The foundations for being overweight and obese are often laid before a child even starts school. “This condition often manifests very early on in childhood. At the same time, the chances of obese young children returning to a normal weight in adolescence are less than 20 per cent. We found these effects in a large longitudinal study, which has direct implications for clinical practice,” says Professor Antje Körner, Professor of Pediatric Research at Leipzig University and head of the paediatric research unit at Leipzig University Children’s Hospital. In their study, the scientists tracked weight data of 51,505 children in the CrescNet registry between the ages of 0 and 18 years.
Early childhood is the critical age for weight acceleration
In their statistical analyses, the scientists found that, in the first one to two years of life, the chances of obese infants returning to a normal weight were barely 50:50. If the children were three years or older and obese, they only had a 10% chance – which means that 90% of those children remained overweight or obese into adolescence.
“Our data showed that the most excessive weight gain in those adolescents had occurred between two and six years of age,” explains Körner. “Their BMIs also continued to increase after this period, leading to a worsening of obesity each year.”
Birth weight and maternal weight also have an impact
Based on data of the LIFE Child study, it was also possible to show the importance of birth weight and maternal weight for a child’s risk of obesity. Almost half of babies who had been significantly long and heavy at birth had a higher BMI during childhood and adolescence, whereas fewer than 30% of children with normal or low birthweight were overweight or obese as adolescents. Children of overweight mothers also had a significantly higher risk of being overweight themselves during childhood than children of normal-weight mothers.
“Most overweight children and adolescents will remain overweight as adults. Of course the prevalence of overweight is even higher in adults, and not all overweight adults were overweight as children. However, if overweight develops in (early) childhood, it has a high likelihood of persisting – with all the associated consequences, such as the development of comorbidities in adolescence or young adulthood. An excessive weight gain in children, particularly those below the age of six, can be an early indicator of obesity later on. Growth and weight must be monitored from an early age by paediatricians, care givers and parents in order to identify children at risk,” explains Körner.
The study was supported by the German Research Foundation (DFG) Collaborative Research Centre on Mechanisms of Obesity (CRC 1052), the Integrated Research and Treatment Center AdiposityDiseases (IFB) and the Leipzig Research Centre for Civilization Diseases (LIFE Child).
Original publication in New England Journal of Medicine:
“Acceleration of BMI in Early Childhood and Risk of Sustained Obesity”; DOI: 10.1056/NEJMoa1803527
Dr. Katarina Werneburg