Background Recently, we showed that exposure to outdoors pollutants was associated with an increase of hospitalizations in paediatric rheumatic diseases (1) and higher risk of disease activity in our childhood-onset systemic lupus erythematous (cSLE) patients (2).Exhaled breath biomarkers measurements, such as exhaled breath condensate (EBC) and fractional concentration of exhaled nitric oxide (FeNO) may indicate airways inflammation related to air pollutant exposure. To our knowledge, this was the first study that showed the effects of daily exposure to PM2.5, assessed by personal real time monitoring, on airway inflammation and increased risk of disease activity in cSLE patients.
Objectives To investigate the association between daily individual real-time exposure to air pollutants and disease activity in cSLE patients.
Methods A longitudinal panel study was carried-out in 108 consecutive visits of cSLE patients. During four consecutive weeks, daily personal measures of nitrogen dioxide (NO2), fine particulate matter (PM2,5), ambient temperature and humidity were obtained.This cycle was repeated every 2.5 months along one year and pH of exhaled breath condensate (EBC pH), fractional exhaled NO (FeNO) and disease activity parameters were collected weekly. Specific generalized estimation equation models were used to assess the impact of these pollutants on the risk of moderate/severe disease activity (SLEDAI-2K≥8), EBC pH and FeNO considering the fixed effects for repetitive measurements. The models were adjusted for inflammatory indicator, body mass index, infection, medication and weather variables.
Results For an interquartile range increase of 18.12μg/m3 in PM2.5 daily concentration we observed an increased short-term effect in FeNO at the first three days (lag 0 to lag 2) after exposure. The 3-day moving average effect on FeNO was an increase of 0.75 ppb (95%IC: 0.38–1.29). Decreases in EBC pH were evidenced at days 7 and 10 after exposure [0.09 (95%IC: 0.15–0.02); 0.09 (95%IC: 0.17–0.01) respectively]. Regarding the risk of SLEDAI-2K ≥8, an increase of 18.12 μg/m3 in PM2.5 was associated with increases in the risk of SLEDAI-2K ≥8 at four [RR 1.45 (95%CI: 1.24–1.66)] and 11 days [RR 1.34 (95%CI: 1.05–1.62)] after exposure.
Conclusions Real-time exposure to air pollution may have a role in triggering disease activity and airways inflammation in cSLE patients.
Vidotto JP, Pereira LAA, Braga ALF et al. Atmospheric pollution:influence on hospital admission in pediatric rheumatic disease. Lupus. 2012;21:526–33
Fernandes EC, Silva CA, Braga ALF, Sallum AM, Campos LM, Farhat SC. Exposure to air pollutants increased disease activity in childhood-onset systemic lupus erythematosus patients. Arthritis Care Res. 2015; 67:1609–14.
Acknowledgement Supported by Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP 13/21508–2), Conselho Nacional de Desenvolvimento Científico e Tecnolόgico (CNPQ 302724/2011–7 and 472155/2012–1), Federico Foundation and Núcleo de Apoio à Pesquisa “Saúde da Criança e do Adolescente” da USP (NAP-CriAd).
Disclosure of Interest None declared