Vitamin A intake and elevated serum retinol levels in children and young adults with cystic fibrosis.

BACKGROUND: Individuals with cystic fibrosis (CF) and pancreatic insufficiency (PI) are at risk for fat-soluble vitamin deficiency, including vitamin A. Recent evidence suggests current practices of vitamin A intake results in elevated serum retinol.
METHODS: Serum retinol was assessed in 78 subjects (8 to 25 years old) with CF and PI by high performance liquid chromatography, and compared to the U.S. National Health and Nutrition Examination Survey (NHANES) data of subjects of similar age and gender. Vitamin A intake, anthropometry and FEV(1) were measured, and their relationship to serum retinol status was assessed.
RESULTS: Median (range) serum retinol was 80 microg/dL (33 to 208) in subjects with CF; 58% were above the NHANES reference range (30 to 72 microg/dL). Total vitamin A intake from diet and supplements was high (608+431% Recommended Dietary Allowance). Serum retinol was not correlated with vitamin A intake, age or gender, and was inversely correlated with weight and height z scores (r=-0.28, p<0.05) in the subjects with CF.
CONCLUSIONS: Both vitamin A intake and serum retinol were elevated in subjects with CF and PI, corroborating recent evidence of elevated serum retinol in preadolescent children with CF. These findings indicate the need for further study of dosing and monitoring care practices of vitamin A, to ensure adequacy and to avoid toxicity.