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Azupogo F, Abizari AR, Feskens EJM, Verhoef H, Brouwer ID. Ten2Twenty-Ghana: a randomised controlled trial on the efficacy of multiple micronutrient-fortified biscuits on the micronutrient status of adolescent girls. Br J Nutr 2024; 131:707-719. [PMID: 37795629 PMCID: PMC10803820 DOI: 10.1017/s0007114523002234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 09/23/2023] [Accepted: 10/02/2023] [Indexed: 10/06/2023]
Abstract
Adolescent girls are an important target group for micronutrient interventions particularly in Sub-Saharan Africa where adolescent pregnancy and micronutrient deficiencies are common. When consumed in sufficient amounts and at levels appropriate for the population, fortified foods may be a useful strategy for this group, but little is known about their effectiveness and timing (regarding menarche), particularly in resource-poor environments. We evaluated the effect of consuming multiple micronutrient-fortified biscuits (MMB), sold in the Ghanaian market, 5 d/week for 26 weeks compared with unfortified biscuits (UB) on the micronutrient status of female adolescents. We also explored to what extent the intervention effect varied before or after menarche. Ten2Twenty-Ghana was a 26-week double-blind, randomised controlled trial among adolescent girls aged 10-17 years (n 621) in the Mion District, Ghana. Biomarkers of micronutrient status included concentrations of Hb, plasma ferritin (PF), soluble transferrin receptor (TfR) and retinol-binding protein (RBP), including body-iron stores. Intention-to-treat analysis was supplemented by protocol-specific analysis. We found no effect of the intervention on PF, TfR and RBP. MMB consumption did not affect anaemia and micronutrient deficiencies at the population level. MMB consumption increased the prevalence of vitamin A deficiency by 6·2 % (95 % CI (0·7, 11·6)) among pre-menarche girls when adjusted for baseline micronutrient status, age and height-for-age Z-score, but it decreased the prevalence of deficient/low vitamin A status by -9·6 % (95 % CI (-18·9, -0·3)) among post-menarche girls. Consuming MMB available in the market did not increase iron status in our study, but reduced the prevalence of deficient/low vitamin A status in post-menarcheal girls.
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Affiliation(s)
- Fusta Azupogo
- Department of Family and Consumer Sciences, Faculty of Agriculture, Food and Consumer Sciences, University for Development Studies, Tamale, 1882, Ghana
- Institute for Global Nutrition, University of California, Davis, USA
| | - Abdul-Razak Abizari
- Formerly of the Department of Nutritional Sciences, School of Allied Health Sciences, University for Development Studies, Tamale, Ghana
| | - Edith J. M. Feskens
- Division of Human Nutrition and Health, Wageningen University and Research, Wageningen, The Netherlands
| | - Hans Verhoef
- Division of Human Nutrition and Health, Wageningen University and Research, Wageningen, The Netherlands
| | - Inge D. Brouwer
- Division of Human Nutrition and Health, Wageningen University and Research, Wageningen, The Netherlands
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2
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Sombié OO, Zeba AN, Somé JW, Kazienga A, Grahn M, Tanumihardjo SA, De Henauw S, Abbeddou S. A comparative study on indicators of vitamin A status and risk factors for sensitivity and specificity of the methods to detect vitamin A deficiency. Nutr Metab (Lond) 2023; 20:49. [PMID: 37974246 PMCID: PMC10652566 DOI: 10.1186/s12986-023-00768-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Accepted: 11/07/2023] [Indexed: 11/19/2023] Open
Abstract
BACKGROUND Serum retinol (SR) and retinol-binding protein (RBP) are commonly used indicators, but they are affected by infections and inflammation. This study aimed to assess the sensitivity and specificity of VA indicators to detect vitamin A deficiency (VAD) in 36-59-month-old children living in a rural area in Burkina Faso. METHODS In a community-based study, two cross-sectional surveys were carried out from November 2016 to September 2017 in the health district of Dandé in Burkina Faso. The surveys included 115 children 36-59 months old. Indicators of VA and inflammation assessed in all children included SR, RBP and total liver VA reserves (TLR) estimated by retinol isotope dilution, and inflammation markers (C-reactive protein (CRP) and alpha 1-acid glycoprotein (AGP)). We calculated the sensitivity, specificity, positive and negative predictive values. In addition, the effects of inflammation, helminth infection, and season on sensitivity and specificity were assessed. RESULTS The prevalence of VAD assessed by SR (< 0.7 µmol/L), RBP (< 0.7 µmol/L), and TLR (< 0.1 µmol/g liver) were, respectively, 30.9%, 33.3%, and 0%. Compared to TLR, the specificity, positive predictive value, and negative predictive value of SR were 71.1%, 0%, and 100%, and of RBP, were 68.9%, 0%, and 100%, respectively. The sensitivity was indeterminable for SR and RBP. The specificity of SR and RBP was lower during the dry season. Elevated CRP (> 5.0 mg/L) and AGP (> 1.0 g/L) were detected in 1.9% and 28.6% of children, respectively. The adjustment of VA indicators for inflammation improved SR's specificity to 75.9% and decreased RBP's specificity to 67.8%. CONCLUSION No cases of VAD were identified by TLR. However, (inflammation-adjusted) SR and RBP had varying accuracy in the estimation of VAD. TRIAL REGISTRATION The study was registered, retrospectively, on 22 March 2018 as a clinical trial with the Pan African Clinical Trials Registry under the number Cochrane South Africa; PACTR201803002999356.
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Affiliation(s)
- Olivier O Sombié
- Unité Nutrition et Maladies Métaboliques, Institut de Recherche en Sciences de la Santé/Direction Régionale de l'Ouest, Bobo-Dioulasso, Burkina Faso.
- Department of Public Health and Primary Care, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium.
| | - Augustin N Zeba
- Unité Nutrition et Maladies Métaboliques, Institut de Recherche en Sciences de la Santé/Direction Régionale de l'Ouest, Bobo-Dioulasso, Burkina Faso
| | - Jérome W Somé
- Unité Nutrition et Maladies Métaboliques, Institut de Recherche en Sciences de la Santé/Direction Générale, Ouagadougou, Burkina Faso
| | - Adama Kazienga
- Department of Translational Physiology, Infectiology and Public Health, Faculty of Veterinary Medicine, Ghent University, Ghent, Belgium
| | - Michael Grahn
- Department of Nutritional Sciences, University of Wisconsin-Madison, Madison, USA
| | | | - Stefaan De Henauw
- Department of Public Health and Primary Care, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Souheila Abbeddou
- Department of Public Health and Primary Care, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
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Neyer PJ, Kaboré B, Nakas CT, Hartmann B, Post A, Diallo S, Tinto H, Hammerer-Lercher A, Largiadèr CR, van der Ven AJ, Huber AR. Exploring the host factors affecting asymptomatic Plasmodium falciparum infection: insights from a rural Burkina Faso study. Malar J 2023; 22:252. [PMID: 37658365 PMCID: PMC10474782 DOI: 10.1186/s12936-023-04686-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 08/23/2023] [Indexed: 09/03/2023] Open
Abstract
BACKGROUND Asymptomatic Plasmodium falciparum parasitaemia forms a reservoir for the transmission of malaria disease in West Africa. Certain haemoglobin variants are known to protect against severe malaria infection. However, data on the potential roles of haemoglobin variants and nongenetic factors in asymptomatic malaria infection is scarce and controversial. Therefore, this study investigated the associations of iron homeostasis, inflammation, nutrition, and haemoglobin mutations with parasitaemia in an asymptomatic cohort from a P. falciparum-endemic region during the high transmission season. METHODS A sub-study population of 688 asymptomatic individuals (predominantly children and adolescents under 15 years, n = 516) from rural Burkina Faso previously recruited by the NOVAC trial (NCT03176719) between June and October 2017 was analysed. Parasitaemia was quantified with conventional haemocytometry. The haemoglobin genotype was determined by reverse hybridization assays targeting a selection of 21 HBA and 22 HBB mutations. Demographics, inflammatory markers (interleukins 6 and 10, hepcidin), nutritional status (mid upper-arm circumference and body mass index), and anaemia (total haemoglobin, ferritin, soluble transferrin receptor) were assessed as potential predictors through logistic regression. RESULTS Malaria parasites were detected in 56% of subjects. Parasitaemia was associated most strongly with malnutrition. The effect size increased with malnutrition severity (OR = 6.26, CI95: 2.45-19.4, p < 0.001). Furthermore, statistically significant associations (p < 0.05) with age, cytokines, hepcidin and heterozygous haemoglobin S were observed. CONCLUSIONS According to these findings, asymptomatic parasitaemia is attenuated by haemoglobin S, but not by any of the other detected genotypes. Aside from evidence for slight iron imbalance, overall undernutrition was found to predict parasitaemia; thus, further investigations are required to elucidate causality and inform strategies for interventions.
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Affiliation(s)
- Peter J Neyer
- Institute of Laboratory Medicine, Kantonsspital Aarau, Aarau, Switzerland.
- Graduate School for Cellular & Biomedical Sciences, University of Bern, Bern, Switzerland.
- Department of Clinical Chemistry, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.
| | - Bérenger Kaboré
- Department of Internal Medicine, Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands
- IRSS/Clinical Research Unit of Nanoro (CRUN), Nanoro, Burkina Faso
| | - Christos T Nakas
- Department of Clinical Chemistry, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- Laboratory of Biometry, Department of Agriculture Crop, Production and Rural Environment, University of Thessaly, Volos, Greece
| | - Britta Hartmann
- Institute of Laboratory Medicine, Kantonsspital Aarau, Aarau, Switzerland
| | - Annelies Post
- Department of Internal Medicine, Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Salou Diallo
- IRSS/Clinical Research Unit of Nanoro (CRUN), Nanoro, Burkina Faso
| | - Halidou Tinto
- IRSS/Clinical Research Unit of Nanoro (CRUN), Nanoro, Burkina Faso
| | | | - Carlo R Largiadèr
- Graduate School for Cellular & Biomedical Sciences, University of Bern, Bern, Switzerland
- Department of Clinical Chemistry, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Andre J van der Ven
- Department of Internal Medicine, Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Andreas R Huber
- Private University in the Principality of Liechtenstein, Triesen, Principality of Liechtenstein
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Sandalinas F, Filteau S, Joy EJM, Segovia de la Revilla L, MacDougall A, Hopkins H. Measuring the impact of malaria infection on indicators of iron and vitamin A status: a systematic literature review and meta-analysis. Br J Nutr 2023; 129:87-103. [PMID: 35260210 PMCID: PMC9816655 DOI: 10.1017/s0007114522000757] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 02/17/2022] [Accepted: 02/28/2022] [Indexed: 01/21/2023]
Abstract
Inflammation and infections such as malaria affect estimates of micronutrient status. Medline, Embase, Web of Science, Scopus and the Cochrane library were searched to identify studies reporting mean concentrations of ferritin, hepcidin, retinol or retinol binding protein in individuals with asymptomatic or clinical malaria and healthy controls. Study quality was assessed using the US National Institute of Health tool. Random effects meta-analyses were used to generate summary mean differences. In total, forty-four studies were included. Mean ferritin concentrations were elevated by: 28·2 µg/l (95 % CI 15·6, 40·9) in children with asymptomatic malaria; 28·5 µg/l (95 % CI 8·1, 48·8) in adults with asymptomatic malaria; and 366 µg/l (95 % CI 162, 570) in children with clinical malaria compared with individuals without malaria infection. Mean hepcidin concentrations were elevated by 1·52 nmol/l (95 % CI 0·92, 2·11) in children with asymptomatic malaria. Mean retinol concentrations were reduced by: 0·11 µmol/l (95 % CI -0·22, -0·01) in children with asymptomatic malaria; 0·43 µmol/l (95 % CI -0·71, -0·16) in children with clinical malaria and 0·73 µmol/l (95 % CI -1·11, -0·36) in adults with clinical malaria. Most of these results were stable in sensitivity analyses. In children with clinical malaria and pregnant women, difference in ferritin concentrations were greater in areas with higher transmission intensity. We conclude that biomarkers of iron and vitamin A status should be statistically adjusted for malaria and the severity of infection. Several studies analysing asymptomatic infections reported elevated ferritin concentrations without noticeable elevation of inflammation markers, indicating a need to adjust for malaria status in addition to inflammation adjustments.
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Affiliation(s)
- Fanny Sandalinas
- Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, UK
| | - Suzanne Filteau
- Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, UK
| | - Edward J. M. Joy
- Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, UK
| | | | - Amy MacDougall
- Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, UK
| | - Heidi Hopkins
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
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5
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Brown KH, Atkin R, Gorstein J, Osendarp SJM. Comments on article by Pullakhandam et al: Reference cut-offs to define low serum zinc concentrations in healthy 1-19 year old Indian children and adolescents. Eur J Clin Nutr 2022; 76:1204-1205. [PMID: 35804149 PMCID: PMC9352568 DOI: 10.1038/s41430-022-01174-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 05/06/2022] [Accepted: 05/26/2022] [Indexed: 11/09/2022]
Affiliation(s)
- Kenneth H. Brown
- grid.27860.3b0000 0004 1936 9684Department of Nutrition and Institute for Global Nutrition, University of California Davis, Davis, CA USA ,The Micronutrient Forum, Washington DC, USA
| | - Reed Atkin
- The Micronutrient Forum, Washington DC, USA
| | - Jonathan Gorstein
- grid.418309.70000 0000 8990 8592The Bill & Melinda Gates Foundation, Seattle, WA USA ,grid.34477.330000000122986657Department of Global Health, University of Washington, Seattle, WA USA
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Afolami I, Mwangi MN, Samuel F, Boy E, Ilona P, Talsma EF, Feskens E, Melse-Boonstra A. Daily consumption of pro-vitamin A biofortified (yellow) cassava improves serum retinol concentrations in preschool children in Nigeria: a randomized controlled trial. Am J Clin Nutr 2020; 113:221-231. [PMID: 33184647 PMCID: PMC7779233 DOI: 10.1093/ajcn/nqaa290] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 09/22/2020] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Vitamin A deficiency is a public health problem in sub-Saharan Africa. Pro-vitamin A biofortified (yellow) cassava has the potential to contribute significantly to improve vitamin A status, especially in populations that are difficult to reach with other strategies. OBJECTIVES The study aimed at determining the efficacy of biofortified cassava to improve vitamin A status of Nigerian preschool children. METHODS An open-label randomized controlled trial was conducted in southwestern Nigeria. In total, 176 preschool children (aged 3-5 y) were randomized into 2 parallel arms comprising an experimental group (n = 88), fed foods prepared from biofortified (yellow) cassava, and a control group (n = 88), fed foods prepared from white cassava, twice a day, 6 d a week for 93 d. RESULTS A total of 159 children completed the trial (yellow cassava group, n = 80; white cassava group, n = 79). Children consumed 221 and 74 µg/d retinol activity equivalents from intervention foods in the yellow and white cassava groups, respectively. The treatment effect on serum retinol concentrations at the end of the feeding trial was 0.06 µmol/L (95% CI: 0.004, 0.124 µmol/L), after adjustment for baseline retinol concentrations, inflammation, and asymptomatic malaria status. No significant treatment effects were detected for serum β-carotene (adjusted effect: 3.9%; 95% CI: -0.6%, 8.6%) and gut permeability (adjusted effect: 0.002; 95% CI: -0.089, 0.092), but a significant effect was detected for hemoglobin concentrations (adjusted effect: 3.08 g/L; 95% CI: 0.38, 5.78 g/L). CONCLUSIONS Daily consumption of β-carotene from biofortified cassava improved serum retinol and hemoglobin concentrations modestly in Nigerian preschool children. This study was registered with clinicaltrials.gov as NCT02627222.
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Affiliation(s)
- Ibukun Afolami
- Division of Human Nutrition and Health, Wageningen University and Research, Wageningen, Netherlands,Department of Human Nutrition and Dietetics, University of Ibadan, Ibadan, Nigeria
| | - Martin N Mwangi
- Division of Human Nutrition and Health, Wageningen University and Research, Wageningen, Netherlands,Training and Research Unit of Excellence, College of Medicine, University of Malawi, Blantyre, Malawi
| | - Folake Samuel
- Department of Human Nutrition and Dietetics, University of Ibadan, Ibadan, Nigeria
| | | | | | - Elise F Talsma
- Division of Human Nutrition and Health, Wageningen University and Research, Wageningen, Netherlands
| | - Edith Feskens
- Division of Human Nutrition and Health, Wageningen University and Research, Wageningen, Netherlands
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van Griensven J, Cnops L, De Weggheleire A, Declercq S, Bottieau E. Point-of-Care Biomarkers to Guide Antibiotic Prescription for Acute Febrile Illness in Sub-Saharan Africa: Promises and Caveats. Open Forum Infect Dis 2020; 7:ofaa260. [PMID: 32818139 PMCID: PMC7423291 DOI: 10.1093/ofid/ofaa260] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 06/26/2020] [Indexed: 01/21/2023] Open
Abstract
Empiric malaria treatment in Sub-Saharan Africa has significantly decreased with the scaling-up of malaria rapid diagnostic tests; this coincided with a pronounced increase in empiric antibiotic prescriptions. In high-income countries, guidance for antibiotic prescriptions using biomarkers such as C-reactive protein (CRP) and procalcitonin (PCT) has reduced antibiotic use while safe-guarding patient safety. Importantly, several low-cost point-of-care CRP/PCT tests are currently available. However, only a few studies on the role of CRP/PCT in differentiating bacterial vs viral infections in acute febrile illness have been conducted in Sub-Saharan Africa. Studies from Central and West Africa (most of which is malaria-endemic) are particularly scarce, and only 1 has included adults. The evidence base for point-of-care use of CRP/PCT biomarkers in acute fever in Sub-Saharan Africa should be urgently built. Before engaging in clinical trials to assess clinical impact, pilot studies should be conducted to address key knowledge gaps including recommended CRP/PCT cutoff values and the effect of malaria coinfection.
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McDonald CM, Suchdev PS, Krebs NF, Hess SY, Wessells KR, Ismaily S, Rahman S, Wieringa FT, Williams AM, Brown KH, King JC. Adjusting plasma or serum zinc concentrations for inflammation: Biomarkers Reflecting Inflammation and Nutritional Determinants of Anemia (BRINDA) project. Am J Clin Nutr 2020; 111:927-937. [PMID: 32266402 PMCID: PMC7138668 DOI: 10.1093/ajcn/nqz304] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 11/14/2019] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND The accurate estimation of zinc deficiency at the population level is important, as it guides the design, targeting, and evaluation of nutrition interventions. Plasma or serum zinc concentration (PZC) is recommended to estimate zinc nutritional status; however, concentrations may decrease in the presence of inflammation. OBJECTIVES We aimed to assess the relation between PZC and inflammation in preschool children (PSC; 6-59 mo) and nonpregnant women of reproductive age (WRA; 15-49 y), and to compare different inflammation adjustment approaches, if adjustment is warranted. METHODS Cross-sectional data from 13 nationally representative surveys (18,859 PSC, 22,695 WRA) from the Biomarkers Reflecting Inflammation and Nutritional Determinants of Anemia (BRINDA) project were analyzed. Correlation and decile analyses were conducted, and the following 3 adjustment methods were compared if a consistent negative association between PZC and C-reactive protein (CRP) or α-1-acid glycoprotein (AGP) was observed: 1) exclude individuals with CRP > 5 mg/L or AGP > 1 g/L; 2) apply arithmetic correction factors; and 3) use the BRINDA regression correction (RC) approach. RESULTS In 6 of 12 PSC surveys, the estimated prevalence of zinc deficiency increased with increasing CRP deciles, and to a lesser extent, with increasing AGP deciles. In WRA, the association of PZC with CRP and AGP was weak and inconsistent. In the 6 PSC surveys in which adjustment methods were compared, application of RC reduced the estimated prevalence of zinc deficiency by a median of 11 (range: 4-18) percentage points, compared with the unadjusted prevalence. CONCLUSIONS Relations between PZC and inflammatory markers were inconsistent, suggesting that correlation and decile analyses should be conducted before applying any inflammation adjustments. In populations of PSC that exhibit a significant negative association between PZC and CRP or AGP, application of the RC approach is supported. At this time, there is insufficient evidence to warrant inflammation adjustment in WRA.
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Affiliation(s)
- Christine M McDonald
- Children's Hospital Oakland Research Institute, Oakland, CA, USA
- Department of Pediatrics, School of Medicine, University of California, San Francisco, CA, USA
- Address correspondence to CMM (e-mail: )
| | - Parminder S Suchdev
- Rollins School of Public Health, Emory University, Atlanta, GA, USA
- Nutrition Branch, CDC, Atlanta, GA, USA
| | - Nancy F Krebs
- Section of Nutrition, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA
| | - Sonja Y Hess
- Department of Nutrition, University of California, Davis, CA, USA
| | - K Ryan Wessells
- Department of Nutrition, University of California, Davis, CA, USA
| | - Sanober Ismaily
- Rollins School of Public Health, Emory University, Atlanta, GA, USA
| | - Sabuktagin Rahman
- International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh
- School of Medicine, Griffith University, Gold Coast, Queensland, Australia
| | | | - Anne M Williams
- Rollins School of Public Health, Emory University, Atlanta, GA, USA
- Nutrition Branch, CDC, Atlanta, GA, USA
- McKing Consulting Corporation, Atlanta, GA, USA
| | - Kenneth H Brown
- Department of Nutrition, University of California, Davis, CA, USA
| | - Janet C King
- Children's Hospital Oakland Research Institute, Oakland, CA, USA
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Abstract
BACKGROUND Iron deficiency (ID) is a major public health burden in African children and accurate prevalence estimates are important for effective nutritional interventions. However, ID may be incorrectly estimated in Africa because most measures of iron status are altered by inflammation and infections such as malaria. Through the current study, we have assessed different approaches to the prediction of iron status and estimated the burden of ID in African children. METHODS We assayed iron and inflammatory biomarkers in 4853 children aged 0-8 years from Kenya, Uganda, Burkina Faso, South Africa, and The Gambia. We described iron status and its relationship with age, sex, inflammation, and malaria parasitemia. We defined ID using the WHO guideline (ferritin < 12 μg/L or < 30 μg/L in the presence of inflammation in children < 5 years old or < 15 μg/L in children ≥ 5 years old). We compared this with a recently proposed gold standard, which uses regression-correction for ferritin levels based on the relationship between ferritin levels, inflammatory markers, and malaria. We further investigated the utility of other iron biomarkers in predicting ID using the inflammation and malaria regression-corrected estimate as a gold standard. RESULTS The prevalence of ID was highest at 1 year of age and in male infants. Inflammation and malaria parasitemia were associated with all iron biomarkers, although transferrin saturation was least affected. Overall prevalence of WHO-defined ID was 34% compared to 52% using the inflammation and malaria regression-corrected estimate. This unidentified burden of ID increased with age and was highest in countries with high prevalence of inflammation and malaria, where up to a quarter of iron-deficient children were misclassified as iron replete. Transferrin saturation < 11% most closely predicted the prevalence of ID according to the regression-correction gold standard. CONCLUSIONS The prevalence of ID is underestimated in African children when defined using the WHO guidelines, especially in malaria-endemic populations, and the use of transferrin saturation may provide a more accurate approach. Further research is needed to identify the most accurate measures for determining the prevalence of ID in sub-Saharan Africa.
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Wessells KR, Peerson JM, Brown KH. Within-individual differences in plasma ferritin, retinol-binding protein, and zinc concentrations in relation to inflammation observed during a short-term longitudinal study are similar to between-individual differences observed cross-sectionally. Am J Clin Nutr 2019; 109:1484-1492. [PMID: 30976780 DOI: 10.1093/ajcn/nqz014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Accepted: 01/21/2019] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Cross-sectional (CS) surveys indicate that individuals with acute inflammation have higher plasma ferritin (pF), and lower retinol-binding protein (RBP) and zinc (pZn) concentrations than those without. In populations with a high burden of infection, correction factors (CFs) or regression corrections (RCs) are applied to biomarkers to estimate the prevalence of micronutrient (MN) deficiencies adjusted for inflammation. This assumes that individuals with and without inflammation have the same nutritional status, which may not be the case. OBJECTIVES The aim of this study was to investigate relations between short-term, longitudinal within-individual changes in acute phase proteins (C-reactive protein [CRP], α-1-acid glycoprotein [AGP]) and biomarkers of MN status (pF, soluble transferrin receptor [sTfR], RBP, and pZn), and compare them to CS differences. METHODS Two blood samples were obtained 21 d apart from 451 asymptomatic Burkinabé children aged 6-23 mo. To calculate CFs, inflammation was defined as CRP >5 mg/L or AGP >1 g/L, or both. The RC approach adjusted MN biomarkers to a presumably healthy reference point within the study population (10th percentile CRP or AGP concentration). CS CFs and RCs were estimated from a naive regression model, treating observations from the same children as independent. Longitudinal CFs and RCs, to estimate effects of within-individual changes in CRP and/or AGP, were estimated from general linear models, accounting for repeated measures. RESULTS In CS models, geometric mean pF and sTfR concentrations were 8-340% greater, and RBP and pZn 2-18% lower, in children with inflammation than those without. Except for sTfR, biomarker concentrations differed in the same direction and by similar magnitude within individuals whose inflammation status changed during the observation period. Although geometric mean MN concentrations differed significantly when adjusted with CS compared with longitudinal models, the estimated prevalence of MN deficiencies in CS and longitudinally adjusted models was similar. CONCLUSIONS The CF and RC approaches to adjust MN biomarkers for inflammation between individuals in CS surveys are valid approaches for data collection and programmatic decisions in comparable populations. This study was registered at clinicaltrials.gov as NCT00944853.
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Affiliation(s)
- K Ryan Wessells
- Program in International and Community Nutrition, Department of Nutrition, University of California, Davis, CA
| | - Janet M Peerson
- Program in International and Community Nutrition, Department of Nutrition, University of California, Davis, CA
| | - Kenneth H Brown
- Program in International and Community Nutrition, Department of Nutrition, University of California, Davis, CA.,Nutrition and Global Development, Bill & Melinda Gates Foundation, Seattle, WA
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11
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Barffour MA, Schulze KJ, Coles CL, Chileshe J, Kalungwana N, Arguello M, Siamusantu W, Moss WJ, West KP, Palmer AC. Comparability of Inflammation-Adjusted Vitamin A Deficiency Estimates and Variance in Retinol Explained by C-Reactive Protein and α 1-Acid Glycoprotein during Low and High Malaria Transmission Seasons in Rural Zambian Children. Am J Trop Med Hyg 2018; 98:334-343. [PMID: 29165226 DOI: 10.4269/ajtmh.17-0130] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Inflammation-induced hyporetinolemia (IIH), a reduction in serum retinol (SR) during inflammation, may bias population estimates of vitamin A deficiency (VAD). The optimal adjustment for IIH depends on the type and extent of inflammation. In rural Zambian children (4-8 years, N = 886), we compared three models for defining inflammation: α-1-acid glycoprotein (AGP) only (inflammation present if > 1 g/L or normal if otherwise), C-reactive protein (CRP) only (moderate inflammation, 5-15 mg/L; high inflammation, > 15 mg/L; or normal if otherwise) and a combined model using both AGP and CRP to delineate stages of infectious episode. Models were compared with respect to 1) the variance in SR explained and 2) comparability of inflammation-adjusted VAD estimated in low and high malaria seasons. Linear regression was used to estimate the variance in SR explained by each model and in estimating the adjustment factors used in generating adjusted VAD (retinol < 0.7 μmol/L). The variance in SR explained were 2% (AGP-only), 11% (CRP-only), and 11% (AGP-CRP) in the low malaria season; and 2% (AGP-only), 15% (CRP-only), and 12% (AGP-CRP) in the high malaria season. Adjusted VAD estimates in the low and high malaria seasons differed significantly for the AGP (8.2 versus 13.1%) and combined (5.5 versus 9.1%) models but not the CRP-only model (6.1 versus 6.3%). In the multivariate regression, a decline in SR was observed with rising CRP (but not AGP), in both malaria seasons (slope = -0.06; P < 0.001). In this malaria endemic setting, CRP alone, as opposed to CRP and AGP, emerged as the most appropriate model for quantifying IIH.
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Affiliation(s)
- Maxwell A Barffour
- Department of International Health, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Baltimore, Maryland
| | - Kerry J Schulze
- Department of International Health, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Baltimore, Maryland
| | - Christian L Coles
- Department of International Health, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Baltimore, Maryland
| | | | | | - Margia Arguello
- Department of International Health, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Baltimore, Maryland
| | | | - William J Moss
- Department of International Health, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Baltimore, Maryland
| | - Keith P West
- Department of International Health, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Baltimore, Maryland
| | - Amanda C Palmer
- Department of International Health, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Baltimore, Maryland
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12
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Barffour MA, Schulze KJ, Coles CL, Chileshe J, Kalungwana N, Siamusantu W, Arguello M, Moss WJ, West KP, Palmer AC. Malaria exacerbates inflammation-associated elevation in ferritin and soluble transferrin receptor with only modest effects on iron deficiency and iron deficiency anaemia among rural Zambian children. Trop Med Int Health 2017; 23:53-62. [PMID: 29121448 DOI: 10.1111/tmi.13004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
OBJECTIVE In 4- to 8-year-old Zambian children (n = 744), we evaluated the effects of adjusting for inflammation (α1-acid glycoprotein >1 g/l), with or without additional adjustment for malaria, on prevalence estimates of iron deficiency (ID) and iron deficiency anaemia (IDA) during low malaria (LowM) and high malaria (HighM) transmission seasons. METHODS To estimate adjustment factors, children were classified as: (i) reference (malaria negative without inflammation), (ii) inflammation without malaria (I), (iii) malaria without inflammation (M) and (iv) inflammation with malaria (IM). We estimated the unadjusted ID or IDA prevalence, and then adjusted for inflammation alone (IDI or IDAI ) or inflammation and malaria (IDIM or IDAIM ). RESULTS Mean ferritin was 38 (reference), 45 (I), 43 (M) and 54 μg/l (IM) in LowM, increasing to 44, 56, 96 and 167 μg/l, respectively, in HighM. Corresponding mean sTfR was 6.4, 6.9, 7.9 and 8.4 mg/l in LowM, increasing to 8.2, 9.2. 8.7 and 9.7 mg/l in HighM. Ferritin-based ID, IDI and IDIM were 7.8%, 8.7% or 9.1%, respectively, in LowM and 4.6%, 10.0% or 11.7%, respectively, in HighM. Corresponding soluble transferrin receptor (sTfR)-based estimates were 27.0%, 24.1% and 19.1%, respectively, in LowM, increasing to 53.6%, 46.5% and 45.3%, respectively, in HighM. Additional adjustment for malaria resulted in a ~1- to 2-percentage point change in IDA, depending on biomarker and season. CONCLUSIONS In this population, malaria substantially increased ferritin and sTfR concentrations, with modest effects on ID and IDA prevalence estimates.
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Affiliation(s)
- Maxwell A Barffour
- Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA
| | - Kerry J Schulze
- Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA
| | - Christian L Coles
- Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA
| | | | | | | | - Margia Arguello
- Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA
| | - William J Moss
- Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA
| | - Keith P West
- Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA
| | - Amanda C Palmer
- Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA
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13
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Brindle E, Lillis L, Barney R, Hess SY, Wessells KR, Ouédraogo CT, Stinca S, Kalnoky M, Peck R, Tyler A, Lyman C, Boyle DS. Simultaneous assessment of iodine, iron, vitamin A, malarial antigenemia, and inflammation status biomarkers via a multiplex immunoassay method on a population of pregnant women from Niger. PLoS One 2017; 12:e0185868. [PMID: 28982133 PMCID: PMC5628875 DOI: 10.1371/journal.pone.0185868] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 09/20/2017] [Indexed: 11/24/2022] Open
Abstract
Deficiencies of vitamin A, iron, and iodine are major public health concerns in many low- and middle-income countries, but information on their status in populations is often lacking due to high costs and logistical challenges associated with assessing micronutrient status. Accurate, user-friendly, and low-cost analytical tools are needed to allow large-scale population surveys on micronutrient status. We present the expansion of a 7-plex protein microarray tool for the simultaneous measurement of up to seven biomarkers with relevance to the assessment of the key micronutrients iron, iodine, and vitamin A, and inflammation and malaria biomarkers: α-1-acid glycoprotein, C-reactive protein, ferritin, retinol binding protein 4, soluble transferrin receptor, thyroglobulin, and histidine-rich protein II. Assay performance was assessed using international reference standards and then verified by comparing the multiplexed and conventional immunoassay results on a training panel of plasma samples collected from US adults. These data were used to assign nominal concentrations to the calibrators of the assay to further improve performance which was then assessed by interrogating plasma samples from a cohort of pregnant women from Niger. The correlation between assays for each biomarker measured from this cohort was typically good, with the exception of thyroglobulin, and the sensitivity ranged from 74% to 93%, and specificity from 81% to 98%. The 7-Plex micronutrient assay has the potential for use as an affordable tool for population surveillance of vitamin A, iron, and iodine deficiencies as well as falciparum malarial parasitemia infectivity and inflammation. The assay is easy-to-use, requires minimal sample volume, and is scalable, rapid, and accurate—needing only a low-cost reader and basic equipment present in most reference laboratory settings and so may be employed by low and middle income countries for micronutrient surveillance to inform on status in key populations. Micronutrient deficiencies including iron, iodine, and vitamin A affect a significant portion of the world’s population. Efforts to assess the prevalence of these deficiencies in vulnerable populations are challenging, partly due to measurement tools that are inadequate for assessing multiple micronutrients in large-scale population surveys. We have developed a 7-plex immunoassay for the simultaneous measurement of seven biomarkers relevant to assessing iodine, iron, and vitamin A status, inflammation and Plasmodium falciparum parasitemia by measuring levels of thyroglobulin, ferritin, soluble transferrin receptor, retinol binding protein 4, α-1-acid glycoprotein, C-reactive protein, and histidine-rich protein II. This 7-plex immunoassay technique has potential as a rapid and effective tool for use in large-scale surveys and assessments of nutrition intervention programs in low- and middle-income countries.
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Affiliation(s)
- Eleanor Brindle
- Center for Studies in Demography and Ecology, University of Washington, Seattle, WA, United States of America
| | | | | | - Sonja Y. Hess
- Program in International and Community Nutrition, Department of Nutrition, University of California, Davis, CA, United States of America
| | - K. Ryan Wessells
- Program in International and Community Nutrition, Department of Nutrition, University of California, Davis, CA, United States of America
| | - Césaire T. Ouédraogo
- Program in International and Community Nutrition, Department of Nutrition, University of California, Davis, CA, United States of America
- Helen Keller International, Niamey, Niger
| | - Sara Stinca
- Laboratory of Human Nutrition, Swiss Federal Institute of Technology, Zurich, Switzerland
| | | | - Roger Peck
- PATH, Seattle, WA, United States of America
| | - Abby Tyler
- Quansys Biosciences, Logan, Utah, United States of America
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14
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Lombardo P, Vaucher P, Rarau P, Mueller I, Favrat B, Senn N. Hemoglobin Levels and the Risk of Malaria in Papua New Guinean Infants: A Nested Cohort Study. Am J Trop Med Hyg 2017; 97:1770-1776. [PMID: 29016324 DOI: 10.4269/ajtmh.17-0093] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Studies are available that assess the risk of malaria in accordance to the body's iron store and the systematic iron supplementation of preschool children. However, only a few studies evaluated the temporal association between hemoglobin and malaria and their results are opposing. A total of 1,650 3-month-old Papua New Guinean infants were enrolled in this study and followed-up for 12 months. The risk of malaria was assessed in all children every 3 months and with each episode of fever. The incidence of clinical malaria between 3 and 15 months of age was 249 cases per 1,000 infants per year. After adjustment for potential confounding factors, a decrease of 1 g/dL of hemoglobin was associated with a nonsignificant increase of 11% for risk of malaria infection (hazard ratio, 1.11, 95% confidence interval; CI, 0.99-1.25, P = 0.076). Only children with severe anemia (hemoglobin < 8.0 g/dL) at baseline were at higher risk of malaria infection (hazard ratio, 1.72, 95% CI, 1.08-2.76, P = 0.023) during the follow-up year compared with the control group (Hemoglobin > 10.0 g/dL). This association was not statistically significant if only clinical malaria episodes were taken into account (hazard ratio, 1.42, 95% CI, 0.77-2.61, P = 0.26). Our study suggests that infants with lower hemoglobin levels are not protected against malaria infection. Further research that examines the risk of malaria in relation to both hemoglobin and iron store levels would be important to better understand this complex interaction.
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Affiliation(s)
- Patrick Lombardo
- Institute of Family Medicine, University of Lausanne, Lausanne, Switzerland
| | - Paul Vaucher
- University Center of Legal Medicine, University Hospital Lausanne (CHUV), Lausanne, Switzerland.,School of Health Sciences Fribourg, University of Applied Sciences Western Switzerland (HES-SO), Fribourg, Switzerland
| | - Patricia Rarau
- Papua New Guinea Institute of Medical Research, Vector Borne Diseases Unit, Madang, Papua New Guinea
| | - Ivo Mueller
- Division of Population Health and Immunity, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
| | - Bernard Favrat
- Department of Ambulatory Care and Community Medicine, University of Lausanne, Lausanne, Switzerland
| | - Nicolas Senn
- Department of Ambulatory Care and Community Medicine, University of Lausanne, Lausanne, Switzerland.,Institute of Family Medicine, University of Lausanne, Lausanne, Switzerland
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15
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Engle-Stone R, Williams TN, Nankap M, Ndjebayi A, Gimou MM, Oyono Y, Tarini A, Brown KH, Green R. Prevalence of Inherited Hemoglobin Disorders and Relationships with Anemia and Micronutrient Status among Children in Yaoundé and Douala, Cameroon. Nutrients 2017; 9:E693. [PMID: 28671630 PMCID: PMC5537808 DOI: 10.3390/nu9070693] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Revised: 06/19/2017] [Accepted: 06/26/2017] [Indexed: 02/06/2023] Open
Abstract
Information on the etiology of anemia is necessary to design effective anemia control programs. Our objective was to measure the prevalence of inherited hemoglobin disorders (IHD) in a representative sample of children in urban Cameroon, and examine the relationships between IHD and anemia. In a cluster survey of children 12-59 months of age (n = 291) in Yaoundé and Douala, we assessed hemoglobin (Hb), malaria infection, and plasma indicators of inflammation and micronutrient status. Hb S was detected by HPLC, and α⁺thalassemia (3.7 kb deletions) by PCR. Anemia (Hb < 110 g/L), inflammation, and malaria were present in 45%, 46%, and 8% of children. A total of 13.7% of children had HbAS, 1.6% had HbSS, and 30.6% and 3.1% had heterozygous and homozygous α⁺thalassemia. The prevalence of anemia was greater among HbAS compared to HbAA children (60.3 vs. 42.0%, p = 0.038), although mean Hb concentrations did not differ, p = 0.38). Hb and anemia prevalence did not differ among children with or without single gene deletion α⁺thalassemia. In multi-variable models, anemia was independently predicted by HbAS, HbSS, malaria, iron deficiency (ID; inflammation-adjusted ferritin <12 µg/L), higher C-reactive protein, lower plasma folate, and younger age. Elevated soluble transferrin receptor concentration (>8.3 mg/L) was associated with younger age, malaria, greater mean reticulocyte counts, inflammation, HbSS genotype, and ID. IHD are prevalent but contribute modestly to anemia among children in urban Cameroon.
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Affiliation(s)
- Reina Engle-Stone
- Department of Nutrition, University of California, Davis, CA 95616, USA; or
| | | | - Martin Nankap
- Helen Keller International, Cameroon, BP 14227 Yaoundé, Cameroon; (M.N.); (A.N.); (A.T.)
| | - Alex Ndjebayi
- Helen Keller International, Cameroon, BP 14227 Yaoundé, Cameroon; (M.N.); (A.N.); (A.T.)
| | | | - Yannick Oyono
- Centre Pasteur du Cameroun, BP 1274 Yaoundé, Cameroon;
| | - Ann Tarini
- Centre Pasteur du Cameroun, BP 1274 Yaoundé, Cameroon;
| | - Kenneth H. Brown
- Department of Nutrition, University of California, Davis, CA 95616, USA; or
- Bill & Melinda Gates Foundation, Seattle, WA 98102, USA
| | - Ralph Green
- Department of Medical Pathology and Laboratory Medicine, UC Davis Medical Center, Sacramento, CA 95817, USA;
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16
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Namaste SML, Aaron GJ, Varadhan R, Peerson JM, Suchdev PS. Methodologic approach for the Biomarkers Reflecting Inflammation and Nutritional Determinants of Anemia (BRINDA) project. Am J Clin Nutr 2017; 106:333S-347S. [PMID: 28615254 PMCID: PMC5490643 DOI: 10.3945/ajcn.116.142273] [Citation(s) in RCA: 94] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Background: The Biomarkers Reflecting Inflammation and Nutritional Determinants of Anemia (BRINDA) project is a multiagency and multicountry collaboration that was formed to improve micronutrient assessment and to better characterize anemia.Objectives: The aims of the project were to 1) identify factors associated with inflammation, 2) assess the relations between inflammation, malaria infection, and biomarkers of iron and vitamin A status and compare adjustment approaches, and 3) assess risk factors for anemia in preschool children (PSC) and women of reproductive age (WRA).Design: The BRINDA database inclusion criteria included surveys that 1) were conducted after 2004, 2) had target groups of PSC, WRA, or both, and 3) used a similar laboratory methodology for the measurement of ≥1 biomarker of iron [ferritin or soluble transferrin receptor or vitamin A status (retinol-binding protein or retinol)] and ≥1 biomarker of inflammation (α-1-acid glycoprotein or C-reactive protein). Individual data sets were standardized and merged into a BRINDA database comprising 16 nationally and regionally representative surveys from 14 countries. Collectively, the database covered all 6 WHO geographic regions and contained ∼30,000 PSC and 27,000 WRA. Data were analyzed individually and combined with the use of a meta-analysis.Results: The methods that were used to standardize the BRINDA database and the analytic approaches used to address the project's research questions are presented in this article. Three approaches to adjust micronutrient biomarker concentrations in the presence of inflammation and malaria infection are presented, along with an anemia conceptual framework that guided the BRINDA project's anemia analyses.Conclusions: The BRINDA project refines approaches to interpret iron and vitamin A biomarker values in settings of inflammation and malaria infection and suggests the use of a new regression approach as well as proposes an anemia framework to which real-world data can be applied. Findings can inform guidelines and strategies to prevent and control micronutrient deficiencies and anemia globally.
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Affiliation(s)
- Sorrel ML Namaste
- Strengthening Partnerships, Results, and Innovations in Nutrition Globally, Arlington, VA;,Helen Keller International, Washington, DC
| | - Grant J Aaron
- Global Alliance for Improved Nutrition, Geneva, Switzerland
| | - Ravi Varadhan
- Department of Oncology, Johns Hopkins University, Baltimore, MD
| | - Janet M Peerson
- Department of Nutrition, University of California, Davis, Davis, CA
| | - Parminder S Suchdev
- Nutrition Branch, CDC, Atlanta, GA; and,Department of Pediatrics and Global Health, Emory University, Atlanta, GA
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17
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Engle-Stone R, Nankap M, Ndjebayi AO, Allen LH, Shahab-Ferdows S, Hampel D, Killilea DW, Gimou MM, Houghton LA, Friedman A, Tarini A, Stamm RA, Brown KH. Iron, Zinc, Folate, and Vitamin B-12 Status Increased among Women and Children in Yaoundé and Douala, Cameroon, 1 Year after Introducing Fortified Wheat Flour. J Nutr 2017; 147:1426-1436. [PMID: 28592513 PMCID: PMC5483962 DOI: 10.3945/jn.116.245076] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Revised: 01/31/2017] [Accepted: 05/03/2017] [Indexed: 01/21/2023] Open
Abstract
Background: Few data are available on the effectiveness of large-scale food fortification programs.Objective: We assessed the impact of mandatory wheat flour fortification on micronutrient status in Yaoundé and Douala, Cameroon.Methods: We conducted representative surveys 2 y before and 1 y after the introduction of fortified wheat flour. In each survey, 10 households were selected within each of the same 30 clusters (n = ∼300 households). Indicators of inflammation, malaria, anemia, and micronutrient status [plasma ferritin, soluble transferrin receptor (sTfR), zinc, folate, and vitamin B-12] were assessed among women aged 15-49 y and children 12-59 mo of age.Results: Wheat flour was consumed in the past 7 d by ≥90% of participants. Postfortification, mean total iron and zinc concentrations of flour samples were 46.2 and 73.6 mg/kg (target added amounts were 60 and 95 mg/kg, respectively). Maternal anemia prevalence was significantly lower postfortification (46.7% compared with 39.1%; adjusted P = 0.01), but mean hemoglobin concentrations and child anemia prevalence did not differ. For both women and children postfortification, mean plasma concentrations were greater for ferritin and lower for sTfR after adjustments for potential confounders. Mean plasma zinc concentrations were greater postfortification and the prevalence of low plasma zinc concentration in women after fortification (21%) was lower than before fortification (39%, P < 0.001); likewise in children, the prevalence postfortification (28%) was lower than prefortification (47%, P < 0.001). Mean plasma total folate concentrations were ∼250% greater postfortification among women (47 compared with 15 nmol/L) and children (56 compared with 20 nmol/L), and the prevalence of low plasma folate values was <1% after fortification in both population subgroups. In a nonrepresentative subset of plasma samples, folic acid was detected in 77% of women (73% of those fasting) and 93% of children. Mean plasma and breast-milk vitamin B-12 concentrations were >50% greater postfortification.Conclusion: Although the pre-post survey design limits causal inference, iron, zinc, folate, and vitamin B-12 status increased among women and children in urban Cameroon after mandatory wheat flour fortification.
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Affiliation(s)
- Reina Engle-Stone
- Department of Nutrition, University of California, Davis, Davis, CA;
| | | | | | - Lindsay H Allen
- Department of Nutrition, University of California, Davis, Davis, CA
- USDA, Agricultural Research Service Western Human Nutrition Research Center, Davis, CA
| | - Setareh Shahab-Ferdows
- Department of Nutrition, University of California, Davis, Davis, CA
- USDA, Agricultural Research Service Western Human Nutrition Research Center, Davis, CA
| | - Daniela Hampel
- Department of Nutrition, University of California, Davis, Davis, CA
- USDA, Agricultural Research Service Western Human Nutrition Research Center, Davis, CA
| | - David W Killilea
- Nutrition and Metabolism Center, Children's Hospital Oakland Research Institute, Oakland, CA
| | | | | | | | - Ann Tarini
- Helen Keller International, New York, NY
| | | | - Kenneth H Brown
- Department of Nutrition, University of California, Davis, Davis, CA
- Bill & Melinda Gates Foundation, Seattle, WA
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18
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Stoltzfus RJ, Klemm R. Research, policy, and programmatic considerations from the Biomarkers Reflecting Inflammation and Nutritional Determinants of Anemia (BRINDA) project. Am J Clin Nutr 2017; 106:428S-434S. [PMID: 28615252 PMCID: PMC5490649 DOI: 10.3945/ajcn.116.142372] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The Biomarkers Reflecting Inflammation and Nutritional Determinants of Anemia (BRINDA) project sought to inform the interpretation of iron and vitamin A biomarkers (ferritin, serum transferrin receptor, and retinol binding protein) in settings of prevalent inflammation as well as the prevention of and control strategies to address anemia. Our purpose is to comment on the contributions of the BRINDA to advance global knowledge with regard to iron and vitamin A status assessment in women and preschool children and to analyze the findings in terms of their rigor and usefulness for global nutrition research and programs. BRINDA investigators found that the acute-phase response is so prevalent that it must be assessed in surveys of iron and vitamin A status for valid interpretation of micronutrient biomarkers. Furthermore, they found that C-reactive protein and α-1-acid glycoprotein provide important and different information about these responses and that common survey variables cannot replace the information they provide. Developing a method for adjusting micronutrient biomarkers for the independent influence of inflammation is challenging and complex, and BRINDA has brought greater clarity to this challenge through the use of large and diverse data sets. When comparing approaches, the regression methods appear to perform best when sample sizes are sufficient and adequate statistical capacity is available. Further correction for malaria does not appear to materially alter regression-adjusted prevalence estimates. We suggest that researchers present both adjusted and unadjusted values for the micronutrient biomarkers. BRINDA findings confirm that iron deficiency is a common and consistent risk factor for anemia globally and that anemia control must combine iron interventions with control of infection and inflammation. Anemia control strategies must be informed by local data. By applying the knowledge in these studies, researchers, program planners, and evaluators working in populations with prevalent inflammation can use and interpret biomarkers with more confidence, tempered with necessary caution.
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Affiliation(s)
| | - Rolf Klemm
- Helen Keller International, New York, NY
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19
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Larson LM, Namaste SML, Williams AM, Engle-Stone R, Addo OY, Suchdev PS, Wirth JP, Temple V, Serdula M, Northrop-Clewes CA. Adjusting retinol-binding protein concentrations for inflammation: Biomarkers Reflecting Inflammation and Nutritional Determinants of Anemia (BRINDA) project. Am J Clin Nutr 2017; 106:390S-401S. [PMID: 28615251 PMCID: PMC5490644 DOI: 10.3945/ajcn.116.142166] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Background: The accurate estimation of the prevalence of vitamin A deficiency (VAD) is important in planning and implementing interventions. Retinol-binding protein (RBP) is often used in population surveys to measure vitamin A status, but its interpretation is challenging in settings where inflammation is common because RBP concentrations decrease during the acute-phase response.Objectives: We aimed to assess the relation between RBP concentrations and inflammation and malaria in preschool children (PSC) (age range: 6-59 mo) and women of reproductive age (WRA) (age range: 15-49 y) and to investigate adjustment algorithms to account for these effects.Design: Cross-sectional data from 8 surveys for PSC (n = 8803) and 4 surveys for WRA (n = 4191) from the Biomarkers Reflecting Inflammation and Nutritional Determinants of Anemia (BRINDA) project were analyzed individually and combined with the use of a meta-analysis. Several approaches were explored to adjust RBP concentrations in PSC in inflammation and malaria settings as follows: 1) the exclusion of subjects with C-reactive protein (CRP) concentrations >5 mg/L or α-1-acid glycoprotein (AGP) concentrations >1 g/L, 2) the application of arithmetic correction factors, and 3) the use of a regression correction approach. The impact of adjustment on the estimated prevalence of VAD (defined as <0.7 μmol/L) was examined in PSC.Results: The relation between estimated VAD and CRP and AGP deciles followed a linear pattern in PSC. In women, the correlations between RBP and CRP and AGP were too weak to justify adjustments for inflammation. Depending on the approach used to adjust for inflammation (CRP+AGP), the estimated prevalence of VAD decreased by a median of 11-18 percentage points in PSC compared with unadjusted values. There was no added effect of adjusting for malaria on the estimated VAD after adjusting for CRP and AGP.Conclusions: The use of regression correction (derived from internal data), which accounts for the severity of inflammation, to estimate the prevalence of VAD in PSC in regions with inflammation and malaria is supported by the analysis of the BRINDA data. These findings contribute to the evidence on adjusting for inflammation when estimating VAD with the use of RBP.
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Affiliation(s)
- Leila M Larson
- Nutrition and Health Sciences Program, Laney Graduate School, and
| | - Sorrel ML Namaste
- Strengthening Partnerships, Results, and Innovations in Nutrition Globally, Arlington, VA;,Helen Keller International, Washington DC
| | - Anne M Williams
- Rollins School of Public Health, Emory University, Atlanta, GA
| | | | - O Yaw Addo
- Rollins School of Public Health, Emory University, Atlanta, GA
| | - Parminder S Suchdev
- Nutrition and Health Sciences Program, Laney Graduate School, and,Rollins School of Public Health, Emory University, Atlanta, GA;,Nutrition Branch, CDC, Atlanta, GA
| | | | - Victor Temple
- School of Medicine and Health Sciences, University of Papua New Guinea, Port Moresby, Papua New Guinea; and
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20
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Vitamin A Status of Women and Children in Yaoundé and Douala, Cameroon, is Unchanged One Year after Initiation of a National Vitamin A Oil Fortification Program. Nutrients 2017; 9:nu9050522. [PMID: 28531099 PMCID: PMC5452252 DOI: 10.3390/nu9050522] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2017] [Revised: 05/06/2017] [Accepted: 05/16/2017] [Indexed: 11/17/2022] Open
Abstract
Vitamin A (VA) fortification of cooking oil is considered a cost-effective strategy for increasing VA status, but few large-scale programs have been evaluated. We conducted representative surveys in Yaoundé and Douala, Cameroon, 2 years before and 1 year after the introduction of a mandatory national program to fortify cooking oil with VA. In each survey, 10 different households were selected within each of the same 30 clusters (n = ~300). Malaria infection and plasma indicators of inflammation and VA (retinol-binding protein, pRBP) status were assessed among women aged 15-49 years and children aged 12-59 months, and casual breast milk samples were collected for VA and fat measurements. Refined oil intake was measured by a food frequency questionnaire, and VA was measured in household oil samples post-fortification. Pre-fortification, low inflammation-adjusted pRBP was common among children (33% <0.83 µmol/L), but not women (2% <0.78 µmol/L). Refined cooking oil was consumed by >80% of participants in the past week. Post-fortification, only 44% of oil samples were fortified, but fortified samples contained VA concentrations close to the target values. Controlling for age, inflammation, and other covariates, there was no difference in the mean pRBP, mean breast milk VA, prevalence of low pRBP, or prevalence of low milk VA between the pre- and post-fortification surveys. The frequency of refined oil intake was not associated with VA status indicators post-fortification. In sum, after a year of cooking oil fortification with VA, we did not detect evidence of increased plasma RBP or milk VA among urban women and preschool children, possibly because less than half of the refined oil was fortified. The enforcement of norms should be strengthened, and the program should be evaluated in other regions where the prevalence of VA deficiency was greater pre-fortification.
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Wessells KR, Ouédraogo CT, Young RR, Faye MT, Brito A, Hess SY. Micronutrient Status among Pregnant Women in Zinder, Niger and Risk Factors Associated with Deficiency. Nutrients 2017; 9:E430. [PMID: 28445440 PMCID: PMC5452160 DOI: 10.3390/nu9050430] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2017] [Revised: 04/17/2017] [Accepted: 04/20/2017] [Indexed: 12/25/2022] Open
Abstract
Anemia and micronutrient (MN) deficiencies in pregnant women are associated with adverse pregnancy outcomes. In Niger, 58.6% of pregnant women are anemic; however, MN statuses are unknown. The study objectives were to estimate the prevalence of MN deficiencies among pregnant women in Zinder, Niger and explore associated risk factors. Pregnant women living in randomly selected rural villages (n = 88) were included. Capillary and venous blood samples (n = 770) were analyzed for hemoglobin (Hb) and plasma ferritin, soluble transferrin receptor (sTfR), zinc (pZn), retinol binding protein (RBP), folate and vitamin B12. C-reactive protein and alpha-1-acid glycoprotein were measured to adjust for inflammation. The prevalence of MN deficiencies in pregnant woman was high, indicative of a severe public health problem. Prevalence of iron deficiency was 20.7% and 35.7%, by ferritin (<15 µg/L) and sTfR (>8.3 mg/L), respectively. In total, 40.7% of women had low pZn (<50 µg/dL), 79.7% had marginal RBP (<1.32 µmol/L), 44.3% of women had low folate (<10 nmol/L) and 34.8% had low B12 concentrations (<148 pmol/L). Common risk factors associated with MN status included gravidity, mid-upper-arm circumference, geophagy, malaria, and result of the woman's last pregnancy. Interventions to promote the strengthening of antenatal care, and access and adherence to nutrition and health interventions are critical among pregnant women in this population.
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Affiliation(s)
- K Ryan Wessells
- Program in International and Community Nutrition, Department of Nutrition, University of California, Davis, CA 95616, USA.
| | - Césaire T Ouédraogo
- Program in International and Community Nutrition, Department of Nutrition, University of California, Davis, CA 95616, USA.
| | - Rebecca R Young
- Program in International and Community Nutrition, Department of Nutrition, University of California, Davis, CA 95616, USA.
| | | | - Alex Brito
- USDA, ARS, Western Human Nutrition Research Center, Davis, CA 95616, USA.
| | - Sonja Y Hess
- Program in International and Community Nutrition, Department of Nutrition, University of California, Davis, CA 95616, USA.
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Abbeddou S, Yakes Jimenez E, Somé JW, Ouédraogo JB, Brown KH, Hess SY. Small-quantity lipid-based nutrient supplements containing different amounts of zinc along with diarrhea and malaria treatment increase iron and vitamin A status and reduce anemia prevalence, but do not affect zinc status in young Burkinabe children: a cluster-randomized trial. BMC Pediatr 2017; 17:46. [PMID: 28152989 PMCID: PMC5288861 DOI: 10.1186/s12887-016-0765-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 12/21/2016] [Indexed: 12/14/2022] Open
Abstract
Background We assessed the effects of providing a package of interventions including small-quantity lipid-based nutrient supplements (SQ-LNS) containing 0, 5 or 10 mg zinc and illness treatment to Burkinabe children from 9 to 18 months of age, on biomarkers of zinc, iron and vitamin A status at 18 months and compared with a non-intervention cohort (NIC). Methods Using a two-stage cluster randomized trial design, communities were randomly assigned to the intervention cohort (IC) or NIC, and extended family compounds within the IC were randomly assigned to different treatment groups. IC children (n = 2435) were provided with 20 g SQ-LNS/d containing 0, 5 or 10 mg zinc, 6 mg of iron and 400 μg of vitamin A along with malaria and diarrhea treatment. NIC children (n = 785) did not receive the intervention package. At 9 and 18 months, hemoglobin (Hb), zinc, iron and vitamin A status were assessed in a sub-group (n = 404). Plasma concentrations of zinc (pZC), ferritin (pF), soluble transferrin receptor (sTfR) and retinol-binding protein (RBP) were adjusted for inflammation. Results At baseline, 35% of children had low adjusted pZC (<65 μg/dL), 93% were anemic (Hb <110 g/L), 25% had low adjusted pF (<12 μg/L), 90% had high adjusted sTfR (>8.3 mg/L) and 47% had low adjusted RBP (<0.94 μmol/L), with no group-wise differences. Compared with the NIC, at 18 months IC children had significantly lower anemia prevalence (74 vs. 92%, p = 0.001) and lower iron deficiency prevalence (13% vs. 32% low adjusted pF and 41% vs. 71% high adjusted sTfR, p < 0.001), but no difference in pZC. Mean adjusted RBP was greater at 18 months in IC vs. NIC (0.94 μmol/L vs. 0.86 μmol/L, p = 0.015), but the prevalence of low RBP remained high in both cohorts. Within the IC, different amounts of zinc had no effect on the prevalence of low pZC or indicators of vitamin A deficiency, whereas children who received SQ-LNS with 10 mg zinc had a significantly lower mean pF at 18 months compared to children who received SQ-LNS with 5 mg zinc (p = 0.034). Conclusions SQ-LNS regardless of zinc amount and source provided along with illness treatment improved indicators of iron and vitamin A status, but not pZC. Trial registration NCT00944281 (July 21, 2009).
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Affiliation(s)
- Souheila Abbeddou
- Department of Nutrition, Program in International and Community Nutrition, University of California, One Shields Avenue, Davis, CA, 95616, USA
| | - Elizabeth Yakes Jimenez
- Center for Education Policy Research, University of New Mexico, Albuquerque, NM, USA.,Pacific Institute for Research and Evaluation, Albuquerque, NM, USA
| | - Jérome W Somé
- Department of Nutrition, Program in International and Community Nutrition, University of California, One Shields Avenue, Davis, CA, 95616, USA.,Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso
| | | | - Kenneth H Brown
- Department of Nutrition, Program in International and Community Nutrition, University of California, One Shields Avenue, Davis, CA, 95616, USA.,Nutrition and Global Development, Bill & Melinda Gates Foundation, Seattle, WA, USA
| | - Sonja Y Hess
- Department of Nutrition, Program in International and Community Nutrition, University of California, One Shields Avenue, Davis, CA, 95616, USA.
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Abizari AR, Azupogo F, Brouwer ID. Subclinical inflammation influences the association between vitamin A- and iron status among schoolchildren in Ghana. PLoS One 2017; 12:e0170747. [PMID: 28152069 PMCID: PMC5289472 DOI: 10.1371/journal.pone.0170747] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2016] [Accepted: 01/10/2017] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND AND OBJECTIVE In resource-poor settings, micronutrient deficiencies such as vitamin A deficiency may co-exist with iron-deficiency. In this study we assessed the iron and vitamin A status of schoolchildren and the association between vitamin A and iron status. METHODS A cross-sectional design using the baseline data of a dietary intervention trial conducted among randomly selected 5-12 years old schoolchildren (n = 224) from 2 rural schools in northern Ghana. Hemoglobin (Hb), serum ferritin (SF) and serum transferrin receptor (sTfR) concentrations were used as measures of iron status. Retinol binding protein (RBP) was used as a measure of vitamin A status. Subclinical inflammation (SCI) was measured using C-reactive protein (CRP) and α1-acid glycoprotein (AGP) concentrations. We examined the cross-sectional association between vitamin A and iron status biomarkers with multiple linear regressions. RESULTS The proportions of schoolchildren with anemia (WHO criteria), iron-deficiency (ID, SF <15μg/l and/or sTfR >8.5mg/l) and iron-deficiency anemia (IDA, concurrent anemia and ID) were 63.8%, 68.3% and 46.4% respectively. Low or marginal vitamin A status (0.70 μmol/l ≤ RBP < 1.05μmol/l) was present in 48.2% while 37.5% of the schoolchildren had vitamin A deficiency (VAD, RBP <0.70 μmol/l). The prevalence of SCI as well as concurrent VAD and ID were 48.7% and 25% respectively. RBP was associated with Hb (β = 7.2, P = 0.05) but not SF (β = 20.7, P = 0.33) and sTfR concentration (β = 12.0, P = 0.63). In the presence of SCI, RBP was not associated with hemoglobin status but a significant positive association was observed among children without SCI. CONCLUSIONS The study shows that RBP is significantly associated with Hb concentration but not with SF and sTfR. The observed relationship between RBP and Hb is only significant in the absence of SCI.
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Affiliation(s)
- Abdul-Razak Abizari
- Department of Community Nutrition, School of Allied Health Sciences, University for Development Studies, Tamale, Ghana
| | - Fusta Azupogo
- Department of Family and Consumer Science, Faculty of Agriculture, University for Development Studies, Tamale, Ghana
| | - Inge D. Brouwer
- Division of Human Nutrition, Wageningen University, Wageningen, The Netherlands
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Larson LM, Addo OY, Sandalinas F, Faigao K, Kupka R, Flores-Ayala R, Suchdev PS. Accounting for the influence of inflammation on retinol-binding protein in a population survey of Liberian preschool-age children. MATERNAL AND CHILD NUTRITION 2016; 13. [PMID: 26842430 DOI: 10.1111/mcn.12298] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 12/30/2015] [Accepted: 12/31/2015] [Indexed: 11/30/2022]
Abstract
Vitamin A deficiency (VAD) is an important contributor to child morbidity and mortality. The prevalence of VAD, measured by retinol-binding protein (RBP) or retinol, is overestimated in populations with a high prevalence of inflammation. We aimed to quantify and adjust for the effect of inflammation on VAD prevalence in a nationally representative survey of Liberian children 6 to 35 months of age. We compared five approaches to adjust RBP for inflammation and estimate VAD prevalence (defined as RBP < 0.7 µmol/L): (1) ignoring inflammation; (2) excluding individuals with inflammation (C-reactive protein (CRP) >5 mg/L or alpha1-acid glycoprotein (AGP) >1 g/)L; (3) multiplying each individual's RBP by an internal correction factor; (4) by an external correction factor; and (5) using regression (corrected RBP = exp(InRBP - β1 (lnCRPobs -lnCRPref ) - β2 (lnAGPobs -lnAGPref )). Corrected RBP was based on a regression model where reference lnCRP and lnAGP were set to the maximum of the lowest decile. The unadjusted prevalence of VAD was 24.7%. Children with elevated CRP and/or AGP had significantly lower RBP concentrations than their apparently healthy peers (geometric mean RBP 0.79 µmol/L (95% CI: 0.76, 0.82) vs. 0.95 µmol/L (95% CI: 0.92, 0.97), P < 0.001). Using approaches 2-5 resulted in a prevalence of VAD of 11.6%, 14.3%, 13.5% and 7.3%, respectively. Depending on the approach, the VAD prevalence is reduced 10-17 percentage points when inflammation is taken into account. Further quantification of the influence of inflammation on biomarkers of vitamin A status from other national surveys is needed to compare and recommend the preferred adjustment approach across populations.
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Affiliation(s)
- Leila Margaret Larson
- Nutrition and Health Sciences Program, Laney Graduate School, Emory University, Atlanta, Georgia, USA
| | - O Yaw Addo
- Rollins School of Public Health, Emory University, Atlanta, Georgia, USA
| | - Fanny Sandalinas
- UNICEF Regional Office for West and Central Africa, Dakar, Senegal
| | | | - Roland Kupka
- UNICEF Regional Office for West and Central Africa, Dakar, Senegal
| | - Rafael Flores-Ayala
- Rollins School of Public Health, Emory University, Atlanta, Georgia, USA.,Nutrition Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Parminder S Suchdev
- Nutrition and Health Sciences Program, Laney Graduate School, Emory University, Atlanta, Georgia, USA.,Rollins School of Public Health, Emory University, Atlanta, Georgia, USA.,Nutrition Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
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