There are several previous studies on the association of vitamin E with prevention of stroke but the findings remain controversial.We have conducted a systematic review,meta-analysis together with trial sequential ana...There are several previous studies on the association of vitamin E with prevention of stroke but the findings remain controversial.We have conducted a systematic review,meta-analysis together with trial sequential analysis of randomised controlled trials to evaluate the effect of vitamin E supplementation versus placebo/no vitamin E on the risk reduction of total,fatal,non-fatal,haemorrhagic and ischaemic stroke.Relevant studies were identified by searching online databases through Medline,PubMed and Cochrane Central Register of Controlled Trials.A total of 18 studies with 148016 participants were included in the analysis.There was no significant difference in the prevention of total stroke(RR(relative risk)=0.98,95% CI 0.92-1.04,p=0.57),fatal stroke(RR=0.96,95% CI 0.77-1.20,p=0.73)and non-fatal stroke(RR=0.96,95% CI 0.88-1.05,p=0.35).Subgroup analyses were performed under each category(total stroke,fatal stroke and non-fatal stroke)and included the following subgroups(types of prevention,source and dosage of vitamin E and vitamin E alone vs control).The findings in all subgroup analyses were statistically insignificant.In stroke subtypes analysis,vitamin E showed significant risk reduction in ischaemic stroke(RR=0.92,95% CI 0.85-0.99,p=0.04)but not in haemorrhagic stroke(RR=1.17,95%CI 0.98-1.39,p=0.08).However,the trial sequential analysis demonstrated that more studies were needed to control random errors.Limitations of this study include the following:trials design may not have provided sufficient power to detect a change in stroke outcomes,participants may have had different lifestyles or health issues,there were a limited number of studies available for subgroup analysis,studies were mostly done in developed countries,and the total sample size for all included studies was insufficient to obtain a meaningful result from meta-analysis.In conclusion,there is still a lack of statistically significant evidence of the effects of vitamin E on the risk reduction of stroke.Nevertheless,vitamin E may offer some benefits in the prevention of ischaemic stroke and additional well-designed randomised controlled trials are needed to arrive at a definitive finding.PROSPERO registration number:CRD42020167827.展开更多
文摘There are several previous studies on the association of vitamin E with prevention of stroke but the findings remain controversial.We have conducted a systematic review,meta-analysis together with trial sequential analysis of randomised controlled trials to evaluate the effect of vitamin E supplementation versus placebo/no vitamin E on the risk reduction of total,fatal,non-fatal,haemorrhagic and ischaemic stroke.Relevant studies were identified by searching online databases through Medline,PubMed and Cochrane Central Register of Controlled Trials.A total of 18 studies with 148016 participants were included in the analysis.There was no significant difference in the prevention of total stroke(RR(relative risk)=0.98,95% CI 0.92-1.04,p=0.57),fatal stroke(RR=0.96,95% CI 0.77-1.20,p=0.73)and non-fatal stroke(RR=0.96,95% CI 0.88-1.05,p=0.35).Subgroup analyses were performed under each category(total stroke,fatal stroke and non-fatal stroke)and included the following subgroups(types of prevention,source and dosage of vitamin E and vitamin E alone vs control).The findings in all subgroup analyses were statistically insignificant.In stroke subtypes analysis,vitamin E showed significant risk reduction in ischaemic stroke(RR=0.92,95% CI 0.85-0.99,p=0.04)but not in haemorrhagic stroke(RR=1.17,95%CI 0.98-1.39,p=0.08).However,the trial sequential analysis demonstrated that more studies were needed to control random errors.Limitations of this study include the following:trials design may not have provided sufficient power to detect a change in stroke outcomes,participants may have had different lifestyles or health issues,there were a limited number of studies available for subgroup analysis,studies were mostly done in developed countries,and the total sample size for all included studies was insufficient to obtain a meaningful result from meta-analysis.In conclusion,there is still a lack of statistically significant evidence of the effects of vitamin E on the risk reduction of stroke.Nevertheless,vitamin E may offer some benefits in the prevention of ischaemic stroke and additional well-designed randomised controlled trials are needed to arrive at a definitive finding.PROSPERO registration number:CRD42020167827.
