Chronic bronchitis among nonsmoking farm women in the agricultural health study

Our plain-English summary of Chronic bronchitis among nonsmoking farm women in the agricultural health study, by M. Valcin, P.K. Henneberger, G.J. Kullman, et al (Journal of Occupational and Environmental Medicine, 2007).

The study

• Authors: M. Valcin, P.K. Henneberger, G.J. Kullman, D.M. Umbach, S.J. London, M.C. Alavanja, D.P. Sandler, J.A. Hoppin
• Journal: Journal of Occupational and Environmental Medicine
• Published: 2007;49(5):574-83
• Cited by: 58 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Objective: The purpose of this study was to examine agricultural risk factors for chronic bronchitis among nonsmoking farm women.

Methods: We used self-reported enrollment data from the 21,541 nonsmoking women in the Agricultural Health Study to evaluate occupational risk factors for prevalent chronic bronchitis among farm women. Odds ratios (ORs) for chronic bronchitis for occupational exposures were adjusted for age, state, and related agricultural exposures.

Results: Applying manure and driving combines were independently associated with chronic bronchitis. Off-farm job exposures associated with chronic bronchitis were organic dusts, asbestos, gasoline, and solvents. Five pesticides were associated with chronic bronchitis after multivariate adjustment and sensitivity analyses: dichlorvos (OR=1.63, 95% CI=1.01, 2.61), DDT (OR=1.67, 95% CI=1.13, 2.47), cyanazine (OR=1.88, 95% CI=1.00, 3.54), paraquat (OR=1.91, 95% CI=1.02, 3.55), and methyl bromide (OR=1.82, 95% CI=1.02, 3.24).

Conclusion: Pesticides as well as grain and dust exposures were associated with chronic bronchitis among nonsmoking farm women.

In plain English

This cross-sectional study used questionnaires from the Agricultural Health Study, which enrolled licensed pesticide applicators in Iowa and North Carolina, and their spouses, between 1993 and 1997. It analysed 21,541 female spouses aged 20 or older who reported having smoked fewer than 100 cigarettes in their lifetime. Of these, 583 (2.7%) reported that a doctor had diagnosed chronic bronchitis after age 20. Applying manure (odds ratio 1.58, 95% CI 1.18 to 2.12) and driving combines (odds ratio 1.57, 95% CI 1.18 to 2.10) were associated with chronic bronchitis. Among women who had held an off-farm job, self-reported asbestos exposure in their longest-held such job was associated with chronic bronchitis (odds ratio 1.56, 95% CI 1.11 to 2.20). No fiber type was given. Off-farm gasoline and solvent exposures were also associated. Use of any pesticide was not associated, but five specific pesticides were, including DDT and paraquat. The authors concluded that pesticides as well as grain and dust exposures were associated with chronic bronchitis. They noted that diagnoses were self-reported, with no symptom data.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Cross-sectional analysis of enrollment questionnaire data from a prospective cohort (the Agricultural Health Study)
• Who was studied: 21,541 female spouses of licensed private pesticide applicators in Iowa and North Carolina, enrolled 1993 to 1997. All were at least 20 years old and reported not having smoked 100 cigarettes in their lifetime. Of these, 583 reported doctor-diagnosed chronic bronchitis and 20,958 served as controls
• Exposure: Self-reported current farm activities, lifetime pesticide use, and ever-exposure to 19 hazards in the longest-held off-farm job. The 19 hazards included asbestos, listed among inorganic dusts with mineral and sand dust. No asbestos fiber type or dose was given
• Main results:
  • 583 of 21,541 nonsmoking farm women (2.7%) reported doctor-diagnosed chronic bronchitis after age 20
  • Applying manure as fertilizer was associated with chronic bronchitis (OR 1.58, 95% CI 1.18, 2.12), adjusted for age, state and other crop activities
  • Driving combines was associated with chronic bronchitis (OR 1.57, 95% CI 1.18, 2.10), adjusted for other farm equipment
  • Among women with an off-farm job (515 cases, 18,305 controls), asbestos exposure was reported by 8% of cases and 5% of controls. The OR was 1.59 (95% CI 1.13, 2.22) adjusted for age and state, and 1.56 (95% CI 1.11, 2.20) when also adjusted for mineral/mining and silica/sand dust
  • Off-farm gasoline (OR 1.88, 95% CI 1.23, 2.88) and solvents (OR 1.58, 95% CI 1.18, 2.10) were associated with chronic bronchitis
  • Overall pesticide use was not associated with chronic bronchitis (OR 1.14, 95% CI 0.97, 1.35)
  • Women who applied pesticides 120 days or more in their lifetimes had increased odds of chronic bronchitis (OR 1.50, 95% CI 1.17, 1.91)
  • DDT remained associated after adjustment for other organochlorines (OR 1.67, 95% CI 1.13, 2.47)
  • Dichlorvos remained associated after adjustment for other organophosphates (OR 1.63, 95% CI 1.01, 2.61)
  • Cyanazine, adjusted for other herbicides: OR 1.88 (95% CI 1.00, 3.54)
  • Paraquat, adjusted for other herbicides: OR 1.91 (95% CI 1.02, 3.55)
  • Methyl bromide, the only fumigant with at least five cases, was associated with chronic bronchitis (OR 1.82, 95% CI 1.02, 3.24)
  • When women reporting asthma were excluded, most associations remained, with some attenuation. The associations for carbofuran, parathion and petroleum oil disappeared. The article does not report the asbestos result in this sensitivity analysis
• The authors' conclusion: The authors concluded that pesticides as well as grain and dust exposures were associated with chronic bronchitis among nonsmoking farm women
• Limitations the authors state:
  • Chronic bronchitis was based on self-reported doctor diagnosis, with no symptom data, which may have caused misclassification
  • Current farm activities were used as surrogates for past activities, but chronic bronchitis may lead women to change their farming habits
  • There were no data on frequency of use of specific pesticides
  • The data could not separate effects of pesticide application from those of correlated farm activities

Topics

Medical terms in this study, explained in our Lexicon: Odds Ratio, Occupational Exposure.

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