Smoking May Accelerate White Matter Damage in Progressive MS

The relationship between microstructural damage in NAWM and clinical measures was less clear, suggesting another mechanism.

Smoking may accelerate microstructural damage in progressive multiple sclerosis (MS), according to results from a cross-sectional study. The findings were presented at the 32nd European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS) Congress, September 14-17, 2016 in London.

Smoking has previously been linked to MS disease progression; however data on its effects in progressive MS and its correlation with other measures of disease progression is scarce.

In this study, Cecilie Ammitzboell, MD, of the Danish Multiple Sclerosis Center at Cophenhagen University Hospital Rigshospitalet, in Denmark, and colleagues collected clinical and MRI data from 93 patients with progressive MS; 37 with primary progressive MS (PPMS) and 56 with secondary progressive MS (SPMS). Patients were categorized by smoking status (current or non-) and completed the Expanded Disability Status Scale (EDSS) and multiple sclerosis functional composite (MSFC) test, which included the 9-hole peg test (9HPT), timed 25-foot walk (T25FW), and paced auditory serial addition test (PASAT). Patients underwent 3T MRI, from which T2 lesion volume was extracted. Microstructural changes in lesions, normal appearing white matter (NAWM), and cortical grey matter (CGM) were also assessed and estimated based on magnetization transfer ratio (MTR) and diffusion weighted imaging.

After correlation and univariate analyses, lesion volumes were found to correlate with all clinical measures, including EDSS (P =.286, Q =.043), 9HPT (P =.312, Q =.041), T25FW (P =.313, Q =.047) and PASAT (P =-.303, Q =.044). In lesions, EDSS scores correlated with MTR (P =-.278, Q =.048) and T25FW and PASAT scores correlated with mean diffusivity values (P =.278, Q =.049 respectively). In NAWM, fractional anisotrophy correlated with 9HPT (P =-.359, Q =.043). Notably, fractional anisotrophy was lower in NAWM in smokers than in non-smokers (P =.019).

The relationship between microstructural changes in NAWM and clinical measures is less clear that that between scores of clinical disability, lesion volume, and microstructural changes, suggesting that smoking may accelerate microstructural damage.

The authors report several disclosures. See the abstract for the full listing.

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Ammitzbøll C, Dyrby T, Lyksborg M, et al. Clinical disability and smoking are associated with MRI disease activity in progressive multiple sclerosis. Presented at: ECTRIMS 2016. September 14-17, 2016; London, UK. Poster 1022.