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Table 1 Basic characteristics and mitochondrial DNA biomarkers in welders (n = 101) and controls (n = 127)

From: Occupational exposure to particles and mitochondrial DNA - relevance for blood pressure

 

Welder

Control

p g

Agea

41 (23 – 60)

43 (23 – 56)

0.94

BMI (kg/m2)a

28 (22 – 34)

27 (22 – 34)

0.70

Respirable dust (mg/m3)a,b

1.1 (0.2 – 8.4)

0.1 (0.0 – 0.1)

<0.001h

Working years as welder (year)a

15 (1 – 38)

---

--

Systolic blood pressure (mm Hg)a

130 (115 – 155)

125 (105 – 145)

<0.001

Diastolic blood pressure (mm Hg)a

75 (60 – 85)

70 (60 – 85)

<0.001

Previous smoking (yes/no (%))

43/58 (43%)

43/83 (34%)

0.21i

Previous smoking years (year)a

10 (3 – 32)

14 (2 – 31)

0.52

Smokeless tobacco “snus” (yes/no (%))

28/73 (28%)

24/103 (19%)

0.15i

Relative mtDNA copy numbera

1.13 (0.84 – 1.52)

1.00 (0.74 – 1.50)

0.0049

D-loop methylationa, c

13.4 (10.5 –20.8)

15.6 (10.9 – 21.1)

0.0012

MT-TF methylationa, c

3.4 (0 – 9.5)

4.5 (0 – 12.1)

0.0015

mtDNA function group (high/low (%)) (D-loop)d, f

57/37 (60%)

51/66 (44%)

0.026i

mtDNA function group (high/low (%)) (MT-TF)e, f

63/37 (63%)

47/73 (39%)

<0.001i

  1. aPresented as median (5 – 95 percentile)
  2. bMedian of respirable dust in welder group was based on 70 welders with measured respirable dust
  3. cMedian of D-loop methylation was based on 211 participants (94 welders and 117 controls); median of MT-TF methylation was based on 220 participants (100 welders and 120 controls)
  4. dDerived from unmethylated D-loop and relative mtDNA copy number: Relative number of unmethylated D-loop = (100% - % methylated D-loop) × relative mtDNA copy number
  5. eDerived from unmethylated MT-TF and relative mtDNA copy number: Relative number of unmethylated MT-TF = (100% - % methylated MT-TF) × relative mtDNA copy number
  6. fStratified into low and high groups based on the median. Here, we present the count (%) of participants in each function group
  7. g p value obtained from t test unless marked otherwise
  8. h p values obtained from Mann–Whitney U test
  9. i p values obtained from Fisher’s exact test