In patients with rheumatoid arthritis (RA), higher fish consumption was associated with lower disease activity, according to results of a recent clinical trial (Tedeschi SK, et al. Arthritis Care Res [Hoboken]. 2017 June 21. Epub ahead of print).
In this study, the investigators analyzed baseline data from 176 patients with RA enrolled in the Evaluation of Subclinical Cardiovascular Disease and Predictors of Events in RA cohort study from October 2004 to May 2006. Patients who had a previous cardiovascular event or who weighed >300 lb were ineligible.
The majority of participants were white, middle-aged, college-educated women who were taking disease-modifying antirheumatic drugs for seropositive, long-standing RA. Of the 176 participants, 19.9% were infrequent fish eaters (ie, never to <1 time monthly) and 17.6% ate fish frequently (ie, ≥2 times weekly). Participants had a median Disease Activity Score 28-joint count C-reactive protein (DAS28-CRP) of 3.5, which indicated moderate RA disease activity.
“We report a statistically and clinically significant reduction in DAS28-CRP among subjects with rheumatoid arthritis who consumed fish ≥2 times/week compared to those who consumed fish never or <1/month, after adjustment for confounders,” said Sara K. Tedeschi, MD, MPH, Instructor in Medicine, Division of Rheumatology, Immunology, and Allergy, Brigham and Women’s Hospital, Harvard Medical School, Boston, and colleagues.
At baseline, participants completed a 120-item food frequency questionnaire that evaluated their typical diet during the past year. They recorded the frequency with which they ate fish on a 9-point scale, ranging from never to <1 time monthly to ≥2 times daily, and indicated each serving size as small, medium, or large.
For the purposes of the study, fish consumption was defined as sardines, tuna, salmon (including sashimi and sushi), as well as other broiled, steamed, baked, or raw fish (eg, trout, sole, halibut, poke, and grouper). These types of fish were included because they contain higher omega-3 fatty acids than other variations. Consumption of fried fish, nonfried shellfish, and fish used in mixed dishes (eg, stir-fried shrimp or fish with vegetables) was not included.
Dr Tedeschi and colleagues analyzed the association between how much fish participants ate and their baseline DAS28-CRP, after adjusting for factors such as age, sex, biologic disease-modifying antirheumatic drug use, fish oil supplement use, depression, smoking status, and body mass index. They found that participants who ate baked, steamed, broiled, or raw fish ≥2 times weekly had a significantly lower DAS28-CRP compared with those who never ate fish or ate it <1 time monthly. The difference in DAS28-CRP between the 2 groups was –0.49 (95% confidence interval [CI], –0.97 to –0.02). With each additional serving of fish per week, DAS28-CRP dropped significantly by 0.18 (95% CI, –0.35 to –0.004).
“The observed difference in mean DAS28-CRP between the highest and lowest categories of fish consumption is of clinically important magnitude,” Dr Tedeschi and colleagues asserted.
Participants who ate fish most frequently had some baseline traits that may have been associated with improved disease activity, such as lower body mass index and higher socioeconomic status, although this cohort also had the highest prevalence of smoking and the longest disease duration, making it difficult to determine how confounders may affect the relationship between fish consumption and RA disease activity.
“We observed significantly lower DAS28-CRP among subjects consuming fish ≥2 times/week compared to those eating fish never or <1/month. Prospective assessment of disease activity in relationship to fish consumption is warranted,” Dr Tedeschi and colleagues concluded.