Table 2 Mitochondrial DNA methylation level (%) by exposure groups of airborne pollutants

MT-TF & MT-RNR1

6.47% ± 0.29

5.06% ± 0.30

0.002

D-loop

2.16% ± 0.17

2.18% ± 0.17

0.93

Study 2

Gas-station attendants (n = 20)

Controls (n = 20)

p-value

MT-TF & MT-RNR1

5.52% ± 0.22

5.89% ± 0.23

0.22

D-loop

1.68% ± 0.16

1.55% ± 0.16

0.53

Study 3

Truck drivers (n = 20)

Controls (n = 20)

p-value

MT-TF & MT-RNR1

5.37% ± 0.22

5.41% ± 0.22

0.88

D-loop

2.46% ± 0.54

2.38% ± 0.53

0.82