According to a new study published by the BMC Veterinary Research journal, low vitamin D status is associated with poor prognosis in dogs with protein losing enteropathy.
A dog’s health is largely reliant on its ability to properly utilize nutrients. When the body is unable to adequately digest or absorb nutrients from the diet, weight loss, poor coat condition and chronic disease states are likely to follow.
Canine protein losing enteropathy (PLE) is a condition affecting the gastrointestinal tract that results in protein loss through the intestines. During the normal digestion process, a small number of amino acids (the building blocks of proteins) may re-enter the intestines through the blood vessels. The intestine releases most of these amino acids back into the bloodstream to be utilized to produce more proteins. However, in cases of PLE, more proteins leak into the intestines than the body can replace.
Symptoms of PLE include diarrhea, weight loss, lethargy, muscle wasting, edema in the legs and a distended abdomen. Dogs with PLE commonly have elevated markers of inflammation and immunoreactivity. Severe cases of PLE may result in death.
Vitamin D plays an important role in maintaining a healthy inflammatory, immune response and regulates barrier function. Although research has found that low vitamin D status is associated with chronic enteropathies in dogs, the clinical implications of low vitamin D status remains unclear. Therefore, researchers recently conducted a study to determine whether low vitamin D status may affect the prognosis of PLE in dogs.
Forty-three dogs diagnosed with PLE were included in this retrospective study. The dogs were separated into two groups based off their treatment regimen: Group 1 received an elimination or hydrolyzed diet, while group 2 received the elimination or hydrolyzed diet along with immunosuppressive medication.
The researchers obtained the dogs serum vitamin D levels and ionized calcium (iCa) levels at the time of diagnosis. Low iCa levels are commonly seen in dogs with PLE. The researchers theorized that this may be due to intestinal vitamin D malabsorption. The outcome of PLE was provided to the researchers by the dogs’ veterinarians.
Here is what the researchers found:
- A total of 22 dogs died within 4 months of diagnosis of PLE, while 21 survived at least 1 year post diagnosis.
- Dogs treated with dietary adjustments alone without the use of immunosuppressive drugs were more likely to have a positive outcome (p < 0.001).
- Serum iCa levels were positively associated with 25(OH)D status (p < 0.0005).
- Vitamin D levels were significantly lower in dogs who passed away within 4 months of diagnosis, compared to those who survived at least 1 year after diagnosis of PLE (6.6 ng/ml vs. 14.8 ng/ml, respectively; p = 0.017).
- After adjusting for confounders, serum 25(OH)D status was the only statistically significant risk factor for PLE outcome (p = 0.0333)
- Every 2.5 ng/ml increase in 25(OH)D levels was associated with a decreased risk (HR: 0.974; 95% CI: 0.949, 0.999) of poor outcome.
The researchers concluded,
“This study shows for the first time that low 25(OH) D serum concentrations and low iCa serum concentrations are highly prevalent in a cohort of PLE dogs, and that decreased 25(OH)D serum concentrations are significantly associated with negative outcome.”
As always, it is important to recognize the study’s limitations. Due to its observational design, it is impossible to determine whether a causal relationship exists. Additionally, the dog’s 25(OH)D levels were measured via radioimmunoassay, a method which lacks the high specificity of liquid chromatography, mass spectrometry (LCMS), the gold standard in vitamin D testing.
There remains a lack of consensus among the research and veterinary communities regarding the proper dosage and reference ranges to promote optimal health among canines. With continued research suggesting low vitamin D status negatively impacts various chronic health conditions, it is crucial that the veterinary and research communities begin working together to determine the optimal dosage and vitamin D status in dogs
Sturges, M. & Cannell, JJ. Low vitamin D status associated with impaired outcome in dogs with protein losing enteropathy. The Vitamin D Council Blog & Newsletter, 4/2017.