Abstract

Background: Pulmonary function declines with aging impairs the capabilities of oxygen delivery to the brain and may affect on cognitive performance. The  purpose of this study was to examine the relationship between spirometric data, cognitive function and cerebral oxygenation in middle-aged and elderly individuals.

Methods: Subjects who were older than 45 years old were recruited from long-term care facilities. The pulmonary function was measured through forced expiratory volume in 1 second (FEV₁), forced vital capacity (FVC) and peak expiratory flow (PEF). The cognitive function was assessed by the Montreal Cognitive Assessment (MoCA) and Mini-Mental State Examination (MMSE). The cerebral oxygenation status was assessed by the near-infrared spectroscopy (NIRS).

Results: Sixty subjects participated in the study. The cognitive function (MMSE score) was also significantly related to FEV₁ (r = 0.374, p = 0.003), FEV₁/FVC (r = 0.319, p = 0.013), and PEF (r = 0.482, p < 0.001). The MoCA scoreswere significantly related to FEV₁ (r = 0.418, p = 0.001), FEV₁/FVC (r = 0.319, p = 0.013), and PEF (r = 0.508, p < 0.001). Subjects in normal lung function group have significantly higher MMSE scores (24.0 ± 9.1) than those in abnormal  lung function group (17.2 ± 7.2, p = 0.006). No difference in the measurements of cerebral oxygenation was found between normal and abnormal lung  function group (> 0.05).

Conclusion: In this cross-sectional study, the pulmonary function and cognitive function declined with aging. A better pulmonary function was associated with better cognitive function. However, longitudinal studies were required to determine the possible causation between cognition and pulmonary function.