Risk factors for animal-related injury among Iowa large-livestock farmers: a case-control study nested in the agricultural health study

Although farmers are at risk for injuries from contact with large livestock, few previous studies have examined risk factors for animal-related injuries. This case-control study, nested in the Agricultural Health Study, aimed to assess risk factors for animal-related injury among Iowa large-livestock farmers. A screener questionnaire sent to 6999 farmers identified 116 farmers with large livestock who had an animal-related injury requiring medical advice/treatment in the previous year. Several possible risk factors for injury were assessed by comparing these farmers with 342 farmers who had livestock but were not injured in the previous year. A multiple logistic regression analysis showed significant associations between animal-related injury and the use of a hearing aid (odds ratio [OR] = 5.4 [95% CI, 1.6 to 18.0]), doctor-diagnosed arthritis or rheumatism (OR = 3.0 [95% CI, 1.7 to 5.2]), education beyond high school (OR = 1.8 [95% CI, 1.1 to 2.8]), and a younger age. Farmers engaged in off-farm work were less likely to sustain animal-related injuries (OR = 0.4 [95% CI, 0.2 to 0.8]). This is the first study to show associations between animal-related injury and a younger age, hearing difficulties, and doctor-diagnosed arthritis. Hearing loss and arthritis, which are more common among farmers than among other workers, may be particularly important risk factors to address in future preventive studies.