Respiratory impairment, prevalence, quarry workers, control group


OBJECTIVE: To determine the prevalence of respiratory impairment among quarry workers in a particular state in South-South Nigeria.
METHODOLOGY: This study was conducted among workers in a quarry industry as cases and control selected among junior staffs of a tertiary institution in the state who were not directly exposed to dust as part of job description. A cross-sectional analytical study design was utilized for the study. The minimum sample size for the study was calculated using the Cochrane formula for minimum sample size determination in a descriptive cross-sectional study. Total population of quarry workers were used as cases and same number of cases used as control. The instrument used included validated semi-structured respiratory questionnaires, stadiometer, spirometer and a dust meter. Data entering and analysis were done using IBM-SPSS version 20.0 software. Results were presented in tables and frequency. Test of association such as chi-square and fisher’s exact was utilized where appropriate. Statistical significance was set at p <0.05
RESULTS: The mean age of the quarry workers was 40.54±10.32 while that of the control group was 34.40±10.00 with most of the respondents in both groups being males. Forty seven point seven percent (47.7%) of the respondents among the quarry workers were drillers, 23.4% plant operators, 7.1% shot firers, and 2.4% pay-loaders. The mean Percentage predicted FVC for quarry workers was 71.84±14.20% while that of the control group was 85.39±12.52%. The mean percentage predicted FEV1 for quarry workers and control group were 79.40±12.73% and 89.46±31.24% respectively. Majority of the quarry workers (78.8%) had lung impairment and were seven times more likely to have lung impairment as compared to the control group. Seventeen point five percent (17.5%) of quarry workers had moderate impairment and 0.2% had severe impairment while 0.5% of the control group had moderate impairment with none having severe lung impairment.
CONCLUSION: The prevalence of respiratory impairment among the quarry workers studied was very high with overall prevalence rate of 78.8% when compared to the control group. Among the quarry workers, the prevalence of moderate lung impairment was 17.5% while severe impairment was 0.2%. The prevalence of moderate impairment among the control group was 0.5% while none of the control had severe lung impairment