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Table 4 Correlation of inflammatory markers with exposure using Pearson’s r or Kendall \(\uptau\) statistics

From: Occupational quartz and particle exposure affect systemic levels of inflammatory markers related to inflammasome activation and cardiovascular disease

Inflammatory markers

Sample data

Exposure

Pearson's r

Kendall \(\uptau\)

Caspase-1 ex vivo activation in monocytes

  

r

P-value

\(\uptau\)

P-value

Caspase-1, LPS activated

Morning \(\overline{\times }\) 1st, 2nd

Resp. dust

-0.55

2.65 × 10–4

-0.34

0.0021

Morning 2nd

Resp. dust

-0.60

2.56 × 10–4

-0.43

6.20 × 10–4

Morning 2nd

Resp. quartz

  

-0.40

0.0016

Caspase-1, ATP activated

Morning \(\overline{\times }\) 1st, 2nd

Resp. quartz

-0.41

0.0089

  

Morning 2nd

Resp. quartz

-0.59

4.35 × 10–4

  

Shift difference

Resp. dust

0.40

7.69 × 10–4

0.28

0.0011

Shift difference

Resp. quartz

0.39

0.0012

0.26

0.0027

Caspase-1, LPS + ATP activated

Morning \(\overline{\times }\) 1st, 2nd

Resp. quartz

-0.48

0.0019

-0.30

0.0075

Morning 2nd

Resp. quartz

-0.66

3.31 × 10–5

-0.45

2.98 × 10–4

Inflammatory mediators

 CXCL8

Morning 2nd

Resp. dust

0.36

0.0045

  

 SAA

Shift difference

Resp. dust

  

-0.22

0.0087

Shift difference

Resp. quartz

  

-0.27

0.0014

 sST2

Morning 2nd

Resp. quartz

-0.55

0.0010

-0.38

0.0022

  1. The inflammatory markers with a significant correlation to respirable dust and/or quartz are shown (p < 0.01). The full list of studied inflammatory markers is found in Fig. 3. Over-shift differences in inflammatory markers are used as a measure of effects from current days exposure, whereas the morning samples are used as a measure of effects from recent days/weeks of exposure, assuming similar exposures as measured for the time period between the first and second measurement. Morning \(\overline{\times }\) 1st, 2nd: the average inflammatory marker and exposure level from the two sampling occasions for each participant. Morning 2nd: The morning inflammatory marker levels of the second measurement (follow-up measurement) correlated to the averaged exposure level for the two sampling measures
  2. LPS Lipopolysaccharide, ATP Adenosine triphosphate, resp. Respirable