Bulging fontanelle after supplementation with 25,000 IU of vitamin A in infancy using immunization contacts

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.

Diagnosis of idiopathic intracranial hypertension - the importance of excluding secondary causes: A systematic review

BACKGROUND

Idiopathic intracranial hypertension is characterized by increased intracranial pressure without any pathological findings on neuroimaging, except for signs of high intracranial pressure. Before diagnosing idiopathic intracranial hypertension secondary causes of increased intracranial pressure should be excluded.

OBJECTIVE

to characterize the phenotype of patients with secondary intracranial hypertension and to identify possible risk factors for secondary intracranial hypertension.

METHODS

We have systematically searched the PubMed database. The publications were analyzed according to the patient phenotype, age, gender, comorbidities, body mass index/weight status, and additional medication. The results are summarized in four categories: medication, infection, hormonal induced intracranial hypertension and miscellaneous groups of diseases related to sIH.

RESULTS

We identified 105 eligible papers which included 272 cases. There were 49.6% pediatric cases. Among the adult group,70.9% were women. A total of 40.4% of all cases were obese or overweight, 27% among adults and 13.4% among pediatric cases. Increased BMI and recent weight gain, anemia, renal diseases and hypertension were the most frequent comorbidities related to sIH.

CONCLUSION

Among sIH patients, 40.4% were obese or overweight; two thirds were women. We recommend that even patients with a typical IIH phenotype should be screened for secondary causes.

Micronutrient Supplementation and Fortification Interventions on Health and Development Outcomes among Children Under-Five in Low- and Middle-Income Countries: A Systematic Review and Meta-Analysis

Micronutrient deficiencies continue to be widespread among children under-five in low- and middle-income countries (LMICs), despite the fact that several effective strategies now exist to prevent them. This kind of malnutrition can have several immediate and long-term consequences, including stunted growth, a higher risk of acquiring infections, and poor development outcomes, all of which may lead to a child not achieving his or her full potential. This review systematically synthesizes the available evidence on the strategies used to prevent micronutrient malnutrition among children under-five in LMICs, including single and multiple micronutrient (MMN) supplementation, lipid-based nutrient supplementation (LNS), targeted and large-scale fortification, and point-of-use-fortification with micronutrient powders (MNPs). We searched relevant databases and grey literature, retrieving 35,924 papers. After application of eligibility criteria, we included 197 unique studies. Of note, we examined the efficacy and effectiveness of interventions. We found that certain outcomes, such as anemia, responded to several intervention types. The risk of anemia was reduced with iron alone, iron-folic acid, MMN supplementation, MNPs, targeted fortification, and large-scale fortification. Stunting and underweight, however, were improved only among children who were provided with LNS, though MMN supplementation also slightly increased length-for-age z-scores. Vitamin A supplementation likely reduced all-cause mortality, while zinc supplementation decreased the incidence of diarrhea. Importantly, many effects of LNS and MNPs held when pooling data from effectiveness studies. Taken together, this evidence further supports the importance of these strategies for reducing the burden of micronutrient malnutrition in children. Population and context should be considered when selecting one or more appropriate interventions for programming.

Safety of Vitamin A Supplementation of Postpartum Women and Young Children

It is now known that the previous World Health Organization (WHO) recommendation for vitamin A supplementation of postpartum women (200,000 IU) is not sufficient and that larger doses are well tolerated. the new recommendation is to give women 400,000 IU during the first eight weeks postpartum, as two 200,000-IU doses separated by at least 24 hours. the most common side effect of large doses of vitamin A in young infants is bulging of the fontanelle. This side effect is rare (0%–8%), spontaneously resolves within 72 hours, and is not associated with significant short- or long-term clinical consequences. A 50,000-IU dose is safe for young infants, but doses greater than 50,000 IU may be harmful, especially for infants under four months of age. the revised WHO recommendation for infants zero to five months old is 150,000 IU as three doses of 50,000 IU with a one-month interval between doses.

Vitamin A supplementation for the prevention of morbidity and mortality in infants one to six months of age

BACKGROUND

Vitamin A deficiency is a significant public health problem in low- and middle-income countries. Vitamin A supplementation provided to infants less than six months of age is one of the strategies to improve the nutrition of infants at high risk of vitamin A deficiency and thus potentially reduce their mortality and morbidity.

OBJECTIVES

To evaluate the effect of synthetic vitamin A supplementation in infants one to six months of age in low- and middle-income countries, irrespective of maternal antenatal or postnatal vitamin A supplementation status, on mortality, morbidity and adverse effects.

SEARCH METHODS

We used the standard search strategy of Cochrane Neonatal to search the Cochrane Central Register of Controlled Trials (CENTRAL 2016, Issue 2), MEDLINE via PubMed (1966 to 5 March 2016), Embase (1980 to 5 March 2016) and CINAHL (1982 to 5 March 2016). We also searched clinical trials databases, conference proceedings and the reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials.

SELECTION CRITERIA

Randomised or quasi-randomised, individually or cluster randomised trials involving synthetic vitamin A supplementation compared to placebo or no intervention provided to infants one to six months of age were eligible.

DATA COLLECTION AND ANALYSIS

Two review authors assessed the studies for eligibility and assessed their risk of bias and collected data on outcomes.

MAIN RESULTS

The review included 12 studies (reported in 22 publications). The included studies assigned 24,846 participants aged one to six months to vitamin A supplementation or control group. There was no effect of vitamin A supplementation for the primary outcome of all-cause mortality based on seven studies that included 21,339 (85%) participants (risk ratio (RR) 1.05, 95% confidence interval (CI) 0.89 to 1.25; I2 = 0%; test for heterogeneity: P = 0.79; quality of evidence: moderate). Also, there was no effect of vitamin A supplementation on mortality or morbidity due to diarrhoea and respiratory tract infection. There was an increased risk of bulging fontanelle within 24 to 72 hours of supplementation in the vitamin A group compared to control (RR 3.10, 95% CI 1.89 to 5.09; I2 = 9%, test for heterogeneity: P = 0.36; quality of evidence: high). There was no reported subsequent increased risk of death, convulsions or irritability in infants who developed bulging fontanelle after vitamin A supplementation, and it resolved in most cases within 72 hours. There was no increased risk of other adverse effects such as vomiting, irritability, diarrhoea, fever and convulsions in the vitamin A supplementation group compared to control. Vitamin A supplementation did not have any statistically significant effect on vitamin A deficiency (RR 0.86, 95% CI 0.70 to 1.06; I2 = 27%; test for heterogeneity: P = 0.25; quality of evidence: moderate).

AUTHORS' CONCLUSIONS

There is no convincing evidence that vitamin A supplementation for infants one to six months of age results in a reduction in infant mortality or morbidity in low- and middle-income countries. There is an increased risk of bulging fontanelle with vitamin A supplementation in this age group; however, there were no reported subsequent complications because of this adverse effect.

Pseudotumor cerebri in a child treated with acitretin: a rare occurrence

Pseudotumor cerebri (PTC) is a rare neurological disorder characterized by increased intracranial pressure in absence of any intra-cranial space-occupying lesion. It is mostly due to impairment of drainage of CSF from arachnoid villi. Clinically pseudotumor cerebri presents with headache, diplopia, nausea, vomiting, papilloedema and if treatment is delayed, may lead to blindness. Females of childbearing age group, endocrinal abnormalities and ingestion of certain drugs have been reported to be associated with pseudotumor cerebri. However, it's occurrence in relation to acitretin ingestion has not been reported on pubmed database. Here we present a case where significant temporal association of acitretin intake with PTC was found in a child who was being treated with this medication for recalcitrant pustular psoriasis. The case is reported for its rarity in occurrence and associated significant morbidity including visual loss if not diagnosed and treated immediately. According to Naranjo ADR Causality scale of adverse drug reaction, the association of PTC due to acitretin in our case was probable.

Vitamin A supplementation for the prevention of morbidity and mortality in infants six months of age or less

BACKGROUND

Vitamin A deficiency is a significant public health problem in low and middle income countries. Vitamin A supplementation (VAS) provided to lactating postpartum mothers or to infants less than six months of age are two possible strategies to improve the nutrition of infants at high risk of vitamin A deficiency and thus potentially reduce their mortality and morbidity.

OBJECTIVES

To evaluate the effect of:1. VAS in postpartum breast feeding mothers in low and middle income countries, irrespective of antenatal VAS status, on mortality, morbidity and adverse effects in their infants up until the age of one year.2. VAS initiated in the first half of infancy (< 6 months of age) in low and middle income countries, irrespective of maternal antenatal or postnatal VAS status, on mortality, morbidity and adverse effects up until the age of one year.

SEARCH STRATEGY

The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library), EMBASE, MEDLINE, clinical trials websites, conference proceedings, donor agencies, 'experts' and researchers (up to October 15, 2010).

SELECTION CRITERIA

Randomized or quasi-randomised, individually or cluster randomised, placebo controlled trials involving synthetic VAS provided to the postpartum mothers or their infants up to the age of six months were eligible.

DATA COLLECTION AND ANALYSIS

Two review authors assessed the studies for their risk of bias and collected data on outcomes.

MAIN RESULTS

Of the 18 included studies, eight provided information on maternal VAS and 15 on infant VAS.For maternal VAS, there was no evidence of a reduced risk of mortality of their babies during infancy (96,203 participants, seven studies, high quality evidence; random-effects model RR 1.00, 95% CI 0.94 to 1.06, P = 0.9; test of heterogeneity I(2) = 0%, P = 0.9) or in the neonatal period (moderate quality evidence); nor of morbidities (very low quality evidence).  For infant VAS, there was no evidence of a reduced risk of mortality during infancy (59,402 participants, nine studies, moderate quality evidence; random-effects model RR 0.97, 0.83 to 1.12, P = 0.65; test of heterogeneity I(2) = 49%, P = 0.05) or in the neonatal period, nor morbidities (low quality evidence), but an increased risk of bulging fontanelle (32,978 participants, 10 studies, low quality evidence; random-effects model RR 1.55, 1.05 to 2.28, P = 0.03; test of heterogeneity I(2) = 68%, P = 0.0009).

AUTHORS' CONCLUSIONS

There is no convincing evidence that either maternal postpartum or infant vitamin A supplementation results in a reduction in infant mortality or morbidity in low and middle income countries.

More than meets the eye? Redefining idiopathic intracranial hypertension

Idiopathic intracranial hypertension (IIH) is a disease of unknown etiology associated with increased intracranial pressure, predominantly affecting obese females of childbearing age. The history of IIH is quite unique, featuring only limited advancements in evidenced-based treatments, but boasting literally countless changes in nomenclature, proposed etiology, and conceptual approach. Despite its elusive pathogenesis, an evolution of our approach to IIH can be traced sequentially through identifiable periods. Contemporary research suggests that we are approaching a new phase in IIH, redefining it as a global neurologic syndrome with more far-reaching effects than previously realized.

Landscape analysis of interactions between nutrition and vaccine responses in children

The world's poorest children are likely to be malnourished when receiving their childhood vaccines. It is uncertain whether this affects vaccine efficacy and whether the coadministration of nutrient supplements with vaccines has beneficial or detrimental effects. More recently, a detrimental interaction between vitamin A (VA) supplementation (VAS) and the killed diphtheria-tetanus-pertussis vaccine given in early childhood has been suggested. This report provides a critical review of the published interactions between nutritional status and/or supplementation and vaccine responses in children. Due to an absence of evidence for most nutrients, this analysis focused on protein-energy, vitamins A and D, and iron and zinc. All vaccines were considered. Both observational studies and clinical trials that led to peer-reviewed publications in English or French were included. These criteria led to a pool of 58 studies for protein-energy malnutrition, 43 for VA, 4 for vitamin D, 10 for iron, and 22 for zinc. Our analysis indicates that malnutrition has surprisingly little or no effect on vaccine responses. Evidence for definitive adjunctive effects of micronutrient supplementation at the time of vaccination is also weak. Overall, the paucity, poor quality, and heterogeneity of data make it difficult to draw firm conclusions. The use of simple endpoints that may not correlate strongly with disease protection adds uncertainty. A detailed examination of the immunological mechanisms involved in potential interactions, employing modern methodologies, is therefore required. This would also help us understand the proposed, but still unproven, negative interactions between VAS and vaccine safety, a resolution of which is urgently required.

Vitamin A supplements are well tolerated with the pentavalent vaccine

The Expanded Programme on Immunisation provides an opportunity to deliver vitamin A supplements to young infants in order to improve their vitamin A status. However, concerns have been raised about the safety of administering high dose vitamin A supplements to infants less than 6 months of age in developing countries. A randomized controlled trial was carried out by the Kintampo Health Research Centre to assess the safety and immunogenicity of administering 15 mg retinol equivalent (RE)1 vitamin A alongside the pentavalent "diphtheria-polio-tetanus-Haemophilus influenzae b-hepatitis B vaccine" at 6, 10 and 14 weeks of age. All mothers received a post-partum supplement of 120 mg RE vitamin A as per national policy. Mothers of infants who had been vaccinated were visited 24 h after vaccination to assess the side effects of the vaccine. They were also interviewed about adverse events which may have occurred in the past 4 weeks since the child was vaccinated. There were significantly fewer reports of illnesses and fever in infants who had been given vitamin A compared to infants in the control group. The pentavalent vaccine was found to be tolerable when administered with vitamin A according to the WHO/EPI schedule for infant immunisation at 6, 10 and 14 weeks. There were few complaints made by the mothers of the children which were not thought to be related to giving vitamin A with the vaccines. There were six deaths in the trial, five in the intervention group and one in the control RR 4.65 (0.55-39.5), p = 0.12. Due to the high point estimate of 4.65, we wish to urge caution in administering high doses of vitamin A to young infants with the pentavalent vaccine at 6, 10 and 14 weeks of age.

Pediatric idiopathic intracranial hypertension

Our understanding of pediatric idiopathic intracranial hypertension has been refined since Dr. Simmons Lessell's review in 1992. The use of rigorous methodologies and standard definitions in recent studies has demonstrated distinct demographic trends. Specifically, the incidence of idiopathic intracranial hypertension seems to be increasing among adolescent children, and among older children its clinical picture is similar to that of adult idiopathic intracranial hypertension (female and obese). Within younger age groups there are more boys and nonobese children who may develop idiopathic intracranial hypertension. The pathogenesis of the disease has yet to be elucidated. Idiopathic intracranial hypertension among young children has been associated with several new etiologies, including recombinant growth hormone and all-trans-retinoic acid. More modern neuroimaging techniques such as MRI and MRI-venograms are being used to exclude intracranial processes. Although most cases of pediatric idiopathic intracranial hypertension improve with medical treatment, those who have had visual progression despite medical treatment have undergone optic nerve sheath fenestration and lumboperitoneal shunting. Because idiopathic intracranial hypertension in young children appears to be a different disorder than in adolescents and adults, separate diagnostic criteria for younger children are warranted. We propose new criteria for pediatric idiopathic intracranial hypertension in which children should have signs or symptoms consistent with elevated intracranial pressure, be prepubertal, have normal sensorium, can have reversible cranial nerve palsies, and have an opening cerebrospinal fluid pressure greater than 180 mm H(2)O if less than age 8 and papilledema is present, but greater than 250 mm H(2)0 if age 8 or above or less than 8 without papilledema.

One-time graded doses of vitamin A to weanling piglets enhance hepatic retinol but do not always prevent vitamin A deficiency

BACKGROUND

Vitamin A supplements are administered to infants in developing countries at immunization contacts; doses of 50000 IU vitamin A are recommended. Doses of 100000 IU are given to children aged 0.5-1 y. The efficacy of these doses has not been adequately determined.

OBJECTIVE

We aimed to quantify liver vitamin A after the administration of vitamin A doses to piglets. Piglets are a good model for infants because of their similar size, gastrointestinal anatomy, and vitamin A requirements.

DESIGN

Castrated male piglets born to sows fed a vitamin A-depleted diet throughout 1 (parity A) or 3 (parity B) pregnancy and lactation cycles were randomly assigned to receive 1 of 4 oral vitamin A doses (ie, 0, 25000, 50000, or 100000 IU) at weaning (days 9-14). A vitamin A-depleted diet was fed until the piglets were killed on day 10. Serum retinol was measured on days 1, 2, 4, 7, and 10. The modified relative dose response was measured before supplementation and at the time of killing, and liver vitamin A concentration was measured.

RESULTS

In both parities, 25000 IU did not result in a mean liver retinol reserve > 0.07 micromol/g liver (the deficiency cutoff). The 50000-IU dose increased mean reserves above 0.07 micromol/g only in parity A. Liver vitamin A reserves with the 100000-IU treatment were only 5% above those with the 50000-IU treatment. The modified relative dose-response test reflected differences in liver vitamin A stores in parity B, and the 0-IU group differed significantly from the 100000-IU group (P = 0.011).

CONCLUSION

This piglet model suggests that, for supplementation to infants <6 mo old, a 50000-IU dose is likely to be more efficacious in mitigating deficiency than is a 25000-IU dose.

No adverse events after simultaneous administration of 50 000 IU vitamin A and Bacille Calmette-Guerin vaccination to normal-birth-weight newborns in Guinea-Bissau

OBJECTIVE

To determine whether the combined intervention of 50 000 IU vitamin A administered together with Bacille Calmette-Guerin (BCG) vaccination at birth was associated with adverse events, in particular bulging fontanels and adverse reactions to BCG.

SUBJECTS/METHODS

From an ongoing trial, 2145 infants randomized to 50 000 IU vitamin A or placebo with BCG vaccination were recruited. Adverse events were monitored in two different ways: (A) daily clinical examinations by a medical doctor during the first 3 days post supplementation; (B) weekly interviews by a trained assistant during the first month post supplementation.

RESULTS

In part A, 1271 infants were enrolled, in part B 2078. Vitamin A supplementation (VAS) was associated with a relative risk (RR) of bulging fontanels of 1.16 (95% confidence interval (CI)=0.82-1.65). The rate of health care contacts and various symptoms during the first month were comparable between the groups. VAS was associated with larger peak local reactions to BCG vaccination in boys, but not in girls (P-value for test of interaction between VAS and sex=0.02).

CONCLUSION

50 000 IU vitamin A with BCG was not associated with adverse events. The observed sex-differential effect of VAS on local reaction to BCG is in line with other observations of sex-differential effects of VAS.

Transient bulging fontanelle after vaccination: case report and review of the vaccine adverse event reporting system

OBJECTIVE

To describe the features of transient bulging fontanelle (TBF) after vaccination.

STUDY DESIGN

We searched the Vaccine Adverse Event Reporting System database for reports describing bulging fontanelle. We defined a definite TBF case as a patient with a bulging fontanelle, normal neuroimaging and cerebrospinal fluid analysis, and absence of a depressed level of consciousness, focal neurologic findings, or identified cause. Follow-up had to reveal normal development. Probable cases lacked either lumbar puncture or neuroimaging or both but met all other criteria.

RESULTS

We identified 18 patients with definite or probable TBF. The median age at presentation was 4.5 months, interval from vaccination to symptom onset was 18 hours, and time to resolution was 3 days. Fifteen children were febrile.

CONCLUSIONS

We cannot conclude that vaccines cause TBF. Further controlled studies are necessary. Even if further research verifies TBF as a rare side effect, immunization benefits would still vastly outweigh this hypothetical risk. However, confirmation of a vaccine association could modify the management of infants who develop TBF after immunizations.

Medication-induced intracranial hypertension in dermatology

Pseudotumor cerebri (PTC) is a syndrome of intracranial hypertension that is idiopathic or from an identified secondary cause. It is characterized by headaches and visual manifestations. The hallmark of PTC is papilledema and the feared consequence is visual loss that may be severe and permanent. The idiopathic form generally occurs in obese women of childbearing age. Various medications may produce PTC in patients at any age, including children. Several medications used in dermatology, particularly those used in the treatment of acne vulgaris, are associated with PTC. There is a strong association with tetracycline usage. Minocycline and doxycycline have also been linked to PTC, although there are relatively few reported cases. PTC has also been described with retinoids, including vitamin A (retinol) and isotretinoin. Although corticosteroids are often used to lower intracranial pressure acutely, corticosteroid withdrawal after long-term administration may induce increased intracranial pressure. A high index of suspicion, early diagnosis and treatment generally yield a good prognosis.

Water-miscible, emulsified, and solid forms of retinol supplements are more toxic than oil-based preparations

BACKGROUND

It is well established that an excessive intake of retinol (vitamin A) is toxic; however, it has been > 25 y since the last extensive treatise of case reports on this subject.

OBJECTIVE

The objectives were to identify and evaluate all individual cases of retinol toxicity published in the scientific literature that assessed the thresholds and symptoms induced by high intakes of retinol and to compare the toxicity of different physical forms of retinol preparations.

DESIGN

We performed a meta-analysis of case reports on toxicity claimed to be induced by intakes of excessive amounts of dietary retinol (ie, retinol and retinyl esters in foods or supplements). Using free text and MESH (medical subheading) strategies in PubMed, we identified 248 articles in the scientific literature. From these initial articles we identified other relevant citations. The final database consisted of 259 cases in which individual data on dose, sex, age, time of exposure, and symptoms are reported.

RESULTS

Chronic hypervitaminosis A is induced after daily doses of 2 mg retinol/kg in oil-based preparations for many months or years. In contrast, doses as low as 0.2 mg retinol. kg(-1). d(-1) in water-miscible, emulsified, and solid preparations for only a few weeks caused chronic hypervitaminosis A. Thus, water-miscible, emulsified, and solid preparations of retinol are approximately 10 times as toxic as are oil-based retinol preparations. The safe upper single dose of retinol in oil or liver seems to be approximately 4-6 mg/kg body wt. These thresholds do not vary considerably with age.

CONCLUSIONS

The results of the present study indicate that the physical form of retinol supplements is a major determinant of toxicity. The use of water-miscible, emulsified, and solid preparations of retinol should therefore be carefully considered before being used in supplements and fortifications.

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.

Micronutrients as adjunct therapy of acute illness in children: impact on the episode outcome and policy implications of current findings

Role of micronutrients namely vitamin A, zinc and folate, as adjunct therapy of illness episodes in children in developing countries have been discussed in the light of health policy. Apart from a selective review, attempts have been made to statistically combine results of several studies to address policy issues. In children, vitamin A supplementation during illness has (a) a profound effect in reducing mortality in measles, (b) possibly a significant effect in reducing persistent diarrhea episodes in children with acute diarrhea, and (c) no benefit in pneumonia. Use of large dose vitamin A is recommended during measles episodes but not in non-measles pneumonia. Its use in acute diarrhea is debatable but recommended in persistent diarrhea and in severe malnutrition as a component of a micronutrient mixture. Large dose vitamin A supplementation should be used with caution in young infants as there are unresolved concerns about its safety particularly, bulging fontanelle observed in infants when co-administered at immunization. In children, zinc supplementation during illness, (a) had a marked effect in reducing prolonged episodes and a modest effect on episode duration in acute diarrhea, (b) resulted in reduced rate of treatment failure and death in persistent diarrhea, (c) had no effect in measles and non-measles pneumonia, and (d) probably had a detrimental effect of increasing death rate when a large dose was used in severely malnourished children. The desirability of routine zinc supplementation therapy of undernourished children with acute diarrhea should be assessed further. Concerning policy, zinc supplementation as a component of a micronutrient mixture is recommended in the rehabilitation of severely malnourished children and in persistent diarrhea. However, recommendation for its routine use in all cases of acute diarrhea in children needs additional studies on effectiveness, cost, operations and safety. In two randomized controlled trials folate has been evaluated in acute and persistent diarrhea and found to have no beneficial effect. Folate is not recommended as adjunct therapy of diarrhea. Role of folate in preventing severe disease and/or death deserves further evaluation.

Vitamin A in pregnancy: requirements and safety limits

Most of the functions of vitamin A are mediated through the binding of retinoic acid to specific nuclear receptors that regulate genomic expression. Recent experimental work in transgenic mice showed clearly that normal embryonic development depends on the correct spatial and temporal expression of the receptors in the differentiating cells and on the binding of specific forms of retinoic acid. This implies that the parent compound, vitamin A, is available in adequate forms and quantities. Excessive dietary intake of vitamin A has been associated with teratogenicity in humans in <20 reported cases over 30 y. However, caution must be exercised to avoid unnecessary supplementation of women of childbearing age. Hypovitaminosis A affects millions of women and children worldwide. The main consequence of a poor vitamin A supply during pregnancy is a low vitamin A status at birth and in the next few months. Vitamin A deficiency is strongly associated with depressed immune function and higher morbidity and mortality due to infectious diseases such as diarrhea, measles, and respiratory infections. Vitamin A deficiency is often associated with an increased mother-to-child transmission of HIV-1. The initiation of vitamin A supplementation should be carefully examined in each case according to the risk-to-benefit ratio. The final decision should take into account the estimated vitamin A status of the woman, the availability of vitamin A-rich foods in her diet, and whether supplementation can be supervised.

Maternal vitamin A or beta-carotene supplementation in lactating bangladeshi women benefits mothers and infants but does not prevent subclinical deficiency

The effects of maternal postpartum vitamin A or beta-carotene supplementation on maternal and infant serum retinol concentrations, modified relative dose-response (MRDR) ratios and breast milk vitamin A concentrations were assessed during a community-based trial in Matlab, Bangladesh. At 1-3 wk postpartum, women were randomly assigned to receive either (1) a single dose of 200,000 international units [60,000 retinol equivalents (RE)] vitamin A followed by daily placebos (n = 74), (2) daily doses of beta-carotene [7.8 mg (1300 RE)] (n = 73) or (3) daily placebos (n = 73) until 9 mo postpartum. Compared to placebos, vitamin A supplementation resulted in lower maternal MRDR ratios (i.e., increased liver stores) and higher milk vitamin A concentrations at 3 mo, but these improvements were not sustained. The beta-carotene supplementation acted more slowly, resulting in milk vitamin A concentrations higher than the placebo group only at 9 mo. Irrespective of treatment group, over 50% of women produced milk with low vitamin A concentrations (</=1.05 micromol/L or </=0.28 micromol/g fat) throughout the study. Overall, mean maternal serum retinol concentrations were not affected by supplementation. Compared to the placebo group, the mean MRDR ratio of 6-mo-old infants was higher in the vitamin A group. Infants (33%) had serum retinol concentrations <0.70 micromol/L and 88% had MRDR ratios >/=0. 06. We conclude that while both interventions were beneficial, neither was sufficient to correct the underlying subclinical vitamin A deficiency in these women nor to bring their infants into adequate vitamin A status.

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.