FRACTION OF EXHALED NITRIC OXIDE (FENO) IN METABOLIC SYNDROME

Abstract

SESSION TITLE: Systemic Disease and the Lung 1 SESSION TYPE: Original Investigations PRESENTED ON: 10/07/2018 01:00 PM - 02:00 PM PURPOSE: Metabolic syndrome (MetS) is a pro-inflammatory status that affects different body systems including the pulmonary system. Many studies showed an association between MetS and abnormal pulmonary function. Knowing that FENO has been proven as a marker for eosinophilic airway inflammation, the aim of this study is to compare FENO levels in individuals with MetS, with the rest of the population to know whether they have higher degree of eosinophilic airway inflammation. Since MetS is associated with obesity, and as obesity is associated with abnormal pulmonary function, we studied three groups: MetS, obese without MetS, and non-obese without MetS. METHODS: This is a cross-sectional analysis using the National Health and Nutrition Examination Surveys (NHANES lll) collected from 2007 to 2012. We included 3,871 adult participants with the following variables: age, gender, ethnicity, smoking status, MetS components, asthma status, body mass index (BMI), and FENO. We identified three groups: non-obese without MetS, obese without MetS (obese group), and MetS group (regardless of the BMI). MetS was defined using the current Adult Treatment Panel III criteria. Obesity was defined as having BMI ≥ 30 kg/m2. We compared FENO means by group using analysis of variance. Multiple variable linear regression was used to adjust for age, gender, ethnicity, smoking status, and asthma status. RESULTS: The MetS group had the highest FENO mean, followed by the obese group, and then the non-obese without MetS group (15.64 parts per billion [ppb], 14.01 ppb, and 13.44 ppb, respectively; p=0.003). Crude analysis was followed by adjustments for age, gender, smoking status, and asthma status. Interestingly, the association stayed significant after adjusting for all the above-mentioned factors except age (p=0.002). When age was included, the association was attenuated (p=0.09). Inclusion of an interaction term between age and group revealed a differential association for FENO and age by group (p =0.048). Stratification for age was performed using the sample median age of 45-years as a cutoff. In ≥ 45-year-old participants, the association between FENO and group was non-significant (p=0.645). In < 45-year-old participants, there was a trend, but not an association, between FENO and group (p = 0.08). CONCLUSIONS: MetS participants had the highest FENO mean, and therefore the highest degree of eosinophilic airway inflammation. However, their mean is considered within low FENO range ( < 25 ppb) and therefore of unclear clinical significance. Age attenuated the association with FENO, especially in the ≥ 45-year-old participants. This is important in supporting the association between age and FENO in adults as there was less agreement on this association in the previous studies. CLINICAL IMPLICATIONS: Though the association between MetS and FENO is statistically significant, its clinical significance is unclear and warrants more studies. DISCLOSURES: No relevant relationships by Charles Eaton, source=Admin input No relevant relationships by Faeq Kukhon, source=Web Response no disclosure on file for Franklin McCool; No relevant relationships by Mahmoud Mowafy, source=Web Response No relevant relationships by Ibrahim Othman, source=Web Response No relevant relationships by Mary Roberts, source=Web Response