Obesity and Its Related Diseases in China: The Impact of the Nut ...

The metabolic syndrome comprises a cluster of metabolic disorders, such as central obesity, insulin resistance, hyperinsulinemia, hyperglycemia, hypertension, hypertriglyceridemia and low high-density lipoprotein (HDL)-cholesterol (5).The syndrome is characterized by several metabolic disorders co-occurring in one individual (6–8), and it confers more risk for type 2 diabetes and cardiovascular disease than the sum of its parts (9–11). However, it is uncertain whether the metabolic syndrome actually exists as a united entity and points to a single underlying pathophysiology.

Previous studies have indicated that central obesity is the essential feature of the metabolic syndrome. Simple anthropometric indices like body mass index (BMI) and waist circumference are able to predict metabolic syndrome well. World Health Organization’s (WHO’s) definition of obesity as BMI ≤ 25 kg/m² has been globally used in clinical settings and epidemiological studies. However, increasing evidence has suggested that a single cutoff may not accurately describe disease risk in different populations and for different disease conditions. Compared with Caucasians, some Asian populations have a greater body fat at given BMI and stronger relationship of BMI with metabolic disorder (12). Based on these studies, the International Obesity Task Force recommended redefining overweight and obesity at a lower BMI and waist circumference cutoffs in Asian populations (12).

The China Nutrition Transition project was a community-based cross-sectional survey conducted in 2002–2003 to examine urban lifestyle’s impact on obesity and its related metabolic disorders. This project provided a good opportunity to assess the prevalence and characteristics of the metabolic syndrome in Chinese adults.