(HealthDay)—Adherence to a Mediterranean diet is not associated with incidence of rheumatoid arthritis (RA) in U.S. women, according to a study published in the May issue of Arthritis Care & Research.

Yang Hu, from Brigham and Women's Hospital in Boston, and colleagues conducted a prospective study involving 83,245 participants from the Nurses' Health Study (NHS) and 91,393 from NHS II to examine the correlation between a Mediterranean dietary pattern and risk of incident RA. Validated food frequency questionnaires were used to obtain dietary information every four years. Mediterranean diet was assessed using the Alternate Mediterranean Diet Score (aMed), which was calculated based on consumption status of nine food components.

During 3,511,050 person-years of follow-up, the researchers identified 913 incident cases of RA in the two cohorts. In both cohorts, adherence to Mediterranean dietary pattern was not significantly associated with the risk for RA, after adjustment for several lifestyle and dietary variables. For women in the highest versus the lowest quartile of aMed score, the pooled hazard ratio was 0.98 (95 percent confidence interval, 0.80 to 1.20). Results were similar and nonsignificant for seropositive and seronegative RA. No significant correlations were seen for individual food components of the aMed score, apart from alcohol, with the risk of incident RA.

"We did not find a significant association between a Mediterranean dietary pattern and the risk of RA in women," the authors write.

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Journal information: Arthritis Care & Research