Association of pulmonary function with cognitive decline in older adults: a nationwide longitudinal study in China.

Abstract

This study aimed to examine whether pulmonary function and cognition are independently associated at multiple time points. We included 8264 participants (49.9% women) aged 50-94 years at baseline from the China Health and Retirement Longitudinal Study in our analysis. Participants were enrolled in 2011 and followed up in 2013 and 2015. Cognitive function was assessed through a face-to-face interview in each survey. Pulmonary function was assessed via peak expiratory flow. Pulmonary function and cognitive function decreased significantly with age in both genders. Individuals in quintile 5 of pulmonary function had a relative increase in immediate memory (β (95% CI): 0.19 (0.09, 0.30)) and delayed memory (0.16 (0.04, 0.28)) during follow-up compared with those in quintile 1. In the repeated-measures analysis, each standard deviation increment of pulmonary function was associated with a 0.44 (95% CI: 0.34, 0.53), 0.12 (0.09, 0.15), 0.12 (0.08, 0.16), 0.08 (0.06, 0.11), and 0.10 (0.07, 0.14) higher increase in global cognitive score, immediate memory, delayed memory, orientation and subtraction calculation, respectively. The inverse association between pulmonary function and cognitive decline during follow-up was more evident in women (P for interaction=0.0333), low educated individuals (P for interaction=0.0002), or never smokers (P for interaction=0.0412). In conclusion, higher baseline pulmonary function was independently associated with a lower rate of cognitive decline in older adults. The positive association between pulmonary function and cognition was stronger in women, lower educated individuals, or never smokers.