Children’s body mass index (BMI) category in the first years of life was often carried through to adolescence, a German population-based study showed.
Most children stayed in the weight group they were in at age 5 through into ages 15 to 18, Antje Körner, MD, of the University of Leipzig, Germany, and colleagues reported in the New England Journal of Medicine.
Age 2 to 6 appeared to be a critical period: While 50% of those overweight (BMI standard-deviation score of 1.28 to <1.88) at 2 or younger achieved normal weight in adolescence, almost 90% of those who were obese (BMI SD score of 1.88 to <5) at age 3 were overweight or obese in adolescence.
The trajectory to obesity in the teen years followed a growth spurt from ages 2 to 6, with a 1.4-fold greater risk of overweight or obesity than seen among children with stable BMI in the preschool years.
High birthweight was a risk factor too, as 43.7% of those born large for gestational age were overweight or obese in adolescence. That corresponded to a 55% elevated risk of obesity in the teen years compared with other children.
The good news was that lower-weight preschoolers uncommonly became obese as teens.
Because teen obesity tends to carry over into adulthood, with metabolic and cardiovascular consequences, the findings have implications for identifying at-risk children based on early dynamics and patterns of BMI, Körner’s group noted.
“With regard to prevention, the clinical manifestation of obesity is a late starting point.” An annual increase of 0.2 or more in the BMI standard-deviation score during the preschool years “can be regarded as an early sign of ensuing obesity in adolescence that appears much earlier than the actual clinical manifestation of overweight.”
“A practical clinical implication of our study results would be surveillance for BMI acceleration, which should be recognized before 6 years of age, even in the absence of obesity.”
The researchers suggested tracking growth and weight patterns, particularly in those with maternal overweight or large-for-gestational-age status at birth, to prompt early intervention. “It is therefore important for healthcare professionals, educational staff, and parents to become more sensitive to this critical time period.”
The population-based study included 51,505 children with at least one measure of height and weight by age 14 and another at age 15 to 18, collected by pediatricians participating in the CrescNet patient registry at well-child or other office visits. The weight categories followed German national guidelines.
The findings were largely in line with prior studies, although those assessed a smaller age span or had limited sample size, the researchers noted. Studies that were well-powered missed the period from 2 to 7 years of age, “and hence began after the most pronounced weight gain had occurred.”
In an accompanying editorial, Michael Freemark, MD, of Duke University Medical Center in Durham, N.C., called the findings important, cautioning, however, that extrapolation to children in other countries is unclear, particularly in the developing world where the timing and magnitude of changes in BMI are often different from in Germany.
Another limitation was the inability to determine causality, he added, suggesting a clinical trial of early dietary intervention.
“We are now witness to an evolving epidemic of childhood obesity in the United States and other westernized countries … It is an ominous sign that the number of American children with the most severe and recalcitrant forms of obesity has increased progressively during the past 10 years. One hopes that interventions tailored to high-risk children at an early age can help to prevent or limit excess weight gain before obesity becomes irreversible.”
The study was supported by the German Research Council for the Clinical Research Center, German Federal Ministry of Education and Research, and Leipzig Research Center for Civilization Diseases (LIFE Child, supported by the European Union, the European Regional Development Fund, and the Free State of Saxony).
The CrescNet registry infrastructure was supported by grants from Hexal Germany, Novo Nordisk Pharma, Merck Serono Pharma, Lilly Deutschland, Pfizer Pharma, and Ipsen Pharma.
Körner reported financial relationships with the German Research Council, the European Regional Development Fund, the Federal Ministry of Education and Research, and Merck Serono, as well as non-financial support from Ferring Arzneimittel, Ipsen Pharma, and Eli Lilly.
Freemark reported grants from Rhythm Pharmaceuticals, the American Heart Association, and the Humanitarian Innovation Fund and European Commission, and personal fees from Springer Publishing.
Primary Source
New England Journal of Medicine
Secondary Source
New England Journal of Medicine
