Ina Danquah1, C Lydia Dobrucky2, Laura K Frank3, Andrea Henze2, Yaw A Amoako4, George Bedu-Addo4, Jens Raila2, Matthias B Schulze3, Frank P Mockenhaupt5, Florian J Schweigert2. 1. Department of Molecular Epidemiology, German Institute of Human Nutrition Potsdam-Rebruecke, Nuthetal, Germany; ina.danquah@dife.de. 2. Department of Physiology and Pathophysiology, Institute of Nutritional Science, University of Potsdam, Potsdam, Germany; 3. Department of Molecular Epidemiology, German Institute of Human Nutrition Potsdam-Rebruecke, Nuthetal, Germany; 4. School of Medical Science, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana; and. 5. Institute of Tropical Medicine and International Health, Charité-Universitaetsmedizin Berlin, Berlin, Germany.
Abstract
BACKGROUND: Sub-Saharan Africa is facing a double burden of malnutrition: vitamin A deficiency (VAD) prevails, whereas the nutrition-related chronic conditions type 2 diabetes (T2D) and hypertension are emerging. Serum retinol—a VAD marker—increases in kidney disease and decreases in inflammation, which can partly be attributed to alterations in the vitamin A-transport proteins retinol-binding protein 4 (RBP4) and prealbumin. Kidney dysfunction and inflammation commonly accompany T2D and hypertension. OBJECTIVE: Among urban Ghanaians, we investigated the associations of T2D and hypertension with serum retinol as well as the importance of kidney function and inflammation in this regard. DESIGN: A hospital-based, case-control study in individuals for risk factors of T2D, hypertension, or both was conducted in Kumasi, Ghana (328 controls, 197 with T2D, 354 with hypertension, and 340 with T2D plus hypertension). In 1219 blood samples, serum retinol, RBP4, and prealbumin were measured. Urinary albumin and estimated glomerular filtration rate (eGFR) defined kidney function. C-reactive protein (CRP) >5 mg/L indicated inflammation. We identified associations of T2D and hypertension with retinol by linear regression and calculated the contribution of RBP4, prealbumin, urinary albumin, eGFR, and CRP to these associations as the percentages of the explained variance of retinol. RESULTS: VAD (retinol <1.05 μmol/L) was present in 10% of this predominantly female, middle-aged, overweight, and deprived population. Hypertension, but not T2D, was positively associated with retinol (β: 0.12; 95% CI: 0.08, 0.17), adjusted for age, sex, socioeconomic factors, anthropometric measurements, and lifestyle. In addition to RBP4 (72%) and prealbumin (22%), the effect of increased retinol on individuals with hypertension was mainly attributed to impaired kidney function (eGFR: 30%; urinary albumin: 5%) but not to inflammation. CONCLUSIONS: In patients with hypertension, VAD might be underestimated because of increased serum retinol in the context of kidney dysfunction. Thus, the interpretation of serum retinol in sub-Saharan Africa should account for hypertension status.
BACKGROUND: Sub-Saharan Africa is facing a double burden of malnutrition: vitamin A deficiency (VAD) prevails, whereas the nutrition-related chronic conditions type 2 diabetes (T2D) and hypertension are emerging. Serum retinol—a VAD marker—increases in kidney disease and decreases in inflammation, which can partly be attributed to alterations in the vitamin A-transport proteins retinol-binding protein 4 (RBP4) and prealbumin. Kidney dysfunction and inflammation commonly accompany T2D and hypertension. OBJECTIVE: Among urban Ghanaians, we investigated the associations of T2D and hypertension with serum retinol as well as the importance of kidney function and inflammation in this regard. DESIGN: A hospital-based, case-control study in individuals for risk factors of T2D, hypertension, or both was conducted in Kumasi, Ghana (328 controls, 197 with T2D, 354 with hypertension, and 340 with T2D plus hypertension). In 1219 blood samples, serum retinol, RBP4, and prealbumin were measured. Urinary albumin and estimated glomerular filtration rate (eGFR) defined kidney function. C-reactive protein (CRP) >5 mg/L indicated inflammation. We identified associations of T2D and hypertension with retinol by linear regression and calculated the contribution of RBP4, prealbumin, urinary albumin, eGFR, and CRP to these associations as the percentages of the explained variance of retinol. RESULTS: VAD (retinol <1.05 μmol/L) was present in 10% of this predominantly female, middle-aged, overweight, and deprived population. Hypertension, but not T2D, was positively associated with retinol (β: 0.12; 95% CI: 0.08, 0.17), adjusted for age, sex, socioeconomic factors, anthropometric measurements, and lifestyle. In addition to RBP4 (72%) and prealbumin (22%), the effect of increased retinol on individuals with hypertension was mainly attributed to impaired kidney function (eGFR: 30%; urinary albumin: 5%) but not to inflammation. CONCLUSIONS: In patients with hypertension, VAD might be underestimated because of increased serum retinol in the context of kidney dysfunction. Thus, the interpretation of serum retinol in sub-Saharan Africa should account for hypertension status.
Authors: Marie Alicke; Justice K Boakye-Appiah; Inusah Abdul-Jalil; Andrea Henze; Markus van der Giet; Matthias B Schulze; Florian J Schweigert; Frank P Mockenhaupt; George Bedu-Addo; Ina Danquah Journal: PLoS One Date: 2017-07-20 Impact factor: 3.240
Authors: Thomas Olsen; Kathrine J Vinknes; Rune Blomhoff; Vegard Lysne; Øivind Midttun; Indu Dhar; Per M Ueland; Gard F T Svingen; Eva K R Pedersen; Christian A Drevon; Helga Refsum; Ottar K Nygård Journal: Eur J Nutr Date: 2019-09-09 Impact factor: 5.614