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Table 2 The results of subgroup analysis

From: The preventive efficacy of vitamin B supplements on the cognitive decline of elderly adults: a systematic review and meta-analysis

Outcome measures Subgroup The Num
of studies
Pooled estimate
[SMD/MD (95 %CI)]
P value I2(%) Test for subgroup differences
global cognitive function Treatment duration ≤ 12 months 7 0.35(-0.15, 0.84) P = 0.17 87 P = 0.67
> 12 months 8 0.23(0.07, 0.40) P = 0.006 91  
participants MCI patients 5 0.82(0.20, 1.45) P = 0.01 95 P = 0.03*
EAWCI 10 0.13(0.03, 0.23) P = 0.01 66  
information processing speed Treatment duration ≤ 12 months 5 -0.19(-0.38, 0.01) P = 0.06 39 P = 0.007*
> 12 months 4 0.16(0.01, 0.31) P = 0.04 64  
participants MCI patients 1 0.04(-0.28, 0.36) P = 0.79 NA P = 0.89
EAWCI 9 0.07(-0.13, 0.27) P = 0.50 81  
episodic memory Treatment duration ≤ 12 months 7 -0.09(-0.27, 0.09) P = 0.34 40 P = 0.09
> 12 months 6 0.08(0.02, 0.13) P = 0.01 0  
participants MCI patients 4 0.42(-0.24, 1.08) P = 0.21 94 P = 0.26
EAWCI 11 0.04(-0.04, 0.12) P = 0.34 28  
executive function Treatment duration ≤ 12 months 4 0.01(-0.14, 0.17) P = 0.87 0 P = 0.21
> 12 months 5 -0.29(-0.75, 0.16) P = 0.20 96  
participants MCI patients 3 -0.33(-0.81, 0.15) P = 0.18 89 P = 0.59
EAWCI 8 -0.17(-0.51, 0.17) P = 0.34 94  
Hcy Treatment duration ≤ 12 months 7 -4.77(-6.28, -3.27) P < 0.01 78 P = 0.68
> 12 months 5 -4.41(-5.27, -3.54) P < 0.01 82  
participants MCI patients 3 -5.45(-6.51, -4.39) P < 0.01 81 P = 0.05
EAWCI 8 -4.13(-4.93, -3.32) P < 0.01 65  
  1. Abbreviations: SMD standardized mean difference, MD mean difference, CI confidence interval,MCI mild cognitive impairment, EAWCI elderly adults without cognitive impairment, Hcy Homocysteine, NA not applicable
  2. *P < 0.05