Table 3.
Pooled odds ratios for experimental group versus control group in meta-analyses
| Subgroups | No. of studies | Random model | Test of heterogeneity | Egger’s test for publication bias | |||||
|---|---|---|---|---|---|---|---|---|---|
|
|
|
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| OR (95% CI) | Z | P value | Q | P value | I2 (%) | t | P value | ||
| Overall effects | 15 | 1.01 (0.96, 1.06) | 0.28 | 0.78 | 16.74 | 0.27 | 16.4 | -1.80 | 0.09 |
| Sample size | |||||||||
| More than 1000 | 7 | 1.02 (0.97, 1.08) | 0.80 | 0.42 | 3.78 | 0.71 | 0.0 | 0.33 | 0.75 |
| Less than or equal to 1000 | 8 | 0.87 (0.73, 1.03) | 1.62 | 0.11 | 9.79 | 0.20 | 28.5 | -1.11 | 0.31 |
| Mean duration of follow-up | |||||||||
| More than 36 months | 8 | 1.02 (0.96, 1.08) | 0.58 | 0.56 | 5.7 | 0.58 | 0.0 | -0.44 | 0.68 |
| Less than or equal to 36 months | 7 | 0.97 (0.86, 1.09) | 0.58 | 0.56 | 10.45 | 0.11 | 42.6 | -1.69 | 0.15 |
| Folic acid food reinforcement | |||||||||
| Yes | 7 | 0.99 (0.92, 1.07) | 0.21 | 0.83 | 3.88 | 0.69 | 0.0 | 0.93 | 0.39 |
| No | 8 | 1.02 (0.95, 1.09) | 0.58 | 0.56 | 12.55 | 0.08 | 44.2 | -2.44 | 0.05 |