User:Bettchlk618/Environmental enteropathy

Epidemiology
Environmental enteropathy (EE) primarily affects children living in low- and middle-income countries (LMICs). Children living in these countries were found to have enteric pathogens related to EE in their systems throughout much of their early childhoods. Gastrointestinal abnormalities associated with EE are not congenital but are acquired during infancy and persist into adulthood. Such abnormalities tend to develop after the first semester of life and are not present in newborns.

Historically, environmental enteropathy has been prevalent in LMICs. The geographic distribution of environmental enteropathy has shown an increase in incidence in such areas of poor sanitation and hygiene. EE was first described in studies from the 1960-70s conducted in Asia, Africa, the Indian subcontinent, and Central America, during which it was discovered that signs of EE were high among otherwise healthy adults and children. A study from 1971 following US Peace Corps volunteers is often cited as being the first study to demonstrate the ability to acquire and recover from EE according to the environment. Participants experienced symptoms of chronic enteric infection during and shortly after returning from their placement in low- and middle-income countries. Symptoms experienced by those abroad were resolved within one to two years after returning home to the US. These results lead to the suggestion of the environment being a cause of EE, and a later study in Zambia was able to draw similar conclusions. By the early 1990s, environmental enteropathy was found to be a widespread problem affecting infants and children. Today, enteric infections and diarrheal diseases like environmental enteropathy account for 760,000 deaths per year worldwide, making EE the second leading cause of death in children under five years old.

The exact causes and consequences of EE have been difficult to establish due, in part, to the lack of a clear disease definition. However, risk factors do exist and they can be both environmental and nutritional. Preexisting conditions such as micronutrient deficiencies, diarrheal diseases, and various chronic infections all serve as risk factors for EE. Environmental conditions such as poor sanitation and unimproved water sources also contribute to the prevalence of EE. Exposure to environmental microbial agents such as these is thought to be the most important factor in the development of EE.