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Table 4 Meta-analysis of MTHFR A1298C polymorphism to ASD risk under the five genetic models

From: Association between MTHFR C677T/A1298C and susceptibility to autism spectrum disorders: a meta-analysis

Genetic Models Fixed/ Random effect
OR(95%CI)
Heterogeneity
P
I2(%) Publication Bias P of Egger’s/Begg test
Allele Contrast (C vs A) 1.17 (0.91–1.50)b 0.000 81.7 0.210/0.010
 Mandatory fortification with folate
  Yes 0.91 (0.81–1.03)a 0.153 40.3 0.086/0.098
  No 1.84 (1.08–3.14)b* 0.002 86.0 0.086/0.095
 Population
  Asian 1.31 (0.81–2.14)b 0.002 84.4 0.296/0.380
  Caucasian 1.11 (0.82–1.49)b 0.000 80.9 0.548/0.045
 Sample source
  Hospital-based 1.45 (0.88–2.39)b 0.000 89.5 0.221/0.021
  Population-based 0.96 (0.84–1.10)a 0.074 53.0 0.204/0.462
HWE
  Yes 1.13 (0.84–1.52)b 0.000 80.9 0.368/0.043
  No 1.25 (0.73–2.15)b 0.000 87.2 0.282/0.296
Heterozygote (AC vs AA) 1.11 (0.82–1.50)b 0.000 73.5 0.001/0.049
 Mandatory fortification with folate
  Yes 0.87 (0.74–1.02)a 0.302 17.6 0.382/0.462
  No 2.23 (0.98–5.09)b 0.000 82.7 0.026/0.086
 Population
  Asian 1.29 (0.68–2.44)b 0.015 76.3 0.532/1.000
  Caucasian 1.04 (0.72–1.50)b 0.001 74.7 0.002/0.230
 Sample source
  Hospital-based 1.11 (0.71–1.74)b 0.004 74.0 0.090/0.462
  Population-based 1.15 (0.72–1.86)b 0.001 78.4 0.009/0.221
 HWE
  Yes 1.04 (0.73–1.50)b 0.001 74.6 0.001/0.133
  No 1.28 (0.66–2.47)b 0.013 76.9 0.578/1.000
Homozygote (CC vs AA) 1.31 (0.82–2.09)b 0.000 72.0 0.025/0.152
 Mandatory fortification with folate
  Yes 0.89 (0.67–1.18)a 0.260 24.2 0.139/0.462
  No 2.98 (1.17–7.58)b 0.002 75.8 0.143/0.221
 Population
  Asian 1.78 (0.88–3.62)b 0.041 68.8 0.811/1.000
  Caucasian 1.11 (0.62–2.01)b 0.002 70.5 0.073/0.368
 Sample source
  Hospital-based 1.87 (0.74–4.77)b 0.000 83.6 0.044/0.462
  Population-based 1.02 (0.76–1.34)a 0.208 32.0 0.066/1.000
 HWE
  Yes 1.27 (0.68–2.35)b 0.001 72.5 0.072/0.230
  No 1.45 (0.65–3.24)b 0.014 76.7 0.966/1.000
Dominant (CC + AC vs AA) 1.19 (0.87–1.64)b 0.002 79.6 0.000/0.049
 Mandatory fortification with folate
  Yes 0.87 (0.74–1.02)a 0.205 32.5 0.198/0.221
  No 2.45 (1.16–5.15)b* 0.000 84.5 0.005/0.086
 Population
  Asian 1.38 (0.89–2.14)b 0.054 65.8 0.291/1.000
  Caucasian 1.13 (0.75–1.72)b 0.000 82.0 0.001/0.230
 Sample source
  Hospital-based 1.43 (0.81–2.50)b 0.000 86.6 0.019/0.462
  Population-based 1.03 (0.71–1.49)b 0.011 69.2 0.014/0.221
 HWE
  Yes 1.14 (0.76–1.73)b 0.000 81.9 0.001/0.230
  No 1.34 (0.80–2.23)b 0.023 73.4 0.306/1.000
Recessive (CC vs AC + AA) 1.17 (0.76–1.78)b 0.001 69.4 0.081/0.152
 Mandatory fortification with folate
  Yes 0.94 (0.72–1.24)a 0.363 7.7 0.192/0.462
  No 1.93 (0.70–1.25)b 0.000 82.6 0.240/0.806
 Population
  Asian 1.52 (0.54–4.33)b 0.000 87.3 0.546/1.000
  Caucasian 0.99 (0.64–1.55)b 0.486 52.8 0.174/0.368
 Sample source
  Hospital-based 1.74 (0.76–3.99)b 0.000 80.3 0.063/0.462
  Population-based 0.90 (0.69–1.19) a 0.235 27.9 0.710/1.000
 HWE
  Yes 1.12 (0.69–1.80)b 0.025 58.5 0.163/0.368
  No 1.24 (0.46–3.36)b 0.001 86.6 0.676/1.000
  1. *:P < 0.05
  2. aFixed effect
  3. bRandom effect