A Study On The Association Between Serum Acid And Essential Hypertension In Country

PrefaceEssential hypertension was a common cardiovascular disease.High blood pressure(HBP) can lead to other cerebrovascular disease,Over 25%people around the world suffer from the EHT.The national nutrition and health status investigation show that the HBP prevalence of adult was 18.8%,raising 31%than 1991,increasing year by year.EHT was becoming one of the principal diseases which jeopardizing the human health.In 1879,Frederick Mohamed introduced the association between serum uric acid(SUA) and EHT first,HBP usually be with hyperuricacidemia(HUA).A large of experiments and clinical trial show that SUA was related to EHT in epidemiology, nosogeneswas and treatment closely.Its difficult to discriminate whether SUA was the causative agent of EHT or it was the larvate pathomarker,because SUA was mix up with larvate renal inadequacy and anomal-metabolwasm,lead to HBP alone or interaction.The level of SUA increasing was concemed with high protein diet.The studys formerly concern about the SUA in Urban dweller,nowadays,living standard of country are raising.For studying the association between serum acid and Essential hypertension in country where EHT incidence rate was higher,our disscussion based on a large number of EHT patients and the control in order to put forward pathogenic research evidence on EHT.Subjects and Methods1.The selection method and standard of study populationUsing the method of clustering multistage sampling method,5 countrysides were randomly selected in ZhanWu County,LiaoNing Province,and then randomly selected 2 villages in 5 countrysides.All the people above 18 years old in the selected 10 villages were investigated.5000 people have been investigated.Other conditions being able to induce serum acid increase or decrease unrealted to body acid stores such as hepatopathy,renopathy and essential hyperuricacidemia were excluded.And secondary hypertension was excluded also.Rancom select 300 EHT patients in different levels average and 200 controls by SPSS 12.0.Utility number of samples was 497,the male was 192,the female was 305,age range was from 30 to 83 years old.2.The contents of investigation(1) Questionnaires were filled by means of inquiring and measurement in sites. The contents of survey included:general characterwastics,alcohol intake,smoking habits,previous disease history and so on,measurement of the blood pressure,body height and weight.(2) Five milliliters blood samples were drawn after an ovemight fast.After centrifugation,the serum fraction was removed and frozen in aliquots at -78℃until assayed.The serum was used for the measure of hematological biochemwastry assay.3.Diagnosis standard and chemical measurementsThe diagnosis standard of EHT:According to 1999 WHO-WASH guidelines for the management of hypertension,hypertension was defined as a systolic blood pressure(SBP)≥140mmHg and/or a diastolic blood pressure(DBP≥90mmHg.The grading standard of EHT.SBP＜139mmHg and/or DBP＜89mmHg;the first grade.140mmHg≤SBP≤159mmHg and/or 90mmHg≤DBP≤99mmHg;the second grade.160mmHg≤SBP≤179 mmHg and/or 100mmHg≤DBP≤109mmHg the thied grade.SBP≥180mmHg and/or DBP≥110mmHg.The measurement of blood pressure should be carried out according to the unified standard under standard conditions.Serum acid was measured by automatic biochemwastry analyzer 7600-110,range of normal values was 143μmol/L～416μmol/L.Cholesterol(CHOL),triglyceride(TG), high density lipoprotein(HDL),low density lipoprotein(LDL) were measured by automatic biochemwastry analyzer 7150(HITA-CHI),the blood-fasting sugar(BFS) was measured by blood suger nanlyzer(Johnxon & johnxon,America).4.Statistical methodsA database was created by SPSS after quality examination of data.Method of analysis includesχ~2 test,variance analysis,logistic regression.The soft ware used was SPSS 12.0.Statistics significance level wasα=0.05. Results1.The distribution character of SUA between the case and the control(1) The compare of SUA between the case and the controlConcentration of SUA had a significant statistical difference(p＜0.01) between the high EHT and the control,the EHT group was higher than that of the control group. And Concentration of SUA also had a significant statistical diffemect(p＜0.01) between the high SBP,DBP and their control,the high SBP,DBP groups were higher than that of the control groups.(2) The level of SUA among different grades in EHT patients.In different grades,the level of SUA was rising with grade(P＜0.01).There was significant statistical difference among different grades in EHT patients(P＜0.01).There were also statistical difference between every two grades(P＜0.05).(3) The level of SUA among different age groups in EHT patients and control.In different grades,the level of SUA was rising with age.Except 30-39 years old and 60-69 years old,there were significant statistical difference between EHT patients and control in the same age group(P＜0.01),the EHT group was higher than that of the control group.Compare SUA level among different age groups in EHT group or in control,there were both significant statistical difference.Except 30-39 years old & 40-49 years old,40-49 years old & 50-59 years old,there were significant statistical difference between every two grades(P＜0.01) in EHT patients.(4) The level of SUA between gender in EHT patients and control.There was significant statistical difference between EHT patients and control in different gender(P＜0.01),the SUA level in EHT patients was higher than that in control. There was also significant statistical difference between gender in EHT patients or in control(P＜0.01),the SUA level in male was higher than female in every group.2.Monovariate analysis on the related risk factors of blood pressure(1) Monovariate analysis on the related risk factors of EHT. The analysis show that there was statistical difference(P＜0.05) in the distribution of SUA,BMI,TG,blood sugar between EHT group and healthy control.Compared with the first quarter level of SUA,the third and the forth quarter level of SUA were risk factors of EHT,OR=2.72(95%CI:1.57～4.73),OR=3.50(95%CI:1.98～6.19),respctively. Female,BMI＞25,high CHOL,high TG;low HDL,high blood sugar,drinking were risk factors of EHT(OR＞1).(2) Monovariate analysis on the related risk factors of high SBP.The analysis show that there was statistical difference(P＜0.05) in the distribution of SUA,BMI,TG,blood sugar between high SBP group and healthy control.Compared with the first quarter level of SUA,the second,the third and the forth quarter level of SUA were risk factors of high SBP,OR=1.84(95%CI:1.08～3.15),OR=2.78(95%CI: 1.61～4.84),OR=3.74(95%CI:2.13～6.57),respctively.Female,BMI≥25,high CHOL, high TG,low HDL,high LDL,high blood sugar,drinking were risk factors of high SBP(OR＞1).(3) Monovariate analysis on the related risk factors of high DBP.The analysis show that there was statistical difference(P＜0.05) in the distribution of SUA,BMI,TG,drinking between high DBP group and healthy control.Compared with the first quarter level of SUA,the second,the third and the forth quarter level of SUA were risk factors of high DBP,OR=1.86(95%CI:1.08～3.20),OR=2.29(95%CI: 1.33～3.96),OR=3.01(95%CI:1.73～5.24),respctively.BMI≥25,high TG,low HDL, high LDL,high blood sugar,drinking were risk factors of high DBP(OR＞1).3.Multivariate analysis concerned with hypertensionMultivariate analysis was conducted on all the factors and age.We used Logistic regression analysis consitute model of EHT,high SBP and high DBP model.(1) Model of EHTThe model showed that compared with the first quarter level of SUA,the third and the forth quarter level of SUA were risk factors of EHT(OR=1.535,95%CI: 1.264～1.865 ),high CHOL was the risk factor of EHT.(2) Model of high SBPThe model showed that compared with the first quarter level of SUA,the third and the forth quarter level of SUA were risk factors of high SBP(OR=1.403,95%CI: 1.158～1.699),high CHOL,BMI＞25,drinking and increment of age were the risk factors of high SBP.(3) Model of high DBPThe model showed that compared with the first quarter level of SUA,the second, the third and the forth quarter level of SUA were risk factors of high DBP(OR=1.470, 95%CI:1.212～1.783 ),high CHOL,BMI＞25 and drinking were the risk factors of high DBP.DisscussionAs we know that a number of factors could make blood pressure increasing,but there can not completely explain the cause of EHT,which showed that there were some unidentified risk factors related to EHT.SUA was the metabolite of nucleic Acid.Over the past many consider the high uric acid was a accompanied phenomenon of high blood pressure,a kind of purine metabolites without physiological significance(except for gout quality).In recent years,serum uric acid(SUA) was no longer just the diagnosis of gout and renal function reflects indicators,its relation to high blood pressure,cardiovascular and cerebrovascular diseases have been more and more attention.A large number of epidemiological and clinical trials confirmed the increased levels of serum uric acid are closely related to hypertension and other cardiovascular and cerebrovascular diseases. A person with high serum uric acid level will happen hypertension often.1.The distribution of Serum uric acid levels in different EHT grades.Cannon found that level of serum uric acid in hypertension patients often higher than normal,higher blood pressure grade higher serum uric acid level.Our result showed that concentration of SUA had a significant statistical difference between the high EHT and the control,the EHT group was higher than that of the control group. And Concentration of SUA also had a significant statistical differnect between the high SBP,DBP and their control,the high SBP,DBP groups were higher than that of the control groups.The mechanism why the level of SUAin EHT patients were higher was unknown.Edware think the level of SUA were positively correlated with increased vascular resistance in EHT patients,also the early performance of impaired renal function.In different EHT grades,the level of SUA was rising with grade.The reason might be HBP lead to kidney micrangium affection aggravate,then the level of SUA increasing.So the level of Serum uric acid was ralate to severity of EHT.2.The levelof Serum uric acid levels in different gender and different age of EHT patients.Many studies consider,the level of serum uric acid in elderly and men were higher. The study found that the level of serum uric acid in EHT group increased with age. SUA is the end products of purine metabolism,the function of renal breakdown in elder, so the level of SUA increasing.Also male serum uric acid level higher than that of women.There were significant statistical difference between EHT patients and control in different gender,the SUA level in EHT patients was higher than that in control. Mainly caused by the gender hormone,estrogen also can promote excretion of uric acid, so the level of SUA in postmenopausal women were higher than pre-menopausal female.3.High SUA was the independengt risk factor to EHT,SBP and DBP.A large number of epidemiological studies have shown that the level of serum uric acid was the strongest independent prediction factor and significant risk factors for EHT.After classifying the level of SUA into four quarters,we found that the third,the forth quarter of serum uric acid were risk factors to EHT,first quarter was control.The higher concentrations of SUA,the risker of EHT.Adjusted other risk factors(including the metabolic syndrome related factors)by logistic regression analysis,there correlation was still existence.The level of SUA incerase a quarter,the risk with EHT increase 0.535 times.Single-factor analysis found that,high concentration of SUA also was the risk of high SBP and high DBP.With the serum uric acid levels increased,the risk of SUA and high SBP was higher than and DBP.But adjusted other risk factors(including the metabolic syndrome related factors) by logistic regression analysis,there correlation between SUA and DBP was higher than SBP.Although this study was a large sample population-based study,but the target population was rural population,therefore the Extrapolation of conclusions was limited; Some clinical epidemiological data showed there was a continuing relationship between SUA and EHT,especially in young patients.This study was a cross-sectional survey,just could prompt the causal association of these two in interpretation,it was recommended for long-term follow-up study to observe the association;The measure of SUA has a large biological and analytical variablity though we wtrictly contrlooed the measure.In order to testify the association between the level of SUA and EHT, follow-up prospective study should be used with continuously measure of reliable indicator of SUA.ConclusionHigh SUA was correlated with EHT closly.After adjusting other risk factors(including the metabolic syndrome related factors),SUA was still the independent risk factor to EHT;Comparing with SBP,SUA was correlated more closely with DBP.