Table 2. Subgroup analysis for the effect of B vitamins supplementation on stroke.

Group	RR and 95%CI	P value	Heterogeneity (%)	P value for heterogeneity
Man/woman ratio
>2	0.83 (0.69-1.00)	0.047	37	0.12
Excluding DIVINe Study Group[9]	0.83 (0.71-0.98)	0.03	27	0.21
<2	0.96 (0.87-1.06)	0.45	0	0.43
Stroke Prevention
Primary prevention	0.91 (0.73-1.12)	0.37	27	0.19
Excluding DIVINe Study Group[9]	0.90 (0.74-1.09)	0.29	15	0.31
Secondary prevention	0.91 (0.82-1.02)	0.11	29	0.21
Baseline homocysteine (umol/L)
<14	0.90 (0.77-1.06)	0.22	38	0.14
14-20	1.02 (0.73-1.43)	0.91	42	0.18
Excluding DIVINe Study Group[9]	0.94 (0.82-1.07)	0.33	0	0.51
>20	0.78 (0.58-1.05)	0.10	0	0.46
Homocysteine lowering
> 20%	0.89 (0.78-1.02)	0.09	31	0.17
Excluding DIVINe Study Group[9]	0.90 (0.80-1.00)	0.052	18	0.29
<20%	0.86 (0.63-1.16)	0.33	37	0.19
Treatment regimens
Folic acid plus vitamin B12 plus vitamin B6	0.90 (0.81-1.01)	0.07	17	0.27
Excluding DIVINe Study Group[9]	0.91 (0.82-0.99)	0.04	5	0.40
Folic acid plus vitamin B12	1.01 (0.86-1.20)	0.86	-	-
Folic acid only	0.75 (0.36-1.57)	0.44	49	0.14
Folic acid (mg)
<1	0.74 (0.58-0.94)	0.01	0	0.73
1-3	0.95 (0.83-1.09)	0.45	43	0.08
Excluding DIVINe Study Group[9]	0.94 (0.83-1.07)	0.36	37	0.13
>3	0.95 (0.72-1.25)	0.72	0	0.59
Vitamin B6 (mg)
>40	0.91 (0.73-1.12)	0.36	32	0.21
40 or less	0.90 (0.78-1.04)	0.15	18	0.28
Excluding DIVINe Study Group[9]	0.91 (0.83-1.01)	0.09	0	0.46
Vitamins B12 (mg)
<0.5	0.91 (0.82-1.01)	0.07	0	0.45
1	0.99 (0.80-1.22)	0.90	53	0.07
Excluding DIVINe Study Group[9]	0.97 (0.80-1.16)	0.71	47	0.13
2	0.90 (0.58-1.38)	0.62	-	-
Disease status
Renal disease	0.87 (0.63-1.18)	0.37	28	0.22
Excluding DIVINe Study Group[9]	0.86 (0.67-1.10)	0.23	1	0.41
Other	0.92 (0.83-1.02)	0.12	26	0.19
Duration of the follow-up period (years)
>3	0.89 (0.79-1.01)	0.07	31	0.13
Excluding DIVINe Study Group[9]	0.89 (0.80-1.00)	0.048	24	0.20
<3	0.99 (0.82-1.21)	0.95	0	0.47
Study quality
High	0.92 (0.83-1.02)	0.11	21	0.22
Excluding DIVINe Study Group[9]	0.92 (0.84-1.01)	0.08	11	0.34
Low	0.80 (0.54-1.19)	0.27	45	0.14