Can the 'hygiene hypothesis' be explained by confounding by behavior?
van Schayck
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CP
Care and Public Health Research Institute, University of Maastricht, P.O. Box 616 6200, MD Maastricht, The Netherlands. O.vanSchayck@caphri.unimaas.nl
Knottnerus
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JA
D001249:Asthma / Q000276:immunology; D015986:Confounding Factors, Epidemiologic; D015438:Health Behavior; D006801:Humans; D006920:Hygiene; D006967:Hypersensitivity / Q000209:etiology / Q000517:prevention & control*; D007239:Infections / Q000276:immunology