Table 1 DNA methylation observed at CpG sites in the OPRM1 and TLR4 genes and in the LINE1 retrotransposon used to quantify global DNA methylation. Means and standard deviations (SD) are given separately for the “non-persistent pain” and “persistent pain” phenotype groups

OPRM1 CpG site−60

8.26

2.76

8.3

2.74

OPRM1 CpG site−50

5.5

2.8

3.83

2.39

OPRM1 CpG site−32

11.95

5.21

10.29

3.28

OPRM1 CpG site−25

11.39

4.32

10.12

3.17

OPRM1 CpG site−18

8.1

2.71

7.57

2.99

OPRM1 CpG site−14

6.49

2.7

4.93

3.04

TLR4 CpG site−75

2.77

1.36

2.47

1.39

TLR4 CpG site−67

2.82

1.29

2.82

1.43

TLR4 CpG site−58

2.74

1.08

2.49

1.22

TLR4 CpG site−51

2.8

1.22

2.51

1.21

LINE1 CpG site−605

83.6

4.32

84.07

4.2

LINE1 CpG site−593

81.56

4.75

77.56

1.59

LINE1 CpG site−590

77.47

3.71

76.74

3.07

LINE1 CpG site−583

74.27

4.02

71.66

2.33