Table 1 Clinical characteristics of study subjects

Male/female

10/2

41/1

0.234

Age (yrs)

40.92 ± 11.49

46.60 ± 5.95

0.063

Smoking pack-years (yrs)

15.00 (2.50, 20.00)

13.50 (4.25, 23.75)

0.742

Years of occupational exposure to silica dust (yrs)

9.56 ± 10.07

15.26 ± 7.75

0.114

BMI

24.19 (20.18, 26.64)

21.76 (20.05, 23.84)

0.213

FVC (l)

3.38 ± 0.52

3.24 ± 0.74

0.725

FVC% pre

87.30 ± 8.16

71.51 ± 14.27

0.037

FEV1 (l)

2.73 ± 0.45

2.33 ± 0.79

0.333

FEV1% pre

85.45 (72.98, 87.20)

60.30 (48.55, 72.98)

0.021

FEV1/FVC (%)

80.22 ± 1.10

69.96 ± 14.21

 < 0.01

Vcmax (l)

3.42 ± 0.54

3.26 ± 0.68

0.642

IC (l)

2.01 ± 0.05

2.09 ± 0.69

0.485

PEF (l/s)

3.88 (2.91, 3.90)

2.95 (2.35, 4.29)

0.416

PEF25 (l/s)

3.88 (2.82, 3.90)

2.81 (2.04, 3.69)

0.214

PEF50 (l/s)

3.48 (2.49, 3.61)

1.98 (1.29, 3.18)

0.123

PEF75 (l/s)

1.42 (1.23, 1.70)

0.97 (0.52, 1.44)

0.072

Stage of silicosis (n, %)

–

Stage I

–

9 (21.43%)

Stage II

–

13 (30.95%)

Stage III

–

20 (47.62%)