Background
Methods
Literature search
Inclusion and exclusion criteria
Data extraction and quality assessment
Statistical analyses
Results
Study characteristics
First author | Year | Country | Ethnicity | Female percentage (%) | HWE | Age | NOS | Method of DR ascertainment | Genotyping method | Cases (n) | Controls (n) | MAF (%) | ||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Cases | Controls | Cases | Controls | |||||||||||
Kamiuchi | 2002 | Japan | Asians | 52.0 | 56.8 | Yes | 64.3 ± 8.9 | 64.1 ± 9.1 | 7 | Ophthalmoscopy and fluorescein angiography | PCR-RFLP | 81 | 50 | 50.0 |
Liu | 2006 | China | Asians | PDR: 66.3 NPDR: 67.3 | 50.0 | Yes | PDR: 55.0 ± 12.4 NPDR: 63.7 ± 7.9 | 50.2 ± 10.6 | 7 | NA | DNA sequencing | 132 | 80 | 38.8 |
Petrovic | 2008 | Slovenia | Caucasians | 53.3 | 60.1 | Yes | 65.2 ± 9.9 | 66.9 ± 11.5 | 7 | Fundus photographs | Allele-specific PCR | 195 | 143 | 42.3 |
Zhou | 2010 | China | Asians | 49.0 | 48.0 | No | 55.6 ± 8.8 | 55.3 ± 8.6 | 6 | Ophthalmoscopy and fluorescein angiography | PCR-RFLP | 102 | 150 | 33.0 |
Zhu | 2010 | China | Asians | NA | NA | Yes | NA | NA | 6 | Ophthalmoscopy and fluorescein angiography | PCR-RFLP | 40 | 30 | 16.7 |
Balasubbu | 2010 | India | Asians | 30.0 | 42.0 | Yes | 57 ± 9 | 59 ± 11 | 7 | Ophthalmoscopy and fundus photographs | SNaPshot PCR | 345 | 359 | 48.2 |
Vinita | 2012 | India | Asians | 35.7 | 37.6 | Yes | 58.8 ± 8.6 | 64.3 ± 9.0 | 8 | Fundus photographs | DNA sequencing | 199 | 157 | 54.8 |
Lv | 2016 | China | Asians | 56.3 | 52.6 | Yes | 62.4 ± 11.9 | 60.2 ± 11.7 | 7 | Fundus photographs | PCR-LDR | 448 | 344 | 29.4 |
Li | 2016 | China | Asians | PDR: 51.7 NPDR: 46.2 | 43.8 | Yes | PDR: 66.9 ± 6.9 NPDR: 63.1 ± 6.8 | 54–82 | 7 | NA | DNA sequencing | 250 | 87 | 41.4 |
Data synthesis
Evaluation | Number of studies | OR (95% CI) | P | P for heterogeneity | I2 (%) |
---|---|---|---|---|---|
GA + GG versus AA | |||||
Total | 9 | 1.00 (0.66–1.50) | 0.987 | < 0.001 | 84.0 |
Asians | 8 | 0.96 (0.61–1.50) | 0.843 | < 0.001 | 85.2 |
Caucasians | 1 | 1.40 (0.86–2.27) | 0.173 | NA | NA |
PDR | 4 | 1.22 (0.61–2.47) | 0.577 | < 0.001 | 86.8 |
NPDR | 3 | 0.60 (0.29–1.21) | 0.151 | 0.007 | 80.0 |
GG versus GA + AA | |||||
Total | 9 | 1.24 (0.86–1.77) | 0.245 | 0.003 | 65.3 |
Asians | 8 | 1.15 (0.79–1.68) | 0.469 | 0.008 | 63.2 |
Caucasians | 1 | 2.00 (1.15–3.48) | 0.014 | NA | NA |
PDR | 4 | 1.90 (0.80–4.50) | 0.146 | < 0.001 | 84.2 |
NPDR | 3 | 0.92 (0.58–1.47) | 0.724 | 0.477 | 0.0 |
GG versus AA | |||||
Total | 9 | 1.14 (0.68–1.92) | 0.611 | < 0.001 | 78.5 |
Asians | 8 | 1.04 (0.60–1.81) | 0.887 | < 0.001 | 78.1 |
Caucasians | 1 | 2.21 (1.16–4.22) | 0.016 | NA | NA |
PDR | 4 | 1.91 (0.64–5.73) | 0.246 | < 0.001 | 87.6 |
NPDR | 3 | 0.77 (0.47–1.25) | 0.286 | 0.171 | 43.5 |
G allele versus A allele | |||||
Total | 9 | 1.08 (0.81–1.45) | 0.592 | < 0.001 | 85.7 |
Asians | 8 | 1.05 (0.76–1.44) | 0.790 | < 0.001 | 86.3 |
Caucasians | 1 | 1.44 (1.06–1.95) | 0.021 | NA | NA |
PDR | 4 | 1.34 (0.71–2.52) | 0.364 | < 0.001 | 82.5 |
NPDR | 3 | 0.71 (0.43–1.17) | 0.180 | 0.011 | 77.9 |
Heterogeneity and publication bias
Dominant model | Recessive model | GG versus AA contrast | G allele versus A allele contrast | |
---|---|---|---|---|
P value | 0.754 | 0.498 | 0.641 | 0.579 |