“…Adjusted rate ratios (RRs) of injuries for hearing loss were calculated using a multivariate Poisson regression model while controlling for potential confounding factors. Age, farm working hours, off-farm work, noise exposure, farming acreages, raising livestock, dust and gas exposure, and smoking were adjusted as potential confounding factors because they were risk factors for work-related injuries in previous studies [Charante and Mulder, 1990;Barreto et al, 1997;Browning et al, 1998;Crawford et al, 1998;Leistikow et al, 1998;Hwang et al, 2001;Park et al, 2001;Carruth et al, 2002;Hager, 2002;Hard et al, 2002;Sprince et al, 2002;Sprince et al, 2003a,b;McCurdy et al, 2004;Rautiainen et al, 2004] and they were also related to hearing [Kleinbaum et al, 1982]. Each of the hearing variables was assessed separately in the model.…”