The association between injurious falls and older adults' cognitive function: the role of depressive mood and physical performance.

BACKGROUND The impact of falls on cognitive function is unclear. We explored whether injurious falls are associated with cognitive decline in older adults, and evaluated the role of changes in psychological and physical health as mediators of such association. METHODS This prospective study involved 2,267 community-dwelling participants in the Swedish National study on Aging and Care in Kungsholmen (≥60 years). Data on injurious falls (i.e., falls requiring medical attention) during each 3-year time interval of follow-up were obtained from national registers. Assessment of cognitive function (Mini-Mental State Examination[MMSE]), depressive mood (Montgomery-Asberg Depression Rating Scale), and physical performance (walking speed) were carried out every 3 or 6 years over a 12-year follow-up. The association between falls and cognition was estimated through linear mixed effects models, and the mediating role of changes in depressive mood and physical performance was tested using mediation analysis. RESULTS After adjusting for potential confounders, individuals who experienced injurious falls had a greater annual decline in MMSE in the subsequent time interval (β=-1.49, 95%CI:-1.84;-1.13), than those who did not. The association increased with the occurrence of ≥2 falls (β=-2.13, 95%CI:-2.70;-1.56). Worsening of walking speed and depressive mood explained around 26% and 8%, respectively, of the association between falls and cognitive decline. CONCLUSIONS Injurious falls are associated with greater cognitive decline, and this association is partly mediated by worsening of physical performance and, in a lesser extent, of depressive mood. These findings suggest that physical deficits and low mood are potential therapeutic targets for mitigating the association between falls and cognitive decline.