Vitamin D status in female dogs with mammary gland tumors

Abstract

Background: Little information exists about vitamin D status in bitches with mammary tumors.

Objectives: To determine whether low plasma vitamin D concentrations are found in bitches with mammary tumors.

Animals: Eighty-five client-owned bitches with mammary tumors (n = 21 benign, n = 64 malignant) and 39 age-matched healthy bitches.

Methods: Case-control study. Plasma ionized and total calcium, phosphorus, magnesium, urea, creatinine, albumin, total proteins, alanine aminotransferase, alkaline phosphatase, parathyroid hormone (PTH), calcitriol (1,25-dihydroxyvitamin D), and 25-hydroxyvitamin D concentrations were measured in all bitches at the time of clinical diagnosis and before any treatments. Statistical analysis was performed to compare variables among groups (control, benign, and malignant).

Results: No significant differences were found when plasma 25-hydroxyvitamin D concentrations in bitches with malignant (148.9 [59.9] ng/mL) and benign mammary tumors (150.1 [122.3] ng/mL) were compared with control group (129.9 [54.5] ng/mL). Parathyroid hormone was significantly higher in bitches with malignant (19.9 [20.5] pg/mL), and benign mammary tumors (14.6 [14.9] pg/mL) compared with control group (7.5 [7.5] pg/mL; P < .01). Only the presence of mammary tumors (P < .01) and age (P = .04; adjusted R² = .22) was significant in predicting PTH.

Conclusions: Bitches with mammary tumors do not have low 25-hydroxyvitamin D concentrations thus vitamin D supplementation is unlikely to be useful for prevention of mammary tumors in bitches.

Keywords: 1,25‐dihydroxyvitamin D; 25‐hydroxyvitamin D; canine; mammary cancer; mineral metabolism.

FIGURE 1

Plasma 25‐hydroxyvitamin D (A), 1,25‐dihydroxyvitamin D (B), and parathyroid hormone (C) concentrations in control bitches (n = 39) and bitches with mammary (benign [n = 21] and malignant [n = 64]) tumors. The boxes represent the 25th and 75th percentiles (quartile 1 and quartile 3, respectively) and the central lines in the boxes represent the median values. The circle corresponds to out‐of‐range values (defined as any value reaching past 1.5 times the interquartile range below the 1st quartile and above the 3rd quartile). *A significant difference (P < .05 after Bonferroni adjustment) compared to control group.