Sodium intake and multiple sclerosis activity and progression in BENEFIT

Area of Science:

• Neurology
• Immunology
• Dietary Science

Background:

• Dietary factors, including salt intake, are increasingly investigated for their role in autoimmune diseases.
• High salt consumption has been linked to various health issues, prompting research into its effects on neurological conditions like multiple sclerosis (MS).
• Understanding modifiable lifestyle factors is crucial for managing chronic conditions such as MS.

Purpose of the Study:

• To determine if a high-salt diet, indicated by urinary sodium concentration, accelerates the conversion from clinically isolated syndrome (CIS) to MS.
• To investigate the association between salt intake and MS disease activity, including clinical and magnetic resonance imaging (MRI) outcomes.
• To evaluate the impact of sodium excretion levels on disability progression, measured by the Expanded Disability Status Scale (EDSS).

Main Methods:

• The study analyzed data from the BENEFIT randomized clinical trial, involving 465 patients with CIS.
• Urinary sodium excretion was estimated using the Tanaka equations based on repeated spot urine samples collected over a 5-year follow-up period.
• Associations between cumulative average sodium levels and clinical outcomes (MS conversion, EDSS, relapse rate) and MRI outcomes (lesion volume, active lesions) were assessed.

Main Results:

• No significant association was found between average 24-hour urine sodium levels and conversion to clinically definite MS over the 5-year follow-up.
• Salt intake did not correlate with key clinical outcomes, including changes in EDSS or relapse rates.
• MRI-assessed MS activity, such as new active lesions and T2 lesion volume changes, also showed no significant link to estimated daily sodium intake.

Conclusions:

• This research, utilizing multiple urine sodium measurements and standardized follow-up, suggests that dietary salt intake does not influence the disease course or activity in patients with MS.
• The findings indicate that salt consumption is unlikely to be a significant factor in MS progression or exacerbation.
• Further research may explore other dietary components or lifestyle factors in MS management.