Background: The prevalence of chronic cough, chronic phlegm, dyspnea, and non-cold wheeze was estimated from a mixed-mode survey of Ohio cash grain farmers in 1993.
Methods: Personal characteristics of the principal operators (POs) such as age and cigarette smoking, in addition to selected farm characteristics and relevant medical and work history factors potentially associated with both exposure to respiratory irritants and subsequent respiratory symptoms were considered.
Results: The overall design-adjusted prevalences (and the corresponding 95% confidence intervals (CIs) were: 9.4% (7.6-11.1%) for chronic cough, 10.8% (9.0-12.6%) for chronic phlegm, 16.2% (14.1-18.3%) for dyspnea, and 8.1% (6.4-9.8%) for non-cold wheeze. In univariate and multivariate analyses, smoking status was found, not surprisingly, to be the strongest predictor of increased symptom prevalence compared to all other factors. Other non-occupational factors found associated with increased symptom prevalence include age (cough, phlegm, dyspnea) and pet allergy (non-cold wheeze). Occupational factors found at least weakly associated with increased symptom prevalence include lifetime hours of cab tractor operation (cough); percent time spent farming (phlegm); having livestock other than cattle, cows, and calves (dyspnea); acres of corn for silage or green chop (cough); acres of alfalfa hay (non-cold wheeze); and personal involvement with pesticides (cough).
Conclusions: Symptom prevalences reported here are consistent with previous findings from studies of other groups of farmers. Results pertaining to factors found associated with symptom prevalences should be interpreted in light of several sources of potential bias.