mass index (BMI) has spread universally also in children.In youngest children, maximally up to the age of 5 years only a relationship weight-for-length/height is used. In children the values of BMI are markedly dependent to the age and are specific for gender. Therefore utilization of growth reference is critical for assessment of health and nutritional status of children. In addition to the national growth references for children up to 19 years growth references WHO 2007, CDC 2000 and IOTF 2000 are mostly used. The WHO growth standards for children 0 – 5 years old were published in 2006. International comparisons of the evaluation of overweight and obesity are difficult due to the lack of consent of criteria used. In children after birth and during first year the percentile curves of BMI increase very markedly, but then they decrease. The second rise in BMI curve, i.e. adiposity rebound (AR), occurs between 5 and 7 years. An early AR is associated with an increasing risk of overweight. The secular trend of increased height and accelerated growth are probably responsible for shift of AR at earlier age. Until present overweight and obesity were the problem especially in high-income countries, overweight and obesity are now on the rise in low- and middle-income countries, particularly in urban settings. Selected studies from developed countries indicate, that this trend is finished.

Keywords: Acceleration, Adiposity, Body mass index, Gender, Growth, Obesity, Overweight, Prevalence, Rebound, Secular trend, Weight-for-length/height.