Objective:

The aim of the present study was to explore the relation between lung function and serum retinol (SR) in cystic fibrosis (CF) patients.

Methods:

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.

Results:

Data of forced expiratory volume in 1 second (FEV 1) 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> 2.5 th percentile of healthy people in the whole group, although 31 patients were situated above the 97.5 th percentile (higher value: 110 μg/dL). The FEV 1 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 FEV 1 (r= 0.364; P= 0.000), after adjusting data for sex, age, body mass index, and pancreatic function. The odds ratio for a FEV 1> 80% is 3.78 in patients with SR above the 97.5 th percentile, versus only 0.26 in those within the normal range. There were no cases with retinol toxicity.

Conclusions:

FEV 1 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 (FEV 1≥ 80% in> 90% of them) without any signs of toxicity.