Researchers used longitudinal data from medical records, caregiver reports, and in-person and at-home measurements to track BMI changes and identify early signs of risk. The children were part of the national ECHO Cohort, a large-scale effort to understand environmental influences on child health.
Most children (89.4%) followed a typical BMI curve, which declined from ages 1 to 6 before gradually increasing. However, 10.6% of children exhibited an atypical pattern, where BMI remained steady between ages 1 and 3.5 and then rose sharply through age 9. This group was found to have a significantly higher likelihood of obesity by age 9, with an average BMI exceeding the 99th percentile.
The study also identified several early-life factors associated with increased obesity risk, including high birthweight, maternal smoking during pregnancy, high pre-pregnancy maternal BMI, and excessive maternal weight gain during pregnancy. These findings underscore the importance of prenatal and early-childhood health behaviours in shaping long-term outcomes.
“The fact that we can identify unusual BMI patterns as early as age 3.5 shows how critical early childhood is for preventing obesity,” said ECHO researcher Chang Liu, PhD, of Washington State University.
“Our findings suggest there are important opportunities to reduce childhood obesity, such as helping pregnant women quit smoking and manage healthy weight gain, as well as closely monitoring children who show early signs of rapid weight gain,” said Liu.
This study highlights the potential for early intervention to prevent obesity and reduce the risk of serious health conditions later in life.
Reference: Liu, Chang, M., et al. (2025) Early-Life Factors and Body Mass Index Trajectories Among U.S. Children in the ECHO Cohort. JAMA Network Open.
Disclaimer: This website is primarily for healthcare professionals. The content here does not replace medical advice and should not be used as medical, diagnostic, endorsement, treatment, or prescription advice. Medical science evolves rapidly, and we strive to keep our information current. If you find any discrepancies, please contact us at corrections@medicaldialogues.in. Read our Correction Policy here. Nothing here should be used as a substitute for medical advice, diagnosis, or treatment. We do not endorse any healthcare advice that contradicts a physician's guidance. Use of this site is subject to our Terms of Use, Privacy Policy, and Advertisement Policy. For more details, read our Full Disclaimer here.
NOTE: Join us in combating medical misinformation. If you encounter a questionable health, medical, or medical education claim, email us at factcheck@medicaldialogues.in for evaluation.