Washington: Teenaged boys from well-off Chinese families who say they are physically active and eat plenty of vegetables but few sweets, are more likely to be overweight, says a new study.

The study is one of the first to examine how weight among Chinese adolescents relates to factors like sleep duration, physical activity, diet and general demographics. Most of what the research team found runs counter to western trends.

"Findings from this large cohort of data on Chinese youth suggest that weight-related correlates might play different roles in Chinese culture than they do in western cultures," said study co-author Ya-Wen Janice Hsu, research assistant in preventive medicine at the University of Southern California.

"This suggests that influences on obesity are society-dependent, and assumptions based on western societies may not be applicable to Chinese populations," adds Janice Hsu, reports the American Journal of Health Behaviour.

As in the US and Europe, teens in China who sleep fewer hours and participate in more sedentary activities like watching TV are more likely to be overweight. But that's where the similarities end, according to a Southern California statement.

In China, parents with more education and more money are more likely to have obese children, whereas the same circumstances are related to a lower body mass index in western countries.

Chinese boys are more likely to be overweight than Chinese girls. In the US, boys are just as likely as girls to be overweight.

Chinese adolescents who reported frequent consumption of vegetables and infrequent intake of sweets and fast food are more likely to be overweight, the study says.

The analysis is based on 9,023 questionnaires submitted by randomly selected middle school and high school students in seven of China's most populated urban areas.

(Agencies)