Kass, Philip H.
Kass, Philip H.
Kass, Philip H.
Now showing 1 - 4 of 4
- PublicationRisk factors for dog bites occurring during and outside of play: Are they different?(Elsevier, 2012-11-01)
; ; ;The aim of this study was to determine whether the effects of selected human-canine interaction/ environmental factors on bites occurring when the victim was and was not playing with the dog differed from each other. A veterinary clinic-based retrospective cohort study was conducted in Kingston, Jamaica (709), and San Francisco, USA (513) to compare the effects of selected exposures on non-play bites (161) relative to bites preceded by play with the dog (110) as reported by veterinary clients. Additionally, 951 non-biting dogs were used for a risk factor analysis of bites occurring during play. Using directed acyclic graphs and the change-in-estimate procedure to select and adjust for confounders, modified Poisson regression was used to estimate (a) the ratios of proportions of non-play bites out of all bites comparing exposed to unexposed dogs (proportionate bite ratios) and (b) risk ratios for bites occurring during play for each factor of interest. Proportionate bite ratios ranged from 0.84 to 1.29, with most 95% confidence intervals including one, thus implying a lack of specificity of effects of the examined factors on non-play bites relative to bites occurring during play with the dog. Consistent with this lack of specificity, risk ratios for bites occurring during play were similar in magnitude and direction to risk ratios previously published for non-play bites using the same non-biting dogs as a reference group. No country-specific differences in proportionate bite ratios were detected. Each human-canine environmental factor showed similar levels of association with both types of bites. One possible explanation is that both types of bites have a common causal pathway leading from each factor up to the point of human-canine contact. If the human-canine contact then leads to either play or non-play interactions with dogs and subsequently to both types of bites, the presence of such a common pathway would make the factor non-specific to either type of bite. As some of the examined factors are associated with increased frequencies of both types of bites, this could explain high percentages of bites occurring during play with the dog as reported in various case series of dog bites. If so, dog bite prevention strategies targeting these factors will simultaneously reduce the incidence of both types of bites. 350Scopus© Citations 14
- PublicationFactors associated with bites to a child from a dog living in the same home: A bi-national comparison(Frontiers, 2018-05-04)
; ; ;We conducted a veterinary clinic-based retrospective cohort study aimed at identifying child-, dog-, and home-environment factors associated with dog bites to children aged 5-15 years old living in the same home as a dog in Kingston, Jamaica (236) and San Francisco, USA (61). Secondarily, we wished to compare these factors to risk factors for dog bites to the general public. Participant information was collected via interviewer-administered questionnaire using proxy respondents. Data were analyzed using log-binomial regression to estimate relative risks and associated 95% confidence intervals (CIs) for each exposure-dog bite relationship. Exploiting the correspondence between X% confidence intervals and X% Bayesian probability intervals obtained using a uniform prior distribution, for each exposure, we calculated probabilities of the true (population) RRs ≥ 1.25 or ≤0.8, for positive or negative associations, respectively. Boys and younger children were at higher risk for bites, than girls and older children, respectively. Dogs living in a home with no yard space were at an elevated risk (RR = 2.97; 95% CI: 1.06-8.33) of biting a child living in the same home, compared to dogs that had yard space. Dogs routinely allowed inside for some portion of the day (RR = 3.00; 95% CI: 0.94-9.62) and dogs routinely allowed to sleep in a family member's bedroom (RR = 2.82; 95% CI: 1.17-6.81) were also more likely to bite a child living in the home than those that were not. In San Francisco, but less so in Kingston, bites were inversely associated with the number of children in the home. While in Kingston, but not in San Francisco, smaller breeds and dogs obtained for companionship were at higher risk for biting than larger breeds and dogs obtained for protection, respectively. Overall, for most exposures, the observed associations were consistent with population RRs of practical importance (i.e., RRs = 1.25 or =0.8). Finally, we found substantial consistency between risk factors for bites to children and previously reported risk factors for general bites. 277Scopus© Citations 13
- PublicationAge-related changes in the propensity of dogs to bite(Elsevier, 2013-08)
; ; ;This retrospective cohort study was aimed at describing the effects of age at acquisition, age, and duration of ownership of dogs on the risk of (1) bites during play and (2) non-play bites to humans. Data were collected on 110 dogs that had bitten during play with a person, 161 dogs that had bitten outside of play and 951 non-biting dogs from veterinary clients in Kingston (KGN), Jamaica and San Francisco (SF), USA. Modified Poisson regression was employed to model the relationships of both types of bites to each variable separately. Effects of the variables on dog bite risk (1) during and (2) outside of play with the dog, differed from each other and by type of bite. Effects varied with the dog's age and age-related associations were strongest in dogs younger than 1 year old. Ages at acquisition of dogs at highest risk for bites during play were substantially lower than those at risk for non-play bites. Ages and durations of ownership of dogs at highest risk for bites during play were also lower than those of dogs at highest risk for non-play bites. The propensity of a dog to bite changes as it ages and relationships between dog bites occurring during and outside of play and the dog's age at acquisition, current age, and duration of ownership, differ from each other. 210Scopus© Citations 5
- PublicationThe human–canine environment: A risk factor for non-play bites?(Elsevier, 2008-08)
; ; ;Few dog bite risk factor studies have been conducted. This veterinary clinic-based retrospective cohort study was aimed at identifying human-canine environmental risk factors for non-play bites in Kingston, Jamaica (660) and San Francisco (SF), USA (452). Data were analysed using modified Poisson regression with confounders selected using directed acyclic graphs (DAGs) and the change-in-estimate procedure. Dogs acquired for companionship were more likely (RR = 1.66; 95% CI 1.02-2.70) to bite than those acquired for protection. Routinely allowing a dog into the presence of visitors was also positively associated with it biting. A dog sleeping in a family member's bedroom was a risk factor for biting in Kingston (RR = 2.54; 95% CI 1.43-4.54) but not in SF, while being able to leave the yard unaccompanied was a risk factor for biting in SF (RR = 3.40; 95% CI 1.98-5.85) but not in Kingston. Overall, dogs which were less restricted in their interactions with humans were at elevated risk for biting. An observed association with dog bites in one cultural setting might not exist in another. 629Scopus© Citations 34