Sleep fragmentation as a risk factor for hypertension in middle-aged nonapneic snorers

Although a high prevalence of hypertension has been observed in snorers, whether there is a direct link between hypertension and snoring remains controversial. It has recently been demonstrated that an abnormal amount of breathing effort during snoring is responsible for sleep fragmentation even in the absence of sleep apnea syndrome criteria. We hypothesized that sleep fragmentation during snoring may be a direct risk factor for the development of hypertension. On the basis of polysomnographic data, 105 nonapneic patients between 40 and 65 years of age referred for snoring with social impairment were selected and categorized as snorers with (n=55) or without sleep fragmentation (n=50) based on whether the arousals index was 10 or greater or less than 10/h of sleep, respectively. Sleep distribution did not differ between the two groups, except for a longer duration of wake after sleep onset (58 +/- 43 min vs 42 +/- 38 min) and a shorter duration of slow-wave sleep in the group with sleep fragmentation (72 +/- 34 min vs 97 +/- 34 min). Although there were no statistically significant differences between the snorers with and without sleep disruption in terms of age (51.3 +/- 7.7 vs 48.6 +/- 6.0 years), body mass index (26.9 +/- 4.0 vs 27.2 +/- 5.5 kg/m2), sex ratio, respiratory indexes during sleep, daytime sleepiness, and daytime tiredness, prevalence of systemic hypertension was significantly higher in the sleep-fragmented group (20/55 vs 7/50). This significant difference persisted (16/51 vs 6/49) when patients using antihypertensive drugs with possible effects on the CNS were excluded. Our data suggest that sleep fragmentation is common in patients who seek medical help for snoring with social impairment and may play a role in the development of hypertension.