Zinc research at ICDDR,B

Over the past two decades significant progress has been made in our understanding of the impact of zinc deficiency on child health and the potential of zinc treatment in reducing childhood morbidity and mortality from infectious diseases. Studies have demonstrated effectiveness of zinc supplements in reducing incidence of pneumonia and diarrhoea, the most common causes of death among children living in developing countries. These, in turn, interact with malnutrition to create a vicious spiral of recurrent infection and progressive health decline, often resulting in death from otherwise common childhood illnesses, such as measles. Zinc supplementation among these children holds tremendous potential as a global public health intervention.

With support and funding from the Child Health Research (CHR) Project, ICDDR,B (the Centre) has been among the frontline research organizations conducting zinc research, stimulating other national and international research institutes to follow. Studies conducted at the Centre, from basic to applied research, have helped to build an evidence base for integrating zinc therapy into current child health practice and policies, such as the WHO recommendation for the use of zinc in the treatment of persistent diarrhoea. Findings have received various levels of international attention, but all have been fundamental contributions to the core of global knowledge on zinc. Highlights of some of the major studies follow.

·         Dr. SK Roy conducted a study to evaluate the impact of zinc supplementation on the clinical recovery and body weight of children with persistent diarrhoea aged between 3 and 24 months. Findings documented that zinc supplementation in persistent diarrhoea significantly reduced the length of the recovery period in malnourished children and prevented a fall in body weight and serum zinc concentration, indicating that zinc is a beneficial therapeutic strategy in this high-risk childhood illness. (read more …)

·         Dr. Abdullah Brooks conducted a study in an urban population in Dhaka, in which children under 2 years old were given 70 mg of zinc weekly, or a placebo, for a 12 month supplementation period to determine if this type of preventive strategy would reduce rates of illness. Children who received zinc experienced a 20% reduction in pneumonia, a 49% reduction in severe pneumonia and 6.6-fold reduction in mortality, explained almost entirely by a reduction in deaths due to pneumonia and diarrhoea, thus adding support to the mortality benefits of routine zinc.  

·         Dr. Abdullah Baqui conducted a study in Matlab in which clusters of children were randomly assigned to receive zinc, 20 mg daily for 14 days, with each episode of diarrhoea. After two years of follow-up, the clusters receiving zinc experienced a 50% reduction in overall non-injury mortality compared to those receiving standard therapy without zinc. (read more …)

·         Dr. Rubhana Raqib conducted a trial to study the effect of short-term zinc supplementation on essential and specific immune and inflammatory responses in moderately malnourished children with acute shigellosis. Results showed that 2 weeks of 20 mg zinc supplementation in acute shigellosis enhances antigen-specific antibody and lymphocyte proliferation responses in peripheral circulation. This data suggest that a short course of zinc may be equally beneficial in boosting immune responses as a prolonged course. This is particularly relevant for feasible and cost-effective therapies for shigellosis in developing countries where the disease is prevalent. (Manuscript in preparation.)

·         Dr. Brooks carried out a study of the efficacy of zinc as adjuvant therapy for severe pneumonia among hospitalized children less than two years old. This placebo-controlled trial showed that 20 mg/day of zinc, when added to the standard treatment of antibiotics, decreased recovery time from severe pneumonia and the time in hospital by 20% substantially reduced the rate of treatment failure with standard antibiotic management. (read more ...)

·         Dr. Saskia Osendarp conducted a study to determine the effects of zinc supplementation during pregnancy on infant growth, morbidity and immune responses in two cohorts of infants whose mothers took 30 mg daily elemental zinc or placebo, respectively, from 12 to 16 weeks’ gestation until delivery. Infants of mothers who received zinc during pregnancy had at age 6 months reduced risks compared with those in the placebo group for acute diarrhoea, dysentery, and impetigo. These reductions were seen in low-birthweight infants but not in those with normal birthweight. There were no differences in infant growth or serum zinc concentrations between treatment groups. (read more …)

·         Dr. Abdullah Baqui carried out a study in Matlab to determine the effectiveness of a weekly supplementation of iron, zinc, simultaneous iron and zinc and a micronutrient mix on diarrhoea and ALRI morbidity in infants aged 6-12 months. Less nourished infants receiving both iron and zinc had a 30% lower incidence of diarrhoea.  Zinc alone was associated with lower diarrhoea and ALRI morbidity in less-nourished infants, but the differences were not significant. Iron supplementation alone had no effect on diarrhoea and ALRI morbidity. Children receiving micronutrient mix had significantly higher risk of diarrhoea. Three manuscripts have been prepared and submitted for publication. The findings are expected to contribute to the debate on the use of specific micronutrients and micronutrient mixes as prophylaxis for children. (read more …)

·         Dr. Shams El Arifeen examined the effect of zinc supplementation on the immune response to Rotashield™ rotavirus vaccine in rural Bangladeshi infants.Infants were randomized to receive the vaccine either with or without previous supplementation with zinc.In this placebo controlled study, those receiving the zinc had a better serum antibody response than did those not receiving zinc in those children who were lighter weight, suggesting that relatively malnourished children might especially benefit from zinc.

·         Dr. Ferdausi and others conducted a study to determine whether micronutrient supplementation could improve the vibriocidal antibody response of children to an oral cholera vaccine. 2 to 5-year-old children received vitamin A and zinc (AZ group), vitamin A and a placebo (A group), zinc and a placebo (Z group), or both placebos (P group). All children received 2 doses of the vaccine. The number of children who had a greater or equal 4-fold increase in vibriocidal antibody was greater in the AZ group than in the P group. The proportion of children with a greater or equal 4-fold increase in vibriocidal antibody titer was significantly greater in the zinc-supplemented groups than in the groups that did not receive zinc. Thus, supplementation with zinc improves seroconversion to vibriocidal antibody and, hence, has the potential to improve the efficacy of oral cholera vaccine in children. (read more …)

·         Dr SK Roy conducted a study to assess the impact of zinc supplementation on clinical recovery, weight gain and subsequent growth and morbidity in moderately malnourished children with shigellosis. The age of the children were from 12–59 months with culture-proven shigellosis. After supplementation, children were followed in their respective homes every 2 weeks for 6 months. The study findings show that zinc supplementation significantly shortens the duration of acute shigellosis, promotes better weight gain during recovery and reduces diarrhoeal morbidity during the subsequent 6 months.