Study On Association Between BDNFrs6265Gene Polymorphism And Rural Attempted Suicide

BackgroundAttempted suicide is the person who takes behavior to hurt him/her-self, but the behavior is not leading to the death result successfully, which is a significant risk factor of complete suicide. The research on risk factors of attempted suicide is important in the prevention of suicide behavior.Most researches on polymorphism of BDNF rs6265gene focused on the association of gene polymorphism with mental disorders, and mental disorder is an important independent risk factor of suicide behavior, while there is little evidence of the correlation of rs6265gene polymorphism with suicide behavior which needs to be discussed.According to the previous studies of suicide risk factors, this study was to explore the correlation of BDNF rs6265gene polymorphism with rural attempted suicide and provide scientific basis for rural suicide prevention.ObjectivesTo investigate the epidemiological features of rural attempted suicide in China; to analyze the correlation of BDNFrs6265gene polymorphism with rural attempted suicide; to discuss the influence of social factors and psychological characteristics on rural attempted suicide; to explore high-risk groups of rural attempted suicide in China and provide scientific basis for rural suicide prevention.MethodsAttempted suicides occurred from October1st.2009to March31st,2011were collected from6countries (Zoucheng, Penglai,Tengzhou, Lijin, Ju’nan and Nnigyang) which were chosen from diseases surveillance points of Shandong Province, China. Each attempted suicide or paired control matched with the same age (±3years), same gender, and neighboring residence as the suicide was interviewed by trained interviewers. Instrument:general information questionnaire which includes demographic and social information; semi-structured questionnaire that includes content of attempted suicide behavior; Interview for Recent Life Events(IRLE); FACES-Ⅱ-CV; Duke Social Support Index(DSSI); Life Satisfaction Index A(LSIA); Self-Esteem Scale(SES); Dickman Impulsivity Inventory(DII); Simplified Coping Style Questionnaire(SCSQ); State-Trait Anxiety Inventory(STAI); Center for Epidemiologic Studies Depression Scale(CES-D); Beck Hopelessness Scale(BHS); Structured Clinical Interview for DSM-IV Axis I Disorders,2001, Research Version.Experiment method:blood sample collection, DNA extraction and testing of BDNF rs6365gene polymorphism by the method of PCR-LDR.Statistics method:to describe and analyze the data using software of SPSS16.0and a=0.05was considered as the significant level.X2test was used to test the different distribution of genotype and allele frequency of BDNF rs6265gene. To analyze the risk factors of attempted suicide by X2-test,t-test and Logistic regression model analysis; CART classification tree analysis was used to explore the high risk population of rural attempted suicide.Main ResultsAmong the364attempted suicides interviewed in the current study, the female attempted suicides were249(68.4%) and the male were115(31.6%). The average age of the female attempted suicides was42.67±12.98and that of the male was46.76±13.28. About324(89.0%) attempted suicide behavior occurred in their home.306(84.1%) of them took suicide action by ingestion of agriculture poisons,31(8.5%) of them has the history of family suicide behavior and29(8.0%) experienced previous suicide behavior. The main reasons of attempted suicide behavior were as followed:interpersonal conflict, life pressure, suffering from physical illnesses and mental disorders.Among the364case-controls, there were statistically significant in education level, occupation, family income, store of pesticides, social support level and personality traits,(all P<0.05).In the analysis of the distribution of BDNFrs6265genotype, no relative factor was proved to be correlated with rs6265gene polymorphism. There was no association between rs6265gene polymorphism and mental disorders (X2=5.305, P=0.070). G alleles might be associated with alcohol dependence, OR (95%CI)=0.312(0.145,0.674), and the association was significant after adjusting the influence of age and gender, OR (95%CT)=0.265(0.108,0.650), while, there was no association between rs6265gene polymorphism and depression,(P>0.05).No statistically significant difference was found between case-control groups on the distribution of AA/AG/GG genotype, among male and female respectively (both, P>0.05); there was no statistical difference in the distribution of G or A alleles in the two group (case and control)(both, P>0.05); the distribution of AA/GG genotypes was no statistical difference between case and control groups after controlling gender influence (both, P>0.05).The high risk characteristic clusters of rural attempted suicide behavior as followed: depression, negative life events and mental disorders; depression, negative life events and hopelessness; impulsion, hopelessness and negative life events; depression and negative life events.Foundation of high risk assessment score model of rural attempted suicide:Y=mental disorder*13+hopelessness*12+depression*27+negative life events*27-high education level*14+positive coping capacity*10-life satisfaction*12-social support*13.ConclusionsThere is no association of BDNFrs6265genotype and allele frequency with rural attempted suicide, and rs6265polymorphism may not be susceptibility gene of suicide, while the conclusion needs more study to prove; the high risk clusters of rural suicide screened by CART tree analysis need get more attention in the suicide prevention; people among cases of follow-up with low self-esteem, depression, anxiety and hopelessness may be the high risk group of re-committing suicide, and effective screen or measurements need to be taken.