BERKELEY, CA (UroToday.com) - Serum vitamin D is not only a predictor of bone health but also an independent predictor of risk for cancer and other chronic diseases.
Our aim was to evaluate calcium intake and vitamin D levels in patients with prostate cancer, and to determine the relationship between dietary calcium intake (DCI), 25 OH vitamin D and bone mineral density (BMD).
Our cross-sectional study included 91 subjects with a diagnosis of prostate cancer in Granada, Spain (latitude 37.11 N). All were Caucasians, had normal values of serum calcium and phosphorus, and had neither renal, hepatic, gastrointestinal nor thyroid diseases nor other secondary causes for low BMD except secondary hypogonadism. None of them had been treated with calcium supplements, vitamin D preparations, antiresorptive therapy, thiazides, steroids, or other medications that might affect bone mass. After that, we considered two groups: group 1 (n = 42): patients who have never received hormonal therapy; group 2 (n = 49): patients receiving androgen deprivation therapy (ADT) with GnRH agonists (triptorelin, goserelin, leuprorelin) or anti-androgens (bicalutamide, flutamide). The mean duration of ADT was 27 months (range 3-96 months). Dietary calcium intake was estimated using a standard questionnaire. The Short Calcium Questionnaire (SCQ) is a Food Frequency Questionnaire (FFQ) developed from the Calcium Questionnaire, reflecting major dietary sources of calcium.
DCI was low in prostate cancer patients (394±201 mg) according to current recommendations. Only two patients (2.2%) had a DCI of 1000 mg/day. There was no difference in calcium intake according to ADT treatment (ADT 343±172 mg/day vs. no ADT 454±218 mg/day, p = 0.08). Medium vitamin D levels showed no differences in patients with or without ADT (ADT 20.92±12.1 ng/dl vs. no ADT 22.58±10.96 ng/dl, p = 0.51). There was no correlation between DCI, 25 OH vitamin D levels and BMD. Vitamin D deficiency and insufficiency were highly prevalent. In the entire cohort, only 22% (20 patients) of patients had adequate levels of vitamin D, whereas 29.7% (27) of patients were vitamin D deficient and 48.3% (44) were classified as vitamin D insufficiency.
Our data showed a higher percentage of patients with vitamin D deficiency and insufficiency than previous reports in prostate cancer patients. There have been proposed many factors contributing to low vitamin D levels: the infrequent use of vitamin D as a part of treatment, the use of inadequate doses as a result of the conservative level of vitamin D supplementation usually recommended, the limited availability of vitamin D in foods, and the use of sun screens and limited outside activity. The known consequences of vitamin D deficiency in prostate cancer, i.e. increased risk of medical complications, a possible effect in cancer progression and prognosis, and the importance of vitamin D in the development of osteoporosis confirms the relevancy of this condition.
Our results are in agreement with previous reports evaluating vitamin D levels in patients with prostate cancer that showed similar levels of vitamin D deficiency and insufficiency independently of stage of disease.
This study has some limitations. The cross-sectional design does not allow to determinate a relationship between serum vitamin D levels and the progression of disease. Strengths of the study are the inclusion of a well-characterized cohort of prostate cancer patients, the evaluation of DCI by a validate questionnaire, the determination of 25 OH vitamin D levels in all patients, and the evaluation of BMD in all patients by DXA.
In summary, in prostate cancer patients’ dietary calcium intake is low according to current recommendations and vitamin D deficiency is highly prevalent. Additional research is needed to establish the consequences of low calcium intake and vitamin D deficiency in prostate cancer patients. Dietary counseling and adequate treatment with calcium and vitamin D supplements could improve bone health in this group of patients.
Written by:
Mariela Varsavsky, Rebeca Reyes-García, María Cortés-Berdonces, Antonia García-Martin, Pedro Rozas-Moreno, and Manuel Muñoz-Torres as part of Beyond the Abstract on UroToday.com. This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.
Unidad de Metabolismo Óseo
Endocrinología
Hospital Universitario San Cecilio
Granada, Spain
Serum 25 OH vitamin D concentrations and calcium intake are low in patients with prostate cancer - Abstract
UroToday.com Prostate Cancer Section