China's 'diabetes epidemic' debunked

A study that appeared to show that China is experiencing a rapid rise in diabetes has been debunked by critics who say the apparent increase in diabetes was caused by the researchers measuring a different variable.
In September Dr Xu Yu of the Shanghai Jiaotong University School of Medicine published  a study in JAMA which showed that the prevalence of diabetes had increased to 12% of adults Chinese. The prevalence of 'pre-diabetes' was said to be at 50%. However in a letter published in JAMA this week Dr Kristine Faerch of the Steno Diabetes Center, Denmark, says the alarming figures published Dr Xu are a false alarm caused by the measurement of different parameters, not a true change in the rates of diabetes.
Dr Faerch says the rates of diabetes were increased by adding the HbA_1c criterion to the diagnosis of diabetes and using the lower diagnostic threshold for impaired fasting glucose of 100 mg/dL instead of 110 mg/dL.
When more conventional methods of measuring diabetes are used, the rates of diabetes are unchanged from the last study done two years ago, at around 9.7%, she notes. Also the rates of pre-diabetes will be 15% rather than the 50% suggested by Dr Xu's study, she adds.
Another letter in JAMA says Dr Xu's study would also overestimate levels of diabetes because it ignored non-residents of cities such as migrant workers, college students, and military personnel who would likely have lower levels of diabetes.