SAT0714 Impact of pm10 on the burden of raynaud’s phenomenon secondary to systemic sclerosis
Authors: T. Schioppo, V. Bollati, S. Iodice, O. De Lucia, A. Murgo, F. Ingegnoli
Journal: Annals of the Rheumatic Diseases (2018)

<h3>Background</h3> Raynaud's phenomenon (RP) is the most frequent manifestation of patients with systemic sclerosis (SSc) and it is responsible for significant morbidity. RP has been ranked by patients with SSc as the second most disturbing related-disease symptom.<sup>1</sup> It's well known that RP, defined as episodic digital ischemia characterised by pain, numbness and digital colour changes, is provoked by environmental factors such as cold temperature and smoking exposure.<sup>2</sup> No data are available on the impact of particular matter (PM) exposure on SSc-RP severity. <h3>Objectives</h3> Our aim was to evaluate the association between PM with aerodynamic diameter ≤10 µm (PM<sub>10</sub>) and SSc-RP severity. <h3>Methods</h3> We applied multivariable continuous ordinal regression model to evaluate the association between short-term exposure to PM<sub>10</sub> and a measure of RP severity (in terms of number and duration of RP attacks, numbness, pain, burning and tingling) as measured by a Visual Analogue Scale (VAS). The model was then adjusted by sex, intravenous prostacyclin therapy (alprostar or iloprost), SSc subtype, general health (GH) VAS and season. Daily PM<sub>10</sub> concentrations, from monitoring stations measured by Regional Environmental Protection Agency (ARPA Lombardia), were used to assign short-term exposure (mean of the 3 days preceding the evaluation) to each study subjects at his/her area of residence. <h3>Results</h3> We enrolled 87 consecutive patients with SSc-RP from September 2016 to February 2017. 88.5% were female, mean age was 61 years, median time from diagnosis was 14 years (q1-q3: 7–21 years), and 10% had diffuse cutaneous SSc. The median VAS severity was 5 mm (q1-q3: 2–7 mm). 43.7% were treated with prostacyclin therapy. The model, performed as described above, estimated that for each 10 μg/m<sup>3</sup> increase in PM<sub>10</sub> there is a worsening of 40% in RP VAS severity (OR 10 μg/m<sup>3</sup>=1.40; 95% CI: 1.12–1.74). <h3>Conclusions</h3> To our knowledge a correlation between SSc-RP and air pollution as assessed by PM<sub>10</sub> has never been published before. There is increasing evidence that a number of environmental factors are fundamental in the development and course of SSc.<sup>3</sup> These results support the need to perform exposome epidemiology studies, next to genomics, to fully reveal the underlying mechanisms of diseases. <h3>References</h3> [1] Bassel M, et al. Frequency and impact of symptoms experienced by patients with systemic sclerosis: results from a Canadian National Survey. Rheumatology2011. [2] Fardoun MM, et al. Raynaud's phenomenon: a brief review of the underlying mechanisms. Front Pharmacol2016. [3] Borghini A, et al. Environmental pollution by benzene and PM<sub>10</sub> and clinical manifestations of systemic sclerosis: a correlation study. Int J Environ Res Public Health2017. <h3>Acknowledgements</h3> We thank Regional Environmental Protection Agency (ARPA Lombardia) for providing air pollution data. <h3>Disclosure of Interest</h3> None declared