Table 2 Spearman correlation coefficients (r_S) between total cell number, percentage of neutrophils, total protein and inflammatory markers in induced sputum (values 24 h after all ZnO exposures were considered) with 95% confidence intervals and p-values

Total cell number

[×  10⁵]

0.51*

0.35–0.67

< 0.0001

0.52*

0.37–0.67

< 0.0001

0.44*

0.28–0.61

< 0.0001

0.60*

0.46–0.73

< 0.0001

0.58*

0.45–0.71

< 0.0001

−0.07

-0.26-0.13

0.4931

−0.21*

-0.40- -0.02

0.0315

0.35*

0.18–0.52

0.0002

Neutrophils

[%]

1

0.70*

0.60–0.78

< 0.0001

0.69*

0.58–0.82

< 0.0001

0.81*

0.73–0.89

< 0.0001

0.79*

0.70–0.87

< 0.0001

0.17

-0.02-0.36

0.3120

−0.26*

-0.46- -0.07

0.0008

0.61*

0.48–0.75

< 0.0001

Total protein

[μg/mL]

1

0.85*

0.78–0.92

< 0.0001

0.84*

0.73–0.89

< 0.0001

0.88*

0.82–0.96

< 0.0001

0.34*

0.19–0.50

0.0003

−0.23*

-0.42- -0.04

0.0193

0.56*

0.43–0.70

< 0.0001

IL-8

[pg/mL]

1

0.87*

0.82–0.95

< 0.0001

0.90*

0.85–0.96

< 0.0001

0.37*

0.22–0.52

0.0001

−0.29*

-0.48- - 0.10

0.0046

0.59*

0.47–0.71

< 0.0001

MMP-9

[ng/mL]

1

0.95*

0.94–0.97

< 0.0001

0.24*

0.08–0.40

0.0146

−0.28*

− 0.46- -0.09

0.0046

0.68*

0.58–0.77

< 0.0001

TIMP-1

[ng/mL]

1

0.19*

0.02–0.35

0.0497

−0.33*

-0.41- -0.15

0.0008

0.65*

0.54–0.77

< 0.0001

8-iso-PGF_2α

[pg/mL]

1

0.17

-0.03-0.38

0.0791

0.05

-0.14-0.23

0.6389

Substance P

[pg/mL]

1

−0.24*

-0.44- -0.03

0.0146

IL-6

[pg/mL]

1