Serum homocysteine levels in relation to clinical progression in multiple sclerosis

Elevated homocysteine levels are associated with various neurodegenerative diseases and have even been identified as a risk factor for some of these. Homocysteine levels may be elevated in patients with multiple sclerosis (MS) but large studies are lacking and the relation with disease progression remains to be determined.

The aim of the study was to investigate homocysteine levels in patients with MS and in controls, and to study the relationship between homocysteine levels and clinical progression in MS.

Serum homocysteine levels were compared between MS subtypes (n = 219) and controls (n = 152). Homocysteine levels were associated with baseline and follow-up clinical severity scores.

The results showed that serum homocysteine values were similar in patients with MS and controls. Baseline scores on the Expanded Disability Status Scale were higher in patients with secondary progressive MS (SPMS) in the top compared with the bottom quartile of homocysteine levels (p = 0.02). The baseline scores on the Multiple Sclerosis Functional Composite (MSFC) and Paced Auditory Serial Addition Test (PASAT), which measures cognitive functioning, were lower in patients with SPMS in the top compared with the bottom quartile of homocysteine levels (MSFC, p = 0.02; PASAT, p = 0.02). High homocysteine levels were associated with a decline in PASAT scores during follow-up in patients with primary progressive MS (p = 0.009).

Serum total homocysteine levels are associated with several measures of disease progression in MS but are not elevated in patients with MS compared with controls. The association of homocysteine levels with cognition in patients with progressive MS raises the question of whether homocysteine directly impacts on MS or reflects a more general neurodegenerative process.