Comparison of the prevalence of obesity in adults among Hong Kong, mainland China and United States

Abstract

Obesity is a global health concern especially in the Western countries. It was reported that over 30% Chinese (age 20–59 years) were overweight, and about 7% Chinese were obese in the Peoples' Republic of China (PRC). However, Hong Kong (HK) was not included in this survey. Hong Kong perhaps is the most westernized city in PRC, the differences in the prevalence of overweight and obesity between HK and PRC is not known. The contrast of the prevalence with those reported for the US counterparts is worth investigating. PURPOSE: To compare the prevalence of overweight, general and central obesity between US, HK and PRC. METHODS: A total of 3,647 HK adults age 20–59 years-old participated in a citywide fitness survey in 2005–2006, which includes the measurements of body weight, height and waist circumference (WC). These measurements were compared with those retrieved from the PRC National Fitness Survey Report 2000 (n= 151,656) and the US NHANES 2004 data (n=2,840). The BMI cut-off point for overweight and obese Chinese was 24 and 28, respectively (Report of the Working Group on Obesity in China, 2002), while for American was 25 and 30, respectively (ACSM, 2005). The cut-off WC for Chinese men and women was 85 cm and 80 cm, respectively, whereas for US men and women was 102 cm and 88 cm, respectively. Differences in the prevalence of overweight, general and central obesity, by age groups and gender, were analyzed by Chi-square test. RESULTS: The prevalence of overweight individuals in US, PRC and HK was, respectively: for men: 68.27%, 39.55%, 35.08%; for women: 65.32%, 33.19%, 23.16%; the obesity for men: 30.18%, 7.65%, 5.95%; for women: 37.64%, 6.89%, 4.85%; the central obesity for men: 35.19%, 33.56%, 30.46%; for women: 63.68%, 29.76%, 23.25%. All comparisons were significant different at p<05. More than half and 1/3 of the US sample was overweight and obese respectively, which is much higher than the PRC and HK samples. HK sample demonstrated lower level of obesity and overweight than PRC. CONCLUSION: The prevalence of overweight and obesity in HK adults was lower than those in PRC and much lower than those in US. Reasons for the differences were not investigated in this study, but may possibly relate to the differences in lifestyle such as physical activity and diet. Difference in defining overweight and obesity may be another possible reason.