A total of 122 participants were enrolled and completed respiratory health questionnaires administered during three rounds of data collection during the summer of 2008. Dates of data collection were categorized into three approximately month-long time intervals: (1) June 13-July 11 (n=122), (2) July 12-August 10 (n=117), and (3) August 11-September 9 (n=114). Three participants were lost to follow-up before July 12^th and five others were lost before August 11^th. The final study population in this analysis is the 122 farmworkers who participated in the first round of data collection in 2008.

Questionnaires were administered by Spanish-speaking study personnel who traveled to the farmworkers’ residences for each round of data collection. Demographic and other characteristics of the population were collected in the first questionnaire administered. In the occupational exposure assessment portion of all three questionnaires, participants responded to questions about whether they worked on each of the last three days, including today, and then indicated how many hours they spent performing selected activities (e.g., planting, applying pesticide, harvesting) on each of the last three days. Respondents who indicated that they performed the activities one or more hours on any of the last three days were classified as having performed the specific activity.

Respiratory and allergic symptoms were identified using symptom-related questions based on items from the European Community Respiratory Health Survey questionnaire.¹⁴ In all three rounds of data collection, respondents were also asked whether they had wheezing or difficulty breathing, itchy eyes, nasal allergies, or runny nose in the last three days. In the initial questionnaire, respondents were asked whether they ever experienced wheezing symptoms and whether they had wheezing, been awoken by shortness of breath, or had nasal allergies in the last 12 months. In the next two questionnaires, these items referred to the last month, referencing the month since the previous data collection.

Table I also presents the prevalence of eye and nasal symptoms in this population. Across the agricultural season, the prevalences of nasal allergies and runny or stuffy nose symptoms both notably declined after the first data collection of the season. When wheezing, waking due to cough, and waking due to shortness of breath were combined, the prevalence of any of these self-reported respiratory symptoms declined from 21% (n=25) to 10% (n=11).

In the first of the three questionnaires, nearly 24% of the participants reported ever wheezing, 16% reported wheezing in the last year, 8% in the last month, and 3% in the last three days. Little data exist with which to compare our results. Among a population of adult Hispanic migrant farmworkers in Indiana, 6.2% reported chronic wheeze;¹⁸ in a sample of Hispanic farmworkers in California, 2.8% reported persistent wheeze.¹⁹ In our sample, the prevalence of wheeze in the last year was similar to that of adults in the US (16.5%), using data from the National Health and Nutrition Examination Survey (NHANES) 2005–2006.²⁰ The decreasing prevalence of wheezing in the past month could be due to changes in allergens or other exposures that trigger wheezing or to changes in work- or non work-related behaviors, including occupational activities, the use of personal protective equipment, smoking habits, exercise or other aspects of one’s behavior that affect respiratory health.

We conducted these analyses to describe the respiratory health status of a population of Latino farmworkers and to investigate the associations between farmworking activities and symptoms. We are unable to draw conclusions about the prevalence of diagnosed respiratory disease and instead provide estimates of the prevalence of several hallmark symptoms. Clinical assessment of respiratory disease or additional information about access to diagnostic healthcare services would improve our ability to attribute the reported symptoms to asthma, assess asthma severity, and investigate associations between the specific farmworking activities and mild to severe asthma. We were also unable to assess the roles of ambient air quality, pre-existing health status, co-morbid conditions, and other factors with important contributions to respiratory health; accounting for these as well as for multiple farmworking exposures would strengthen future research about respiratory health of farmworkers. In particular, detailed information about the frequency and safety precautions with which farmworkers apply, handle, transport, or otherwise come into direct contact with pesticides and how much time passes between the application of pesticides onto the crops and farmworkers’ re-entry into the fields would provide valuable information about the frequency and intensity of the pesticide exposures and the onset of new respiratory symptoms or exacerbation of existing symptoms. Using these data, we were not able to estimate the extent to which the healthy worker effect affected our study population and our results. Workers must be physically fit to be hired into farm labor jobs, and they must continue to be strong and healthy to continue without injuries or illnesses that would prevent them from continuing to work throughout the agricultural season. In this study, 8 of the 122 participants were lost to follow-up between the first and final interviews and each of the 8 responded negatively to the respiratory and allergy symptom questions included in the initial questionnaire. We are unable to determine whether pre-existing respiratory health status affected individuals’ decisions to enroll or continue to participate in our study. We also have no information about whether farmworkers who reported respiratory symptoms made any changes to their routines or work activities to reduce their inhalation exposures; such information would be a useful addition to future research about inhalation exposures and respiratory health in a larger cohort of farmworkers.