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).     

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.     

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     

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.     

2015年中国农村孕妇维生素A营养状况

目的 评价中国农村孕妇维生素A的营养状况.方法 数据来自2015年"中国成人慢性病与营养监测",共调查了 3273名孕妇,采用高效液相色谱法测定血清中视黄醇含量,采用免疫透射比浊法测定C反应蛋白和α-酸性糖蛋白.分析孕妇视黄醇含量在不同地域、年龄、民族、体质指数、文化程度、孕周、人均家庭收入及不同炎症状态下的分布情况,...     

Prevalence of malnutrition and vitamin A deficiency in the Diourbel, Fatick, and Kaolack regions of Senegal: feasibility of the method of impression cytology with transfer

The evaluation of the prevalence of ophthalmological diseases and vitamin A deficiency in Senegalese preschool-aged children enabled us to confirm the method of impression cytology with transfer (ICT) and to assess the impact of ophthalmological diseases on the cytological appearance of conjunctival cells. A simplification of the ICT method consisted of transferring cells present on a strip of paper to a glass slide by finger pressure. Harris-Schorr staining of the sample papers confirmed the results obtained by the transfer. Inflammatory trachoma influenced the results of the test. This simple method will prove very helpful for detection of vitamin A deficiency in children in underdeveloped areas.     

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.     

A prevalence study of vitamin A deficiency and xerophthalmia in northeastern Thailand

An epidemiologic survey of the prevalence of xerophthalmia and vitamin A deficiency was conducted in May and June 1985 in a multistage random sample of 1,772 children 1-8 years of age from 16 rural villages and the capital city of the Sakon Nakhon province in northeastern Thailand. Data of clinical eye examinations were available for 92% (n = 903) of the eligible children aged 1-5 years (n = 982); history of night blindness was obtained from a reliable source from 93% (n = 1,644) of the whole sample; and biochemical data were available for 60% (1,060) of the children examined. The distribution of clinical signs of xerophthalmia and serum retinol levels differed between the rural and urban areas. In the urban area, no signs of xerophthalmia or deficient serum retinol levels were found in the preschool children examined. The prevalence of night blindness in the rural area was 1.3% in children aged 1-5 years (95% confidence interval (Cl) 0.7-1.9); Bitot's spots were seen in 0.4% (95% Cl 0.1-1.0); 12.7% (95% Cl 9.9-15.5) showed deficient serum retinol levels (less than 0.35 mumol/liter). Of the children aged 1-8 years, 9.6% (95% Cl 7.8-11.4) showed deficient serum retinol levels. In the rural area, the prevalence of night blindness, Bitot's spots, and deficient serum retinol levels indicates a problem of public health importance according to World Health Organization criteria.     

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 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 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.     

Conjunctival impression cytology for assessment of vitamin A status

Ocular signs and serum vitamin A concentrations are commonly used for the diagnosis of vitamin A deficiency. Recently, impression cytology was suggested as a method for early detection of this condition. A clinical trial was conducted to compare the results of impression cytology with the other two indicators of vitamin A status. A total of 246 children aged 1-10 y were investigated. About 25% of the children with normal eyes showed abnormal cytology. Their mean vitamin A concentrations were significantly lower compared with those with normal cytology, which suggests that abnormal cytology reflects subclinical deficiency. After treatment with vitamin A, most of the children who had abnormal cytology at baseline examination showed improvement. These observations suggest that abnormal cytology is specific to vitamin A deficiency. Impression cytology is a relatively simple technique and can be used for assessing the magnitude of the problem, especially in communities where the prevalence of clinical disease is low.     

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.     

Elevated vitamin A intake and serum retinol in preadolescent children with cystic fibrosis

BACKGROUND: Persons with cystic fibrosis (CF) and pancreatic insufficiency (PI) are at risk of vitamin A deficiency because of steatorrhea, despite pancreatic enzyme replacement. Long-standing vitamin A supplementation may increase the risk of vitamin A toxicity. OBJECTIVE: The aim was to describe the vitamin A intake and serum retinol concentrations of preadolescent children with CF, PI, and mild-to-moderate pulmonary disease, who were cared for under current practice recommendations. DESIGN: This cross-sectional study evaluated children aged 8.0-11.9 y with CF and PI from 13 US CF centers. Dietary and supplemental vitamin A intakes were compared with the Dietary Reference Intakes (DRIs) for healthy children, CF recommendations, and data from the National Health and Nutrition Examination Survey (NHANES), 1999-2000. Serum retinol concentrations were compared with NHANES data. RESULTS: The 73 subjects with CF had a dietary vitamin A intake of 816 +/- 336 microg retinol activity equivalents (165 +/- 69% of the recommended dietary allowance), which was similar to the NHANES value. The supplement intake provided 2234 +/- 1574 microg retinol activity equivalents/d and exceeded recommendations in 21% of the subjects with CF. Total preformed retinol intake exceeded the DRI tolerable upper intake level in 78% of the subjects with CF. The serum retinol concentration was 52 +/- 13 microg/dL (range: 26-98 microg/dL), which was significantly higher than the NHANES value (37 +/- 10 microg/dL; range: 17-63 microg/dL; P < 0.001). CONCLUSION: Although supplementation helps to prevent vitamin A deficiency in children with CF and PI, their high vitamin A intakes and serum retinol concentrations suggest that usual care may result in excessive vitamin A intake and possible toxicity that would increase the risk of CF-associated liver and bone complications.     

Association of serum concentrations of retinol and carotenoids with overweight in children and adolescents

OBJECTIVE: A study was conducted to verify the association between serum concentrations of retinol and carotenoids with overweight in children and adolescents. METHODS: In total 471 children (7-9.9 y of age) and adolescents (10-17 y of age), living in a poor region of the city of Rio de Janeiro, Brazil, were assessed. Serum concentrations of retinol and carotenoids were assessed by high-performance liquid chromatography, and cutoffs for inadequacy of retinol and carotenoids were <30 and <40 microg/dL, respectively. Overweight was defined by the sex- and age-specific body mass index cutoffs recommended by World Health Organization. The logistic regression model was used to test the association of overweight, gender, and age range with low serum concentrations of retinol and carotenoids. RESULTS: Prevalences were 10% for low serum concentration of retinol, 55.8% for carotenoids, and 15.3% for overweight. Retinol inadequacy was significantly higher in adolescents (12.6%) than in children (6.8%). The average of carotenoids was significantly lower in overweight subjects (30.40 +/- 16.74 versus 43.06 +/- 25.26 microg/dL, P = 0.001). Overweight children and adolescents presented a greater chance of a decrease in serum concentrations of carotenoids (odds ratio 2.51, 95% confidence interval 1.43-4.39) when compared with non-overweight subjects. CONCLUSION: An important prevalence of vitamin A deficiency was found. Overweight children, as much as adolescents, may have a greater chance of presenting low concentrations of carotenoids and, hence, a lower antioxidant defense.     

WHO's mission for vision

The number of blind and visually impaired is expected to double by the year 2020; 90% of blind people live in developing countries. It is estimated that 80% of the world's blindness is preventable or curable. The World Health Organization (WHO) and a consortium of nongovernmental organizations (NGOs) have launched the Global Initiative for the Elimination of Avoidable Blindness. According to Dr. Bjorn Thylefors, Director of WHO's Programme for the Prevention of Blindness and Deafness, the global initiative will focus on disease control, human resource development, infrastructure, and technology. Priority will be given to the following: 1) cataracts, with a backlog of 16-20 million cases; 2) trachoma, the most common cause of preventable blindness with some 5.6 million blind and 146 million active cases in need of treatment; 3) childhood blindness caused by vitamin A deficiency, measles, conjunctivitis in the newborn, or retinopathy of prematurity; 4) river blindness (onchocerciasis); and 5) refractive errors and low vision. Treatment for trachoma will follow the surgery, antibiotics, facial cleanliness, and environmental hygiene strategy. Dr. Thylefors believes trachoma can be eliminated globally by 2020.     

眼结膜印迹细胞法评价维生素A营养状况的研究

本文以20名消化系统疾病病人和111名3～6岁健康幼儿为对象,检测眼结膜印迹细胞变化,并与血清维生素A浓度、维生素A相对剂量反应(RDR)进行比较,结果90％印迹细胞正常的病人血清维生素A浓度>0.7μmol/L,70％印迹细胞异常的病人血清维生素A浓度≤0.70μmol/L,经统计学处理,差异有极显著性意义(P<0.01);111名幼儿中有97.5％印迹细胞正常者的血清维生素A浓度>1.05μmol/L,64.2％印迹细胞异常者的血清维生素A≤1.05μmol/L,差异有极显著性意义(P<0.01)。故认为眼结膜印迹细胞法是一项简便,快速,有效的评价机体维生素A营养状况的指标,适合基层推广应用。     

Prevalence and predictors of low serum retinol and hypoalbuminaemia among children in rural Peninsular Malaysia

Vitamin A deficiency and malnutrition are still considered public health problems in rural areas of developing countries, including Malaysia. A cross-sectional exploration study was carried out on 281 Orang Asli (Aborigine) children aged between 2 and 15 years in Selangor, Malaysia. The overall prevalence of low serum retinol (<70 micromol/l) and hypoalbuminaemia (<35 g/l) were 25.2 and 7.8%, respectively. Univariate analysis showed that severe ascariasis, significant stunting and giardiasis were significantly associated with low concentration of serum retinol. As well as intestinal parasitic infections, low socio-economic status was a significant predictor of hypoalbuminaemia. Logistic regression analysis identified severe ascariasis and significant stunting as predictors of low serum retinol, while mixed intestinal parasitic infection and low household income were predictors of hypoalbuminaemia. In conclusion, control measures for intestinal parasitic infections should be included as one of the strategies for the prevention and control of malnutrition and vitamin A deficiency in this population.     

Prevalence of undernutrition and vitamin A deficiency in the Dogon Region,Mali

OBJECTIVES: A representative sample of 1510 preschool children living in the Bandiagra circle (Mopti Region, Mali) was examined between March and April 1997 to determine the level of vitamin A deficiency. METHODS: Using a randomized two level cluster sampling, 20 clusters of 75 children aged six months to six years were selected for evaluating xerophthalmia (XN night blindness and/or X1B Bitot spot). Concurrently stature and weight were determined. A semiquantitative seven-day dietary questionnaire was applied to the mothers of 484 infants to assess consumption of vitamin A rich foodstuffs. The prevalence of biochemical deficiency was attested using the Modified Relative Dose Response test (MRDR) on a sub-sample of 192. RESULTS: Of the studied children, 4.3% (95% Confidence interval [CI]: 3.2-5.3) reported night blindness and 2% (95% CI: 1.3-2.7) had Bitot spots. Prevalence of xerophthalmia attested by at least one of these signs was 5.4% (95% CI: 4.2-6.5). The prevalence reached 10.5% at three years of age. The MRDR test proved abnormal in 77.1% of the subjects (95% CI: 70.3-82.7). Serum retinol was lower than 0.35 micro mol/L in 43.8% (95.6% CI: 36.9-51.3) and less than 0.70 micro mol/L in 92.7% of the children (95% CI: 87.8-95.8). Weekly consumption of vitamin A rich food was rare: 75.8% had not eaten any animal vitamin A rich food, and 22.1% had consumed less than seven times a vitamin A rich food of either vegetable or animal origin. CONCLUSIONS: These data define vitamin A deficiency as a severe public health problem in the Bandiagara area of Mali.