Environmental exposures and health outcomes in dogs differ according to geographic region in the United States among Dog Aging Project participants.

Objective: To determine which environmental exposures, lifestyle variables, and prevalences of health conditions within the Dog Aging Project population differed by geographic region. Methods: For this cross-sectional descriptive study, owner-reported environmental and lifestyle factors from 47,444 individuals enrolled in the Dog Aging Project cohort from January 1, 2020, through December 31, 2023, were examined across census regions, and 95% CIs were computed for each individual factor across the regions. Results: Analyses indicated high variation in the characteristics of dogs' environments across the US regions, including both inside and outside of the home. Certain types of diseases disproportionately affect dogs in some regions: infectious diseases were most prevalent in the Northeast (49%; 95% CI, 48% to 50%), dental disease was highest in the West (46%; 95% CI, 45% to 47%), and skin conditions were most prevalent in the South (45%; 95% CI, 44% to 45%). Dog activity levels did not vary significantly across regions. Conclusions: There are regional differences in lifestyle and environmental exposures experienced by companion dogs across the US, such as pesticides and weed treatments applied to yards, swimming water sources, and home heat sources, whereas other exposures do not differ across regions. The prevalence of some health conditions, like infectious/parasitic diseases, dental disease, and skin conditions, varied by regions, whereas others, like cancer, neurologic, and gastrointestinal diseases, showed no regional variation. These findings inform future hypothesis-driven studies of environmental health risks of dogs, which are relevant to translational research. Clinical Relevance: There are regional variations in exposures that may contribute to differences in the prevalence of health conditions found in companion dog populations.