Acute restrictive effect associated with working on large California dairies.
Eastman-C; Mitchell-DC; Tancredi-DJ; Bennett-DH; Mitloehner-FM; Schenker-MB
Am J Respir Crit Care Med 2011 May; 183:(Meeting Abstracts):A4771
RATIONALE: Dairy work has been associated with decreased lung function in Europe and the Midwestern and Eastern US. However, California dairies are unique in being open-air and having substantially larger herd sizes. The purpose of our study is to characterize the occupational exposure of California dairy workers and determine if workplace exposures pose a respiratory health risk. METHODS: We hypothesize that dairy work on large California dairies is associated with lower baseline lung function as well as an acute decline in lung function over the work shift. This cross-sectional study of 210 male dairy workers and 47 male control (vegetable processing plant) employees conducted in the summer of 2008 included questionnaires and spirometry pre- and post-work shift. Mixed effects models were used to assess the association between dairy work and lung function values. RESULTS: The average age was 34 (SD=11.0) and 35 years (SD=12.2) for dairy and control participants, respectively. Most were of Mexican or Central American origin, with 94% of dairy and 98% of control workers self-identifying as Hispanic. 27% of dairy workers and 13% of control facility employees were current smokers (p<0.05), with an average of 4.7 (SD=4.4) and 3.6 (SD=5.1) cigarettes per day for dairy and control workers, respectively. Baseline lung function values were generally lower among dairy workers, but the results were only marginally significant for FEV6 (p=0.08). There was no significant association of dairy work with other standard measures of lung flow or volume. Dairy workers experienced a significantly greater cross-shift decrement in FEV1, FEV6, and FVC compared to control workers after adjusting for smoking status, but cross-shift decline was not associated with FEF25-75%, FEV1/FEV6 or FEV1/FVC (Table 1). CONCLUSION: The significant dairy vs. control worker adjusted difference in mean cross-shift declines in FEV1 (p<0.05) suggests a possible association of exposure with airway obstruction, but this is not supported by the results for FEF25-75%, FEV1/FVC or FEV1/FEV6. Significant cross-shift decrement in FEV6 and FVC (p<0.01) suggests an acute restrictive effect among dairy workers. Since baseline values are only marginally associated with dairy work, this appears to be a reversible restrictive effect. Future analyses will include examining tasks around a dairy to see if any specific job or exposure is associated with lung function decrement.
Dairy-products; Agriculture; Agricultural-industry; Agricultural-products; Agricultural-workers; Respiratory-system-disorders; Pulmonary-system-disorders; Lung-disorders; Lung-function; Animals; Risk-analysis; Work-intervals; Spirometry; Pulmonary-function-tests; Humans; Men; Health-surveys; Questionnaires; Racial-factors; Smoking; Airway-obstruction; Vital-capacity
C. Eastman, University of California, Davis, Davis, CA
American Journal of Respiratory and Critical Care Medicine
University of California - Davis