Effects of Vitamin D Supplementation in Adolescents With Asthma, Obesity and Vitamin D Deficiency.

Randomized controlled, double-blind, parallel (2 arms), clinical trial. Eligibility criteria: adolescents (12-17 years old), with obesity, vitamin D deficiency (\<30 ng/dl), controlled or partially controlled or uncontrolled asthma according to GINA 2020 criteria and confirmed with a spirometry, with negative allergy skin test. To each patient it will be performed a medical history, physical examination, asthma control questionnaire, a spirometry (with bronchodilator), as well as a peripheral blood sample collection of 10 ml to measure Th17 inflammatory biomarkers by chemiluminescence immunoassay and quantitative polymerase chain reaction (genetic expression of 18 cytokines) and 25-hydroxyvitamin D plasmatic concentration with electrochemiluminescence. Patients will be randomized by block and assigned to one of two intervention arms. Each intervention arm will have a total sample of 132 patients. Experimental group will receive a single dose of 50,000 IU and 4,000 IU of vitamin D daily for 3 months. On the other hand, the active control group will receive 2,000 IU daily for 3 months. Patients will be followed up and cited every month for clinical assessment, asthma control (ACQ) questionnaire application, spirometry (with bronchodilator) and peripheral blood sample collection to determine the plasma concentration of 25-hydroxyvitamin D and Th17 inflammatory biomarkers.