The Relationship Between Pulse Pressure Trajectories And The Long-term Change In Memory Among Middle-aged And Older Adults

Aim:As the population ages and people live for longer,age-related health problems have attracted growing attention from the whole society.Cognitive impairment is a common condition in older population.It not only seriously endangers the physical and mental health of the elderly,but also places an immense burden on their families and the whole health system.Recently,substantial evidence indicates that subjective memory impairment may be the earliest preclinical phase of dementia.Within this context,identifying potential influence factors associated with memory decline can provide a critical opportunity for early intervention to delay or reverse the onset of dementia.Existing research on the role of pulse pressure（PP）in memory function were limited and the results were inconsistent.To data,few longitudinal studies have investigated the impact of PP trajectories on long-term change in memory among middle-aged and older adults.Hence,we conducted a longitudinal study to investigate patterns of PP and its impact on trajectory of memory overtime,which could provide additional evidence for earlier and effective intervention strategies for ameliorating cognitive deterioration.Methods:Data from the English Longitudinal Study of Ageing（ELSA,2004-2016）,an open database,were analyzed.The baseline survey（Wave 1,W1）was conducted in 2002,then follow-up interviews occur biannually with nurse visits every four years.Up to now,ELSA have collected five follow-up interviews and four nurse visits.Blood pressure was measured by well-trained nurses using Omron HEM-907 monitor.Memory performance was measured with standardized questionnaires.For the purpose of this study,group-based trajectory modeling（GBTM）with four visits of blood pressure（2004-2016）as outcomes was applied to characterize longitudinal patterns of PP over a 12-year period.Then,generalized estimating equation（GEE）models were approached to explore the longitudinal relationship between PP trajectories and four repeated visits of memory.All of the GEE analyses were controlled for the potential confounding variables,involved age,sex,body mass index（BMI）,smoking status,alcohol consumption and antihypertensive medication use.Results:Over a mean of 12 years of follow-up,a total of 2,210 participants aged 50 years or above who had four measures of blood pressure were eligible for the study,including 995（45.0%）males and 1,215（55%）females.Using GBTM,four distinct trajectories in PP were identified and were labeled as low-increasing group（n=652,30.2%）,moderate-increasing group（n=1,065,45.8%）,high-increasing group（n=345,16.2%）and extreme-high stable group（n=148,7.8%）.At baseline,the mean scores of memory across PP trajectory groups were 11.43?3.04、11.28?2.95、10.68?2.95、10.93?3.08,respectively.At the fourth panel study,the scores were 10.64?3.56、10.35?3.58、9.71?3.70、9.80?3.92,respectively.The memory performance appeared a downward trend.The results of GEE models indicated relative to low-increasing group,participants in the high-increasing group had a lower memory score（?=-0.58,95%CI:-1.03,-0.14）.There were no significant differences between the other PP trajectory groups and the reference group（moderate-increasing group:?=-0.05,95%CI:-0.37,0.28;extreme-high stable group:?=-0.21,95%CI:-0.81,0.40）.No significant interactions between PP trajectories and time with memory were identified（?=-0.54～0.14,P=0.102～0.841）.Further joint tests also suggested that the overall interactions between patterns of PP change and time with memory was not significant(joint test:?²_interaction=8.67,df=9,P=0.468).However,the predictive margins of GEE models showed that in relative to those in the low-increasing group,those in the high-increasing and extreme-high stable group maintained a lower memory score and tended to experience a faster rate of decline in memory overtime.Conclusion:Four discrete trajectories of PP were determined,namely,low-increasing,moderate-increasing,high-increasing and extreme-high stable group.Both High PP levels and increasing PP patterns in middle age were risk factors for memory decline.This study emphasizes the importance of the dynamic change of blood pressure overtime and provides the additional evidence that maintaining proper and stable blood pressure levels is beneficial to prevent or alleviate the cognitive decline in midlife.