New insights into the growing diabetes epidemic in China: middle-aged obesity-related insulin resistance becomes the major threat

Delineation of the relationship between insulin resistance, β cell dysfunction, and obesity is crucial for the prevention and effective management of diabetes. Previous studies have indicated that, compared with type 2 diabetes in Caucasian, type 2 diabetes in East Asians is characterized primarily by β cell dysfunction rather than insulin resistance. This pathophysiological characterization of diabetes in East Asians is mainly derived from Japanese and Asian-American populations, whereas data from mainland China are scarce. Over the past four decades, China has witnessed a substantial rise in obesity, in parallel with the transitions from principally active lifestyles and calorie-restricted diets to sedentary life styles and energy-dense, western diets. Obesity is an insulin resistance state and the major factor driving the worldwide epidemic of diabetes. It is unknown whether, and if so how, obesity affects the two primary mechanisms, insulin resistance and β cell dysfunction, responsible for the development of diabetes in the Chinese population. Recently, the Lancet Diabetes & Endocrinology published an original research paper from the China Cardiometabolic Disease and Cancer Cohort Study (4C). From a public health perspective, the results of this study reinforce the urgency of tackling obesity as a major preventive strategy for the epidemic of type 2 diabetes in China. Key words: Diabetes mellitus; Insulin resistance; βcell dysfunction; Obesity; China