Healthiest US Region for Dogs?

Hello Summarians!

What role does the environment play in our overall health? A great question that is frustratingly difficult to tease out. There are numerous variables, and typically, the ability to track large populations is challenging to find in non-human animal population studies.

Thankfully, we have the Dog Aging Project (DAP). This study also appears in our research on dog aggression.

If you learned something new, please share it with a friend.

Lidocaine for GI Surgery

Gastrointestinal foreign bodies are a frequent surgical emergency in veterinary practice and can lead to compromised blood flow, intestinal necrosis, ileus, and significant discomfort. Although full μ opioid agonists like hydromorphone and fentanyl are commonly used for postoperative analgesia, they may delay gastrointestinal motility and prolong ileus, contributing to nausea and vomiting. Lidocaine, known for its analgesic, anti-inflammatory, and prokinetic effects, has been shown in humans and some animal studies to reduce pain, opioid requirements, and postoperative ileus. 

This study evaluated whether continuing intraoperative lidocaine infusions postoperatively for 24 hours at 1.8 mg/kg/h would improve outcomes in dogs undergoing exploratory laparotomies for GI obstruction. The objectives were to determine whether lidocaine would reduce pain and nausea scores, shorten hospitalization, decrease vomiting and diarrhea, and reduce opioid needs, while also describing lidocaine pharmacokinetics and metabolite profiles. 

The study found no significant differences between the lidocaine and placebo groups regarding pain scores, nausea, incidences of vomiting and diarrhea, or hospitalization duration. These results contrast with prior studies showing benefits from lidocaine infusions. It is possible that adequate analgesia from premedication, induction drugs, and intraoperative lidocaine minimized the need for further analgesia postoperatively. Additionally, the CMPS-SF pain scoring tool, while validated for acute soft-tissue pain, may not have been fully appropriate for GI surgery, and observer variability may have influenced results. 

Pharmacokinetic analysis confirmed plasma lidocaine and metabolite levels within or above therapeutic ranges without evidence of accumulation or toxicity, although lidocaine metabolites’ role in analgesia in dogs remains poorly characterized. Interestingly, a higher incidence of rescue analgesia was observed in the lidocaine group, potentially due to falsely elevated pain scores during early recovery when residual anesthetic effects are known to confound pain assessment. Other speculative explanations include lidocaine-related behavioral effects, though no clear evidence of hyperalgesia or toxicity was found. 

Clearance estimates for lidocaine were consistent with previous data, and no substantial accumulation occurred apart from one outlier. Limitations included missing data points due to sedation, catheter issues, and logistical interruptions; the use of only one lidocaine dose; and occasional additional procedures or sedative administration, which may have influenced outcomes. 

Overall, the study concluded that postoperative lidocaine infusions at the tested dose did not significantly improve clinical outcomes in dogs after GI foreign body removal surgery. Given that these patients generally experienced minimal postoperative discomfort, routine pain and nausea assessments and careful opioid use remain important components of optimal postoperative care. 

Burns, C. C., Barletta, M., Junis, Z., Moore, G., Messenger, K., Dantino, S., Reed, R. A., Knych, H., & Quandt, J. (2025). Pharmacokinetics and effect of postoperative lidocaine infusions on pain and nausea scores in canine patients undergoing gastrointestinal foreign body surgery. American Journal of Veterinary Research https://doi.org/10.2460/ajvr.25.02.0054 

Bottom line — No, it did not work.

Environmental Influences and Health.

Epidemiologists have long investigated how the environment contributes to disease in humans and animals. To better understand these complex relationships, large-scale population-based studies are essential. In the United States, companion dogs offer an accessible way to capture this data due to their shared environments with people and the wide geographic, climate, and cultural diversity they experience. The Dog Aging Project (DAP) is a longitudinal study designed to collect detailed environmental and health data on dogs to inform translational research relevant to both canine and human health. 

This study assessed which environmental and lifestyle variables in the DAP dataset differed by U.S. region and explored associated health condition patterns. Prior research has already demonstrated that environmental exposures such as secondhand tobacco smoke, herbicides, and insecticides are linked to cancer risk in dogs, and factors like breed, body size, and snout length can modify exposures and disease susceptibility. Rural and urban dogs differ in their likelihood of encountering antibiotic-resistant bacteria, for example, due to differences in diet and outdoor activity. Ambient pollutants and social determinants of health also vary widely across regions. However, no previous dataset has comprehensively mapped these exposures and outcomes across the entire U.S. dog population. 

This analysis found regional differences in exposures both within homes and in the surrounding environments. Factors like water pipe materials, presence of asbestos or lead, and heating or cooling systems appeared related to the age of homes. Weather differences between regions were as expected, but dog activity levels did not vary, suggesting that owners adapt their pets’ routines regardless of season. Radon exposures were reported most frequently in the Northeast and Midwest, consistent with Environmental Protection Agency maps, though lower reporting in the West may reflect either regional sampling biases or greater radon mitigation. 

Outdoor exposures also varied by region. Dogs in the West were more likely to encounter sand and artificial grass, while swimming exposures differed by the availability of oceans, lakes, and pools. The South reported the most yard pest and weed treatments, raising concerns about higher chemical exposures in dogs there. Health diagnoses also showed regional variation, including differences in oral, skin, infectious, toxin ingestion, and trauma categories. Some of these differences aligned with known disease patterns, such as tick-borne diseases in the Northeast, while others could not be attributed to specific conditions within categories. Built environment factors and differences in dog management practices may explain some of these patterns, although further research is needed. 

The study acknowledges limitations, including reliance on owner-reported data that may be biased or inaccurate and potential overrepresentation of certain demographics due to voluntary participation. Still, this high-level view of environmental exposures provides critical guidance for future research. Understanding regional differences in environmental exposures and health outcomes is key to improving veterinary disease prediction, prevention, and treatment. Additionally, because dogs often experience environmental exposures earlier or more intensely than humans, this research offers valuable insights into health risks shared across species. As the DAP cohort ages, continued follow-up will help reveal links between specific exposures and long-term disease development, potentially identifying threats to human health sooner than human studies alone could achieve. 

O'Brien, J. S., Grzywinski, M., Sexton, C. L., Dog Aging Project Consortium, Dunbar, M. D., & Ruple, A. (2025). Environmental exposures and health outcomes in dogs differ according to geographic region in the United States among Dog Aging Project participants. American Journal of Veterinary Research https://doi.org/10.2460/ajvr.25.04.0121 

Bottom line — Regional influences can be important.

Owner Reported Dog Aggression

Understanding dog behavior—particularly aggression—is critically important for veterinarians because aggression can result in serious injuries to humans and other animals. While the true annual incidence of dog bites in the U.S. remains uncertain, estimates suggest about 4.7 million people are bitten each year, with around 800,000 requiring medical attention, 330,000 treated in emergency departments, and 30–80 fatalities reported annually. These figures underscore the significance of canine aggression as a public health issue. Aggression is also a frequent reason owners seek professional help, relinquish dogs to shelters, or choose euthanasia. 

Studies examining canine aggression have identified numerous contributing factors, including the dog’s age, sex, neuter status, genetic background, and environmental influences. However, most data come from specialty practices managing severe cases rather than the general dog population. Reported prevalence rates vary widely, from about 10% in some general surveys to over 75% in studies of cases seen by behavior specialists. A recent survey found that aggression was the second most common behavior concern reported by 55.6% of owners. 

The Dog Aging Project (DAP) offers large-scale data collection that includes behavior assessments using a shortened version of the validated Canine Behavioral Assessment and Research Questionnaire (C-BARQ). This version includes 10 aggression-related questions where owners rated their dogs from 0 (no aggression) to 4 (serious aggression). According to DAP data, separation-related behaviors were most prevalent, with 85.9% of dogs rated moderately to seriously affected. Aggression followed, with over half of dogs reported to show at least some agonistic behavior. In fact, the number of moderate to severe aggression ratings across all questions exceeded the number of dogs, indicating that many dogs displayed such behaviors in multiple contexts. 

These findings highlight a potential underrecognition of lower-level aggression. Owners often dismiss growling or snapping as unimportant, even though these behaviors can precede more serious incidents. Data indicate that people relinquishing dogs often underreport aggression severity, particularly when questionnaires are not confidential, which can jeopardize future adopters. Even veterinary students can miss subtle early signs without targeted training in canine body language. 

Survey-based studies have limitations. Respondents may misunderstand what constitutes aggression, inconsistently interpret the timeframe for “recent” behavior, or misclassify fear-related responses as aggression. Despite these challenges, surveys provide valuable large-scale insights and help veterinarians anticipate which behaviors may warrant closer examination. 

In conclusion, while the DAP data likely reflect a motivated subset of dog owners, they represent a large, diverse sample. Most dogs in the study exhibited little or no agonistic behavior overall. Of the approximately 57% that did show any such behavior, many displayed it only occasionally or in limited contexts. Even so, the findings reinforce that canine aggression is both common enough and serious enough to merit sustained attention from veterinary professionals, particularly given the risks it poses to public safety and animal welfare. 

Bonnie V. Beaver, Owner reported prevalence and severity of canine aggression in the United States: A descriptive study, Journal of Veterinary Behavior, Volume 79, 2025, Pages 1-6, ISSN 1558-7878, https://doi.org/10.1016/j.jveb.2025.04.002. 

Bottom line — It is a common problem.

Just putting things in perspective …