Risk Factors Analyze For Subarachnoid Hemorrhage

PART I: Alcohol consumption and risk of subarachnoid hemorrhageObjective:The association between alcohol consumption and the risk of subarachnoid hemorrhage(SAH)is inconsistent.Thus,meta-and a dose-response analyses are presented with the purpose of assessing their associations.Methods: A systematic literature search was performed using Pubmed and Embase electronic databases for pertinent observational studies.Random-effects or fixed-effect models were employed to combine the estimates of the relative risks(RRs)with corresponding 95% confidence intervals(CIs).A dose-response pattern was conducted for further analysis.Results:The current meta-analysis includes 14 observational studies reporting data on 483,553 individuals and 2,556 patients.The combined RRs of light alcohol consumption(<15 g/day)and moderate alcohol consumption(15-30 g/day)compared with teetotal individuals were 1.27(95% CI: 0.95,1.68)and 1.33(95% CI: 0.84,2.09),respectively,which indicated no significant association between light-to-moderate alcohol consumption and SAH.An increased risk of SAH was noted in heavy alcohol consumption(>30 g/day)when compared with no alcohol consumption,as demonstrated by a result of 1.78(95% CI: 1.46,2.17).Dose-response analysis showed evidence of a linear association(P=0.0125)between alcohol consumption and SAH.The risk of SAH increased by 12.1% when alcohol consumption was increased by 10 g/day.Conclusion:Therefore,heavy alcohol consumption was found to be associated with an increased risk of SAH.Furthermore,the association between SAH and alcohol consumption has clinical relevance with regard to risk factor modification and the primary and secondary prevention of SAH.PART II: Diabetes Mellitus and the Risk of Subarachnoid HemorrhageObjective: This systematic review aimed to define the relationship between diabetes mellitus(DM)and the risk of aneurysmal subarachnoid haemorrhage(SAH).Methods: Studies associated with DM and SAH published until March 2016 were retrieved from Pubmed,Embase,Web of Science,and Cochrane Library databases.A random-effects model wasused to calculate the relative risks(RRs)with 95% confidence intervals(CIs).Results: Eighteen observational studies were retrieved.The overall RRs for DM and SAH were RRs=0.59(95% CI: 0.44,0.79),with moderate heterogeneity(I2=55.7%,P=0.000).Subgroupanalysis by study quality revealed a reduced association between DM and SAH risk in high qualitystudies only(RRs=0.40,95% CI: 0.29,0.56;I2=0.0%,P=0.549),therefore studyquality may be a source of heterogeneity.Conclusion: A potential decreased risk of SAH in DM patients was found in high quality studies.Further studies are required to confirm this causal relationship and to investigate the biologicalmechanisms.