No association between Borrelia burgdorferi antibodies and amyotrophic lateral sclerosis in a case-control study

Previous studies, mostly case reports and uncontrolled studies, provide a low level of evidence for the hypothesized link between Lyme disease and amyotrophic lateral sclerosis (ALS). In order to make evidence-based recommendations regarding testing for Borrelia burgdorferi antibodies in the diagnostic work-up for ALS, the objective of this study was to explore the evidence for an association between these antibodies and ALS in a case-control design including age-, gender- and residency-matched controls.

A total of 491 patients with ALS were matched to 982 controls. IgG titers against B. burgdorferi were determined by an enzyme-linked immunosorbent assay and, in the case of positivity or borderline results, a western blot was performed. Conditional logistic regression and Fisher's exact tests were used to compare the antibody titers or positivity between patients and controls.

No difference in seroprevalence of Borrelia was found between patients (4.1%) and controls (5.9%). Clinical characteristics and survival were similar between seropositive and seronegative patients. Moreover, patients with a spinal onset were not more frequently seropositive compared with patients with a bulbar onset (P = 0.47), and neither were patients with a short diagnostic delay of <6 months compared with controls (P = 0.69). None of the 20 patients with a diagnostic delay of <3 months tested positive for IgM antibodies, suggestive of a recent infection.

This large case-control study provides evidence for a lack of association between B. burgdorferi antibodies and ALS, and therefore does not support the inclusion of routine testing for these antibodies in the diagnostic work-up in patients with classical ALS.