Prospective associations between Mediterranean diet and mental health and quality of life in people with multiple sclerosis: Analysis of UK MS Register data.

BACKGROUND

Mediterranean diet adherence is cross-sectionally associated with better mental health and quality of life (QoL) in people living with multiple sclerosis (plwMS), but prospective associations warrant further investigation.

OBJECTIVES

To investigate prospective associations between Mediterranean diet scores and changes in mental health and QoL over 6 years in plwMS, and to explore potential sex differences.

METHODS

Data were obtained from adult plwMS in the UK MS Register at baseline and at 6-year follow-up (N = 817). The alternate Mediterranean score (aMED; range 0-9) was calculated from food frequency questionnaires. Outcomes included anxiety and depression (Hospital Anxiety and Depression Scale; HADS), psychological impact of MS (MS Impact Scale-Psychological; MSIS-29-Psych), and QoL (EQ-5D Visual Analog Scale; EQ-VAS). Prospective associations between aMED and outcomes were evaluated using quantile and log-binomial models, adjusted for baseline outcomes and relevant covariates. To test whether associations differed by sex, we added an interaction between sex and aMED in the models.

RESULTS

Overall, higher baseline continuous aMED was associated with better outcomes at 6 years, including reduced HADS-Anxiety score (aβ = -0.17; 95 %CI = -0.34, -0.01), 7 % reduced risk of abnormal depression (adjusted relative risk [aRR] = 0.93; 95 %CI = 0.87-0.99), 22 % reduced risk of high MSIS-29-Psych (aRR = 0.78; 95 %CI = 0.64-0.97), and greater QoL (aβ = 1.25; 95 %CI = 0.18-2.33). In categorical models, participants in the highest aMED tertile (≥6) vs the lowest (≤3) had a 33 % reduced risk of high MSIS-29-Psych (aRR = 0.67; 95 %CI = 0.47-0.94) and higher QoL (aβ = 6.65; 95 %CI = 1.32-11.98). Subgroup analyses showed marked sex differences in aMED associations with depression and QoL. Higher aMED was associated with lower risk of severe depression in females only (p-interaction = 0.002). Higher aMED was also linked to greater QoL in females, and lower QoL in males (p-interaction = 0.004). For anxiety and MSIS-Psych, while associations were significant in females only, group differences were not evident (p-interaction > 0.05).

CONCLUSION

Greater alignment with a Mediterranean diet was associated with better mental health and QoL over 6 years in plwMS, however, these benefits were limited to females, underscoring the importance of considering sex differences when evaluating dietary interventions. These findings support further investigations via longitudinal and clinical trials into the potential benefits of Mediterranean diet adherence in plwMS.