Retinol binding protein as a surrogate measure for serum retinol: studies in vitamin A-deficient children from the Republic of the Marshall Islands

BACKGROUND: Serum retinol is transported by retinol binding protein (RBP), which has one high-affinity binding site for retinol; consequently, the molar ratio of retinol to RBP in the circulation is approximately 1 to 1. In vitamin A deficiency (VAD), both serum retinol and RBP decline. However, the retinol-RBP relation has not been well studied in populations with a high incidence of severe VAD. OBJECTIVE: The purpose of this study was to determine whether RBP is a good surrogate for serum retinol at the very low retinol concentrations encountered in VAD. DESIGN: The stoichiometric relation between retinol and RBP was studied in 239 Marshallese children: 65 with severe VAD (< or = 0.35 micromol retinol/L), 94 with moderate VAD (0.36-0.70 micromol retinol/L), and 80 with vitamin A sufficiency (> 0.70 micromol retinol/L). RESULTS: Excellent correlation between retinol and RBP (r = 0.94) was observed across all retinol concentrations. Severe VAD was predicted with 96% sensitivity and 91% specificity on the basis of an RBP cutoff of < or = 0.48 micromol/L, whereas moderate VAD was predicted with 87% sensitivity and 98% specificity on the basis of an RBP cutoff of < or = 0.70 micromol/L. CONCLUSIONS: The use of RBP results in the classification of essentially the same children with VAD as does retinol, and RBP is an excellent surrogate for serum retinol. Considering the relative ease of measuring RBP with immunodiagnostic kits compared with that of serum retinol by HPLC, the use of RBP concentrations to assess VAD may be particularly advantageous in field settings. Consequently, measuring RBP concentrations may be a practical alternative to measuring serum retinol in population surveys assessing the prevalence of VAD.     

Retinol concentrations in capillary dried blood spots from healthy volunteers: method validation

BACKGROUND: Vitamin A deficiency (VAD) is a major public health problem in the developing world, leading to >3 million eye-related problems in preschool children. Nearly 250 million children have subclinical VAD, resulting in a 23% increase in childhood mortality. Difficulties in obtaining samples to assess VAD have hampered the detection, intervention, and surveillance of VAD. The use of dried blood spots (DBS) could ameliorate many problems of vitamin A assessment. OBJECTIVE: The objective of this study was to validate the use of retinol in DBS for vitamin A assessment by comparing it with venous and capillary serum retinol. DESIGN: Venous and capillary blood specimens were obtained simultaneously from 20 healthy adult volunteers. From each blood specimen, both DBS and liquid serum were prepared (a total of 80 samples). All specimens were maintained at -70 degrees C until HPLC analysis. RESULTS: The mean retinol concentrations in the 4 sample types were as follows: venous serum (2.02 +/- 0.42 micromol/L, or 58 +/- 12 microg/dL), capillary serum (2.06 +/- 0.42 micromol/L, or 59 +/- 12 microg/dL), venous DBS (2.06 +/- 0.49 micromol/L, or 59 +/- 14 microg/dL), and capillary DBS (2.09 +/- 0.45 micromol/L, or 60 +/- 13 microg/dL). Of the 6 possible 2-way combinations, the R(2) values ranged from 0.77 for capillary DBS versus venous DBS to 0.95 for venous serum versus capillary serum. CONCLUSIONS: DBS retinol measured by HPLC is comparable with serum retinol. Thus, it is possible to compare and combine blood retinol concentration data obtained from DBS with current and historic measurements in serum.     

Validation of a rapid enzyme immunoassay for the quantitation of retinol-binding protein to assess vitamin A status within populations

OBJECTIVE: To compare the prevalence of vitamin A deficiency (VAD) among Cambodian preschool children as determined by the retinol-binding protein-enzyme immunoassay (RBP-EIA) and direct measurement of serum retinol by high-performance liquid chromatography (HPLC). SETTING AND SUBJECTS: Sera from 359 children were randomly selected from archived specimens collected in a national VAD prevalence survey in Cambodia. METHODS: Sera were first analyzed for retinol content by HPLC and then subjected to analysis using RBP-EIA to determine serum RBP concentrations. National Institute of Standards and Technology and control sera were used to ensure quality and accuracy for each set of analyses. To classify VAD, the same cutoff point of <0.70 micromol/l was employed for each indicator. RESULTS: Overall, the prevalence of VAD based on serum retinol was 22.3% (95% confidence interval (CI): 18.0, 26.6), whereas the RBP-EIA indicated a VAD prevalence of 20.9% (95% CI: 16.7, 25.1). A simple linear regression model indicated an R2 of 0.79, and a receiver operating curve analysis revealed an area under the curve of 0.92. CONCLUSIONS: We found no significant difference between the results of RBP-EIA compared to retinol analyzed by HPLC in estimating the prevalence of VAD. Use of the test could enable public health authorities to assess the extent of VAD and track progress in control programs in resource-poor settings.     

Prevalence and factors associated with vitamin A deficiency in preschool children from Teresina, Piauí, Brazil

Vitamin A deficiency is a public health problem in the Northeast of Brazil. This study aimed to determine the prevalence of vitamin A deficiency and associated factors among preschool children in Teresina, Piauí, Brazil. We studied the serum retinol levels and socioeconomic and demographic characteristics of 631 children from 36 to 83 months of age. The statistical association between each of the above characteristics and serum retinol levels was investigated by univariate and multivariate linear regression analysis. Mean serum retinol was 1.21 mmol/L (95%CI: 1.17-1.25 micromol/L) and was independent of gender (p = 0.259). Prevalence of vitamin A deficiency (retinol < 0.69 micromol/L) was 15.4% (95%CI: 12.7-18.4), with a tendency to decrease with age. Acceptable but not adequate retinol levels (0.70 to 1.04 micromol/L) were observed in 29% of children (95%CI: 25.2-32.4). There were positive associations between retinol levels and age, income, vitamin A supplementation, and maternal schooling. Vitamin A deficiency appeared as a moderately serious public health problem, emphasizing the importance of strategies to combat this problem in the region.     

Vitamin A deficiency in patients with diarrhea and HIV infection in Ethiopia

Diarrhea, micronutrient deficiencies and HIV/AIDS are major public health problems in developing countries, especially in sub-Saharan Africa. This study was aimed to investigate serum levels of vitamin A in diarrheic patients with and without HIV co-infection compared to healthy controls. Two hundred eleven diarrheic patients (110 HIV infected), 87 apparently healthy controls and 41 asymptomatic HIV seropositive blood donors who visited the University of Gondar Hospital, in Gondar, Ethiopia were included. Stool samples were examined for enteropathogens following the standard procedures. Serum vitamin A levels were measured by high performance liquid chromatography. Shigella species were isolated from 8.5% of the patients while intestinal parasites were detected in 32.2% without significant difference by HIV serostatus. The mean+/-SD serum vitamin A in diarrheic patients with (0.82+/-0.59 micromol/L) and without (0.84+/-0.54 micromol/L) HIV co-infection and in asymptomatic HIV infected blood donors (0.96+/-0.52 micromol/L) was significantly lower than that in healthy controls (1.52+/-0.71 micromol/L), p<0.001. Vitamin A deficiency (VAD, serum retinol < 0.70 micromol/L) was observed in 52.7% and 45.5% of diarrheic patients with and without HIV co-infection, respectively. About 13% of healthy controls and 29.3% of asymptomatic HIV infected blood donors were deficient in vitamin A. The levels of serum vitamin A were not associated with the presence of intestinal parasites or Shigella species. The findings demonstrate that VAD is a severe public health problem among diarrheic patients in Gondar, Ethiopia. Intervention programmes involving health and nutrition education and supplementation of vitamin A might help in reducing morbidity in such patients.     

Detection of vitamin A deficiency in Brazilian preschool children using the serum 30-day dose-response test

BACKGROUND: Vitamin A deficiency (VAD) is endemic in Brazil and health professionals have difficulty in recognizing its subclinical form. In addition, serum retinol concentrations do not always represent vitamin A status in the organism. OBJECTIVE: To identify VAD in preschool children by the serum 30-day dose-response test (+S30DR) and to examine its potential as a tool for the assessment of vitamin A status in the community. DESIGN: A prospective transverse study in which blood samples were obtained from 188 preschool children for the determination of serum retinol concentrations and the children were submitted to ocular inspection and anthropometric measurements. Information about the presence of diarrhea and/or fever during the 15 days preceding the study was also obtained. The children received an oral dose of 200,000 IU vitamin A immediately after the first blood collection. A second blood sample was obtained 30-45 days after supplementation in order to determine the +S30DR. RESULTS: In all, 74.5% (140/188; 95% confidence interval: 68.3-80.7%) of the children presented +S30DR values indicative of low hepatic reserves. The mean serum retinol concentration was significantly lower before supplementation (0.92 and 1.65 micromol/l, respectively; P < 0.0001). No child presented xerophthalmia; 3.7% (7/188) of the children were malnourished. The presence of fever and/or diarrhea during the 15 days preceding the first blood collection did not affect the +S30DR value. CONCLUSIONS: The prevalence of VAD in the study group was elevated. +S30DR proved to be a good indicator of subclinical VAD in children from an underdeveloped country.     

Carotenoid status among preschool children with vitamin A deficiency in the Republic of the Marshall Islands

Although carotenoids are known to be important dietary sources of vitamin A, there have been few epidemiological studies that have characterized the serum concentrations of major dietary carotenoids among preschool children with vitamin A deficiency. We conducted a population-based, cross-sectional study of serum pro-vitamin A carotenoids (alpha -carotene, beta-carotene, beta-cryptoxanthin), non-provitamin A carotenoids (lutein/zeaxanthin, and lycopene), and retinol among 278 children, aged 1-5 y, in the Republic of the Marshall Islands. Vitamin A deficiency was defined as serum retinol <0.70 micromol/L. Geometric mean serum concentrations of carotenoids among children with and without vitamin A deficiency were 0.003 vs 0.006 micromol/L for alpha-carotene (P = 0.0017), 0.011 vs 0.023 micromol/L for beta-carotene (P <0.0001), 0.023 vs 0.034 micromol/L for beta-cryptoxanthin (P = 0.0075), 0.007 vs 0.012 micromol/L for lycopene (P = 0.037), 0.044 vs 0.052 micromol/L for lutein/zeaxanthin (P = 0.2), and 0.045 vs 0.074 micromol/L for total provitamin A carotenoids (P <0.0001) respectively. In a multivariate analysis adjusting for sex, age (Odds Ratio [O.R.] 1.44, 95% confidence interval [C.I.] 1.16-1.78), and serum provitamin A carotenoids (O.R. 0.49, 95% C.I. 0.34-0.71) were associated with vitamin A deficiency, but serum non-provitamin A carotenoids were not associated with vitamin A deficiency (O.R. 0.93, 95% C.I. 0.67-1.28). Preschool children with vitamin A deficiency in the Republic of the Marshall Islands have extremely low serum concentrations of provitamin A carotenoids and interventions are needed to improve the dietary intake of provitamin A carotenoids among Marshallese children.     

Serum retinol distributions in residents of the United States: third National Health and Nutrition Examination Survey, 1988-1994

BACKGROUND: Inadequate vitamin A status has been a potential nutritional problem for some segments of the US population, particularly children and the poor. OBJECTIVE: We evaluated serum retinol concentration by using population-representative data from 16058 participants aged 4 to >/=90 y in the third National Health and Nutrition Examination Survey, 1988-1994. DESIGN: We used multivariate regression to examine the simultaneous associations of sociodemographic, biologic, and behavioral factors with serum retinol concentration. RESULTS: In children, serum retinol concentrations were greater with greater age, body mass index, serum lipids, and the use of supplements containing vitamin A. In adults, male sex, serum lipids, alcohol consumption, and age were positively associated with serum retinol concentration in most racial/ethnic strata. Household income was not associated with serum retinol concentration in children; associations were inconsistent in adults. The prevalence of serum retinol <0.70 micromol/L was very low in all strata; the prevalence of serum retinol <1.05 micromol/L was 16.7-33.9% in children aged 4-8 y and 3.6-14.2% in children aged 9-13 y, depending on sex and racial/ethnic group. The prevalence of serum retinol<1.05 micromol/L was higher in non-Hispanic black and Mexican American children than in non-Hispanic white children; these differences remained significant (P < 0.0001) after covariates were controlled for. Among adults, nonwhite women were significantly (P < 0.0001) more likely than white women to have serum retinol <1.05 micromol/L after covariates were controlled for. CONCLUSIONS: Clinically low serum retinol concentration is uncommon in US residents aged > or = 4 y, although racial/ethnic and socioeconomic differences in serum retinol concentration still exist.     

Vitamin A deficiency and anemia among children 12-71 months old in Honduras.

Vitamin A deficiency (VAD) and iron deficiency anemia (IDA) have been recognized as public health problems in Honduras for over 30 years. This paper, based on the 1996 National Micronutrient Survey on 1678 children 12-71 months of age, presents the results for vitamin A status and anemia prevalence, as well as the level of vitamin A in sugar at the household level. The results showed that 14% of the children were subclinically vitamin A deficient (plasma retinol < 20 micrograms/dL) and 32% were at risk of VAD (plasma retinol 20-30 micrograms/dL). These data indicate that VAD is a moderate public health problem in Honduras. Logistic regression analysis showed that children 12-23 months old living in areas other than the rural south of the country were at greatest risk of subclinical VAD. Infection, indicated by an elevated alpha-1-acid-glycoprotein level, increased the risk of subclinical VAD more than three-fold. Children from households that obtained water from a river, stream, or lake were at twice the risk of subclinical VAD compared with other children. That same doubled risk was found for children from a household with an outside toilet. VAD can be controlled by fortifying sugar. Retinol levels in sugar at the household level were about 50% of those mandated by Honduran law. There appears to be significant leakage of unfortified sugar into the market. This is particularly true in the rural north, where 33% of samples contained no retinol. Overall, 30% of children were anemic (Hb < 11 g/dL). Logistic regression analysis showed that children whose fathers lived with them but who had not attended at least grade 4 of primary school were at 33% greater risk of being anemic. Infection and being underweight increased the risk of being anemic by 51% and 21%, respectively. Many of the anemic children had not been given iron supplements, suggesting health care providers may not be aware that anemia is widespread among young children and/or know how to diagnose it.     

Iron and vitamin A deficiency in long-term African refugees

Five cross-sectional surveys were conducted in African refugee camps to assess the level of iron deficiency anemia and vitamin A deficiency in populations dependent on long-term international food aid and humanitarian assistance. The prevalence of anemia in children [hemoglobin (Hb) <110 g/L] was high, with >60% affected in 3 of 5 camps. Iron deficiency [serum transferrin receptor (sTfR) >8.5 mg/L] was also high, ranging from 23 to 75%; there was also a strong ecological correlation between the prevalence of iron deficiency and anemia among different camps. Within camps, sTfR predicted the concentration of Hb with adjusted R(2) values ranging from 0.19 to 0.51. Although children were more affected, anemia was also a public health problem in adolescents and women. The effect of recent recommendations on Hb cutoff values for African populations was assessed and found to produce decreases in the prevalence of anemia of between 5 and 21%; this did not affect the public health categorization of the anemia problem within the most affected camps. Mean serum retinol in children, after adjustment for infection status, ranged from 0.72 +/- 0.2 to 0.88 +/- 0.2 micromol/L in the 4 camps assessed and vitamin A deficiency (<0.7 micromol/L) was present at levels ranging from 20.5 to 61.7%. In areas in which vitamin A capsule distribution programs were in effect, coverage ranged from 3.5 up to 66.2%. The high level of micronutrient deficiencies seen in long-term refugees argues in favor of further enhancements in food aid fortification and the strengthening of nutrition and public health programs.     

Co-existence of anemia, vitamin A deficiency and growth retardation among children 24-84 months old in Maracaibo, Venezuela

Iron deficiency anemia has been associated with alterations in child development and psychomotor function, being myelination and dopaminergic functioning especially vulnerable. Iron deficiency, at different ages, has different reversible and irreversible effects on CNS. Anemia has also been related to vitamin A deficiency (VAD) and growth retardation. The aim of the present paper was to determine the coexistence of micronutrient deficiency, iron and vitamin A, and macronutrient deficiency (growth retardation). The sample consisted of 202 Venezuelan children, aged 24-84 month old, (104 girls, 98 boys); Anemia, VAD and growth retardation was evaluated by means of blood hemoglobin concentration analysis, HPLC serum retinol (values <20 microg/dl reveal VAD) and height/age and weight/age Z scores (< or = - 2 SD express stunting and underweight). Prevalence of anemia was 38.11%; VAD, 21.78%; stunting, 14.36% and underweight, 9.40%. Anemia and VAD clustered in 7.92%; anemia + stunting or + underweight coexisted in 5.94% and 2.97%, respectively. Stunting and underweight clustered with VAD in 2.97% and 1.48%. The three-way combination with anemia was only seen with stunting in 0.99% of the sample. The prevalence of micronutrient deficiencies remain as significant public health problems which should be simultaneously treated as virtually independent, giving priority to infant, toddler and preschool age groups.     

Prevalence of hypovitaminosis A among preschool children from northeastern Brazil, 1998

OBJECTIVE: To determine the prevalence of vitamin A deficiency in a population-based sample. METHODS: This was a cross-sectional study conducted in the State of Sergipe, northeastern Brazil, in May and June, 1998. It involved 607 children aged 6 to 60 months. The information was obtained by means of interviews with the persons responsible for these children, in their homes. Blood samples were collected via venous puncture and serum retinol assays were carried out by means of high performance liquid chromatography (HPLC). In simultaneous analyses of the study variables, p<0.05 was accepted for testing statistically significant associations. RESULTS: A mean serum retinol value of 0.87 micromol/l (+/- 0.38) was found among the children investigated. The prevalence of levels considered low (0.35 to 0.69 micromol/l) was 22.5% and the prevalence of levels considered deficient (<0.35 micromol/l) was 9.6%. Inadequate serum retinol levels were therefore seen in 32.1% of the children. The serum retinol level showed an association with per capita family income and the weight/age indicator. No statistically significant association was found for serum retinol level in relation to the child's age and sex, or the mother's variables. CONCLUSION: Vitamin A deficiency among preschool children is an important public health problem. Hypovitaminosis A is mainly related to low per capita family income and low infant weight.     

Endemic goiter with iodine sufficiency: a possible role for the consumption of pearl millet in the etiology of endemic goiter

BACKGROUND: Deficiencies of iodine, iron, and vitamin A are the 3 most common micronutrient deficiencies in developing countries, although control programs, when properly implemented, can be effective. OBJECTIVE: We investigated these deficiencies and their possible interaction in preschool children in the southern Blue Nile area of Sudan. DESIGN: Goiter, signs of vitamin A deficiency, and biochemical markers of thyroid, vitamin A, and iron status were assessed in 984 children aged 1-6 y. RESULTS: The goiter rate was 22. 3%. The median urinary iodine concentration was 0.79 micromol/L and 19.3% of the children had a concentration >1.57 micromol/L. Although serum thyroxine and triiodothyronine concentrations were within reference ranges, the median thyrotropin concentration was 3.78 mIU/L and 44% of the children had thyrotropin concentrations above normal. The mean urinary thiocyanate concentration was high (259 +/- 121 micromol/L). The prevalences of Bitot spots and night blindness were 2.94% and 2.64%, respectively, and 32% of the subjects had serum retinol binding protein concentrations <15 mg/L. A significant positive correlation was observed between thyrotropin and retinol binding protein. Whereas 88% of the children had hemoglobin concentrations <1.86 mmol/L, only 13.5% had serum ferritin concentrations below the cutoff of 12 microg/L and 95% had serum transferrin concentrations above the cutoff of 2.50 g/L. CONCLUSIONS: Our results indicate that goiter is endemic in this region of Sudan despite iodine sufficiency and that both anemia and vitamin A deficiency are health problems in the area. Moreover, consumption of millet, vitamin A deficiency, and protein-energy malnutrition are possible etiologic factors in this endemic area.     

西藏自治区六岁以下儿童维生素A缺乏情况调查

目的 了解西藏自治区6岁以下儿童维生素A缺乏(VAD)情况。方法 采用分层整群随机抽样方法,将西藏分为城市、牧业县、农业县、半农半牧县4层,每层抽2个市或县进行调查。调查内容包括家庭一般状况、儿童喂养和疾病情况,收集儿童血清。血清维生素A(VA)含量检测采用微量荧光法。结果 共调查6岁以下儿童1257人,男635人,女622人,藏族占98．8％。2岁以上儿童836人,发现儿童夜盲症6例,结膜干燥症2例,儿童临床VAD患病率为0．96％。在1071名接受调查的母亲中,夜盲症18例(1．7％)。4类地区均发现有临床VAD病例。西藏儿童VA平均水平为1．09μmol／L,城市儿童(1．15μmol／L)和牧业县儿童(1．12μmol／L)显著高于农业县儿童(1．04μmol／L)和半农半牧县儿童(1．05μmol／L)。儿童亚临床VAD(血清VA≤0．70μmol／L)患病率：城市、牧业县、农业县和半农半牧县儿童分别为5．4％、4．7％、11．0％和12．3％,差异有显著性;0．5岁以下和0．5岁以上婴儿组亚临床VAD患病率分别为22．2％和13．3％,显著高于1岁以上各年龄组儿童(1岁为8．5％,2～3岁为5．4％,4～5岁为7．9％);男女儿童血清VA水平和亚临床VAD患病率的差异无显著性。结论 西藏儿童VAD情况较全国为轻,但农业县和半农半牧县属于中度亚临床VAD地区,需要对这些地区的儿童,特别是1岁以下的婴儿补充VA。     

Vitamin A deficiency and low prevalence of anemia in Yaqui Indian children in northwest Mexico

A study of 296 school-age Yaqui Indian children (6-10 y) was conducted in 26 rural communities. Vitamin A status was determined by retinol and carotenoid serum levels according to a method described previously (IVACG, 1982). Serum retinol and carotenoids in children were analyzed according to community size. Vitamin A intake was assessed in a sub-sample by means of a 24 h recall questionnaire. Serum retinol distribution showed that 6.3% of the children were below 10 microg/100 mL (0.35 micromol/L) and 40% were in the range of 10-20 microg/100 mL (0.35-0.70 micromol/L). Differences (p < 0.02) were found between small and large communities (Median, 95% CI): 19.2 (17.1, 20.9) microg/100 mL and 22.9 (20.3, 24.1) microg/100 mL. Serum carotenoid levels were significantly higher in large than in small and medium communities: 72 (68.2, 77.8) microg/100 mL versus 62.4 (53.3, 68.2) and 62.4 (55.7, 69.6) microg/100 mL, respectively. Food staples were wheat flour tortillas, pinto beans, corn tortillas, few animal products and scarce fresh vegetables. Mean vitamin A consumption was 244+/-29 microg RE (34.9% of the US RDA). Iron status showed that only 4 children were classified as anemic, with two of them having iron deficiency anemia. Iron deficient erythropoiesis was observed in 7.8% of the children and iron depletion only in 4.4%. The Yaqui diet seems to provide adequate amounts of iron but not of vitamin A or its precursors, which renders a vitamin A status of sub-clinical deficiency that could be considered a public health problem.     

Synergistic effect of zinc and vitamin A on the biochemical indexes of vitamin A nutrition in children.

BACKGROUND: Zinc deficiency limits the bioavailability of vitamin A. Because zinc and vitamin A deficiency often coexist in malnourished children, simultaneous zinc and vitamin A supplementation may improve the vitamin A deficiency in these children. OBJECTIVE: A randomized, double-blind, placebo-controlled intervention trial was conducted to evaluate whether combining zinc and vitamin A supplementation would improve the biochemical indexes of vitamin A nutriture. DESIGN: Children aged 12-35 mo were randomly assigned to 1 of 4 intervention groups: 20 mg Zn/d for 14 d (Z group), 60000 retinol equivalents (200000 IU) vitamin A on day 14 (A group), zinc plus vitamin A (ZA group), or placebo syrup and placebo capsule (placebo group). Venous blood was drawn at enrollment and on day 21. RESULTS: Mean serum retinol concentrations were not significantly different between the A and ZA groups. Among vitamin A-deficient children, the proportion of children who remained vitamin A deficient (serum retinol <0.7 micromol/L) after supplementation was 40.6% in the Z group, 37.5% in the A group, and 47.0% in the placebo group; only 13.3% in the ZA group remained vitamin A deficient (P < 0.05 compared with the placebo group). The proportion of children whose retinol binding protein concentrations remained low was significantly lower in the ZA group than in the other groups (P < 0.05). CONCLUSION: Combined zinc and vitamin A supplementation improves vitamin A nutriture in vitamin A-deficient children.     

Effects on serum retinol of multi-micronutrient supplementation and multi-helminth chemotherapy: a randomised,controlled trial in Kenyan school children

OBJECTIVE: To assess the effects of multi-micronutrient supplementation and multi-helminth chemotherapy on serum retinol concentration, using schools as a health delivery system. STUDY AREA AND POPULATION: From 19 primary schools in Bondo District, western Kenya, 977 children between 9 and 18 y were included in the trial. The 644 (65.9%) children on whom baseline serum retinol was available were included in this study. DESIGN: A randomised, placebo-controlled, double-blind, two-by-two factorial trial on the effects of multi-micronutrient supplementation and multi-helminth chemotherapy on serum retinol after 8 months. INTERVENTION: Single treatment with albendazole (600 mg) and praziquantel (40 mg/kg of body weight) and daily multi-micronutrient supplementation with tablet containing 1000 microg vitamin A. RESULTS: Micronutrient supplementation (0.08 micromol/l, 95% CI 0.01, 0.14; P=0.025), but not treatment (0.03 micromol/l, 95% CI -0.04, 0.10; P=0.38), increased serum retinol. However, treatment did increase serum retinol in S. mansoni-infected (0.09, 95% CI 0.02, 0.16; P=0.009), but not in uninfected children (-0.07, 95% CI -0.18, 0.03; P=0.18; interaction, P=0.01). Similarly, reduction in egg output of S. mansoni, but none of the geohelminth, was a predictor, corresponding to a 0.008 micromol/l (95% CI 0.00002, 0.02; P=0.049) increase in serum retinol per 100 epg reduction. Interestingly, interactions were found between age and sex (P=0.046), and malaria parasitaemia and sickle cell phenotype (P=0.04). CONCLUSION: Multi-micronutrient supplementation and reduction in S. mansoni egg output increased serum retinol, irrespective of initial serum retinol. SPONSORSHIP: The Danish International Development Assistance.     

Co-existing micronutrient deficiencies among stunted Cambodian infants and toddlers

The prevalence of malnutrition in Cambodia is among the highest in Southeast Asia, and diarrhea and pneumonia are the leading causes of death among children. Whether these adverse health outcomes are associated with co-existing micronutrient deficiencies is uncertain. We have determined the prevalence of anaemia, as well as iron, zinc, and vitamin A deficiency and their co-existence among stunted children (77 females; 110 males) aged 6-36 mos. Non-fasting morning venipuncture blood samples were taken and analyzed for haemoglobin (Hb), serum ferritin (via IMx system), retinol (via HPLC), and Zn (via AAS), C-reactive protein (CRP) (via turbidimetry) and Hb type (AA, AE, or EE) (via Hb gel electrophoresis). Children with CRP>or=5.0 mg/L (n=34) were excluded. Zinc deficiency defined as serum Zn<9.9 micromol/L had the highest prevalence (73.2%), followed by anaemia (71%) (Hb<110 g/L), and then vitamin A deficiency (28.4%) (serum retinol<0.70 micromol/L). Of the anaemic children, only 21% had iron deficiency anaemia, and 6% had depleted iron stores. Age, log serum ferritin, and Hb type were significant predictors of Hb in the AA and AE children. Serum retinol was unrelated to haemoglobin or serum zinc. The prevalence of two or more micronutrient deficiencies (low Hb, serum retinol, and/or serum zinc) was 44%. Nearly 10% had low values for all three indices, and 18% had just one low value. In conclusion, anaemia, and deficiencies of iron, zinc, and vitamin A are severe public health problems among these stunted Cambodian children. Intervention strategies addressing multiple micronutrient deficiencies are needed.     

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.     

A food-based approach introducing orange-fleshed sweet potatoes increased vitamin A intake and serum retinol concentrations in young children in rural Mozambique

Vitamin A deficiency is widespread and has severe consequences for young children in the developing world. Food-based approaches may be an appropriate and sustainable complement to supplementation programs. Orange-fleshed sweet potato (OFSP) is rich in beta-carotene and is well accepted by young children. In an extremely resource poor area in Mozambique, the effectiveness of introduction of OFSP was assessed in an integrated agriculture and nutrition intervention, which aimed to increase vitamin A intake and serum retinol concentrations in young children. The 2-y quasi-experimental intervention study followed households and children (n = 741; mean age 13 mo at baseline) through 2 agricultural cycles. In y 2, 90% of intervention households produced OFSP, and mean OFSP plot size in intervention areas increased from 33 to 359 m(2). Intervention children (n = 498) were more likely than control children (n = 243) to eat OFSP 3 or more d in the last wk (55% vs. 8%, P < 0.001) and their vitamin A intakes were much higher than those of control children (median 426 vs. 56 microg retinol activity equivalent, P < 0.001). Controlling for infection/inflammation and other confounders, mean serum retinol increased by 0.100 micromol/L (SEM 0.024; P < 0.001) in intervention children and did not increase significantly in control subjects. Integrated promotion of OFSP can complement other approaches and contribute to increases in vitamin A intake and serum retinol concentrations in young children in rural Mozambique and similar areas in Sub-Saharan Africa.