TOPLINE:

BMI trajectories at age 6 years vs ages 2, 10, and 14 years strongly predicted the risk for overweight and obesity in young adulthood (18 years). Notably, children with a high BMI and decelerated growth between ages 2 and 6 years had odds of overweight and obesity similar to those of peers with an average BMI.

METHODOLOGY:

• Researchers conducted a population-based prospective cohort study (Generation R) from foetal life onwards to identify specific age windows for BMI growth in childhood that are associated with overweight and obesity in young adulthood (18 years).
• They analysed data of 3528 singleton children (52.9% girls; 71.4% Dutch or European) born in Netherlands (2002-2006) who had data available on birth weight, gestational age, at least one BMI measurement during childhood (ages 2-14 years), and a BMI measurement in young adulthood (median age at measurement, 18.5 years).
• BMI SD scores, adjusted for sex and age, were calculated to classify children as having low or normal weight (< 1 SD), overweight (≥ 1 SD), or obesity (≥ 2) and grouped them into low, middle, and high tertiles of BMI at each age.
• Growth velocity across specific age windows (birth to 2 years and 2-6, 6-10, and 10-14 years) was categorised as accelerated, stable, or decelerated.

TAKEAWAY:

• Among children with overweight or obesity at ages 2, 6, 10, and 14 years, 32.6%, 54.0%, 57.4%, and 70.3%, respectively, continued to have overweight or obesity at age 18 years, and more than 66% had a recurring history of overweight compared with peers with a normal BMI.
• Each one-unit increase in the residualised BMI SD score at the age of 6 years was associated with more than twofold increased odds of overweight or obesity in young adulthood (standardised odds ratio [OR], 2.36; 95% CI, 2.04-2.72), and birth weight showed a weaker association (OR per birth weight SD, 1.20; 95% CI, 1.08-1.33).
• Children in the middle and highest birth weight tertiles who had accelerated BMI growth until 2 years of age had increased odds of overweight. Accelerated BMI growth between ages 2 and 6 years or 6 and 10 years was independently associated with increased odds of overweight and obesity regardless of the BMI tertile (P < .05 for both), with the highest odds observed in those with in the highest BMI tertile at age 10 years and accelerated growth (OR, 23.67; 95% CI, 9.44-59.35).
• Children in the highest BMI tertile at age 2 years with decelerated growth between ages 2 and 6 years had odds of overweight and obesity similar to those of peers with an average BMI.

IN PRACTICE:

"Optimizing and achieving remission of unhealthy BMI trajectories earlier in childhood may be a great opportunity for the prevention of overweight and obesity in young adulthood," the authors wrote.

SOURCE:

This study was led by Jasmin M. de Groot, Generation R Study Group, Erasmus MC, University Medical Center Rotterdam in Rotterdam, Netherlands. It was published online on May 21, 2026, in European Journal of Pediatrics.

LIMITATIONS:

The study population was relatively healthy and predominantly European, limiting the generalisability of the findings to other populations. Residual confounding could not be fully eliminated because of the observational study design. As the study was single‑centre and based on one birth cohort, the findings may have been influenced by regional, environmental, and generational factors.

DISCLOSURES:

The Generation R study received financial support from Erasmus MC; Erasmus University Rotterdam; The Netherlands Organisation for Health Research and Development; and the Dutch Ministry of Health, Welfare and Sport; and others. The study was supported by the European Research Council. The authors declared having no relevant competing interests.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.