Effects of vitamin E on stroke: a systematic review with meta-analysis and trial sequential analysis
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 supplem...
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doaj-7ba880ccf494458a899ccfac073d51db2021-09-25T11:30:05ZengBMJ Publishing GroupStroke and Vascular Neurology2059-86962021-03-016110.1136/svn-2020-000519Effects of vitamin E on stroke: a systematic review with meta-analysis and trial sequential analysisRenly Lim0Hong Chuan Loh1Kai Wei Lee2Chin Yik Ooi3Deik Roy Chuan4Yuen Kah Hay5Nurzalina Abdul Karim Khan62 Clinical and Health Sciences, University of South Australia, Adelaide, South Australia, Australia 1 Clinical Research Center, Hospital Seberang Jaya, Ministry of Health Malaysia, Seberang Jaya, Malaysia3 Department of Pre-Clinical Sciences, Faculty of Medicine and Health Sciences, Universiti Tunku Abdul Rahman - Kampus Bandar Sungai Long, Kajang, Malaysia1 Clinical Research Center, Hospital Seberang Jaya, Ministry of Health Malaysia, Seberang Jaya, Malaysia1 Clinical Research Center, Hospital Seberang Jaya, Ministry of Health Malaysia, Seberang Jaya, Malaysia5 School of Pharmaceutical Sciences, Universiti Sains Malaysia, Minden, Malaysia5 School of Pharmaceutical Sciences, Universiti Sains Malaysia, Minden, MalaysiaThere 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 148 016 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.https://svn.bmj.com/content/6/1/109.full |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Renly Lim Hong Chuan Loh Kai Wei Lee Chin Yik Ooi Deik Roy Chuan Yuen Kah Hay Nurzalina Abdul Karim Khan |
spellingShingle |
Renly Lim Hong Chuan Loh Kai Wei Lee Chin Yik Ooi Deik Roy Chuan Yuen Kah Hay Nurzalina Abdul Karim Khan Effects of vitamin E on stroke: a systematic review with meta-analysis and trial sequential analysis Stroke and Vascular Neurology |
author_facet |
Renly Lim Hong Chuan Loh Kai Wei Lee Chin Yik Ooi Deik Roy Chuan Yuen Kah Hay Nurzalina Abdul Karim Khan |
author_sort |
Renly Lim |
title |
Effects of vitamin E on stroke: a systematic review with meta-analysis and trial sequential analysis |
title_short |
Effects of vitamin E on stroke: a systematic review with meta-analysis and trial sequential analysis |
title_full |
Effects of vitamin E on stroke: a systematic review with meta-analysis and trial sequential analysis |
title_fullStr |
Effects of vitamin E on stroke: a systematic review with meta-analysis and trial sequential analysis |
title_full_unstemmed |
Effects of vitamin E on stroke: a systematic review with meta-analysis and trial sequential analysis |
title_sort |
effects of vitamin e on stroke: a systematic review with meta-analysis and trial sequential analysis |
publisher |
BMJ Publishing Group |
series |
Stroke and Vascular Neurology |
issn |
2059-8696 |
publishDate |
2021-03-01 |
description |
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 148 016 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. |
url |
https://svn.bmj.com/content/6/1/109.full |
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