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. 2020 Sep 29;17:47. doi: 10.1186/s12989-020-00378-8

Table 4.

Mediation effect of TNF-α, IL-1β, and IL-6 on individual biosensor genes in 106 non-CBPs and 82 CBPsa

Biosensor Variable IQR in
non-CBPs		 Factor – biosensor associationa Carbon black – biosensor associationa Mediation effectb
Estimate (SE) P Estimate (SE) P PM Pperm
ICAM Carbon black exposure −0.392 (0.168) (c)c 0.021
TNF-α (pg/ml) 94.3 −0.229 (0.069) (b) 0.0011 0.025 (0.206) (c’) 0.903 1.00 0.006
IL-1β (pg/ml) 6.2 −0.154 (0.023) (b) < 0.0001 −0.184 (0.154) (c’) 0.235 0.53 0.004
IL-6 (pg/ml) 52.1 −0.076 (0.034) (b) 0.029 −0.143 (0.201) (c’) 0.478 0.64 0.05
CRP (mg/L) 0.75 −0.028 (0.024) (b) 0.243 −0.338 (0.174) (c’) 0.054 NM
MIP-1β (ng/ml) 1.05 −0.065 (0.038) (b) 0.083 −0.231 (0.191) (c’) 0.230 NM
VCAM Carbon black exposure −0.689 (0.227) (c)c 0.0027
TNF-α (pg/ml) 94.3 −0.313 (0.093) (b) 0.0009 −0.120 (0.278) (c’) 0.667 0.83 0.004
IL-1β (pg/ml) 6.2 −0.016 (0.035) (b) 0.639 −0.667 (0.232) (c’) 0.0045 NM
IL-6 (pg/ml) 52.1 −0.123 (0.046) (b) 0.008 −0.282 (0.270) (c’) 0.297 0.59 0.038
CRP (mg/L) 0.75 −0.063 (0.032) (b) 0.050 −0.566 (0.234) (c’) 0.016 0.18 0.092
MIP-1β (ng/ml) 1.05 −0.083 (0.051) (b) 0.104 −0.484 (0.258) (c’) 0.062 NM
CCL2 Carbon black exposure −0.567 (0.221) (c)c 0.011
TNF-α (pg/ml) 94.3 −0.319 (0.090) (b) 0.0005 0.014 (0.270) (c’) 0.959 1.00 0.004
IL-1β (pg/ml) 6.2 0.000072 (0.034) (b) 0.998 −0.567 (0.226) (c’) 0.013 NM
IL-6 (pg/ml) 52.1 −0.082 (0.045) (b) 0.073 −0.298 (0.265) (c’) 0.264 0.47 0.068
CRP (mg/L) 0.75 −0.031 (0.031) (b) 0.319 −0.505 (0.229) (c’) 0.0287 NM
MIP-1β (ng/ml) 1.05 −0.061 (0.050) (b) 0.223 −0.417 (0.252) (c’) 0.100 NM
CXCL8 Carbon black exposure −3.181 (0.421) (c)c < 0.0001
TNF-α (pg/ml) 94.3 −0.751 (0.168) (b) < 0.0001 −1.814 (0.504) (c’) 0.0004 0.43 < 0.002
IL-1β (pg/ml) 6.2 −0.039 (0.064) (b) 0.550 −3.129 (0.430) (c’) < 0.0001 NM
IL-6 (pg/ml) 52.1 −0.347 (0.083) (b) < 0.0001 −2.038 (0.487) (c’) < 0.0001 0.36 < 0.002
CRP (mg/L) 0.75 −0.070 (0.059) (b) 0.240 −3.044 (0.436) (c’) < 0.0001 NM
MIP-1β (ng/ml) 1.05 −0.311 (0.092) (b) 0.0009 −2.418 (0.468) (c’) < 0.0001 0.24 0.006
CCL5 Carbon black exposure −0.479 (0.145) (c)c 0.0012
TNF-α (pg/ml) 94.3 −0.268 (0.058) (b) < 0.0001 0.008 (0.174) (c’) 0.963 1.00 < 0.002
IL-1β (pg/ml) 6.2 −0.061 (0.022) (b) 0.0057 −0.397 (0.146) (c’) 0.0071 0.17 0.01
IL-6 (pg/ml) 52.1 −0.069 (0.030) (b) 0.020 −0.251 (0.174) (c’) 0.150 0.48 0.01
CRP (mg/L) 0.75 −0.039 (0.020) (b) 0.054 −0.402 (0.150) (c’) 0.008 0.16 0.056
MIP-1β (ng/ml) 1.05 −0.104 (0.032) (b) 0.0014 −0.224 (0.162) (c’) 0.168 0.53 0.002

CBP Carbon black packer, IQR Inter-quartile range, SE Standard error, GLM Generalized linear model

aGLM was used to assess the association (c’) between carbon black exposure and delta Ct of selected biosensor genes with age, overweight and obesity, current smoking status, packyears, passage of cells, and cytokines or chemokines (b) included as covariate for adjustment. Non-transformed data of cytokine and chemokine levels were used in GLM. c’ and b should be referred to Fig. 1

bThe proportion mediated effect size that quantifies the proportion of a total effect mediated was calculated using the following equation: (c-c’) / c. The database was permuted for 500 times to generate a null distribution of c-c’. Pperm was calculated as the number of permuted databases generating a c-c’ that is less than observed value divided by 500. c should be referred to Fig. 1

cGLM was used to assess the association between carbon black and delta Ct of selected biosensor genes in 106 non-CBPs and 82 CBPs with adjustment for age, overweight and obesity, current smoking status, and packyears, and passage of cells. c should be referred to Fig. 1