PARIS — Heavy coffee drinking was associated with progression of undifferentiated arthritis to rheumatoid arthritis in an analysis of data from a Norwegian early arthritis clinic.
The study included 280 patients aged 18–75 years with arthritis of at least one joint. The mean age was 45.7 years, median disease duration was 23 days, and 55% were women, Dr. Maria D. Mjaavatten said at the annual European Congress of Rheumatology.
Data were collected from a structured patient history. Examinations included swollen and tender joint counts, measurement of C-reactive protein and erythrocyte sedimentation rate, and patient-reported health status.
At baseline, 130 patients had monoarthritis, 96 had oligoarthritis, and 54 had polyarthritis. At 1 year, 30 of these patients (10.7%) had developed rheumatoid arthritis (RA). Multivariate analysis showed the strongest predictor of RA development was a positive titer of anti-cyclic citrullinated peptide (CCP) at presentation, with an odds ratio of 73.23.
But drinking 10 or more cups of coffee daily also was associated with an elevated risk (OR, 22.50), Dr. Mjaavatten of the department of rheumatology, Diakonhjemmet Hospital, Oslo, wrote in a poster.
The link of coffee intake with RA also was seen in earlier studies. In the Mini-Finland Health Survey, carried out between 1978 and 1980, the odds ratio for RA was 14.80 in those with a daily coffee intake of 11 or more cups. After adjustment for confounders including age, sex, smoking, alcohol intake, body mass index, and serum cholesterol, the relative risk was 2.20 for those drinking four or more cups of coffee daily (Ann. Rheum. Dis. 2000;59:631–5).
A study from Iowa implicated decaffeinated coffee. Researchers reported that subjects who drank four or more cups a day had a relative risk of 2.58 for RA, suggesting that exposure to the solvents used for extracting caffeine before the mid-1970s might have played a role (Arthritis Rheum. 2002;46:83–91).
A case-control study in Denmark between 2002 and 2004 found that subjects who were shared epitope carriers and smoked, drank more than five cups of coffee each day, or used oral contraceptives were at high risk for anti-CCP-positive RA.
The researchers cited the hypothesis that exposure to environmental stimuli might be a primary triggering event for RA, with tobacco smoke being the prototype because it induces the presentation of citrullinated autoantigens in the lungs in genetically predisposed persons, which activates the adaptive immune response. They suggested coffee also might operate in this citrullination process, contributing to anti-CCP-positive RA (Arthritis Rheum. 2007;56:1446–53).
Further investigation of coffee intake in RA development is needed, Dr. Mjaavatten said, noting her results should be interpreted with caution, because the RAincidence was low in this cohort.