High erythrocyte levels of the n-6 polyunsaturated fatty acid linoleic acid are associated with lower risk of subsequent rheumatoid arthritis in a southern European nested case-control study.

OBJECTIVES: Findings relating to dietary intake of n-3 polyunsaturated fatty acids (PUFA) and risk of rheumatoid arthritis (RA) are mixed. Erythrocyte membrane PUFA is an accurate objective biomarker of PUFA status; however, there are little data on erythrocyte membrane PUFA and risk of RA. The objective was therefore to compare erythrocyte membrane PUFA between pre-RA individuals and matched controls from a population-based sample, and specifically to test the hypothesis that higher levels of longer chain n-3 PUFA are associated with lower risk of RA. METHODS: The European Prospective Investigation into Cancer and Nutrition (EPIC) is a large European prospective cohort study of apparently healthy populations. We undertook a nested case-control study by identifying RA cases with onset after enrolment (pre-RA) in four EPIC cohorts in Italy and Spain. Confirmed pre-RA cases were matched with controls by age, sex, centre, and date, time and fasting status at blood collection. Conditional logistic regression analysis was used to estimate associations of PUFA with the development of RA, adjusting for potential confounders including body mass index, waist circumference, education level, physical activity, smoking status and alcohol intake. RESULTS: The study analysed samples from 96 pre-RA subjects and 258 matched controls. In this analysis, the median time to diagnosis (defined as time between date of blood sample and date of diagnosis) was 6.71 years (range 0.8-15). A significant inverse association was observed with n-6 PUFA linoleic acid (LA) levels and pre-RA in the fully adjusted model (highest tertile: OR 0.29; 95% CI 0.12 to 0.75; P for trend 0.01). No association was observed with any individual n-3 PUFA, total n-3 PUFA or total n-3:n-6 ratio. CONCLUSIONS: Erythrocyte levels of the n-6 PUFA LA were inversely associated with risk of RA, whereas no associations were observed for other n-6 or n-3 PUFA. Further work is warranted to replicate these findings and to investigate if lower LA levels are a bystander or contributor to the process of RA development.

Acupuncture for pain relief in patients with rheumatoid arthritis: a systematic review.

OBJECTIVE: To systematically review the efficacy of acupuncture on pain relief in patients with rheumatoid arthritis (RA). METHODS: We performed a comprehensive search of 12 western and Chinese databases and reference lists through March 2008. We included randomized controlled trials with pain as an end point, measured by tender joint count (TJC) or a pain scale. We also reviewed the effect of acupuncture on morning stiffness, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) level. Study quality was assessed by Jadad score. Differences between treatment groups were pooled as mean or median change (P value). RESULTS: Eight studies met eligibility criteria with a total of 536 subjects. There were 4 placebo-controlled trials and 4 active-controlled trials. Average study duration was 11 weeks. Mean +/- SD acupuncture points and sessions were 11 +/- 8 and 42 +/- 62, respectively. Average duration of needle insertion was 24 minutes. Six studies reported a decrease in pain for acupuncture versus controls; the mean or median changes of acupuncture-decreased TJC pain ranged from 1.5 to 6.5. In addition, 4 studies reported a significant reduction in morning stiffness (mean change -29 minutes), but the difference was nonsignificant versus controls. With regard to inflammatory markers, 5 studies observed a reduction in ESR (mean change -3.9 mm/hour) and 3 observed a CRP level reduction (mean change -2.9 mg/dl); only 1 study showed a significant difference for both ESR and CRP. CONCLUSION: Despite some favorable results in active-controlled trials, conflicting evidence exists in placebo-controlled trials concerning the efficacy of acupuncture for RA. Rigorous and well-controlled randomized trials are warranted.