Overweight decreases the chance of achieving good response and low disease activity in early rheumatoid arthritis.

AIM: To investigate whether overweight/obesity at diagnosis affects the chances of decrease in disease activity and pain in early rheumatoid arthritis (RA). METHOD: We investigated incident RA cases from the population-based Epidemiological Investigation of risk factors for Rheumatoid Arthritis (EIRA) study (2006-2009, N=495) with clinical follow-up in the Swedish Rheumatology Quality Register. At diagnosis, 93% received disease-modifying antirheumatic drugs (DMARDs) (86% methotrexate). The odds of achieving a good response according to the DAS28-based European League Against Rheumatism (EULAR) criteria, low disease activity (DAS28<3.2), remission (DAS28<2.6) or pain remission (visual analogue scale ≤20 mm) at 3-months and 6-months follow-up, were calculated using logistic regression, adjusting for potential confounders. RESULTS: Significant dose-response relationships were found between Body Mass Index (BMI) and change of disease activity as well as pain at both time points. Patients with BMI ≥25 had 51% lower odds of achieving low disease activity (odds ratio (OR=0.49 (95% CI 0.31 to 0.78)) and 42% lower odds of remission (OR=0.58 (95% CI 0.37 to 0.92)) at the 6-months visit, compared to normal-weight patients. This effect was also present at 3 months, where we also found a 43% decreased odds of pain remission (OR=0.57 (95% CI 0.37 to 0.88)). No effect modification was found for anti-citrullinated protein antibody (CCP)-status, sex, prednisolone treatment or DAS28 at diagnosis. CONCLUSIONS: Overweight at diagnosis significantly decreases the chance of achieving good disease control during the early phase of RA.

Association between body mass index and anti-citrullinated protein antibody-positive and anti-citrullinated protein antibody-negative rheumatoid arthritis: results from a population-based case-control study.

OBJECTIVE: Being overweight or obese is associated with many chronic diseases, but previous studies of the association with rheumatoid arthritis (RA) have shown inconsistent results. The aim of this study was to investigate the association between body mass index (BMI) and the risk of developing the 2 main subtypes of RA. METHODS: At inclusion, cases and controls answered questions about their weight and height and donated blood samples. The presence of antibodies to citrullinated protein antigens (ACPAs) was analyzed among 2,748 cases and 3,444 controls (28% men). Odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated using conditional logistic regression. RESULTS: Compared to those with normal weight (BMI <25 kg/m(2) ), the adjusted overall OR for developing ACPA-negative RA was 1.1 (95% CI 0.9-1.3) for overweight individuals (BMI ≥25 to <30 kg/m(2) ) and 1.4 (95% CI 1.1-1.9) for obese individuals (BMI ≥30 kg/m(2) ). When stratified by sex, the OR for ACPA-negative RA for obese women was 1.6 (95% CI 1.2-2.2), and there was no association between obesity and ACPA-negative RA in men (OR 1.1, 95% CI 0.6-1.8). In obese men compared to men with normal weight, the OR for ACPA-positive RA was 0.6 (95% CI 0.3-0.9), while there was no association between BMI and ACPA-positive RA among women (OR 1.0, 95% CI 0.8-1.2). CONCLUSION: Our findings show that obesity is associated with developing ACPA-negative RA in women, and indicate an inverse association between BMI and ACPA-positive RA in men.

Patients with early rheumatoid arthritis who smoke are less likely to respond to treatment with methotrexate and tumor necrosis factor inhibitors: observations from the Epidemiological Investigation of Rheumatoid Arthritis and the Swedish Rheumatology Register cohorts.

OBJECTIVE: To determine whether cigarette smoking influences the response to treatment in patients with early rheumatoid arthritis (RA). METHODS: We retrieved clinical information about patients entering the Epidemiological Investigation of Rheumatoid Arthritis (EIRA) early RA cohort from 1996 to 2006 (n=1,998) who were also in the Swedish Rheumatology Register (until 2007). Overall, 1,430 of the 1,621 registered patients were followed up from the time of inclusion in the EIRA cohort. Of these, 873 started methotrexate (MTX) monotherapy at inclusion, and 535 later started treatment with a tumor necrosis factor (TNF) inhibitor as the first biologic agent. The primary outcome was a good response according to the European League Against Rheumatism criteria at the 3-month visit. The influence of cigarette smoking (current or past) on the response to therapy was evaluated by logistic regression, with never smokers as the referent group. RESULTS: Compared with never smokers, current smokers were less likely to achieve a good response at 3 months following the start of MTX (27% versus 36%; P=0.05) and at 3 months following the start of TNF inhibitors (29% versus 43%; P=0.03). In multivariate analyses in which clinical, serologic, and genetic factors were considered, the inverse associations between current smoking and good response remained (adjusted odds ratio [OR] for MTX response 0.60 [95% CI 0.39-0.94]; adjusted OR for TNF inhibitor response 0.52 [95% CI 0.29-0.96]). The lower likelihood of a good response remained at later followup visits. Evaluating remission or joint counts yielded similar findings. Past smoking did not affect the chance of response to MTX or TNF inhibitors. Evaluating the overall cohort, which reflects all treatments used, current smoking was similarly associated with a lower chance of a good response (adjusted ORs for the 3-month, 6-month, 1-year, and 5-year visits 0.61, 0.65, 0.78, 0.66, and 0.61, respectively). CONCLUSION: Among patients with early RA, current cigarette smokers are less likely to respond to MTX and TNF inhibitors.

Dietary fish and fish oil and the risk of rheumatoid arthritis.

BACKGROUND: Intake of fish oil and oily fish has been reported to improve clinical symptoms in people who have rheumatoid arthritis. Whether the intake of oily fish and fish oil might also protect against the development of rheumatoid arthritis is not known. OBJECTIVE: We investigated the association between intake of oily fish and fish oil supplements and the risk of rheumatoid arthritis in a population-based case-control study. METHODS: The study comprised 1889 incident cases of rheumatoid arthritis and 2145 randomly selected controls recruited from a geographically defined area of Sweden during 1996-2005. Data on the consumption of oily fish and fish oil supplements 5 years preceding enrollment had been obtained through a questionnaire. We calculated odds ratios (ORs) for the development of rheumatoid arthritis, using logistic regression to adjust for age, residential area, body mass index, smoking, and alcohol consumption. RESULTS: Compared with subjects who never or seldom consumed oily fish, the OR for developing rheumatoid arthritis was 0.8 (95% confidence interval = 0.6-1.0) for subjects who consumed oily fish 1-7 times a week. The results did not change notably when stratifying the cases for rheumatoid factor or for antibodies to citrullinated peptide antigens. Similar results were seen for subjects consuming oily fish 1-3 times a month. Cases and controls did not differ in their consumption of fish oil supplements. CONCLUSION: Intake of oily fish was associated with a modestly decreased risk of developing rheumatoid arthritis.