A Case-crossover Study on Mechanical Injuries in Chemical Industry

Objective To study potential risk factors of mechanical injuries in chemical industry and the intensity of these factors.Methods The case crossover design was used.Injured workers were interviewed within 2 days after got injured.Exposure information on potential risk factors at 10 minutes before the injury,the same period in previous working day and a week before was collected.Matched time interval approach and general frequency analysis were used to evaluate these factors.Results In general frequency analysis,instantaneous risk factors such as violation of operating procedure,malfunction of equipment,stress or work pressure,being distracted,without protective equipment,loss of spirit,coordinating badly with colleague and change of work environment were evaluated.All of their relative risks and lower limit of 95% CI were more than 1.In matched time interval analysis,results were similar to the above,except for much wider confidence intervals.Conclusions In chemical industry,the occurrence of occupational mechanical injuries could be related to many risk factors mentioned above.Compared with matched time interval approach,the general frequency analysis showed higher reliability and efficiency.It is suggested that the multiple interval approach should be used for further research to reduce biases of confounding factors.