Pupillary and visual thresholds in young children as an index of population vitamin A status

Congdon, Nathan; Sommer, Alfred; Severns, Matthew L.; Humphrey, Jean H.; Friedman, David S.; Clement, Liliana; Wu, Lee; Natadisastra, Gantira

doi:10.1093/ajcn/61.5.1076

Cited by 38 publications

(12 citation statements)

References 18 publications

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“…Even though in young children, cases had worse pupillary threshold measurements than controls, these differences were not statistically significant. However, as in previous studies in young Indian and Indonesian children and pregnant/breast-feeding women in Nepal (Congdon et al, 1995), poor pupillary thresholds were significantly associated with low serum retinol concentration in Tanzanian children and women.…”

Section: Xn Validation Studysupporting

confidence: 71%

“…The mean pupillary threshold measurements in this Tanzanian population were surprisingly good (Table 4) compared with those detected in vitamin A deficient populations in India (-0.622 log cd/m 2 ), Indonesia (-0.985 log cd/m 2 ) and Nepal (-1.11 to -1.24 log cd/m 2 ) (Congdon et al, 1995;Sanchez et al, 1997;Congdon et al, 2000). As the study population was clearly vitamin A deficient, one potential explanation for this unexpected result could be that waiting in a fairly dark room prior to dark adaptation decreased the participants' threshold.…”

Section: Xn Validation Studymentioning

confidence: 62%

“…Participants had been dark-adapted for 10 min after exposure to a camera flash. A standard test protocol developed by Congdon et al (1995) was used. All the examinations were carried out by the same examiner, a sixth-form secondary school leaver with previous research experience who was not aware of the participants' XN status.…”

Section: Pupillary Threshold Measurementsmentioning

confidence: 99%

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Validation of night blindness reports among children and women in a vitamin A deficient population in rural Tanzania

et al. 2004

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Objective: This study validates different definitions of reported night blindness (XN) in a vitamin A deficient African population with no local term for XN. Design: Case-control study with follow-up after treatment. Setting: Eight primary schools and health centres in rural Tanzania. Subjects: A total of 1214 participants were screened for reported XN and other eye signs of xerophthalmia: 461 children aged 24-71 months, 562 primary school-age children and 191 pregnant or breast-feeding women. All 152 cases of reported XN were selected for the validation study and group matched with 321 controls who did not complain of XN. XN reports were validated against serum retinol concentrations and pupillary dark adaptation measurements in cases and controls. Intervention: All children and women who reported XN or had other signs of active xerophthalmia were treated with vitamin A and followed up 3-4 weeks later. Half of the untreated control group who had their serum retinol examined in the baseline examination were also followed up. Results: The overall prevalence of reported XN was 12.5%. At baseline, mean pupillary threshold (-1.52 vs -1.55 log cd/m 2 , P ¼ 0.501) and median serum retinol concentrations (0.95 vs 0.93 mmol/l, P ¼ 0.734) were not significantly different in cases and controls either overall or in each population group. More restricted case definitions reduced the prevalence of reported XN to 5.5% (Po0.001), but there was still no significant difference between cases and controls although the results were in the expected direction. After treatment, the median serum retinol concentration improved significantly only in the most deficient group, the young children. Dark adaptation improved in all the subgroups but the difference was only significant for young children and primary school-age children when the restricted case definitions were used. Conclusions: XN reports are a poor indicator of vitamin A deficiency in this population. Sponsorship: Task Force Sight and Life, Basel, Switzerland.

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Section: Xn Validation Studysupporting

confidence: 71%

Section: Xn Validation Studymentioning

confidence: 62%

Section: Pupillary Threshold Measurementsmentioning

confidence: 99%

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Validation of night blindness reports among children and women in a vitamin A deficient population in rural Tanzania

et al. 2004

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“…This implies that there is still a need for guidelines for interpretation of blood retinol levels in adults, special risk groups and children. Likewise, there is a need to establish dark adaptation reference values by using devices that are simpler and more portable than the Hartlinger dark adaptometer and that can easily be used in field settings (Congdon et al, 1995).…”

Section: Discussionmentioning

confidence: 99%

Dark adaptation pattern of pregnant women as an indicator of functional disturbance at acceptable serum vitamin A levels

Wondmikun

2002

Eur J Clin Nutr

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Background: As a result of lack of precise guidelines, nutritional surveys on adults and high-risk groups are using diverse reference values as a dividing line between normal and deficient vitamin A status. Objective: To investigate whether pregnant women at marginally normal serum retinol status exhibit functional alteration that are characteristic of a deficiency state. Setting: Antenatal clinic, Gondar teaching hospital. Subjects: Ninety-six healthy pregnant women were recruited for the study at the antenatal clinic. Intervention: The dark adaptation time was tested in 48 pregnant women with marginal serum retinol level. The time lapse to see successive light stimuli of diminishing luminescence grade and change in retinal sensitivity pattern was measured using dark adaptometer. Results were compared with the results of a control group of women of similar age, parity and gestational period but with serum retinol values above 35 mg=dl. Results: The mean serum retinol levels of cases and controls were 23.35 mg=dl and 40.47 mg=dl respectively (P < 0.008). Cases have a lower dark adaptation than their controls, shown by their remarkably reduced sensitivity to light. For instance at mean final light threshold was 72.20 AE 0.11 log cd=m 2 in cases as compared to 72.88 AE 0.1 log cd=m 2 in the normal group (P < 0.001). Conclusion: During pregnancy, dark adaptation was strongly associated with serum retinol concentration and women with marginal vitamin A concentration had lower dark adaptation. Hence marginally normal serum retinol levels should be categorized as a deficiency state, at least in pregnant women.

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“…É reconhecida sua importância na diferenciação celular, no funcionamento normal dos epitélios, da visão, na morfogênese, na resposta imune, no crescimento. Nos olhos os sinais e sintomas da carência de vitamina A costumam ser muito mais evidentes, e prevalentes; além disso, se não houver tratamento, a marcha progressiva de sua gravidade pode chegar à cegueira irreversível (Sommer, 1989;Sommer et al, 1981;Blomhoff et al, 1992, Congdon et al, 1995McLaren & Frigg, 1997). Paradoxalmente, entretanto, é a causa de cegueira de mais fácil prevenção em crianças de todo o mundo (WHO, 1994(WHO, , 1995.…”

Section: Introductionunclassified

Ingestão e hábitos alimentares de pré-escolares de três capitais da Amazônia Ocidental Brasileira: um enfoque especial à ingestão de Vitamina A

Marinho

Roncada

2003

Acta Amaz.

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RESUMO -Com objetivo de avaliar o consumo de energia, vitamina A, zinco e proteínas, bem como os hábitos alimentares de pré-escolares das capitais de Roraima (Boa Vista),Amazonas (Manaus) e Rondônia (Porto Velho) foi realizado um inquérito alimentar em 54, 238 e 78 crianças de ambos os sexos (sub-amostra de inquérito nutricional mais abrangente),respectivamente, em creches e pré-escolas, mediante os métodos recordatório de 24 horas e de freqüência de consumo de alguns alimentos fontes de vitamina A, em entrevista com a mãe ou responsável pela criança. Os resultados mostram que os alimentos mais consumidos foram pão, bolacha e biscoito, com 98,3%, seguidos pelo açúcar (95,1%), arroz (92,4%), óleo vegetal (86,0), farinha de mandioca (77,4%), tomate (70,1%) e café (69,5%). O consumo de alimentos de origem animal foi responsável por quase dois terços do total ingerido de vitamina A. Quanto à distribuição dos alimentos fontes de vitamina A, observou-se semelhança do seu consumo nas três cidades estudadas. O percentual de adequação de consumo evidenciou que a proteína foi o único nutriente consumido em níveis superiores à recomendação da "National Research Council", enquanto o aporte dietético de vitamina A foi de 84,0%, 68,4% e 63,8%, em Boa Vista, Manaus e Porto Velho, respectivamente, com inadequação, inclusive, para energia e zinco. Observou-se um padrão alimentar monótono e limitado, com baixo consumo de fontes de vitamina A pré-formada, de hortaliças e de frutas fontes de carotenóides pró-vitamínicos A típicos da Região Amazônica, como buriti, tucumã, pupunha e manga, quase todas sazonais, que não estavam na sua época por ocasião do inquérito. ABSTRACT -The objective of this study was to evaluate the intake of energy, vitamin A, zinc and protein, as well as food habits of 54, 238 and 78 pre-school children of both sexes, 3 to 6 years old, (wide hange of subsample of inquiry including nutritional), in the capitals of Roraima (Boa Vista),Amazonas (Manaus) and Rondônia (Porto Velho), respectively. Dietary assessments were performed with the parents or someone responsible for the child, using the 24 hour recall and food frequency questionnaire methods. Our results showed that bread, crackers and cookies were the most consumed foods (98,3%), followed by sugar (95,1%), rice (92,4%), vegetable oil (86,0), manioc flour (77,4%), tomato (70,1%) and coffee (69,5%).The intake of animal products was responsible for almost 2/3 of the total intake of vitamin A. The pattern of vitamin A sources consumption among the three cities was similar. Protein was the only nutrient in which the intake exceeded the recommendation, whereas zinc and energy intake were inadequate. Additionally, the consumption of vitamin A was, respectively, 84,0%, 68,4% and 63,8% in Boa Vista, Manaus and Porto Velho, of the recommended values. A monotonous and limited dietary pat-ACTA AMAZONICA 33(2): 263-274 Palavras-chave:

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Pupillary and visual thresholds in young children as an index of population vitamin A status

Cited by 38 publications

References 18 publications

Validation of night blindness reports among children and women in a vitamin A deficient population in rural Tanzania

Validation of night blindness reports among children and women in a vitamin A deficient population in rural Tanzania

Dark adaptation pattern of pregnant women as an indicator of functional disturbance at acceptable serum vitamin A levels

Ingestão e hábitos alimentares de pré-escolares de três capitais da Amazônia Ocidental Brasileira: um enfoque especial à ingestão de Vitamina A

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