Background: Acute occupational hand injuries are a common occurrence in China's metal manufacturing industries. This study aimed to explore the transient risk factors for acute occupational hand injuries among metal manufacturing workers. Methods: A case-crossover study was conducted from October 2013 through December 2013 in Zhongshan city, southern China. Face-to-face interviews were used to collect information on the occurrence of 12 transient risk factors during the “hazard” period (a 60-min period prior to occupational hand injury) and a “control” period (the week before the injury). Results: One hundred ninety-four qualified acute occupational hand injury cases (139 male, 55 female) were enrolled in this study, with a mean age of 35.5 (standard deviation [SD] 10.4) years. The most common (64.9%) type of work was punching, and the most common injures were crushes and fractures (28.8 and 23.7%, respectively). Of these cases, 62.9% were regarded as severe or major. Among the 12 transient risk factors, 11 ones were significantly associated with acute occupational hand injuries occurring during the hazard period: “replacing sharp knives” (IRR = 14.38, 95%CI 11.43–18.08), “using malfunctioning machinery” (IRR = 30.59, 95%CI 17.84–52.48), “using different tools” (IRR = 10.96, 95%CI 4.77–25.17), “using different machines” (IRR = 5.20, 95%CI 2.25–12.00), “performing unusual work tasks” (IRR = 24.38, 95%CI 14.11–42.15), “working overtime” (IRR = 13.40, 95%CI 7.70–23.29), “performing a task with a different method” (IRR = 56.41, 95%CI 23.61–134.81), “being in a bad mood” (IRR = 108.11, 95%CI 55.10–211.11), “feeling ill” (RR = 12.27, 95%CI 4.95–30.43), “rushing” (IRR = 5.16, 95%CI 2.49–10.70), and “not wearing gloves” (IRR = 1.63, 95%CI 1.23–2.15). Conclusions: Our study suggested that multiple transient risk factors were responsible for the acute occupational hand injuries in China's metal manufacturing industries. Am. J. Ind. Med. 59:832–840, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

metal manufacturing transient risk factors occupational hand injuries case-crossover Relative risk

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