[Investigation of contact dermatitis caused by hard metal dust]

Objective: To investigate the incidence of contact dermatitis among workers in cemented carbide production enterprises. Methods: From October 1997 to October 2017, an occupational epidemiological survey was conducted on a large-scale cemented carbide production enterprise, and occupational health examinations were conducted for employees. 152 people were exposed to hard metal dust (hard metal raw material dust and alloy dust) . The employees in the work group were contact groups, and 142 employees in the non-dusting operation of the company were in the control group. A detailed retrospective survey of hard metal production workers with contact dermatitis history in the two groups was conducted to analyze the risk factors of contact dermatitis exposure to hard metal dust. Results: The incidence of allergic diseases in the exposed group was significantly higher than that in the control group. The difference was statistically significant (χ(2)=23.793, P<0.05) . The incidence of contact dermatitis in the exposed group was significantly higher than that in the control group. The difference was statistically significant (χ(2)=24.659, P<0.05) ; the changes of contact dermatitis in the contact group were mainly allergic contact dermatitis, and some showed irritative contact dermatitis; the operator had respiratory symptoms (including work-related nasal congestion, cough, wheezing) , difficulty breathing may be the influencing factors of contact dermatitis (RR=2.60, 95%CI: 1.10-6.20, P<0.05) . Conclusion: Hard metal alloy enterprises are exposed to hard metal dust. The incidence of contact dermatitis is high in workers, and the occurrence of contact dermatitis may be associated with those with respiratory symptoms.