The study, which involved over a thousand school students in Philadelphia, also suggested that body mass index (BMI) was as significant a factor in determining absenteeism from school as the hitherto known four main predictors—such as age, race, socio-economic status and gender.
The researchers found that overweight children were on average 20 per cent more absent than their normal-weight peers.
"At this young age, children are not necessarily experiencing the health problems that will likely confront them later in life unless serious intervention takes place," said Andrew B. Geier, a doctoral candidate in the Department of Psychology in the School of Arts and Sciences at Penn.
"However, they are missing school at a greater rate than their peers, setting themselves up for the negative fallout that accompanies absenteeism. What's keeping them from school, more than heath issues, is the stigma and the bullying that accompanies being overweight. Future research should explore this additional, very damaging side effect of being overweight," Geier added.
Previous studies have revealed that skipping school may lead to a number of problems like increased drug use, increased rates of pregnancy and poor academic performance. The four indicators of increased absenteeism among school children have traditionally been race, socio-economic status, age and gender.
But the present study has shown that BMI is a better indicator of poor classroom attendance than these traditional factors or any others.
During the study, the researchers attempted to control for the socio-economic differences among students by selecting inner-city schools that were homogeneously among the city's poorest.
More than 80 per cent of students at those schools were eligible for free and reduced-cost meal plans.
The findings have been reported in the journal Obesity.