High Serum Retinol and Lung Function in Young Patients With Cystic Fibrosis

Abstract

The aim of the present study was to explore the relation between lung function and serum retinol (SR) in cystic fibrosis (CF) patients. This was a cross-sectional study conducted in a group of 98 young patients with CF (6.8-22.3 years), after the exclusion of those with pulmonary exacerbation, vitamin A deficiency, or other risks, from an initial group of 124 cases. Data of forced expiratory volume in 1 second (FEV₁) were widely scattered (87.7% ± 16.9%). These were similar in the 78 pancreatic insufficient and 11 pancreatic sufficient patients. SR (56.6 ± 18.4 μg/dL) was >2.5th percentile of healthy people in the whole group, although 31 patients were situated above the 97.5th percentile (higher value: 110 μg/dL). The FEV₁ was noticeably higher in these than in those within the normal range (93.6 ± 14.0 vs 85.0 ± 17.6 μg/dL; P < 0.05). The z score of SR correlated positively with FEV₁ (r = 0.364; P = 0.000), after adjusting data for sex, age, body mass index, and pancreatic function. The odds ratio for a FEV₁ >80% is 3.78 in patients with SR above the 97.5th percentile, versus only 0.26 in those within the normal range. There were no cases with retinol toxicity. FEV₁ of young patients with CF correlates positively with SR, regardless of age, pancreatic function, or nutritional condition. Those with a moderately high retinol (up to 110 μg/dL) maintain the best respiratory function (FEV₁ ≥80% in >90% of them) without any signs of toxicity.