A 4-Year Follow-up Cohort Study of the Respiratory Functions in Toner-handling Workers

BACKGROUND Focusing on the respiratory function for health effect indices, we conducted a cross-sectional study on workers who did and did not handle toner to compare the longitudinal changes. METHODS Among 116 individuals who worked for a Japanese business equipment manufacturer and participated in the study, the analysis included 69 male workers who we were able to follow up for 4 years. We categorized the 40 workers engaged in toner-handling work as the exposed group and the 29 workers not engaged in these tasks as the referent group, and compared their respiratory function test results: peak expiratory flow rate (PEFR), vital capacity (VC), predicted vital capacity (%VC), forced expiratory volume in 1 second (FEV1), and forced expiratory volume in 1 second as a percent of forced vital capacity (FEV1%). RESULTS The cross-sectional study of the respiratory function test results at the baseline and at the 5(th) year showed no statistically significant differences in PEFR, VC, %VC, FEV1, and FEV1% between the exposed and referent workers. Also, respiratory function time-course for 4 years was calculated and compared between the groups. No statistically significant differences were shown. CONCLUSION Our study does not suggest any toner exposure effects on respiratory function. However, the number of subjects was small in our study; studies of larger populations will be desired in the future.