Behavioral changes in domestic dogs associated with exposure to secondhand smoke: A cross-sectional study

The close relationship between humans and domestic dogs underscores the importance of understanding factors influencing canine behavior, as unwelcome behaviors in pet dogs may have serious effects on the animals' and their owners' quality of life. Environmental factors, such as secondhand smoke, may significantly influence dogs’ behavior. However, this area remains underexplored. Although the association between passive smoking and behavioral changes in humans is well-documented, there is a paucity of research exploring similar effects in canines. This study examined 304 domestic dogs belonging to both smoker and non-smoker owners to assess the potential behavioral changes associated with secondhand smoke exposure. Detailed information, including sex, age, neutering status, and other relevant factors, was meticulously recorded for each dog. Owners completed a tailored questionnaire evaluating their dogs’ exposure to cigarette smoke. Behavioral traits were assessed using a validated Persian translation of the Dog Personality Questionnaire (DPQ). Statistical analysis revealed significant associations between secondhand smoke exposure and alterations in six key behavioral traits. Specifically, dogs exposed to cigarette smoke demonstrated increased fearfulness (OR=1.73), reduced activity levels (OR=1.77), heightened aggression towards people (OR=1.68) and other animals (OR=3.40), diminished trainability (OR=3.42), and elevated anxiety (OR=7.25). These findings suggest that dogs exposed to environmental cigarette smoke are at a higher risk for behavioral problems compared to those not exposed.