scholarly journals Approaches to Assess Vitamin A Status in Settings of Inflammation: Biomarkers Reflecting Inflammation and Nutritional Determinants of Anemia (BRINDA) Project

Nutrients ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 1100 ◽  
Author(s):  
Leila Larson ◽  
Junjie Guo ◽  
Anne Williams ◽  
Melissa Young ◽  
Sanober Ismaily ◽  
...  
Keyword(s):  
Vitamin A ◽  
Vitamin A Deficiency ◽  
Full Range ◽  
Preschool Age ◽  
Reproductive Age ◽  
Retinol Binding Protein ◽  
School Age Children ◽  
Accurate Estimation ◽  
Serum Retinol ◽  
Regression Approach

The accurate estimation of vitamin A deficiency (VAD) is critical to informing programmatic and policy decisions that could have important public health implications. However, serum retinol and retinol binding protein (RBP) concentrations, two biomarkers often used to estimate VAD, are temporarily altered during the acute phase response, potentially overestimating the prevalence of VAD in populations with high levels of inflammation. In 22 nationally-representative surveys, we examined (1) the association between C-reactive protein (CRP) or α1-acid glycoprotein (AGP) and retinol or RBP, and (2) how different adjustment approaches for correcting for inflammation compare with one another. In preschool age children (PSC) and school age children (SAC), the association between inflammation and retinol and RBP was largely statistically significant; using the regression approach, adjustments for inflammation decreased the estimated prevalence of VAD compared to unadjusted VAD (range: −22.1 to −6.0 percentage points). In non-pregnant women of reproductive age (WRA), the association between inflammation and vitamin A biomarkers was inconsistent, precluding adjustments for inflammation. The burden of VAD can be overestimated if inflammation is not accounted for, and the regression approach provides a method for adjusting retinol and RBP for inflammation across the full range of concentrations in PSC and SAC.

scholarly journals Use of the retinol-binding protein : transthyretin ratio for assessment of vitamin A status during the acute-phase response

2000 ◽  
Vol 83 (5) ◽  
pp. 513-520 ◽  
Author(s):  
Suzanne M. Filteau ◽  
Juana F. Willumsen ◽  
Keith Sullivan ◽  
Karin Simmank ◽  
Mary Gamble
Keyword(s):  
Vitamin A ◽  
Sensitivity And Specificity ◽  
Assessment Tool ◽  
Binding Protein ◽  
Vitamin A Deficiency ◽  
Retinol Binding Protein ◽  
Serum Retinol ◽  
Vitamin A Status ◽  
Plasma Retinol

The ratio plasma retinol-binding protein (RBP) : transthyretin (TTR) has been proposed as a means to improve the assessment of vitamin A status of individuals with concurrent infection or inflammation. We have measured RBP and TTR in stored sera from South African children who had accidentally ingested kerosene. Samples were collected from these children in hospital when suffering acute inflammation and respiratory distress, and from them and neighbourhood control children 3 months later. Vitamin A status was defined by modified relative dose response (MRDR) tests of liver retinol stores at 3 months and by serum retinol concentration both when children were ill and when they were well. Illness was defined as either being in hospital or, at follow-up, as having a raised plasma α1-acid glycoprotein (AGP) level. The RBP : TTR value was significantly decreased by both illness and low liver retinol stores. When the effects on RBP : TTR of illness and vitamin A stores were considered together for the 3-month follow-up samples, only vitamin A status significantly decreased the value. We calculated sensitivity and specificity of the RBP : TTR ratio against established measures of vitamin A status using a cut-off value of 0·3 for RBP : TTR and standard cut-off values for MRDR (0·06) and plasma retinol (0·7 μmol/l). Compared with MRDR, RBP : TTR had sensitivities of 76 % and 43 % and specificities of 22 % and 81 % to detect vitamin A deficiency in hospitalized and well children respectively. Compared with plasma retinol, sensitivities were 88 % and 44 % and specificities were 55 % and 64 % in hospitalized and well children respectively. Only for the case of clinically well children with biochemical evidence of subclinical inflammation did sensitivity (62 % and 100 % against MRDR and plasma retinol respectively) and specificity (100 % and 60 % against MRDR and retinol) approach useful levels for an assessment tool. Overall, although a trend supporting the theory behind the use of the RBP : TTR for assessment of vitamin A status in infection was observed in the current study, the ratio did not provide adequate sensitivity and specificity to be a useful assessment tool.

scholarly journals Vitamin A deficiency in Bangladesh: a review and recommendations for improvement

1999 ◽  
Vol 2 (1) ◽  
pp. 1-14 ◽  
Author(s):  
Faruk Ahmed
Keyword(s):  
Vitamin A ◽  
Nutrition Education ◽  
Night Blindness ◽  
Vitamin A Deficiency ◽  
School Age Children ◽  
Serum Retinol ◽  
Population Groups ◽  
Vitamin A Status ◽  
Subclinical Vitamin

AbstractObjective:This article provides a comprehensive review of the change in vitamin A status and the extent of vitamin A deficiency among different population groups in Bangladesh up to the present time. The result of experience with different strategies and interventions designed to improve vitamin A status are then reviewed, leading to a discussion of key options for action, as well as important areas for research and evaluation.Design and setting:All the available data have been examined in detail, including data from nationally representative samples and nationwide surveys, as well as small studies in different population groups. Reports on the effectiveness of different intervention programmes have been used.Results:Over the past three decades a number of studies, which include national nutrition surveys, have been carried out to investigate the prevalence of vitamin A deficiency among different population groups in Bangladesh, and they have demonstrated a significant public health problem. Studies have shown that the prevalence of severe deficiency, based on the prevalence of night blindness in preschool children, decreased from 3.6% in 1982–83 to 1.78% in 1989 and 0.6% in 1996. However, there is still a high prevalence of subclinical vitamin A deficiency, based on the biochemical assessment of serum retinol levels in preschool children, estimated mainly from hospital-based groups. Night blindness and Bitot's spot are also found to exist among school-age children and adolescents. Recent reports indicate that night blindness among rural mothers is as high as 1.4%. Only a limited number of studies, with small sample sizes, are available where serum retinol has been reported for school-age children, adolescents and pregnant women. Nevertheless, these studies confirm the presence of low levels of serum retinol and hence, the existence of subclinical vitamin A deficiency. Furthermore, the dietary intake of vitamin A in each population group has been found to be less than the Recommended Daily Allowance (RDA), indicating a significant risk of deficient intakes of vitamin A.To address the problem of vitamin A deficiency, the government of Bangladesh started the Nutritional Blindness Programme in 1973. The main activities of the programme include vitamin A capsule (VAC) supplementation to children of 6 months to 6 years old, nutrition education to increase the production and consumption of vitamin A rich foods, and training of primary health-care workers on the clinical diagnosis and treatment of vitamin A deficiency, VAC distribution and nutrition education. Since 1988, as a long-term strategy, Helen Keller International has been implementing community home gardening promotion projects. To date, the possibility that foods may be fortified with vitamin A, has not been explored as a possible approach in Bangladesh.Conclusion:Although short- to long-term prevention and control programmes are to some extent in place, to improve the situation of vitamin A deficiency, Bangladesh needs a more appropriate mix of interventions for the entire population. More operational research and evaluation are needed if a fully effective programme to alleviate the problem of vitamin A deficiency is to be developed. Finally, to achieve the goal of virtual elimination of vitamin A deficiency will require an integrated approach which brings together appropriate actions at every level, within and across the many sectors of society.

scholarly journals Efficacy of massive oral doses of retinyl palmitate and mango (Mangifera indica L.) consumption to correct an existing vitamin A deficiency in Senegalese children

1992 ◽  
Vol 68 (2) ◽  
pp. 529-540 ◽  
Author(s):  
Cécile Carlier ◽  
Michel Etchepare ◽  
Jean-François Ceccon ◽  
Marie-Sophie Mourey ◽  
Olivier Amédée-Manesme
Keyword(s):  
Vitamin A ◽  
Vitamin A Deficiency ◽  
Mangifera Indica ◽  
Retinyl Palmitate ◽  
Retinol Binding Protein ◽  
Serum Retinol ◽  
Abnormal Cytology ◽  
Normal Cytology ◽  
Oral Doses ◽  
Β Carotene

Administration of large oral doses of retinyl palmitate has become the most widely practised vitamin A deficiency prevention strategy in developing countries. We conducted a follow-up study among 220 Senegalese children aged 2–7 years suffering from moderate undernutrition to determine the efficacy of vitamin A treatment on their vitamin A status assessed by biochemical and cytological (impression cytology with transfer) methods. The first examination (T = 0 m[onth]) was carried out during April 1989, before the mango (Mangifera indica L,) harvest. The second examination (T = 2 m) was carried out 2 months after vitamin A treatment during June 1989 when ripe mangoes become widely available. Conjunctival cells of the eyes of the children with or without ocular inflammation were responsive to vitamin A administration (P < 0.01). There was a significant increase (P < 0.001) in mean serum retinol and β-carotene levels between T = 0 m and T = 2 m. Mean serum retinol-binding protein (RBP) and transthyretin (TTR) levels did not differ significantly (P > 0.05) at T = 0 m and T = 2 m. Despite the intake of vitamin A, 54% of the children who had abnormal cytology at T = 0 m remained abnormal at T = 2 m. This was due to inadequate levels of TTR and RBP, presumably due to the cereal diet eaten by the Senegalese population. Children with abnormal eye cytology had lower serum retinol levels than those with normal eyes at T = 0 m, and β-carotene values did not correlate with eye cytological abnormalities at T = 0 m. Children with normal cytology had higher serum retinol and also β-carotene levels than those with abnormal cytology after massive oral doses of vitamin A and consumption of mangoes at T = 2 m. Retinyl palmitate may, therefore, only lead to partial cytological improvement due to a lack of retinol-carrier proteins but dietary β-carotene may also be involved

Application of Retinol-Binding Protein Enzyme Immunoassay to Dried Blood Spots to Assess Vitamin A Deficiency in a Population-Based Survey: The Uganda Demographic and Health Survey 2006

2008 ◽  
Vol 29 (4) ◽  
pp. 297-305 ◽  
Author(s):  
Rhona Kezabu Baingana ◽  
Denis Kasozi Matovu ◽  
Dean Garrett
Keyword(s):  
Vitamin A ◽  
Enzyme Immunoassay ◽  
Health Survey ◽  
Vitamin A Deficiency ◽  
Population Level ◽  
Dried Blood Spots ◽  
Retinol Binding Protein ◽  
Serum Retinol ◽  
Blood Spots ◽  
Resource Poor

Background Vitamin A deficiency is a public health problem in most developing countries. The technological challenges associated with the measurement of serum retinol have limited the epidemiologic assessment of vitamin A deficiency. The combination of retinol-binding protein (RBP) enzyme immunoassay and dried blood spots offers a rapid, inexpensive, and reliable tool for the population-level assessment of vitamin A deficiency in resource-poor settings. Objective To report on the application of RBP enzyme immunoassay and dried blood spots to assess serum retinol concentrations as an indicator of vitamin A status in the Uganda Demographic and Health Survey 2006. Methods A total of 5,642 capillary blood spot samples were collected by fingerprick onto filter paper cards from women (15–49 years) and children (6–59 months) in a representative probability sample of 9,864 households between May and October 2006. The cards were dried, packed individually with desiccant, and kept at 4°C in a portable refrigerator in the field and at –20°C in the laboratory. Prior to analysis, the RBP enzyme immunoassay was optimized with the use of matched serum and dried blood spots. Results The correlation between RBP values determined by matching serum and dried blood spots was excellent ( r = 0.79, p < .00001). The prevalence of vitamin A deficiency in women (RBP < 1.24 μmol/L) and children (RBP < 0.825 μmol/L) was 19.4% and 20.4%, respectively. Conclusions The combination of RBP enzyme immunoassay and dried blood spots is a simple, reliable, and cost-effective tool for the estimation of vitamin A deficiency in population-level surveys in resource-poor settings.

scholarly journals Vitamin A deficiency and determinants of vitamin A status in Bangladeshi children and women: findings of a national survey

2016 ◽  
Vol 20 (6) ◽  
pp. 1114-1125 ◽  
Author(s):  
Sabuktagin Rahman ◽  
Ahmed Shafiqur Rahman ◽  
Nurul Alam ◽  
AM Shamsir Ahmed ◽  
Santhia Ireen ◽  
...  
Keyword(s):  
Vitamin A ◽  
Vitamin A Deficiency ◽  
Leafy Vegetables ◽  
School Age Children ◽  
Dietary Vitamin ◽  
School Age ◽  
Serum Retinol ◽  
Animal Source Foods ◽  
Animal Source ◽  
Subclinical Vitamin

AbstractObjectiveUsing data from the national micronutrients survey 2011–2012, the present study explored the status of subclinical vitamin A nutrition and the underlying determinants in the Bangladeshi population.DesignA nationwide cross-sectional study.SettingsThe survey covered 150 clusters; fifty in each of rural, urban and slum strata.SubjectsThree population groups: (i) pre-school age children (6–59 months; PSAC); (ii) school age children (6–14 years; SAC); and (iii) non-pregnant non-lactating women (15–49 years; NPNLW).ResultsNational prevalence of subclinical vitamin A deficiency was 20·5, 20·8 and 5·3 % in PSAC, SAC and NPNLW, respectively. Slum populations had higher prevalence compared with urban (PSAC: 38·1 v. 21·2 %, P<0·001; SAC: 27·1 v. 22·1 %, P=0·004; NPNLW: 6·8 v. 4·7 %, P=0·01). Dietary vitamin A met up to 27·1–46·0 % of daily needs; plant-source vitamin A constituted 73–87 % of the intakes. Multivariable regression analyses showed that higher consumption of animal foods was associated with higher retinol status in PSAC (β=0·27; P<0·001); and living in urban area was related to higher retinol status in NPNLW (β=0·08, P=0·004) and PSAC (β=0·11, P=0·04). Increased intake of leafy vegetables was associated with lower retinol status in SAC (β=−0·08, P=0·02). Vitamin A supplementation in PSAC did not significantly influence serum retinol within one year post-supplementation (P>0·05 for differences in β between <3 months v. 3–6 months, 6–9 months and 9–12 months).ConclusionsPrevalence of subclinical vitamin A deficiency was high in children in Bangladesh. Intakes of animal-source foods and leafy vegetables were associated with higher and lower retinol status, respectively. Increased food diversity through animal-source foods is required.

scholarly journals Comparison of Serum Retinol and Retinol-Binding Protein with the Modified Relative Dose-Response Test in Estimating Vitamin A Deficiency Among Ghanaian Women and Children

2020 ◽  
Vol 4 (Supplement_2) ◽  
pp. 913-913
Author(s):  
Devika Suri ◽  
James Wirth ◽  
Nicolai Petry ◽  
Fabian Rohner ◽  
Seth Adu-Afarwuah ◽  
...  
Keyword(s):  
Vitamin A ◽  
Sensitivity And Specificity ◽  
Dose Response ◽  
Roc Curve ◽  
Binding Protein ◽  
Vitamin A Deficiency ◽  
Retinol Binding Protein ◽  
Serum Retinol ◽  
Women And Children ◽  
Modified Relative Dose Response

Abstract Objectives To evaluate the sensitivity and specificity of serum retinol (SR) and retinol-binding protein (RBP) in determining vitamin A deficiency (VAD) using the modified relative dose-response (MRDR) test as the reference. Methods Subjects included a subset of women and children participating in the Ghana Micronutrient Survey 2017. VAD was determined by the following cut-offs: SR or RBP &lt; 0.7 mmol/L; MRDR ratio of 3,4-didehydroretinol to SR ³0.060. Sensitivity, specificity and the area-under-the-receiver operating characteristic (ROC) curve were calculated for unadjusted and inflammation-adjusted VAD cut-offs (based on C-reactive protein (CRP) and a1-acid-glycoprotein (AGP) for SR and RBP using the MRDR test as the reference. Results In 167 children and 178 women, inflammation (elevated CRP and/or elevated AGP) was present in 41% and 16%, respectively. Prevalence of VAD ranged, depending on the indicator used, from 7% (MRDR) to 40% (unadjusted SR) in children and 1% (RBP) to 4% (SR and MRDR) in women. Among children, sensitivity and specificity of unadjusted and adjusted SR and RBP were highly variable among the children. Highest sensitivity was achieved by unadjusted SR (80% of children with VAD correctly identified), while highest specificity was achieved by adjusted RBP (86% of children without VAD correctly identified). The best predictor of VAD in children compared with MRDR was adjusted SR, with a sensitivity of 78%, specificity of 73%, and an area under the ROC curve of 0.76. Among women, specificity was 97% for unadjusted and adjusted SR with an area under the ROC curve of 0.48; additional values could not be calculated due to lack of VAD cases. Conclusions SR and RBP were only moderately sensitive and specific for identifying VAD in children in Ghana. Low specificity—falsely identifying VAD—is especially problematic when populations are covered by one or more vitamin A interventions. Overlapping sources of preformed vitamin A can lead to hypervitaminosis, which may affect bone metabolism and growth. More accurate measures should be used in conjunction with SR and RBP for evaluating VAD especially in vulnerable populations. Funding Sources UNICEF, Canada's Ministry of Foreign Affairs, Trade and Development.

scholarly journals Re-Defining the Population-Specific Cut-Off Mark for Vitamin A Deficiency in Pre-School Children of Malawi

Nutrients ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 849
Author(s):  
Blessings H. Likoswe ◽  
Edward J. M. Joy ◽  
Fanny Sandalinas ◽  
Suzanne Filteau ◽  
Kenneth Maleta ◽  
...  
Keyword(s):  
Vitamin A ◽  
School Children ◽  
Vitamin A Deficiency ◽  
Threshold Concentration ◽  
The Body ◽  
Retinol Binding Protein ◽  
World Health ◽  
Target Tissue ◽  
Serum Retinol ◽  
Health Organization

Retinol Binding Protein (RBP) is responsible for the transport of serum retinol (SR) to target tissue in the body. Since RBP is relatively easy and cheap to measure, it is widely used in national Micronutrient Surveys (MNS) as a proxy for SR to determine vitamin A status. By regressing RBP concentration against SR concentration measured in a subset of the survey population, one can define a population-specific threshold concentration of RBP that indicates vitamin A deficiency (VAD). However, the relationship between RBP and SR concentrations is affected by various factors including inflammation. This study, therefore, aimed to re-define the population-specific cut-off for VAD by examining the influence of inflammation on RBP and SR, among pre-school children (PSC) from the 2015–16 Malawi MNS. The initial association between RBP and SR concentrations was poor, and this remained the case despite applying various methods to correct for inflammation. The World Health Organization (WHO) recommends the threshold of 0.7 µmol/L to define VAD for SR concentrations. Applying this threshold to the RBP concentrations gave a VAD prevalence of 24%, which reduced to 10% after inflammation adjustments following methods developed by the Biomarkers Reflecting Inflammation and Nutritional Determinants of Anemia (BRINDA). Further research is required to identify why SR and RBP were poorly associated in this population. Future MNS will need to account for the effect of inflammation on RBP to measure the prevalence of VAD in Malawi.

scholarly journals Effects of Inflammation on Biomarkers of Vitamin A Status among a Cohort of Bolivian Infants

Nutrients ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1240 ◽  
Author(s):  
Rachel Burke ◽  
Ralph Whitehead ◽  
Janet Figueroa ◽  
Denis Whelan ◽  
Anna Aceituno ◽  
...  
Keyword(s):  
Infant Mortality ◽  
Linear Regression ◽  
Vitamin A ◽  
Vitamin A Deficiency ◽  
Retinol Binding Protein ◽  
Molar Ratio ◽  
Serum Retinol ◽  
Serum Samples ◽  
Mortality And Morbidity ◽  
Vitamin A Status

Globally, vitamin A deficiency (VAD) affects nearly 200 million children with negative health consequences. VAD can be measured by a retinol-binding protein (RBP) and serum retinol concentrations. Their concentrations are not always present in a 1:1 molar ratio and are affected by inflammation. This study sought to quantify VAD and its impact on infant mortality and infectious morbidity during the first 18 months of life in a cohort of mother-infant dyads in El Alto, Bolivia, while accounting for the previously mentioned measurement issues. Healthy mother-infant dyads (n = 461) were enrolled from two hospitals and followed for 12 to 18 months. Three serum samples were collected (at one to two, six to eight, and 12 to 18 months of infant age) and analyzed for RBP, and a random 10% subsample was analyzed for retinol. Linear regression of RBP on retinol was used to generate RBP cut-offs equivalent to retinol <0.7 µmol/L. All measures of RBP and retinol were adjusted for inflammation, which was measured by a C-reactive protein and alpha (1)-acid glycoprotein serum concentrations using linear regression. Infant mortality and morbidity rates were calculated and compared by early VAD status at two months of age. Retinol and RBP were weakly affected by inflammation. This association varied with infant age. Estimated VAD (RBP < 0.7 µmol/L) decreased from 71.0% to 14.8% to 7.7% at two, six to eight, and 12 to 18 months of age. VAD was almost nonexistent in mothers. Early VAD was not significantly associated with infant mortality or morbidity rates. This study confirmed a relationship between inflammation and vitamin A biomarkers for some subsets of the population and suggested that the vitamin A status in early infancy improves with age and may not have significantly affected morbidity in this population of healthy infants.

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