Vitamin A deficiency in pre-school age Congolese children during malarial attacks. Part 1: Utilisation of the impression cytology with transfer in an equatorial country

The vitamin A status of 454 pre-school age Congolese children was evaluated by the impression cytology method with transfer (ICT) and by the determination of plasma retinol. The absence of goblet cells and the presence of enlarged epithelial cells indicate a peripheral deficit of vitamin A. A level of plasma retinol lower than 10 micrograms/dl is an indicator of vitamin A deficiency. The subjects were children in good health or suffering from malaria, measles or various infectious diseases. Advantages, disadvantages, sensitivity and specificity of the ICT are discussed. We suggest its use in a mass screening program for vitamin A deficiency in developing countries.     

Assessment of the vitamin A status of preschool and school age Senegalese children during a cross-sectional study.

The increasing concern about vitamin A deficiency in even its mild subclinical form has created the need for a mass screening test. Various clinical, biochemical and cytological methods for assessing the vitamin A status have been widely used but all are unsatisfactory for technical, ethical or public health reasons. The two prevalence criteria defined by the World Health Organization (WHO) for a vitamin A deficiency problem of public health significance are xerophthalmia and serum retinol concentrations. Recently we proposed a prevalence criterion for impression cytology with transfer (ICT) at the level of 50% of ICT results being abnormal. We conducted a cross-sectional survey of the prevalence of vitamin A deficiency and also undernutrition during the dry season in a random sample of 1,259 children (n = 442 for the 2-6 years and n = 817 for the 7-14 years) from a rural area in Senegal. Prevalence was 0 times and 4.2 times the WHO criteria for xerophthalmia and deficient serum retinol levels, respectively in preschool children. Abnormal ICT results were more frequent in preschool than in school children (53.4% versus 21.0%). There was an association between abnormal ICT results and stunting. Vitamin A deficiency was a public health problem in preschool children as assessed by the biochemical criterion (20.9% of serum retinol values under 0.35 mumol/l) or the cytological cut-off (53.4% of abnormal ICT results) but was also found in school children (21.0% of abnormal ICT results).     

Assessment of vitamin A status in an elderly French population using impression cytology with transfer

The vitamin A status of 105 elderly French people was assessed by ocular impression cytology with transfer (ICT). 5 patients (4.8%) had a negative ICT defined by the absence of goblet cells and the enlargement of the epithelial cells (deficient vitamin A status). 100 patients had a positive ICT with goblet cells and small, numerous epithelial cells (sufficient vitamin A status). ICT results were compared to serum biochemical parameters. Mean serum levels of retinol, retinol-binding protein (RBP) and transthyretin (TTR) were significantly lower while C-reactive protein (CRP) and orosomucoid were significantly higher in negative ICT than in positive one. The etiology of vitamin A deficiency is difficult to conclude (malnutrition, vitamin A deficiency, inflammation). ICT is a good indicator of peripheral vitamin A deficiency in our experience.     

Prevalence of malnutrition and vitamin A deficiency in the Diourbel, Fatick, and Kaolack regions of Senegal: a controlled study

Two hundred and six Senegalese preschool children included in an epidemiological study were selected by their results from impression cytology with transfer (ICT) for assessment of their nutritional state by means of biological variables and for assessment of the diagnostic values of the ICT. A problem of protein-calorie malnutrition existed (transthyretin and retinol-binding protein concentrations were low) associated with vitamin A deficiency (retinol concentrations were low). The sensitivity and specificity of the ICT defined with respect to retinol (threshold fixed at 0.35 mumol/L) varied with the classification criteria of ICT and seemed to be fairly insensitive but specific.     

Conjunctival impression cytology with transfer as a field-applicable indicator of vitamin A status for mass screening.

The increasing importance of vitamin A deficiency in even its mild subclinical form underlines the need for a mass screening test. Clinical, biochemical and cytological methods of assessing vitamin A deficiency in a public health setting have been described and widely used. The cytological method shows promise because it enables early detection of vitamin A deficiency. However interpretation is problematic since histopathological changes are gradual with the progressive disappearance of goblet cells and appearance of enlarged epithelial cells. The reliability and validity of the impression cytology with transfer (ICT) test were assessed in order to produce a meaningful standard for this cytological method. The ICT test was performed in Senegal on 1451 children, in the course of two surveys conducted in 1989 and 1990 in rural areas. Reliability, estimated by Cohen's kappa test for evaluating intra-reader variability, and sensitivity were highest for the abnormal-normal classification (kappa = 0.91; 95% confidence interval (CI): 0.89-0.93; and sensitivity = 74%; 95% CI 66-82%). The ICT method is a cheap, noninvasive and easy test to perform in the field. This method is also reproducible and fairly sensitive according to the abnormal-normal classification. As illustrated by our proposed 50% cutoff of abnormal cytology calculated in relation to 5% of serum retinol values below 0.35 mumol/L criterion, ICT only requires a small sample for the assessment of the overall health of a community in contrast to xerophthalmia and blood vitamin A deficiency tests.     

Vitamin A deficiency in pre-school age Congolese children during malarial attacks. Part 2: Impact of parasitic disease on vitamin A status

The vitamin A status of 454 pre-school age Congolese children was evaluated by the impression cytology method with transfer (ICT) and by the determination of plasma retinol. During malarial attacks, the vitamin A status is abnormal (deficient or marginal) in 40.8% of the children according to the ICT test and in 37.5% of the children who have plasma levels of retinol lower than 10 micrograms/dl. The mean concentration of plasma retinol in patients during malarial attacks (14.8 +/- 9.5 micrograms/dl) is significantly lower than the values found in other subjects (31.5 +/- 14.3 micrograms/dl) (p less than 0.001). A significant correlation was established between the results of the ICT test and two biochemical parameters (retinol, transthyretin). We conclude that there is a significant relationship between vitamin A deficiency and a malarial attack.     

Assessment of vitamin A deficiency in the Republic of Djibouti.

In a countrywide survey, we assessed the prevalence of vitamin A deficiency by clinical examination and impression cytology with transfer method (ICT) in a randomized sample of 2445 subjects representative of the population of the Republic of Djibouti. A plasma retinol determination was made on a part of this sample. Results lead to believe that serious vitamin A deficiency may periodically occur in Republic of Djibouti when nutritional conditions become poor. Meanwhile a large number of children, mostly in the rural area, have a marginal vitamin A status and are exposed to a high level of risk.     

Assessment of vitamin A deficiency in Republic of Malawi by impression cytology method.

During a countrywide survey, we assessed the prevalence of vitamin A deficiency by impression cytology method with transfer in a randomized sample of 650 representative of the children's population of the Republic of Malawi. A vitamin A deficiency was indicated by the results of the ophthalmic examination (XN = 1,4%; X2 = 0,2%) and the ICT test (22% with deficient cytology). Results of ICT were related to age. Vitamin A deficiency seems to be a public health problem in the Republic of Malawi.     

Assessment of vitamin A status of preschool children in a sub-Saharan African setting: comparative advantage of modified relative-dose response test

A nationally-representative sample of 2,696 preschool children living in Congo was examined during Au gust-September 2003 to determine the rates of vitamin A deficiency. Ninety clusters of 30 children, aged six months to six years, were selected, using a randomized two-level cluster-sampling method. Vitamin A deficiency was determined by assessing the prevalence of active xerophthalmia (nightblindness and/or Bitot spots) in the cross-over sample of 2,696 individuals. A semi-quantitative seven-day dietary questionnaire was concurrently applied to the mothers of children enrolled to estimate the latter's consumption of vitamin A-rich food. Vitamin A status was assessed by performing the modified relative dose-response test (MRDR) on dried blood spots (DBS) from a subsample of 207 children aged less than six years and the impression cytology with transfer (ICT) test on a subsample of 1,162 children. Of the children enrolled, 5.2% suffered from nightblindness, 8.0% had Bitot spots, and 2.5% had other vitamin A deficiency sequellae. Fifty-three percent of the ICT tests showed the presence of vitamin A deficiency. The biochemical MRDR test showed that the vitamin A status of 30% of the study children was critical. Twenty-seven of them had retinol levels of < 10 microg/dL [mean +/- standard deviation (SD) 7.02 +/- 2.0 microg/dL], and 50% had retinol levels of 10-20 microg/dL (mean +/- SD 14.2 +/- 2.83 microg/dL). The poor health status and low rates of consumption of vitamin A-rich food are the main factors determining critical status. Vitamin A deficiency, reflecting poor nutrition and health, is a serious public-health issue among children aged less than six years in Congo.     

Vitamin A status of children in Sri Lanka.

A representative country-wide rural nutrition status survey determined the extent and distribution of vitamin A deficiency in Sri Lanka in children 6 through 71 months of age. Trained paramedical personnel recorded the presence or absence of selected ophthalmological signs and symptoms associated with vitamin A deficiency in 13,450 children. The results of the country-wide clinical survey indicate that a vitamin A deficiency problem of public health importance may exist in two of 15 health areas. Serum vitamin A levels were determined on 346 survey children from two of 15 health areas and compared with clinical findings for these areas. The lowest mean serum vitamin A, 26.3 microgram/100 ml, occurred in children with clinical eye findings. A high prevalence of clinical eye findings, 34%, and the low mean serum vitamin A value, 28.2 microgram/100 ml, were found in the group of chronically undernourished children--children who are less than 90% of their expected height for age. The survey results enabled planned redirection of the distribution of vitamin A capsules to preschool children in Sri Lanka to areas shown to have the highest prevalences of ophthalmological signs and symptoms and/or the highest prevalence of chronic undernutrition.     

The prevalence of vitamin A deficiency in 1994 on an atoll of the Marshall Islands and its relationship to locally grown food

In an area of the world not previously studied for the presence of nutritional deficiencies, this study conducted in 1994, examined the prevalence of Vitamin A deficiency on a representative atoll of the Marshall Islands. All children ages three through ten living on Mili atoll were surveyed. The study was conducted house-to-house with all 38 subjects on the atoll voluntarily enrolling in the study. Vitamin A status was assessed by conjunctival impression cytology with transfer ([CT), clinical ophthalmic signs, and nutritional survey in all children ages three through ten living on Mili atoll, Republic of the Marshall Islands. Forty-seven percent had xerophthannia (5% with XN, 39% with XN + XIA, and 3% with XN + XIB). More than three-quarters (78%) were ICT abnormal, indicating 31% of the population had mild sub-clinical vitamin A deficiency. Eighty-six percent of the children had not received the U.S. recommended daily allowance of vitamin A in the previous week. Oiven the World Health Organization's published guidelines that anything greater than a 1% prevalence, Vitamin A deficiency on Mili atoll may be classified as a significant public health problem.     

Urbanisation and vitamin A deficiency in children: Comparison between a traditional district and a new settlement in Mali

Objectives: The purpose of this study was to assess the vitamin A status of pre-school urban children and to compare the situation between a traditional district and a new settlement after two decades of intense urbanisation. Subjects and methods: A cross-sectional stratified survey was carried out in Bamako, Mali, on a representative sample of children (aged 4–6 years). 532 children were involved from a traditional district and 453 from a new settlement (NS). The vitamin A status was assessed by: clinical indicators (ophthalmic examination), subclinical indicators (questionnaire looking for night blindness, impression cytology with transfer test (ICT), modified relative dose response test (MRDR), and a diet inquiry about vitamin A intakes. Acute malnutrition was assessed by a weight/height measure. Results: In both districts, all the clinical indicators were below the WHO criteria that define a public health problem. Both the ICT test, respectively 19 and 21% of abnormal tests, and the MRDR, 67.3 and 73.1% of tests 0.06, indicated a subclinical vitamin A deficiency as defined by WHO thresholds. During the preceding week only four children in NS had consumed vitamin A-rich food less than seven times. No significant difference between the two districts was found either for clinical or subclinical indicators (p > 0.5). Conclusion: Despite a rapid urbanisation, the vitamin A status of the children seemed to be rather homogeneous among the different districts. The population remained vulnerable with peripheral depletion and low hepatic stores of vitamin A. The urban children should be carefully monitored regarding vitamin A status.     

儿童维生素A缺乏与感染性疾病的关系

[目的]了解儿童血清维生素A缺乏(vitamin A deficiency,VAD)与感染性疾病的关系. [方法]在避光条件下采集儿童指血、分离血清,以严格的质量控制,用微量荧光法检测血清维生素A(vitamin A,VA)浓度. [结果]两周内不同地区儿童发热率、急性呼吸道感染(ARI)、腹泻,发病率随血清VA缺乏率的增加而增加;儿童平均血清VA的含量随发热率、发病率的增加而下降. [结论]我国儿童血清VA含量低、缺乏率高的儿童不论个体或群体都表现为易于发生急性感染疾病,VAD是引起儿童易于发生急性感染性疾病的重要原因之一.     

Prevalence of Vitamin A Deficiency in Pregnant and Lactating Women in the Republic of Congo

Vitamin A status in a sample of pregnant and lactating women living in several representative regions of Congo was assessed and compared between August and September 2004. This survey was conducted using a randomized two-stage cluster-sampling method with stratification on 90 clusters, each consisting of at least 15 women. Vitamin A status was determined in a total of 1,054 individuals, using the impression cytology with transfer (ICT) test, the modified relative dose response test (MRDR test) on dried blood spots (DBS), and clinical examination to detect signs of xerophthalmia. The clinical criterion defining vitamin A deficiency was the presence of active xerophthalmia (Bitot''s spots [X1B]), active corneal disease), and/or night blindness (XN stage). The prevalence of clinical signs of stage XN and X1B xerophthalmia in the Republic of Congo was found to be 16% and 19% respectively. The prevalence of clinical signs (X1B) was greater in the rural north than in urban areas, with a gradient running from urban (5%) to rural area (33%); 27% of all the ICT tests showed that the subjects were suffering from vitamin A deficiency. The deficiency rates were significantly higher (p<0.001) in urban surroundings (Brazzaville) than in the rural northern regions. The biochemical MRDR test showed the presence of vitamin A deficiency (≥0.06) in 26% of the mothers in Brazzaville compared to 6% in the town of Kouilou; 44% of the women had retinol levels of <10 μg/dL in the rural north whereas these percentages were significantly lower in the urban areas surveyed (chi-square=62.30, p<0.001). A significant correlation was found to exist (p<0.001) between the ICT test and the MRDR test on DBS. In the population as a whole, 30% of the mothers suffering from malarial attack had abnormally low MRDR levels (≥0.06) compared to no malaria. The results of the present study confirm that vitamin A deficiency is a serious public-health issue in pregnant and lactating mothers in the Republic of Congo.Key words: Dried blood spots, Lactating women, Pregnant women, Vitamin A deficiency, Congo     

维生素A对4~6岁儿童白细胞数量及其分类的影响

目的 了解东莞市4~6岁儿童维生素A缺乏现状,以及维生素A水平对白细胞计数及其分类的影响,为进一步研究提供理论支持。方法 采用随机抽样调查的方法,于2017年4-8月选取东莞市无现患疾病的4~6岁儿童进行血常规及维生素A浓度检测,其中五分类血常规采用全自动血细胞分析仪检测;维生素A浓度采用高效液相色谱法(HPLC)检测。结果 维生素A缺乏人数占总调查人数的34.97%(539/1 687)。男童嗜酸粒细胞计数、嗜碱粒细胞计数及单核细胞计数高于女童。随着年龄增长,单核细胞及淋巴细胞数量逐渐降低。4岁及6岁组儿童维生素A缺乏组淋巴细胞数量低于维生素A正常组;而在5岁组儿童,维生素A缺乏组中性粒细胞高于维生素A正常组。结论 东莞市4~6岁儿童维生素A缺乏状况仍较严重,并可对淋巴细胞计数及中性粒细胞计数产生影响。     

Vitamin C: should daily administration keep the paediatrician away?

Vitamin C is an organic compound that is almost ubiquitous in the daily diet of individuals. There are clear indications of supplementation when secondary deficiency is detected related with reduced dietary intake or reduced absorption. On the other hand, indications for supplementation concerning an increased need are controversial. Several authors have studied the role of vitamin C as an adjuvant in the treatment of diseases that may affect children and adolescents. These diseases affect all organs and systems: specifically, vitamin C supplementation could play a role in respiratory, neurological, psychiatric, oncohematological, nephrological, ophthalmological and nutritional disorders. In paediatric age, a significant benefit of vitamin C supplementation has been observed in depressive pathology, iron-deficiency anaemia and chronic renal failure related to haemodialysis. No evidence was found with vitamin C supplementation on mortality, cognitive performance, quality of life, eye diseases, infections, cardiovascular diseases and tumours. This evidence may be related to the fact that in developed countries, vitamin C is almost ubiquitous in the daily diet of each individual. In conclusion, studies on non-industrialised populations in which there could be a real benefit from such supplementation, have yet to be conducted.     

Investigation and treatment of vitamin A deficiency in children suffering from malnutrition

In Benin, physicians performed the ocular impression test on 18 malnourished children admitted to the university pediatric service in Cotonou to determine the occurrence of vitamin A deficiency. They put a millipore filter paper on the enlarged conjunctiva to lift off cells, which were then transferred to a slide. After the cells had been colored and fixed, laboratory personnel examined the cells under the microscope. Only one malnourished child had normal conjunctival cells. 17 children had vitamin A deficiency. The ocular impression of 7 of them indicated a deficiency of conjunctival cells (a prevalence of 39%). Among healthy children, 12.6% had vitamin A deficiency. 2 children presented at the hospital with an ulceration of the cornea in the right eye, which had developed into blindness. A diet rich in vitamin A in the form of palm oil supplemented with 100,000 units of vitamin A provided treatment of vitamin A deficiency among the malnourished children. Two months after treatment the ocular impression test revealed that the eyes had returned to normal.     

重庆市某郊区学龄前儿童维生素A营养状况及其影响因素分析

目的:了解学龄前儿童维生素A营养状况,并对其影响因素进行分析,为制定适当的干预措施提供科学依据。方法:采用整群抽样,对重庆市某郊区8个幼儿园3～6岁878名儿童进行现况调查,包括身体测量指标检查、生化指标检查(用高效液相色谱测定血清视黄醇)及相关影响因素问卷调查。结果:儿童血清视黄醇(VA)平均值(1.064±0.272)μmol/L,VA缺乏(VA浓度<0.7μmol/L)的检出率为22.41%(234/878),亚临床缺乏(0.7μmol/L相似文献   

Vitamin A deficiency,iron deficiency,and anemia among preschool children in the Republic of the Marshall Islands

OBJECTIVE: We investigated the co-occurrence of vitamin A deficiency, iron deficiency, and anemia among young children in the Republic of the Marshall Islands. METHODS: Hemoglobin, serum retinol, and serum ferritin were assessed in the Republic of the Marshall Islands Vitamin A Deficiency Study, a community-based survey that involved 919 children ages 1 to 5 y. RESULTS: The proportion of children with vitamin A deficiency (serum retinol concentrations < 0.70 microM/L) was 59.9%. The prevalences of anemia (hemoglobin < 110 g/L), iron deficiency (serum ferritin < 12 microg/L), and iron deficiency anemia (iron deficiency and anemia) were 36.4%, 53.5%, and 23.8%, respectively. The proportion of children who had co-occurrence of vitamin A and iron deficiencies was 33.2%. The mean ages of children with and without vitamin A deficiency were 3.2 +/- 1.4 and 2.9 +/- 1.5 y, respectively (P = 0.01), and the mean ages of those with and without iron deficiency were 2.7 +/- 1.3 and 3.5 +/- 1.4 y, respectively (P < 0.0001).CONCLUSIONS: Children in the Republic of the Marshall Islands, ages 1 to 5 y, are at high risk of anemia, vitamin A deficiency, and iron deficiency, and one-third of these children had the co-occurrence of vitamin A and iron deficiencies. Further investigation is needed to identify risk factors and evaluate interventions to address vitamin A and iron deficiencies among children.     

Prevalence of malnutrition and vitamin A deficiency in the Diourbel, Fatick, and Kaolack regions of Senegal: epidemiological study

The purpose of our study was to determine the prevalence of protein-calorie malnutrition (PCM), ocular diseases, and vitamin A deficiency in preschool children selected at random in a rural zone of the groundnut belt of Senegal. The prevalence of PCM was 37.1% (95% CI 33.8-40.2%) according to the Waterlow classification, with a majority of stunting, and prevalence of hypovitaminosis A was estimated to be 11.4% (95% CI 9.3-13.5%) by using impression cytology. Furthermore, 19.4% (95% CI 15.8-22.0%) of the children might be defined at risk of deficiency. The prevalence of Bitot's spots was equal to 0.2% (95% CI 0.03-0.9%). A problem of PCM associated with a health-endangering vitamin A deficiency existed.