Trends in Cognitive Function Pre- and Post- Stroke: Finding from the China Health and Retirement Longitudinal Study

Introduction The magnitude of changes in cognitive function after stroke among the Chinese population is not clear. We aimed to learn the trajectories of cognitive function before and after incident stroke among Chinese participants. Methods Data were obtained from a nationally representative study. A total of 13311 Chinese participants aged 45 years or older and without a history of stroke were assessed at baseline between June 2011 and March 2012 and in at least one cognitive test between Wave 2 to Wave 4. Cognitive function was assessed by a global cognition score, which included episodic memory, visuospatial abilities, and executive function. A linear mixed model was developed to explore the repeated measurements. Results During the seven-year follow-up, we observed 610 (4.6%) participants experienced the first stroke. The baseline mean (SD) age was 58.6 (9.2) years. 47.3% of them were male. There was no difference in the baseline cognitive function and decline rate of pre-stroke cognition between stroke survivors and stroke-free participants after adjusting for covariates. Among the stroke survivors, the acute decline was -0.123, -0.169, and -0.135 SD/y in cognitive domains of episodic memory, visuospatial ability, and global cognition, respectively. The executive function did not decline acutely after stroke. In the years following stroke, the decline rate of executive function was 0.056 SD/y faster than the rate before stroke. The decline rate of episodic memory, visuospatial ability, and global cognition did not accelerate after stroke. Conclusion Before stroke onset, the cognitive function of Chinese stroke survivors was similar to that of stroke-free participants. Incident stroke was associated with acute decline in global cognition, episodic memory, and visuospatial abilities, and accelerated decline in orientation, attention, and calculation abilities. The cognitive trajectories revealed by our study highlights the need to care for the cognitive decline among Chinese stroke survivors.