Mild vitamin A deficiency and risk of respiratory tract diseases and diarrhea in preschool and school children in northeastern Thailand

Effects of primary or secondary prevention with vitamin A supplementation on clinically important outcomes: a systematic review of randomised clinical trials with meta-analysis and trial sequential analysis

OBJECTIVES

This systematic review with meta-analyses of randomised trials evaluated the preventive effects of vitamin A supplements versus placebo or no intervention on clinically important outcomes, in people of any age.

METHODS

We searched different electronic databases and other resources for randomised clinical trials that had compared vitamin A supplements versus placebo or no intervention (last search 16 April 2024). We used Cochrane methodology. We used the random-effects model to calculate risk ratios (RRs), with 95% CIs. We analysed individually and cluster randomised trials separately. Our primary outcomes were mortality, adverse events and quality of life. We assessed risks of bias in the trials and used Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) to assess the certainty of the evidence.

RESULTS

We included 120 randomised trials (1 671 672 participants); 105 trials allocated individuals and 15 allocated clusters. 92 trials included children (78 individually; 14 cluster randomised) and 28 adults (27 individually; 1 cluster randomised). 14/105 individually randomised trials (13%) and none of the cluster randomised trials were at overall low risk of bias. Vitamin A did not reduce mortality in individually randomised trials (RR 0.99, 95% CI 0.93 to 1.05; I²=32%; p=0.19; 105 trials; moderate certainty), and this effect was not affected by the risk of bias. In individually randomised trials, vitamin A had no effect on mortality in children (RR 0.96, 95% CI 0.88 to 1.04; I²=24%; p=0.28; 78 trials, 178 094 participants) nor in adults (RR 1.04, 95% CI 0.97 to 1.13; I²=24%; p=0.27; 27 trials, 61 880 participants). Vitamin A reduced mortality in the cluster randomised trials (0.84, 95% CI 0.76 to 0.93; I²=66%; p=0.0008; 15 trials, 14 in children and 1 in adults; 364 343 participants; very low certainty). No trial reported serious adverse events or quality of life. Vitamin A slightly increased bulging fontanelle of neonates and infants. We are uncertain whether vitamin A influences blindness under the conditions examined.

CONCLUSIONS

Based on moderate certainty of evidence, vitamin A had no effect on mortality in the individually randomised trials. Very low certainty evidence obtained from cluster randomised trials suggested a beneficial effect of vitamin A on mortality. If preventive vitamin A programmes are to be continued, supporting evidence should come from randomised trials allocating individuals and assessing patient-meaningful outcomes.

PROSPERO REGISTRATION NUMBER

CRD42018104347.

Association between infection and nutritional status among infants in a cohort study of vitamin A in western Kenya

Background

Infection is associated with impaired nutritional status, especially for infants younger than 5 years.

Objectives

We assessed the impact of infection indicated by both acute phase proteins (APP), C-reactive protein (CRP), and α-1-acid-glycoprotein (AGP), and as reported by maternal recall on the nutritional status of infants.

Materials and methods

A total of 505 pregnant women were enrolled in a nested longitudinal cohort study of vitamin A (VA). Data from 385 children are reported here. The incidence and severity of respiratory infection and diarrhea (previous 14 days) were assessed by maternal recall; infant/child feeding practices were collected. Infant weight, recumbent length, and heel-prick capillary blood were taken at 9 months postpartum. Indicators of the VA status [retinol binding protein (RBP)], iron status (Hb, ferritin), and subclinical inflammation APP, CRP (>5 mg/L), and AGP (>1 g/L) were determined. Impacts of infection on the infant nutritional status were estimated using logistic regression models.

Results

Infection prevalence, based on elevated CRP and AGP levels, was 36.7%. For diarrhea reported symptoms, 42.4% of infants at 9 months had no indication of infection as indicated by CRP and AGP; for acute respiratory reported symptoms, 42.6% had no indication of infection. There was a significant positive association with infection among VA-deficient (RBP < 0.83 μmol/L) infants based on maternal reported symptoms but not with iron deficiency (ferritin < 12 μg/L). The odds of having infection, based on increased CRP and AGP, in underweight infants was 3.7 times higher (OR: 3.7; 95% CI: 2.3, 4.5; P = 0.019). Infants with iron deficiency were less likely (OR: 0.40; 95% CI: 0.1, 0.7; P = 0.001) to have infection based on CRP and AGP, while infants with VA deficiency were five times more likely (OR: 5.06; 95% CI: 3.2, 7.1; P = 0.0001) to have infection.

Conclusion

Acute phase proteins are more useful in defining infection in a population than reported symptoms of illness. Not controlling for inflammation in a population while assessing the nutritional status might result in inaccurate prevalence estimation.

Association of lower vitamin a levels in neonates and their mothers with increased risk of neonatal late-onset sepsis: A case-control study

BACKGROUND

In developing countries, neonatal sepsis is one of the major causes of mortality and morbidity. Vitamin A deficiency also affects the immune system severely and is associated with various neonatal infections. We aimed to compare maternal and neonatal vitamin A levels among neonates with and without late-onset sepsis.

MATERIAL AND METHODS

40 eligible infants were entered into this case-control study according to inclusion criteria. The case group included 20 term or near-term infants who had late-onset neonatal sepsis from three to seven days of life. The control group consisted of 20 term or near-term infants who were icteric hospitalized neonates without sepsis. Demographic, clinical and paraclinical features, as well as neonatal and maternal vitamin A levels, were compared between the two groups.

RESULTS

The average gestational age of the neonates was 37.1 ± 1.2, ranging from 35 to 39 days. There was a significant difference between the septic and non-septic groups in terms of white blood cell and neutrophil count, C-reactive protein, and neonatal and maternal vitamin A levels. A Spearman correlation analysis showed a significant direct correlation among maternal and neonatal vitamin A levels (correlation coefficient = 0.507; P-value = 0.001). Multivariate regression analysis showed that neonates' vitamin A level had a significant direct association with sepsis (OR: 0.541; P-value=0.017).

CONCLUSION

Our findings demonstrated the association of lower vitamin A levels in neonates and their mothers with an increased risk of late-onset sepsis, which emphasizes the importance of the consideration of vitamin A level evaluation and its appropriate neonatal and maternal supplementation.

Serum Inflammatory Cytokines and Vitamin A in Nigerian Children with Community-Acquired Pneumonia: Association with Severity and Outcome

Objective Pneumonia is an acute inflammation of the lung parenchyma caused by microbial agents. The role of inflammatory mediators and modulators like vitamin A in childhood pneumonia in developing countries is poorly explored. The aim of this study is to determine the relationship between serum vitamin A and inflammatory cytokines (i.e., proinflammatory interleukins [IL]-1β, -2, -3, -6, -8, -12, and -17 and anti-inflammatory IL-4, -10, -11, and -13) in Nigerian children with community-acquired pneumonia (CAP) and relate these to pneumonia severity and length of hospital stay (LOS).

Methods Children aged 2 months to 14 years with World Health Organization (WHO) defined CAP and age and sex-matched controls were recruited over a 12-month period. Relevant data, serum cytokines, and vitamin A (assayed using chromatography method) were compared between the two groups, and between those with severe and nonsevere pneumonia. Relationships between serum vitamin A, cytokines, and LOS were also determined.

Results One hundred and thirty-two children (66 each for CAP and controls; M: F = 1.8:1) were recruited and 17 (12.9%) were vitamin-A deficient. Of the 66 with CAP, 52 (78.8%) had severe pneumonia. Serum proinflammatory cytokines (IL-6, -8, -12, and -17) and anti-inflammatory cytokines (IL-4 and -11) were higher in children with CAP compared with controls. In under-five age group, lower serum IL-4 and vitamin A were associated with severe CAP. Vitamin-A deficient children with CAP had lower proinflammatory cytokines (IL-1β, IL-2, -3, -12, and -17) and anti-inflammatory cytokine IL-4 than vitamin A sufficient ones. IL-6 and IL-8 correlated positively with LOS.

Conclusion CAP is associated with elevated serum proinflammatory cytokines and possible resultant higher need of antioxidants properties of vitamin A in severe cases. Vitamin A may be more important to ameliorate the acute inflammatory processes in Nigerian children with severe than nonsevere pneumonia.

Vitamin A deficiency in critically ill children with sepsis

BACKGROUND

Data that indicate vitamin A status in critically ill children with sepsis are sparse. The association between serum vitamin A levels and the clinical outcomes of sepsis has not been well assessed. The aim of this study was to assess the prevalence of vitamin A deficiency in critically ill children with sepsis and its association with clinical outcomes.

METHODS

Critically ill children with sepsis admitted to the pediatric intensive care unit were engaged in this prospective study. Sex- and age-matched approximate-health children from the Department of Pediatric Surgery were enrolled as the control group. Blood samples were collected from all patients in the first 24 h of admission for the measurement of serum vitamin A status. We compared vitamin A status between the sepsis group and the control group. In addition, we compared the clinical characteristics of the two subgroups of septic patients with vitamin A deficiency and those without vitamin A deficiency. Univariate and multivariable methods were used to evaluate the association between vitamin A deficiency and septic shock.

RESULTS

One hundred sixty septic children and 49 approximate-health children were enrolled in this study. Vitamin A deficiency was found in 94 (58.8%) subjects in the study group and 6 (12.2%) subjects in the control group (P < 0.001). In septic patients, 28-day mortality and hospital mortality in patients with vitamin A deficiency were not significantly higher than that in patients without vitamin A deficiency (P > 0.05). However, vitamin A levels were inversely associated with higher PRISM scores in septic children with VAD (r = - 0.260, P = 0.012). Vitamin A deficiency was associated with septic shock with an unadjusted odds ratio (OR) of 3.297 (95% confidence interval (CI), 1.169 to 9.300; P = 0.024). In a logistic model, vitamin A deficiency (OR, 4.630; 95% CI, 1.027-20.866; P = 0.046), procalcitonin (OR, 1.029; 95% CI, 1.009-1.048; P = 0.003), and the Pediatric Risk of Mortality scores (OR, 1.132; 95% CI, 1.009-1.228; P = 0.003) were independently associated with septic shock.

CONCLUSION

The prevalence of vitamin A deficiency was high in children with sepsis. Vitamin A deficiency may be a marker of mortality in critically ill children with sepsis.

TRIAL REGISTRATION

Clinicaltrials.gov , NCT03598127.

Dietary Vitamin-a Deficiency: Effects on Growth, Infection, and Mortality

Vitamin A (VA) has been experimentally linked in animals to growth in weight, host resistance to infection, and survival for nearly eight decades. These consistent findings appear to have their human correlate. VA-deficient children are more likely to have comorbidity and to be stunted in growth, and they have a higher risk of mortality. In several large field trials VA supplementation has reduced mortality by >= 30%. Presumably a similar or greater public health impact can be achieved by improving dietary VA intake. The relation between dietary imbalance and VA deficiency starts at a young age. Early cessation of breast-feeding, poor quality of the weaning diet, and infrequent consumption of VA-rich foods appear to underlie mild xerophthalmia. These dietary imbalances often coexist with food access. We must know how to alter detrimental food habits before dietary interventions can be formulated. Improving dietary quality to enhance VA nutriture will likely carry numerous other nutritional benefits to children.

The effect of neonatal vitamin A supplementation on morbidity and mortality at 12 months: a randomized trial

Background: Neonatal vitamin A supplementation (NVAS) is an intervention hypothesized to reduce infant morbidity and mortality. The objective of this study was to assess the efficacy of neonatal vitamin A supplementation in reducing infant morbidity and mortality and assess potential sources of heterogeneity of the effect of NVAS.

Methods: We completed an individually randomized, double-blind, placebo-controlled trial in Tanzania. Infants were randomized within 3 days of birth to a single dose of vitamin A (50 000 IU) or placebo. We assessed infants at 1 and 3 days after supplementation, as well as 1, 3, 6 and 12 months after supplementation. We included all live births in the analysis and used relative risks (RR) and 95% confidence intervals (CI) to assess the risks of mortality and hospitalization by 12 months. We used general estimating equations to assess the incidence of morbidities during infancy.

Results: A total of 31 999 infants were enrolled in the study between August 2010 and March 2013. At 12 months, vitamin A did not reduce all-cause infant mortality (RR 1.04; 95% CI 0.92-1.16), nor affect hospitalization (RR 1.09; 95% CI 0.97-1.22) or all-cause morbidity (RR 1.00; 95% CI 0.96-1.05). Postpartum maternal vitamin A supplementation modified the effect of neonatal vitamin A supplementation on mortality at 12 months (P-value, test for interaction = 0.04). Among infants born to women who received a mega-dose of vitamin A after delivery, NVAS appeared to increase the risk of death (RR 1.12; 95% CI 0.98-1.29), whereas the risk of death among infants born to women who did not receive a mega-dose was reduced (RR 0.86; 95% CI 0.70-1.06). We noted no modification of the effect of NVAS by infant gender, birthweight or maternal HIV status.

Conclusion: NVAS did not affect the risk of death or incidence of common childhood morbidities. However, this study sheds light on potential sources of heterogeneity of the effect of neonatal vitamin A supplementation which should be further examined in a pooled analysis of all NVAS trials.

Nutritional Potential of Red Palm Oil for Combating Vitamin A Deficiency

Although the severe vitamin A deficiency responsible for ocular damage is now rare, subclinical vitamin A deficiency still contributes importantly to high child mortality in the developing countries of Asia. This demands urgent and effective preventive action. Although periodic large doses of vitamin A for this purpose have been a favoured approach of international agencies, the coverage achieved has been inadequate and is usually not sustainable without external support. for this reason, there has been increasing emphasis on a sustainable dietary approach to the prevention of subclinical vitamin A deficiency. One part of this can be the production and use of red palm oil as a salad and cooking oil or blended into other vegetable cooking oils. the latter will also improve the caloric density of the diets, a serious limiting factor for young children in the region. It will also add antioxidant activity to the diet.

Prevalence of diarrhea among children less than 36 months of age in rural western China in 2001 and 2005

We collected for rural western China data for 14,658 children less than 36 months of age in 2001 and for 14,112 children in 2005. A generalized estimated equation log-binomial model was used to identify the determinants of childhood diarrhea. In 2005, prevalence of diarrhea was approximately 7.4%, which compared with that for 2001, had decreased by 8.7%. The generalized estimated equation analysis showed that region affected the prevalence of childhood diarrhea significantly. Age was negatively associated with childhood diarrhea. Although childhood upper respiratory infections increased the risk of diarrhea, the risk could be decreased by use of vitamin A in the previous year. In addition, children of Han ethnicity or those living in one-child families had a lower risk of diarrhea in 2001, but underweight children had a higher risk in 2005. These findings may have some implications for formulating policies of childhood diarrhea prevention and control in rural western China.

Effects of dietary vitamin A content on antibody responses of feedlot calves inoculated intramuscularly with an inactivated bovine coronavirus vaccine

OBJECTIVE

To investigate effects of low dietary vitamin A content on antibody responses in feedlot calves inoculated with an inactivated bovine coronavirus (BCoV) vaccine.

ANIMALS

40 feedlot calves.

PROCEDURES

Calves were fed diets containing high (3,300 U/kg) or low (1,100 U/kg) amounts of vitamin A beginning on the day of arrival at a feedlot (day 0) and continuing daily until the end of the study (day 140). Serum retinol concentrations were evaluated in blood samples obtained throughout the study. Calves were inoculated IM with an inactivated BCoV vaccine on days 112 and 126. Blood samples obtained on days 112 and 140 were used for assessment of BCoV-specific serum IgG1, IgG2, IgM, and IgA titers via an ELISA.

RESULTS

The low vitamin A diet reduced serum retinol concentrations between days 112 and 140. After the BCoV inoculation and booster injections, predominantly serum IgG1 antibodies were induced in calves fed the high vitamin A diet; however, IgG1 titers were compromised at day 140 in calves fed the low vitamin A diet. Other isotype antibodies specific for BCoV were not affected by the low vitamin A diet.

CONCLUSIONS AND CLINICAL RELEVANCE

Dietary vitamin A restriction increases marbling in feedlot cattle; however, its effect on antibody responses to vaccines is unknown. A low vitamin A diet compromised the serum IgG1 responses against inactivated BCoV vaccine, which suggested suppressed T-helper 2-associated antibody (IgG1) responses. Thus, low vitamin A diets may compromise the effectiveness of viral vaccines and render calves more susceptible to infectious disease.

Efficacy of a high-dose in addition to daily low-dose vitamin A in children suffering from severe acute malnutrition with other illnesses

Background

Efficacy of high-dose vitamin A (VA) in children suffering from severe acute malnutrition (SAM) has recently been questioned. This study compared the efficacy of a single high-dose (200,000 IU) in addition to daily low-dose (5000 IU) VA in the management of children suffering from SAM with diarrhea and/or acute lower respiratory tract infection (ALRI).

Methods

In a randomized, double-blind, controlled clinical trial in icddr,b, Bangladesh during 2005–07, children aged 6–59 months with weight-for-height <−3 Z-score and/or bipedal edema (SAM) received either a high-dose VA or placebo on admission day. Both the groups received 5,000 IU/day VA in a multivitamins drop for 15 days and other standard treatment which is similar to WHO guidelines.

Results

A total 260 children (130 in each group) were enrolled. All had diarrhea, 54% had concomitant ALRI, 50% had edema, 48.5% were girl with a mean±SD age of 16±10 months. None had clinical signs of VA deficiency. Mean±SD baseline serum retinol was 13.15±9.28 µg/dl, retinol binding protein was 1.27±0.95 mg/dl, and pre-albumin was 7.97±3.96 mg/dl. Median (inter quartile range) of C-reactive protein was 7.8 (2.1, 22.2) mg/L. Children of the two groups did not differ in any baseline characteristic. Over the 15 days treatment period resolution of diarrhea, ALRI, edema, anthropometric changes, and biochemical indicators of VA were similar between the groups. The high-dose VA supplementation in children with SAM did not show any adverse event.

Conclusions

Efficacy of daily low-dose VA compared to an additional single high-dose was not observed to be better in the management of children suffering from SAM with other acute illnesses. A single high-dose VA may be given especially where the children with SAM may leave the hospital/treatment center early.

Trial Registration

ClinicalTrials.gov NCT00388921

Newborn vitamin A supplementation does not affect nasopharyngeal carriage of Streptococcus pneumoniae in Bangladeshi infants at age 3 months

Nasopharyngeal (NP) carriage of S. pneumoniae (Spn) is a risk factor for pneumococcal disease and its transmission. We assessed the impact of vitamin A (VA) supplementation shortly after birth in reducing Spn colonization in early infancy in rural Bangladesh. We recruited 500 infants participating in a cluster-randomized trial that reported a 15% reduction in mortality following receipt of an oral dose of VA (52.25 μmol) compared to placebo. NP specimens were collected at the age of 3 mo to study the effect of VA on the prevalence of culture-confirmed Spn. Analyses were conducted by intention to treat. Spn carriage prevalence did not differ between VA and placebo recipients [OR = 0.83 (95% CI: 0.55-1.27); P = 0.390]. Spn carriage at the age of 3 mo was not lowered by VA given at birth. Results are similar to those from an Indian study in which impact on Spn carriage was assessed at the age of 4 mo [OR = 0.73 (95% CI: 0.48-1.10); P = 0.128]. The point estimate of the pooled effect size for the 2 studies is OR = 0.78 [(95% CI: 0.58-1.04); P = 0.095], which may imply a modest impact on carriage. If so, then the evidence thus far would suggest that Spn carriage reduction is unlikely to be a primary ancillary benefit of newborn VA supplementation.

Recurrent floods and prevalence of diarrhea among under five children: observations from Bahraich district, Uttar Pradesh, India

Background

Diarrhea is an important problem among the under-five children in India.

Objective

The paper examines long-term impacts of recurrent floods on diarrhea among under-five children in Uttar Pradesh, India.

Design

A two stage stratified cluster survey was conducted in flood affected (exposed) and non-flood affected areas (unexposed).

Results

The long-term impact of the floods was not clearly marked in the overall prevalence of diarrhea with the exposed group having prevalence of 55.1% as against 56.2% in the unexposed group of children under five. Economic condition of the household is associated with the prevalence of diarrhea in both exposed and unexposed strata. Anemia was found to be a significant risk factor for diarrhea among children in both the flood exposed and non-flood exposed populations. The recurrent floods did not have any significant effect on the prevalence of diarrhea in relation to gender, religion, caste, and household size.

Conclusions

The study indicates that the long-term impacts of floods are very differently manifested than the immediate impacts.

Duration of hospitalization and appetite of HIV-infected South African children

Human immunodeficiency virus (HIV)-infected children generally show poor growth. Episodes of diarrhoea and pneumonia in HIV-infected children are thought to be more severe than in HIV-uninfected children. The objective of this study was to compare duration of hospitalization, appetite and nutritional status of HIV-infected children with that of uninfected children. A cross-sectional study was performed on children (2-24 months) admitted with diarrhoea or pneumonia to the university hospital. Children were tested for HIV, and the duration of hospitalization was noted for 189 children. Follow-up for blood analysis (n=154) and appetite measurement (n=48) was performed 4-8 weeks after discharge. Appetite was measured as ad libitum intake of a commercial infant cereal using highly standardized procedures. Hospitalization (in days) was significantly longer in HIV-infected children; among children admitted with diarrhoea (5.9 ± 1.9 vs. 3.8 ± 1.5) (mean ± standard deviation) and with pneumonia (9.0 ± 2.5 vs. 5.9 ± 1.9). Serum zinc, iron and transferrin concentrations, and haemoglobin levels were significantly lower in HIV-infected children compared with uninfected children. Appetites [amounts eaten (g) per kg body weight] of HIV-infected children were significantly poorer than those of HIV-uninfected children (18.6 ± 5.8 vs. 25.2 ± 7.4). The eating rates (g min(-1) ) of HIV-infected children were also slower (17.6 ± 6.2 vs. 10.1 ± 3.7) Mean Z-scores for length-for-age were significantly lower among HIV-infected children compared with HIV-uninfected children. Weight-for-length Z-scores were not significantly different. In summary, HIV-infected children had a 55% longer duration of hospitalization and a 21% lower appetite.

The roles of phytochemicals in bronchial asthma

Despite gaps in our knowledge of how phytochemicals interfere with cellular functions, several natural plant products are utilized to prevent or treat a wide range of diseases. Identification of an agent with therapeutic potential requires multiple steps involving in vitro studies, efficacy and toxicity studies in animal models, and then human clinical trials. This review provides a brief introduction on natural products that may help to treat and/or prevent bronchial asthma and describes our current understanding of their molecular mechanisms based on various in vitro, in vivo, and clinical studies. We focus on the anti-inflammatory and anti-vascular actions of the plant products and other roles beyond the anti-oxidative effects.

Micronutrients and HIV infection

The immune system requires several essential micronutrients to maintain an effective immune response. HIV infection destroys the immune system and promotes nutritional deficiencies, which further impair immunity. This article reviews the role of several micronutrients (vitamins A, C, E and D, the B vitamins, and minerals, selenium, iron and zinc) that are relevant for maintaining immune function. In addition, the deficiencies of these micronutrients have been associated with faster progression of HIV-1 disease. This review examines the evidence from observational studies of an association between micronutrient status and HIV disease, as well as the effectiveness of micronutrient supplementation on HIV-disease progression, pregnancy outcomes and nutritional status, among others, utilizing randomized clinical trials. Each micronutrient is introduced with a summary of its functions in human physiology, followed by the presentation of studies conducted in HIV-infected patients in relation to this specific micronutrient. Overall findings and recommendations are then summarized.

Status of vitamins A and E in schoolchildren in the centre west of Tunisia: a population-based study

OBJECTIVE

The present study was undertaken to assess the status of vitamins A and E (VA and VE, respectively) and their main determinants in Tunisian children.

DESIGN

Cross-sectional population-based study.

SETTING

Kasserine Governorate in the centre west of Tunisia.

SUBJECTS

A total of 7407 children attending the first grade of elementary school were included. VA and VE were assessed by HPLC.

RESULTS

The prevalence of moderate VA deficiency (VAD; <0·70 μmol/l) was 2·3 % and VE deficiency (VED; <6·97 μmol/l) was 5·4 %. Low status in VA (0·70-1·05 μmol/l) and VE (6·97-11·61 μmol/l) was observed in 17 % and 20·2 % of children, respectively. No child exhibited severe VA or VE deficiency (<0·35 and <2·32 μmol/l, respectively). The main predictors of VAD were advanced age (OR = 1·65; 95 % CI 1·13, 2·41; P = 0·05) and sickness within the past 2 weeks (OR = 1·51; 95 % CI 1·09, 2·09; P = 0·01). Predictors of VED were living in the peri-urban region (OR = 1·60; 95 % CI 1·28, 2·01; P < 0·001) and sickness within the past 2 weeks (OR = 0·75; 95 % CI 0·60, 0·94; P = 0·01).

CONCLUSIONS

Moderate VAD and VED were uncommon in Tunisian children. However, low status in VA and/or VE remains frequent. A reinforcement of the national strategies for children's nutrition and health is needed, particularly in disadvantaged regions. Supplementation of VA and VE is not necessary in Tunisia, but food fortification may be beneficial.

Is there an association between the nutritional status of the mother and that of her 2-year-old to 5-year-old child?

The aim of this study was to determine whether there is an association between the nutritional status of the mother and that of her 2-year-old to 5-year-old child in a rural village in South Africa where there is a high prevalence of childhood malnutrition (in particular, deficiencies of vitamin A and iron) and of maternal obesity. A blood sample and anthropometric measurements were obtained for 118 child-mother pairs. There was a positive mother-child correlation for serum ferritin (R=0.2304, P<0.05) and haemoglobin (R=0.2664, P<0.01) concentrations, respectively. The child of an anaemic mother had a relative risk of 1.632 of also being anaemic. There was no mother-child association for either serum retinol concentration or anthropometric measurements. Serum retinol concentrations showed a positive correlation with both serum ferritin (mothers only; R=0.2161, P<0.01) and haemoglobin (R=0.2807, P<0.01 for mothers; and R=0.2710, P < 0.01 for children) concentrations. The mother-child association for iron status is probably because of an inadequate dietary intake and low bioavailability of dietary iron, which are major causes of iron deficiency. The lack of mother-child association for serum retinol concentration could probably be ascribed to the fact that children are more susceptible to vitamin A deficiency than adults because of childhood diseases.

Neonatal vitamin A deficiency and its impact on acute respiratory infections among preschool Inuit children

OBJECTIVE

To assess if vitamin A concentration in umbilical cord blood is associated with incidence and severity of respiratory infections in preschool Inuit children from Nunavik (Québec, Canada).

METHOD

The medical charts of 305 children were reviewed from 0 to 5 years of age. The association between vitamin A concentration in umbilical cord plasma and the incidence rates of acute otitis media (AOM), lower respiratory tract infections (LRTIs) and hospitalization rates for LRTIs was evaluated using Poisson regression.

RESULTS

Compared to children with vitamin A concentration > or =20 microg/dl, adjusted rate ratios (RR) for children below 20 microg/dl ranged between 1.06-1.62 for AOM, 1.12-1.34 for LRTIs, and 1.09-1.43 for hospitalization for LRTIs. Most RRs were statistically significant for AOM and LRTIs, but not for hospitalization for LRTIs.

CONCLUSION

Neonatal vitamin A deficiency appears to be a significant risk factor for AOM and LRTIs in this population.

Pneumonia research to reduce childhood mortality in the developing world

Pneumonia is an illness, usually caused by infection, in which the lungs become inflamed and congested, reducing oxygen exchange and leading to cough and breathlessness. It affects individuals of all ages but occurs most frequently in children and the elderly. Among children, pneumonia is the most common cause of death worldwide. Historically, in developed countries, deaths from pneumonia have been reduced by improvements in living conditions, air quality, and nutrition. In the developing world today, many deaths from pneumonia are also preventable by immunization or access to simple, effective treatments. However, as we highlight here, there are critical gaps in our understanding of the epidemiology, etiology, and pathophysiology of pneumonia that, if filled, could accelerate the control of pneumonia and reduce early childhood mortality.

Undernutrition, infection and immune function

Undernutrition and infection are the major causes of morbidity and mortality in the developing world. These two problems are interrelated. Undernutrition compromises barrier function, allowing easier access by pathogens, and compromises immune function, decreasing the ability of the host to eliminate pathogens once they enter the body. Thus, malnutrition predisposes to infections. Infections can alter nutritional status mediated by changes in dietary intake, absorption and nutrient requirements and losses of endogenous nutrients. Thus, the presence of infections can contribute to the malnourished state. The global burden of malnutrition and infectious disease is immense, especially amongst children. Childhood infections impair growth and development. There is a role for breast-feeding in protection against infections. Key nutrients required for an efficient immune response include vitamin A, Fe, Zn and Cu. There is some evidence that provision of the first three of these nutrients does improve immune function in undernourished children and can reduce the morbidity and mortality of some infectious diseases including measles, diarrhoeal disease and upper and lower respiratory tract infections. Not all studies, however, show benefit of single nutrient supplementation and this might be because the subjects studied have multiple nutrient deficiencies. The situation regarding Fe supplementation is particularly complex. In addition to immunization programmes and improvement of nutrient status, there are important roles for maternal education, improved hygiene and sanitation and increased supply of quality water in the eradication of infectious diseases.

Plasma lycopene and antioxidant vitamins in asthma: the PLAVA study

OBJECTIVE

Scientific evidence suggests that lycopene and antioxidant vitamins have significant antioxidant and protective effects.

METHODS

This case-control study included 96 subjects (40 asthmatics, 56 healthy control subjects). Baseline blood samples, pulmonary function tests, and clinical and alimentary histories were collected. All subjects were grouped by age, sex, cigarette smoking habit, body mass index, alimentary intake, and atopic status.

RESULTS

Serum lycopene concentration was significantly lower in asthmatic subjects than in healthy control subjects (0.10+/-0.7 micromoL/L vs. 0.16+/-0.8 micromoL/L--p<0.001). Serum vitamin A concentration was significantly lower in asthmatics (2.38+/-0.37 micromoL/L) in respect to control subjects (3.06+/-0.56 micromoL/L) (p<0.01). Plasma serum concentration of vitamin E and beta-carotene were not found to be different in the two groups.

CONCLUSIONS

Dietary supplementation or adequate intake of lycopene and vitamin A rich foods may be beneficial in asthmatic subjects.

Decreased Serum Retinol Is Associated with Increased Mortality in Renal Transplant Recipients

Background: Vitamin A plays a central role in epithelial integrity and immune function. Given the risk of infection after transplantation, adequate vitamin A concentrations may be important in patients with a transplant. We assessed whether there was an association between retinol concentration and all-cause mortality in renal transplant recipients.

Methods: We recruited 379 asymptomatic renal transplant recipients between June 2000 and December 2002. We measured serum retinol at baseline and collected prospective follow-up data at a median of 1739 days.

Results: Retinol was significantly decreased in those renal transplant recipients who had died at follow-up compared with those who were still alive at follow-up. Kaplan–Meier analysis showed that retinol concentration was a significant predictor of mortality. In multivariate Cox regression analysis, decreased retinol concentration remained a statistically significant predictor of all-cause mortality after adjustment for traditional cardiovascular risk factors, high-sensitivity C-reactive protein, and estimated glomerular filtration rate.

Conclusions: Serum retinol concentration is a significant independent predictor of all-cause mortality in renal transplantation patients. Higher retinol concentration might impart a survival advantage via an antiinflammatory or anti-infective mechanism.

Adjuvant effect of vitamin A on recurrent lower urinary tract infections

BACKGROUND

The purpose of the present paper was to investigate the effects of vitamin A supplementation on recurrent lower urinary tract infections (RUTI).

METHODS

Twenty-four patients with non-complicated RUTI were included in a placebo-controlled, double-blinded study. Twelve patients received a single dose of 200,000 IU vitamin A in addition to antimicrobial therapy. Patient and control groups (each containing 12 patients) were followed for up to 1 year and were evaluated for eradication and frequency of lower urinary tract infections (UTI). Serum levels of vitamin A and beta-carotene were determined periodically.

RESULTS

During the first 6 months follow-up period the infection rate of the vitamin A-supplemented group reduced from 3.58 to 0.75 per 6 months, and in the subsequent 6 months the infection rate was 1.75 per 6 months. These values were calculated as 2.75, 2.83 and 2.66, respectively, in the placebo group.

CONCLUSION

Vitamin A supplementation may have an adjuvant effect on the treatment of RUTI.

Malnutrition and morbidity are higher in children who are missed by periodic vitamin A capsule distribution for child survival in rural Indonesia

Universal periodic high-dose vitamin A capsule distribution is a cost-effective intervention to increase child survival in developing countries. It is unclear whether children who are missed by the program are at higher risk for malnutrition and infectious disease morbidity. Based on data from the Nutritional Surveillance System, we compared nutritional status and other health indicators of children aged 12-59 mo in rural Indonesia who did and did not receive a vitamin A capsule within the last 6 mo. A total of 241,087 of 335,034 children (72.0%) received a vitamin A capsule between 1999 and 2003. In children who did and did not receive a vitamin A capsule, respectively, the proportion with weight-for-age, height-for-age, and weight-for-height Z scores <-2 were 37.0 vs. 42.5%, 39.2 vs. 45.6%, and 6.9 vs. 7.4% (P < 0.0001). Similarly, the proportion with anemia, diarrhea during the last wk, current diarrhea, and current fever was 49.2 vs. 54.8%, 6.7 vs. 8.4%, 4.4 vs. 6.0%, and 1.4 vs. 1.7% (P < 0.0001). Children who did not receive vitamin A were also less likely to have received childhood immunizations and belonged to families with higher infant and under-5-y child mortality than children who receive vitamin A. Although a lack of access to other public health interventions and demographic factors may also contribute to the rate of malnutrition in children missed by the vitamin A capsule program, it is likely that increased coverage of vitamin A supplementation would help to maximize the benefits for child survival.

The role of selenium, zinc and antioxidant vitamin supplementation in the treatment of bronchial asthma: adjuvant therapy or not?

In the last few years, nutrition has represented an important conditioning factor of many cardiovascular, gastrointestinal and pulmonary chronic diseases. Many published works have documented specific inflammatory abnormalities in the airways of subjects with mild-to-moderate persistent bronchial asthma in which the inflammation state is often associated with an increased generation of reactive oxygen species and free radical-mediated reactions. This evidence has stimulated many researchers to suppose that the oxidative stress could be an important pathogenetic determining factor in the progression of chronic diseases, and the decrease of oxidant insults to the lung can be modified with antioxidant supplementary therapy. There are many studies regarding dietary interventions that confirm the relationship to oxidative stress, bronchial inflammation, the development of asthmatic symptoms and the lowered cellular reducing capacity. Simple dietary and environmental supplementations significantly reduce the oxidant stress, minimise the development of asthmatic symptoms, and should prove to be an effective new approach to asthma management in addition to current pharmacological strategies. Many randomised controlled trials with antioxidant vitamins and trace element supplements have not confirmed the results shown in other clinical trials. The aim of this review is to focus the attention on published works discussing the relationship between asthma and nutritional supplements (some trace elements and vitamins) and the effectiveness of these supplements in the treatment of bronchial asthma.

Human health implications of environmental contaminants in Arctic Canada: A review

The objectives of this paper are to: assess the impact of exposure to current levels of environmental contaminants in the Canadian Arctic on human health; identify the data and knowledge gaps that need to be filled by future human health research and monitoring; examine how these issues have changed since our first assessment [Van Oostdam, J., Gilman, A., Dewailly, E., Usher, P., Wheatley, B., Kuhnlein, H. et al., 1999. Human health implications of environmental contaminants in Arctic Canada: a review. Sci Total Environ 230, 1-82]. The primary exposure pathway for contaminants for various organochlorines (OCs) and toxic metals is through the traditional northern diet. Exposures tend to be higher in the eastern than the western Canadian Arctic. In recent dietary surveys among five Inuit regions, mean intakes by 20- to 40-year-old adults in Baffin, Kivalliq and Inuvialuit communities exceeded the provisional tolerable daily intakes (pTDIs) for the OCs, chlordane and toxaphene. The most recent findings in NWT and Nunavut indicate that almost half of the blood samples from Inuit mothers exceeded the level of concern value of 5 microg/L for PCBs, but none exceeded the action level of 100 microg/L. For Dene/Métis and Caucasians of the Northwest Territories exposure to OCs are mostly below this level of concern. Based on the exceedances of the pTDI and of various blood guidelines, mercury and to a lesser extent lead (from the use of lead shot in hunting game) are also concerns among Arctic peoples. The developing foetus is likely to be more sensitive to the effects of OCs and metals than adults, and is the age groups of greatest risk in the Arctic. Studies of infant development in Nunavik have linked deficits in immune function, an increase in childhood respiratory infections and birth weight to prenatal exposure to OCs. Balancing the risks and benefits of a diet of country foods is very difficult. The nutritional benefits of country food and its contribution to the total diet are substantial. Country food contributes significantly more protein, iron and zinc to the diets of consumers than southern/market foods. The increase in obesity, diabetes and cardiovascular disease has been linked to a shift away from a country food diet and a less active lifestyle. These foods are an integral component of good health among Aboriginal peoples. The social, cultural, spiritual, nutritional and economic benefits of these foods must be considered in concert with the risks of exposure to environmental contaminants through their exposure. Consequently, the contamination of country food raises problems which go far beyond the usual confines of public health and cannot be resolved simply by risk-based health advisories or food substitutions alone. All decisions should involve the community and consider many aspects of socio-cultural stability to arrive at a decision that will be the most protective and least detrimental to the communities.

Nutritional status and diarrheal illness as independent risk factors for alveolar pneumonia

Community-acquired alveolar pneumonia (CAAP) is typically associated with bacterial infections and is especially prevalent in vulnerable populations worldwide. The authors studied nutritional status and diarrheal history as risk factors for CAAP in Bedouin children <5 years of age living in Israel. In this prospective case-control study (2001-2002), 334 children with radiographically confirmed CAAP were compared with 529 controls without pneumonia with regard to nutritional status and diarrhea history. Controls were frequency matched to cases on age and enrollment month. Logistic regression models were used to evaluate associations of CAAP with nutritional status and recent diarrhea experience. Anemia (adjusted odds ratio (AOR) = 3.32, 95% confidence interval (CI): 2.24, 4.94; p < 0.001), low birth weight (AOR = 2.16, 95% CI: 1.32, 3.54; p = 0.002), stunting (AOR = 2.22, 95% CI: 1.31, 3.78; p = 0.004), serum retinol concentration (AOR = 1.03 per microg/dl, 95% CI: 1.02, 1.05; p < 0.001), and having > or =1 diarrhea episodes within 31 days prior to enrollment (AOR = 2.30, 95% CI: 1.26, 4.19; p = 0.007) were identified as risk factors for CAAP. Results suggest that improving antenatal care and the nutritional status of infants may reduce the risk of CAAP in Bedouin children. Furthermore, they suggest that vaccines developed to prevent diarrhea may also lower the risk of CAAP.

Effects of moderate doses of vitamin A as an adjunct to the treatment of pneumonia in underweight and normal-weight children: a randomized, double-blind, placebo-controlled trial

BACKGROUND

Randomized controlled trials have shown inconsistent responses of childhood pneumonia to the use of vitamin A as an adjunct to the standard treatment of pneumonia.

OBJECTIVE

We evaluated the effect of a moderate dose of vitamin A as an adjunct to standard antimicrobial treatment on the duration of respiratory signs in children with pneumonia.

DESIGN

Children, aged 2-59 mo, with pneumonia and weight-for-age <50th percentile who had been admitted to the Baca Ortíz Children's Hospital in Quito, Ecuador, were randomly assigned to receive 50,000 IU (aged 2-12 mo) or 100,000 IU (aged >12-59 mo) vitamin A or a placebo.

RESULTS

Of the 287 children enrolled, 145 received vitamin A and 142 received placebo. No overall differences were observed between the 2 groups in the duration of signs of pneumonia. Multiple linear regression showed a significant interaction between basal serum retinol concentration and vitamin A group for the time (in h) to remission of respiratory signs (beta = -3.57, SE = 1.09, P = 0.001). Duration of clinical signs was less in children with basal serum retinol concentrations >200 microg/L who received vitamin A supplements than in children with similar concentrations who received placebo (69.9 +/- 49.9 h compared with 131.3 +/- 143.9 h; P = 0.049).

CONCLUSIONS

Overall, we found no effect of a moderate dose of vitamin A supplementation on the duration of uncomplicated pneumonia in underweight or normal-weight children aged <5 y. However, a beneficial effect was seen in children with high basal serum retinol concentrations.

Vitamin A for treating measles in children

BACKGROUND

Measles is a major cause of childhood morbidity and mortality. Vitamin A deficiency is a recognized risk factor for severe measles infections. The World Health Organization (WHO) recommends administration of an oral dose of vitamin A (200,000 international units (IU), or 100,000 IU in infants) each day for two days to children with measles when they live in areas where vitamin A deficiency may be present.

OBJECTIVES

To determine whether vitamin A therapy, commenced after measles has been diagnosed, is beneficial in preventing mortality, pneumonia and other secondary complications in children.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 1, 2005), MEDLINE (1966 to March 2005), EMBASE (1980 to December 2004) and looked for unpublished studies.

SELECTION CRITERIA

Only randomized controlled trials in which children with measles were given vitamin A or placebo along with standard treatment were considered.

DATA COLLECTION AND ANALYSIS

Studies were assessed independently by two authors. The analysis of dichotomous outcomes was done using the StatXact software and results expressed as relative risk (RR) with 95% confidence interval (CI). Subgroup analyses were carried out for dose, formulation, age, hospitalization and pneumonia-specific mortality. Weighted mean differences (WMD) with 95% CI were calculated for continuous outcomes.

MAIN RESULTS

There was no significant reduction in the risk of mortality in the vitamin A group when all the studies were pooled using the random-effects model (RR 0.70; 95% CI 0.42 to 1.15). Using two doses of vitamin A (200,000 IU) on consecutive days was associated with a reduction in the risk of mortality in children under the age of two years (RR 0.18; 95% CI 0.03 to 0.61) and a reduction in the risk of pneumonia-specific mortality (RR 0.33; 95% CI 0.08 to 0.92). There was no evidence that vitamin A in a single dose was associated with a reduced risk of mortality among children with measles. There was a reduction in the incidence of croup (RR 0.53; 95% CI 0.29 to 0.89) but no significant reduction in the incidence of pneumonia (RR 0.92; 95% CI 0.69 to 1.22) or diarrhoea (RR 0.80; 95% CI 0.27 to 2.34) with two doses.

AUTHORS' CONCLUSIONS

Although we found no overall significant reduction in mortality with vitamin A therapy for children with measles there was evidence that two doses were associated with a reduced risk of mortality and pneumonia-specific mortality in children under the age of two years. There were no trials that directly compared a single dose with two doses.

Only a small proportion of anemia in northeast Thai schoolchildren is associated with iron deficiency

BACKGROUND

Iron deficiency is assumed to be the major cause of anemia in northeast Thailand, but other factors may be involved.

OBJECTIVE

We determined the prevalence of anemia among schoolchildren in northeast Thailand and the role of hemoglobinopathies, selected micronutrient deficiencies, and other factors in hemoglobin status.

DESIGN

Blood samples were collected from 567 children aged 6-12.9 y attending 10 primary schools for the determination of a complete blood count and hemoglobin type [Hb AA (normal hemoglobin), Hb AE (heterozygous for Hb type E), and Hb EE (homozygous for Hb type E)] and the measurement of serum ferritin, transferrin receptor, retinol, vitamin B-12, and plasma and erythrocyte folate concentrations. Children with a C-reactive protein concentration > or = 10 mg/L (n = 12), which indicated infection, were excluded.

RESULTS

The prevalence of anemia was 31%. Age, hemoglobin type, and serum retinol were the major predictors of hemoglobin concentration. Hb AA and Hb AE children with anemia had lower (P < 0.01) hematocrit, mean cell volume, and serum retinol values than did their nonanemic counterparts; no significant differences in serum ferritin were found by hemoglobin type. Only 16% (n = 22) of the anemic Hb AA and Hb AE children were iron deficient. Hb AA and Hb AE children with a serum retinol concentration <0.70 micromol/L (n = 14) had a significantly higher geometric mean serum ferritin concentration than did those with a retinol concentration > or = 0.70 micromol/L (P = 0.009); no significant difference in transferrin receptor concentrations was found between these 2 groups.

CONCLUSIONS

Hemoglobinopathies, suboptimal vitamin A status, and age were the major predictors of hemoglobin concentration. The contribution of iron deficiency to anemia was low, and its detection was complicated by coexisting suboptimal vitamin A status.

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.

Vitamin A deficiency and xerophthalmia among school-aged children in Southeastern Asia

OBJECTIVE

To determine provisional estimates of the extent of vitamin A (VA) deficiency and xerophthalmia among school-aged children.

DESIGN

Literature search of published, unpublished and website-based population survey and study reports, with country-specific imputation of prevalence rates and numbers of children affected by: (1) VA deficiency based on measured or imputed distributions of serum retinol concentration < 0.70 micromol/l (equivalent to < 20 microg/dl) and (2) xerophthalmia, by country.

SETTING

Countries within the WHO South-East Asian Region.

SUBJECTS

The target group for estimation was children 5-15 y of age.

INTERVENTIONS

None.

RESULTS

The estimated prevalence of VA deficiency is 23.4%, suggesting that there are approximately 83 million VA-deficient school-aged children in the region, of whom 10.9% (9 million, at an overall prevalence of 2.6%) have mild xerophthalmia (night blindness or Bitot's spot). Potentially blinding corneal xerophthalmia appears to be negligible at this age.

CONCLUSIONS

VA deficiency, including mild xerophthalmia, appears to affect large numbers of school-aged children in South-East Asia. However, nationally representative data on the prevalence, risk factors and health consequences of VA deficiency among school-aged children are lacking within the region and globally, representing a future public health research priority.

Retinoids and drugs of abuse: implications for neurological disease risk in human immunodeficiency virus type 1 infection

Among injection drug users, human immunodeficiency virus (HIV) type 1 infection may be associated with an increased risk of nervous system disease. For HIV-infected drug users with vitamin A deficiency, the overall risk of HIV-related morbidity and mortality may also be higher. In previous studies, levels of retinol, retinol-binding protein, and transthyretin in samples from such individuals were examined and found to be lower than such levels in seronegative control subjects. Also, in studies using an activated mononuclear cell line, all-trans retinoic acid and 9-cis retinoic acid suppressed production of the tumor necrosis factor (TNF)-alpha and interferon (IFN)-gamma. However, simultaneous exposure of the cells to morphine at a concentration similar to that to which drug users are exposed resulted in increased production of these cytokines. Therefore, morphine may alter the immunomodulatory effects of retinoids, thereby potentially affecting the clinical outcome of studies involving retinoid administration to HIV-infected drug users and increasing the risk for the development of HIV-related complications, including neurological disease.

Vitamin A and infancy. Biochemical, functional, and clinical aspects

Vitamin A is a very intriguing natural compound. The molecule not only has a complex array of physiological functions, but also represents the precursor of promising and powerful new pharmacological agents. Although several aspects of human retinol metabolism, including absorption and tissue delivery, have been clarified, the type and amounts of vitamin A derivatives that are intracellularly produced remain quite elusive. In addition, their precise function and targets still need to be identified. Retinoic acids, undoubtedly, play a major role in explaining activities of retinol, but, recently, a large number of physiological functions have been attributed to different retinoids and to vitamin A itself. One of the primary roles this vitamin plays is in embryogenesis. Almost all steps in organogenesis are controlled by retinoic acids, thus suggesting that retinol is necessary for proper development of embryonic tissues. These considerations point to the dramatic importance of a sufficient intake of vitamin A and explain the consequences if intake of retinol is deficient. However, hypervitaminosis A also has a number of remarkable negative consequences, which, in same cases, could be fatal. Thus, the use of large doses of retinol in the treatment of some human diseases and the use of megavitamin therapy for certain chronic disorders as well as the growing tendency toward vitamin faddism should alert physicians to the possibility of vitamin overdose.

Diagnostic accuracy of stool assays for inflammatory bacterial gastroenteritis in developed and resource-poor countries

Because acute bacterial gastroenteritis is often inflammatory, rapid stool assays that detect intestinal inflammation might be used to distinguish between bacterial and nonbacterial gastroenteritis. We performed meta-analyses to determine the discriminatory power, in developed and in resource-poor countries, of rapid stool assays that test for lactoferrin, fecal leukocytes, fecal erythrocytes, and occult blood. In developed countries, the area under the summary receiver operating characteristic curve (AUC/SROC) was 0.89 for fecal leukocytes and 0.81 for occult blood. In resource-poor countries, the AUC/SROC was 0.79 for lactoferrin, 0.72 for fecal leukocytes, 0.63 for occult blood, and 0.61 for fecal erythrocytes. In developed countries, positive and negative likelihood ratios (LR+ and LR-, respectively) for fecal leukocytes were 4.56 and 0.32 when a threshold of >5 cells/high-power field was used, compared with 2.94 and 0.6 in resource-poor countries; for lactoferrin, LR+ was 1.34 and LR- was 0.17 in resource-poor countries when the threshold was an agglutination rating of "+" and a dilution of 1:50. In developing countries, rapid stool assays performed poorly, whereas in developed countries, tests for fecal leukocytes, lactoferrin, and occult blood were moderately useful and could identify patients who were more likely to benefit from empirical antibiotic therapy.

Uptake of vitamin A in buccal mucosal cells after topical application of retinyl palmitate: a randomised, placebo-controlled and double-blind trial

Retinoids have been reported to produce regressions in metaplastic changes of the mucosal epithelium. In order to define the role of these micronutrients in the prevention of squamous metaplasia of the oral cavity, it is necessary to measure their uptake in target tissues such as the buccal mucosal epithelium. We demonstrated in a trial that retinyl palmitate applied topically via a toothpaste is taken up by buccal mucosal cells in young healthy volunteers. In the randomised, parallel-designed, placebo-controlled and double-blind trial, forty volunteers divided in two groups cleaned their teeth either with a placebo toothpaste or a retinyl palmitate-containing toothpaste (1 mg/g) for 56 d. Buccal mucosal cells samples were taken from the healthy volunteers during the retinyl palmitate application and the following wash-out phase to determine the concentration of retinyl palmitate and retinol by HPLC. Supplementary blood samples were taken from the volunteers on days 0 and 56 to investigate changes in plasma retinyl palmitate and retinol concentrations. Results from only thirty participants (sixteen placebo and fourteen treated subjects) were used in the statistical evaluation as the remaining sample results were spoiled by a technical defect during the HPLC analysis. A significant (P<0.05) uptake of retinyl palmitate in buccal mucosal cells after 7 d and a significant (P<0.05) increase of plasma retinol after 17 d was demonstrated in our present study. The uptake of retinyl palmitate and the following hydrolysis to retinol led to an enrichment of vitamin A in buccal mucosal cells.

Vitamin A supplementation and childhood morbidity from diarrhea and respiratory infections: a meta-analysis

OBJECTIVES

To perform an updated meta-analysis of the effect of vitamin A supplementation on childhood morbidity from respiratory tract infections and diarrhea. Study design A comprehensive search of the 1966 to 2000 MEDLINE database and review of the reference lists of relevant articles identified 9 randomized controlled trials dealing with morbidity from respiratory infections and diarrhea in children 6 months to 7 years of age and provided "intention-to-treat" data.

RESULTS

The combined results indicated that vitamin A supplementation has no consistent overall protective effect on the incidence of diarrhea (relative risk, 1.00; 95% CI, 0.94-1.07) and that it slightly increases the incidence of respiratory tract infections (relative risk, 1.08; 95% CI, 1.05-1.11).

CONCLUSIONS

High-dose vitamin A supplements are not recommended on a routine basis for all preschool children and should be offered only to individuals or populations with vitamin A deficiency.

A household survey on morbidity and treatment of acute respiratory infections in communities in Vietnam

OBJECTIVE

To ascertain the extent of under-utilization and insufficiency or inappropriateness in provision of health services as one of the possible causes of high mortality from pediatric pneumonia in pilot areas in Vietnam.

METHOD

The household survey on morbidity and treatment of acute respiratory infections, simple cough, and cold and pneumonia, was conducted in two communities with 10% sampling of the child population.

RESULTS

Both under-treatment of "fast breathing", a proxy for pneumonia, and over-treatment of simple cough and cold with antimicrobials by health workers, mothers, and private practitioners were common.

CONCLUSIONS

A household survey on morbidity and treatment was found to be useful to clarify actual practices in the treatment of acute respiratory infections in the community, which cannot be obtained by mere interview with health workers or mothers. Since a change of knowledge did not automatically lead to change of practice, the training of health workers, health education of mothers and provision of antimicrobials at village health stations would not guarantee improved practice of health workers and mothers. Therefore, constant supervision for health workers, continued health education of mothers and involvement of private practitioners are needed to improve the situation.

Effects of vitamin A deficiency during pregnancy on maternal and child health

OBJECTIVE

To examine the association between biochemical vitamin A deficiency in pregnancy and maternal and fetal health.

DESIGN

A cross sectional clinical study.

SETTING

Antenatal clinic of nutrition unit of Niloufer Hospital catering for a low socio-economic population, and a private nursing home (Swapna nursing home) catering for a high socio-economic population.

POPULATION

736 pregnant women in their third trimester of pregnancy belonging to low (n = 522) and high socio-economic groups (n = 214).

METHODS

All the women were subjected to a detailed clinical, anthropometric and obstetric examination. Night blindness was assessed by administering the standard WHO questionnaire. Birthweight and gestational age of the infants, maternal anaemia and development of pregnancy-induced hypertension in the mother were recorded. Haemoglobin and serum retinol were estimated at the time of recruitment to the study.

MAIN OUTCOME MEASURES

Serum retinol levels, anaemia, pregnancy-induced hypertension, birthweight and gestational age of the infant.

RESULTS

Night blindness was observed in 2.9% of the women and subclincal vitamin A deficiency (serum retinol <20 microg/dL with no clinical signs) in 27% of the women. Moderate to severe anaemia was observed in 41.2% of the women, and 15.8% of the women developed pregnancy-induced hypertension. Sixty-one (9.4%) women delivered preterm. Univariate analysis identified a significant association between serum retinol <20 microg/dL and preterm delivery (OR = 1.74, 95% CI 1.03-2.96), maternal anaemia (OR = 1.82, 95% CI 1.28-2.60) and pregnancy-induced hypertension (OR = 1.56, 95% CI 1.02-2.83). After adjusting for the confounding variables (body mass index, parity, age and socio-economic status) in a multivariate analysis, the significant associations between serum retinol <20 microg/dL and preterm delivery (P = 0.02) and anaemia (P = 0.003) persisted, while that for pregnancy-induced hypertension disappeared (P = 0.71).

CONCLUSION

The study suggests that subclinical vitamin A deficiency is a problem during the third trimester of pregnancy. Serum concentration of retinol <20 microg/dL appears to indicate a deficient status, and is associated with an increased risk of preterm delivery and maternal anaemia.

Vitamin A status in children with asthma

Low vitamin A levels have been found in a number of diseases in children. The aim of this study was to examine the vitamin A status in children with asthma and to correlate the changes with severity of disease. Serum levels of vitamin A, retinol-binding protein (RBP), and albumin were estimated in 35 asthmatic children (24 males) in the age group of 2-12 years (mean 5.89 years) and 29 controls (19 males). Both study and control groups were similar with respect to age, sex, and overall nutritional status. Twenty-four children in the study group (68.6%) had moderate to severe persistent asthma and eight children had mild persistent asthma. Only three patients suffered from mild intermittent asthma. Vitamin A levels in children with asthma (mean +/- SD 22.14 +/- 5.38 microg/dl) were found to be significantly lower than their controls (mean +/- SD 27.54 +/- 4.83 microg/dl) (p = 0.0001). Age, age of onset of asthma, and gender had no correlation with serum vitamin A levels. Low serum vitamin A levels (< 20 microg/dl) were observed four times more commonly in the study group (28.6%) than controls (6.9%). Severity of asthma had a negative correlation with serum vitamin A levels (r = - 0.61, p = 0.0001). Children with severe persistent asthma had markedly low serum vitamin A levels (mean +/- SD 13.42 +/- 5.19 microg/dl) as compared with mild intermittent asthma (mean +/- SD 24.61 +/- 2.32 microg/dl). Therapeutic trials are needed to prove whether low vitamin A levels contribute to asthma severity and the clinical utility of vitamin A supplementation in asthmatic children.

Vitamin A levels and immunity in humans

In animal studies, vitamin A deficiency induces a shift from type 2 (humoral) to type 1 (cellular) cytokines; there are no similar data for humans. Control of human immunodeficiency virus (HIV) and Mycobacterium tuberculosis infections requires type 1 cytokine (cellular) immunity. These infections and vitamin A deficiency are highly prevalent in Africa. We therefore examined the interactions among serum vitamin A levels, immune parameters, HIV infection status, Mycobacterium bovis BCG vaccine scarring (as an indicator of a type 1 cytokine profile), and clinical findings for 70 hospitalized children in Malawi, Africa. Directly conjugated monoclonal antibodies and flow cytometry were used to assess cell-specific cytokine production by peripheral blood monocytes and lymphocyte subpopulations. The statistical techniques employed included nonparametric statistics and logistic regression analyses. Thirty percent of the participants had severe vitamin A deficiency (<10 microg/dl), 34% had moderate deficiency (10 to <20 microg/dl), and 36% had normal levels (> or = 20 microg/dl). Vitamin A levels were lower for HIV-positive than for HIV-negative children (median, 10 and 17 microg/dl, respectively). Vitamin A-deficient children (<20 microg/dl) were more likely than non-vitamin A-deficient children to have higher proportions of natural killer (NK) cells (median, 8.3 and 5.2%, respectively) and lower ratios of interleukin-10-producing monocytes to tumor necrosis factor alpha-producing monocytes after induction (median, 1.0 and 2.3, respectively). Vitamin A-deficient children were also more likely than non-vitamin A-deficient children to exhibit respiratory symptoms (47% versus 12%) and visible BCG vaccine scars (83% versus 48%), which are indicative of a type 1 response to vaccination. Vitamin A status did not vary with gender, age, incidence of malaria parasitemia, blood culture positivity, or rates of mortality (6% of vitamin A-deficient children died versus 20% of non-vitamin A-deficient children). Lower vitamin A levels were associated with a relative type 1 cytokine dominance and proportionately more NK cells, both of which may be somewhat beneficial to persons who are exposed to HIV, M. tuberculosis, or other type 1 pathogens.