Metabolic syndrome and sleep apnea.

Metabolic syndrome is a disorder characterized by abdominal obesity, hypertension, increased triglycerides, decreased HDL cholesterol and increased blood glucose. Accumulating evidence strongly indicates that insulin resistance and an increased amount of abdominal fat are the pathogenic factors for the characteristics of metabolic syndrome. The metabolic syndrome is characterized by an increased risk for the development of cardiovascular disease and type 2 diabetes mellitus. Studies indicate that sleep apnea may be a manifestation of the metabolic syndrome. It has also been suggested that the metabolic syndrome or "syndrome X" should also comprise obstructive sleep apnea and should then be called syndrome "Z". It appears that obstructive sleep apnea and the metabolic syndrome are characterized by the same pathophysiologic environment, which increases the risk for the development of cardiovascular disease. The increased amount of visceral fat and the accompanying insulin resistance seem to be the main characteristics responsible for the development of obstructive sleep apnea and the metabolic syndrome.