Sleep disorders in patients with CVD and diabetes: Association or causation?

Approximately 80% of cardiovascular disease (CVD) may be prevented by addressing traditional behavioral risk factors such as physical inactivity, poor diet, and tobacco smoking and by preventing or treating overweight, dyslipidemia and hypertension. Recent data indicate that sleep disturbances-in particular, short sleep duration, insomnia, and sleep apnea- may be novel, modifiable risk factors for CVD and diabetes, which if targeted appropriately may reduce CVD morbidity and mortality, with particular relevance to ethnic minorities who have a high prevalence of sleep disorders. Sleep disturbances likely increase cardio-metabolic risk via effects on diet and activity, as well as directly through effects on the hypothalamic-pituitary-adrenal axis, the autonomic nervous system, pro-inflammatory hormone release, glucose intolerance, and blood pressure. Experimental studies show that acute sleep deprivation and overnight hypoxemia each can trigger immediate surges in nocturnal blood pressure and alter mechanisms important in blood pressure control, endothelial function and atherosclerosis. Epidemiologic studies find that nightly sleep duration of under 6 hours is associated with a 20-50% increased odds of hypertension, stroke, and CVD mortality. A systemic review estimated that insomnia is associated with relative risks for CVD of 1.5 to 3.9. Sleep apnea has been shown to increase risk for hypertension,, coronary artery disease, heart failure, arrhythmias, and stroke. Treatment of sleep apnea is estimated to reduce blood pressure by an average of 3 mmHg and improve insulin resistance. Integration of sleep disorders screening and treatment in clinical practice may help reduce both CVD morbidity as well as improve quality of life associated with improved sleep.