Metabolic syndrome and non-alcoholic fatty liver disease:Asian definitions and Asian studies

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD), as conventionally recognized, is a metabolic disorder largely confined to residents of affluent industrialized Western countries. However, obesity and insulin resistance are not restricted to the West, as witnessed by their increasingly universal distribution. In particular, there has been an upsurge in metabolic syndrome in the Asia-Pacific region, although there are critical differences in the extent of adiposity between Eastern and Western populations. DATA SOURCES: An English-language literature search using PubMed (1999-2007) on obesity, metabolic syndrome and NAFLD, focusing on Asian definitions and Asian studies. RESULTS: NAFLD appears to be of long-standing insulin resistance and likely represents the hepatic manifestation of the metabolic syndrome. With insulin resistance as a common factor, the disease is associated with atherosclerosis and cardiovascular risk. All features of the metabolic syndrome and related events are assessed for practical management of NAFLD, although the criteria for the diagnosis of obesity and central obesity differ across racial groups. CONCLUSIONS: The increasing prevalence of obesity, coupled with diabetes, dyslipidemia, hypertension and ultimately metabolic syndrome, puts a very large population at risk of developing NAFLD in the coming decades. The simultaneous identification and appropriate treatment of the components of metabolic syndrome are crucial to reduce hepatic as well as cardiovascular morbidity and mortality.