Preventive zinc supplementation in developing countries: impact on mortality and morbidity due to diarrhea, pneumonia and malaria

Abstract

BackgroundZinc deficiency is commonly prevalent in children in developing countries and plays a role in decreased immunity and increased risk of infection. Preventive zinc supplementation in healthy children can reduce mortality due to common causes like diarrhea, pneumonia and malaria. The main objective was to determine all-cause mortality and cause-specific mortality and morbidity in children under five in developing countries for preventive zinc supplementation.Data sources/ review methodsA literature search was carried out on PubMed, the Cochrane Library and the WHO regional databases to identify RCTs on zinc supplementation for greater than 3 months in children less than 5 years of age in developing countries and its effect on mortality was analyzed.ResultsThe effect of preventive zinc supplementation on mortality was given in eight trials, while cause specific mortality data was given in five of these eight trials. Zinc supplementation alone was associated with a statistically insignificant 9% (RR = 0.91; 95% CI: 0.82, 1.01) reduction in all cause mortality in the intervention group as compared to controls using a random effect model. The impact on diarrhea-specific mortality of zinc alone was a non-significant 18% reduction (RR = 0.82; 95% CI: 0.64, 1.05) and 15% for pneumonia-specific mortality (RR = 0.85; 95% CI: 0.65, 1.11). The incidence of diarrhea showed a 13% reduction with preventive zinc supplementation (RR = 0.87; 95% CI: 0.81, 0.94) and a 19% reduction in pneumonia morbidity (RR = 0.81; 95% CI: 0.73, 0.90). Keeping in mind the direction of effect of zinc supplementation in reducing diarrhea and pneumonia related morbidity and mortality; we considered all the outcomes for selection of effectiveness estimate for inclusion in the LiST model. After application of the CHERG rules with consideration to quality of evidence and rule # 6, we used the most conservative estimates as a surrogate for mortality. We, therefore, conclude that zinc supplementation in children is associated with a reduction in diarrhea mortality of 13% and pneumonia mortality of 15% for inclusion in the LiST tool. Preventive zinc supplementation had no effect on malaria specific mortality (RR = 0.90; 95% CI: 0.77, 1.06) or incidence of malaria (RR=0.92; 95 % CI 0.82-1.04)ConclusionZinc supplementation results in reductions in diarrhea and pneumonia mortality.

Efecto del zinc aminoquelado y el sulfato de zinc en la incidencia de la infección respiratoria y la diarrea en niños preescolares de centros infantiles

“…El zinc juega un papel trascendente en el mantenimiento de la integridad celular y de la inmunidad, con una acción fundamental en el control y prevención de las infecciones (1,12), ya que es un potente mediador en la resistencia del huésped (20)(21)(22). En el ámbito social, la deficiencia de zinc en países de bajos ingresos va ligada a situaciones como la pobreza, el hacinamiento y la ausencia de servicios públicos que elevan la vulnerabilidad de los niños; esto sumado a esquemas alimentarios inadecuados que generan deficiencia de minerales como el zinc, predispone a un mayor riesgo y gravedad de una variedad de enfermedades infecciosas (1,2,23).…”

“…El uso de zinc como una terapia adjunta en el tratamiento de la diarrea aguda mejora la eficacia del manejo y se convierte en una acción costoefectiva comparada con el manejo estándar de la diarrea (8,9).De igual forma, varios metaanálisis han demostrado que podría disminuir la incidencia de la diarrea aguda cuando se toma por varias semanas (10)(11)(12); no obstante, su uso en la prevención no está aprobado. Respecto a la infección respiratoria aguda, varios metaanálisis han mostrado resultados contradictorios tanto en el tratamiento como en la prevención de la neumonía y del resfriado común con suplementos de zinc (10,(12)(13)(14) .…”

“…Respecto a la infección respiratoria aguda, varios metaanálisis han mostrado resultados contradictorios tanto en el tratamiento como en la prevención de la neumonía y del resfriado común con suplementos de zinc (10,(12)(13)(14) .…”

Zinc supplementation in children and adolescents with acute leukemia

“…34,35 It has been reported, for example, that zinc supplementation attenuates the symptoms of common cold, can accelerate recovery from pneumonia and other bacterial diseases and reduces diarrhea morbidity. 4,5,36 Besides, it is well known that during chemotherapy, a risk for such complications becomes higher, sometimes leading to treatment discontinuation. In adult patients receiving radiotherapy, oral zinc supplementation prevents opportunistic bacterial and fungal infections.…”

“…The beneficial effects of its supplementation in children in the management of infantile diarrhea, acute respiratory infections and pneumonia are evidenced by decreased morbidity and mortality. 4,5 Zinc supplementation manifests significant positive effects on linear growth, especially when administered alone, and hence it was strongly recommended in the National Health Service strategies in order to reduce stunting in children o5 years of age. 6 It was logical to believe that zinc might also be useful in patients undergoing chemotherapy for acute leukemia and its consecutive complications.…”