Chronic Respiratory Symptoms Among Workers at a Limestone Factory in Zambia

ABSTRACT

Limestone processing is a global industry, but few studies have assessed respiratory health among limestone workers. At a limestone factory in Zambia, the authors studied 70 high-exposed workers from the production department, 40 medium-exposed from engineering, and 30 low-exposed from administration. A modified British Medical Research Council respiratory questionnaire was used for recording chronic respiratory symptoms. The prevalence of symptoms was highest among the production workers. After adjusting for age, smoking, previous jobs, and past respiratory diseases, the production workers still had a significantly increased relative risk for cough day and night, cough 4 to 6 times daily in a month, and cough with sputum. The results indicate that exposure to limestone dust is associated with increased prevalence of respiratory symptoms. Until newer technology is installed, proper use of personal protective equipments should be emphasized.

KEYWORDS:

• dust exposure
• limestone
• respiratory symptoms

Acknowledgments

The authors are grateful to the management and the workers at the limestone factory for their help in performing the study. This work was supported by the Norwegian State Education Loan Fund (Lånekassen) and the Norwegian Programme for Development, Research and Education (NUFU).

Notes

^a Pearson's chi-square test (or Fisher's exact test). *p < .05; **p < .01; ***p < .001; ns, not significant.

^a Relative risk and 95% confidence interval adjusted for age, past respiratory diseases, previous work in dusty industries, and current smoking.

^b Pearson's chi-square test (or Fisher's exact test); compared to low exposed group. *p < .05; **p < .01; ***p < .001; ns, not significant.

^c Relative risk not calculated due to low numbers in the reference category.