Association of pulmonary function with cognitive trajectories and structural brain differences: A population‐based cohort study

Abstract

AbstractBackgroundThe relation of poor pulmonary function (PF) to cognitive trajectories and the mechanisms behind the relation remains unclear. We aimed to investigate the association of poor PF with cognitive decline in different domains and structural brain volumes.MethodWithin Rush Memory and Aging Project, 1377 dementia‐free subjects were followed up to 21 years. PF was assessed with a composite score (tertiled as the lowest, middle, and highest) based on peak expiratory flow, forced expiratory volume in 1 second, and forced vital capacity measured at baseline. Episodic memory, semantic memory, working memory, visuospatial ability, and perceptual speed were assessed annually constructed from 19 cognitive tests. A sub‐sample of the participants (n=373) underwent brain magnetic resonance imaging (MRI), and total, regional brain (white matter, gray matter) and white matter hyperintensities volumes were assessed. Data were analyzed using linear mixed‐effect models and linear regression models.ResultAt baseline, the PF score was ranged from ‐2.36 to 3.47. In multi‐adjusted mixed‐effect model, compared with the highest PF, the lowest PF was related to decline in global cognition (β=‐0.039, 95% CI: ‐0.054 to ‐0.024), episodic memory (β= ‐0.053, 95% CI: ‐0.072 to ‐0.033), semantic memory (β= ‐0.032, 95% CI: ‐0.048 to ‐0.015), working memory (β= ‐0.028, 95%CI: ‐0.041 to ‐0.014), visuospatial ability (β= ‐0.027, 95% CI: ‐0.042 to ‐0.013), and perceptual speed (β= ‐0.038, 95% CI: ‐0.053 to ‐0.022). In MRI data analysis, the lowest PF was associated with smaller volumes of total brain (β= ‐29.61, 95% CI: ‐45.25 to ‐13.98), white matter (β= ‐12.62, 95% CI: ‐23.56 to ‐1.68), and gray matter (β= ‐16.95, 95% CI: ‐28.93 to ‐4.96), but greater white matter hyperintensities (β= 0.214, 95% CI: 0.094 to 0.334), compared to the highest PF.ConclusionLow PF accelerates cognitive decline in global cognition, episodic memory, working memory, semantic memory, visuospatial ability and perceptual speed. Neurodegeneration and vascular lesions in the brain may underlie the association of PF with cognitive decline.