IS OBSTRUCTIVE SLEEP-APNEA A COMMON-CAUSE OF ESSENTIAL-HYPERTENSION

Obstructive sleep apnea (OSA) occurs in about 10% of the middle-aged p opulation but in about 30% of the hypertensive population of the same age. About 20% of the middle-aged population has hypertension but abou t 50% of patients with OSA have hypertension. Despite this close relat ionship between these two entities, previous attempts to determine whe ther the respiratory abnormalities in OSA were responsible for the hyp ertension were inconclusive, particularly because of the confounding e ffect of obesity which is common to both conditions. Data from recent observational and intervention studies, however, have succeeded in avo iding many of the pitfalls of earlier studies and it is now becoming e vident that OSA may be a major cause of hypertension - responsible for about 30% of all cases. Successful treatment of OSA by any means has been shown in most studies to cause significant reductions in blood pr essure throughout the 24 h period while at the same time alleviating t he vast array of symptoms and clinical abnormalities associated with t his common and serious condition. Despite the encouraging results of t hese recent data, more studies are urgently required which should incl ude larger numbers of patients and controls in order to clarify furthe r the relationship between OSA and hypertension.