Airflow limitation among workers in a labour-intensive coal mine in Tanzania.
Loading...
Date
2007-01-23
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
International archives of occupational and environmental health
Abstract
Objectives To describe the relationship between
cumulative respirable dust and quartz exposure and
lung functioning among workers in a labour-intensive
coal mine.
Methods The study population comprised 299 men
working at a coal mine in Tanzania. Lung function was
assessed using a Vitalograph alpha III spirometer in
accordance with American Thoracic Society recommendations. Multiple linear regression models were
developed to study the relationship between forced
expiratory volume in 1 s (FEV1), forced vital capacity
(FVC) and FEV1/FVC and the cumulative dust or
quartz exposure while adjusting for age, height and ever
smoking. To evaluate trends for dose response, cumulative exposure concentrations for respirable dust and
quartz were ranked and categorized in quartiles and the
highest decile, with the first quartile as the reference
group. Logistic regression models were used to determine odds ratios for FEV1/FVC < 0.7 and FEV1% < 80
for categories of cumulative dust or quartz exposure.
Results The prevalence of FEV1/FVC < 0.7 among the
workers was 17.3%. Workers in the development team
(20.5%) had the highest prevalence of FEV1% < 80%.
The estimates of the effects of cumulative exposure on
FEV1/FVC were –0.015% per mg years m–3 for respirable dust and –0.3% per mg years m–3 for respirable
quartz. In logistic regression models, the odds ratios for
airway limitation (FEV1/FVC < 0.7) for the workers in
the highest decile of cumulative dust and quartz exposure versus the referents were 4.36 (95% confidence
interval: 1.06, 17.96) and 3.49 (0.92, 13.21), respectively.
The upper 10% of workers by cumulative dust and
quartz exposure also had higher odds ratios for predicted
FEV1% < 80% than the reference group odds ratio:
10.38 (1.38, 78.13) and 14.18 (1.72, 116.59), respectively.
The results must be interpreted with caution due to a
possible healthy worker effect and selection bias.
Conclusion Exposure to respirable coal mine dust was
associated with airway limitation as measured by FEV1/
FVC and predicted FEV1%.
Description
Keywords
Lung functioning tests, Coal mining, Quartz
Citation
Mamuya, S.H., Bråtveit, M., Mashalla, Y.J. and Moen, B.E., 2007. Airflow limitation among workers in a labour-intensive coal mine in Tanzania. International archives of occupational and environmental health, 80(7), pp.567-575.