Pulmonary Function in Midlife as a Predictor of Later-Life Cognition: The Coronary Artery Risk Development in Adults (CARDIA) Study.

BACKGROUND

Studies found associations between pulmonary function (PF) and cognition, but these are limited by mostly cross-sectional design and a single measure of PF (typically forced expiratory volume in 1 second [FEV1]). Our objective was to prospectively analyze the association of repeatedly measured PF with cognition.

METHODS

We studied 3 499 participants in the Coronary Artery Risk Development in Young Adults cohort with cognition measured at year 25 (Y25) and Y30, and PF (FEV1 and forced vital capacity [FVC], reflecting better PF) measured up to 6 times from Y0 to Y20. Cognition was measured via Stroop test, Rey-Auditory Verbal Learning Test [RAVLT], and digit symbol substitution test [DSST], which capture executive function, verbal learning and memory, and attention and psychomotor speed, respectively; lower Stroop, and higher RAVLT and DSST scores indicate better cognition. We modeled linear, cross-sectional associations between cognition and PF at Y30 (mean age 55), and mixed models to examine associations between cognition at Y25-Y30 and longitudinal PF (both annual rate of change, and cumulative PF from Y0 to Y20).

RESULTS

At Y30, FEV1 and FVC were cross-sectionally associated with all 3 measures of cognition (β = 0.08-0.12, p < .01-.02). Annual change from peak FEV1/FVC ratio was associated with Stroop and DSST (β = 18.06, 95% CI = 7.71-28.40; β = 10.30, 95% CI = 0.26-20.34, respectively), but not RAVLT. Cumulative FEV1 and FVC were associated with Stroop and DSST (β = 0.07-0.12, p < .01-.02), but only cumulative FEV1 was associated with RAVLT (β = 0.07, 95% CI = 0.00-0.14).

CONCLUSIONS

We identified prospective associations between measures of PF and cognition even at middle ages, adding evidence of a prospective association between reduced PF and cognitive decline.