Accounting for the influence of inflammation on retinol‐binding protein in a population survey of Liberian preschool‐age children

Larson, Leila M; Addo, O Yaw; Sandalinas, Fanny; Faigao, Katherine; Kupka, Roland; Flores‐Ayala, Rafael; Suchdev, Parminder S.

doi:10.1111/mcn.12298

Cited by 29 publications

(37 citation statements)

References 23 publications

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“…These inflammation markers will assist in interpreting low ROH values [91]. Various adjustment approaches exist [92,93], and there is a growing consensus that VAD should only be estimated once ROH or RBP are adjusted using both C-reactive protein and alpha 1-acid glycoprotein. Despite these obstacles, micronutrient surveys have been successfully undertaken in countries with poor road infrastructure, limited electricity networks, and only basic laboratory capacity.…”

Section: Discussionmentioning

confidence: 99%

Vitamin A Supplementation Programs and Country-Level Evidence of Vitamin A Deficiency

Wirth¹,

Petry²,

et al. 2017

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Vitamin A supplementation (VAS) programs targeted at children aged 6–59 months are implemented in many countries. By improving immune function, vitamin A (VA) reduces mortality associated with measles, diarrhea, and other illnesses. There is currently a debate regarding the relevance of VAS, but amidst the debate, researchers acknowledge that the majority of nationally-representative data on VA status is outdated. To address this data gap and contribute to the debate, we examined data from 82 countries implementing VAS programs, identified other VA programs, and assessed the recentness of national VA deficiency (VAD) data. We found that two-thirds of the countries explored either have no VAD data or data that were >10 years old (i.e., measured before 2006), which included twenty countries with VAS coverage ≥70%. Fifty-one VAS programs were implemented in parallel with at least one other VA intervention, and of these, 27 countries either had no VAD data or data collected in 2005 or earlier. To fill these gaps in VAD data, countries implementing VAS and other VA interventions should measure VA status in children at least every 10 years. At the same time, the coverage of VA interventions can also be measured. We identified three countries that have scaled down VAS, but given the lack of VA deficiency data, this would be a premature undertaking in most countries without appropriate status assessment. While the global debate about VAS is important, more attention should be directed towards individual countries where programmatic decisions are made.

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Section: Discussionmentioning

confidence: 99%

Vitamin A Supplementation Programs and Country-Level Evidence of Vitamin A Deficiency

Wirth¹,

Petry²,

et al. 2017

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“…A multivariate, linear regression approach for adjusting IIH has recently been proposed. 16,35 The advantage of this approach is that it estimates context-specific adjustment factors, based on observed associations between specific nutritional biomarkers and the acute phase reactants, as opposed to using predefined cut-offs for inflammation. However, this approach has several limitations.…”

Section: Discussionmentioning

confidence: 99%

“…To mitigate the problem of overadjustment, Larson et al suggested that adjustment factors be applied to individuals at or above the first decile of the lognormalized AGP and CRP concentrations, as opposed to every individual. 16 Had we adopted this approach, we would have adjusted the retinol concentrations in over 90% of our study population. Such a procedure, which would imply that nearly all children have some degree of IIH, may be unjustifiable, even in regions with a high burden of infection.…”

Section: Discussionmentioning

confidence: 99%

“…Furthermore, the practice of using both AGP and CRP to control for IIH is becoming conventional. [15][16][17] This approach, originally proposed by Thurnham et al, 17 is based on two important assumptions, namely 1) the inflammation-associated reduction in retinol coincides with the sequential rise in both CRP (during the early phase) and AGP (during the late phase), and 2) the early and late phases of inflammation likely affect retinol concentrations differently. Thus, adjustment for both APPs may be necessary to fully account for IIH.…”

Section: Introductionmentioning

confidence: 99%

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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

Barffour

Schulze

Coles

et al. 2018

The American Journal of Tropical Medicine and Hygiene

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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, = 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; < 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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“…45 This risk can be assessed by measuring dietary VA intakes or biological indicators of VA stores, which is discussed further in paper 3 of this series. Excessive VA intakes are generally defined by consumption greater than the tolerable upper intake level (UL).…”

Section: Safety Of Vitamin a Programsmentioning

confidence: 99%

A Changing Landscape for Vitamin A Programs

et al. 2016

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Where intervention overlap exists, further effort is needed to monitor VA intakes, ensuring that targeted groups are consuming adequate amounts but not exceeding the tolerable upper intake level. Vitamin A status data will also be critical for navigating the changing landscape of VA programs. Data from these monitoring efforts will help to guide decisions on the optimal mix, targeting, and exposure to VA interventions to maximize public health benefit while minimizing any potential risk.

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Accounting for the influence of inflammation on retinol‐binding protein in a population survey of Liberian preschool‐age children

Cited by 29 publications

References 23 publications

Vitamin A Supplementation Programs and Country-Level Evidence of Vitamin A Deficiency

Vitamin A Supplementation Programs and Country-Level Evidence of Vitamin A Deficiency

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

A Changing Landscape for Vitamin A Programs

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