Objectives: The objective of this study is to examine the burden of depressive symptoms across the adult age span in people with multiple sclerosis (MS) and test if the relationship between depressive symptoms and MS characteristics vary across age groups.
Methods: In analyses of the MS Partners Advancing Technology and Health Solutions (MS PATHS) network of adults with MS, we compared the prevalence of depression in MS PATHS with non-MS controls across age and evaluated for effect modification by age in the association between depressive symptoms and clinical and neuroperformance measures via multivariable-adjusted regression models.
Results: In total, 13,821 individuals with MS were included. The prevalence of depression was higher in MS versus non-MS controls, but was similar between men/women across age. The association between depression and processing speed (PST; p for interaction = 0.009) or walking speed (p for interaction = 0.04) varied by age. For example, younger depressed individuals had 0.45 standard deviation (SD) (95% confidence interval (CI) = -0.62, -0.29) worse PST Z-scores versus non-depressed younger participants, whereas older depressed individuals had 0.20 SD (95% CI = -0.32, -0.08) worse PST Z-scores versus non-depressed older participants.
Conclusion: Depressive symptoms and age should be considered when interpreting measures of walking speed and cognitive function; these findings may have implications for analyses of neuroperformance change.
Keywords: Depression; aging; epidemiology.