Diet and omega-3 and vitamin D supplement use predict five-year fatigue and disability trajectories in people with multiple sclerosis

Background Fatigue and disability are indicators of disease progression experienced by many people with multiple sclerosis (pwMS). Understanding trajectories of these outcomes, and their predictors, may provide insight to potential interventions for MS management. Methods Survey data from 839 pwMS from the Health Outcomes and Lifestyle in pwMS study were analysed. Fatigue was defined as mean Fatigue Severity Scale >5, and severe disability as Patient Determined Disease Steps >5. Group-based trajectory modelling was used to identify fatigue and disability trajectories over five-years. Dietary predictors associated with outcome trajectory group membership were assessed using log-binomial regression. Demographic and clinical characteristics were considered in multivariable models. Results Distinct trajectories for fatigue and disability were identified. For fatigue, 58% of pwMS were assigned to low-, and 42% to high-, fatigue trajectory groups. For disability, 85% of pwMS were assigned to low-, and 15% to high-, disability groups. Baseline high-quality diet, and omega-3 and vitamin D supplement use, were associated with reduced risk of being in high-fatigue and high-disability trajectories, while meat and dairy consumption were associated with increased risk. Conclusions A high-quality diet, avoiding meat and dairy, and omega-3 and vitamin D supplement use, individually predict better fatigue and disability trajectories. Dietary modifications should be considered in MS management.