Which Dogs Bite? A Case-Control Study of Risk Factors
In 1994, researchers released a study of "which dogs bite" based on 1991 Denver County dog bite data. The study mainly excludes pit bulls. In 1989, the city and county of Denver banned pit bulls.
- A matched case-control design comprising 178 pairs of dogs (about 18% of all reported dog bites in the testing area) was used. Cases were selected from dogs reported to Denver Animal Control in 1991 for a first-bite episode of a nonhousehold member where 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.
- Of the 991 dog bites reported to Denver Animal Control, only 178 cases were eligible (50% of those identified as potentially eligible and only 18% of all reported dog bites during the period).
- The median age of the bite victims was 12 years (range, 1 to 83 years); 64.7% of bite victims were males. Of the 83 bite victims, ages 12-year and younger, 33 (40%) were bitten on the face, head or neck. Though not standardized, bite severity was indicated on bite reports for 135 (75.8%) incidents. 103 (76.3%) of these were minor bites and 32 (23.7%) were recorded as severe.
- Bite report forms indicated where the bite episode occurred for 101 (56.7%) of the incidents. Of these, 51 (50.5%) took place on the sidewalk, street, alley or playground; 30 (29.7%) in the owner's yard; 14 (13.9%) in the owner's house; and 4 (4.0%) in the victim's yard.
- Dogs predominantly of chihuahua, golden retriever, labrador retriever, poodle, Scottish terrier, and Shetland sheepdog breeds were more common among nonbiting than among the biting dogs. None of the cases and only one control dog was a pit bull terrier (new ownership of pit bull terriers has been prohibited in Denver county since 1989).
- Dogs predominantly of German shepherd, chow chow, collie and akita breeds were substantially more frequent among biting than nonbiting dogs. The total numbers of dogs predominantly of collie (n=9) and akita (n=5) breeds were small compared to the total numbers of German shepherd (n=47) and chow chows (n=40) predominant breed dogs.
- Biting dogs were significantly more likely than control dogs to be German shepherd or chow chow predominant breeds, to be male, to reside in a house with one or more children, and to not be neutered. Biting dogs were also more likely to be chained while in the yard; this association reached borderline significance.