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

Objective To assess whether sleep apnoea syndrome is an independent risk factor for hypertension. Design Population study Setting Sleep clinic in Toronto, Participants 2677 adults, aged 20-85 years, referred to the sleep clinic with suspected sleep apnoea syndrome. Outcome measures Medical history, demographic data, morning and evening blood pressure, and whole night polysomnography. Results Blood pressure and number of patients with hypertension increased linearly with severity of sleep apnoea, as shown by the apnoea-hypopnoea index. Multiple regression analysis of blood pressure levels of all patients not taking antihypertensives showed that apnoea was a significant predictor or both systolic and diastolic blood pressure after adjustment for age, body mass index, and sex. Multiple logistic I egression showed that each additional apnoeic event per hour of sleep increased the odds of hypertension by about 1%, whereas each 10% decrease in nocturnal oxygen saturation increased the odds by 13%. Conclusion Sleep apnoea syndrome is profoundly associated with hypertension independent of all relevant risk factors.