Obstructive sleep apnoea syndrome as a risk factor for hypertension: population study

Objective To assess whether sleep apnoea syndrome is an independent risk fa ctor for hypertension. Design Population study Setting Sleep clinic in Toronto, Participants 2677 adults, aged 20-85 years, referred to the sleep clinic wi th suspected sleep apnoea syndrome. Outcome measures Medical history, demographic data, morning and evening blo od pressure, and whole night polysomnography. Results Blood pressure and number of patients with hypertension increased l inearly with severity of sleep apnoea, as shown by the apnoea-hypopnoea ind ex. Multiple regression analysis of blood pressure levels of all patients n ot taking antihypertensives showed that apnoea was a significant predictor or both systolic and diastolic blood pressure after adjustment for age, bod y mass index, and sex. Multiple logistic I egression showed that each addit ional apnoeic event per hour of sleep increased the odds of hypertension by about 1%, whereas each 10% decrease in nocturnal oxygen saturation increas ed the odds by 13%. Conclusion Sleep apnoea syndrome is profoundly associated with hypertension independent of all relevant risk factors.