Relationship Between Circadian Rhythm Of Blood Pressure And Memory Function In Patients With The Elderly Hypertensive

Blood pressure fluctuates with the rhythm of 24 hours in healthy people.When people wake up,blood pressure rises from 6:00 a.m.and reaches its first peak at 10:00 a.m.Then it declines gradually and reaches the second peak from 16:00 to 20:00.Its trough appears from 0:00 to 3:00.During the day the blood pressure is at a relatively high level for 14 hours and during the night at a relatively low level for about 10 hours.The curve shape of blood pressure is formed with two peaks and one trough looking like a ladle.During the past decades 24-hour ambulatory blood pressure monitoring(ABPM)has been extensively applied by which we can observe circadian rhythm more easily.According to characters of the fluctuation blood pressure rhythms can be divided into four types:1.Dipper,which defined as a 10-20%fall in nocturnal blood pressure;2.Nondipper,with a nocturnal fall less than 10%;3.Extreme dipper,which with a nocturnal fall greater than 20%;4.Reverse-dipper,as less than 0%at most fall in nocturnal blood pressure.Dipper is the normal circadian rhythm while the others are abnormal ones.In recent years many studies showed that abnormal circardian rhythm could Seriously affect the person's cognitive functions.Memory is the most important part of cognitive process,and the relationship between circadian rhythm of blood pressure in 24 h and memory function in patients with essential hypertension have seldom been reported,This study was designed to investigate the influence of circadian rhythm on memory function of patients with essential hypertension in the elderly,To provide the clinical basis for the rational use of antihypertensive drugs to adjust blood pressure rhythm,and effective prevention of memory dysfunction.Objective:To study the relationship between ambulatory blood pressure circadian rhythm and memory function in elderly primary hypertension patients.Method:1 115 cases were randomly selected from Department of Geriatrics of the Affiliated Hospital of Chengde Medical College during the period from October 2012 to April 2013.All patients with essential hypertension were classified into 4 groups according to circadian rhythm:Dippers,with 30 cases;Nondippers,with 30 cases;Extreme dippers,with 25 cases;Reverse dippers,with 30 cases.Thirty healthy subjects served as control.2 Ambulatory blood pressure monitoring The values of blood pressure were monitored by Japanese AND TM-2430 ambulatory blood pressure monitoring system.All observed parameters contained 24hSBP,24hDBP,24hPP,24hMBP,dSBP,dDBP,dPP,dMBP,nSBP,nDBP,nPP,nMBP,?MBP%.3 Method of evaluating circadian rhythm and grouping?MBP%=(dMBP-nMBP)/dMBP×100%.Dipper,which defined as a 10-20%fall in nocturnal blood pressure;Nondipper,with a nocturnal fall less than 10%;Extreme dipper,which with a nocturnal fall greater than 20%;Reverse-dipper,as less than 0%at most fall in nocturnal blood pressure.4 Memory function determination RBMT-?(Rivermead behavioural memory test second edition)was used to evaluat the memory function.5 The basic situation of collecting subjects,such as name,sex,age,course of hypertension,Level of Education,BMI.6 Laboratory tests:TQ TC,LDL-C,HDL-C,GLU,Cr,UA,BUN were examined.7 SPSS 17.0 was used in all statistical analyses,one-way analysis of variance(ANOVA)and LSD-t test were used to analyze measurement data,Chisquare test was used to analyze enumeration data.There was statistical significance if P<0.05.Results:1 There were no significant differences in sex,age,course of hypertension,Level of Education,BMI in Dippers,Nondippers,Extreme dippers,Reverse dippers and Control group(P>0.05).2 Index of 24-hour blood pressure mornitoring.2.1 There were significant differences on dSBP,dDBP,dPP,dMBP in Dippers,Nondippers,Extreme dippers and Reverse dippers(P<0.05).And there were no significant differences on dSBP in Nondippers and Reverse dippers(P>0.05),there were no significant differences on dDBP in Dippers,Nondippers and Reverse dippers(P>0.05),there were no significant differences on dPP in Dippers and Nondippers(P>0.05),there were no significant differences on dMBP in Dippers,Nondippers and Reverse dippers(P>0.05).2.2 There were significant differences on nSBP,nDBP,nPP,nMBP in Dippers,Nondippers,Extreme dippers and Reverse dippers(P<0.05).And there were no significant differences on nPP in Dippers and Nondippers P?0.05).2.3 There were significant differences on ? MBP%in Dippers,Nondippers,Extreme dippers and Reverse dippers(P<0.05).2.4 There were no significant differences on 24hSBP,24hDBP,24hPP,24hMBP in Dippers,Nondippers,Extreme dippers and Reverse dippers(P>0.05).3 There were no significant differences on TG,TC,LDL-C,HDL-C,GLU,Cr,UA and BUN in Dippers,Nondippers,Extreme dippers and Reverse dippers(P>0.05).4 The levels of Memory scores in Dippers,Nondippers,Extreme dippers and Reverse dippers.4.1 Scores of RBMT-? in hypertension group were significantly lower than that of control(10.0±0.8,9.4±1.1,8.6±1.5,8.9±1.1 vs contro110.5±0.9,P<0.05).4.2 Scores of RBMT-? in nondippers,extreme dippers and reverse dippers hypertensives were significantly lower than that of dipper hypertensives(nondippers:9.4± 1.1 vs extreme dippers:8.9 ± 1.1 vs reverse dippers:8.6 ±1.5 vs dippers:10.0 ±0.8,all P<0.05).The scores in extreme dippers and reverse dippers hypertensives were also lower than that of nondippers hypertensives(extreme dippers:8.9 ±1.1 vs reverse dippers:8.6±1.5 vs nondippers:9.4± 1.1,all P<0.05)?there was no significant difference between extreme dippers and reverse dippers hypertensives(extreme dippers:8.9± 1.1 vs reverse dippers:8.6± 1.5,P>0.05).4.3 Scores of RBMT-?in hypertension group were significantly lower than that of control in name score,date score and operation score(P<0.05).Scores of RBMT-? in nondippers were significantly lower than that of dippers in date score and rout score(P<0.05).Scores of RBMT-?I in extreme dippers and reverse dippers were significantly lower than that of dippers and nondippers in name score,rout score,operation score,face score and picture score(P<0.05).There was no significant difference between extreme dippers and reverse dippers in each component score of RBMT-?(P>0.05).Conclusion:1 Hypertension have an important influence on memory functionn in older people.2 The abnormal blood pressure rhythms are important factors influencing the memory function in elderly patients with primary hypertension.3 There were different effects on the degree of memory function for different circadian rhythm of senile primary hypertension.dipper<non-dipper<super-dipper =reverse-dipper.