Abdominal obesity and its metabolic complications: implications for the risk of ischaemic heart disease

Although the health hazards of obesity are well established, obese individuals are not all at equal risk of developing a disease, which reflects the heterogeneity of this condition. The regional distribution of body fat is now recognized as a very important component of the obesity-related health hazards. Epidemiological studies have shown that abdominal obesity, that is, a preponderance of fat in the abdominal area, is a better predictor of both cardiovascular disease and type 2 diabetes than obesity per se. It is now generally accepted that the fat located within the abdominal cavity, the visceral fat, is the best correlate of most of the highly atherogenic metabolic complications seen in individuals with abdominal obesity. These include, among others, insulin resistance and hyperinsulinaemia, hypertriglyceridaemia, reduced plasma high-density lipoprotein (HDL) cholesterol concentrations and an increased number of small, dense low-density lipoprotein (LDL) particles. This review summarizes the evidence that these metabolic complications may account to a large extent for the increased risk of cardiovascular disease associated with abdominal/visceral obesity. Abdominal obesity may be the most prevalent denominator of highly atherogenic dyslipidaemic and hyperinsulinaemic/insulin-resistant states in affluent, sedentary societies. Targeting individuals with this high-risk trait in primary prevention is therefore crucial if we are truly to have an impact on the incidence of cardiovascular disease.