The presence of emphysema on chest imaging and mid-life cognition

BACKGROUND: Airflow obstruction is associated with cognitive dysfunction but studies have not assessed how emphysema, a structural phenotype of lung disease, might be associated with cognitive function independent from pulmonary function measured by spirometry. We aimed to determine the relationship between the presence of visually detectable emphysema on chest computed tomography (CT) imaging and cognitive function. METHODS: We examined 2491 participants, mean age of 50 years, from the Coronary Artery Risk Development in Young Adults study who were assessed for the presence of emphysema on chest CT imaging and had cognitive function measured 5 years later with a battery of six cognitive tests. RESULTS: Of those assessed, 172 (7%) had emphysema. After adjusting for age, sex, height, study centre, race, body mass index, education and smoking, visual emphysema was significantly associated with worse performance on most cognitive tests. Compared to those without emphysema, participants with emphysema performed worse on cognitive testing: 0.39 sd units lower (95% CI −0.53– −0.25) on the Montreal Cognitive Assessment, 0.27 sd units lower (95% CI −0.42– −0.12) on the Rey Auditory Verbal Learning Test, 0.29 sd units lower (95% CI −0.43– −0.14) on the Digit Symbol Substitution Test and 0.25 sd units lower (95% CI −0.42– −0.09) on letter fluency. Further adjustment for forced expiratory volume in 1 s (FEV(1)), peak FEV(1) and annualised FEV(1) decline did not attenuate these associations. CONCLUSIONS: The presence of emphysema on chest CT is associated with worse cognitive function, independent of airflow obstruction. These data suggest that emphysema may be a novel risk factor for cognitive impairment.