title: Respiratory disease in United States farmers.
abstract: OBJECTIVE
  Farmers may be at increased risk for adverse respiratory outcomes compared with the general population due to their regular exposures to dusts, animals and chemicals. However, early life farm exposures to microbial agents may result in reduced risk. Understanding respiratory disease risk among farmers and identifying differences between farmers and other populations may lead to better understanding of the contribution of environmental exposures to respiratory disease risk in the general population.
  
  
  METHODS
  We compared the prevalence of self-reported respiratory outcomes in 43548 participants from the Agricultural Health Study (AHS), a prospective cohort of farmers and their spouses from Iowa and North Carolina, with data from adult participants in the National Health and Nutrition Examination Survey (NHANES) over the same period (2005-2010).
  
  
  RESULTS
  AHS participants had lower prevalences of respiratory diseases (asthma, adult-onset asthma, chronic bronchitis and emphysema), but higher prevalences of current respiratory symptoms (wheeze, cough and phlegm) even after controlling for smoking, body mass index and population characteristics. The overall prevalence of asthma in the AHS (7.2%, 95% CI 6.9 to 7.4) was 52% of that in NHANES (13.8%, 95% CI 13.3 to 14.3), although the prevalence of adult-onset asthma among men did not differ (3.6% for AHS, 3.7% for NHANES). Conversely, many respiratory symptoms were more common in the AHS than NHANES, particularly among men.
  
  
  CONCLUSIONS
  These findings suggest that farmers and their spouses have lower risk for adult-onset respiratory diseases compared with the general population, and potentially higher respiratory irritation as evidenced by increased respiratory symptoms.
authors.affiliation: Epidemiology Branch, National Institute of Environmental Health Sciences, NIH/DHHS, Research Triangle Park, North Carolina, USA Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, USA.
authors.forename: Jane A
authors.initials: JA
authors.lastname: Hoppin
authors.affiliation: Biostatistics Branch, National Institute of Environmental Health Sciences, NIH/DHHS, Research Triangle Park, North Carolina, USA.
authors.forename: David M
authors.initials: DM
authors.lastname: Umbach
authors.affiliation: Westat, Durham, North Carolina, USA.
authors.forename: Stuart
authors.initials: S
authors.lastname: Long
authors.affiliation: Department of Epidemiology, UNC Chapel Hill, Chapel Hill, North Carolina, USA.
authors.forename: Jessica L
authors.initials: JL
authors.lastname: Rinsky
authors.affiliation: Division of Respiratory Disease Studies, NIOSH, CDC, DHHS, Morgantown, West Virginia, USA.
authors.forename: Paul K
authors.initials: PK
authors.lastname: Henneberger
authors.affiliation: Laboratory of Respiratory Biology, National Institute of Environmental Health Sciences, NIH/DHHS, Research Triangle Park, North Carolina, USA.
authors.forename: Paivi M
authors.initials: PM
authors.lastname: Salo
authors.affiliation: Laboratory of Respiratory Biology, National Institute of Environmental Health Sciences, NIH/DHHS, Research Triangle Park, North Carolina, USA.
authors.forename: Darryl C
authors.initials: DC
authors.lastname: Zeldin
authors.affiliation: Epidemiology Branch, National Institute of Environmental Health Sciences, NIH/DHHS, Research Triangle Park, North Carolina, USA.
authors.forename: Stephanie J
authors.initials: SJ
authors.lastname: London
authors.affiliation: Occupational and Environmental Epidemiology Branch, National Cancer Institute, NIH/DHHS, Rockville, Maryland, USA.
authors.forename: Michael C R
authors.initials: MC
authors.lastname: Alavanja
authors.affiliation: Occupational and Environmental Epidemiology Branch, National Cancer Institute, NIH/DHHS, Rockville, Maryland, USA.
authors.forename: Aaron
authors.initials: A
authors.lastname: Blair
authors.affiliation: Occupational and Environmental Epidemiology Branch, National Cancer Institute, NIH/DHHS, Rockville, Maryland, USA.
authors.forename: Laura E
authors.initials: LE
authors.lastname: Beane Freeman
authors.affiliation: Epidemiology Branch, National Institute of Environmental Health Sciences, NIH/DHHS, Research Triangle Park, North Carolina, USA.
authors.forename: Dale P
authors.initials: DP
authors.lastname: Sandler
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000383:Agriculture; D000393:Air Pollutants / Q000009:adverse effects*; D001249:Asthma / Q000453:epidemiology / Q000209:etiology; D003371:Cough / Q000453:epidemiology / Q000209:etiology*; D005260:Female; D006801:Humans; D007484:Iowa / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009093:Mucus / Q000378:metabolism; D009657:North Carolina / Q000453:epidemiology; D009749:Nutrition Surveys; D009784:Occupational Diseases / Q000453:epidemiology / Q000209:etiology*; D016273:Occupational Exposure / Q000009:adverse effects*; D015995:Prevalence; D011446:Prospective Studies; D012120:Respiration Disorders / Q000453:epidemiology / Q000209:etiology*; D012135:Respiratory Sounds / Q000209:etiology*; D012307:Risk Factors; D012737:Sex Factors; D018454:Spouses; D055815:Young Adult
chemical_list: D000393:Air Pollutants