Role of Zinc in Recurrent Acute Lower Respiratory Infections

Acute respiratory infections (ARIs) are the most frequent illnesses globally. Despite advances in the recognition and management ARIs, these account for over 20% of all child deaths globally.Trace mineral deficiencies have long been implicated in causation and consequences of many diseases. The importance of adequate zinc intake in human health is well documented and zinc deficiency is a large public health problem, especially among children in developing countries.Various studies suggest that zinc-deficient populations are at increased risk of developing diarrhoeal diseases, respiratory tract infections and growth retardation.Among the individual interventions zinc supplementation with universal coverage ranks 5th in preventing under five mortality in India, preceded only in order by breast feeding; complementary feeding; clean delivery; Hib vaccination; and clean water, sanitation and hygiene.Numerous studies have examined the association between child mortality and zinc deficiency. A number of randomized controlled trials evaluating effect of zinc supplementation have found the intervention to be beneficial in reducing ARI and diarrhoeal mortality and morbidity but few studies have found beneficial effect in diarrhea and no or even contrasting effects on morbidity pattern of acute respiratory infections. Whereas role of zinc in diarrhea is now a well established and specific guidelines and recommendations have been given for zinc supplementation in diarrhea, role of zinc in acute respiratory infections is controversial. The contrasting effect of zinc on diarrhoea and acute lower respiratory infection as reported in several studies is a public health concern, because zinc supplementation is carried out in many nutrition rehabilitation units. Further in many of randomized control trials supplement syrups also contained other vitamins, including vitamin A, known to have effect on respiratory morbidity. Most of the trials evaluating effect of zinc on respiratory morbidity and mortality are community based and children with well known causes of recurrent acute lower respiratory infections have not been excluded from the study pool.

Hence the current study was planned to bridge this gap of information and attempts to detect the role of zinc using "zinc only preparations" in reducing respiratory morbidity in children aged 6 to 59 months with recurrent acute lower respiratory infections.