Nutrition, Growth and Infectious disease

Child Health and Development in Kilimanjaro

Children under the age of five are particularly vulnerable to disease, and subject to higher rates of mortality than older children and adults. Health insults during these early years of life can have lasting consequences for children, many of which researchers are only beginning to understand.

Young children are among those most vulnerable to infectious disease. Infectious diseases in children can have both short- and long-term consequences: infections can cause blood loss and destroy blood cells, resulting in anemia; diarrhea and other aspects of infectious diseases can interfere with digestion and absorption of nutrients, resulting in malnutrition; and, fighting infectious disease can make tremendous energetic demands of the immune system—these factors can all compromise growth, and other aspects of cognitive development. Infectious diseases during childhood can also alter the development of the immune system, affecting risk for allergic and autoimmune diseases, as well as the capacity to respond appropriately to infection.

Binghamton University faculty member Katherine Wander is investigating multiple health stressors and their lasting impact on child health and development in Kilimanjaro, Tanzania. Her initial phases of research found that, among children in Kilimanjaro, infectious diseases are very common, even more common than is typically observed among children in Tanzania or East African in general. Early infectious diseases are related to health outcomes later in childhood among Kilimanjaro children: both immune responses to infectious agents and allergic immune responses are stronger among children who were hospitalized with pneumonia or malaria during infancy, for example.

Malnutrition is also common among children in Kilimanjaro. The prevalence of wasting (indicative of starvation) and stunting (indicative of chronic energy shortage) in Kilimanjaro is lower than for Tanzania as a whole, as are rates of low birth weight; nonetheless, the prevalence of stunting is high (~20%), indicating that many children's energy and protein intake falls short of that needed to maintain healthy growth. Rates of deficiency in the micronutrient iron are high (~30%), as are rates of anemia (~30%) among Kilimanjaro children. There seems to be a complex relationship between iron deficiency and infectious disease in Kilimanjaro: Some infectious diseases, such as hookworm and schistosomiasis, can cause anemia and iron deficiency via blood loss. Other infectious diseases, such as respiratory infections, occur at lower incidence among children with mild-to-moderate iron deficiency; their lower iron intake may limit iron availability to some pathogens, and protect against disease.

Professor Wander's ongoing data collection in Kilimanjaro will continue to elucidate the complex interactions between infectious diseases, immunity, and nutrition with longitudinal data collection among Kilimanjaro children and their families. Some of the questions to be addressed include:

How much does a helminth infection (e.g., hookworm, schistosomiasis, or intestinal roundworm) increase risk for iron deficiency and anemia? How much iron deficiency and anemia do helminths cause among Kilimanjaro children?

Does mild-to-moderate iron deficiency (not severe enough to result in anemia) decrease risk for any infectious diseases (e.g., upper or lower respiratory tract infection, diarrheal disease, malaria)?

Does iron deficiency (particularly mild-to-moderate iron deficiency) affect immune responses?

Do we see "trade-offs" between different categories of immune responses: Type 1 (those against viruses, bacteria, protozoa), type 2 (those against helminths), or immunoregulation (which controls potentially damaging inflammation and pathological Type 1 and 2 responses)? How are these "trade-offs" affected by early infectious diseases, if at all?