Vitamin A levels in patients with CF are influenced by the inflammatory response

Abstract

Background: Serum vitamin A, normally depressed in inflammatory conditions, is frequently low in people with CF. Vitamin A is important in respiratory epithelial regeneration and repair. We hypothesised that serum vitamin A would be associated with inflammation and disease severity. Methods: Serum vitamin A (as retinol), C-reactive protein (CRP), vitamin E, 25-hydroxy vitamin D (25OHD), 1,25-dihydroxy vitamin D (1,25(OH) 2D), weight, and lumbar spine bone mineral density (LSBMD) were measured in 138 subjects with CF (5–56 years) and 138 control subjects (5–48 years). FEV 1, presence of CF liver disease (CFLD) and hospital admissions were recorded in those with CF. Results: Serum vitamin A level was lower in CF subjects than in controls (mean, 95% CI: 1.29, 1.0–1.37 vs. 1.80, 1.7–1.87 μmol/l, p<0.0001), and inversely correlated with CRP ( r s=−0.37, p<0.0001). CF subjects with low vitamin A (45%) level had poorer FEV 1, weight z-score, LSBMD z-score, and higher CRP compared with those with normal levels. In the CF group CRP, vitamin E, 1,25(OH) 2D, presence of CFLD, admissions, and age were associated with vitamin A level. Conclusions: Serum vitamin A is negatively associated with CRP in subjects with CF, consistent with normal population studies. It is important to distinguish between low serum vitamin A associated with the inflammatory response and that due to poor nutritional stores. The role of vitamin A in CF warrants further study, in the contexts both of chronic recurrent inflammatory disease and acute pulmonary exacerbation.