Dietary patterns and risk of multiple sclerosis: Results of a double-center case-control study in Iran.

Background: It has been suggested that nutrition might contribute to multiple sclerosis etiology (MS). Aim: This case-control study aimed to determine the role of food habits and dietary patterns in preventing or developing MS in a multicenter study in Iran (Tehran and Shiraz). Methods: In this study, food intake of (106 patients with relapsing/remitting MS (RRMS) and 72 healthy controls in Tehran) and (75 patients with relapsing/remitting MS (RRMS) and 72 healthy controls in Shiraz) were collected using a validated semi-quantitative food frequency questionnaire. Dietary patterns were extracted using factor analysis. The association between dietary patterns and the risk of MS was analyzed by Logistic regression. Results: Two major dietary patterns were extracted: the "healthy" and the "unhealthy" patterns. After adjustment for potential confounders, in Tehran city, subjects in the highest tertile of the unhealthy dietary pattern score had greater odds of having MS, compared with those in the lowest tertile (OR: 2.16; 95% CI: [1.95-2.41]; p for trend = 0.01). In Shiraz city, subjects in the highest tertile of the unhealthy dietary pattern score had greater odds with MS than those in the lowest tertile (OR: 3.08; 95% CI: [1.27-7.38]; p for trend = 0.01). However, in both groups, no significant association was found between healthy dietary pattern and MS risk. Conclusions: Adherence to unhealthy dietary pattern may increase the risk of MS in Iran. The results can be used for developing interventions that aim to promote healthy eating for preventing MS.