The association between dietary total antioxidant capacity and NMO-IgG seropositivity in patients with neuromyelitis optica spectrum disorder.

Abstract Objectives There is growing evidence highlighting the role of environmental risk factors of NMO-IgG seropositivity in patients with neuromyelitis optica spectrum disorder (NMOSD). The present study investigated the possible association between dietary total antioxidant capacity (TAC) and NMO-IgG seropositivity in NMOSD patients. Methods Fifty-six patients with a definite diagnosis of NMOSD were included in the study. Data on patients’ age, gender, height, weight, cigarette smoking status, and alcohol consumption were collected and recorded. Body mass index (BMI) was also calculated. In addition, dietary habits of patients were evaluated using an adjusted semi-quantitative food frequency questionnaire (FFQ) that consists of 168 food items. Dietary TAC was calculated using the oxygen radical absorption capacity (ORAC) method. Enzyme-linked immunosorbent assay (ELISA) method was used to determine the NMO-IgG serum status. The association between dietary TAC and odds of NMO-IgG seropositivity was measured using the logistic regression analysis. Results The mean of dietary TAC was 8362.8 (μmolTE/1000 kcal) in seronegative patients and 6609.9 (μmolTE/1000 kcal) in seropositive patients and had a significant difference between the mentioned groups of patients (P: 0.02). An inverse association was found between dietary TAC and odds of NMO-IgG seropositivity in all three regression models. The higher dietary intake of antioxidant resulted in significant findings as follows: 92% (95% CI: 0.01–0.53), 97% (95% CI: 0.00–0.34), and 97% (95% CI: 0.00–0.32) lower odds of NMO-IgG seropositivity in the fourth quartiles of the first, the second, and the third regression model, respectively. Moreover, the inverse association between fruit intake and odds of NMO-IgG seropositivity was significant in the third quartile (OR:0.10; 95%CI: 0.01–0.97). Conclusion The present study indicated a significant inverse association between dietary TAC and NMO-IgG seropositivity of NMOSD patients. As no definite treatment can be offered for NMOSD and nutrition is a modifiable factor in this regard, specification of dietary factors affecting the risk of NMOSD is of great value.