A recent study published by the Journal of Feline Medicine and Surgery suggests that vitamin D status is related to white blood cell (WBC) count in hospitalized cats.
Neutrophils are a type of WBC that is released by the body to fight off infection. When an individual becomes injured or sick, neutrophils act as the body’s first responders and engulf pathogens present in the body. Due to their rapid response, a high neutrophil count may be an indicator of inflammation or illness in the clinical setting.
Past research has shown that vitamin D plays a crucial role in the immune system. In fact, most WBCs express vitamin D receptors, allowing vitamin D to regulate the innate and adaptive immune responses. However, despite the mounting evidence supporting the role of vitamin D in illness and inflammation in both humans and dogs, no research has been conducted investigating this relationship in cats.
Therefore, in the current study, researchers hypothesized that vitamin D status is negatively associated with WBC count in hospitalized cats. A total of 170 cats examined at the Hospital for Small Animals, Royal (Dick) School of Veterinary Studies, were included in the study. The researchers documented basic physical characteristics of the cats and measured their vitamin D levels and WBC count.
Here is what the researchers found:
- Cats with elevated neutrophil levels had lower serum 25(OH)D levels than those with neutrophils within the normal reference range. (P = 0.04).
- For every 10 ng/ml (25 nmol/l) increase in serum 25(OH)D, the odds of having normal neutrophil levels increased by 32%.
- Of the 12 cats with band (immature) neutrophils present, the median 25(OH)D status was 23.9 ng/ml, compared to the 39 ng/ml (59.8 nmol/l vs. 97.4 nmol/l) in cats with no band neutrophils.
The researchers summarized their findings,
“This study has demonstrated that cats with neutrophilia have lower vitamin D status than cats with a neutrophil count below the upper limit of the reference interval.”
Although successfully confirming their hypothesis, the researchers pointed out the main limitations to their study. Since neutrophil levels may increase due to stressful stimuli, it is unclear whether neutrophilia occurred as a result of hospitalization or inflammation in the body. Also, due to the cross sectional design, the researchers can’t determine if low vitamin D status is a predictor or result of elevated neutrophil levels.
Therefore they concluded,
“This study demonstrates the need to further clarify the relationship between inflammation and vitamin D status in cats.”
Sturges, M. & Cannell, JJ. Low vitamin D status linked to elevated white blood cell count in hospitalized cats. The Vitamin D Council Blog & Newsletter, February, 2016.