Changes in Plant-Based Dietary Quality and Subsequent Risk of Cognitive Impairment Among Older Chinese Adults: a National Community-Based Cohort Study

Abstract

BackgroundIt is unclear how changes in plant-based dietary quality are linked to the subsequent risk of cognitive impairment. ObjectivesThis study aims to evaluate this relationship using data from the Chinese Longitudinal Healthy Longevity Survey. MethodsA total of 6662 participants free of cognitive impairment in 2008 were included and followed ≤2018. Plant-based dietary quality was assessed by 3 indices: overall plant-based diet index (PDI), healthful PDI (hPDI), and unhealthful PDI (uPDI). Changes in plant-based diet quality from 2008 to 2011 were classified into quintiles. In addition, we assessed incident cognitive impairment (from 2011 to 2018) by using the Mini-Mental State Examination. Cox proportional-hazards models were performed. ResultsWe recorded 1571 incident cases of cognitive impairment during a median of 10 y of follow-up. Compared with participants whose plant-based diet had no change or was relatively stable over 3 y, the full-adjusted hazard ratios (HRs) with 95% confidence intervals (CI) for cognitive impairment were 0.77 (0.64, 0.93), 0.72 (0.60, 0.86), and 1.50 (1.27, 1.77) among participants with a large increase in PDI, hPDI, and uPDI, respectively. The HRs with 95% CI were 1.22 (1.02, 1.44), 1.30 (1.11, 1.54), and 0.80 (0.67, 0.96) among participants with a large decrease in PDI, hPDI, and uPDI, respectively. Every 10-point increase in PDI and hPDI was associated with a 26% and 30% lower risk of cognitive impairment, whereas every 10-point increase in uPDI was associated with a 36% higher risk. ConclusionsOlder adults with increased adherence to an overall plant-based diet and a healthful plant-based diet over 3 y have a lower risk of cognitive impairment, whereas those with increased adherence to an unhealthy plant-based diet had a higher risk of cognitive impairment.