The relationship between exposure to air pollution and spondyloarthritis (SpA) has been poorly studied. Based on data from the literature on other inflammatory pathologies such as rheumatoid arthritis, we hypothesize that there is a relationship between exposure to air pollution and the risk of presenting a flare-up in SpA patients following and living in Franche-Comté (France).

Primary objective:The potential relationship between exposure to air pollution (nitrogen dioxide, fine particles with a diameter of less than 10 or 2.5 microns and Ozone) and the onset of a spondyloarthritis flare-up will be explored in patients with this pathology.

Inclusion Criteria:

• Diagnosis of Axial Spondyloarthritis (radiographic or non-radiographic) according to Assessment of SpondyloArthritis international Society (ASAS) criteria
• Patient having received a consultation / hospitalization during the period 2019-2022
• Patient enrolled in the MISTIC cohort
• Having lived in Franche-Comté during the 2019-2022 period.

Exclusion Criteria:

• Other chronic inflammatory rheumatism (rheumatoid arthritis according to ACR 2010 criteria or psoriatic arthritis according to ClASsification criteria for Psoriatic ARthritis criteria)
• No inflammatory rheumatic disease

Patients with a diagnosis of Axial Spondyloarthritis, received in rheumatology consultation/hospitalization over the period 2019-2022 and living in Franche-Comté over the same period.