Table 6.

Analysis of the health effects of toner exposure with adjustment for confounders (model 4)

Parameters (unit)	Difference in yearly change in each parameter between the low-concentration toner exposure group and non-toner-handling group				Difference in yearly change in each parameter between the high-concentration toner exposure group and non-toner-handling group				Yearly change in each parameter of the non-toner-handling group
	Estimate	95% CI		P-value	Estimate	95% CI		P-value	Estimate	95% CI		P-value	AIC
Respiratory function tests
VC (l)	−0.001	−0.004	0.002	0.378	−0.005	−0.01	0.002	0.159	−0.007	−0.01	− 0.005	< 0.001	− 5278.0
%VC (%)	− 0.03	−0.10	0.03	0.284	−0.2	−0.3	− 0.003	0.045	0.2	0.1	0.2	< 0.001	73,413.9
FEV1 (l)	0.0001	−0.002	0.002	0.954	−0.001	−0.007	0.005	0.824	−0.02	−0.02	− 0.02	< 0.001	− 9973.4
%FEV1 (%)	0.02	−0.05	0.08	0.614	0.01	−0.2	0.2	0.898	0.1	0.09	0.2	< 0.001	74,937.0
FEV1/FVC (%)	0.001	−0.04	0.04	0.964	0.05	−0.05	0.1	0.325	−0.3	−0.3	− 0.3	< 0.001	60,386.6
%FEV1/FVC (%)	0.01	−0.04	0.06	0.670	0.10	−0.02	0.23	0.108	−0.09	−0.1	− 0.05	< 0.001	65,542.2
V25 (l/s)	0.001	−0.003	0.005	0.640	0.002	−0.007	0.01	0.448	−0.03	−0.03	− 0.03	< 0.001	3479.7
%V25 (%)	0.02	−0.2	0.2	0.861	0.2	−0.3	0.6	0.470	−0.4	−0.6	− 0.3	< 0.001	10,1016.2
Biomarkers
CRP (mg/dl)	0.0002	−0.003	0.003	0.876	0.002	−0.005	0.010	0.558	0.0004	−0.2	−0.08	0.717	3589.0
Ig E (IU/ml)	4.9	−1.0	10.7	0.106	3.5	−12.4	19.4	0.206	−1.6	−6.1	3.0	0.500	17,4511.9
8-OHdG/Creatinine (ng/mg)	−0.01	−0.03	0.006	0.898	0.003	−0.04	0.04	0.758	0.033	0.02	0.05	< 0.001	44,987.9

In model 4, dependent variables consisted of the parameters of respiratory function tests and the values of biomarkers. We compared the high-concentration toner exposure group, low-concentration toner exposure group, and non-toner-handling group and adjusted the model using age at baseline, body mass index, smoking, asthma, allergic rhinitis, pneumonia, sinusitis, non-toner-handling work, and organic solvent-handling work as confounding factors

CI confidence interval, AIC Akaike’s Information Criterion, VC vital capacity, %VC percentage of VC to predicted VC value, FEV₁ forced expiratory volume in 1 s, %FEV₁ percentage of FEV₁ to predicted FEV₁ value, FEV₁/FVC percentage of forced expiratory volume in 1 s, %FEV₁/FVC percentage of FEV₁/FVC to predicted FEV₁/FVC value, V25 maximal expiratory flow at 25% forced VC, CRP C-reactive protein, IgE immunoglobulin E, 8-OHdG 8-hydroxy-2′-deoxyguanosine