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Accurately perceiving one's own body weight is associated with positive weight-related behaviors, but in a recent study, nearly a third of Chinese Americans didn't perceive their weight correctly.

In the study, 32 out of 162 of the subjects underestimated their body weight, and 20 overestimated it. Accuracy of perception of body weight significantly predicted waist circumference, hip circumference, height ratio, body mass index (BMI), and weight, all at P<0.001.

In addition, there were three significant factors that affected perception: gender (P=0.003), age (P=0.003), and years of education (P=0.047), found the researchers, who published their findings in Obesity Research & Clinical Practice on May 27.

"The study could lay a good foundation for future possible intervention studies for obesity management in the minority group of Chinese Americans," wrote author Mei Fu, RN, PhD, at the college of nursing at New York University, and colleagues.

Men were more likely than women to underestimate their weight in the study, meaning they perceived their body weight as being lighter than their actual weight (odds ratio 2.34, 95% CI 1.01-5.43). On the other hand, women were more likely to overestimate their own weight (OR 3.59, 95% CI 1.13-11.42).

"The finding of this study suggests that obesity research studies for Chinese Americans should pay attention to gender difference," wrote the authors.

Those in the overestimation group were also significantly younger than the group that was accurate and the group that underestimated, by 13 years (93% CI 4.07-23.27). In addition, they had 3.2 fewer years of education than those in the overestimation group (95% CI 0.11-6.21).

Chinese Americans, who make up 4% of the population in the U.S., face a far greater risk of obesity than do their counterparts in China, because of immigration and environmental factors, according to the authors.

Fu and colleagues recruited participants in 2012 and gathered demographic data. All of the participants were adults who self-identified as Chinese American, and they were evaluated at a community health center in New York City.

Participants were asked to rate themselves as being under, over, or normal weight. They were then measured and placed into a category using BMI. Information on fasting plasma glucose and HbA1C, as well as on hypertension, diabetes, and heart disease, was gathered.

The average BMI of the participants was 24.3. An analysis showed that those who accurately estimated their weight had a 6.63 cm larger waist circumference (95% CI 0.88-12.38, P=0.019) and 5.54 cm larger hip circumference (95% CI 0.26-10.63, P=0.037) than the overestimation group.

Fu and colleagues wrote that their findings should lead to more research that can help clinicians design interventions that are specific to age and gender. Obesity tends to be a problem among older Chinese-Americans, for example, where a recent study showed that of 125 of them aged 50-98, two-thirds were overweight or obese.

"The association of age and perception of body weight in our study suggested that the elderly Chinese Americans, the majority of whom were in the consistent estimation and underestimation group in our study, may need more targeted intervention to lose weight," wrote Fu and co-authors.

Limitations of the study included its small size and reduced power. In addition, the researchers did not examine whether patients were actively trying to lose weight during the study, which has been shown to be related to accuracy of body weight perception.