Table 3 Effect of COMT haplotype on DNA methylation in the whole group. Data is reported as mean (standard error) of both assessments. F-test and p-values refer to the univariate test of the Linear Mixed Model

DNA methylation (%)

High COMT activity

High-intermediate COMT activity

Intermediate COMT activity

Intermediate-low COMT activity

F

p

MB-COMTa

2.79 (0.34)

2.88 (0.18)

2.51 (0.29)

2.52 (0.56)

0.557

0.646

MB-COMTb

1.43 (0.21)

1.80 (0.12)

1.45 (0.19)

1.51 (0.33)

1.73

0.170

MB-COMTc

2.15 (0.36)

2.36 (0.19)

2.30 (0.37)

2.84 (0.56)

0.355

0.785

MB-COMT mean

2.25 (0.27)

2.48 (0.15)

2.21 (0.26)

2.41 (0.41)

0.495

0.687

 S-COMTa

54.42 (1.57)

60.42 (0.74)

66.00 (1.41)

67.43 (2.52)

11.539

< 0.001*

S-COMTb

91.95 (0.64)

93.09 (0.31)

94.80 (0.57)

95.97 (1.01)

5.879

0.001*

S-COMTc

91.71 (0.44)

92.52 (0.22)

92.15 (0.39)

91.47 (0.70)

1.573

0.202

 S-COMT mean

78.21 (0.64)

80.91 (0.30)

83.02 (0.58)

83.54 (1.03)

11.580

< 0.001*