A randomized controlled study of the impact of dietary zinc supplementation in the management of children with protein-energy malnutrition in Lesotho. I: Mortality and morbidity

Micronutrient status in children aged 6-59 months with severe wasting and/or nutritional edema: implications for nutritional rehabilitation formulations

Undernutrition remains a global struggle and is associated with almost 45% of deaths in children younger than 5 years. Despite advances in management of severe wasting (though less so for nutritional edema), full and sustained recovery remains elusive. Children with severe wasting and/or nutritional edema (also commonly referred to as severe acute malnutrition and part of the umbrella term "severe malnutrition") continue to have a high mortality rate. This suggests a likely multifactorial etiology that may include micronutrient deficiency. Micronutrients are currently provided in therapeutic foods at levels based on expert opinion, with few supportive studies of high quality having been conducted. This narrative review looks at the knowledge base on micronutrient deficiencies in children aged 6-59 months who have severe wasting and/or nutritional edema, in addition to highlighting areas where further research is warranted (See "Future Directions" section).

Effect of zinc supplementation on mortality in under 5-year children: a systematic review and meta-analysis of randomized clinical trials

BACKGROUND

Several clinical trials evaluated the effect of zinc supplementation on mortality in children, but the results were inconsistent. We aimed to conduct a systematic review and meta-analysis on the impact of zinc supplementation on mortality in under 5-year children.

METHODS

A comprehensive search was conducted using the electronic (PubMed, Scopus, Web of Science) databases, and Google Scholar, up to June 2020. Randomized clinical trials (RCTs) that reported the effect of zinc supplementation on death incidence in under 5-year children were included in the analysis. Screening was performed based on title/abstract and full-text. A random effects model was applied to calculate the summary relative risk (SRR). Risk of Bias 2.0 tool was used to rate the quality of trials. The body of evidence was assessed by the GRADE approach.

RESULTS

Combining 30 RRs from 28 RCTs including 237,068 participants revealed that zinc supplementation has significantly reduced the risk of all-causes mortality by 16% in children (SRR: 0.84, 95% CI: 0.74, 0.96). A follow-up duration of less than 1 year after supplementation resulted in 54% reduced risk of mortality (0.46; 0.33, 0.63) with no heterogeneity between investigations. Subgroup analysis by zinc dosage showed that assigning ≥ 10 mg/d zinc to under five children and duration of less than 11 months of intervention decreased the risk of all-cause mortality by 44% (0.56; 0.42, 0.75) and 48% (0.52; 0.38, 0.72), respectively. In low birth weight (LBW) infants, zinc supplementation was reduced all-cause mortality by 52% (0.48; 0.23, 1.00). Zinc supplementation significantly reduced the risk of death from pneumonia (0.70: 0.64, 0.98) and infection (0.54; 0.39, 0.76), also changed the risk of mortality from diarrhea by 15% (0.85; 0.70, 1.03) and sepsis by 57% (0.43; 0.18, 1.02).

CONCLUSION

This meta-analysis on RCTs revealed that zinc supplementation in under 5-year children has significantly reduced the risk of all-cause mortality. Notable decreases were found in trials with a dose of 10 mg/d or more zinc supplementation, a maximum of 11 months of supplementation, a follow-up less than one year and especially in LBW infants.

Antimicrobial and micronutrient interventions for the management of infants under 6 months of age identified with severe malnutrition: a literature review

BACKGROUND

Infants under 6 months (U6M) contribute a significant proportion of the burden and mortality of severe malnutrition globally. Evidence of underlying aetiology in this population is sparse, but it is known that the group includes ex-preterm and low birthweight (LBW) infants. They represent a unique population given their dependence on breastmilk or a safe, secure alternative. Nutrition agencies and health providers struggle to make programming decisions on which interventions should be provided to this group based upon the 2013 WHO Guidelines for the 'Management of Severe Acute Malnutrition in Infants and Young Children' since there are no published interventional trial data focussed on this population. Interim guidance for this group might be informed by evidence of safety and efficacy in adjacent population groups.

METHODOLOGY

A narrative literature review was performed of systematic reviews, meta-analyses and randomised controlled trials of antimicrobial and micronutrient interventions (antibiotics, deworming, vitamin A, vitamin D, iron, zinc, folic acid and oral rehydration solution (ORS) for malnutrition) across the population groups of low birthweight/preterm infants, infants under 6 months, infants and children over 6 months with acute malnutrition or through supplementation to breastfeeding mothers. Outcomes of interest were safety and efficacy, in terms of mortality and morbidity.

RESULTS

Ninety-four articles were identified for inclusion within this review. None of these studied interventions exclusively in severely malnourished infants U6M. 64% reported on the safety of studied interventions. Significant heterogeneity was identified in definitions of study populations, interventions provided, and outcomes studied. The evidence for efficacy and safety across population groups is reviewed and presented for the interventions listed.

CONCLUSIONS

The direct evidence base for medical interventions for severely malnourished infants U6M is sparse. Our review identifies a specific need for accurate micronutrient profiling and interventional studies of micronutrients and oral fluid management of diarrhoea amongst infants U6M meeting anthropometric criteria for severe malnutrition. Indirect evidence presented in this review may help shape interim policy and programming decisions as well as the future research agenda for the management of infants U6M identified as malnourished.

Oral zinc for treating diarrhoea in children

BACKGROUND

In developing countries, diarrhoea causes around 500,000 child deaths annually. Zinc supplementation during acute diarrhoea is currently recommended by the World Health Organization (WHO) and the United Nations Children's Fund (UNICEF).

OBJECTIVES

To evaluate oral zinc supplementation for treating children with acute or persistent diarrhoea.

SEARCH METHODS

We searched the Cochrane Infectious Diseases Group Specialized Register, CENTRAL (the Cochrane Library 2016, Issue 5), MEDLINE, Embase, LILACS, CINAHL, mRCT, and reference lists up to 30 September 2016. We also contacted researchers.

SELECTION CRITERIA

Randomized controlled trials (RCTs) that compared oral zinc supplementation with placebo in children aged one month to five years with acute or persistent diarrhoea, including dysentery.

DATA COLLECTION AND ANALYSIS

Both review authors assessed trial eligibility and risk of bias, extracted and analysed data, and drafted the review. The primary outcomes were diarrhoea duration and severity. We summarized dichotomous outcomes using risk ratios (RR) and continuous outcomes using mean differences (MD) with 95% confidence intervals (CI). Where appropriate, we combined data in meta-analyses (using either a fixed-effect or random-effects model) and assessed heterogeneity.We assessed the certainty of the evidence using the GRADE approach.

MAIN RESULTS

Thirty-three trials that included 10,841 children met our inclusion criteria. Most included trials were conducted in Asian countries that were at high risk of zinc deficiency. Acute diarrhoeaThere is currently not enough evidence from well-conducted RCTs to be able to say whether zinc supplementation during acute diarrhoea reduces death or number of children hospitalized (very low certainty evidence).In children older than six months of age, zinc supplementation may shorten the average duration of diarrhoea by around half a day (MD -11.46 hours, 95% CI -19.72 to -3.19; 2581 children, 9 trials, low certainty evidence), and probably reduces the number of children whose diarrhoea persists until day seven (RR 0.73, 95% CI 0.61 to 0.88; 3865 children, 6 trials, moderate certainty evidence). In children with signs of malnutrition the effect appears greater, reducing the duration of diarrhoea by around a day (MD -26.39 hours, 95% CI -36.54 to -16.23; 419 children, 5 trials, high certainty evidence).Conversely, in children younger than six months of age, the available evidence suggests zinc supplementation may have no effect on the mean duration of diarrhoea (MD 5.23 hours, 95% CI -4.00 to 14.45; 1334 children, 2 trials, moderate certainty evidence), or the number of children who still have diarrhoea on day seven (RR 1.24, 95% CI 0.99 to 1.54; 1074 children, 1 trial, moderate certainty evidence).None of the included trials reported serious adverse events. However, zinc supplementation increased the risk of vomiting in both age groups (children greater than six months of age: RR 1.57, 95% CI 1.32 to 1.86; 2605 children, 6 trials, moderate certainty evidence; children less than six months of age: RR 1.54, 95% CI 1.05 to 2.24; 1334 children, 2 trials, moderate certainty evidence). Persistent diarrhoeaIn children with persistent diarrhoea, zinc supplementation probably shortens the average duration of diarrhoea by around 16 hours (MD -15.84 hours, 95% CI -25.43 to -6.24; 529 children, 5 trials, moderate certainty evidence).

AUTHORS' CONCLUSIONS

In areas where the prevalence of zinc deficiency or the prevalence of malnutrition is high, zinc may be of benefit in children aged six months or more. The current evidence does not support the use of zinc supplementation in children less six months of age, in well-nourished children, and in settings where children are at low risk of zinc deficiency.

Protein energy-malnutrition: does the in vitro zinc sulfate supplementation improve chromosomal damage repair?

Protein-energy malnutrition (PEM) is originated by a cellular imbalance between nutrient/energy supply and body's demand. Induction of genetic damage by PEM was reported. The purpose of this study was to determine the genetic effect of the in vitro zinc sulfate (ZnSO4) supplementation of cultured peripheral blood lymphocytes from children with PEM. Twenty-four samples from 12 children were analyzed. Anthropometric and biochemical diagnosis was made. For the anthropometric assessment, height-for-age index, weight-for-age index, and weight-for-height index were calculated (WHO, 2005). Micronutrient status was evaluated. A survey for assessed previous exposure to potentially genotoxic agents was applied. Results were statistically evaluated using paired sample t test and χ (2) test. Each sample was fractionated and cultured in two separate flasks to performed two treatments. One was added with 180 μg/dl of ZnSO4 (PEMs/ZnSO4) and the other remains non-supplemented (PEMs). Cytotoxic effects and chromosomal damage were assessed using the cytokinesis-block micronucleus assay (CBMN). All participants have at least one type of malnutrition and none have anemia, nor iron, folate, vitamin A, and zinc deficiency. All PEMs/ZnSO4 samples have a significant reduction in the micronucleus (MNi) frequency compared with PEMs (t = 6.25685; p < 0.001). Nuclear division index (NDI) increase in PEMs/ZnSO4 (t = -17.4226; p < 0.001). Nucleoplasmic bridge (NPBs) frequency was four times smaller in PEMs/ZnSO4 (χ (2) = 40.82; p < 0.001). No nuclear buds (NBuds) were observed. Cytotoxic effects and chromosomal damage observed in children suffering from PEM can be repaired in vitro with zinc sulfate supplementation.

Zinc supplements for preventing otitis media

BACKGROUND

Otitis media is inflammation of the middle ear and is usually caused by infection. It affects people of all ages but is particularly common in young children. Around 164 million people worldwide have long-term hearing loss caused by this condition, 90% of them in low-income countries. As zinc supplements prevent pneumonia in disadvantaged children, we wanted to investigate whether zinc supplements could also prevent otitis media.

OBJECTIVES

To evaluate whether zinc supplements prevent otitis media in adults and children of different ages.

SEARCH METHODS

We searched CENTRAL (2014, Issue 1), MEDLINE (1950 to February week 4, 2014) and EMBASE (1974 to March 2014).

SELECTION CRITERIA

Randomised, placebo-controlled trials of zinc supplements given at least once a week for at least a month for preventing otitis media.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the eligibility and methodological quality of the included trials and extracted and analysed data. We summarised results using risk ratios (RRs) or rate ratios for dichotomous data and mean differences (MDs) for continuous data. We combined trial results where appropriate.

MAIN RESULTS

No new trials were identified for inclusion in this update. We identified 12 trials for inclusion, 10 of which contributed outcomes data. There were a total of 6820 participants. In trials of healthy children living in low-income communities, two trials did not demonstrate a significant difference between the zinc-supplemented and placebo groups in the numbers of participants experiencing an episode of definite otitis media during follow-up (3191 participants); another trial showed a significantly lower incidence rate of otitis media in the zinc group (rate ratio 0.69, 95% confidence interval (CI) 0.61 to 0.79, n = 1621). A small trial of 39 infants undergoing treatment for severe malnutrition suggested a benefit of zinc for the mean number of episodes of otitis media (mean difference (MD) -1.12 episodes, 95% CI -2.21 to -0.03). Zinc supplements did not seem to cause any serious adverse events but a small minority of children were reported to have vomited shortly after ingestion of the supplements. The trial evidence included is generally of good quality, with a low risk of bias.

AUTHORS' CONCLUSIONS

Evidence on whether zinc supplementation can reduce the incidence of otitis media in healthy children under the age of five years living in low- and middle-income countries is mixed. There is some evidence of benefit in children being treated for marasmus (severe malnutrition), but this is based on one small trial and should therefore be treated with caution.

Zinc monotherapy increases serum brain-derived neurotrophic factor (BDNF) levels and decreases depressive symptoms in overweight or obese subjects: a double-blind, randomized, placebo-controlled trial

OBJECTIVE

Previous studies have shown a positive effect of zinc as an adjunctive therapy on reducing depressive symptoms. However, to our knowledge, no study has examined the effect of zinc monotherapy on mood. The aim of the present study was to determine the effects of zinc monotherapy on depressive symptoms and serum brain-derived neurotrophic factor (BDNF) levels in overweight or obese subjects.

METHODS

Fifty overweight or obese subjects were randomly assigned into two groups and received either 30 mg zinc or placebo daily for 12 weeks. At baseline and post-intervention, depression severity was assessed using Beck depression inventory II (BDI II), and serum BDNF and zinc levels were determined by enzyme-linked immunosorbent assay and atomic absorption spectrophotometry, respectively.

RESULTS

The trial was completed with 46 subjects. After a 12-week supplementation, serum zinc and BDNF levels increased significantly in the zinc-supplemented group compared with the placebo group. BDI scores declined in both the groups at the end of the study, but reduction in the zinc-supplemented group was significantly higher than the placebo group. More analysis revealed that following supplementation, BDI scores decreased in subgroup of subjects with depressive symptoms (BDI ≥ 10) (n = 30), but did not change in the subgroup of non-depressed subjects (BDI < 10) (n = 16). Moreover, a significant inverse correlation was observed between serum BDNF levels and depression severity in all participants. Interestingly, a significant positive correlation was found between serum BDNF and zinc levels at baseline.

CONCLUSION

Zinc monotherapy improves mood in overweight or obese subjects most likely through increasing BDNF levels.

Effect of zinc intake on serum/plasma zinc status in infants: a meta-analysis

A systematic review and meta-analysis of available randomised controlled trials (RCTs) was conducted to evaluate the effect of zinc (Zn) intake on serum/plasma Zn status in infants. Out of 5500 studies identified through electronic searches and reference lists, 13 RCTs were selected after applying the exclusion/inclusion criteria. The influence of Zn intake on serum/plasma Zn concentration was considered in the overall meta-analysis. Other variables were also taken into account as possible effect modifiers: doses of Zn intake, intervention duration, nutritional status and risk of bias. The pooled β of status was 0.09 [confidence interval (CI) 0.05 to 0.12]. However, a substantial heterogeneity was present in the analyses (I(2) = 98%; P = 0.00001). When we performed a meta-regression, the effect of Zn intake on serum/plasma Zn status changed depending on the duration of the intervention, the dose of supplementation and the nutritional situation (P ANCOVA = 0.054; <0.001 and <0.007, respectively). After stratifying the sample according to the effect modifiers, the results by duration of intervention showed a positive effect when Zn intake was provided during medium and long periods of time (4-20 weeks and >20 weeks). A positive effect was also seen when doses ranged from 8.1 to 12 mg day(-1). In all cases, the pooled β showed high evidence of heterogeneity. Zn supplementation increases serum/plasma Zn status in infants, although high evidence of heterogeneity was found. Further standardised research is urgently needed to reach evidence-based conclusions to clarify the role of Zn supplementation upon infant serum/plasma Zn status, particularly in Europe.

Oral zinc for treating diarrhoea in children

BACKGROUND

In developing countries, diarrhoea causes around two million child deaths annually. Zinc supplementation during acute diarrhoea is currently recommended by the World Health Organization and UNICEF.

OBJECTIVES

To evaluate oral zinc supplementation for treating children with acute or persistent diarrhoea.

SEARCH METHODS

In February 2012, we searched the Cochrane Infectious Diseases Group Specialized Register, CENTRAL (The Cochrane Library 2011, Issue 11), MEDLINE, EMBASE, LILACS, CINAHL, mRCT, and reference lists. We also contacted researchers.

SELECTION CRITERIA

Randomized controlled trials comparing oral zinc supplementation with placebo in children aged one month to five years with acute or persistent diarrhoea, including dysentery.

DATA COLLECTION AND ANALYSIS

Both authors assessed trial eligibility and risk of bias, extracted and analysed data, and drafted the review. Diarrhoea duration and severity were the primary outcomes. We summarized dichotomous outcomes using risk ratios (RR) and continuous outcomes using mean differences (MD) with 95% confidence intervals (CI). Where appropriate, we combined data in meta-analyses (using the fixed- or random-effects model) and assessed heterogeneity.The quality of evidence has been assessed using the GRADE methods

MAIN RESULTS

Twenty-four trials, enrolling 9128 children, met our inclusion criteria. The majority of the data is from Asia, from countries at high risk of zinc deficiency, and may not be applicable elsewhere. Acute diarrhoea. There is currently not enough evidence from well conducted randomized controlled trials to be able to say whether zinc supplementation during acute diarrhoea reduces death or hospitalization (very low quality evidence).In children aged greater than six months with acute diarrhoea, zinc supplementation may shorten the duration of diarrhoea by around 10 hours (MD -10.44 hours, 95% CI -21.13 to 0.25; 2175 children, six trials, low quality evidence), and probably reduces the number of children whose diarrhoea persists until day seven (RR 0.73, 95% CI 0.61 to 0.88; 3865 children, six trials, moderate quality evidence). In children with signs of moderate malnutrition the effect appears greater, reducing the duration of diarrhoea by around 27 hours (MD -26.98 hours, 95% CI -14.62 to -39.34; 336 children, three trials, high quality evidence).Conversely, In children aged less than six months, the available evidence suggests zinc supplementation may have no effect on mean diarrhoea duration (MD 5.23 hours, 95% CI -4.00 to 14.45; 1334 children, two trials, low quality evidence), and may even increase the proportion of children whose diarrhoea persists until day seven (RR 1.24, 95% CI 0.99 to 1.54; 1074 children, one trial, moderate quality evidence).No trials reported serious adverse events, but zinc supplementation during acute diarrhoea causes vomiting in both age groups (RR 1.59, 95% 1.27 to 1.99; 5189 children, 10 trials, high quality evidence). Persistent diarrhoea. In children with persistent diarrhoea, zinc supplementation probably shortens the duration of diarrhoea by around 16 hours (MD -15.84 hours, 95% CI -25.43 to -6.24; 529 children, five trials, moderate quality evidence).

AUTHORS' CONCLUSIONS

In areas where the prevalence of zinc deficiency or the prevalence of moderate malnutrition is high, zinc may be of benefit in children aged six months or more.The current evidence does not support the use of zinc supplementation in children below six months of age.

High burden of protein-energy malnutrition in Nigeria: beyond the health care setting

There is still a high burden of protein–energy malnutrition in Nigeria. The severe forms of the disease are usually associated with high level of mortality even in the tertiary health facilities. To review the cost-effective health promotional strategies at community levels that could aid prevention, early detection, and prompt treatment of protein–energy malnutrition. The strategy used for locating articles used for this review was to search databases like Google, Google scholar, relevant electronic journals from the universities’ libraries, including PubMed and Scirus, Medline, Cochrane library and WHO's Hinari. We believe that strategies beyond the health care setting have potential of significantly reducing the morbidity and mortality associated with protein–energy malnutrition in Nigeria.

Oral zinc for treating diarrhoea in children

BACKGROUND

In developing countries, diarrhoea causes around two million child deaths annually. Zinc supplementation during acute diarrhoea is currently recommended by the World Health Organization and UNICEF.

OBJECTIVES

To evaluate oral zinc supplementation for treating children with acute or persistent diarrhoea.

SEARCH METHODS

In February 2012, we searched the Cochrane Infectious Diseases Group Specialized Register, CENTRAL (The Cochrane Library 2011, Issue 11), MEDLINE, EMBASE, LILACS, CINAHL, mRCT, and reference lists. We also contacted researchers.

SELECTION CRITERIA

Randomized controlled trials comparing oral zinc supplementation with placebo in children aged one month to five years with acute or persistent diarrhoea, including dysentery.

DATA COLLECTION AND ANALYSIS

Both authors assessed trial eligibility and risk of bias, extracted and analysed data, and drafted the review. Diarrhoea duration and severity were the primary outcomes. We summarized dichotomous outcomes using risk ratios (RR) and continuous outcomes using mean differences (MD) with 95% confidence intervals (CI). Where appropriate, we combined data in meta-analyses (using the fixed- or random-effects model) and assessed heterogeneity.The quality of evidence has been assessed using the GRADE methods

MAIN RESULTS

Twenty-four trials, enrolling 9128 children, met our inclusion criteria. The majority of the data is from Asia, from countries at high risk of zinc deficiency, and may not be applicable elsewhere.Acute diarrhoeaThere is currently not enough evidence from well conducted randomized controlled trials to be able to say whether zinc supplementation during acute diarrhoea reduces death or hospitalization (very low quality evidence).In children aged greater than six months with acute diarrhoea, zinc supplementation may shorten the duration of diarrhoea by around 10 hours (MD -10.44 hours, 95% CI -21.13 to 0.25; 2091 children, five trials, low quality evidence), and probably reduces the number of children whose diarrhoea persists until day seven (RR 0.73, 95% CI 0.61 to 0.88; 3865 children, six trials, moderate quality evidence). In children with signs of moderate malnutrition the effect appears greater, reducing the duration of diarrhoea by around 27 hours (MD -26.98 hours, 95% CI -14.62 to -39.34; 336 children, three trials, high quality evidence).Conversely, In children aged less than six months, the available evidence suggests zinc supplementation may have no effect on mean diarrhoea duration (MD 5.23 hours, 95% CI -4.00 to 14.45; 1334 children, two trials, low quality evidence), and may even increase the proportion of children whose diarrhoea persists until day seven (RR 1.24, 95% CI 0.99 to 1.54; 1074 children, one trial, moderate quality evidence).No trials reported serious adverse events, but zinc supplementation during acute diarrhoea causes vomiting in both age groups (RR 1.59, 95% 1.27 to 1.99; 5189 children, 10 trials, high quality evidence).Persistent diarrhoeaIn children with persistent diarrhoea, zinc supplementation probably shortens the duration of diarrhoea by around 16 hours (MD -15.84 hours, 95% CI -25.43 to -6.24; 529 children, five trials, moderate quality evidence).

AUTHORS' CONCLUSIONS

In areas where the prevalence of zinc deficiency or the prevalence of moderate malnutrition is high, zinc may be of benefit in children aged six months or more.The current evidence does not support the use of zinc supplementation in children below six months of age.

Zinc supplements for preventing otitis media

BACKGROUND

Otitis media (OM) is inflammation of the middle ear and is usually caused by infection. It affects people of all ages but is particularly common in young children. Around 164 million people worldwide have long-term hearing loss caused by this condition, 90% of them in low-income countries. As zinc supplements prevent pneumonia in disadvantaged children, we wanted to investigate whether zinc supplements could also prevent OM.

OBJECTIVES

To evaluate whether zinc supplements prevent OM in adults and children of different ages.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL 2012, Issue 1) which includes the Cochrane Acute Respiratory Infections Groups' Specialised Register, MEDLINE (1950 to February week 1, 2012) and EMBASE (1974 to February 2012).

SELECTION CRITERIA

Randomised, placebo-controlled trials of zinc supplements given at least once a week for at least a month for preventing OM.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the eligibility and methodological quality of the included trials and extracted and analysed data. We summarised results using risk ratios (RRs) or rate ratios for dichotomous data and mean differences (MDs) for continuous data. We combined trial results where appropriate.

MAIN RESULTS

We identified 12 trials for inclusion, 10 of which contributed outcomes data. There was a total of 6820 participants. In trials of healthy children living in low-income communities, two trials did not demonstrate a significant difference between the zinc supplemented and placebo groups in the numbers of participants experiencing an episode of definite OM during follow-up (3191 participants); another trial showed a significantly lower incidence rate of OM in the zinc group (rate ratio 0.69, 95% confidence interval (CI) 0.61 to 0.79, n = 1621). A small trial of 39 infants undergoing treatment for severe malnutrition suggested a benefit of zinc for the mean number of episodes of OM (mean difference (MD) -1.12 episodes, 95% CI -2.21 to -0.03). Zinc supplements did not seem to cause any serious adverse events but a small minority of children were reported to have vomited shortly after ingestion of the supplements. The trial evidence included is generally of good quality, with a low risk of bias.

AUTHORS' CONCLUSIONS

Evidence on whether zinc supplementation can reduce the incidence of OM in healthy children under the age of five years living in low- and middle-income countries is mixed. There is some evidence of benefit in children being treated for marasmus (severe malnutrition) but this is based on one small trial and should therefore be treated with caution.

Efeitos da deficiência de cobre, zinco e magnésio sobre o sistema imune de crianças com desnutrição grave

OBJETIVO: Esclarecer as repercussões da deficiência de cobre, zinco e magnésio sobre o sistema imune de crianças desnutridas graves. FONTES DE DADOS: Foi realizada revisão bibliográfica mediante consulta às bases de dados Pubmed Medline, Lilacs e SciELO, selecionando-se publicações científicas recentes, da última década, e representativas do tema por meio dos descritores: desnutrição infantil, cobre, zinco, magnésio e sistema imune. SÍNTESE DE DADOS: Os micronutrientes são compostos orgânicos essenciais. Além de sua função regulatória, atuam de maneira decisiva na modulação da resposta imune. Sua deficiência pode ocorrer devido à ingestão inadequada ou associada a doenças específicas. Quando associada à desnutrição, a multideficiência de minerais pode acarretar disfunções imunológicas e aumento na suscetibilidade a infecções, afetando gravemente a eficácia de intervenções terapêuticas. Cobre, zinco e magnésio atuam como cofatores de enzimas responsáveis tanto por diversas atividades metabólicas como na resposta imune inata e adquirida, além do papel importante na maturação dos tecidos e células linfoides. Sua deficiência acarreta neutropenia e linfopenia, comprometendo a imunocompetência. CONCLUSÕES: As alterações ocasionadas pelos déficits séricos dos minerais cobre, zinco e magnésio comprometem o funcionamento do sistema imune, levando à imunossupressão. A reposição desses elementos no manejo da desnutrição grave, como preconizada pela Organização Mundial da Saúde, é essencial, uma vez que tais alterações podem ser reversíveis.

Zinc supplementation in children is not associated with decreases in hemoglobin concentrations

Zinc supplementation has proven beneficial in the treatment of acute child diarrhea and appears to enhance linear growth. There is a theoretical risk of anemia in zinc-supplemented children due to inhibited iron transport via decreased copper absorption. Although many zinc supplementation trials have included hematological measures, the potential effect of zinc on these outcomes has not been quantitatively evaluated in a comprehensive review. We performed a systematic review of randomized trials that examined the effect of zinc supplementation on hemoglobin concentrations in apparently healthy children ages 0-15 y and conducted a random effects meta-analysis of weighted mean differences (WMD) of change in hemoglobin concentrations before and after supplementation. Twenty-one randomized, controlled trials representing 3869 participants were included in the meta-analysis. The duration of treatment ranged from 4 to 15 mo; doses were typically 10-20 mg/d. Zinc supplementation did not affect changes in hemoglobin concentrations (pooled WMD: 0.8 g/L; 95% CI: -0.6, 2.2; P = 0.27). There was no evidence for effect modification by age, zinc dosage, duration of treatment, type of control, baseline hemoglobin status, geographical or healthcare setting, or quality of the studies. These results suggest that zinc supplementation at doses typically used in randomized trials is a safe intervention with regards to hemoglobin concentrations. Some benefits might exist among children with severe anemia or zinc deficiency, which warrant further evaluation.

Zinc supplements for preventing otitis media

BACKGROUND

Otitis media (inflammation of the middle ear, usually caused by infection) affects people of all ages, but is particularly common in young children. Around 164 million people worldwide have long-term hearing loss caused by this condition, 90% of them in low-income countries. Because zinc supplements prevent pneumonia in disadvantaged children, we wondered whether they prevent otitis media.

OBJECTIVES

To evaluate whether zinc supplements prevent otitis media in adults and children of different ages.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2009, issue 2) which includes the Acute Respiratory Infection Groups' Specialised Register; MEDLINE (1950 to June Week 1 2009); and EMBASE (1974 to June 2009).

SELECTION CRITERIA

Randomised, placebo-controlled trials of zinc supplements given at least once a week for at least a month for preventing otitis media.

DATA COLLECTION AND ANALYSIS

Two review authors assessed the eligibility and methodological quality of the included trials, extracted and analysed data and wrote the review. We summarised results using risk ratios or rate ratios for dichotomous data and mean differences for continuous data. We combined trial results where appropriate.

MAIN RESULTS

We identified 12 trials for inclusion, 10 of which contributed outcomes data. In trials of healthy children living in low-income communities, two trials did not demonstrate a significant difference between the zinc supplemented and placebo groups in the numbers of participants experiencing an episode of definite otitis media during follow up (3191 participants), while another trial showed a significantly lower incidence rate of otitis media in the zinc group (rate ratio 0.69, 95% confidence interval (CI) 0.61 to 0.79, n = 1621). A small trial of 39 infants undergoing treatment for severe malnutrition suggested a benefit of zinc on the mean number of episodes of otitis media (mean difference -1.12 episodes, 95% CI -2.21 to -0.03). Zinc supplements did not seem to cause any serious adverse events, but a small minority of children were reported to have vomited shortly after ingestion of the supplements.

AUTHORS' CONCLUSIONS

Evidence on whether zinc supplementation can reduce the incidence of otitis media in healthy children under the age of five years living in low- and middle-income countries is mixed. There is some evidence of benefit in children being treated for marasmus, but this is based on one small trial and should therefore be treated with caution.

Oral zinc for treating diarrhoea in children

BACKGROUND

Diarrhoea causes around two million child deaths annually. Zinc supplementation could help reduce the duration and severity of diarrhoea, and is recommended by the World Health Organization and UNICEF.

OBJECTIVES

To evaluate oral zinc supplementation for treating children with acute or persistent diarrhoea.

SEARCH STRATEGY

In November 2007, we searched the Cochrane Infectious Diseases Group Specialized Register, CENTRAL (The Cochrane Library 2007, Issue 4), MEDLINE, EMBASE, LILACS, CINAHL, mRCT, and reference lists. We also contacted researchers.

SELECTION CRITERIA

Randomized controlled trials comparing oral zinc supplementation (>/= 5 mg/day for any duration) with placebo in children aged one month to five years with acute or persistent diarrhoea, including dysentery.

DATA COLLECTION AND ANALYSIS

Both authors assessed trial eligibility and methodological quality, extracted and analysed data, and drafted the review. Diarrhoea duration and severity were the primary outcomes. We summarized dichotomous outcomes using risk ratios (RR) and continuous outcomes using mean differences (MD) with 95% confidence intervals (CI). Where appropriate, we combined data in meta-analyses (using the fixed- or random-effects model) and assessed heterogeneity.

MAIN RESULTS

Eighteen trials enrolling 6165 participants met our inclusion criteria. In acute diarrhoea, zinc resulted in a shorter diarrhoea duration (MD -12.27 h, 95% CI -23.02 to -1.52 h; 2741 children, 9 trials), and less diarrhoea at day three (RR 0.69, 95% CI 0.59 to 0.81; 1073 children, 2 trials), day five (RR 0.55, 95% CI 0.32 to 0.95; 346 children, 2 trials), and day seven (RR 0.71, 95% CI 0.52 to 0.98; 4087 children, 7 trials). The four trials (1458 children) that reported on diarrhoea severity used different units and time points, and the effect of zinc was less clear. Subgroup analyses by age (trials with only children aged less than six months) showed no benefit with zinc. Subgroup analyses by nutritional status, geographical region, background zinc deficiency, zinc type, and study setting did not affect the results' significance. Zinc also reduced the duration of persistent diarrhoea (MD -15.84 h, 95% CI -25.43 to -6.24 h; 529 children, 5 trials). Few trials reported on severity, and results were inconsistent. No trial reported serious adverse events, but vomiting was more common in zinc-treated children with acute diarrhoea (RR 1.71, 95% 1.27 to 2.30; 4727 children, 8 trials).

AUTHORS' CONCLUSIONS

In areas where diarrhoea is an important cause of child mortality, research evidence shows zinc is clearly of benefit in children aged six months or more.

Pneumonia research to reduce childhood mortality in the developing world

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

Zinc or multiple micronutrient supplementation to reduce diarrhea and respiratory disease in South African children: a randomized controlled trial

Background

Prophylactic zinc supplementation has been shown to reduce diarrhea and respiratory illness in children in many developing countries, but its efficacy in children in Africa is uncertain.

Objective

To determine if zinc, or zinc plus multiple micronutrients, reduces diarrhea and respiratory disease prevalence.

Design

Randomized, double-blind, controlled trial.

Setting

Rural community in South Africa.

Participants

Three cohorts: 32 HIV-infected children; 154 HIV-uninfected children born to HIV-infected mothers; and 187 HIV-uninfected children born to HIV-uninfected mothers.

Interventions

Children received either 1250 IU of vitamin A; vitamin A and 10 mg of zinc; or vitamin A, zinc, vitamins B1, B2, B6, B12, C, D, E, and K and copper, iodine, iron, and niacin starting at 6 months and continuing to 24 months of age. Homes were visited weekly.

Outcome Measures

Primary outcome was percentage of days of diarrhea per child by study arm within each of the three cohorts. Secondary outcomes were prevalence of upper respiratory symptoms and percentage of children who ever had pneumonia by maternal report, or confirmed by the field worker.

Results

Among HIV-uninfected children born to HIV-infected mothers, median percentage of days with diarrhea was 2.3% for 49 children allocated to vitamin A; 2.5% in 47 children allocated to receive vitamin A and zinc; and 2.2% for 46 children allocated to multiple micronutrients (P = 0.852). Among HIV-uninfected children born to HIV-uninfected mothers, median percentage of days of diarrhea was 2.4% in 56 children in the vitamin A group; 1.8% in 57 children in the vitamin A and zinc group; and 2.7% in 52 children in the multiple micronutrient group (P = 0.857). Only 32 HIV-infected children were enrolled, and there were no differences between treatment arms in the prevalence of diarrhea. The prevalence of upper respiratory symptoms or incidence of pneumonia did not differ by treatment arms in any of the cohorts.

Conclusion

When compared with vitamin A alone, supplementation with zinc, or with zinc and multiple micronutrients, did not reduce diarrhea and respiratory morbidity in rural South African children.

Trial Registration

ClinicalTrials.gov NCT00156832

Effect of zinc supplementation on mortality in children aged 1-48 months: a community-based randomised placebo-controlled trial

BACKGROUND

Studies from Asia have suggested that zinc supplementation can reduce morbidity and mortality in children, but evidence from malarious populations in Africa has been inconsistent. Our aim was to assess the effects of zinc supplementation on overall mortality in children in Pemba, Zanzibar.

METHODS

We enrolled 42,546 children aged 1-36 months, contributing a total of 56,507 child-years in a randomised, double-blind, placebo-controlled trial in Pemba, Zanzibar. Randomisation was by household. 21 274 children received daily supplementation with zinc 10 mg (5 mg in children younger than 12 months) for mean 484.7 days (SD 306.6). 21,272 received placebo. The primary endpoint was overall mortality, and analysis was by intention to treat. This study is registered as an International Standard Randomised Clinical Trial, number ISRCTN59549825.

FINDINGS

Overall, there was a non-significant 7% (95% CI -6% to 19%; p=0.29) reduction in the relative risk of all-cause mortality associated with zinc supplementation.

INTERPRETATION

We believe that a meta-analysis of all studies of mortality and morbidity, will help to make evidence-based recommendations for the role of zinc supplementation in public health policy to improve mortality, morbidity, growth, and development in young children.

Critical appraisal of the management of severe malnutrition: 2. Dietary management

In the dietary management of severe acute malnutrition in children, there is evidence to support the WHO Manual's protocol of cautious feeding of a low energy and protein formula with small frequent feeds in the initial phase of treatment, particularly in kwashiorkor. However, this initial milk diet (WHO F-75) might benefit from increasing the sulphur amino acid, phosphorus and potassium content and reducing the lactose content, but further studies are needed. Careful tube-feeding results in faster initial recovery and weight gain, but has a significant risk of aspiration in poorly supervised settings. Ready-to-use therapeutic food is an important recent advance in the dietary management of malnutrition in ambulatory settings, allowing more effective prevention programmes and earlier discharge from hospital where community follow-up is available. It should be included in future protocols. There is very good evidence on the use of micronutrients such as zinc, and preliminary evidence suggests that smaller doses of daily vitamin A are preferable to a single large dose on admission for severe malnutrition.

Zinc in child health and disease

Zinc deficiency is common in children from developing countries due to lack of intake of animal foods, high dietary phytate content, inadequate food intake and increased fecal losses during diarrhea. Zinc has a fundamental role in cellular metabolism, with profound effects on the immune system and the intestinal mucosa. Zinc supplementation has shown significant benefits in prevention and treatment of diarrhea and pneumonia. Routine zinc supplementation given to low birth weight babies for a year has resulted in substantial reduction in mortality. Zinc deficiency may have adverse effects on physical growth and neurodevelopment. WHO Task Force, 2001, and the National task Force of IAP has recommended use of zinc in the treatment of diarrhea. It is also recommended as part of standard case management in persistent diarrhea and in those with severe malnutrition. Further evidence is required for qualifying its use in treatment of other infective diseases like pneumonia and malaria. Improved dietary quality & intake, food fortification and cultivation of zinc dense plants are some ways of mitigating zinc deficiency.