Background. Rheumatoid arthritis (RA) flare is related to an increased joint damage, disability and healthcare use. The impact of short-term air pollution exposure on RA activity is still a matter of debate. We investigated in a cross-sectional study whether short-term exposure to particulate matter (PM)10, PM2.5, nitrogen dioxide (NO2) and ozone (O3) affected RA disease activity. Methods. 422 consecutive RA patients resident in Lombardy, North of Italy were studied. Air pollutant concentrations, estimated by Regional Environmental Protection Agency (Lombardy – Italy) at municipality resolution, were used to assign short-term exposure from the day of visit back to 14 days. Results. Sparse punctual significant negative associations emerged between PM10, PM2.5, NO2 and RA disease activity, whereas positive associations were observed for O3. Moreover, patients were stratified according to their ongoing Disease Modifying anti-Rheumatic Drugs (DMARDs) treatment: no DMARDs (n=25), conventional synthetic - csDMARDs (n=108), and biological or targeted synthetic b/tsDMARDs (n=289). At visit, an inverse association was observed in the b/tsDMARDs group between PM2.5 and Disease Activity Score on 28 joints (DAS28) (-0.047±0.020, p=0.023), a positive tendency in the no-DMARD group (0.125±0.070, p=0.075) and no association for csDMARDs group (0.042±0.039, p=0.288). The association between O3 the day before the visit and DAS28 was positive only in the b/tsDMARDs group (0.038±0.009, p<0.001). Conclusion. The impact of air pollution short-term exposure seems minimally clinical relevant, as the scattered significant differences were observed. Further evidence is needed to elucidate determinants of RA flare and the implications for management.

Objective. Exposure to airborne pollutants during pregnancy appears to be associated with uterine growth restriction and adverse neonatal outcome. Proprotein convertase subtilisin/kexin type (PCSK9) is a key modulator of low-density lipoprotein (LDL) metabolism, and increases following short term particulate matter (PM10) exposure. Because maternal cholesterol is required for fetal growth, PCSK9 levels could be used to evaluate the potential impact of airborne pollutants on fetal growth. Design. A cohort of 134 healthy women during early pregnancy (11–12 weeks of gestational age) was studied. Results. A significant association was found between circulating PCSK9 levels and three tested air pollutants (PM10, PM2.5, nitric oxide (NO2)). Of importance, gestational age at birth was reduced by approximately 1 week for each 100 ng/mL rise in circulating PCSK9 levels. This effect became more significant at the highest quartile of PM2.5 (with a 1.8 week advance in delivery date for every 100 ng/mL rise in circulating PCSK9). This finding was supported by a significant elevation of the odds ratio for urgent cesarean delivery for each 100 ng/mL rise in PCSK9 (2.99, 95% CI, 1.22–6.57), with similar trends being obtained for PM10 and NO2. Conclusions. The association between exposure to air pollutants during pregnancy and elevation in PCSK9 advances our understanding of the unforeseen influences of environmental exposure in terms of pregnancy associated disorders.