Epidemiology of Respiratory Symptoms and Changes in Biological Parameters Over 5 Years in Japanese Workers Engaged in Toner Manufacturing

Abstract

PP-30-207 Background/Aims: After some cases of siderosilicosis caused by toner were reported in the Lancet in 1994, some further studies reported granulomatous pneumonitis due to toner. However, few epidemiological studies discussing the effects of toner exposure on human health have been reported. This study aims to examine the relationship between work that involves exposure to printer/copying machine toner and development of respiratory disorders. Methods: A total of 1504 male workers between 19 and 50 years were selected from workers engaged in production of supplying materials, including toner in Japan. Subjects were divided into 2 groups: 768 subjects with exposure to toner via toner manufacturing and development, machine development, production and maintenance, and recycle process; and 736 nonexposed referents. In addition to annual health check, toner exposed state, respiratory symptoms, and various biological parameters such as pulmonary function and biochemical markers were examined. This report describes the annual results of a cross-sectional analysis and longitudinal survey for first 5 years. Results: Cross-sectional analysis showed significantly higher prevalence of respiratory symptoms in toner-exposed workers than nonexposed workers. In the longitudinal study, regarding the prevalence rate of most respiratory symptoms, especially acute or mild symptoms, difference between the 2 groups reduced year-on-year and the number of items that showed significant difference declined. Pulmonary function, blood cells, and biochemical markers did not consistently prove that tendency depends on toner exposure over the first 5 years. Conclusion: In this study conducted over 5 years, it became clear that exposure to toner did not result in clear harmful effects, but harmful effects caused by smoking on respiratory function, blood cells, and biochemical markers were much stronger. However, since difference in prevalence of respiratory symptoms might be due to information bias, to truly shed light on the effects of toner-exposure, it is important to continue the current 10-year cohort study.