Impact of massive dose of vitamin A given to preschool children with acute diarrhoea on subsequent respiratory and diarrhoeal morbidity

Carotenoids: Role in Neurodegenerative Diseases Remediation

Numerous factors can contribute to the development of neurodegenerative disorders (NDs), such as Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, Huntington's disease, and multiple sclerosis. Oxidative stress (OS), a fairly common ND symptom, can be caused by more reactive oxygen species being made. In addition, the pathological state of NDs, which includes a high number of protein aggregates, could make chronic inflammation worse by activating microglia. Carotenoids, often known as "CTs", are pigments that exist naturally and play a vital role in the prevention of several brain illnesses. CTs are organic pigments with major significance in ND prevention. More than 600 CTs have been discovered in nature, and they may be found in a wide variety of creatures. Different forms of CTs are responsible for the red, yellow, and orange pigments seen in many animals and plants. Because of their unique structure, CTs exhibit a wide range of bioactive effects, such as anti-inflammatory and antioxidant effects. The preventive effects of CTs have led researchers to find a strong correlation between CT levels in the body and the avoidance and treatment of several ailments, including NDs. To further understand the connection between OS, neuroinflammation, and NDs, a literature review has been compiled. In addition, we have focused on the anti-inflammatory and antioxidant properties of CTs for the treatment and management of NDs.

Role of Vitamin A Supplementation in Prevention and Control of Coronavirus Disease-19: A Narrative Review

Coronavirus disease-19 (COVID-19) caused by SARS-CoV-2 is a novel viral infectious disease, which broke out in the end of winter season 2019 in China and soon became a pandemic. Characteristically there was severe local and systemic immune-inflammatory response to the virus, damaging the respiratory system and other organ systems. The morbidity and mortality caused by the disease are producing tremendous impact on health. The understanding about pathogenesis and manifestations of the disease was obscure. To date, no classic treatment or preventive measure was available for COVID-19 other than symptomatic and supportive care or few drugs under trial. A possibility exists that maintaining vitamin A adequate levels can protect the affected respiratory mucosa, increase antimicrobial activity, produce better antibody response, and have antiinflammatory effects, thereby promoting repair and healing as well. It has been discussed in the review that by various mechanisms, immune regulation through vitamin A supplementation is beneficial to boost immunity in the current outbreak situation when the population is susceptible to the disease. There is a high possibility that vitamin A supplementation to cases as well as population at risk of COVID-19 has a key role in prevention and control. Hence, it is believed that along with other therapeutic and preventive measures, maintaining vitamin A sufficiency during and prior to the development of active disease may act as an adjuvant in population at risk and cases to prevent and control COVID-19.

Nutrient supplementation for prevention of viral respiratory tract infections in healthy subjects: A systematic review and meta-analysis

It remains uncertain as to whether nutrient supplementation for the general population considered healthy could be useful in the prevention of RTIs, such as COVID-19. In this systematic review and meta-analysis, the evidence was evaluated for primary prevention of any viral respiratory tract infection (RTI) such as SARS-CoV-2, through supplementation of nutrients with a recognized role in immune function: multiple micronutrients, vitamin A, folic acid, vitamin B12, C, D, E, beta-carotene, zinc, iron and long-chain polyunsaturated fatty acids. The search produced 15,163 records of which 93 papers (based on 115 studies) met the inclusion criteria, resulting in 199,055 subjects (191,636 children and 7,419 adults) from 37 countries. Sixty-three studies were included in the meta-analyses, which was performed for children and adults separately. By stratifying the meta-analysis by world regions, only studies performed in Asia showed a significant but heterogeneous protective effect of zinc supplementation on RTIs (RR 0.86, 95% CI 0.7-0.96, I²  = 79.1%, p = .000). Vitamin D supplementation in adults significantly decreased the incidence of RTI (RR 0.89, 95% CI 0.79-0.99, p = .272), particularly in North America (RR 0.82 95% CI 0.68-0.97), but not in Europe or Oceania. Supplementation of nutrients in the general population has either no or at most a very limited effect on prevention of RTIs. Zinc supplementation appears protective for children in Asia, whilst vitamin D may protect adults in the USA and Canada. In 10/115 (8.7%) studies post-hoc analyses based on stratification for nutritional status was performed. In only one study zinc supplementation was found to be more effective in children with low zinc serum as compared to children with normal zinc serum levels.

Excessive Vitamin A Supplementation Increased the Incidence of Acute Respiratory Tract Infections: A Systematic Review and Meta-Analysis

(1) Background: vitamin A deficiency (VAD) is highly prevalent in children living in poor conditions. It has been suggested that vitamin A supplementation (VAS) may reduce the risk of acute respiratory tract infections (ARTI). Our study provides updates on the effects of oral VAS (alone) in children on ARTI and further explores the effect on interesting subgroups. (2) Methods: eight databases were systematically searched from their inception until 5 July 2021. The assessments of inclusion criteria, extraction of data, and data synthesis were carried out independently by two reviewers. (3) Results: a total of 26 randomized trials involving 50,944 participants fulfilled the inclusion criteria. There was no significant association of VAS with the incidence of ARTI compared with the placebo (RR 1.03, 95% CI 0.92 to 1.15). Subgroup analyses showed that VAS higher than WHO recommendations increased the incidence of ARTI by 13% (RR 1.13, 95% CI 1.07 to 1.20), and in the high-dose intervention group, the incidence rate among well-nourished children rose by 66% (RR 1.66, 95% CI 1.30 to 2.11). (4) Conclusions: no more beneficial effects were seen with VAS in children in the prevention or recovery of acute respiratory infections. Excessive VAS may increase the incidence of ARTI in children with normal nutritional status.

Nutritional Management of Diarrhoea

Diarrhoeal disease may cause, precipitate, or exacerbate protein-energy and micronutrient malnutrition through five possible mechanisms: 1) reduced food intake-reduction of food intake during diarrhoea may be due to the child's anorexia, maternal food-withholding behaviour, or both; 2) decreased absorption of nutrients-structural damage to the intestine, as well as the physical action of increased intestinal movement and reduced fluid transit time, interact to produce decreased absorption of nutrients; 3) increased catabolic losses-under the influence of the inflammatory process, diarrhoea of infectious origin induces an average daily negative nitrogen balance of 0.9 g/kg/day, as muscle protein is converted to glucose through gluconeogenesis by the liver; this glucose is used as a fuel by tissues to sustain the hypermetabolism associated with fever; 4) nutrient loss from the intestine-in diarrhoea nutrients are lost directly from the intestinal tract; 5) metabolic inefficiency due to micronutrient deficiency-the increased rate of tissue synthesis displayed by children recovering from protein-energy malnutrition may be hampered by a limited supply of nutrients from the body pool, which in turn may not be replenished fast enough by dietary intake. The two main driving forces that determine nutritional care of the sick child in the home are advice from healthcare providers (mainly physicians) and the mothers’ own beliefs; a third determinant of care is the social support network available to mothers or social pressure to act in a determined way. Therefore, health providers should be knowledgeable about appropriate feeding management of illness, and should provide sound advice to mothers.

The likelihood that mothers will follow the recommendations given by the health-care system (whether formal or informal) will be greater if these conform to mothers’ cultural norms and their explanatory model of disease. Feeding practices followed in health facilities should be consistent with those advised for the mothers at home. In order to make a successful change in a given practice, culture-sensitive interventions should be used.

Role of Vitamin A in the Immune System

Vitamin A (VitA) is a micronutrient that is crucial for maintaining vision, promoting growth and development, and protecting epithelium and mucus integrity in the body. VitA is known as an anti-inflammation vitamin because of its critical role in enhancing immune function. VitA is involved in the development of the immune system and plays regulatory roles in cellular immune responses and humoral immune processes. VitA has demonstrated a therapeutic effect in the treatment of various infectious diseases. To better understand the relationship between nutrition and the immune system, the authors review recent literature about VitA in immunity research and briefly introduce the clinical application of VitA in the treatment of several infectious diseases.

Time to revisit the strategy of massive vitamin A prophylaxis dose administration to the under five children in India - An analysis of available evidence

Childhood blindness due to corneal ulceration has historically been prevalent among poor Indian children. To tackle this situation the National Institute of Nutrition (NIN), Hyderabad, India, launched (after field-testing) massive dose based national vitamin A (Vit-A) prophylaxis program. Over a period of time reduction in childhood mortality was also hailed as a beneficial effect of the program. Data from the Indian Council for Medical Research (ICMR) indicate that in most Indian states there has been a gradual reduction in the prevalence of Bitot's spots. However, it was not attributed to the prophylaxis program because of its low and patchy coverage. It was, rather, attributed to the control of malnutrition, along with measles vaccination and improvement in healthcare access. Various studies have concluded that massive dose vitamin A prophylaxis does not reduce childhood mortality; this may have been due to the Hawthorne effect; whereby beneficial effects arose from frequent contact of health workers with community members. Paradoxically, harmful effects of massive doses of Vit-A are documented, e.g. acute toxicity in certain groups of children, ranging from increased intracranial pressure, mental retardation (postnatal period), and even death. Vit-A also intensifies bone demineralization, and increased levels can lead to calcium deficiency and, hence, growth retardation in vulnerable children. According to the present authors, for children who have Bitot's spots or who have just recovered from an attack of measles, the best approach is to give Vit-A in therapeutic doses along with adequate daily intake of vegetables and fruits. Public-spirited citizens, along with the scientific community, must ensure the scrapping of the universal massive dose Vit-A prophylaxis approach, to avoid Vit-A toxicity and reduce economic burden to the health system.

Zinc supplementation for the prevention of pneumonia in children aged 2 months to 59 months

BACKGROUND

Pneumonia is a leading cause of morbidity and mortality in children younger than five years of age. Most deaths occur during infancy and in low-income countries. Daily zinc supplements have been reported to prevent acute lower respiratory tract infection (LRTI) and reduce child mortality. This is an update of a review first published in 2010.

OBJECTIVES

To evaluate the effectiveness of zinc supplementation in the prevention of pneumonia in children aged two to 59 months.

SEARCH METHODS

We searched CENTRAL (Issue 21 October 2016), MEDLINE (1966 to October 2016), Embase (1974 to October 2016), LILACS (1982 to October 2016), CINAHL (1981 to October 2016), Web of Science (1985 to October 2016) and IMSEAR (1980 to October 2016).

SELECTION CRITERIA

Randomised controlled trials (RCTs) evaluating zinc supplementation for the prevention of pneumonia in children aged from 2 months to 59 months.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data.

MAIN RESULTS

We did not identify any new studies for inclusion in this update. We included six studies that involved 5193 participants.Analysis showed that zinc supplementation reduced the incidence of pneumonia by 13% (fixed-effect risk ratio (RR) 0.87; 95% confidence interval (CI) 0.81 to 0.94, six studies, low-quality evidence) and prevalence of pneumonia by 41% (random-effects RR 0.59; 95% CI 0.35 to 0.99, one study, n = 609, low-quality evidence). On subgroup analysis, we found that zinc reduced the incidence of pneumonia defined by specific clinical criteria by 21% (i.e. confirmation by chest examination or chest radiograph) (fixed-effect RR 0.79; 95% CI 0.0.71 to 0.88, four studies, n = 3261), but had no effect on lower specificity pneumonia case definition (i.e. age-specific fast breathing with or without lower chest indrawing) (fixed-effect RR 0.95; 95% CI 0.86 to 1.06, four studies, n = 1932).

AUTHORS' CONCLUSIONS

Zinc supplementation in children is associated with a reduction in the incidence and prevalence of pneumonia.

An evidence-based systematic review of vitamin A by the natural standard research collaboration

An evidence-based systematic review of vitamin A by the Natural Standard Research Collaboration consolidates the safety and efficacy data available in the scientific literature using a validated and reproducible grading rationale. This paper includes written and statistical analysis of clinical trials, plus a compilation of expert opinion, folkloric precedent, history, pharmacology, kinetics/dynamics, interactions, adverse effects, toxicology, and dosing.

The historical evolution of thought regarding multiple micronutrient nutrition

Multiple micronutrient nutrition is an idea that originated in the 1940s and exemplifies the iterative nutritional paradigm. In the first four decades of the 20th century, scientists sought to separate and characterize the vitamins that were responsible for xerophthalmia, rickets, pellagra, scurvy, and beriberi. The dietary requirements of the different micronutrients began to be established in the early 1940s. Surveys showed that multiple micronutrient deficiencies were widespread in industrialized countries, and the problem was addressed by use of cod-liver oil, iodized salt, fortified margarine, and flour fortification with multiple micronutrients, and, with rising living standards, the increased availability and consumption of animal source foods. After World War II, surveys showed that multiple micronutrient deficiencies were widespread in developing countries. Approaches to the elimination of multiple micronutrient deficiencies include periodic vitamin A supplementation, iodized salt, targeted iron/folate supplementation, fortified flour, other fortified foods, home fortification with micronutrient powders, and homestead food production. The prevention of multiple micronutrient malnutrition is a key factor in achieving the Millennium Development Goals, given the important effects of micronutrients on health and survival.

The reality of pediatric emergency mass critical care in the developing world

INTRODUCTION

Public health emergencies resulting from major man-made crises and large-scale natural disasters severely impact developing countries, causing unprecedented rates of indirect mortality and morbidity, especially in children and women. Concomitantly, the state of children's health in the least-developed countries is the worst since the 1950s before the Declaration of Alma Ata. Worldwide decline in public health protections, infrastructures, and systems, and a health worker crisis primarily in Africa and Asia, limit the delivery of intensive and critical care services.

METHODS

In May 2008, the Task Force for Mass Critical Care published guidance on provision of mass critical care to adults. Acknowledging that the critical care needs of children during disasters were unaddressed by this effort, a 17-member Steering Committee, assembled by the Oak Ridge Institute for Science and Education with guidance from members of the American Academy of Pediatrics, convened in April 2009 to determine priority topic areas for pediatric emergency mass critical care recommendations.Steering Committee members established subgroups by topic area and performed literature reviews of MEDLINE and Ovid databases. The Steering Committee produced draft outlines through consensus-based study of the literature and convened October 6-7, 2009, in New York, NY, to review and revise each outline. Eight draft documents were subsequently developed from the revised outlines as well as through searches of MEDLINE updated through March 2010.The Pediatric Emergency Mass Critical Care Task Force, composed of 36 experts from diverse public health, medical, and disaster response fields, convened in Atlanta, GA, on March 29-30, 2010. Feedback on each manuscript was compiled and the Steering Committee revised each document to reflect expert input in addition to the most current medical literature.

TASK FORCE RECOMMENDATIONS

Using pandemics as a model of public health emergencies, steps to improve care to the most vulnerable of populations are outlined, including mandates under the International Health Regulations Treaty of 2007 and World Health Organization guidelines. Recommendations include an emphasis on first improving primary care, prevention, and basic emergency care, where possible. Advances in care should move incrementally without compromising primary care resources. A first step in preparing for a pandemic in developing countries involves building capacity in public health surveillance and proven community containment and mitigation strategies. Given the severe lack of healthcare workers in at least 57 countries, the Task Force also supports World Health Organization's recommendations that planning for a public health emergency include means for health workers to collaborate with staff in the military, transport, and education sectors as well as international healthcare workers to maximize the efficiency of scarce human resources. Rapid response teams can be augmented by international subject matter experts if these do not exist at the country level.

Zinc supplementation for the prevention of pneumonia in children aged 2 months to 59 months

BACKGROUND

Pneumonia is a leading cause of morbidity and mortality in children younger than five years of age. Most deaths occur during infancy and in low-income countries. Daily regimens of zinc have been reported to prevent acute lower respiratory tract infection and reduce child mortality.

OBJECTIVES

To evaluate the effectiveness of zinc supplementation in the prevention of pneumonia in children aged two to 59 months.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2010, Issue 2), which contains the Acute Respiratory Infections Group's Specialised Register, MEDLINE (1966 to January Week 2, 2010), EMBASE (1974 to January 2010) and LILACS (1985 to January 2010).

SELECTION CRITERIA

Randomised controlled trials (RCTs) evaluating supplementation of zinc for the prevention of pneumonia in children aged 2 to 59 months of age.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data.

MAIN RESULTS

We included six trials and 7850 participants in the meta-analysis. Analysis showed that zinc supplementation reduced the incidence of pneumonia by 13% (risk ratio (RR) 0.87; 95% confidence interval (CI) 0.81 to 0.94, fixed-effect, six studies) and prevalence of pneumonia by 41% (RR 0.59; 95% CI 0.35 to 0.99, random-effects, one study). On subgroup analysis, we found that zinc reduced the incidence of pneumonia defined by specific clinical criteria by 21% (i.e. confirmation by chest examination or chest radiograph) (RR 0.79; 95% CI 0.0.71 to 0.88, fixed-effect, four studies, n = 4591) but had no effect on lower specificity pneumonia case definition (i.e. age specific fast breathing with or without lower chest indrawing) (RR 0.95; 95% CI 0.86 to 1.06, fixed-effect, four studies, n = 3259).

AUTHORS' CONCLUSIONS

Zinc supplementation in children is associated with a reduction in the incidence and prevalence of pneumonia, the leading cause of death in children.

Regression splines in the time-dependent coefficient rates model for recurrent event data

Many epidemiologic studies involve the occurrence of recurrent events and much attention has been given for the development of modeling techniques that take into account the dependence structure of multiple event data. This paper presents a time-dependent coefficient rates model that incorporates regression splines in its estimation procedure. Such methods would be appropriate in situations where the effect of an exposure or covariates changes over time in recurrent event data settings. The finite sample properties of the estimators are studied via simulation. Using data from a randomized community trial that was designed to evaluate the effect of vitamin A supplementation on recurrent diarrheal episodes in small children, we model the functional form of the treatment effect on the time to the occurrence of diarrhea. The results describe how this effect varies over time. In summary, we observed a major impact of the vitamin A supplementation on diarrhea after 2 months of the dosage, with the effect diminishing after the third dosage. The proposed method can be viewed as a flexible alternative to the marginal rates model with constant effect in situations where the effect of interest may vary over time.

The role of retinol in the etiology and outcome of suppurative otitis media

Vitamin A deficiency is still a serious public health problem affecting an estimated 127 million preschool children. The resulting immunological dysfunctions lead to increased risks of respiratory tract infections, diarrhoeal diseases and blindness, among others. The aim of this study is to determine the significance of the role of serum retinol in the etiology of acute suppurative otitis media (ASOM) and its chronicity (CSOM). In a prospective follow-up of patients with ASOM for 6-9 months, serum retinol determination was done using the high performance liquid chromatography. Participants comprised 358 ASOM and 52 control subjects. Six-month follow-up was achieved in 264 subjects (74%); of these, there was persistence of otorrhoea (CSOM) in 116, while 148 had resolved ASOM. Of the 264 subjects, 146 were males and 118 were females, between the ages of 6 months and 9 years and a mean of 7 years (SD = 2.32), whereas the control subjects comprised 29 males and 22 females, between the ages of 6 months and 11 years and a mean of 7.8 years (SD = 3.6). The range of serum retinol in the ASOM subjects was 1.63-2.64 microg/L, mean of 1.53 microg/L, median value of 2.61 microg/L and (SD = 0.16). Among control subjects, the range was 2.5-2.8 microg/L, mean of 2.58 microg/L and median value of 2.61 microg/L (SD = 0.14) (Table 1). The range of serum retinol in the resolved ASOM subjects was 1.61-2.63 microg/L, mean of 2.07 microg/L and median value of 2.09 microg/L (SD = 0.16) while the CSOM subjects ranged between 0.8-2.86 microg/L, mean of 1.58 microg/L and median value of 1.28 microg/L, (SD = 0.48) (Table 2). Univariate analysis using unpaired t test to compare the mean serum retinol revealed significant difference between ASOM and control (P = 0.0000) and between resolved ASOM and CSOM (P = 0.0000). In conclusion, hyporetinolaemia was a significant etiological factor in the etiology ASOM and CSOM, suggesting retinol supplementation as one strategy in control of SOM.

Vitamin A for preventing acute lower respiratory tract infections in children up to seven years of age

BACKGROUND

Vitamin A supplements are effective for preventing diarrhoea. There are theoretical reasons it might also be effective for acute lower respiratory tract infections (LRTIs), also very common in children, especially in low income countries.

OBJECTIVES

To assess the effectiveness and safety of vitamin A for preventing acute LRTIs in children up to seven years of age.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2007, Issue 2); MEDLINE (1966 to July 2007); EMBASE (1974 to July 2007); and the Chinese Biomedicine Database (CBM) (1976 to July 2007).

SELECTION CRITERIA

Randomised controlled trials (RCTs) that assessed the effectiveness of vitamin A in the prevention of acute LRTI in children up to seven years of age.

DATA COLLECTION AND ANALYSIS

The review authors independently extracted data and assessed trial quality. Study authors were contacted for additional information.

MAIN RESULTS

Most studies found no significant effect of vitamin A on the incidence of acute LRTI, or prevalence of symptoms of acute LRTI. Vitamin A caused an increased incidence of acute LRTI in one study; an increase in cough and fever; and increased symptoms of cough and rapid breathing in two others. Three reported no differences and no protective effect of vitamin A. Two studies reported that vitamin A significantly reduced the incidence of acute LRTI with children with poor nutritional status or weight, but increased it in normal children.

AUTHORS' CONCLUSIONS

This unexpected result is outside our current understanding of the use of vitamin A for preventing acute LRTIs. Accordingly, vitamin A should not be given to all children to prevent acute LRTIs. There is evidence for vitamin A supplements to prevent acute LRTIs in children with low serum retinol or those with a poor nutritional status.

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.

Retinyl palmitate supplementation by inhalation of an aerosol improves vitamin A status of preschool children in Gondar (Ethiopia)

We report successful vitamin A supplementation by inhalation of retinyl palmitate in a placebo-controlled pilot study in twenty-five preschool children (2–5 years of age) in the rural district of Gondar, Ethiopia. Preschool children (n 161) were randomly selected from 220 households. Out of this cohort, twenty-five children were randomly assigned to each of two treatment groups: one receiving retinyl palmitate by inhalation of two puffs of an aerosol containing 1 mg (3000 IU) per delivery to give a total of 2 mg (6000 IU); and the other receiving an aerosol without retinyl palmitate. Both treatments were administered every 2 weeks for 3 months. Serum retinol and retinol-binding protein concentrations in the vitamin A-treated group were 0·68 (sd 0·31) μmol/l and 59·4 (sd 24·2) mg/l before and 1·43 (sd 0·46) μmol/l (P < 0·01) and 97·3 (sd 31·2) mg/l (P < 0·05) 3 months after supplementation with retinyl palmitate, suggesting that this novel method of delivery of retinyl palmitate by inhalation is effective in improving vitamin A status.

A double-blind, randomized, clinical trial of the effect of vitamin A and zinc supplementation on diarrheal disease and respiratory tract infections in children in Mexico City, Mexico

BACKGROUND

The efficacy of micronutrient supplementation in improving childhood health and survival in developing countries may be specific to the micronutrient used and health outcome measured.

OBJECTIVE

We evaluated the effect of vitamin A and zinc supplementation on overall rates of childhood diarrheal disease and respiratory tract infections and rates stratified by household and personal characteristics.

DESIGN

A double-blind, randomized, placebo-controlled trial was carried out in which 736 children aged 6-15 mo living in a periurban area of Mexico City were assigned to receive vitamin A every 2 mo, zinc daily, vitamin A and zinc together, or placebo. Children were followed for 12 mo to determine overall counts of diarrheal episodes and respiratory tract infections.

RESULTS

Vitamin A supplementation was associated with a 27% increase in diarrheal disease [risk ratio (RR): 1.27; 95% CI: 1.10, 1.45; P < 0.001] and a 23% increase in cough with fever (RR: 1.23; 95% CI: 1.02, 1.47; P = 0.02), whereas zinc had no effect on these outcomes. Vitamin A supplementation decreased diarrhea in children from households with dirt floors but increased diarrhea in children from households with nondirt floors, piped water, and indoor bathrooms. Zinc supplementation decreased diarrhea in children from households with dirt floors and whose mothers were more educated. Vitamin A supplementation increased cough with fever in children from less-crowded households that lacked indoor bathrooms and in children of less-educated mothers.

CONCLUSIONS

Vitamin A increases diarrheal disease and respiratory tract infections in young children in periurban areas of Mexico City. Vitamin A and zinc have more heterogeneous effects in different subgroups of children.

Vitamin A for non-measles pneumonia in children

BACKGROUND

Acute respiratory infections, mostly in the form of pneumonia, are the leading causes of death in children under five years of age in developing countries. Some clinical trials have demonstrated that vitamin A supplementation reduces the severity of respiratory infection and mortality in children with measles.

OBJECTIVES

To determine whether adjunctive vitamin A is effective in infants and children diagnosed with non-measles pneumonia.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 4, 2004); MEDLINE (1996 to November Week 3, 2004); EMBASE (1990 to September 2004); LILACS (9 January 2004); CINAHL (1990 to November 2004); Biological Abstracts (1990 to November 2004) and Current Contents (1990 to September 2004); and the Chinese Biomedicine Database (CBM) (1994 to November 2004).

SELECTION CRITERIA

Only parallel-arm, randomised and quasi-randomised controlled trials in which children (younger than 15 years old) with non-measles pneumonia were treated with adjunctive vitamin A were included.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and assessed trial quality. Study authors were contacted for additional information.

MAIN RESULTS

Five trials involving 1453 infants and children were included. There was no significant reduction in the mortality associated with pneumonia in children treated with vitamin A compared to those who were not (pooled odds ratio (OR) 1.49; 95% confidence interval (CI) 0.66 to 3.35). In addition, there was a lack of a statistically significant effect on duration of stay in hospital (weighted mean difference (WMD) 0.08; 95% CI -0.43 to 0.59). Vitamin A was associated with a 39% reduction in antibiotic firstline failure (OR 0.65; 95% CI 0.42 to 1.01). Children receiving vitamin A were no more likely to experience vomiting (OR 0.77; 95% CI 0.45 to 1.33), diarrhoea (OR 0.57; 95% CI 0.31 to 1.05), bulging of the fontanelles (OR 8.25; 95% CI 0.44 to 155.37) or irritability (OR 0.93, 95% CI 0.56 to 1.57) than those not receiving vitamin A. There was no statistical significance between vitamin A and placebo groups (OR 0.90; 95% CI -1.10 to 2.90) in chest x-ray results. Disease severity after supplementary high-dose vitamin A was significantly worse in children who received vitamin A compared with placebo. Low-dose vitamin A was associated with a significant reduction in the recurrent rate of bronchopneumonia (OR 0.12; 95% CI 0.03 to 0.46).

AUTHORS' CONCLUSIONS

The evidence did not suggest a significant reduction with vitamin A adjunctive treatment in mortality, measures of morbidity, nor an effect on the clinical course of pneumonia in children with non-measles pneumonia. However, not all studies measured all outcomes, limiting the number of studies that could be incorporated into the meta-analyses, so that there may have been a lack of statistical power to detect statistically significant differences.

Respiratory tract infections in children in developing countries

Acute respiratory infections are the main cause of morbidity worldwide, and pneumonia represents one of the main causes of death in children younger than the age of 5 years in developing countries. Several risk factors for acquiring respiratory infections in developing countries, such as poverty, restricted family income, low parental education level, low birth weight, malnutrition, and lack of breastfeeding, have been described. Another important factor in recent years that has aggravated the problem of acute respiratory infections in developing countries is the human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) pandemic. In developing countries, identifying the etiology is difficult and World Health Organization recommends making the diagnosis of pneumonia based on clinical parameters. The diagnosis and suitable treatment administered by primary healthcare workers, particularly in rural areas, is part of the strategy to prevent mortality. Finally, it is important that industrialized countries support the economic growth of the developing countries to improve their healthcare system and to ensure that performed research studies will give benefits to their populations.

Evaluation of hospitalisation for indigenous children with malnutrition living in central Australia

OBJECTIVE

To evaluate the effectiveness of hospital admissions for indigenous children with malnutrition in a rural/remote Australian centre.

DESIGN

Retrospective review of the medical records.

SETTING

Rural secondary hospital.

SUBJECTS

Remote and rural indigenous children aged less than four years managed for malnutrition in Alice Springs Hospital (ASH).

MAIN OUTCOME MEASURE

The primary outcome measure was weight gain during hospitalisation and posthospitalisation. Secondary outcome measures were yield of investigations, diagnoses made, treatments given, social interventions, readmission rate and nosocomial infection.

RESULTS

Median age of the 55 children was 15.1 months. Median weight change was 1.5 g day(-1)prior to hospitalisation, 36.7 g day(-1)during and 9 g day(-1)two months following hospitalisation (P < 0.05). Investigations performed had high yields (80% of children had a treatable organic contributor to malnutrition). Nosocomial infection occurred in 21 (38%) children. Readmission occurred at an average of 1.9 times per child (range 0-5), 34 (37%) occurred within three months and 48 (52%) within six months.

CONCLUSION

In rural Indigenous children with malnutrition, hospitalisation was effective in re-establishing growth and defining organic contributors to malnutrition. However, the high readmission rate and nosocomial infection mandates that alternative models to nutritional rehabilitation, in addition to a broad psychosocial and public health approach to prevention and management of malnutrition, is required.

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.

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.

Extent of vitamin A deficiency among preschool children and women of reproductive age

Knowledge of the extent of vitamin A (VA) deficiency (D) is critical for identifying high-risk populations and mobilizing resources for prevention. Yet, all estimates are necessarily imperfect, often based on assumptions in the absence of data. In 1995, the World Health Organization estimated 254 million children to be VA-deficient and 2.8 million to have xerophthalmia. Subsequently, estimates were changed to 75-140 million and 3.3 million, respectively. Although both sets are consistent with a problem of enormous magnitude, the discrepancies also created uncertainty. The present analysis indicates there are approximately 127 million and 4.4 million preschool children with VAD (serum retinol < 0.70 micro mol/L or displaying abnormal impression cytology) and xerophthalmia, respectively. More than 7.2 million pregnant women in the developing world are VA-deficient (serum or breast-milk vitamin A concentrations < 0.70 micro mol/L), and another 13.5 million have low VA status (0.70-1.05 micro mol/L); >6 million women develop night blindness (XN) during pregnancy annually. Roughly 45% of VA-deficient and xerophthalmic children and pregnant women with low-to-deficient VA status live in South and Southeast Asia. These regions harbor >60% of all cases of maternal XN, three fourths of whom seem to live in India. Africa accounts for 25-35% of the global cases of child and maternal VAD; about 10% of all deficient persons live in the eastern Mediterranean region, 5-15% live in the Western Pacific and approximately 5% live in the Region of the Americas. VA prophylaxis seems to be preventing the number of deficient preschool children from increasing while probably reducing rates of blindness and mortality. Greater effort is needed to assess and prevent VAD and its disorders, particularly among pregnant and lactating women.

Feeding of red palm oil-supplemented diets to rats may impact positively on vitamin A status

The impact of feeding of dietary palm oil supplements on plasma vitamin A profile was investigated in animals. Four-week-old Wistar albino rats (n = 8 per group) were maintained for 28 days on standard rat food (4.7% fat by weight) supplemented (10%, 20% and 30% by weight) with red palm oil (RPO) and refined palm olein (REFPO). Plasma beta-carotene and vitamin A concentrations of rats fed RPO-based diets were higher than in rats fed REFPO and control diets. Animals fed 30% RPO-containing diets had lower plasma beta-carotene concentrations than those fed 20% RPO-containing diets. The results suggest that consumption of palm oil in moderate amounts enhances growth of tissues and bioavailability of beta-carotene, which may combat vitamin A deficiency in developing countries, in view of the fact that performed vitamin A in animal products (namely meat, liver, eggs and fatty fish) is out of the reach of economically deprived people.

Substantial reduction in severe diarrheal morbidity by daily zinc supplementation in young north Indian children

OBJECTIVE

To evaluate the impact of 4 months of daily zinc supplementation on the incidence of severe and recurrent diarrhea in children 6 to 30 months of age.

METHODS

A double-blind, randomized, placebo-controlled trial was conducted on children who were identified by a door-to-door survey to be aged 6 to 30 months and residing in the urban slum of Dakshinpuri, New Delhi. They were randomized to receive daily zinc gluconate (elemental zinc 10 mg to infants and 20 mg to older children) or placebo. A field attendant administered the syrup daily at home for 4 months except on Sundays, when the mother did so. One bottle that contained 250 mL was kept in the child's home and replaced monthly. Field workers visited households every seventh day during the 4-month follow-up period. At each visit, information was obtained for the previous 7 days on history of fever, number and consistency of stools, and presence of cough. When the child was ill, illness characteristics and treatment seeking outside the home were determined. If the child had diarrhea or vomiting, then dehydration was assessed. At household visits, 2 packets of oral rehydration salts were given when a child had diarrhea. Children who visited the study clinic spontaneously for illness or were referred by the field workers were treated according to the standard national program guidelines. Antibiotics were advised only for diarrhea with bloody stools or for associated illnesses. For using generalized estimating equations for longitudinal analysis of a recurring event such as diarrhea, the follow-up data for each child was divided into 17 child-periods of 7 days each and presence or absence of an incident episode of diarrhea or severe diarrhea within each 7-day period was coded. This method of analysis does not assume independence of events and therefore prevents underestimation of variance that results because of correlation of morbidity within the same child. A logistic generalized estimating equations model with exchangeable correlation covariance-variance matrix was then used to estimate the effect size.

RESULTS

Zinc or placebo doses were administered on 88.8% and 91.2%, respectively, of study days during the 4 months of follow-up. There was a small but significant increase in the average number of days with vomiting in the zinc group (4.3 [standard deviation (SD): 5.8] vs 2.6 [SD 3.9] days; difference in means: 1.7 [95% confidence interval (CI): 1.3-2.1] days). At the baseline, mean plasma zinc was 62.0 microg/dL (SD: 14.3 microg/dL) in the zinc and 62.0 microg/dL (SD: 11.2 microg/dL) in the placebo group; 45.8% and 42%, respectively, had low plasma zinc levels below 60 microg/dL. At the end of the study, plasma zinc levels were substantially higher in the zinc group (ratio of geometric means: 1.94 [95% CI: 1.86-2.03]) and the proportion with low plasma zinc was lower (difference in proportions: -46.7% [95% CI: -41.8% to -51.4%]). The incidence of diarrhea during follow-up was lower in the zinc-supplemented as compared with the placebo group (odds ratio [OR]: 0.88; 95% CI: 0.82-0.95). The beneficial impact of zinc was greater on the incidence of diarrhea with progressively increasing duration: episodes of diarrhea that lasted 1 to 6 days (OR: 0.92; 95% CI: 0.85-1.00), 7 to 13 days (OR: 0.79; 95% CI: 0.65-0.95), and > or =14 days (OR: 0.69; 95% CI: 0.48-0.98). The impact was also greater on the incidence of episodes with progressively higher stool frequency: 3 to 5 stools per day (OR: 0.90; 95% CI: 0.83-0.98), 6 to 9 stools per day (OR: 0.87; 95% CI: 0.77-0.98), and > or =10 per day (OR: 0.77; 95% CI: 0.63-0.94). In the zinc group, significantly more children experienced no diarrheal episode during the study period (risk ratio [RR]: 1.22; 95% CI: 1.02-1.44). Furthermore, substantially fewer children (RR: 0.51; 95% CI: 0.36-0.73) experienced recurrent diarrhea, defined as >6 diarrheal episodes in the follow-up period as compared with children in the placebo group. The number of children who were hospitalized for any cause tended to be lower in the zinc group, but the difference was not statistically significant (1.79% vs 2.43%; RR: 0.74; 95% CI: 0.43-1.27). The baseline mean plasma copper (microg/dL) was similar in the 2 groups (difference in means: 1.6; 95% CI: -2.9 to 6.1). The end study plasma copper levels were significantly lower in the zinc group (difference in means: -15.5; 95% CI: -19.9 to - 11.1).

CONCLUSIONS

Zinc supplementation substantially reduced the incidence of severe and prolonged diarrhea, the 2 important determinants of diarrhea-related mortality and malnutrition. This intervention also substantially reduced the proportion of children who experienced recurrent diarrhea. Prompt measures to improve zinc status of deficient populations are warranted. The potential approaches to achieve this goal include food fortification, dietary diversification, cultivation of plants that are zinc dense or have a decreased concentration of zinc absorption inhibitors, and supplementation of selected groups of children. Future studies should assess the impact of increased zinc intakes on childhood mortality in developing countries. For facilitating intervention, there is a need to obtain reliable estimates of zinc deficiency, particularly in developing countries. The functional consequences of the effect of various doses of zinc on plasma copper levels merits additional study.

Protective nutrients and functional foods for the gastrointestinal tract

Epithelial and other cells of the gastrointestinal mucosa rely on both luminal and bloodstream sources for their nutrition. The term functional food is used to describe nutrients that have an effect on physiologic processes that is separate from their established nutritional function, and some of these nutrients are proposed to promote gastrointestinal mucosal integrity. We review the recent in vitro, animal, and clinical experiments that evaluated the role of several types of gastrointestinal functional foods, including the amino acids glutamine and arginine, the essential micronutrients vitamin A and zinc, and 2 classes of food additives, prebiotics and probiotics. Many of the data from preclinical studies support a strong role for enteral nutrients in gastrointestinal health; in comparison, the data from human studies are limited. In some cases, impressive data from in vitro and animal studies have not been replicated in human trials. Other clinical trials have shown positive health benefits, but some of those studies were plagued by flaws in study design or analysis. The methods available to detect important changes in human gastrointestinal function and structure are still limited, but with the development of more sensitive measures of gastrointestinal function, the effects of specific nutrients may be more easily detected. This may facilitate the development of phase 3 clinical trials designed to more rigorously evaluate the effects of a particular nutrient by focusing on valid and reliable outcome measures. Regulatory changes in the way in which health claims can be made for dietary supplements should also be encouraged.

Effect of vitamin A administered at Expanded Program on Immunization contacts on antibody response to oral polio vaccine

OBJECTIVE

Vitamin A supplementation to mothers in the postpartum period and to their infants at routine immunization contacts is being considered to reduce vitamin A deficiency in infancy. This study was conducted to determine the impact of maternal and infant vitamin A supplementation on antibody response to oral polio vaccine (OPV).

DESIGN

Randomized, double blind, placebo-controlled trial.

INTERVENTIONS

Mothers in the intervention group received 60 mg retinol equivalent (RE) vitamin A 3-4 weeks after delivery and their infants 7.5 mg RE with each OPV dose at 6, 10 and 14 weeks of age. The control group mothers and their infants received a placebo at each of these contacts.

MAIN OUTCOMES

Geometric mean (GM) titer of neutralizing antibodies and proportion of children with protective titer to the three polioviruses at 26 weeks of age.

RESULTS

Vitamin A supplementation increased the proportion of infants with protective antibody titer against poliovirus type 1 (relative risk (RR) 1.15, 95% confidence interval (CI) 1.03-1.28) and the GM antibody titer (ratio of GM 1.55, 95% CI 1.03-2.31) following immunization. The proportion of infants with protective antibody titer against poliovirus type 2 (RR 0.99, 95% CI 0.94-1.05) or type 3 (RR 1.05, 95% CI 0.96-1.15) was not significantly different in vitamin A and placebo groups. The GM antibody titer for poliovirus type 2 (ratio of GM 0.99, 95% CI 0.64-1.54) or poliovirus type 3 (ratio of GM 1.10, 95% CI 0.69-1.75) also did not differ across groups.

CONCLUSIONS

Vitamin A given to the mothers in the postpartum period and their infants with OPV did not interfere with the antibody response to any of the three polioviruses and enhanced the response to poliovirus type 1.

Suplementação com vitamina A: impacto na morbidade e efeitos adversos

Este artigo apresenta uma síntese de dois estudos previamente publicados e que avaliaram diferentes aspectos dos efeitos da suplementação com mega-doses (100.000 ou 200.000 UI) de vitamina A em crianças pré-escolares. O primeiro é um ensaio comunitário, aleatório, duplo cego e placebo controlado, que demonstrou o efeito positivo da suplementação na redução da severidade dos episódios de diarréia. O segundo investigou os potenciais efeitos adversos da suplementação com mega-doses de vitamina A, oferecida conjuntamente com a vacinação em massa, utilizando um desenho de intervenção controlado e não randomizado. Seus resultados indicaram que a suplementação associada com as vacinas rotineiramente utilizadas na infância não elevou as taxas de efeitos adversos (diarréia, febre e vômito). São ainda discutidas as implicações dos resultados destes estudos, que contribuíram não somente para o avanço do conhecimento científico do campo em questão, como também têm fornecido evidências para justificar a implementação de políticas e ações específicas no campo da saúde e da nutrição, que por sua vez têm contribuído para gerar condições mais auspiciosas de sobrevivência na infância. Discute-se também a pertinência e a utilidade de desenhos de estudo com diferentes níveis de rigor metodológico na avaliação de intervenção em saúde.

Vitamin A, infection, and immune function

In populations where vitamin A availability from food is low, infectious diseases can precipitate vitamin A deficiency by decreasing intake, decreasing absorption, and increasing excretion. Infectious diseases that induce the acute-phase response also impair the assessment of vitamin A status by transiently depressing serum retinol concentrations. Vitamin A deficiency impairs innate immunity by impeding normal regeneration of mucosal barriers damaged by infection, and by diminishing the function of neutrophils, macrophages, and natural killer cells. Vitamin A is also required for adaptive immunity and plays a role in the development of T both-helper (Th) cells and B-cells. In particular, vitamin A deficiency diminishes antibody-mediated responses directed by Th2 cells, although some aspects of Th1-mediated immunity are also diminished. These changes in mucosal epithelial regeneration and immune function presumably account for the increased mortality seen in vitamin A-deficient infants, young children, and pregnant women in many areas of the world today.

Micronutrients and child health: studies in international nutrition and HIV infection

Increasing data link micronutrient deficiencies to excess childhood morbidity and mortality, and similar relationships have been noted in the study of nutrition and HIV infection. We review epidemiologic studies that have examined the relationship between micronutrient deficiencies and health outcomes in childhood and HIV infection, as well as clinical trials of micronutrient supplementation. Vitamin A supplementation among communities at risk of deficiency effectively reduces mortality and morbidity in children younger than age 5, and vitamin A may be especially effective in HIV-infected children. Vertical transmission of HIV has not to date been affected by maternal micronutrient supplementation. In children with poor dietary zinc intake and/or bioavailability, zinc supplementation reduces the incidence and severity of diarrheal diseases, as well as the occurrence of pneumonia. Vitamin A therapy has not been associated with improved growth, whereas some trials have shown that zinc supplementation is associated with greater increments in height. Further trials of micronutrient supplementation are warranted.

Simultaneous zinc and vitamin A supplementation in Bangladeshi children: randomised double blind controlled trial

OBJECTIVE

To evaluate the effect of simultaneous zinc and vitamin A supplementation on diarrhoea and acute lower respiratory infections in children.

STUDY DESIGN

Randomised double blind placebo controlled trial.

SETTING

Urban slums of Dhaka, Bangladesh.

PARTICIPANTS AND METHODS

800 children aged 12-35 months were randomly assigned to one of four intervention groups: 20 mg zinc once daily for 14 days; 200 000 IU vitamin A, single dose on day 14; both zinc and vitamin A; placebo. The children were followed up once a week for six months, and morbidity information was collected.

RESULTS

The incidence and prevalence of diarrhoea were lower in the zinc and vitamin A groups than in the placebo group. Zinc and vitamin A interaction had a rate ratio (95% confidence interval) of 0.79 (0.66 to 0.94) for the prevalence of persistent diarrhoea and 0.80 (0.67 to 0.95) for dysentery. Incidence (1.62; 1.16 to 2.25) and prevalence (2.07; 1.76 to 2.44) of acute lower respiratory infection were significantly higher in the zinc group than in the placebo group. The interaction term had rate ratios of 0.75 (0.46 to 1.20) for incidence and 0.58 (0.46 to 0.73) for prevalence of acute lower respiratory infection.

CONCLUSIONS

Combined zinc and vitamin A synergistically reduced the prevalence of persistent diarrhoea and dysentery. Zinc was associated with a significant increase in acute lower respiratory infection, but this adverse effect was reduced by the interaction between zinc and vitamin A.

Food supplementation with encouragement to feed it to infants from 4 to 12 months of age has a small impact on weight gain

It is unclear whether a substantial decline in malnutrition among infants in developing countries can be achieved by increasing food availability and nutrition counseling without concurrent morbidity-reducing interventions. The study was designed to determine whether provision of generous amounts of a micronutrient-fortified food supplement supported by counseling or nutritional counseling alone would significantly improve physical growth between 4 and 12 mo of age. In a controlled trial, 418 infants 4 mo of age were individually randomized to one of the four groups and followed until 12 mo of age. The first group received a milk-based cereal and nutritional counseling; the second group monthly nutritional counseling alone. To control for the effect of twice-weekly home visits for morbidity ascertainment, similar visits were made in one of the control groups (visitation group); the fourth group received no intervention. The median energy intake from nonbreast milk sources was higher in the food supplementation group than in the visitation group by 1212 kJ at 26 wk (P < 0.001), 1739 kJ at 38 wk (P < 0.001) and 2257 kJ at 52 wk (P < 0.001). The food supplementation infants gained 250 g (95% confidence interval: 20--480 g) more weight than did the visitation group. The difference in the mean increment in length during the study was 0.4 cm (95% confidence interval: -0.1--0.9 cm). The nutritional counseling group had higher energy intakes ranging from 280 to 752 kJ at different ages (P < 0.05 at all ages) but no significant benefit on weight and length increments. Methods to enhance the impact of these interventions need to be identified.

Vitamin A supplements and diarrheal and respiratory tract infections among children in Dar es Salaam, Tanzania

OBJECTIVE

To determine the effect of vitamin A supplementation on the risk of diarrhea and of acute respiratory infection.

DESIGN

Double-blind, randomized, placebo-controlled trial.

SETTING

Dar-es-Salaam, Tanzania.

SUBJECTS

Six hundred eighty-seven children, 6 to 60 months old, hospitalized with pneumonia, who received vitamin A or placebo at baseline and at 4 and 8 months after discharge from hospital.

MAIN OUTCOME VARIABLES

Incidence and duration of episodes of diarrhea and respiratory tract infections during the year after discharge from the hospital.

RESULTS

Relative to those receiving placebo, children receiving vitamin A had a significantly smaller risk of severe watery diarrhea (multivariate odds ratio = 0.56, 95% CI = 0.32-0.99, P =.04) but a higher risk of cough and rapid respiratory rate (multivariate odds ratio = 1.67, 95% CI = 1.17-2.36, P =.004). Vitamin A supplementation was also associated with increased risk of acute diarrhea among normally nourished children or children with stunted growth but was relatively protective among children with wasting disease (P value for interaction =.01). The apparently increased risk of respiratory tract infection was limited to children who were seronegative for human immunodeficiency virus (HIV) (P value for interaction =.07).

CONCLUSIONS

Vitamin A supplements provide a low-cost intervention against morbidity in HIV-infected and undernourished children. Supplements may also have serious non-lethal adverse outcomes in well-nourished individuals. Whether these apparent detrimental effects of vitamin A are transient or long-term needs to be examined.

Vitamin A supplementation: implications for morbidity and mortality in children

Vitamin A deficiency impairs epithelial integrity and systemic immunity and increases the incidence and severity of infections during childhood. However, findings from vitamin A supplementation trials are not consistent. Supplementation has resulted in significant reductions in mortality in several (but not all) large community-based trials among apparently healthy children. In hospital-based studies, vitamin A supplements have been consistently found to reduce the severity of measles infection, but no effect on nonmeasles respiratory infections has been observed. In some cases, the supplements were associated with an apparently increased risk of lower respiratory infection. Vitamin A supplements also reduced the severity of diarrhea in most (but not all) trials. Potential explanations for the differences in efficacy across trials are reviewed. While vitamin A supplementation is effective in reducing total mortality and complications from measles infections, it is likely to be more effective in populations suffering from nutritional deficiencies.

Malnutrition, morbidity and mortality in children and their mothers

While being underweight or stunted is recognized as an important risk factor for increased prevalence and severity of infection and high mortality rates, there is increasing evidence for an independent role for micronutrient deficiency. Improving vitamin A status reduces mortality among older infants and young children and reduces pregnancy-related mortality; it also reduces the prevalence of severe illness and clinic attendance among children. Improving Zn status reduces morbidity from diarrhoeal and respiratory infection. Treatment of established infection with vitamin A is effective in measles-associated complications, but is not as useful in the majority of diarrhoeal or respiratory syndromes. Zn supplements, however, have significant benefit on the clinical outcome of diarrhoeal and respiratory infections. Concerns that Fe supplements might increase morbidity if given in malarious populations appear to be decreasing, in the light of new studies on Fe supplements showing improved haemoglobin without an increase in morbidity. Breast-feeding, well known to protect against diarrhoea, is also important in protecting against respiratory infection, especially in the young infant. Transmission of human immunodeficiency virus (HIV) in breast milk is recognized, but new data showing reduced transmission in infants who receive exclusive breast-feeding rather than mixed feeding reinforces the importance of promoting this practice in areas where environmental contamination precludes the safe use of other infant feeding regimens. The presence of subclinical mastitis, now recognized to occur in approximately 20 % of mothers in several developing countries, has been shown to increase the concentration of HIV in breast milk. Preliminary findings suggest that the prevalence of subclinical mastitis is reduced by dietary supplements containing antioxidants. Governments and international agencies now have a strong scientific basis to be much more active and innovative in the introduction of focused nutrition interventions especially micronutrients, for the control of infection.

[Tolerance to administration of massive doses of vitamin A associated to mass immunization of children in Northeast Brazil]

A follow-up study was carried out in two localities in the semi-arid region of the State of Bahia, Northeast Brazil, with the aim of identifying the occurrence and nature of possible acute side effects subsequent to vitamin A megadose supplement given together with mass immunization in children 6-59 months old. The sample consisted of 852 children, 416 from the county of Teofilandia who received vitamin A together with vaccines and 436 from Santa Barbara, who received only vaccine. In the 24 hours before immunization, children from both groups had similar incidences of diarrhea, fever, and vomiting. Anorexia was more prevalent in Teofilandia and remained so throughout the study period. The results suggest that acute side effects like diarrhea, vomiting, fever, or anorexia were not associated with the vitamin A dosage given with mass OPV, DPT, and measles immunization.

A randomized trial of vitamin A supplements in relation to mortality among human immunodeficiency virus-infected and uninfected children in Tanzania

OBJECTIVES

To determine whether vitamin A supplements result in reduced mortality among HIV-infected and uninfected children.

DESIGN

Randomized, double blind, placebo-controlled trial.

METHODS

Starting in April, 1993, we randomized 687 children age 6 months to 5 years who were admitted to the hospital with pneumonia. Children who were severely malnourished or had clinical signs of vitamin A deficiency were excluded. At baseline children received placebo or 400 000 IU (or half that for infants) of vitamin A, in addition to standard treatment for pneumonia. They received further doses of the same regimen 4 and 8 months after hospital discharge. Sera from children were tested for HIV antibodies by enzyme-linked immunosorbent assay and Western blot tests. For positive children <15 months of age, HIV infection was confirmed by amplified heat-denatured HIV-p24 antigen assays with confirmatory neutralization assays. HIV status was ascertained for 648 of 687 enrolled children. The mean duration of follow-up was 24.4 months (SD = 12.1).

RESULTS

Of 648 children 58 (9%) were HIV-infected. Compared with uninfected children, all-cause mortality was higher among HIV-infected children, as was mortality caused by pneumonia or diarrhea (P < 0.001 for each). Overall vitamin A supplements resulted in a 49% reduction in mortality [relative risk (RR), 0.51; 95% confidence interval (CI), 0.29 to 0.90, P = 0.02]. Vitamin A supplements reduced all-cause mortality by 63% among HIV-infected children (RR 0.37; CI 0.14 to 0.95, P = 0.04) and by 42% among uninfected children (RR 0.58, CI 0.28 to 1.19, P = 0.14). Vitamin A supplements were also associated with a 68% reduction in AIDS-related deaths (P = 0.05) and a 92% reduction in diarrhea-related deaths (P = 0.01).

CONCLUSION

Vitamin A deficiency, which is common among children in many developing countries, is particularly severe among HIV-infected children. Our findings indicate that vitamin A supplements, a low cost intervention, reduce mortality of HIV-infected children.

High dose vitamin A supplementation in the course of pneumonia in Vietnamese children

We carried out a randomized, placebo-controlled, double-blinded trial to evaluate the effect on morbidity of high dose oral vitamin A, given on hospital admission to 592 children aged 1-59 months with moderate and severe pneumonia. Severely underweight children were not included, but 45% were moderately underweight. The vitamin A and placebo groups were comparable in baseline characteristics. Four patients died. Among all of the surviving children, no differences were found regarding mean time for normalization of fever, respiratory rate and time of hospitalization. Stratification for moderate malnutrition, degree of pneumonia, age and sex revealed moderately malnourished vitamin A-supplemented children to have a shorter time of hospitalization (p = 0.04), due to an effect in females aged > 12 months (p = 0.02) and females with very severe pneumonia (p = 0.048). This study indicates that, in developing countries like Vietnam, supplementation with vitamin A in children with pneumonia could shorten the recovery rate in the ones that are undernourished, especially females > 1 y old.

Breast-feeding status alters the effect of vitamin A treatment during acute diarrhea in children

Vitamin A administration in children reduces the incidence of severe diarrhea during the subsequent few months. We therefore examined the effect of treatment with vitamin A during acute diarrhea on the episode duration and severity. In a double-blind controlled field trial, 900 children 1 to 5 y of age with acute diarrhea of < or = 7 d duration were randomly assigned to receive vitamin A (60 mg) or a placebo. Children were followed up at home every alternate day until they recovered from the diarrheal episode. In all study children, those treated with vitamin A had a significantly lower risk of persistent diarrhea [odds ratio (OR) 0.30, 95% confidence interval (CI) 0.07-0.97], but there was no effect on the mean diarrheal duration or the mean stool frequency, in the subgroup of children who were not breast-fed, the mean diarrheal duration [ratio of geometric means (GM) 0.84, 95% CI 0.72-0.97], mean number of stools passed after the intervention (ratio of GM 0.73, 95% CI 0.56-0.95), the proportion of episodes lasting > or = 14 d (P = 0.002) and the percentage of children who passed watery stools on any study day (OR 0.40, 95% CI 0.21-0.77) were significantly lower in those treated with vitamin A. We conclude that administration of vitamin A during acute diarrhea may reduce the severity of the episode and the risk of persistent diarrhea in non-breast-fed children. Similar benefit was not seen in breast-fed children.

Vitamin A therapy for children with respiratory syncytial virus infection: a multicenter trial in the United States

BACKGROUND

High dose vitamin A therapy is effective in reducing morbidity and mortality associated with measles infection. Children with acute respiratory syncytial virus (RSV) infection have low serum vitamin A concentrations.

METHODS

We performed a multicenter, randomized, placebo-controlled trial of high dose vitamin A therapy among 239 children 1 month to 6 years of age to determine whether high dose vitamin A therapy would reduce morbidity associated with RSV infection.

RESULTS

There were no differences between the vitamin A and placebo recipients for most clinical outcomes; however, vitamin A recipients had-longer hospital stays than placebo recipients (5.0 days vs. 4.4 days, P = 0.01) after enrollment. This effect was significant for children who were older than 1 year (who also had received the highest doses of vitamin A), particularly among those at low risk for complications of RSV infection and those enrolled during the second study season. Serum retinol levels at enrollment were inversely correlated with severity of illness.

CONCLUSIONS

We found no evidence of a beneficial effect of vitamin A for the treatment of RSV infection in children in the United States. There may be groups of children for which vitamin A has an adverse effect, resulting in longer hospital stays.

Treatment of respiratory syncytial virus infection with vitamin A: a randomized, placebo-controlled trial in Santiago, Chile

BACKGROUND

Treatment with high dose vitamin A reduces complications and duration of hospitalization for children with measles. In respiratory syncytial virus (RSV) infection, as with measles, low serum vitamin A concentrations correlate with increased severity of illness.

METHODS

To determine whether high dose vitamin A treatment is also effective for treating RSV disease, we conducted a randomized, double blind, placebo-controlled trial among 180 RSV-infected children between 1 month and 6 years of age at three hospitals in Santiago, Chile. Children with nasal washes positive for RSV antigen were given oral vitamin A (50,000 to 200,000 IU of retinyl palmitate, doses according to age; n = 89) or placebo (n = 91) within 2 days of admission.

RESULTS

There was no significant benefit from vitamin A treatment for the overall group in duration of hospitalization, need for supplemental oxygen or time to resolve hypoxemia. For the subgroup of children with significant hypoxemia on admission (room air oxygen saturation level < or = 90%), those given vitamin A had more rapid resolution of tachypnea (P = 0.01) and a shorter duration of hospitalization (5.5 vs. 9.3 days, P = 0.09). No toxicities were seen, including excess vomiting or bulging fontanel.

CONCLUSIONS

If vitamin A has a beneficial effect on the course of RSV disease, it may be seen only in more severely ill children.