Basic Study
Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Respirol. Mar 28, 2016; 6(1): 24-32
Published online Mar 28, 2016. doi: 10.5320/wjr.v6.i1.24
Pulmonary effects of intermittent, seasonal exposure to high concentrations of cotton dust
Masoud Neghab, Esmaeel Soleimani, Morteza Nowroozi-Sarjoeye
Masoud Neghab, Research Center for Health Sciences, Shiraz University of Medical Sciences, Shiraz 71645, Iran
Esmaeel Soleimani, Morteza Nowroozi-Sarjoeye, Student’s Research Committee, School of Health, Shiraz University of Medical Sciences, Shiraz 71645, Iran
Author contributions: Neghab M and Nowroozi-Sarjoye M substantially contributed to the conception and design of the study, acquisition, analysis and interpretation of data; Neghab M, Soleimani E and Nowroozi-Sarjoye M drafted the article and made critical revisions related to the intellectual content of the manuscript, and approved the final version of the article to be published.
Supported by Shiraz University of Medical Sciences, Vice chancellor for research and technology, No. 91-6347.
Institutional review board statement: All participants signed an informed consent form before participation in the study. The protocol of the study was approved by the University Ethics Committee.
Institutional animal care and use committee statement: Not applicable.
Conflict-of-interest statement: No conflict of interest exist whatsoever.
Data sharing statement: The data referred to in this manuscript have been generated solely by the authors. No other party has been involved. Therefore, the issue of data sharing is not applicable here.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Morteza Nowroozi-Sarjoeye, Student’s Research Committee, School of Health, Shiraz University of Medical Sciences, PO Box 111, Shiraz 71645, Iran. nowroozi.morteza@gmail.com
Telephone: +98-713-7251020 Fax: +98-713-7260225
Received: May 23, 2015
Peer-review started: May 23, 2015
First decision: August 14, 2015
Revised: September 9, 2015
Accepted: November 17, 2015
Article in press: November 17, 2015
Published online: March 28, 2016
Processing time: 307 Days and 12.5 Hours
Abstract

AIM: To quantify the exposure levels and to assess pulmonary reactions associated with exposure to cotton dust and its biological contaminants.

METHODS: All employees (51 male workers) of a ginning industry as well as 51 referent unexposed subjects from clerical staff of an educational center were investigated. Atmospheric concentrations of cotton dust and bioaerosols were measured. Furthermore, bacterial and fungal genera and species were identified by an expert microbiologist and an experienced mycologist. A standard respiratory symptom questionnaire was filled out for the subjects and they underwent multiple spirometry tests, at the beginning and at the end of work season as well as prior to (pre-exposure base line values) and at end of the first shift of workweek (post exposure).

RESULTS: Gram negative bacteria including Enterobacter agglomerans and Pseudomonas spp. were found to be the dominant bacterial species and genera, respectively. Similarly, dominant fungi were identified to be Mucor sp. Rhizopus sp. and Aspergillus niger. Mean atmospheric concentrations of cotton dust in ginning and outdoor areas were found to be 35.2 and 6.8 mg/m3, respectively. The prevalence rates of cough, phlegm, wheezing, dyspenea and grade 1/2 byssinosis among the exposed subjects were significantly higher than their corresponding values for the unexposed employees (P < 0.05). Additionally, significant differences were noted in the mean baseline value (preshift) of vital capacity, forced expiratory volume in the first second (FEV1) and FEV1/forced vital capacity ratio of the exposed subjects when compared with those of their referent counterparts. Similarly, significant cross shift decrements were noted in most parameters of pulmonary function of the exposed subjects.

CONCLUSION: Seasonal exposure to cotton dust induces both acute, partially reversible, and chronic irreversible decrements in the lungs’ functional capacities as well as increased prevalence of respiratory symptoms.

Keywords: Cotton dust; Bioaerosols; Byssinosis; Lungs’ functional impairments; Respiratory symptoms

Core tip: It is not known whether long term seasonal exposure to high concentrations of cotton dust for a few months per year followed by several months of exposure free period in ginning industry is associated with any pulmonary effects. Findings of the present study indicate that even seasonal exposure to high concentrations of this organic dust is a risk factor for byssinosis manifested by acute partially reversible and chronic irreversible significant decrements in lungs’ functional capacities and increased prevalence of respiratory symptoms.