Which dogs bite? A case-control study of risk factors

Abstract

Objective: Dog bites cause an estimated 585,000 injuries resulting in the need for medical attention yearly and children are the most frequent victims. This study sought to determine dog-specific factors independently associated with a dog biting a nonhousehold member.

Methods: A matched case-control design comprising 178 pairs of dogs was used. Cases were selected from dogs reported to Denver Animal Control in 1991 for a first-bite episode of a nonhousehold member in which the victim received medical treatment. Controls were neighborhood-matched dogs with no history of biting a nonhousehold member, selected by modified random-digit dialing based on the first five digits of the case dog owner's phone number. Case and control dog owners were interviewed by telephone.

Results: Children aged 12 years and younger were the victims in 51% of cases. Compared with controls, biting dogs were more likely to be German Shepherd (adjusted odds ratio (ORa) = 16.4, 95% confidence interval (CI) 3.8 to 71.4) or Chow Chow (ORa = 4.0, 95% CI 1.2 to 13.7) predominant breeds, male (ORa = 6.2, 95% CI 2.5 to 15.1), unneutered (ORa = 2.6, 95% CI 1.1 to 6.3), residing in a house with > or = 1 children (ORa = 3.5, 95% CI 1.6 to 7.5), and chained while in the yard (ORa = 2.8, 95% CI 1.0 to 8.1).

Conclusions: Pediatricians should advise parents that failure to neuter a dog and selection of male dogs and certain breeds such as German Shepherd and Chow Chow may increase the risk of their dog biting a nonhousehold member, who often may be a child. The potential preventability of this frequent public health problem deserves further attention.