Worse baseline lung function is associated with worse cognition among older black and white adults

Abstract

AbstractBackgroundPrior studies indicate that lung function may be an important risk factor for cognitive impairment and decline, but the body of evidence has largely been restricted to cross‐sectional and single‐time point measurement studies in white populations.MethodsWe studied 1128 black and 1641 white participants, mean age 74 years (SD 3), without prevalent dementia at enrollment in the Health Aging and Body Composition (Health ABC) Study. Participants completed spirometry assessments including Forced Expiratory Volume in 1 second (FEV1) at baseline, years 5, 8, and 10. Digit Symbol Substitution Test (DSST) and Modified Mini‐Mental exam (3MS) were used to assess processing speed and global cognitive function at years 5, 8, 10, and 11. We evaluated the association of baseline and rate of change in lung function in relation to baseline and change in cognitive performance (stratified by race) with mixed linear regression models and adjusting for demographics, comorbid health conditions and health behaviors.ResultsCompared to white participants, black participants had less education, lower socioeconomic status, and were more likely to be current smokers. Baseline mean FEV1 was 2300 ml (SD 551) and 1949 ml (SD 640) in white and black participants. During follow‐up lung function decreased by 207 ml (95%CI 199, 215) and 139 ml (95%CI 130, 148) respectively. In multivariable adjusted analyses, higher baseline lung function was associated with better cognitive test scores. One standard deviation (SD) lower baseline FEV1 was associated with worse DSST scores (by 1.50 (95%CI 0.42,2.73) and 0.60 (95%CI ‐1.0, 2.16) points in whites and blacks respectively, p for interaction = 0.04.) In both black and white participants, there were small but not significant effects of decline in lung function on subsequent cognitive performance and decline.ConclusionWhile the magnitude of the association was stronger in whites, we found worse baseline lung function was associated with worse cognitive function up to 10 years later in both black and white participants. Declines in lung and cognitive function vary by population‐level factors. For interventions, it is important to determine if these associations are biological or socially patterned.