A comparison of the cumulative frequency of incidence in select biomedical indices associated with lung fibrotic changes that newly emerged during the follow-up period
| Univariate analysis | P values* | Multivariate analysis | |||||
| Incidence | Logistic regression model | ||||||
| Total | Total | TPD | DDM | MTN | |||
| Exposed | Controls | OR (95% CI)† | OR (95% CI)† | OR (95% CI)† | OR (95% CI)† | ||
| Respiratory symptoms‡ | |||||||
| Chronic cough (7E) | 11.3 | 6.3 | 0.04 | 2.26 (1.13 to 4.53) | 1.88 (0.82 to 4.31) | 2.70 (1.21 to 5.99) | 2.31 (1.01 to 5.25) |
| Chronic phlegm (8E) | 14 | 9.6 | 0.12 | 1.6 (0.91 to 2.83) | 1.46 (0.74 to 2.88) | 1.65 (0.81 to 3.37) | 1.68 (0.83 to 3.40) |
| Breathlessness #2 (13B) | 6 | 4.7 | 0.48 | 1.69 (0.73 to 3.94) | 1.51 (0.54 to 4.19) | 0.94 (0.27 to 3.25) | 2.62 (1.00 to 6.87) |
| Serum biomarkers | |||||||
| KL6§ | 2.1 | 1.8 | 1 | 1.27 (0.38 to 4.29) | 2.09 (0.54 to 8.05) | 0.44 (0.05 to 4.09) | 1.25 (0.26 to 5.94) |
| SPD | 2.4 | 2.4 | 1 | 1.06 (0.34 to 3.28) | 0.87 (0.21 to 3.54) | 1.62 (0.40 to 6.48) | 0.94 (0.21 to 4.24) |
| Pulmonary function | |||||||
| FVC | 15.3 | 13.2 | 0.5 | 1.22 (0.73 to 2.05) | 2.60 (1.44 to 4.71) | 0.54 (0.24 to 1.21) | 0.84 (0.42 to 1.68) |
| FEV1 | 11.4 | 8.5 | 0.26 | 1.38 (0.76 to 2.49) | 2.43 (1.24 to 4.76) | 0.68 (0.27 to 1.69) | 1.19 (0.55 to 2.57) |
| FEV1/FVC | 9.9 | 6.8 | 0.2 | 1.59 (0.81 to 3.09) | 1.88 (0.87 to 4.09) | 1.16 (0.48 to 2.85) | 1.72 (0.77 to 3.85) |
| Chest X- ray | |||||||
| Non-specific findings | 5.6 | 5.2 | 0.8 | 1.39 (0.65 to 2.97) | 1.38 (0.53 to 3.59) | 1.75 (0.70 to 4.37) | 0.98 (0.34 to 2.80) |
The figures in the column of incidence represent the proportion of subjects starting to show symptoms or positive findings during the follow-up period among those who did not have the symptom or positive finding at baseline. The results of multivariate analyses were adjusted for the age and smoking status of the subjects.
*Probability under the hypothesis that there are no differences between the control group and exposed group as a whole examined by the χ2 test or Fisher’s exact probability method.
†OR and its 95% CIs of the exposed group to the control group, regarding the newly emerging abnormalities of biomedical indices.
‡The ATS-DLD-78A questionnaire code is shown in the parentheses.
§Fisher’s exact probability method was applied.
#Grade of the severity of the symptom.
ATS, American Thoracic Society; DDM, machine design and development; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; KL6, sialylated carbohydrate antigen KL-6; MTN, maintenance; RCL, recycling; SPD, surfactant protein D; TPD, toner production.