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). FEV1, 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 FEV1, 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.