Abstract:
Objectives To determine the prevalence of silicosis among the in-service
Zambian copper miners and identify which areas of operations and mines are
mostly affected by silicosis.
Design: Cross-sectional point prevalence.
Setting: Medical records of miners from Occupational Health Research
Bureau Kitwe-Zambia.
Subjects and methods: 1122 miners who had worked for more than ten
years in the scheduled area were randomly selected for the study from the
Bureau records. Data was analyzed in Stata for descriptive summaries
associations of silicosis with and independent variables.
Results: The prevalence of silicosis was 8 per 1000 miners with Chibuluma
mine recording the highest prevalence2.2%(1 out of 27) and with the dust
producing areas recording the highest prevalence 6 out of the 9 cases
(66.6% ). All the cases were from underground miners and were above 40
years of age. Silicosis was strongly associated with years of service, age of
the miners and area of operations (p <0.05). Association was shown between
silicosis and dust particles in chi-square test of association, but when put in
binary logistic regression there was no association (p 0. 7) probably because
dust particle levels was used instead of respirable free silica and the different
mines contain different silica levels in their virgin rocks. If respirable free silica
levels were used the association could have been there. This can be
confirmed by the high prevalence in dust producing areas.
Conclusion: The prevalence of silicosis among the in-service Zambia copper
mines is low compared to other mining countries. There is a possibility of high
prevalence among the retirees since all of them are more than 40years of age
and there is strong association between years of service age, and areas of
operation with silicosis.
