title: Amount of weight loss or gain influences the severity of respiratory events in sleep apnea.
abstract: Severity of obstructive sleep apnea (OSA) is estimated based on respiratory events per hour [i.e., apnea-hypopnea index (AHI)]. The aim of this study was to investigate effects of weight change on the severity of respiratory events. Respiratory event severity, including duration and morphology, was estimated by determining parameters quantifying obstruction and desaturation event lengths and areas, respectively. Respiratory events of 54 OSA patients treated with dietary intervention were evaluated at baseline and after 5-year follow-up in subgroups with different levels of weight change. AHI, oxygen desaturation index (ODI) and obstruction event severities decreased during weight loss. In lower level weight loss, the decrease was milder in obstruction severity than in AHI and ODI, indicating that the decrease in the number of events is more focused on less severe events. In weight gain groups, parameters incorporating obstruction event severity, AHI and ODI increased, although increase was greater in parameters incorporating obstruction event severity. The number and severity of respiratory events were modulated differently by the level of weight change. AHI misses this change in the severity of respiratory events. Therefore, parameters incorporating information on the respiratory event severities may bring additional information on the health effects obtained with dietary treatment of OSA.
authors.affiliation: Department of Clinical Neurophysiology, Seinäjoki Central Hospital, Hanneksenrinne 6, 60220, Seinäjoki, Finland. antti.kulkas@epshp.fi.|Department of Applied Physics, University of Eastern Finland, Kuopio, Finland. antti.kulkas@epshp.fi.
authors.forename: A
authors.initials: A
authors.lastname: Kulkas
authors.affiliation: Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland.|Department of Applied Physics, University of Eastern Finland, Kuopio, Finland.
authors.forename: T
authors.initials: T
authors.lastname: Leppänen
authors.affiliation: Department of Otorhinolaryngology, Kuopio University Hospital, Kuopio, Finland.|Faculty of Health Sciences, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland.
authors.forename: J
authors.initials: J
authors.lastname: Sahlman
authors.affiliation: Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland.
authors.forename: P
authors.initials: P
authors.lastname: Tiihonen
authors.affiliation: Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland.|Faculty of Health Sciences, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland.
authors.forename: E
authors.initials: E
authors.lastname: Mervaala
authors.affiliation: Department of Respiratory Medicine, Kuopio University Hospital, Kuopio, Finland.
authors.forename: J
authors.initials: J
authors.lastname: Kokkarinen
authors.affiliation: Department of Respiratory Medicine, Kuopio University Hospital, Kuopio, Finland.
authors.forename: J
authors.initials: J
authors.lastname: Randell
authors.affiliation: Department of Otorhinolaryngology, Kuopio University Hospital, Kuopio, Finland.|Faculty of Health Sciences, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland.
authors.forename: J
authors.initials: J
authors.lastname: Seppä
authors.affiliation: Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland.|Department of Applied Physics, University of Eastern Finland, Kuopio, Finland.
authors.forename: J
authors.initials: J
authors.lastname: Töyräs
authors.affiliation: Oivauni Sleep Clinic, Kuopio, Finland.|Department of Clinical Nutrition, Institute of Public Health and Clinical Nutrition, University of Eastern Finland, Kuopio, Finland.
authors.forename: H
authors.initials: H
authors.lastname: Tuomilehto
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D017286:Polysomnography; D012891:Sleep Apnea Syndromes / Q000453:epidemiology* / Q000503:physiopathology*; D015430:Weight Gain / Q000502:physiology*; D015431:Weight Loss / Q000502:physiology*
chemical_list: D010100:Oxygen
keywords: Nocturnal respiratory events; Novel parameters; Obstruction severity; Sleep apnea; Weight gain; Weight loss