High exposure to endotoxin in farming is associated with less new-onset pollen sensitisation

Grethe Elholm, Vivi Schlünssen, Gert Doekes, Ioannis Basinas, Anneli Clea Skjelmose Bolund, Charlotte Hjort, Pernille Milvang Grønager, Øyvind Omland, Torben Sigsgaard

Research output: Contribution to journalArticlepeer-review


OBJECTIVES: Little is known about risk factors for new onset and loss of atopic sensitisation in adulthood. The aim is to examine the longitudinal effect of quantitatively assessed endotoxin exposures on changes in specific allergen sensitisation in young adults.

METHODS: The cohort consisted of 1113 young Danish farmers and rural controls, with a mean age of 19 years at baseline. Sensitisation to birch pollen, grass pollen, cat dander and house dust mite was measured by specific IgE levels in serum samples from baseline and at 15 years' follow-up. Changes in sensitisation were analysed in relation to cumulative endotoxin exposure during follow-up, considering early life farm exposure.

RESULTS: Endotoxin exposure during follow-up was significantly associated with less new onset of specifically grass and birch pollen sensitisation. For the highest versus lowest quartile of cumulative endotoxin exposure, the OR for new-onset IgE sensitisation was 0.35 (0.13-0.91) for birch and 0.14 (0.05-0.50) for grass. On the other hand, loss of pollen sensitisation showed a positive, although mostly non-significant, association with increased levels of endotoxin exposure. Endotoxin exposure was not associated with significant changes in cat dander and house dust mite sensitisation.

CONCLUSIONS: High exposure to endotoxin during young adulthood appears to protect against new onset of pollen sensitisation, independent of childhood farm exposure.

Original languageEnglish
Pages (from-to)139-147
Number of pages9
JournalOccupational and Environmental Medicine
Issue number2
Early online date23 Aug 2017
Publication statusPublished - 15 Jan 2018


  • Adolescent
  • Adult
  • Agricultural Workers' Diseases/etiology
  • Agriculture
  • Allergens/immunology
  • Denmark
  • Endotoxins/immunology
  • Female
  • Humans
  • Hypersensitivity, Immediate/etiology
  • Immunoglobulin E/blood
  • Male
  • Pollen/immunology
  • Young Adult


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