Air Pollution and Systemic Inflammation in Patients With Suspected OSA Living in an Urban Residential Area

Air pollution and OSA are independently associated with systemic inflammation, but it is unknown if these exposures interact to influence systemic inflammation. The study objective was to determine the relative importance of these factors and their combined potential to influence systemic inflammation in patients under assessment for sleep ailments. A total of 315 patients contributed data, including a questionnaire, polysomnogram, and morning serum IL-6 and IL-10 concentrations. For each patient, residential annual average air pollution exposure (nitrogen dioxide [NO2], black carbon [BC], and particulate matter with an aerodynamic diameter ≤ 2.5 μm [PM2.5]) was estimated with a land use regression model. Linear regression modeling was used adjusting for age, sex, apnea-hypopnea index, BMI, smoking, socioeconomic status, and comorbidities. In adjusted models, quartile 4 PM2.5 exposure (compared with quartiles 1-3) was associated with increased IL-6 and IL-10 concentrations (estimated adjusted, 7.1 pg/mL [95% CI, 2.5-11.7; P < .01] and 71.4 pg/mL [95% CI, 38.2-103.7; P < .0001], respectively). OSA, BC, and NO2 were not associated with IL-6 or IL-10 in similar analyses; however, moderate to severe OSA influenced the effect of BC on IL-6 (interaction term, P = .01), with no significant interaction terms observed for NO2 or PM2.5. Subsequent stratified analysis showed that in the 173 patients with moderate to severe OSA, quartile 4 BC exposure (compared with quartiles 1-3) was associated with an increased IL-6 concentration (estimated adjusted, 8.9 pg/mL; 95% CI, 1.7-16.1; P = .02). Long-term residential PM2.5 exposure was associated with increased IL-6 and IL-10 concentrations in patients evaluated for suspected OSA. BC exposure was also associated with increased IL-6 but only in the subgroup of patients with moderate to severe OSA. These data suggest the potential for joint effects of moderate to severe OSA and air pollution on systemic inflammation.