Interaction between body weight obstructive sleep apnea (OSA) on C-reactive protein (CRP) in an otherwise healthy population: The EPIOSA study

Background: CRP is an inflammatory biomarker associated with atherosclerosis and cardiovascular disease (CVD). Obesity is an important OSA risk factor. To determine the independent roles of OSA and obesity in CVD is complicated by their coexistence. Aim: To assess association of OSA with CRP levels in a clinical cohort of otherwise healthy OSA patients and specifically to assess if it depends on body weight. Methods: Data from Epigenetics modifications in Obstructive Sleep Apnea (EPIOSA), a prospective clinical-based study on mechanisms of CVD damage in patients with OSA (ClinicalTrials.gov NCT02131610). CRP was measured in 183 subjects, 25-60 years old, who underwent sleep study. Smokers and participants with body mass index (BMI)u003e35 kg/m 2 or with any comorbid condition other than OSA were excluded. OSA classified according to apnea-hypopnea index (AHI). Results: Cohort of 183: 38 controls (AIH 2 ), multiple liner regression model with interaction terms showed independent association of AHI with CRP among those with BMI 2 and no interaction between AHI and BMI among patients with OSA and obesity (BMIu003e30 kg/m 2 ). Conclusions: In an otherwise healthy population, OSA severity is an independent predictor of levels CRP but interacts with obesity so that association is found only in non-obese patients. Supported by: ISCIII (PI12/01275), SEPAR (071/2012) and SADAR (02/2013).