Serum Retinol And Retinol Binding Protein-4 Levels In Patients With Chronic Obstructive Pulmonary Disease And Their Relationship To Nutritional Status

ObjectiveTo determine the serum retinol(vitamin A) and retinol binding protein-4(RBP₄) levels in 110 patients with the stable phase of chronic obstructive pulmonary disease (COPD) and 90 healthy controls. To investigate their relationship to nutritional status and pulmonary function as well as their role in COPD.MethodsNutritional parameters and pulmonary function, including body mass index (BMI), percentage of ideal body weight(IBW%), triceps skin-fold thickness(TSF), mid-upper arm circumference(MAC), the forced expiratory volume in one second(FEV₁), forced vital capacity(FVC), FEV₁% predicted, FEV₁/FVC were determined in 110 patients with the stable phase of COPD and 90 healthy controls. The serum retinol of aboved study subjects were determined by high-performance liquid chromatography(HPLC). The serum retinol binding protein-4 levels in 62 stable COPD patients and 20 healthy controls were measured by enzyme-linked immunosorbent assay (ELISA). Correlated factors of the serum retinol and retinol binding protein-4 were analyzed .ResultsThe resum retinol and RBP₄ levels in COPD patients(275.18±11.36ug/l and 7.39±2.64ug/ml respectively) were significantly lower than those in the healthy controls(337.57±12.82ug/l and 11.4l±4.05ug/ml respectively, all p<0.01); The serum retinol and RBP₄ levels in those with malnutrition of COPD (246.31±18.35ug/l and 6.37±0.97ug/ml individually)were significantly lower than those without malnutrition of COPD (289.81±14.16ug/l and 8.18±3.21ug/ml; individually p<0.05 and p<0.01); The resum retinol and RBP4 levels in COPD patients without malnutrition (respectively 289.81±14.16ug/l vs 8.18±3.21ug/ml)were significantly lower than those in the healthy controls (respectively 337.57±12.82ug/l and 11.41±4.05ug/ml; p<0.05 vs p<0.01). In a multiple stepwise regression analysis, only body mass index(BMI) and mid-upper arm muscle circumference(MAMC) were independent influencing factors of the serum retinol and RBP₄.Conclusion1. The serum retinol and RBP4 levels were decreased significantly in the stable COPD patients.2. The serum retinol and RBP4 levels were associated with nutritional status in the stable COPD patients. The worse nutritional status, the lower significantly were the serum retinol and RBP₄ levels in COPD patients.3. The serum retinol and RBP4 levels were still significantly decreased in COPD patients without malnutrition. It suggests that the changes of the serum retinol and RBP₄ levels are not all due to malnutrition. The actual clinical significance needed to be further explored.