Comparability of Inflammation-Adjusted Vitamin A Deficiency Estimates and Variance in Retinol Explained by C-Reactive Protein and α1-Acid Glycoprotein during Low and High Malaria Transmission Seasons in Rural Zambian Children

Barffour, Maxwell A.; Schulze, Kerry; Coles, Christian; Chileshe, Justin; Kalungwana, Ng’andwe; Arguello, Margia; Siamusantu, Ward; Moss, William J.; West, Keith P.; Palmer, Amanda

doi:10.4269/ajtmh.17-0130

Cited by 11 publications

(10 citation statements)

References 35 publications

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“…This could have resulted because of collinearity as the bivariate analyses showed negative association for both inflammatory markers. Other studies have also reported similar findings [ 31 , 38 ], and this has a consequence for the inflammation adjustment methods that are used. It would appear that to accurately adjust for SR, only CRP should be accounted for as opposed to both CRP and AGP.…”

Section: Discussionsupporting

confidence: 68%

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

et al. 2021

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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.

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Section: Discussionsupporting

confidence: 68%

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

et al. 2021

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“…Furthermore, previous episodes of malaria can affect subject’s VA status, as during the reproductive cycle and metabolism of the Plamosdium malaria the host’s liver is affected. In this sense, frequent episodes of malaria through the life course may impair adequate retinol stores as well as raise concentrations of acute-phase proteins, such as CRP ( 46 ) . Nevertheless, neither the history of malaria nor the CRP concentration was associated with the VA status in pregnancy in this study.…”

Section: Discussionmentioning

confidence: 99%

Predictors of vitamin A status among pregnant women in Western Brazilian Amazon

et al. 2018

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Determining the predictors of serum retinol at mid-pregnancy is relevant for planning interventions aimed at improving vitamin A status of pregnant women and their offspring. This prospective study assessed predictors of serum retinol at the beginning of the third trimester of pregnancy. We enrolled 442 pregnant women living in the urban area of Cruzeiro do Sul, Western Brazilian Amazon. Demographic, socio-economic, environmental and clinical characteristics as well as obstetric history, anthropometric, dietary and biochemical data, including serum retinol, were gathered between 16 and 20 gestational weeks. Serum retinol also measured at the beginning of the third trimester of pregnancy (approximately 28 gestational weeks) was the outcome of interest. Multiple linear regression models were used to evaluate associations with the outcome. Overall, the following variables explained serum retinol at the beginning of the third trimester of pregnancy in the adjusted model (R2 = 11·1 %): seasonality (winter season – November to April; β=0·134; 95 % CI 0·063, 0·206), weekly consumption of Amazonian fruits (β=0·087; 95 % CI 0·012, 0·162) and retinol concentrations between 16 and 20 gestational weeks (β=0·045; 95 % CI 0·016, 0·074) were positively associated, whereas having a smoker in the house was negatively associated (β=–0·087; 95 % CI: –0·166, –0·009). Consumption of pro-vitamin A-rich fruits by pregnant women should be encouraged. Passive smoking may play a role in decreasing vitamin A status as a proxy of smoking exposure during pregnancy.

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“…Another important difference from most other intervention studies is that we adjusted for inflammatory markers. The impact of inflammation on serum retinol concentration is quite established ( 30 , 44–46 ). Helminth, bacterial, and viral infections can trigger inflammatory mechanisms, which consequently lead to a decrease in negative acute phase proteins, such as RBP, responsible for the transportation of retinol from the liver to other body compartments ( 47 , 48 ).…”

Section: Discussionmentioning

confidence: 99%

“…Serum CRP and AGP are commonly used to adjust for the effect of inflammation on serum retinol concentrations. However, it was recently shown that in a malaria-endemic population, CRP alone explained the highest percentage of the variance in serum retinol concentrations, in addition to the observation that AGP explained little of the remaining variance ( 30 ). We thus used only CRP for inflammation adjustment as described by Palmer et al ( 30 ).…”

Section: Methodsmentioning

confidence: 99%

“…VAD was defined as serum retinol concentration <0.7 µmol/L, after adjustment for CRP ( 31 ). Moderate inflammation was defined as serum CRP >5 mg/L and ≤15 mg/L; high inflammation, serum CRP >15 mg/L ( 30 ); anemia, serum Hb <110 g/L; iron deficiency, serum ferritin concentration <30 µg/L when children with inflammation were included or <12 µg/L when children with inflammation were excluded ( 32 ); serum soluble transferrin receptor concentration >8.3 µg/mL ( 33 ); malaria infection, Plasmodium parasite count per microliter of whole blood >0; and stunting, wasting, and underweight were defined as ≤−2 z scores of WHO child growth references for height-for-age, weight-for-height, and weight-for-age, respectively ( 34 ). Feeding compliance was predefined as the ability to consume the minimum targeted amount of intervention food per day—that is, ≥100 g of eba, ≥32 g of garri, and ≥15 g of moinmoin.…”

Section: Methodsmentioning

confidence: 99%

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Daily consumption of pro-vitamin A biofortified (yellow) cassava improves serum retinol concentrations in preschool children in Nigeria: a randomized controlled trial

Afolami

Mwangi

Samuel

et al. 2021

The American Journal of Clinical Nutrition

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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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Comparability of Inflammation-Adjusted Vitamin A Deficiency Estimates and Variance in Retinol Explained by C-Reactive Protein and α1-Acid Glycoprotein during Low and High Malaria Transmission Seasons in Rural Zambian Children

Cited by 11 publications

References 35 publications

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

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

Predictors of vitamin A status among pregnant women in Western Brazilian Amazon

Daily consumption of pro-vitamin A biofortified (yellow) cassava improves serum retinol concentrations in preschool children in Nigeria: a randomized controlled trial

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