Year: 2010
Type: article
Study design: Observational Study
Abstract: OBJECTIVE: This observational cohort study investigated the seasonal prevalence of multiple sclerosis (MS) disease activity (likelihood and intensity), as reflected by new lesions from serial T2-weighted MRI, a sensitive marker of subclinical disease activity. METHODS: Disease activity was assessed from the appearance of new T2 lesions on 939 separate brain MRI examinations in 44 untreated patients with MS. Likelihood functions for MS disease activity were derived, accounting for the temporal uncertainty of new lesion occurrence, individual levels of disease activity, and uneven examination intervals. Both likelihood and intensity of disease activity were compared with the time of year (season) and regional climate data (temperature, solar radiation, precipitation) and among relapsing and progressive disease phenotypes. Contrast-enhancing lesions and attack counts were also compared for seasonal effects. RESULTS: Unlike contrast enhancement or attacks, new T2 activity revealed a likelihood 2-3 times higher in March-August than during the rest of the year, and correlated strongly with regional climate data, in particular solar radiation. In addition to the likelihood or prevalence, disease intensity was also elevated during the summer season. The elevated risk season appears to lessen for progressive MS and occur about 2 months earlier. CONCLUSION: This study documents evidence of a strong seasonal pattern in subclinical MS activity based on noncontrast brain MRI. The observed seasonality in MS disease activity has implications for trial design and therapy assessment. The observed activity pattern is suggestive of a modulating role of seasonally changing environmental factors or season-dependent metabolic activity.
Source: Neurology
Language: English
Subfield: Pathology and Forensic Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
Awards: G3031958660, Harvard Clinical and Translational Science Center (UL1), HRCA/Harvard Research Nursing Home, Neuroimaging Analysis Center, Multiple Sclerosis: Molecular Profile of Plasmacytoid Dendritic Cells, Antigen Specific Therapy in CNS Autoimmune Diseases, In vivo proton MRS studies:cerebral injury in HIV infection, Mucosal Immunotherapy in a mouse model of Alzheimer's Disease, Mechanisms of the Induction of Oral Tolerance, Novel Therapies to Improve Renal and Cardiac Allograft Outcomes, Intensive Blood Pressure Reduction to Lessen Functional Decline, Gray vs. white matter brain atrophy in multiple sclerosis, G921193241
OpenAlex ID: W2084534504