Zinc supplementation and child mortality in Zanzibar

Zinc and child mortality.

Pneumonia, diarrhoea, and malaria account for 45% of the 10-6 million yearly deaths of children younger than 5 years despite some success with preventive and therapeutic interventions. 2-6 million of these deaths take place in Africa, including 90% of the 0-8 million worldwide childhood malaria deaths every year. Finding cheap methods for reducing such mortality, would help countries achieve the Millennium Development Goal of two-thirds reduction in child mortality. The cost of this awful mortality rate does not also take into account the danger to the mothers of these children in the pregnancy where there is also a significant death rate and morbidity e.g. fistula.
Deficiency of a few essential micronutrients is recognised to greatly increase the risk of morbidity and mortality from infectious diseases in developing countries. Evidence for zinc as one such important micronutrient has emerged; in addition to data linking zinc deficiency to growth retardation and impairment of immune function, zinc supplementation has shown significant reduction in rates and severity of diarrhoea and pneumonia, (the two main causes of under-5 mortality). Three small trials in-Asian populations without malaria showed that zinc supplementation significantly reduced child mortality. Evidence for the benefit of zinc supplementation on malaria morbidity has been inconsistent. Sazawal and his colleagues
(Lancet , 369, 927-933) undertook a community-based trial to assess the effect of zinc supplementation on mortality in children aged 1-48 months in Pemba, Zanzibar, a place with a high-frequency of malaria transmission.
There were 42,546 children in the study, and the result was a 7% reduction in the relative risk associated with zinc supplementation.
Such studies are fraught with problems ( Bhatnagar in Lancet 2007, 369, 885-6). The dosage of zinc varies, the type of zinc preparation and bioavailability varies, compliance must be a problem from small to large studies and the study populations. At least in this study there was an improvement , in some vitamin / cancer studies the mortality has risen.
At the end of this stage of the economy in these countries, zinc ,and oral rehydration fluids possibly vitamin A availability are important community strategies to reduce the death toll.
An adequate clean diet and fluid is the real end objective.

Martin Eastwood

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