Prevalence and trends of thinness, overweight and obesity among children across europe

Resumen

Childhood obesity is one of the most serious public health challenges of the 21st century. The prevalence of excess weight has increased at an alarming rate. Globally, in 2016 the number of overweight children under the age of five, is estimated to be over 41 million. At individual level, genetic susceptibility determines the likelihood of a child developing obesity. However, at the population level, it is the non-genetic factors that determine the changes in the frequency of obesity, including epigenetics, lack of physical activity, inadequate nutrition, sedentary lifestyles, as well as other factors as psychological, social and environmental factors. Children with obesity are more likely to remain obese in adulthood with the consequent burden of chronic diseases including type 2 diabetes mellitus, high blood pressure, cardiovascular disease, cancer, among others. In addition, childhood obesity has also been linked to poor academic performance, social stigmatization, bullying, self-esteem deficit, depression and, generally, with deterioration of health-related quality of life. Frequently, malnutrition and obesity are managed as independent problems, however, both have a common origin in poverty and in the unhealthy dietary habits. In developed countries, it has been described that the highest rates of obesity occur in families with less income and a lower sociocultural level. In underdeveloped countries, especially in urban populations with access to certain western products, it is increasingly common to find, in the same household, obese adults along underweight children; this coexistence of overweight and underweight in the same environment is a phenomenon known as "the double burden households". Nonetheless, while childhood obesity has been extensively studies, underweight has received less attention, despite its association with several health problems. The influence of the financial crisis on the health of Europeans in general, is a controversy problem. In Europe, there is no study that has analyzed whether the financial crisis has had any impact on the prevalence of weight status, and if the childhood obesity epidemic has peaked. The literature in Europe on estimates of prevalence of weight status categories is considerable. However, there is an apparent lack of epidemiological surveys conducted in an appropriate approach, using a clear and transparent methodology. Nowadays, monitoring both underweight and excess weight trends across European countries using data objectively measured and obtained with comparable methods should be considered a public health priority. In response to these questions, this doctoral thesis is framed, whose main objectives are the following: - To present a clear, standardized, and precise methodology that allows comparisons of changes in weight status in children and adolescents in most European countries. - To evaluate the prevalence and trends of overweight and obesity in European children from 1999 to 2016 using a systematic methodology. - To evaluate the prevalence of thinness, overweight and obesity among Spanish schoolchildren in Cuenca from 1992 to 2017. - To provide prevalence trend estimates of underweight among children and adolescents in Europe from 2000 to 2017. To respond to these objectives, in addition to developing a protocol and three meta-analysis, we used empirical data from a series of studies carried out in Cuenca, (Spain) during the period 1992-2017. As a result of this work we conclude that: - The current prevalence of childhood excess weight is very high, but trends have plateaued in most European countries. - There are substantial differences between countries in the current levels and trends of childhood obesity, highlighting a significant north-south gradient. - During the crisis period (2007-2010) the prevalence rate of overweight and obesity were highest, especially in some southern European countries, such as Greece, Spain, Malta, Italy, or Portugal, where the effect of this crisis was more serious. -Although the prevalence of overweight and obesity are very high in some countries in southern Europe, they continue to show an upward trend in some countries of the Mediterranean region. - The epidemic of childhood obesity in Spain has remained relatively stable in the last two decades, showing a slight decrease in prevalence rates like those reported in other countries. - The prevalence of thinness shows a worrying upward trend in Spain, especially in the cohorts of children born around the years of the financial crisis. - In most European countries the prevalence of underweight is considerable (around 8-9%), particularly in Eastern Europe, and follows a slight upward trend over the last decade in both children and adolescents.