E x t e n d e d r e p o r t KHC is the recipient of an Arthritis Foundation/American College of Rheumatology Arthritis Investigator Award and a Katherine Swan Ginsburg Memorial Award. Competing interests: None declared. Ethics approval: Ethics approval was granted by the Partners Human Subjects Committee. Provenance and peer review: Not commissioned; externally peer reviewed. REFERENCES 1. Gabriel SE, Crowson CS, O’Fallon WM. The epidemiology of rheumatoid arthritis in Rochester, Minnesota, 1955-1985. Arthritis Rheum 1999;42:415–20. 2. Vessey MP, Villard-Mackintosh L, Yeates D. Oral contraceptives, cigarette smoking and other factors in relation to arthritis. Contraception 1987;35:457–64. 3. Hernandez Avila M, Liang MH, Willett WC, et al. Reproductive factors, smoking, and the risk for rheumatoid arthritis. Epidemiology 1990;1:285–91. 4. Hazes JM, Dijkmans BA, Vandenbroucke JP, et al. Lifestyle and the risk of rheumatoid arthritis: cigarette smoking and alcohol consumption. 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