Background: Epidemiological, pathological and radiological studies suggest that inflammatory demyelination in MS is an age-dependent process, and that the formation of focal inflammatory demyelinating lesions decreases with age. Gadolinium-enhancing lesions are a biomarker of inflammatory disease activity in MS, but little is known about the relation of age and gadolinium enhancement on cranial MRI scans in people with MS. In this study, we investigated the association of age and other risk factors with gadolinium enhancement on cranial MRI in a retrospective cross-sectional clinical MS cohort.
Methods: In a cohort including 1543 people with CIS and MS, we investigated the association of the risk factors age, sex, disease course, immunomodulatory drug (IMD) treatment, and disability with gadolinium enhancement on cranial MRI scans using a binary logistic regression model.
Results: Age was the most important factor associated with gadolinium enhancement, with the odds of gadolinium enhancement decreasing with advancing age. Participants with CIS had lower odds of gadolinium enhancement (odds ratio of 0.42, 95% confidence interval of 0.24-0.72 compared to RRMS). Sex, disease course and IMD treatment were not significantly associated with gadolinium enhancement in our cohort.
Conclusions: Our investigation shows that gadolinium enhancement is strongly associated with age. Since gadolinium enhancement is a marker of inflammatory disease activity, our findings suggest that inflammatory disease activity declines with age, and that IMD treatment may be more beneficial in younger and less useful in older people with MS.
Keywords: Aging; Clinically isolated syndrome; Magnetic resonance imaging; Multiple sclerosis.