Interpretation of vitamin A status in apparently healthy Pakistani children by using markers of subclinical infection

Paracha, Parvez I; Jamil, Abdul; Northrop-Clewes, Christine A.; Thurnham, David I.

doi:10.1093/ajcn/72.5.1164

Cited by 66 publications

(55 citation statements)

References 21 publications

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“…Similar observations by group were made in Pakistani preschoolers (23): incubating (0.2%) and early (11.0%) and late convalescence (50.7%). This is because the incubation period is very short (~48 h) and a high intensity of inflammation is required for numbers in this group to be large, whereas the late convalescence period is usually longer, especially in situations of poor nutritional status and slow recovery from disease (10).…”

Section: Discussionsupporting

confidence: 82%

Correcting for Inflammation Changes Estimates of Iron Deficiency among Rural Kenyan Preschool Children

Grant¹,

Suchdev²,

Flores‐Ayala³

et al. 2011

SciVee

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The assessment of iron status where infections are common is complicated by the effects of inflammation on iron indicators and in this study we compared approaches that adjust for this influence. Blood was collected in 680 children (aged 6-35 mo) and indicators of iron status [(hemoglobin (Hb), zinc protoporphyrin (ZP), ferritin, transferrin receptor (TfR), and TfR/ferritin index)] and subclinical inflammation [(the acute phase proteins (APP) C-reactive protein (CRP), and α-1-acid glycoprotein (AGP)] were determined. Malaria parasitemia was assessed. Subclinical inflammation was defined as CRP >5 mg/L and/or AGP>1 g/L). Four groups were defined based on APP levels: reference (normal CRP and AGP), incubation (raised CRP and normal AGP), early convalescence (raised CRP and AGP), and late convalescence (normal CRP and raised AGP). Correction factors (CF) were estimated as the ratios of geometric means of iron indicators to the reference group of those for each inflammation group. Corrected values of iron indicators within inflammation groups were obtained by multiplying values by their respective group CF. CRP correlated with AGP (r = 0.65; P < 0.001), ferritin (r = 0.38; P < 0.001), Hb (r = −0.27; P < 0.001), and ZP (r = 0.16; P < 0.001); AGP was correlated with ferritin (r = 0.39; P < 0.001), Hb (r = −0.29; P < 0.001), and ZP (r = 0.24; P < 0.001). Use of CF to adjust for inflammation increased the prevalence of ID based on ferritin < 12 µg/L by 34% (from 27 to 41%). Applying the CF HHS Public Access Author Manuscript Author ManuscriptAuthor ManuscriptAuthor Manuscript strengthened the expected relationship between Hb and ferritin (r = 0.10; P = 0.013 vs. r = 0.20; P < 0.001, before and after adjustment, respectively). Although the use of CF to adjust for inflammation appears indicated, further work is needed to confirm that this approach improves the accuracy of assessment of ID.

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Section: Discussionsupporting

confidence: 82%

Correcting for Inflammation Changes Estimates of Iron Deficiency among Rural Kenyan Preschool Children

Grant¹,

Suchdev²,

Flores‐Ayala³

et al. 2011

SciVee

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“…I. Thurnhampresent in many apparently healthy infants and children in developing countries and this can lead to an overestimate of vitamin A deficiency (19,20) . In contrast to vitamin A, plasma ferritin concentrations are increased by inflammation.…”

Section: Effect Of Immune Response On Nutrients and Nutrient Biomarkersmentioning

confidence: 99%

Interactions between nutrition and immune function: using inflammation biomarkers to interpret micronutrient status

Thurnham

2013

Proc. Nutr. Soc.

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The immune response promotes a complex series of reactions by the host in an effort to prevent ongoing tissue damage, isolate and destroy the infective organism and activate the repair processes that are necessary for restoring normal function. The homoeostatic process is known as inflammation and the early set of reactions that are induced are known as the acute phase response (APR). The APR has marked effects on the circulation, metabolism in the liver and the plasma concentration of many nutrients. The changes in nutrient concentrations follow a cyclic pattern; occurring before any clinical evidence of disease, being at their most pronounced during the disease and remaining in convalescence when all evidence of disease or trauma has disappeared. Therefore, where susceptibility to disease is high as in people who are HIV+ but still apparently healthy, obtaining an accurate measurement of nutritional status may not be possible. Accurate measurements of status are important for national statistics to plan for the proper utilisation of government resources and they are especially important to evaluate the effectiveness of nutritional interventions. Many acute phase proteins (APP) are synthesised during inflammation and they are used to monitor the progress of disease and recovery but, individually, none of their lifecycles compare well with those of the nutritional biomarkers. Nevertheless, recognising the presence of inflammation can help interpret data and, using two APP, this review paper will illustrate the methods we have developed to assist interpretation of plasma retinol, ferritin and zinc concentrations in apparently healthy, HIV+, Kenyan adults.

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“…Although only two of the young people (two girls aged 7-10 y) had plasma ACT concentrations above the normal upper limit of 0.65 g/l (Calvin & Price, 1986), associations with nutrient status may exist below this cutoff point. For example, raised plasma concentrations of ACT have been associated with reduced plasma concentrations of retinol (Paracha et al, 2000) and Zn (Goode et al, 1991). WBC counts are increased by infection or inflammation.…”

Section: Other Blood Analytesmentioning

confidence: 99%

Zinc and vitamin A intake and status in a national sample of British young people aged 4–18 y

2004

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Objective: To examine zinc and vitamin A intake and status and associated dietary, socio-demographic, lifestyle and physiological factors in British young people. Design: National Diet and Nutrition Survey of young people aged 4-18 y. Setting: Great Britain, 1997. Subjects: Complete 7-day weighed dietary records were provided by 1520 participants, while 1193 provided blood samples. Results: A total of 13 and 11% of participants respectively reported low dietary intakes of zinc and vitamin A (retinol equivalents), relative to the UK lower reference nutrient intake. These percentages were not altered significantly by including contributions to intake from supplements, mainly containing vitamin A (as retinol). Likelihood of low zinc and/or vitamin A intake was more often associated with age, sex and likely under-reporting of food consumption than with other sociodemographic and lifestyle factors. Low zinc and vitamin A intakes were generally less likely in those with higher consumption of dairy foods (mainly milk). Zinc and vitamin A status (assessed by plasma zinc and retinol concentrations) were adequate in almost all participants. Plasma zinc concentration was not significantly associated with zinc intake. Plasma retinol concentration was correlated with vitamin A intake (overall r ¼ 0.17, Po0.001; adjusted for age and plasma a 1 -antichymotrypsin concentration) and increased significantly with age (Po0.001) in both sexes. A significant association was found between plasma zinc and retinol concentrations in boys only (r ¼ 0.17, P ¼ 0.001). Conclusion: Zinc and vitamin A intakes and status were generally adequate in this national sample of British young people. Sponsorship:Food Standards Agency, UK.

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Interpretation of vitamin A status in apparently healthy Pakistani children by using markers of subclinical infection

Cited by 66 publications

References 21 publications

Correcting for Inflammation Changes Estimates of Iron Deficiency among Rural Kenyan Preschool Children

Correcting for Inflammation Changes Estimates of Iron Deficiency among Rural Kenyan Preschool Children

Interactions between nutrition and immune function: using inflammation biomarkers to interpret micronutrient status

Zinc and vitamin A intake and status in a national sample of British young people aged 4–18 y

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