Association of Lung Function with Cognitive Decline and Incident Dementia in the Atherosclerosis Risk in Communities Study.

We examined the associations between lung function and incident dementia and cognitive decline in 12,688 participants of the ARIC study who provided lung function measurements in 1990-1992. Cognitive tests were administered up to seven times, and dementia was ascertained through 2019. We used shared parameter models to jointly model proportional hazard models and linear mixed-effect models to estimate lung function-associated dementia rate and cognitive change, respectively. Higher forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) were associated with reduced dementia rate (n=2452 developed dementia); hazard ratios per 1L higher FEV1 and FVC were 0.79 (95%CI: 0.71-0.89) and 0.81 (95%CI: 0.74-0.89), respectively. Each 1L higher FEV1 and FVC was associated with 0.08 (95%CI: 0.05-0.12) SD and 0.05 (95%CI: 0.02-0.07) SD attenuation of 30-year cognitive decline, respectively. One percent higher FEV1/FVC was associated with 0.008 (95% CI: 0.004-0.012) SD less cognitive decline. We observed statistical interaction between FEV1 and FVC, suggesting that cognitive declines depended on values of specific FEV1 and FVC (as compared to FEV1, FVC, or FEV1/FVC% models that suggested linear incremental associations). Our findings may have important implications for reducing burden of cognitive decline that is attributable to environmental exposures and associated lung function impairment.