Is snoring a risk factor?

The ABZzzzs of snoring

Snorers sleep through their obnoxiously loud breathing, but other members of their household often do not. Their bed partner and family members may grow so tired of the noise that they insist the offender seek medical attention. Physiologic problems such as obesity, narrowing of the airway, or inadequate oropharyngeal muscle tone often can be identified as the cause of snoring. Whenever possible, the underlying disorder should be treated.

Is snoring a cause of vascular disease? An epidemiological review

Eight studies that examined the relation between snoring and vascular disease were identified. The prevalence of habitual snoring, measured by questionnaire or interview, varied from 3% to 29% of adults and was dependent on age, sex, obesity, and smoking habit. In men, habitual snoring was associated with hypertension and ischaemic heart disease, with adjusted relative risks in the range 1.3-2.0. For women, only one study provided adjusted estimates of relative risk, which were 2.8 for hypertension and 1.2 for angina. Adequately adjusted relative risks for cerebrovascular disease have not been reported, but unadjusted estimates varied from 1.6 to 10.3. These studies had several limitations, including the lack of a standard definition of snoring, the use of unvalidated questionnaires, and failure to account for confounding variables and the possibility of reporting bias. Only one study was prospective. Epidemiological criteria for a causal association between snoring and vascular disease have not been satisfied. The apparent excess risk is probably due to the consequences of sleep apnoea rather than snoring itself.

Determinants of blood pressure in snorers

To examine the hypothesis that the tendency to raised blood pressure in snorers is associated with nocturnal hypoxaemia and snoring, blood pressure was measured and snoring, oxyhaemoglobin saturation (SaO2), and thoraco-abdominal movements were monitored overnight in 372 snorers. Snoring was quantified as number of snores per hour of sleep (snoring index). The data were analysed by multiple linear regression of diastolic blood pressure against age, body mass index (BMI), apnoea-hypopnoea index (AHI, number of episodes per hour), snoring index, and SaO2. Diastolic blood pressure correlated significantly with BMI, AHI, and mean nocturnal oxygen saturation, but not with the snoring index. However, snoring index correlated with BMI, AHI, and mean nocturnal oxygen saturation. Snoring is thus not a direct risk factor for hypertension, but may influence blood pressure via its association with obesity, obstructive sleep apnoea, and nocturnal hypoxaemia.

Pharyngeal structure and function as a determinant of sleep-related breathing disorders: a unifying hypothesis

We propose a hypothesis which relates the pathogenesis of various sleep-related breathing disorders such as snoring, obstructive sleep apnea, and central sleep apnea to pharyngeal structure and function, i.e. pharyngeal area and compliance; these easily measured mechanical properties of the pharynx reflect the complex integrated response of upper airway muscles to changes in neural drive. Our arguments, although hypothetical, are based on the already existing measurements of pharyngeal dynamics in patients with sleep-related breathing disorders. If confirmed, this hypothesis would allow to predict a particular breathing disorder occurring during sleep from simple mechanical measurements performed in an awake subject, and furthermore it would help us to understand the effect of recent therapeutic modalities used in treatment of sleep apnea.

Snoring, nocturnal hypoxemia, and the effect of oxygen inhalation

Men who snore heavily have an increased incidence of hypertension, angina, stroke, and neuropsychologic dysfunction, which may be due to nocturnal oxygen desaturation. Nocturnal oxygen therapy might be beneficial to such individuals by improving oxygenation and relieving tissue hypoxia. Twenty-eight asymptomatic heavy snoring men were recruited for polysomnographic monitoring during sleep. During the first half-night, air was breathed through a nasal cannula, and during the latter half-night, 2 L/min oxygen was administered. Breathing air, 20 subjects demonstrated sleep apneas, hypopneas and nocturnal oxygen desaturation. Eighteen subjects had more than ten apneas plus hypopneas per hour. Thirteen subjects reached low oxygen saturation below 80 percent and eight below 70 percent. Only 13 of the 20 subjects showed improvement with oxygen therapy. Apneas alone were not decreased in frequency and were lengthened with oxygen therapy. Episodes of oxygen desaturation were improved by oxygen therapy and consequently, rates of hypopnea were decreased. Severe sleep apnea, hypopnea and oxygen desaturation are common in asymptomatic male snorers, and oxygen therapy is not always beneficial.

Reduction in snoring with phosphocholinamin, a long-acting tissue-lubricating agent

The efficacy of a long-acting lubricating and coating agent, phosphocholinamin, in reducing snoring was tested in 12 persons, six of whom received the agent as nose drops and six of whom received a placebo (tap water nose drops). In all subjects, the noise level was measured continuously by using a microphone taped near the cricothyroid notch. In the group treated with phosphocholinamin, the maximum nocturnal decibel level was reduced by a mean +/- SD of 13 +/- 3%, and the snoring index (defined as the number of snores per hour of sleep) was reduced by 25 +/- 12%. In the group treated with placebo, the maximum nocturnal decibel level increased 9 +/- 22% and the snoring index increased 1 +/- 20%. The differences between the two groups were statistically significant (P less than .05). It is concluded that phosphocholinamin can provide a useful medical alternative in the treatment of snoring and that further trials of this agent are indicated.

Snoring: clinical implications and treatment

Snoring has only recently come under wide study. Recent research has established the close relationship of severe snoring to sleep apnea in terms of the obstructive pathophysiology. Snoring tends to increase in severity over time and may progress to sleep apnea. Severe snoring may be associated with pulmonary and systemic hypertension, secondary polycythemia, and cardiac arrhythmias.

Snoring as a risk factor for disease: an epidemiological survey

In a study conducted in four family practice units in Toronto, Canada, 2001 subjects reported on snoring and medical conditions in members of their households. For spouses the prevalence of snoring increased with age up to the seventh decade, with a higher prevalence of nearly 85% in husbands. For 11 medical problems an association existed between snoring, its frequency, and the presence of the condition. This association continued when the data were corrected for sex, age, and marital state. For hypertension both men and women who snored between the fifth and 10th decades had a twofold increase over non-snorers. The prevalence of heart disease and other conditions, except for diabetes and asthma, also increased in snorers in this age group. When corrected for smoking and obesity the association between snoring, hypertension, and heart disease persisted. These findings extend those of Lugaresi et al, and if they could be confirmed snoring as a risk factor for conditions other than sleep apnoea and sleep disorders might be considered. Methods of alleviating the acoustic annoyance of snoring may also provide direct medical benefits.