Open AccessInfluence of Various Factors on Circulating 25(OH) Vitamin D Concentrations in Dogs with Cancer and Healthy Dogs
Author(s) -
Weidner N.,
Woods J.P.,
Conlon P.,
Meckling K.A.,
Atkinson J.L.,
Bayle J.,
Makowski A.J.,
Horst R.L.,
Verbrugghe A.
Publication year - 2017
Publication title -
journal of veterinary internal medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.356
H-Index - 103
eISSN - 1939-1676
pISSN - 0891-6640
DOI - 10.1111/jvim.14834
Subject(s) - medicine , vitamin d and neurology , endocrinology , parathyroid hormone , cancer , cyp24a1 , prostate cancer , hormone , calcitriol receptor , calcium
Background Low blood 25‐hydroxyvitamin D (25( OH )D) concentrations have been associated with cancer in dogs. Little research has examined what other factors may affect 25( OH )D concentrations. Objectives (1) To determine whether the presence of cancer (lymphoma, osteosarcoma, or mast cell tumor [ MCT ]) in dogs is associated with plasma 25( OH )D concentrations and (2) identify other factors related to plasma 25( OH )D concentrations in dogs. Animals Dogs newly diagnosed with osteosarcoma (n = 21), lymphoma (n = 27), and MCT (n = 21) presented to a tertiary referral oncology center, and healthy, client‐owned dogs (n = 23). Methods An observational study design was used. Dietary vitamin D intake, sex, age, body condition score ( BCS ), muscle condition score ( MCS ), and plasma concentrations of 25( OH )D, 24,25‐dihydroxyvitamin D (24,25( OH ) 2 D) (a marker of CYP 24A1 activity), as well as ionized calcium ( IC a), parathyroid hormone, and parathyroid hormone‐related protein concentrations were measured. An analysis of covariance was used to model plasma 25( OH )D concentrations. Results Cancer type ( P = 0.004), plasma 24,25( OH ) 2 D concentrations ( P < 0.001), and plasma IC a concentrations ( P = 0.047) had significant effects on plasma 25( OH )D concentrations. Effects of age, sex, body weight, BCS , MCS , and plasma PTH concentrations were not identified. A significant interaction between IC a and cancer was found ( P = 0.005). Plasma 25( OH )D concentrations increased as IC a concentrations increased in dogs with cancer, whereas plasma 25( OH )D concentrations decreased as IC a concentrations increased in healthy dogs. Conclusions and Clinical Importance Results support a relationship between cancer and altered vitamin D metabolism in dogs, mediated by plasma IC a concentrations. The CYP 24A1 activity and plasma IC a should be measured in studies examining plasma 25( OH )D concentrations in dogs.