Risk factors for human-directed aggression by dogs: The human side of the problem. A two-part systematic review and narrative synthesis

Abstract

Dog bites are a significant public health problem. This two-part systematic review examines the characteristics of dog owners and owner-to-dog interactions as risk factors for human-directed dog aggression. Part One considers characteristics specific to dog owners that may affect risk and Part Two the interactions an owner may have with their dog. Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines were followed, although significant differences in the characteristics of the populations, study aims and methodologies, and available data across studies precluded the use of meta-analytic techniques so a narrative synthesis was undertaken. In Part One, 21 articles satisfied all inclusion criteria, and 18 articles were included for review in Part Two. The quality of the research in respect of identifying risk factors for human-directed dog aggression was assessed using an adapted Critical Appraisal Skills Programme (CASP) checklist. In Part One our analysis indicates that there is at least reasonable scientific evidence to support dog owning experience, the owner’s age, socioeconomic status, and owner personality as risk factors for human-directed dog aggression. However, the important factors possibly underpinning these relationships need to be elucidated further, to determine causality. It has been suggested that an owner’s involvement in criminal activity or gang culture, and the owner being part of a single parent household may affect the risk of human-directed dog aggression, however, the evidence for this is weaker. In Part Two we identified robust evidence for a relationship between the use of physical punishment or confrontational training methods and increased human-directed dog aggression. The purpose for which a dog was acquired, interaction styles of the owner toward the dog and the amount of time spent engaged in exercise or social activities with the dog were also identified as risk factors, though the scientific evidence for these is less robust. Aspects of husbandry and management, for example feeding a dog from the table, are suggested in the literature to be risk factors for human-directed dog aggression, however, the evidence to support these is weak. The review identified recurring methodological limitations in the research, with assumptions made over the causal nature of relationships when a bidirectional relationship might plausibly exist. Suggestions are made for future research directions to increase our understanding of risk factors specific to dog owners and owner-to-dog interactions, enable effective intervention and education strategies to be developed and inform government policy to reduce the risk of dog bite incidents.