Childhood obesity on the rise in China

Childhood obesity is on the rise in China, and children and parents there tend to underestimate body weight, according to Penn State health policy researchers.

"Because many overweight Chinese children underestimate their weight, they are less likely to do anything to improve their diet or exercise patterns," said Nengliang Yao, graduate student in health policy and administration. "If they don't make changes, they are likely to be obese and have a lot of health problems in the future -- as we often see in the United States already."

Children between the ages of 6 and 18, living in nine different provinces in China, had their height and weight measured and body mass index (BMI) calculated as part of the 2006 China Health and Nutrition Survey (CHNS). The children and their mothers were separately asked to indicate whether they thought the child was underweight, normal weight or overweight.

The researchers looked at data from the CHNS for 176 overweight Chinese children and found that 69 percent of these children underestimated their own weight. Mothers were even more likely to underestimate the weight of their children, with 72 percent of the mothers rating their overweight children as normal or underweight, Yao reported in a recent issue of the World Journal of Pediatrics.

If a mother's BMI was lower, she was less likely to recognize her own child as overweight than a mother with a higher BMI. The researchers suggest that overweight mothers may have a better understanding of what "overweight" means from personal experience.

"Our study is more representative than previous studies because they have samples from only one province or maybe two cities," said Yao. "We have a better representation with nine provinces."

This research also is unusual because it includes measured height and weight, while much past research used self-reported height and weight. The researchers also used a larger population sample to gain a better understanding of how children's age, maternal education and place of residence affect weight and perceived weight.

They note that parental education and involvement is important in changing children's dietary and physical behaviors in the U.S., and recommend a similar approach for Chinese children. Public education campaigns can also help to raise awareness of the problem in China.

"I think the main message is that parents and kids often don't have an accurate perception of weight," said Marianne M. Hillemeier, associate professor of health policy and administration and demography. "In the U.S. some health care providers don't measure height and weight and compute BMI at regular well-child visits, so parents and children aren't always getting information from the doctors. Awareness is important no matter where you live."