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Ahmed Elmasry


Comprehensive Summaries of Uppsala Dissertations from the Faculty of Medicine 970
Distributor: Uppsala University Library, Box 510, SE- 751 20 Uppsala, Sweden


Sleep Disordered Breathing

Natural Evolution and Metabolism

Dissertation in Respiratory Medicine to be Publicly examined in the lecture hall, University Hospital, Entrance 50 ground floor, on November 20, 2000, at 9.15 a.m., for the Degree of Doctor of Philosophy (Faculty of Medicine). The examination will be conducted in English.


Elmasry, A. 2000. Sleep disordered breathing. Natural evolution and metabolism. Acta Universitatis Upsaliensis. Comprehensive Summaries of Uppsala Dissertations from the Faculty of Medicine 970. 66 pp. Uppsala. ISBN 91-554-4848-8.

Sleep disordered breathing is manifested by snoring and repeated episodes of apneas and hypopneas. The induced hypoxia and sleep fragmentation are thought to be responsible for many metabolic disturbances.

In 1984, 3,201 men aged 30 to 69 answered a questionnaire on snoring, sleep disorders and somatic diseases. In 1994, 2,668 of the survivors (89.7%) again answered similar questionnaire. Among habitual snorers in 1984, 5.4% had developed diabetes during the 10-yr period compared with 2.4% of those without habitual snoring (p<0.001). The risk of developing diabetes was higher in obese snorers (OR 7.0, 95%CI 2.9-16.9) than in obese non-snorers (5.1 (2.7-9.5)).

In 1994, 392 men reported hypertension, of whom a sample of 116 men was investigated using a whole night sleep study, a fasting blood sample and an overnight urine collection. The prevalence of severe obstructive sleep apnea (OSA), defined as apnea-hypopnea index (AHI) = 20/h was higher in diabetic hypertensives compared to normoglycemic hypertensives (36.0 vs 14.5%, p<0.05). The risk of having diabetes was higher in men with OSA and central obesity (OR 11.8, 95%CI 2.0-69.8) than in men with central obesity only (3.6 (0.9-14.8)).

Hypertensive men with OSA, defined as AHI = 10/h had higher concentrations of urinary normetadrenaline (p<0.001) and metadrenaline (p<0.05) in comparison with subjects without OSA. There was a linear association between measurements of OSA, such as AHI, and concentrations of normetadrenaline and metadrenaline.

In 1985, a sample of 61 men with snoring and daytime sleepiness were investigated using polysomnography. In 1995, 38 men of them (70% of the survivors) were reinvestigated. During the 10-yr period, nine men had been treated for OSA. Of the 29 untreated subjects, the number of cases of OSA, defined as AHI = 5/h increased from 4 in 1985 to 13 in 1995 (p<0.01). This progress of OSA was associated with worsening of reported daytime sleepiness.

In conclusion, although obesity is the main risk for high prevalence and incidence of diabetes in men, sleep disordered breathing may add to this risk. Sleep disordered breathing is associated with increased urinary catecholamines suggesting an increased sympathoadrenal activity which may explain the increased cardiovascular morbidity in OSA. Sleep disordered breathing is a progressive disorder.

Key words: Snoring, sleep apnea, epidemiology, obesity, diabetes, catecholamines, hypertension, evolution, population-based, prospective.

Ahmed Elmasry, Department of Medical Sciences, Respiratory Medicine and Allergology, Uppsala University, Akademiska sjukhuset, SE-751 85 Uppsala, Sweden

This thesis is based on the papers listed below, which will be referred in the following text by the Roman numerals I-IV.

I Elmasry A, Janson C, Lindberg E, Gislason T, Tageldin MA, Boman G. The role of habitual snoring and obesity in the development of diabetes: A 10- year follow-up study in a male population.

J Intern Med 2000; 248: 13-20

II Elmasry A, Lindberg E, Berne C, Janson C, Gislason T, Tageldin MA, Boman G. Sleep disordered breathing and glucose metabolism in hypertensive men: A population based study.


III Elmasry A, Lindberg E, Hedner J, Janson C, Boman G. Obstructive sleep apnea and urine catecholamines in hypertensive men: A population based study.


IV Lindberg E, Elmasry A, Gislason T, Janson C, Bengtsson H, Hetta J, Nettelbladt M, Boman G. Evolution of sleep apnea syndrome in sleepy snorers: a population-based prospective study.

Am J Respir Crit Care Med 1999; 159: 2024-2027

Reprints have been made with the permission of the publisher.

This work was supported by grants from the Swedish Heart Lung Foundation, the Swedish Medical Research Council, the Uppsala Association against Heart and Lung Disease and the Josef and Linnéa Carlsson Memorial Fund.

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