Children of migrants to Chinese cities have lower rates of obesity than youngsters in more affluent established urban families, said a new study.
Large-scale migration sees millions of Chinese families leave the countryside and settle in the country's biggest cities in search of economic prosperity.
‘Prevalence of childhood obesity in resident city children was 20% compared to 14.3% among migrant children in China.’
Birmingham's research shows a trend that is the reverse of what is generally found in Western countries, where children from families in wealthier, more educated social classes tend to be fitter and slimmer than their counterparts in lower-income families.
They suggest that the Chinese Government could have an opportunity to keep obesity rates down among rural-urban migrants and those with lower household income and education by introducing food and physical activity policies.
Researchers worked with experts from the Guangzhou Center for Disease Control and Prevention to study 9,917 children aged between five and 12 in the city of Guangzhou, in southern China.
The team's research showed that the prevalence of obesity in resident children was 20% compared with 14.3% in migrant children. It is the first study to compare childhood obesity in urban migrants with city residents.
Migrants now comprise up to 50% of the population in major cities across China. In general, they tend to have lower levels of income and education than city residents.
Professor KK Cheng, Miranda Pallan, Bai Li and Peymane Adab, from the University of Birmingham and Dr. Weijia Liu, Wei Liu and Rong Lin of Guangzhou Center for Disease Control and prevention published the results of their research in BMC Public Health
Professor Peyman Adab, Professor of Chronic Disease Epidemiology & Public Health, said: "The increase in obesity observed among boys and girls in Guangzhou is opposite to that seen in developed countries and may be due to the current stage of economic development in China.
"There is an opportunity to apply lessons from countries at a more advanced stage of the obesity epidemic. Rural-urban migrants and those with lower household income and education have lower rates of obesity, which could be maintained with the introduction of government food and physical activity policies."
The study found that the obesity among resident urban children was higher in boys than compared with girls. It also increased as children grew older and per-capita household income and maternal education increased.
Over a third of 9-12 year old boys from higher income households were overweight or obese; a rate which is similar to that seen in the West. The study also found that the rates of overweight differed greatly between boys and girls, being more than twice as high among boys from high income families, compared with girls.
Obesity was higher among fathers of resident compared to migrant children at 41.5% and 36.9% respectively. The reverse was true for mothers, with 17.7% and 20.1% respectively.
Dr Weijia Liu, said: "At present, Childhood obesity is an important public health problem in China, Guangzhou. With the cooperation of University of Birmingham, UK, Guangzhou Center for disease control and prevention deepens the research of factors contributing to childhood obesity in China."
"Our research does not only provide scientific basis for formulating effective intervention for childhood obesity in the city, but also strengthens the friendship and cooperation between the two cities."