A Cohort Study on Self-Reported Respiratory Symptoms of Toner-Handling Workers: Cross-Sectional and Longitudinal Analysis from 2003 to 2008

Table 2

Demographics of subjects at the baseline.

	All subjects	Toner-handling group	Never-toner-handling group	𝑃 value^#
Subjects number	1504	1071	415
Age
mean (SD^##)	38.6 (6.90)	39.0 (7.08)	37.8 (6.29)	<0.01**
Smoking status
Current smoker (%)	731 (49.3%)	541 (50.7%)	190 (45.8%)
Exsmoker (%)	260 (17.5%)	185 (17.3%)	75 (18.1%)	0.22
Never smoker (%)	492 (21.4%)	342 (32.0%)	150 (32.0%)
Morbidity
Asthma (%)	146 (9.8%)	107 (10.0%)	39 (9.4%)	0.77
Allergic rhinitis^### (%)	743 (50.0%)	543 (50.7%)	200 (48.2%)	0.42
Allergic dermatitis^### (%)	318 (21.4%)	231 (21.6%)	87 (21.0%)	0.83
Work history
Handling of organic compounds (%)	254 (17.2%)	240 (22.6%)	14 (3.4%)	<0.01**

^#𝑃 value of Student’s 𝑡-test and chi-square test, ^∗𝑃<0.05 and ^∗∗𝑃<0.01.
##Standard deviation.
###Allergic rhinitis includes pollinosis, and allergic dermatitis includes atopic dermatitis.
18 subjects were excluded from the analysis due to lack of the work history and 1486 subjects were analyzed.
Among 1486 subjects, smoking status of 3 subjects was missed.
Toner-handling workers who engaged in customer service used an alcoholic organic solvent to clean photocopier machines. Toner-handling workers who engaged in toner manufacturing responded that they used organic compounds during toner producing process, but organic compounds were used in the sealed production line and workers were not exposed in steady work.