Which Dogs Bite? A Case-Control Study of Risk Factors (1991)

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Study highlights

• 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 that required medical treatment.
• 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, aged 12 and younger, 33 (40%) were bitten on the face, head or neck. When indicated on the bite report forms, 75.8% of all incidents, 32 (23.7%) of bites 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.
• 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 mainly 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).
• Biting dogs were significantly more likely to reside in homes with one or more children, ages 10 years and younger, and to be chained while in the yard. Of the 83 chained dogs, 44 (53%) had growled or snapped at visitors to the house. This same behavior, however, was reported in unchained dogs 44% of the time.