title: [Increased occurrence of allergy--is modern life style the cause?].
abstract: BACKGROUND
  There is strong evidence that an increase in the occurrence of allergic diseases has taken place in industrialised countries over the last decades. The causes of this increase are unknown, but it seems to be linked to affluence and a modern, "westernized" lifestyle.
  
  
  METHODS
  Three international research papers are reviewed and discussed in the context of current knowledge of immunoregulatory effects from microbial and allergen exposure.
  
  
  RESULTS
  A German report indicates that early attendance (before one year of age) at daycare centres reduced the risk for allergy development in children from small, but not from large families. A Swiss and a Swedish paper report that children of farmers, or students attending anthroposophic Steiner schools had less allergic manifestations than their peers in the same local communities.
  
  
  CONCLUSIONS
  The findings suggest that groups practising a somewhat simple, "old-fashioned" lifestyle within a modern community have a reduced risk of developing allergic diseases. Proper microbial stimulation of the immune system, possibly via the bacterial flora on the mucosal surfaces of the upper airways and the gut, may act to reduce the risk of becoming allergic. Insufficient microbial stimulation of the immune system may be a "deficiency disease" of modern society, leading to allergy.
authors.affiliation: Avdeling for miljømedisin, Statens institutt for folkehelse, Postboks 4404 Torshov 0403 Oslo. martinus.lovik@folkehelsa.no
authors.forename: M
authors.initials: M
authors.lastname: Løvik
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D004781:Environmental Exposure / Q000009:adverse effects*; D004783:Environmental Microbiology; D005858:Germany / Q000453:epidemiology; D006801:Humans; D006967:Hypersensitivity / Q000453:epidemiology* / Q000209:etiology / Q000276:immunology; D006969:Hypersensitivity, Immediate / Q000453:epidemiology / Q000209:etiology / Q000276:immunology; D008019:Life Style; D015995:Prevalence; D012307:Risk Factors; D013548:Sweden / Q000453:epidemiology; D013557:Switzerland / Q000453:epidemiology