Obesity as the key player in the metabolic syndrome

Abstract

Metabolic syndrome is a common cardiovascular risk factor in urbanized areas in China. In Hong Kong, it affects 17.1% of the population, increasing to 21.9% if the lower IOTF Asian cut-off values for central obesity were used. This is probably related to the increasing prevalence of excess adiposity. Epidemiological studies, cross-sectional and prospective, suggest that obesity plays a key role in metabolic syndrome in the Chinese, although other factors, such as genetic causes, may also enhance its development. Recent data, including those from Hong Kong and Taiwan, suggest that the adipocytokines, especially adiponectin, provide important links between obesity and various components of metabolic syndrome, through effects on insulin sensitivity, fatty acid synthesis and oxidation, nitric oxide production and inflammatory responses. Raised levels of C-reactive protein, a marker of low-grade chronic inflammation, are independently associated with obesity and predict the development of diabetes in the Chinese. Increased fat in the upper airway also predisposes to obstructive sleep apnea (OSA), sympathetic activation and insulin resistance, accounting for the high prevalence of “Syndrome Z” (metabolic syndrome plus obstructive sleep apnea). Appropriate weight control with regular physical exercise and a healthy diet is, therefore, the best prevention and treatment for metabolic syndrome.