A Study On The Relationship Between Serum Adiponectin Levels And Stroke In Rural Areas Of Zhan Wu County In LiaoNing Province

PrefaceStroke is a major disease in our country,which seriously endangering the lives and health of middle-aged and elderly.It is bringing a heavy social and economic burden with fatality and disability rate.So a lot of areas become focus on the study of controlling the occurrence and development of stroke.Atherosclerosis is the pathological basis of stroke.Adiponectin(APN)is a collagen-like plasma protein specifically synthesized in adipose tissue.There is evidence that APN plays an important role in pathogenesis of atherosclerosis,thereby affecting the occurrence and development of stroke.Although much attentions are paid to the studies about the relationship between APN and stroke,most studies are limited to atherosclerosis or coronary heart disease. Results of the relationship between APN levels and stroke,reported at home and abroad, are still different,with less domestic research and focusing on hospital patient or out-patient.Choose rural areas of ZhangWu County with high prevalence of hypertension in LiaoNing province to study the prevalence of Stroke and to carry out case-control study with simple random sampling from stroke patients and healthy population.Measure serum APN,then analyze relationship between APN and stroke with multivariate factors analysis to provide a basis for etiology research of stroke, prediction of stroke and evaluation of their prognosis.Subjects and Methods1.The selection method of study subjectsUsing the method of clustering multistage sampling method,6 countrysides were randomly selected in ZhanWu County,LiaoNing Province.All the people above 18 years old in the selected 11 villages were investigated.5208 people have been investigated including general characteristics and risk factors of stroke.229 cases of stroke patients were found in specific diagnosis.Then using simple random sampling method,selected 121 cases of stroke patients(case group:male/female 67/54,mean age 61.96±10.188 years) and 121 healthy persons as control with simile sex proportion and mean age(control group:male/female 69/52,mean age 60.48±12.909years).2.The contents of investigation and measurement indicatorsQuestionnaires were filled by means of inquiring and measurement in sites.The contents of survey included:general characteristics,smoking habits,alcohol intake and so on.Measure blood pressure,body height and weight,et al.Five milliliters blood samples were drawn after an overnight fast.After centrifugation,the serum fraction was removed and frozen in aliquots until assayed.3.Diagnosis standard and measurement methods(1)Diagnosis standard of strokeCases were diagnosed by "all types of cerebral vascular disease diagnosis" adopted by the Fourth National Cerebrovascular Disease Academic Meeting in 1995. Previous stroke needed county hospital diagnosis.(2)Measurement methods of blood pressure and serum indicatorsBlood pressure were measured according to the unified standard.Serum levels of APN were measured by Bio-Rad Model 550 Microplate Reader(ELISA).Triglyceride (TG),total cholesterol(TC),high density lipoprotein(H-DL),low density lipoprotein (LDL) were measured by automatic biochemistry analyzer 7150(HITACHI,Japan). Blood sugar were measured by blood sugar analyzer(Johnson＆Johnson,America).4.Statistical methodsA database was created by SPSS after quality examination of data.Student's t-test and analysis of variance were used to assess differences between groups for continuous variables.X~2 test was used to assess differences between groups for categorical variables.Pearson correlations were used for correlation analysis.Multiple linear regression and Multivariate unconditional Logistic analysis were used for multivariate factors analysis.α=0.05. Results1.The comparison of APN levels between case group and control group(1) The comparison of APN levels between case group and control groupResults showed that APN levels were different significantly(P＜0.05).APN level was lower in case group than in control group(7.414±5.595mg/Lvs9.471±5.601mg/L).(2)Further comparison of APN levels between case group and control group according to whether or not have hypertensionAccording to whether or not have hypertension,further analysis showed that APN level was significantly lower in case group without hypertension and case group with hypertension than in control group without hypertension(P＜0.05);and APN level was significantly lower in case group without hypertension than in control group with hypertension and case group with hypertension(P＜0.05).2.Analysis on the related risk factors of Stroke(l)Monovariate analysis on the related risk factors of StrokeThere was no statistical difference of drinking,serum TG,serum HDL,blood sugar between case group and control group(P＞0.05).There was statistical difference of smoking,serum APN,BMI,SBP,DBP,serum TC,serum LDL between case group and control group(P＜0.05).(2)Multivariate unconditional Logistic analysis on the related risk factors of StrokeOn the basis of Monovariate analysis,Multivariate analysis was conducted on factors of smoking,serum APN,BMI,SBP,DBP,serum TC,serum LDL.We used unconditional Logistic regression analysis constitute model of Stroke.Serum APN, SBP enter model.The possibility of suffering from stroke with lower adiponectin level is 4.019 times with normal level(APN:OR=4.019,95%CI:2.092-7.722) and the possibility of suffering from stroke with Systolic hypertension is 3.864 times with normal blood pressure(SBP:OR=3.864,95%CI:2.106-7.087).3.Analysis on the related factors of Serum APN level (1) Analysis of correlation on the related factors of Serum APN levelIn control group,only BMI is negatively related to Serum APN level(P＜0.05).In case group,BMI is negatively related to Serum APN level(P＜0.05),serum HDL,SBP and DBP are positively related to Serum APN level(P＜0.05).(2) Multivariate linear analysis on the related factors of Serum APN levelIn control group,multivariate analysis was conducted on all factors;in case group, multivariate analysis was conducted on factors of BMI,serum HDL,SBP,DBP with serum APN level as dependent variable.We used multiple linear regression analysis to constitute model of APN.In control group,only BMI entered model (B=-0.301,B95%CI:-0.584～-0.019).In case group,serum HDL(HDL:B=2.749, B95%CI:0.030～5.468) and SBP entered model(SBP:B=0.053,B95%CI:0.023～0.084).DiscussionWith people's living standard improving and lifestyle changing in our country,the incidence of stroke is increasing and has become the largest disability and second largest killer disease.So a lot of areas become focus on the study of controlling the occurrence and development of stroke.Moreover,Atherosclerosis,especially the carotid atherosclerosis is closely related to stroke.APN is a hormone secreted by adipocytes with anti-arteriosclerotic properties.Level of APN in the blood is high.It can get through the blood-brain barrier and participate in sugar and fat metabolism. However,the relationship between APN levels and stroke is inconclusive.Therefore, this study discussed it from the serological and epidemiological aspects in order to provide solid evidence for the relationship between APN levels and stroke in rural areas.1.The comparison of APN levels between case group and control groupAs a new type of fat-specific protein,APN can regulate the development and progression of atherosclerosis and can regulate Endothelial function,glucose and lipid metabolism et al.At present,people pay more attention on the role of APN in cardiovascular disease.This study showed that low serum levels of APN were associated with the presence of stroke,as other research results. 2.Risk factors of strokeThis study suggested that the decline of APN levels probably is a risk factor of stroke,that is to say APN possibly is a independent protective factor.Mainly because APN can inhibit inflammatory response,inhibit formation of foam cells and regulate proliferation and migration of smooth muscle cell in the process of AS.In this study,results suggested that Systolic hypertension possibly is a independent risk factor,as most research results.In the process of promoting atherosclerosis, Systolic hypertension mostly cause blood capillary rupture in thickening inner membrane and within atherosclerotic plaque.Then cause Vessel wall hemorrhage, obliteration and thrombosis.So it is easy to cause elderly cerebral arterial thrombosis. Mean age of all the objects was 61.19 years old,so the effect of Systolic hypertension was more obvious.3.Related factors of Serum APN levelAs a hormone secreted by adipocytes,APN is closely related to BMI(index of obesity).My study found that serum APN had significant and negative correlation with BMI in control group,indicating that body-fat can affect serum APN level.Some researches found that plasma concentration was significantly lower in obese than non-obese persons,showing that the expression of APN may be inhibited with negative feedback in obese.This study only found that serum APN levels had independent positive correlation with serum HDL in stroke patients.That was to say serum APN levels were positively related to protective blood-fat compositions.This explained that,in part,serum APN had protective effect on atherosclerosis.Probably because HDL could increase expression and secretion of APN mRNA.Up to now,the correlation between APN and stroke hasn't been approved and mechanism is not clear.This study found that,in stroke patients,SBP remained positively related to APN levels after adjusting other factors.It may be because too high blood pressure cause some organ damages with coexistence of hypertension and stroke and then damages trigger a negative regulatory response.Also it may be because of impaired renal function and decline of protein clearance rate,so APN increase. However,this study did't detect indicators of renal function,therefore needs to be further studied. ConclusionSerum APN level was significantly lower in case group than in control group. According to whether or not have hypertension,further analysis suggested that APN level of stroke patients was significantly lower in subjects with normal blood pressure and that APN level of patients with hypertension was significantly higher in stroke patients.Multivariate analysis suggested that the decline of APN level and Systolic hypertension probably were risk factors of stroke and that BMI,HDL and SBP may affect serum APN levels,to control the occurrence and development of stroke.