Gait Speed and the Natural Course of Depressive Symptoms in Late Life; An Independent Association With Chronicity?

Abstract

IntroductionPsychomotor slowing is a core feature of depression in late life, but its prognostic value with respect to course and chronicity is unclear. We investigated whether gait speed can predict chronicity of depressive symptoms. Furthermore, we tested whether (1) cognitive slowing and (risk factors for) vascular diseases, (2) a marker of chronic inflammation, and (3) specific somatic conditions could explain this association. MethodsIn the population-based Longitudinal Aging Study Amsterdam, 271 aged participants with clinically relevant depressive symptoms (Center for Epidemiologic Studies Depression Scale ≥16) were followed during a period of 6 years. With 14 successive Center for Epidemiologic Studies Depression Scale observations, 3 clinical course types of depressive symptoms were defined. ResultsRemission, fluctuating course, and chronic course of depressive symptoms were seen in 21%, 48%, and 30%, respectively. Slowed gait speed at baseline was associated with a chronic course of depressive symptoms using remission as the reference (odds ratio 0.56, 95% confidence interval 0.41–0.77). Processing speed and vascular risk factors explained this association only for 2%. Specific somatic comorbidity (number of chronic diseases, chronic obstructive pulmonary disease, osteoarthritis) or inflammation influenced the odds ratio. LimitationSome variables were not measured with as much detail as would be possible in a clinical study setting. ConclusionsSlowed gait speed is a robust predictor of chronicity of depressive symptoms in late life, independent of somatic comorbidity and partly in concert with a slowed processing speed. Results suggest that slowed gait speed is an integral part of the depressive syndrome, probably a subtype associated with chronic course, independent of somatic comorbidity.