Evidence Linking Obstructive Sleep Apnea to Hypertension

Abstract

Obstructive sleep apnea (OSA) has been linked to hypertension in several experimental, epidemiological, and clinical studies. Animal modes of sleep apnea have provided strong evidence for a causal relationship with hypertension. Studies in humans have demonstrated that patients with sleep apnea have an increased blood pressure and a higher incidence of hypertension.  The most compelling evidence linking OSA and hypertension was provided by data from the Wisconsin Sleep Cohort Study. This study has demonstrated a dose-response association between sleep-disordered breathing at baseline and the presence of de novo hypertension 4 years later.  The odds ratios for the presence of hypertension at the 4-year follow-up study according to the apnea-hypopnea index (AHI) at base line were estimated after adjustment for baseline hypertension status, body mass index (BMI), neck and waist circumference, age, gender, and weekly use of alcohol and tobacco. Relative to the reference category of an AHI of 0 events per hour at baseline, the odds ratios for the presence of hypertension at follow-up were 1.42 (95% confidence intervals-CI 1.13-1.78) with an AHI of 0.1-4.9 events per hour at base line as compared with none, 2.03 (95% CI 1.29-3.17) with an AHI of 5.0-14.9 events per hour, and 2.89 (95% CI 1.46-5.64) with an AHI of 15.0 or more events per hour. These findings suggest two important concepts. First, sleep-disordered breathing is a risk factor for hypertension in the general population. Second, even sleep apnea that is considered mild may also contribute significantly to overall blood pressure levels...(excerpt)