New York, Jul 9 (IANS): Despite several public health efforts to promote healthy behaviours and to improve living environments, childhood obesity is becoming more common in the US, according to researchers, including one of Indian origin.

The study, published in the journal Pediatrics, indicated that approximately 40 per cent of today's high school students and young adults had experienced obesity or could be categorised as overweight before leaving primary school.

"These worrying data indicate that the childhood obesity epidemic in the US continues to grow and get more serious. Our knowledge about effective interventions to fight this also seems limited," said researcher K.M. Venkat Narayan from Emory University in the US.

"We urgently need an aggressive national strategy for interdisciplinary research and public health to stem the tide of childhood obesity and its consequences in the US and worldwide," Narayan added.

For the study, the team analysed at what ages children are most likely to develop obesity and which children are at the highest risk.

They compared data on children entering kindergarten in 1998 and 2010 and followed them through fifth grade.

The data are nationally representative, so findings can be generalized to children growing up in the US.

They also found that children born in the 2000s experienced rates of obesity at higher levels and younger ages than children 12 years earlier, despite public health campaigns and interventions aimed at preventing obesity.