As per the findings of a recently published paper in BMC Musculoskeletal Disorders journal, the fish intake solely not but its association with smoking linked to the risk of rheumatoid arthritis.
Attempts are proceeding to identify risk factors for rheumatoid arthritis (RA). Where smoking is an essential risk factor for RA, many individuals who never smoked also develop RA, this indicates the involvement of other factors such as diet and obesity as well. Other previous studies say that eating fish is a protective approach for rheumatoid arthritis (RA) risk possibly due to the anti-inflammatory influence of omega-3 fatty acid it contains, although this association has not been established explicitly. Therefore, this prospective cohort study was conducted with large sample size, repeated measures of dietary intake, and extended follow-up to assess the fish intake and RA risk by the age of onset, smoking and serologic status.

A total of 166,013 females from two prospective cohorts, the Nurses' Health Study (NHS) and NHSII were studied for evaluating the fish intake and RA risk association. Food frequency questionnaires were used to estimate the fish intake at baseline and every four years. A medical record review was utilized to assess incident RA during follow-up and serologic status. The estimated hazard ratios (HR) and 95% confidence intervals (CI) for fish intake frequency and RA was determined by applying Pooled Cox Regression. The analysis also investigated the smoking-fish synergy for RA risk.

One thousand eighty incident patients of RA were identified during the 3,863,909 person-years of follow-up. The enhanced intake of fish was not related to all RA or seronegative RA; however, had risen risk for RA diagnosed > 55 years old. The HRs of frequent fish intake (vs infrequent) for RA,  seronegative and seropositive RA among women ≤55 years old noticed to be was 0.73, 0.55, and 0.85, respectively. Smokers with frequent fish intake showed modest raised RA risk, and smokers with infrequent fish intake showed a highly elevated risk for RA onset ≤55 years. No clear protective impact of marine omega-3 fatty acid or fish intake was found on RA risk, overall or by serologic status, however, infrequent consumption of fish with smoking led to the elevated risk of RA.