Background Occupational exposure to silica dust is associated with increased risk of developing ACPA positive Rheumatoid arthritis (RA). Little is known about non-occupational exposure, as there are no available tools to assess it in clinical practice.The Dust Exposure Life-Course Questionnaire (DELCQ), developed within the SILICOSIS project, a European Research Council Advanced Grant, provides clinical research with a tool derived from social sciences. The DELCQ allows to quantify both occupational and non-occupational (e.g. body care; hobbies such as DIY, woodworking, stone cutting, etc..) exposure to silica and some other inorganic particles during the whole lifetime.In the DELCQ, the identification of sources of exposure is grounded on an extensive list of products and activities summed up by the International Agency on Research on Cancer and on a wide overview of the literature addressing silica exposure and silica-related (or suspected-to-be-related) diseases.Objectives To explore occupational and non-occupational silica exposure in a series of consecutive RA patients and the association of quantified silica dust exposure with major disease features (ACPA positivity) or outcomes (erosive disease).Methods The DELCQ was administered to 97 consecutive RA patients (77F, 20M, mean age 59.1+/- 13.3 yrs.,75 ACPA positives, 66 with erosive disease) attending the rheumatology department of Avicenne Hospital (Bobigny, FRANCE). The DELCQ scores of patients were compared to those of 388 controls, matched for sex, age and smoking status, from a 2739-subject national cohort, representative of the general French population (ELIPSSilice). Within RA subjects, the association of the scores with ACPA positivity and with erosive disease was assessed after adjustment for tobacco use.Results RA patients had higher median scores of occupational (10 [0, 17] vs. 0 [0, 4]) exposure vs. controls (p5 pack/y vs. nonsmokers or smokers