Poor lung function accelerates cognitive decline in middle-aged and older adults: Evidence from the English...

Previous studies have linked lung function to cognitive performance. However, it is not clear whether baseline lung function has an effect on the trajectory of cognitive decline during normal aging. This study aimed to examine the association of baseline lung function with long-term changes in cognition among the middle-aged and older adults.

Lung function as indicated by forced expiratory volume 1 s (FEV1) and forced vital capacity (FVC), was measured at the baseline examination. Cognition, including memory, time orientation, executive function and processing speed, were tested four times over six years. Generalized estimating equation (GEE) models were used to test the associations between baseline lung function and four visits of cognition in 6080 participants aged 50 years or over from the English Longitudinal Study of Ageing (ELSA).

Compared to participants with higher lung function, those who had lower lung function at baseline experienced a faster rate of decline in memory (joint test: χ²_interaction = 12.07, df = 3, P = 0.007 for FVC), time orientation (joint test: χ²_interaction = 9.49, df = 3, P = 0.023 for FVC) and executive function (joint test: χ²_interaction = 9.13, df = 3, P = 0.028 for FEV1 and joint test: χ²_interaction = 12.76, df = 3, P = 0.005 for FVC). No association was found between baseline lung function and the rate of decline in processing speed (joint test: χ²_interaction = 1.29, df = 3, P=0.733 for FEV1 and joint test: χ²_interaction = 2.35, df = 3, P = 0.503 for FVC).

Poor lung function at baseline predicted a faster rate of cognitive decline in memory, time orientation and executive function. The mechanism for this association deserves further investigation.