Changes in Circulating Levels of 25-hydroxyvitamin D3 in Breast Cancer Patients Receiving Chemotherapy

摘要

Cancer treatments, toxicities and their effects on lifestyle, may impact levels of vitamin D. The aim of this study was to determine serum 25-hydroxyvitamin D3 (25(OH)D3) levels before, directly after and 6 months after chemotherapy in breast cancer patients (n?=?95), and a comparison group of women (n?=?52) not diagnosed with cancer. Changes in 25(OH)D3 levels over time were compared using linear mixed models adjusted for age and season of blood sampling. Before start of chemotherapy, 25(OH)D3 levels were lower in patients (estimated marginal mean 55.8?nmol/L, 95% confidence interval (95%CI) 51.2–60.4) compared to the comparison group (67.2?nmol/L, 95%CI 61.1–73.3, P?=?0.003). Directly after chemotherapy, 25(OH)D3 levels were slightly decreased (–5.1?nmol/L, 95%CI –10.7–0.5, P?=?0.082), but ended up higher 6 months after chemotherapy (10.9?nmol/L, 95%CI 5.5–16.4, P?