A Clinician’s guide to vitamin D supplementation for patients with cystic fibrosis

•Vitamin D deficiency is multifactorial in the cystic fibrosis population.•Vitamin D deficiency can adversely affect multiple organ systems in the cystic fibrosis population.•In the cystic fibrosis population in the United States, we aim to treat to serum 25-hydroxyvitamin D levels over 30 ng/ml.•Cholecalciferol is used in preference to ergocalciferol.•Daily or once weekly dosing regimens are chosen according to patient preference and compliance.