Research On Contact Skin Injury In Metal Machinery Manufacturing And Processing Industry

Background:In recent years, the prevalence rates of contact skin injury have been high in researches from many countries. And it is an urgent occupational health problem which not only affects workers'physical and mental health but also causes sever loss in social economical development. Workers in metal machinery manufacturing and processing industry are listed as one of the high risk population of contact skin injury. Therefore, researches on prevalence and related risk factors of contact skin injury in this population are greatly important for contact skin injury control and prevention.Objectives:(1) To investigate prevalence and distribution of contact skin injury of workers in metal machinery manufacturing and processing industry;(2) To explore occupational hazard factors of contact skin injury of workers in metal machinery manufacturing and processing industry; (3) To explore related personal protective measure and its effectiveness on contact skin injury in metal machinery manufacturing and processing industry; (4) To provide basis for further intervention researches.Methods:Cross-sectional study and retrospective study are conducted for enterprise survey and personal survey in 11 metal machinery manufacturing and processing enterprises from September 2008 to September 2009. Homemade enterprise questionnaires and revised Nordic Occupational Skin Questionnaire are administrated for enterprises and workers respectively. The study includes manufacturing technique, occupational hazard factors and their distribution, arrangement of personal protective equipment, the prevalence and its related factors, and protective status in workers.Results:2420 questionnaires were delivered,1964 (81.6%) questionnaires were retrieved, and 1885 were valid. (1) The prevalence rate of eczema both on hand and wrist or forearm was 7.5% in workers of metal machinery manufacturing and processing industry. The confirm rate was 24.1% after diagnosis in workers who self-reported having contact skin injury. The prevalence rate of hand eczema was highest in workers of water pump manufacture enterprises, which was 37.8%, and its rate of eczema on wrist or forearm was 29.3%. The rate of hand eczema in workers of mobile phone shell manufacture enterprises was lowest, which was 2.3%, and its rate of eczema on wrist or forearm was 0.4%. The top five working procedures of highest prevalence rate of eczema in turn were heat treatment, modeling, metal melting, assembling and spray-painting(hand eczema) or sand stripping(eczema on wrist or forearm). The prevalence rate of eczema was statistically higher in workers aged 32 or more than those aged less than 32. The prevalence rate of hand eczema was highest in workers with 16-20 years'working age, which was 20.7%; the rate of eczema on wrist or forearm was highest in workers with 26-30 years' working age, which was 19.0%. It was lowest in those worked 0-5 years (hand eczema:7.9%, eczema on wrist or forearm:5.3%). And it was higher in male workers than in female workers. (2) The main occupational hazard factors causing contact skin injury were dust in mold casting, metal processing fluid, epoxide resin, benzene and its homologues, formaldehyde and high temperature. And the main occupational hazard factors leading contact skin injury to aggravate were dust in mold casting, benzene and its homologues, strong acid or strong base, epoxide resin, heavy metal (manganese and its chemical compounds, oxides of chromium and nickel) and synthetic detergent. Univariate analysis indicated that sensitive skin and allergic history of skin were statistically significant, and they might increase the risk of eczema. In multivariate logistic analysis, the factors associated with hand eczema were male, aged 32 or more, allergic history of skin, history of asthma, sensitive skin, and those factors except male were also associated with eczema on wrist or forearm. (3) In the aspect of personal protective equipment, wearing protective gloves or not was not statistically associated with eczema. Although enterprises have arranged personal protective equipment for corresponding working procedures, they haven't arrange correct and proper personal protective equipment according to regulation of personal protective equipment selection (GB/T 11651-2008).Conclusion:(1) The prevalence rate of eczema on hand and wrist or forearm was high in workers of metal machinery manufacturing and processing industry. And it was highest in workers of water pump manufacture enterprises. The top five working procedures of highest prevalence rate of eczema in turn were heat treatment, modeling, metal melting, assembling and spray-painting(hand eczema) or sand stripping(eczema on wrist or forearm). (2) Occupational hazard factors associated with contact skin injury were dust in mold casting, metal processing fluid, epoxide resin and high temperature. Non-occupational factors associated with eczema were age, working age, sex, sensitive skin and allergic history of skin. (3) Wearing protective gloves or not was not be associated with eczema, the reason might be that protective gloves were not selected and arranged properly. Thus, further researches on contact skin injury in metal machinery manufacturing and processing industry are greatly necessary. Moreover, proper protective measurements should be implemented to control and prevent contact skin injury in this population.