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January 2010, Volume 60, Issue 1

Letter to the Editor

Obstructive sleep apnoea: awareness regarding risk factors

Dear Madam, obstructive sleep apnoea, a syndrome characterized by repetitive and periodic occlusion of the upper airway during sleep, affects around 2% of women and 4% of men3 globally but only a small number of cases in this group of adults have been diagnosed, and this is due to the lack of awareness of sleep apnoea amongst the physicians and the public at large.
The prevalence data of sleep apnoea from Pakistan is scarce due to lack of research in this aspect and hence common symptoms such as snoring, transient cessation of breathing and excessive daytime sleepiness are ignored by the common man and the physician and around 18% of the physicians tend to treat these symptoms with sedatives5 unaware of the risk factors and the clinical consequences of this syndrome.
Studies conducted over the years have shown a strong association between obesity and obstructive sleep apnoea. Certain cardiovascular abnormalities like hypertension, coronary artery disease, myocardial infarction, congestive heart failure and stroke are also associated with obstructive sleep apnoea.
Hypertrophy of the tonsils, disorders of the nose and nasal sinuses, joint problems of gout, arthrosis and gonarthrosis and osteoporosis also show an association with obstructive sleep apnoea.
It is well recognized that male sex also contributes as a particularly strong risk factor and confers a two to three -fold increased risk of sleep apnoea in men as compared to women.3 This increased difference is due to differences in fat deposition in men who have predominantly a central fat distribution around the neck, trunk and abdominal viscera compared to women. In addition to obesity and male sex the hormonal status particularly in females has an impact on sleep apnoea. Hence postmenopausal women are at a greater risk than the pre-menopausal ones. Apart from this women who are obese and have polycystic ovarian disease show a high prevalence of obstructive sleep apnoea due to increased serum androgen concentrations suggesting that male sex hormones promote the development of sleep apnoea.3
Recent studies demonstrating a racial predisposition to sleep apnoea in individuals of African American and Asian descent suggest that heritable factors also contribute towards increased risk of developing sleep apnoea.3
Therefore the general characteristics like male sex, age of more than 40, obesity, habitual snoring, daytime somnolence, nocturnal gasping and retrognathia and discrete airway abnormalities like tonsillar hypertrophy should always heighten the physician's suspicion of sleep apnoea and should not be neglected.
Given the global and local relevance to obstructive sleep apnoea, it is important to increase the awareness amongst not only the general population but more importantly amongst the physicians of developing countries like Pakistan about the common clinical features and the pertinent risk factors and complications of obstructive sleep apnoea syndrome.
Samrah Zaigham,1 Zarnad Zaigham2
4TH Year MBBS, Dow Medical College,1
Department of Medicine, Civil Hospital,2 Karachi, Pakistan.


1.Huang QR, Qin Z, Zhang S, Chow CM. Clinical patterns of obstructive sleep apnoea and its comorbid conditions: a data mining approach. J Clin Sleep Med 2008; 4: 543-50.
2.Browman CP, Sampson MG, Yolles SF, Gujavarty KS, Weiler SJ, Walsleben JA, et al. Obstructive Sleep Apnea and Body Weight. Chest 1984; 85: 435-8.
3.Schwartz AR, Patil SP, Laffan AM, Polotsky V, Schneider H, Smith PL. Obesity and Obstructive Sleep Apnoea: Pathogenic Mechanisms and Therapeutic Approaches. Proc Am Thorac Surg 2008; 5: 185-92.
4.Strollo PJ, Rogers RM. Obstructive Sleep Apnoea. N Eng J Med 1996; 334: 99-104.
5.Taj F, Aly Z, Kassi M, Ahmed M. Identifying people at high risk for developing sleep apnea syndrome (SAS): a cross-sectional study in a Pakistani population. BMC Neurology 2008; 8: 50.

Journal of the Pakistan Medical Association has agreed to receive and publish manuscripts in accordance with the principles of the following committees: