Survey says: Investigating environmental factors associated with a rare canine disease

A recent study led by CVM researchers investigated primary hypoadrenocorticism, also known as Addison’s disease, a disorder where part of the adrenal gland is destroyed, leaving it unable to produce certain hormones that are crucial for the body’s healthy functioning. It’s a complex disease, involving both genetic and non-genetic factors—but little is known about how environmental factors impact the development and trajectory of the disease. The study aimed to identify environmental risk factors associated with this disease to improve clinical management and explore potential therapeutic targets.

While generally rare, Addison’s affects up to 8–10% of specific breeds such as standard poodles and Portuguese water dogs, causing symptoms including gastroenteritis, poor appetite, slow loss of body condition, an inability to respond appropriately to stress, and potentially, death. There is no cure for the disease, and quality of life depends on lifelong treatment with medications.

The researchers conducted an online survey among owners of standard poodles and Portuguese water dogs with and without Addison’s in the United States and Canada, gathering data on the dogs' demographics, health history, and various environmental factors. Important findings from the study reveal a strong link between spaying or neutering dogs and the development of hypoadrenocorticism, a connection that has been previously noted in other research. This connection was particularly noticeable in neutered male dogs. While the study also found links with other factors like the type of community a dog lives in, their diet, and exposure to lawn fertilizers, these links were not as strong. 

The research suggests that the levels of sex hormones may affect a dog's overall risk and susceptibility to environmental factors related to hypoadrenocorticism.  Further studies are needed to confirm the findings, delve into the biological reasons behind them, and determine whether spaying or neutering might actually contribute to the development of the disease.

Researcher Amy Treeful says that next steps will do just this, using cell-based model systems such as adrenal organoids, which are “like miniature artificial organs, made of different groups of cells that are important for that organ,” and that mimic its structure and function.” In this case, they’ll use the models to “investigate whether the association between spay and neuter and primary hypoadrenocorticism can be explained through biological mechanisms.”

Read the full study in the Journal of Veterinary Internal Medicine.