简介：AbstractImportance:Vitamin A (or retinol) has considerable antioxidative and anti-inflammatory attributes and it may have protective effects on the respiratory health of patients with cystic fibrosis (CF). This issue, however, remains controversial.Objective:The purpose of the present study was to investigate the relationship between serum retinol levels (SRL) and force expiratory volume in 1 second (FEV1) in patients with CF.Methods:All patients with pancreatic insufficiency attending the CF Department of "Agia Sofia" Children’s Hospital in Athens, Greece, aged 6 to 19 years during the 2012-2016 period, who could perform spirometry effectively, were included in the study. The impact of SRL on FEV1 was examined longitudinally and analyzed with generalized estimating equations.Results:The study included 231 patients and 851 SRL measurements were performed. In 25 (3.2%) cases the SRL were below the 5th percentile of reference distribution; none was above the 95th percentile. The analysis showed that SRL was positively correlated with the FEV1 (P < 0.001).Interpretation:In this sample of children and adolescents with CF, vitamin A deficiency was rare. Our results suggest a positive relationship between SRL and FEV1.