The role of dietary antioxidant index and index of nutritional quality in MS onset: finding from an Iranian population-based incident case–control study

Introduction: The role of nutritional factors in MS etiology is a matter of debate. Employing dietary antioxidant index (DAI) as well as index of nutritional quality (INQ) we aimed to investigate the possible link between diet and MS risk. Methods: This was a large population-based case–control study recruiting 547 incident cases and 1057 population controls between August 2013 and February 2015. DAI and INQ were calculated based on the adolescence dietary intake of the participants. Logistic regression was employed for estimating adjusted odds ratios (OR) and their 95% confidence interval in 2018. Results: Participants with less than median DAI values had two-fold increased risk of MS onset (adjusted OR 2.05, 95% CI: 1.64–2.58, P < 0.001). A significant dose–response pattern for DAI (adjusted OR 1.35, 95% CI: 1.18–1.55, P for trend <0.001) was also detected. In the case of INQ, the strongest decreased risk were detected for vitamin D (OR = 0.09) and Zinc (OR = 0.34), followed by vitamin A (OR = 0.49), Calcium (OR = 0.49) and vitamin B6 (OR = 0.51) (All P-values < 0.05). Conclusion: Considering the inherent limitation of case–control designs, an appropriate intake of nutrient antioxidants may have a role in decreasing the likelihood of MS risk. Moreover, those with healthier diet assessed by index of nutritional quality were at decreased risk for MS.