Dietary inflammatory index and risk of multiple sclerosis: Findings from a large population-based incident case-control study

Abstract

Background & aims: For many decades diet, mainly its "pro-inflammatory" quality has been pondered as a possible risk factor for developing MS. However, the complexity of different dietary composition analysis provided controversial results. Recently a dietary inflammatory index (DII), a population-based score, was developed to objectify the inflammatory characteristics of a specific dietary intake. Methods: We investigated the potential association between DII (expressed as energy adjusted-DII (E-DII) and non-energy adjusted DII (DII)) assessed from a validated FFQ based on the participants' diet habits during adolescence and the risk for developing MS in a population-based incident case-control study. Multiple logistic regression was used to estimate the adjusted. Results: We recruited 547 incident MS cases and 1057 general population controls from Tehran, Iran (August 2013-February 2015). A statistically significant higher risk of MS was found in analyses using E-DII scores as a continuous variable with an adjusted odds ratio (AOR) of 1.53 (95 confidence interval (CI): 1.42-1.65, P = 0.001), and as a categorical variable (4th quartile OR 7.01, 95 CI: 4.87-10.1, vs the first quartile), test for trend; OR 1.86 (95 CI: 1.67-2.07), P for trend <0.001. A similar pattern was demonstrated for DII score and risk for MS. Conclusions: We identified a pro-inflammatory diet characterized by higher E-DII and DII scores during adolescence as a strong risk factor for MS onset. Given the worldwide role of diet in general population health, improving nutritional pattern through educational programs is likely to reduce MS risk. (C) 2020 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.