Table 2

Relative risks of the effects of vitamin E on stroke for the pooled population and its subgroup analysis

Variables	N	Risk ratio	95% CI	I² (%)	P value	Forest plot
Total stroke	12	0.98	0.92–1.04	0	0.57	Online supplemental figure S1
Type of prevention
Primary	7	0.96	0.87–1.05	0	0.33	Online supplemental figure S2
Secondary	5	1.00	0.90–1.12	32	0.93	Online supplemental figure S2
Source of vit E
Synthetic	7	0.97	0.90–1.04	0	0.41	Online supplemental figure S3
Natural	3	1.00	0.84–1.18	54	0.97	Online supplemental figure S3
Dosage of vit E
High	9	0.99	0.91–1.07	1	0.72	Online supplemental figure S4
Low	3	0.99	0.88–1.10	14	0.80	Online supplemental figure S4
Total stroke (vitamin E alone)	4	1.04	0.91–1.19	0	0.56	Online supplemental figure S5
Fatal stroke	11	0.96	0.77–1.20	32	0.73	Online supplemental figure S6
Type of prevention
Primary	7	1.03	0.68–1.55	45	0.90	Online supplemental figure S7
Secondary	4	0.93	0.76–1.14	2	0.48	Online supplemental figure S7
Source of vit E
Synthetic	6	0.94	0.72–1.24	47	0.67	Online supplemental figure S8
Natural	4	0.88	0.59–1.29	0	0.51	Online supplemental figure S8
Dosage of vit E
High	7	0.96	0.77–1.19	0	0.72	Online supplemental figure S9
Low	4	1.01	0.66–1.55	68	0.97	Online supplemental figure S9
Non-fatal stroke	9	0.96	0.88–1.05	20	0.35	Online supplemental figure S10
Type of prevention
Primary	5	0.93	0.84–1.03	0	0.16	Online supplemental figure S11
Secondary	4	0.96	0.82–1.13	46	0.65	Online supplemental figure S11
Source of vit E
Synthetic	5	0.99	0.87–1.12	39	0.83	Online supplemental figure S12
Natural	3	0.89	0.74–1.08	27	0.25	Online supplemental figure S12
Dosage of vit E
High	6	0.95	0.85–1.07	14	0.42	Online supplemental figure S13
Low	3	0.99	0.82–1.19	53	0.88	Online supplemental figure S13
Haemorraghic stroke
Total haemorrhagic stroke	7	1.17	0.98–1.39	0	0.08	Online supplemental figure S14
Ischaemic stroke
Total ischaemic stroke	7	0.92	0.85–0.99	5	0.04	Online supplemental figure S15