The interaction of obstructive sleep apnea and obesity on the inflammatory markers C-reactive protein and interleukin-6: the Icelandic Sleep Apnea Cohort.

• Published in: SLEEP
• Main Authors: Arnardottir, Erna S, Maislin, Greg, Schwab, Richard J, Staley, Bethany, Benediktsdottir, Bryndis, Olafsson, Isleifur, Juliusson, Sigurdur, Romer, Micah, Gislason, Thorarinn, Pack, Allan I
• Other Authors: Department of Respiratory Medicine and Sleep, Landspitali-The National University Hospital of Iceland, Reykjavik, Iceland.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2012
• Subjects: Abdominal Fat; Biological Markers; Body Mass Index; C-Reactive Protein; Cross-Sectional Studies; Female; Humans; Interleukin-6; Intra-Abdominal Fat; Male; Middle Aged; Obesity; Sleep Apnea; Obstructive; Iceland
• Online Access: http://hdl.handle.net/2336/253294; https://doi.org/10.5665/sleep.1952

To access publisher full text version of this article. Please click on the hyperlink in Additional Links field. STUDY OBJECTIVES: To assess the relative roles and interaction of obstructive sleep apnea (OSA) severity and obesity on interleukin-6 (IL-6) and C-reactive protein (CRP) levels. DESIGN: Cross-sectional cohort. SETTING: The Icelandic Sleep Apnea Cohort. PARTICIPANTS: 454 untreated OSA patients (380 males and 74 females), mean ± standard deviation age 54.4 ± 10.6 yr. MEASUREMENTS AND RESULTS: Participants underwent a sleep study, abdominal magnetic resonance imaging to measure total abdominal and visceral fat volume, and had fasting morning IL-6 and CRP levels measured in serum. A significantly higher correlation was found for BMI than visceral fat volume with CRP and IL-6 levels. Oxygen desaturation index, hypoxia time, and minimum oxygen saturation (SaO₂) significantly correlated with IL-6 and CRP levels, but apnea-hypopnea index did not. When stratified by body mass index (BMI) category, OSA severity was associated with IL-6 levels in obese participants only (BMI > 30 kg/m²). A multiple linear regression model with interaction terms showed an independent association of OSA severity with IL-6 levels and an interaction between OSA severity and BMI, i.e., degree of obesity altered the relationship between OSA and IL-6 levels. An independent association of OSA severity with CRP levels was found for minimum SaO₂ only. A similar interaction of OSA severity and BMI on CRP levels was found for males and postmenopausal women. CONCLUSIONS: OSA severity is an independent predictor of levels of IL-6 and CRP but interacts with obesity such that this association is found only in obese patients. NIH HL072067 HL094307 University of Iceland Landspitali University Hospital