16.12. Obstructive Sleep Apnea in Adults: Evolution, and Related Inflammation in Early Stages of Disease

Public examination of a doctoral dissertation in the field of Otorhinolaryngology

Doctoral candidate: Lic Med Johanna Sahlman

Time and venue: 16.12.2011 at 12 noon, Kuopio University Hospital, Auditorium 2

Language of the public examination: Finnish

Language of the dissertation: English

Obstructive sleep apnea (OSA) is a condition where there are repetitive breathing pauses due to upper airway obstruction during sleep. It decreases the patient’s quality of life by causing both night-time (e.g. snoring and restless sleep) and daytime symptoms (e.g. daytime sleepiness and impaired congnitive function). Based on the frequency of breathing pauses, OSA is divided into mild, moderate or severe disease. Thus far, the research has mainly been focused on more symptomatic subjects with moderate-to-severe OSA. In addition to immediate symptoms, these more severe forms of OSA have been observed to have an association with cardiovascular and cerebrovascular co-morbidities and impaired glucose metabolism. Obesity is considered as a major risk factor for all these conditions. Low-grade inflammation has been proposed to be one underlying mechanism which explains the increased risk of co-morbidities in patients with OSA. OSA, similar to many other chronic diseases, is a progressive disease. Even though mild OSA accounts for more than half of all OSA patients, there has been a lack of studies on the early stages of OSA or the evolution of the disease. Moreover, little is known about inflammation in mild OSA. Weight reduction is believed to have an impact on resolution of OSA and related metabolic disturbances. However, the effect of weight loss on the inflammation has not previously been studied in OSA patients.

This thesis includes a retrospective and a prospective clinical study. The aims of the retrospective study were to evaluate the objective outcome (sleep related respiratory events; N=50 patients) and subjective outcome (symptoms; N=81 patients) after different treatment options for mild OSA. The prospective trial assessed the impact of mild degree OSA on circulating inflammatory biomarkers in overweight or obese patients (N=84) compared with control patients (N=40), and whether weight loss results in changes in these markers (N=59).

This study shows that mild OSA, if left untreated, is a progressive disease both in terms of sleep related respiratory events and symptoms. Upper airway surgery for mild OSA in carefully selected patients seems to reduce the risk of disease progression. Low-grade inflammation seems to be activated already in the early stages of disease. In overweight patients weight reduction achieved by lifestyle intervention is an effective treatment for mild OSA, and it also results in improvement of inflammation. This study demonstrates that even mild OSA should be actively treated to prevent progression of the disease, and to reduce the risk for related co-morbidities.

The doctoral dissertation of Licentiate of Medicine, Specialist in Otorhinolaryngology Johanna Sahlman, entitled Obstructive Sleep Apnea in Adults: Evolution and Related Inflammation in Early Stages of Disease will be examined at the Faculty of Health Sciences. The opponent in the public examination will be Professor Olli Polo of the University of Tampere, and the custos will be Professor Juhani Nuutinen of the University of Eastern Finland.

Photo available for download at http://www.uef.fi/vaitoskuvat

For further information, please contact: Johanna Sahlman, johanna.sahlman@kuh.fi, tel. 040-7093743

Publishing year: 2011

Back to this years article listing