The Healthy Dairy Worker Study: A Longitudinal Cohort Study of Dairy Workers’ Respiratory Health

Abstract

Background: Studies have reported that Agricultural workers have elevated rates of respiratory health issues; however, the literature on respiratory function in dairy workers is limited and contradictory. Dairy work involves more exposure to dust and gases when compared to other occupations. Dairy workers work in a variety of settings, including increasingly larger and more industrialized farms that involve exposure to multiple biological and chemical substances. Previous studies of dairy workers have reported that dairy work is associated with acute airway obstruction, yet others have reported lower rates of asthma compared to other occupational groups. This thesis presents preliminary data from a study of dairy workers in Washington State. Objective: Compare and assess pulmonary function among dairy workers and community controls. Methods: Respiratory function was assessed in 40 dairy workers and 22 community controls over a 6-month period. Subjects were asked to complete a questionnaire, spirometry and exhaled nitric oxide at baseline, three, and six months. Descriptive statistics were used to describe both dependent and independent variables. Linear Mixed Models were used to compare exhaled nitric oxide, FEV1, FVC, and the FEV1/FVC Ratio between cases and controls. Results: The dairy workers had a significantly (5.93%) higher FEV1/FVC ratio than the community controls (p=0.009). Within the dairy workers, those who had greater contact with animals had slightly better FEV1/FVC ratio (0.33% for contact with cows, 1.31% for contact with calves) compared to the dairy workers with minimal to no contact with animals. CONCLUSION: The spirometry FEV1/FVC ratio for dairy workers can suggest that dairy workers may have better airway function compared to community members.