Washington: Scientists have found an effective way to fight the epidemic of childhood and adolescent obesity.
They suggest a simple step that might help cut the problem down to size: start school sooner.
“Early admission to a school environment might have a long-term protective effect in terms of adolescent girls’ propensity to obesity,” according to the study.
The researchers analyzed data on nearly 6,000 girls from the National Longitudinal Survey of Youth, which included when they started school and their body mass index (BMI) from ages 12 to 18.
They found that girls who were born a month or less before the cutoff date for school enrollment — and so started school when younger than most of their classmates — were significantly less likely to be overweight during adolescence than those who were born during the month after cutoff.
Children who enrolled in school a year later than when they first became eligible similarly were more apt to be overweight than those who started on time.
The researchers did not find a comparable effect for adolescent boys.
Why school entrance age should influence weight 10 years later is not clear from the data, said lead study author Ning Zhang, Ph.D., of University of Rochester School of Medicine.
One possibility is peer effect: “Within any grade, younger girls may be exposed to relatively older friends, who are more careful about their weight and physical appearance,” she said.
Girls who are young for their grade have earlier exposure to this information and participate in more advanced physical exercise regimens as well.
The study appeared online in the Journal of Adolescent Health.