title: Hay fever, asthma, and eczema and early infectious diseases among children in Kilimanjaro, Tanzania.
abstract: OBJECTIVE
  To investigate the hygiene (or "old friends") hypothesis in a high-infectious disease (ID) environment, rural Kilimanjaro, Tanzania.
  
  
  METHODS
  Among a cross-sectional sample of 2- to 7-year-old children, we collected physician-diagnosed hay fever, asthma, and eczema, history of hospitalization, family size, and household environment information via questionnaire; performed active and passive surveillance for ID; and, evaluated total immunoglobulin E (IgE) and biomarkers of inflammation in dried blood spot specimens. We used regression models to describe patterns in allergic diseases.
  
  
  RESULTS
  Complete information was available for 280 children: 12.5% had been diagnosed with hay fever; 18.9% with eczema; 2.1% with asthma. There was a positive association between hay fever and eczema diagnoses (π2: 4.07; P = 0.044); total IgE was positively associated with eczema (β: 0.24; P = 0.100) and allergic diseases together (β: 0.26; P = 0.042). ID were common: the incidence of any ID diagnosis was 28 per 100 children per month. Hay fever was inversely associated with household animals (OR: 0.27; P = 0.006), and positively associated with earth housing materials (OR: 1.93; P = 0.079) and hospitalization in infancy with an ID (3.16; P = 0.066); patterns were similar when allergic disease outcomes were considered together. Few associations between these predictors and eczema or asthma alone were apparent.
  
  
  CONCLUSIONS
  Allergic diseases were common among children in Kilimanjaro. The inverse association between household animals and allergy is consistent with the hygiene/old friends hypothesis; however, positive associations between allergic diseases and earth housing materials and early hospitalization with ID bear further explanation.
authors.affiliation: Department of Anthropology, Binghamton University (SUNY), Binghamton, New York, 13902.|Department of Anthropology, University of Washington, Seattle, Washington, 98195.|Center for Studies in Demography and Ecology, University of Washington, Seattle, Washington, 98195.
authors.forename: Katherine
authors.identifier: http://orcid.org/0000-0002-4913-5075
authors.initials: K
authors.lastname: Wander
authors.affiliation: Department of Anthropology, University of Washington, Seattle, Washington, 98195.|Center for Studies in Demography and Ecology, University of Washington, Seattle, Washington, 98195.
authors.forename: Bettina
authors.initials: B
authors.lastname: Shell-Duncan
authors.affiliation: Center for Studies in Demography and Ecology, University of Washington, Seattle, Washington, 98195.
authors.forename: Eleanor
authors.identifier: http://orcid.org/0000-0002-4272-0909
authors.initials: E
authors.lastname: Brindle
authors.affiliation: Department of Anthropology, University of Washington, Seattle, Washington, 98195.|Center for Studies in Demography and Ecology, University of Washington, Seattle, Washington, 98195.
authors.forename: Kathleen
authors.initials: K
authors.lastname: O'Connor
mesh_terms: D001249:Asthma / Q000453:epidemiology* / Q000209:etiology; D002648:Child; D002675:Child, Preschool; D003141:Communicable Diseases / Q000453:epidemiology* / Q000209:etiology; D003430:Cross-Sectional Studies; D004485:Eczema / Q000453:epidemiology* / Q000209:etiology; D005260:Female; D006801:Humans; D006920:Hygiene; D008297:Male; D015995:Prevalence; D006255:Rhinitis, Allergic, Seasonal / Q000453:epidemiology* / Q000209:etiology; D013636:Tanzania / Q000453:epidemiology