Table 1 SNPs information and minor allele frequencies among cases and controls

OPRM1

rs648893

6:154117494

G

0.26

0.29

G

0.27

0.49

rs609148

6:154109880

A

0.26

0.56

A

0.28

0.91

rs495491

6:154061407

G

0.21

0.02

G

0.21

0.14

rs3823010

6:154058017

A

0.08

1.00

A

0.09

0.58

rs1799971

6:154039662

G

0.14

1.00

G

0.10

0.80

rs511435

6:154047412

T

0.16

0.5

T

0.18

0.36

rs524731

6:154053957

A

0.15

0.39

A

0.17

0.63

rs1381376

6:154072123

T

0.08

1.00

T

0.1

0.30

rs3778156

6:154083178

G

0.08

0.54

G

0.09

0.59

rs2075572

6:154090869

G

0.44

0.27

G

0.48

0.24

rs548646

6:154097012

T

0.32

0.41

T

0.34

0.32

rs671531

6:154119607

A

0.32

0.68

A

0.34

0.16

OPRK1

rs12675595

8:53255365

A

0.1

0.79

A

0.1

0.44

rs1051660

8:53251002

A

0.11

0.64

A

0.12

0.53

rs6985606

8:53248556

T

0.33

1.00

T

0.33

1.00

rs997917

8:53239818

C

0.46

0.59

C

0.44

0.14

rs702764

8:53229597

C

0.20

0.89

C

0.20

0.21

rs963549

8:53229264

T

0.2

1.00

T

0.2

0.21

OPRD1

rs569356

1:28810174

G

0.08

0.75

G

0.07

1.00

rs1042114

1:28812463

G

0.08

1.00

G

0.08

0.19

rs678849

1:28818676

T

0.46

0.36

T

0.45

0.86

rs2236857

1:28835097

C

0.35

0.14

C

0.38

1.00

rs2236855

1:28835487

A

0.34

0.13

A

0.38

1.00

rs2298896

1:28839626

G

0.41

0.30

G

0.45

0.59

rs421300

1:28843081

G

0.42

0.58

G

0.45

0.32

rs529520

1:28848434

C

0.46

0.27

C

0.43

0.07

rs12749204

1:28849701

G

0.23

0.61

G

0.25

0.72

rs2234918

1:28863085

T

0.46

0.86

T

0.46

0.79