Assessment of vitamin D status in common variable immunodeficiency or ataxia–telangiectasia patients

Abstract Introduction and objectives Vitamin D plays a role in the immune system, however studies regarding this are scarce. This study aimed to evaluate the nutritional status of vitamin D in patients with Common Variable Immunodeficiency (CVID) or Ataxia–Telangiectasia (A–T) and to relate it to body composition, inflammatory and bone metabolism markers. Patients and methods This is a cross-sectional and controlled study involving 24 patients of both sexes (59.3% male), aged 8–56 years, with CVID (n = 15) or A–T (n = 9). The following variables were evaluated: body mass index (BMI), 25-hydroxyvitamin D (25 (OH) D), hepatic profile, parathormone, calcium, phosphorus, alkaline phosphatase, interleukin 6 and high-sensitivity C-reactive protein. Results The median age was 26.0 years. A deficiency of 25 (OH) D was found in four A–T patients (44%) and two CVID patients (13%). Nine patients with CVI (60%) and six with A–T (66.7%) were overweight and underweight, respectively. There was a negative correlation between vitamin D and fat mass in the CVID group, and vitamin D and BMI in the A–T group. Vitamin D was negatively associated with the percentage of total fat among the patients (β – 0.842, 95% CI: −1.5–0.17, p = 0.015), R2 = 0.21, after adjusting for sex and age. Conclusion Vitamin D deficiency occurred in a quarter of the patients although there was no difference between the patient and the control group; without association with bone and inflammation biomarkers. The percentage of fat and BMI were negatively associated with the concentrations of 25 (OH) D.