Published online before print March 23, 2006, doi: 10.1161/01.STR.0000217465.88193.c3
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(Stroke. 2006;37:1150.)
© 2006 American Heart Association, Inc.
Letters to the Editor |
Obstructive Sleep Apnea as an Independent Risk Factor for Stroke and Mortality
Department of Cardiology, Complejo Hospitalario de Jaén, Jaén, Spain
Department of Neumology, Hospital Universitario Son Dureta, Palma de Mallorca, Spain
Department of Neumology, Hospital Universitario La Paz, Madrid, Spain
To the Editor:
In a recent article by Hu et al,1 the authors stated that both hypertension and type 2 diabetes were independently associated with an increased risk for stroke and stroke mortality. Indeed, the association of hypertension and type 2 diabetes conferred the highest risk, being higher than that attributable to each disorder separately.
We would like to remark on the possible role of obstructive sleep apnea (OSA) as one other possible factor contributing to the incidence of stroke and stroke-related mortality in their study population. OSA is characterized by intermittent episodes of partial or complete obstruction of the upper airway during sleep that disrupts normal ventilation and sleep architecture and is typically associated with snoring and daytime sleepiness. This primary sleep disorder affects 17% to 24% of North American adults,2 and is associated with a group of proinflammatory and prothrombotic factors that have been identified to be important in the development of atherosclerosis.3 On the other hand, OSA is now recognized as an important identifiable cause of systemic hypertension,4 and in patients with established type 2 diabetes, a significant relationship between OSA and fasting insulin, glucose, and hemoglobin A1c levels, that is independent of obesity, has been reported.5 A strong association between OSA and the risk of stroke or death has been established, and that association is independent of a broad range of other cardiovascular risk factors.6,7 In view of the aforementioned data it is conceivable that part of the risk of stroke assumed to be attributable to hypertension or type 2 diabetes might be attributable to the presence of unevaluated OSA.
References
1. Hu G, Sarti C, Jousilahti P, Peltonen M, Qiao Q, Antikainen R, Tuomilehto J. The impact of history of hypertension and type 2 diabetes at baseline on the incidence of stroke and stroke mortality. Stroke. 2005; 36: 2538–2543.
2. Young T, Peppard PE, Gottlieb DJ. Epidemiology of obstructive sleep apnea: a population health perspective. Am J Respir Crit Care Med. 2002; 165: 1217–1239.
3. Shamsuzzaman AS, Gersh BJ, Somers VK. Obstructive sleep apnea: implications for cardiac and vascular disease. JAMA. 2003; 290: 1906–1914.
4. Chobanian AV, Bakris GL, Black HR, Cushman WC, Green LA, Izzo JL Jr, Jones DW, Materson BJ, Oparil S, Wright JT Jr, Roccella EJ. Seventh report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. Hypertension. 2003; 42: 1206–1252.
5. Elmasry A, Lindberg E, Berne C, Janson C, Gislason T, Awad TM, Boman G. Sleep-disordered breathing and glucose metabolism in hypertensive men: a population-based study. J Intern Med. 2001; 249: 153–161.[CrossRef][Medline] [Order article via Infotrieve]
6. Yaggi HK, Concato J, Kernan WN, Lichtman JH, Brass LM, Mohsenin V. Obstructive sleep apnea as a risk factor for stroke and death. N Engl J Med. 2005; 353: 2034–2041.
7. Arzt M, Young T, Finn L, Skatrud JB, Bradley TD. Association of Sleep-disordered Breathing and the Occurrence of Stroke. Am J Respir Crit Care Med. 2005; 172: 1447–1451.
Department of Epidemiology and Health Promotion, National Public Health Institute, Helsinki, Finland, Department of Public Health, University of Helsinki, Helsinki, Finland
Response:
We appreciate Arias et al for their comments on the potential role of obstructive sleep apnea (OSA) as another possible factor contributing to the incidence of stroke and stroke-related mortality in our results.1 We agree with their comments that OSA is an important health problem and seems to be an independent risk factor for the development of hypertension,2 and may increase the risk of stroke or death from any cause.3,4 Unfortunately, attributable to a very large sample size, we were not able to collect information about the diagnosis of OSA at baseline or during the follow-up. However, the role of OSA and other sleep disorders in the development of diabetes and cardiovascular diseases is an interesting question with a potential public health importance and needs to be considered in future studies.
References
1. Hu G, Sarti C, Jousilahti P, Peltonen M, Qiao Q, Antikainen R, Tuomilehto J. The impact of history of hypertension and type 2 diabetes at baseline on the incidence of stroke and stroke mortality. Stroke. 2005; 36: 2538–2543.
2. Chobanian AV, Bakris GL, Black HR, Cushman WC, Green LA, Izzo JL Jr, Jones DW, Materson BJ, Oparil S, Wright JT Jr, Roccella EJ; National Heart, Lung, and Blood Institute Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure; National High Blood Pressure Education Program Coordinating Committee. The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure: the JNC 7 report. JAMA. 2003; 289: 2560–2572.
3. Marin JM, Carrizo SJ, Vicente E, Agusti AG. Long-term cardiovascular outcomes in men with obstructive sleep apnoea-hypopnoea with or without treatment with continuous positive airway pressure: an observational study. Lancet. 2005; 365: 1046–1053.[Medline] [Order article via Infotrieve]
4. Yaggi HK, Concato J, Kernan WN, Lichtman JH, Brass LM, Mohsenin V. Obstructive sleep apnea as a risk factor for stroke and death. N Engl J Med. 2005; 353: 2034–2041.
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