Insulin resistance: an independent risk factor for cardiovascular disease?

Population-based studies have shown that patients with type 2 diabetes have a higher cardiovascular morbidity and mortality and an increased all-cause mortality compared with non-diabetic subjects. In non-diabetic subjects, hyperinsulinaemia not only has been associated with an increased cardiovascular risk, but is also related with a number of other cardiovascular risk factors--hyperglycaemia, hypertension, dyslipidaemia, and a central body fat distribution--that constitute the insulin resistance syndrome and are also characteristic of type 2 diabetes. After 23 years of follow-up in the Paris Prospective Study, both fasting and 2-h insulin concentrations were related with all-cause mortality in a U-shaped fashion, with low and high concentrations being associated with an increased risk, independently of other risk factors; in contrast, while high insulin levels carried an increased risk for cardiovascular and coronary heart disease mortality, this was not independent of other risk factors.