Relationships between plasma vitamin D concentration and total leukocyte count, neutrophil count, and hemoglobin concentration in dogs

Objective: This study aimed to determine plasma vitamin D concentration in dogs with various diseases characterized by abnormal total leukocyte count (TLC) and neutrophil count (NeuC) or anaemia, and to evaluate its relationships with TLC, NeuC, haemoglobin concentration (Hb), and haematocrit value (HCT). Material and Methods: A total of 59 dogs with various diseases, including those with alterations in total leukocyte count (TLC) and neutrophil count (NeuC) (n=26), anaemic and non-anaemic (n=33), and 21 healthy control dogs were examined. TLC, NeuC, Hb, and HCT by haematology analyser and plasma 25(OH) vitamin D concentration, the hallmark of vitamin D status, using a canine-specific ELISA kit were measured. The comparisons and relations between groups using parametric or nonparametric tests were performed. Results: Plasma 25(OH) vitamin D concentration was significantly lower in dogs with neutrophilic leucocytosis (median: 57.20 μg/L) and anaemic dogs (54.21 μg/L) than in healthy dogs (168.9 μg/L; both p<0.001). Plasma 25(OH) vitamin D concentration was negatively correlated with TLC (rho = 0.41) and NeuC (rho = 0.43) in 26 dogs with abnormal TLC and NeuC. There were significant positive correlations between plasma 25(OH) vitamin D concentration and both Hb (rho = 0.49) and HCT (rho = 0.49) in anaemic and non-anaemic group. Conclusion: Future studies are needed to assess whether a low plasma 25(OH) vitamin D concentration is a cause or consequence of diseases with abnormal TLC and NeuC or decreased Hb and HCT in dogs.