Is Snoring a Risk Factor?

CHEST VOLUME 80 I NUMBER 5/ NOVEMBER, 1981

EDITORIALS

apnea and nocturnal oxygen desaturation are disturbingly reminiscent of the factors associated with shortened Jongevity.22•25 Although obesity may be a risk factor because of associated conditions such as diabetes, hypercholesterolemia, and hypertension, it is nevertheless strongly correlated with reduced longevity, particularly among the very obese.26 Excellent statistical evidence is available to relate male sex, menopause, older age, excess alcohol, and sleeping pill ingestion to reduced life span.20•22 -25 Until recently, no thought has been given to the possibility that these factors may reduce longevity by a common mechanism-ie, the predisposition to snoring, sleep-disordered breathing, and nocturnal hypoxia. In fact, studies of asymptomatic subjects have shown few episodes of severe nocturnal oxygen desaturation, and then only in occasional subjects; and no nocturnal arrhythmias were observed. 14 Nevertheless, although the subjects were monitored for only one or two nights, in each study several of them had a few episodes of profound oxygen desaturation and apnea usuaiJy associated with snoring.14 ,16, t 7 Presumably, such phenomena also occur every night at home and are exacerbated by ethanol ingestion. Throughout a lifetime, ample opportunity exists for occasional arrhythmia or other cardiovascular events induced by nocturnal hypoxia. Perhaps the predisposition to snoring and the consequent sleep-disordered breathing and oxygen desaturation have been neglected too long in considering the important risk factors for mortality. A. lay Block, M.D., F.C.C.P. Gainesville, Florida

Is Snoring a Risk Factor? The pickwickian syndrome is characterized by obesity, daytime hypersomnolence, and alveolar hypoventilation causing hypercapnia and hypoxemia. Common consequences of the syndrome include secondary polycythemia and heart failure. 1,2 Authors have caiied attention to the propensity of such patients to die suddenly, often during sleep.3·4 The explanation for the high nocturnal mortality in this syndrome is now clear and relates to severe obstructive sleep apnea and nocturnal oxygen desaturation. When respiration is monitored during sleep, patients with the pickwickian syndrome show hundreds of episodes of severe oxygen desaturation accompanied by episodic pulmonary hypertension, severe bradycardia, and multiple cardiac arrhythmias.5.s Bypass of the pharynx by tracheostomy relieves the obstructive sleep apnea and nocturnal oxygen desaturation and eliminates the cardiovascular consequences. 11-n In addition to the relationship between nocturnal events and early death in pickwickian patients, the evidence for such a relationship may also extend to the general population. Recent studies have clearly shown that asymptomatic, obese, severe snorers may also have nocturnal apnea, oxygen desaturation, increased carbon dioxide tension, and nocturnal pulmonary and systemic hypertension. 12•15 In several studies of asymptomatic subjects, we have shown that sleep apnea, hypopnea, and nocturnal oxygen desaturation correlate positively with the male sex, female menopause, older age, excess weight, and alcohol ingestion. 14"19 Those subjects with sleep-disordered breathing and nocturnal oxygen desaturation were also noted to snore. Kripke et a] 20 have also reported that use of sleeping pills may double the death rate in the elderly. In addition, Smolensky21 has studied 432,000 reported deaths with reference to chronobiology and reports that the most frequent time of death is between 5:00 and 6:00 AM. The factors that correlate positively with sleep

Dep~r~ent of Medicine, University of Florida College of Medtcme, and the Veterans Administration Medical Center. Supported by funds from the Medical Research Service of the Veterans Administration and by grant HL-22622-03 from the U.S. Public Health Service. Reprint requests: Dr. Block, Pulmonary Medicine, ]. Hillis M1Uer Health Center, University of Florida, Gainesville

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REFERENCES

1 Burwell CS, Robin ED, Whaley RD, Bickelman AG. Extreme obesity associated with alveolar hypoventilation: a pickwickian syndrome. Am J Med 1956; 21 :811-18

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2 Rochester DF, Enson Y. Current concepts in the pathogenesis of the obesity-hypoventilation syndrome. Am J Med 1974; 57:402-20 3 MacGregor Ml, Block AJ, Ball WC Jr. Serious complications and sudden death in the pickwicltian syndrome. Johns Hopkins Med J 1970; 126:279-95 4 Miller A, Granada M. In-hospital mortality in the pickwickian syndrome. Am J Med 1974; 56:144-50 5 Walsh RE, Michaelson ED, Harkleroad LE, Zighleboim A, Sackner MA. Upper airway obstruction in obese patients with sleep disturbance and somnolence. Ann Intern Med 1972; 76:185-92 6 Sackner MA, Landa L, Forrest T, Greeneltch D. Periodic sleep apnea: chronic sleep deprivation related to intermittent upper airway obstruction and central nervous system disturbance. Chest 1975; 67:164-71 1 GuiDeminault C, Tilkian A, Dement WC. The sleep apnea syndromes. Ann Rev Med 1976; 27:465-84 8 Guilleminault C, Eldridge FL, Tilkian AG, Simmons FB, Dement WC. Sleep apnea syndrome due to upper airway obstruction. A review of 25 cases. Arch Intern Med 1977; 137:296-300 9 Tilkian AG, Guilleminault C, Schroeder JS, Lehrman KL, Simmons FB, Dement WC. Sleep-induced apnea syndrome. Prevalence of cardiac arrhythmias and their reversal after tracheostomy. Am J Med 1977; 63:348-58 10 Tilkian AG, Guilleminault C, Schroeder JS, Lehrman KL, Simmons FB, Dement WC. Hemodynamics in sleepinduced apnea. Studies during wakefulness and sleep. Ann Intern Med 1976; 85:714-19 11 Motta J, Gilleminault C, Schroeder JS, Dement WC. Tracheostomy and hemodynamic changes in sleep-induced apnea. Ann Intern Med 1978; 89:454-58 12 Lugaresi E, Coccagna G, Fameti P, Montovani M, Cirignotta F. Snoring. Electroencephalogr Clin Neurophysiol 1975; 39:59-64 13 Lugaresi E, Coccagna G, Cirignotta F. Snoring and its clinical implications. In: Sleep apnea syndromes. Guilleminault C, Dement WC, eds. New York: Alan R. Liss, 1978:13-21 14 Block AJ, Boysen PG, Wynne JW, Hunt LA. Sleep apnea, hypopnea, and oxygen desaturation in normal subjects. A strong male predominance. N Engl J Med 1979; 300:513-17 15 Harman E, Wynne JW, Block AJ, Malloy-Fisher L. Sleep-disordered breathing and oxygen desaturation in obese patients. Chest 1981; 79:256-60 16 Block AJ, Wynne JW, Boysen PG. Sleep-disordered breathing and noctumal oxygen desaturation in postmenopausal women. Am J Med 1980; 69:75-79 17 Block AJ, Wynne JW, Boysen PG, Lindsey S, Martin C, Cantor B. Menopause, medroxyprogesterone and breathing during sleep. Am J Med 1981; 1:506-10 18 Taasan VC, Block AJ, Boysen PG, Wynne JW. Alcohol increases sleep apnea and oxygen desaturation in asymptomatic males (abstract). Am Rev Respir Dis 1981; 123:64 19 Taasan VC, Block AJ, Boysen PG, Wynne JW. Alcohol increases sleep apnea and oxygen desaturation in asymptomatic men. Am J Med (in press) 20 Kripke DF, Simmons RN, Gar&nkel L, Hammand C. Short and long sleep and sleeping pills. Is increased mortality associated? Arch Gen Psychiatry 1979; 36:10316 21 Smolensky M, Halbreg F, Sargent F II. Chronobiology

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of the life sequence. In: Advances in climatic physiology. ltoh S, Ogata K, Yoshimura H, eds. New York: SpringerVerlag, 1972:281-318 Singer RB, Levinson L. Medical risks: patterns of mortality and survival. Lexington, Mass: Lexington Books, 1976 Society of Actuaries, Association of Life Insurance Medical Directors of America. Build study. March 1980, U.S.A. U.S. Department of Health and Human Services. Vital Statistics of the United States. Life Tables, Vol II, Section V. Publication No. 81-1104. Washington, D.C.: Public Health Service, 1978 Sorlie P, Gordon T, Kannel WB. Body build and mortality. The Framingham study. JAMA 1980; 243:1828-31 Drenick EJ, Bale GS, Seltzer F, Johnson DG. Excessive mortality and causes of death in morbidly obese men. JAMA 1980; 243-443-45

The Lung and the Liver Hepatic cirrhosis is associated with a wide variety of circulatory abnormalities. In the kidney, in severely decompenated cirrhosis, there may be renal cortical hypoperfusion leading to renal insufficiency of the hepatorenal syndrome. Cirrhotic patients commonly have increased cardiac output, decreased peripheral resistance, and expanded blood volume associated with hypoxemia and hypocapnia. Still other investigators have demonstrated increased pulmonary blood flow with decreased pulmonary artery pressure and resistance in patients with chronic liver disease. Paradoxically, an increasing number of cirrhotic patients have also been discovered to have idiopathic pulmonary hypertension. Tense ascites, hydrothorax, anemia, and fever are other obvious factors that may alter the circulation in cirrhotic patients. Daoud and associates demonstrated the consistent loss of the hypoxic pulmonary vasoconstricting mechanism in ten severely decompensated cirrhotic subjects selected because they had clinical evidence of hyperdynamic systemic circulation. They postulated that impaired hypoxic vasoconstriction could lead to a relatively dilated pulmonary microvascular bed and a mismatch of ventilation and perfusion with resultant hypoxemia. In this issue (see page 510) Naeije et al have reported valuable additional hemodynamic observations in cirrhotic patients. They showed that the loss of hypoxic pulmonary vasoconstriction ("nonresponders") in cirrhotic subjects is by no means uniform occurring in only seven of their 24 patients breathing 12.5 percent inspired oxygen for ten minutes. The other 17 "responders" increased pulmonary vascular resistance by greater than 20 percent over baseline. In both "responders.. and "nonresponders,• CHEST, 80: 5, NOVEMBER, 1981