Lung Function Status of Some Ethiopians Exposed to Occupational Dusts
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Date
1992-06
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Addis Ababa University
Abstract
Acute and chronic changes of ventilatory capacities and the
prevalences of respiratory symptoms were studied in 233 (117
males and 116 females) nonsmoking factory workers exposed to
cotton, tobacco and cement dusts. Two hundred and thirty six (125
males and 111 females) workers who were nonsmokers and had no
exposure to occupational dusts were taken as non-exposed
subjects. An attempt was made to see values of ventilatory
indices in relation to dust concentration and duration of
exposure. Comparison was also made between dust concentrations
recorded in this study and standards recommended by ACGIH and
WHO. Prevalences of respiratory symptoms (chronic cough, chronic
bronchitis, and bronchial asthma) were found to be higher in all
dust-exposed groups than they were in the non-exposed subjects.
All respiratory symptoms considered in the present study were
found in cement and cotton workers much more frequently than in
the non-exposed sUbjects. Only chronic cough was found to be more
frequent among tobacco workers than among the non-exposed
sUbjects. significant reductions of FVC, FEV1, MMFR and PEFR
values over the workshift were recorded among cotton and tobacco
workers. Acute reductions in cement workers were recorded only in
FVC and PEFR. Significantly reduced mean values of FEV1%, FEF
, MMFR in both sexes of exposed subjects and FEV1 and PEFR in male
Exposed subjects were recorded. After matching of exposed subjects, from
each factory, with the non-exposed subjects according to their
age and height, significantly reduced mean values of FEV1%, FEF,
MMFR in both sexes of cotton workers and PEFR in male cotton
workers were recorded. Mean values of FEVl% and MMFR in cement
workers, FEVl in female tobacco workers and PEFR, MV and MVV in
male tobacco workers were found to be significantly lower than in
the non-exposed sUbjects. Substantial number of workers were
found to have lower values of ventilatory capacities than their
predicted values by more than two standard errors of estimate.
Predicted values of ventilatory indices were calculated for both
sexes by means of multiple linear regression equations, developed
on the basis of data obtained in the non-exposed subjects.
Mean percentages of predicted lung function values in
workers exposed to relatively high dust concentration were found
to be lower than the values observed in those exposed to lower
concentration, but significant differences (in FEVl %) were
observed only in cement workers. strong negative correlations (rS-O.30)
were recorded between duration of exposure and FVC, FEVl , FEV1% and
MMFR values in male exposed subjects. Negative correlations were also
observed among females, but the relationships were not as strong as that of
males. When compared with standards of ACGIH and WHO, the dust
concentrations in cement and yarn factories were found to be
high.
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Biology