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Original Article
High exposure to endotoxin in farming is associated with less new-onset pollen sensitisation
  1. Grethe Elholm1,
  2. Vivi Schlünssen2,
  3. Gert Doekes3,
  4. Ioannis Basinas1,4,
  5. Anneli Clea Skjelmose Bolund1,
  6. Charlotte Hjort5,
  7. Pernille Milvang Grønager6,
  8. Øyvind Omland7,
  9. Torben Sigsgaard1
  1. 1Department of Public Health, Section for Environment, Occupation and Health, Aarhus University, Danish Ramazzini Center, Aarhus, Denmark
  2. 2National Research Centre for the Working Environment, Copenhagen, Denmark
  3. 3Division of Environmental Epidemiology, Utrecht University, Institute for Risk Assessment Sciences, Utrecht, The Netherlands
  4. 4Centre for Human Exposure Science, Institute of Occupational Medicine, Edinburgh, UK
  5. 5Regional Unit North, Danish Patient Safety Authority, Randers, Denmark
  6. 6Research ALK Abelló, ALK Abelló, Hørsholm, Denmark
  7. 7Aalborg University Hospital, Clinic of Occupational Medicine, Danish Ramazzini Center, Aalborg, Denmark
  1. Correspondence to Dr Grethe Elholm, Department of Public Health, Section for Environment, Occupation and Health, Aarhus University, Bartholins Allé 2, build. 1260, 8000 Aarhus, Denmark; gelh{at}ph.au.dk

Abstract

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.

  • endotoxin
  • farming exposure
  • sIgE
  • allergy
  • pollen sensitisation
  • change in sensitisation
  • farm childhood
  • cohort study

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Footnotes

  • Contributors GE has carried out the analyses and interpretation of the data included in this manuscript. Furthermore, she has drafted the entire manuscript as the first author, and has been responsible for including and amending the manuscript according to the coauthors' suggestions. VS took part in the acquisition and interpretation of data. She also took part in drafting and revising it critically for important intellectual content and final approval of the version to be published. GD contributed to analysis and interpretation of data. He also took part in drafting and revising it critically for important intellectual content and final approval of the version to be published. IB took part in the acquisition and interpretation of the data. He also took part in revising it critically for important intellectual content and final approval of the version to be published. ACSB took part in the acquisition and interpretation of the data. She also took part in revising it critically for important intellectual content and final approval of the version to be published. CH contributed to the conception and design of the study and acquisition of data. She also took part in revising it critically for important intellectual content and final approval of the version to be published. PMG contributed to the acquisition of data. She also took part in revising it critically for important intellectual content and final approval of the version to be published. ØO contributed to the conception and design of the study, and also the acquisition and interpretation of data. He also took part in revising it critically for important intellectual content and final approval of the version to be published. TS contributed to conception and design of the study. He also contributed to the acquisition of data, analysis and interpretation of data. He additionally took part in drafting the article and revising it critically for important intellectual content. Furthermore, he also took part in the final approval of the version to be published.

  • Competing interests None declared.

  • Patient consent Obtained.

  • Ethics approval The Ethical Committees of Region Midtjylland, Denmark.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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