Table 2.

Associations between exposure and relative mtDNA copy number, D-loop and MT-TF methylation in adjusted models^a

	mtDNA copy number			D-loop methylation			MT-TF methylation
	N	Beta (95% CI)	p	N	Beta (95% CI)	p	N	Beta (95% CI)	p
Occupational group
Welders vs. controlsb	228	0.11 (0.037, 0.18)	0.0032	211	−1.4 (−2.3, −0.5)	0.0021	220	−1.5 (−2.5, −0.48)	0.0038
Exposure level
Respirable dustc	101	0.017 (−0.018, 0.052)	0.33	92	0.012 (−0.47, 0.50)	0.96	97	0.097 (−0.32, 0.51)	0.64
Respirable dust (<=0.7 mg/m3)c, d	57	−0.031 (−0.47, 0.41)	0.89	54	−0.42 (−4.76, 3.9)	0.85	56	2.9 (−2.2, 8.1)	0.26
Respirable dust (>0.7 mg/m3)c, d	41	0.037 (−0.00075, 0.075)	0.054	38	−0.043 (−0.85, 0.76)	0.92	41	0.17 (−0.29, 0.63)	0.46
Working yearse	100	−0.0027 (−0.010, 0.0049)	0.49	93	0.061 (−0.053, 0.16)	0.29	99	−0.013 (−0.10, 0.076)	0.77

^aThe adjusted model included age, BMI, previous smoking years, smokeless tobacco “snus” status and current residence as adjustments

^bEffect estimates presented are β-values for occupation (welders compared with control) derived from general linear models

^cEffect estimates presented are β-values for personal respirable dust (only welders included) derived from general linear models

^dThe cut-off was based on median value of welders with measured and estimated respirable dust

^eEffect estimates presented are β-values for years working as welder (only welders included) derived from general linear models