Email updates

Keep up to date with the latest news and content from BMC Public Health and BioMed Central.

Open Access Research article

Pulmonary function, respiratory symptoms, and dust exposures among workers engaged in early manufacturing processes of tea: a cohort study

Tzong-Shiun Shieh12, Jui-Jung Chung1, Chung-Jing Wang3, Perng-Jy Tsai2, Yau-Chang Kuo45 and How-Ran Guo2567*

Author Affiliations

1 Department of Family Medicine and Occupational Medicine Center, St. Martin De Porres Hospital, Chia-Yi, Taiwan

2 Department of Environmental and Occupational Health, National Cheng Kung University, Tainan, Taiwan

3 Medical Administration Department, St. Martin De Porres Hospital, Chia-Yi, Taiwan

4 Department of Occupational and Environmental Medicine, National Cheng Kung University, Tainan, Taiwan

5 Department of Occupational and Environmental Medicine, National Cheng Kung University Hospital, Tainan, Taiwan

6 Sustainable Environment Research Center, National Cheng Kung University, Tainan, Taiwan

7 Medical Device Innovation Center, National Cheng Kung University, Tainan, Taiwan

For all author emails, please log on.

BMC Public Health 2012, 12:121  doi:10.1186/1471-2458-12-121

Published: 13 February 2012

Abstract

Background

To evaluate pulmonary function and respiratory symptoms in workers engaged in the early manufacturing processes of tea and to identify the associated factors, we conducted a study in a tea production area in Taiwan.

Methods

We recruited tea workers who engaged in the early manufacturing process in the Mountain Ali area in Taiwan and a comparison group of local office workers who were matched for age, gender, and smoking habits. We performed questionnaire interviews, pulmonary function tests, skin prick tests, and measurement of specific IgE for tea on the participants and assessed tea dust exposures in the tea factories.

Results

The 91 participating tea workers had higher prevalence of respiratory symptoms than the comparison group (32 participants). Among tea workers, ball-rolling workers had the highest prevalence of symptoms and the highest exposures of inhalable dusts. At baseline, tea workers had similar pulmonary functions as the comparison group, but compared to the other tea workers ball-rolling workers had a lower ratio of the 1-second forced expiratory volume to forced vital capacity (FEV1/FVC) and a lower maximal mid-expiratory flow rate expressed as% of the predicted value--MMF (%pred). A total of 58 tea workers participated in the on-site investigation and the cross-shift lung function measurements. We found ball-rolling yielded the highest inhalable dust level, panning yielded the highest respirable dust level, and withering yielded the lowest levels of both dusts. Ball-rolling also yielded the highest coarse fraction (defined as inhalable dusts minus respirable dusts), which represented exposures from nose to tracheobronchial tract. During the shift, we observed significant declines in pulmonary function, especially in ball-rolling workers. Multiple regressions showed that age, height, work tasks, coarse fraction, and number of months working in tea manufacturing each year were independent predictors of certain pulmonary function parameters in tea workers.

Conclusions

Tea workers engaged in early manufacturing processes of tea have higher prevalence of respiratory symptoms and pulmonary function impairment, which might be related to tea dust exposures, especially the coarse fraction.

Keywords:
Tea; Occupational exposure; Pulmonary function tests; Signs and symptoms; Respiratory