Associations of changes in late-life blood pressure with cognitive impairment among older population in China.

BACKGROUND: The cognitive impact of changes in late-life blood pressure is less clear. We aimed to investigate the association between late-life blood pressure changing pattern and risk of cognitive impairment. METHODS: Using data from the community-based Chinese Longitudinal Healthy Longevity Survey, change in systolic (SBP) or diastolic (DBP) blood pressure was calculated as the difference between follow-up and baseline, cognitive impairment was defined based on both the Mini-Mental State Examination and education level. The generalized additive model with penalized spline and multivariate logistic regression model were used, respectively, to examine the associations between continuous and categorized blood pressure changes with cognitive impairment at the follow-up wave. RESULTS: A total of 8493 Chinese elderly without cognitive impairment were included, with mean (standard deviation) age 80.6 (10.7) years. U-shaped associations between late-life blood pressure changes and risk of cognitive impairment were found, with only stable optimal blood pressure related to the lowest risk. For participants with baseline SBP around 130-150 mmHg, the adjusted odds ratio was 1.48 (1.13-1.93) for increasing follow-up SBP (> 150 mmHg), 1.28 (1.02-1.61) for decreasing follow-up SBP (< 130 mmHg), compared to stable follow-up SBP (130-150 mmHg). For participants with relative lower baseline DBP (< 80 mmHg), increasing their DBP to 80-90 mmHg during follow-up was associated with lower cognitive impairment risk (0.73 (0.58-0.93)), compared to steady low follow-up DBP (< 80 mmHg). Sex-specific analysis suggested that men were more vulnerable in term of SBP change. CONCLUSIONS: Adhering to a stable optimal level of blood pressure in late-life is related to lower risk of cognitive impairment in Chinese elderly.