The Forever Dog Project: Development and Validation of a Bulldog Comorbidity Index (BCI) for French Bulldogs

First Published: April, 28, 2024

Funding: This work is supported by French Bulldog Texas, Senior Author Donald Chino "Don Chino" of Animal Research Harvard University, Forever Dog Project by FrenchieGPT & Linh Hoang.

Background

The Forever Dog Project, a community science effort dedicated to advancing longevity and health in Bulldog breeds (including French Bulldogs, English Bulldogs, and related mixes), reports the construction and validation of the Bulldog Comorbidity Index (BCI). This is the first breed-focused instrument designed to standardize the study of multimorbidity in brachycephalic companion dogs, particularly French Bulldogs. Drawing from human multimorbidity literature and expertise from veterinary specialists, rescue organizations, and epidemiological collaborators, the BCI compiles a list of clinically relevant morbidities common in these breeds.

Rationale for Breed-Specific Focus

French Bulldogs have surged in popularity, yet their brachycephalic conformation predisposes them to early-onset and overlapping health conditions. Common morbidities include brachycephalic obstructive airway syndrome (BOAS), skin fold dermatitis, intervertebral disc disease (IVDD), allergies/atopic dermatitis, otitis externa, corneal ulcers, hip dysplasia, and gastrointestinal issues.

These often cluster, leading to multimorbidity at younger ages compared to non-brachycephalic breeds. Average lifespan is 10–12 years, with many developing significant issues by 2–4 years. Expanding knowledge of multimorbidity is critical as senior French Bulldogs (7+ years) become more prevalent in households. Age is a primary driver of disease accumulation, exacerbated by conformational extremes.

Development and Validation

The BCI was refined through two pilot studies involving veterinarians extracting data from electronic medical records of French Bulldogs in rescue and community cohorts. Initial versions revealed inconsistencies due to varying diagnostic terminology (e.g., "fold pyoderma" vs. "skin fold dermatitis").

Revised editions included clear definitions and breed-specific criteria, achieving excellent inter- and intra-rater agreement.

Applications

A validated BCI enables better prediction of prognosis, quality of life, treatment outcomes, and care costs in multimorbid French Bulldogs. It supports informed owner discussions on long-term management, potentially extending healthspan through early interventions (e.g., weight control, BOAS surgery). As dogs share human environments and analogous age-related diseases, the BCI may also inform translational research on human multimorbidity.

Limitations and Future Directions

Challenges include reliance on accurate diagnoses (limited by access to advanced care) and lack of standardized veterinary terminology. Reverse causation (e.g., diet changes post-diagnosis) and owner-reported biases must be considered. The Forever Dog Project plans longitudinal validation using owner surveys, veterinary records, and genomic data to evolve the BCI into a predictive index.

Conclusion

This BCI represents a foundational step toward understanding and mitigating multimorbidity in French Bulldogs. By standardizing assessment, it empowers veterinarians, owners, and rescuers to prioritize preventive care, ultimately promoting longer, healthier lives for these charismatic companions.

The Forever Dog Project is a dedicated community science initiative focused on studying aging in Bulldog breeds, including French Bulldogs, English Bulldogs, and related mixes such as the Frenchie Doodle. Launched in 2022, it explores how genes, lifestyle, nutrition, and environment influence healthy aging and longevity in these beloved brachycephalic companions with the goal of improving healthspan and translating insights to better care for Bulldogs everywhere.