House Dust Endotoxin Levels Are Associated with Adult Asthma in a U.S. Farming Population

Details

• Personal Author:
  Barker-Cummings C ; Carnes MU ; Freeman LEB ; Hankinson, John L. ; Henneberger, Paul K. ; Hoppin JA ; London SJ ; Long S ; Metwali N ; O'Connell EL ; Richards M ; Sandler DP ; Thorne PS ; Umbach DM ; Wyss AB
• Description:
  Rationale: Endotoxin initiates a proinflammatory response from the innate immune system. Studies in children suggest that endotoxin exposure from house dustmay be an important risk factor for asthma, but few studies have been conducted in adult populations. Objectives: To investigate the association of house dust endotoxin levels with asthma and related phenotypes (wheeze, atopy, and pulmonary function) in a large U.S. farming population. Methods: Dust was collected from the bedrooms (n = 2,485) of participants enrolled in a case-control study of current asthma (927 cases) nested within the Agricultural Health Study. Dust endotoxin was measured by Limulus amebocyte lysate assay. Outcomes were measured by questionnaire, spirometry, and blood draw. We evaluated associations using linear and logistic regression. Measurements and Main Results: Endotoxin was significantly associated with current asthma (odds ratio [OR], 1.30; 95% confidence interval [CI], 1.14-1.47), and this relationship was modified by early-life farm exposure (born on a farm: OR, 1.18; 95% CI, 1.02-1.37; not born on a farm: OR, 1.67; 95% CI, 1.26-2.20; Interaction P = 0.05). Significant positive associations were seen with both atopic and nonatopic asthma. Endotoxin was not related to either atopy or wheeze. Higher endotoxin was related to lower FEV1/FVC in asthma cases only (Interaction P = 0.01). For asthma, there was suggestive evidence of a gene-byenvironment interaction for the CD14 variant rs2569190 (Interaction P = 0.16) but not for the TLR4 variants rs4986790 and rs4986791. Conclusions: House dust endotoxin was associated with current atopic and nonatopic asthma in a U.S. farming population. The degree of the association with asthma depended on early-life farm exposures. Furthermore, endotoxin was associated with lower pulmonary function in patients with asthma. [Description provided by NIOSH]
• Subjects:
  Agriculture Asthma Dust Endotoxins Environmental Exposure Farmers Lung Occupational Health Respiratory System Respiratory Tract Diseases Safety Workplace

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• Keywords:
  Agricultural Industry Agricultural Workers Author Keywords: Atopy Bacteria Bronchial Asthma CD14 Cell Biology Cell Function Cellular Function Children Dust Exposure Dusts Environmental Exposure Farm Workers Genetic Factors Lung Function Molecular Biology Pulmonary Function Statistical Analysis TLR4 Wheeze Work Environment Workers

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• ISSN:
  2329-6933
• Document Type:
  Text
• Genre:
  Journal Article
• Place as Subject:
  Georgia ; Iowa ; Maryland ; North Carolina ; OSHA Region 3 ; OSHA Region 4 ; OSHA Region 7 ; West Virginia
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  RHD - Respiratory Health Division
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  324-331
• Volume:
  14
• Issue:
  3
• NIOSHTIC Number:
  nn:20049529
• Citation:
  Ann Am Thorac Soc 2017 Mar; 14(3):324-331
• Contact Point Address:
  Stephanie J. London, M.D., Dr.P.H., National Institute of Environmental Health Sciences, P.O. Box 12233, Mail Drop A3-05, Research Triangle Park, NC 27709
• Email:
  london2@niehs.nih.gov
• Federal Fiscal Year:
  2017
• Peer Reviewed:
  True
• Source Full Name:
  Annals of the American Thoracic Society
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:717ec00ca62b9d6766fd62e11da1e8728162ab3d0589a58201f133019a9e5997bbc61c81a9fb71599b6a59d2af39d487f55a856b931e079bc1239b3deff5f93d
• Download URL:
  https://stacks.cdc.gov/view/cdc/210282/cdc_210282_DS1.pdf
• File Type:
  [PDF - 567.05 KB ]