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

Abstract

BackgroundFocusing 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.MethodsAmong 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%).ResultsThe cross-sectional study of the respiratory function test results at the baseline and at the 5th 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.ConclusionOur 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.

A Cohort Study on Respiratory Symptoms and Diseases Caused by Toner-Handling Work: Longitudinal Analyses from 2003 to 2013

“…This suggested that one of the possible reasons the trend in the high prevalence of the subjective symptoms was inconsistent with the objective findings reported in other previous epidemiological studies was the influence of differences between the toner-handling group and the non-toner-handling group at baseline. In terms of the low respiratory toxicity of toner exposure, the results obtained by this cohort study on subjective respiratory symptoms and respiratory diseases showed the same direction as the results of long-term inhalation exposure studies in animals [42][43][44], and objective findings in the previous cohort studies [12][13][14][15].…”

“…Several cohort studies at toner manufacturing factories were conducted for similar purposes to our study [12][13][14][15]. All of these studies consistently reported a tendency for the prevalence of respiratory symptoms, such as cough, phlegm, wheezing, and shortness of breath, to be higher in the toner exposure group, although no significant differences have been found between the toner-handling group and non-toner-handling group.…”

“…Respirable dust collected on the personal dust sampler filters was confirmed to be toner-derived based on electronic microscopy observations and infrared spectroscopy [13]. We found that individual exposure concentrations differed among the five work categories, being significantly higher in machine-recycling work and toner-manufacturing work than in the other work categories.…”

“…Several epidemiological studies have assessed the health effects of toner dust exposure in workers at toner manufacturing factories [12][13][14][15], and suggest the potential adverse effects of inhaling toner dust. However, these previous studies were limited due to sample size, study design, and other factors.…”

Effects of toner-handling work on respiratory function, chest X-ray findings, and biomarkers of inflammation, allergy, and oxidative stress: a prospective Japanese cohort study from 2003 to 2013

“…Several epidemiological cohort studies aimed at investigating the health effects of toner particle exposure have been conducted at toner manufacturing plants [8][9][10][11]. No significant differences were reported between the toner-handling and non-toner-handling groups in terms of the development of new-onset lung fibrosis on follow-up chest X-ray examination.…”