Background
Methods
Literature search strategy
Inclusion and exclusion criteria
Data extraction
Statistical methods
Results
Characteristics of included studies
First author | Year | Country | Study design | Ethnicity | Sample size | Source of controls | Genotyping method | Age (mean) | Knee OA definition | ||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Case | Control | Case | Control | Radiographic* | Clinical†
| TKR | |||||||
Southama
| 2007 | UK | Case–control | Caucasian | 349 | 822 | HB | PCR-RFLP | 65 | 69 |
+
| ||
Southamb
| 2007 | Spain | Case–control | Caucasian | 274 | 1196 | HB | TaqMan | NA | >55.0 |
+
| ||
Miyamotoa
| 2007 | Japan | Case–control | Asian | 718 | 861 | HB | TaqMan, Invader, DNA fragment analysis or Direct sequence | 71.9 | 49.4 |
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| ||
Miyamotob
| 2007 | China | Case–control | Asian | 313 | 485 | HB | TaqMan, Invader, DNA fragment analysis or Direct sequence | 58.8 | 56.8 |
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| ||
Tsezou | 2007 | Greece | Case–control | Caucasian | 251 | 268 | HB | Direct sequence | 67.9 | 65.2 |
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| ||
Chapman | 2008 | Netherlands | Cohort study | Caucasian | 142 | 724 | PB | Mass spectrometry | 60.4 | 59.6 |
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| ||
Valdesa
| 2009 | UK | Case–control | Caucasian | 735 | 654 | HB | Allele-specific PCR | 68.5 | 66.9 |
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| ||
Valdesb
| 2009 | UK | Cohort study | Caucasian | 264 | 512 | PB | Allele-specific PCR | 66.3 | 63 |
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| ||
Vaes | 2009 | Netherlands | Cohort study | Caucasian | 667 | 2097 | PB | TaqMan | >55.0 | >55.0 |
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| ||
Evangeloua
| 2009 | Iceland | Cohort study | Caucasian | 1071 | 1169 | PB | Centaurus platform | 74.8 | 74.8 |
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| ||
Evangeloub
| 2009 | UK | Twins study | Caucasian | 177 | 548 | NA | Illumina platform | 54.3 | 54.3 |
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| ||
Evangelouc
| 2009 | Finland | Family-based study | Caucasian | 109 | 209 | NA | Mass spectrometry | 67 | 58 |
+
|
+
| |
Cao | 2010 | Korea | Case–control | Asian | 276 | 298 | PB | PCR-RFLP | 63 | 44 |
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| ||
Tawonsawatruk | 2011 | Thailand | Case–control | Asian | 103 | 103 | HB | PCR-RFLP | 68.5 | 59.25 |
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| ||
Valdea
| 2011 | UK | Cohort study | Caucasian | 867 | 758 | PB | Allele-specific PCR | 66.5 | 66.5 |
+
| ||
Valdesb
| 2011 | Estonian | Cohort study | Caucasian | 65 | 427 | PB | Allele-specific PCR | 47.1 | 47.1 |
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| ||
Valdesc
| 2011 | UK | Cohort study | Caucasian | 1141 | 536 | PB | Allele-specific PCR | 65.5 | 65.5 |
+
|
+
| |
Valdesd
| 2011 | Netherlands | Cohort study | Caucasian | 162 | 1582 | PB | TaqMan | >45.0 | >45.0 |
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| ||
Shin | 2012 | Korea | Cohort study | Asian | 725 | 1737 | PB | High resolution melting analysis | 67.4 | 62.7 |
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| ||
Mhishra | 2013 | India | Case–control | Asian | 300 | 300 | HB | PCR-RFLP | 54.0 | 55.2 |
+
|
+
|
First author | Year | Case | Control | Case | Control |
P
HWE
| ||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
TT | TC | CC | TT | TC | CC | T | C | T | C | |||
Southama
| 2007 | 141 | 168 | 40 | 324 | 372 | 126 | 450 | 248 | 1020 | 624 | 0.262 |
Southamb
| 2007 | 102 | 136 | 36 | 439 | 563 | 194 | 340 | 208 | 1441 | 951 | 0.550 |
Miyamotoa
| 2007 | 444 | 243 | 31 | 473 | 330 | 58 | 1131 | 305 | 1276 | 446 | 0.966 |
Miyamotob
| 2007 | 197 | 97 | 19 | 244 | 193 | 48 | 491 | 135 | 681 | 289 | 0.283 |
Tsezou | 2007 | 95 | 126 | 30 | 99 | 125 | 44 | 316 | 186 | 323 | 213 | 0.669 |
Chapman | 2008 | 54 | 72 | 16 | 289 | 331 | 104 | 180 | 104 | 909 | 539 | 0.558 |
Valdesa
| 2009 | 337 | 313 | 85 | 238 | 329 | 79 | 987 | 483 | 805 | 487 | 0.032 |
Valdesb
| 2009 | 126 | 98 | 35 | 181 | 244 | 84 | 350 | 168 | 606 | 412 | 0.908 |
Vaes | 2009 | 276 | 298 | 93 | 752 | 1014 | 331 | 850 | 484 | 2518 | 1617 | 0.724 |
Evangeloua
| 2009 | 535 | 379 | 157 | 552 | 442 | 175 | 1449 | 693 | 1546 | 792 | 0.000 |
Evangeloub
| 2009 | NA | NA | NA | NA | NA | NA | 230 | 124 | 679 | 417 | NA |
Evangelouc
| 2009 | NA | NA | NA | NA | NA | NA | 124 | 94 | 251 | 167 | NA |
Cao | 2010 | 150 | 115 | 11 | 159 | 113 | 26 | 415 | 137 | 431 | 165 | 0.360 |
Tawonsawatruk | 2011 | 38 | 41 | 11 | 33 | 47 | 23 | 117 | 63 | 113 | 93 | 0.424 |
Valdesa
| 2011 | 413 | 361 | 93 | 294 | 354 | 110 | 1187 | 547 | 942 | 574 | 0.837 |
Valdesb
| 2011 | 32 | 24 | 9 | 168 | 179 | 80 | 88 | 42 | 515 | 339 | 0.010 |
Valdesc
| 2011 | 467 | 511 | 163 | 219 | 237 | 80 | 1445 | 837 | 675 | 397 | 0.229 |
Valdesd
| 2011 | NA | NA | NA | NA | NA | NA | 195 | 107 | 1930 | 1234 | NA |
Shin | 2012 | 382 | 305 | 38 | 942 | 689 | 106 | 1069 | 381 | 2573 | 901 | 0.176 |
Mhishra | 2013 | 124 | 130 | 46 | 84 | 160 | 56 | 378 | 222 | 328 | 272 | 0.188 |
Quantitative assessment
Population | Comparison (Na) | Test of association | Test of heterogeneity | ||
---|---|---|---|---|---|
OR (95% CI) |
P
b
|
P
c
|
I
2
(%) | ||
Overall | C vs. T (20) | 0.85 (0.80-0.90) | 0.000 | 0.019 | 44.1 |
CC vs. TT (17) | 0.73 (0.66-0.81) | 0.000 | 0.328 | 10.8 | |
CT vs. TT (17) | 0.84 (0.76-0.94) | 0.002 | 0.000 | 62.2 | |
CC/CT vs. TT (17) | 0.81 (0.73-0.90) | 0.000 | 0.000 | 61.7 | |
CC vs. CT/TT (17) | 0.81 (0.74-0.86) | 0.000 | 0.623 | 0.0 | |
Ethnicity | |||||
Asian | C vs. T (6) | 0.78 (0.67-0.92) | 0.003 | 0.006 | 69.5 |
CC vs. TT (6) | 0.60 (0.48-0.76) | 0.000 | 0.333 | 12.9 | |
CT vs. TT (6) | 0.80 (0.63-1.02) | 0.071 | 0.002 | 74.3 | |
CC/CT vs. TT (6) | 0.76 (0.60-0.96) | 0.021 | 0.001 | 75.8 | |
CC vs. CT/TT (6) | 0.68 (0.56-0.84) | 0.000 | 0.494 | 0.0 | |
Caucasian | C vs. T (14) | 0.87 (0.82-0.92) | 0.000 | 0.229 | 20.7 |
CC vs. TT (11) | 0.78 (0.70-0.87) | 0.000 | 0.611 | 0.0 | |
CT vs. TT (11) | 0.86 (0.76-0.97) | 0.012 | 0.011 | 56.2 | |
CC/CT vs. TT (11) | 0.83 (0.75-0.93) | 0.001 | 0.020 | 52.6 | |
CC vs. CT/TT (11) | 0.84 (0.76-0.93) | 0.001 | 0.822 | 0.0 | |
Sex | |||||
Females | C vs. T (9) | 0.85 (0.78-0.93) | 0.000 | 0.236 | 23.3 |
CC vs. TT (9) | 0.73 (0.62-0.87) | 0.000 | 0.923 | 0.0 | |
CT vs. TT (9) | 0.81 (0.69-0.95) | 0.011 | 0.029 | 53.2 | |
CC/CT vs. TT (9) | 0.80 (0.69-0.93) | 0.003 | 0.039 | 50.7 | |
CC vs. CT/TT (9) | 0.83 (0.70-0.97) | 0.021 | 0.990 | 0.0 | |
Males | C vs. T (9) | 0.85 (0.74-0.97) | 0.020 | 0.171 | 30.9 |
CC vs. TT (9) | 0.65 (0.50-0.84) | 0.001 | 0.464 | 0.0 | |
CT vs. TT (9) | 0.99 (0.81-1.20) | 0.888 | 0.139 | 34.8 | |
CC/CT vs. TT (9) | 0.90 (0.74-1.09) | 0.272 | 0.107 | 39.1 | |
CC vs. CT/TT (9) | 0.66 (0.51-0.84) | 0.001 | 0.613 | 0.0 |
Overall population
Subgroup analyses by ethnicity
Subgroup analyses by sex
Evaluation of other potential sources of heterogeneity
Subgroup | C vs. T | CC vs. TT | CT vs. TT | CC/CT vs. TT | CC vs. CT/TT | |||||
---|---|---|---|---|---|---|---|---|---|---|
P
h
|
I
2
(%) |
P
h
|
I
2
(%) |
P
h
|
I
2
(%) |
P
h
|
I
2
(%) |
P
h
|
I
2
(%) | |
Source of controls
| ||||||||||
HB | 0.196 | 29.1 | 0.681 | 0.0 | 0.013 | 60.8 | 0.032 | 54.4 | 0.703 | 0.0 |
PB | 0.051 | 46.6 | 0.233 | 23.7 | 0.006 | 62.9 | 0.005 | 64.0 | 0.511 | 0.0 |
Knee OA definition
| ||||||||||
Radiographic | 0.043 | 48.3 | 0.654 | 0.0 | 0.003 | 68.1 | 0.002 | 68.9 | 0.874 | 0.0 |
TKR | 0.206 | 30.5 | 0.132 | 41.0 | 0.187 | 33.3 | 0.184 | 33.6 | 0.153 | 38.0 |