Presented by: Chelsea Eastman COEMH Training Workshop May 2010

1. Respiratory symptoms of workers on large dairies in the San Joaquin Valley compared to control facility employees Presented by: Chelsea Eastman COEMH Training Workshop May 2010

2. Background: CA Dairy Industry • $7.3 billion, milk & cream sales • 21.9% US milk supply • CA: 1,960 dairies • 1.8 million lactating cows • Northern CA: 1,788 dairies • 1.7 million lactating cows • Average herd size: 952 Source: California Department of Food & Agriculture, 2008

3. Background: Dairy Operations

4. Background: Dairy Workers • CA dairy employees: 16,700 • 8% of agricultural workers • SJV dairy employees: 12,700 • 15% of agricultural workers Source: CDFA, 2005

5. Background: Agricultural Work & Respiratory Health • Chronic endotoxin exposure • chronic bronchitis • reduced lung function • PM exposure • reduced lung function • airway inflammation Sources: Iversen et al, 1994; Omland, 2002; Reynolds et al, 1996

6. Background: Agricultural Work & Respiratory Health • Dairy farmers at high risk • respiratory health problems • decreased lung function • Animal confinement facilities • airway inflammation • organic dust toxic syndrome Sources: Kawada et al, 2008; Chaudemanche et al, 2003; Dalphin et al, 1998; Gainet et al, 2007; Heller et al, 1986; Malmberg, 1990; Venier et al, 2006

7. Study Design and Methods • Cross-sectional • June through September 2008 • Dairy selection • ≥ 1,000 milking cows • Randomly selected • ≤ 3 per county • Inclusion criteria • 18 - 65 years • Male • Able to work a fully monitored 6-hr shift • Able to perform spirometry • Work around cows

8. Study Design and Methods • Control facility • Vegetable processing plant • Selection criteria • Similar worker demographics as dairies • Night shift • Inclusion criteria • 18 – 65 years • Male • Able to work a fully monitored 6-hr shift • Able to perform spirometry • No work around cows • No respiratory exposures (i.e. cleaning chemicals)

9. Study Design and Methods • 13 dairies • 226 participants • 90% participation • Control: 1 vegetable processing plant • 49 participants • 90% participation

10. Study Design and Methods • Pre-shift interview • Demographics • Asthma & atopy • Chronic respiratory conditions • Post-shift interview • Time-activity log • Smoking/tobacco use • Health self-assessment

11. Hypothesis Dairy workers exhibit a higher prevalence of respiratory symptoms than a comparison group of workers independent of age, cigarette smoking, and non-occupational effect modifiers.

12. Results: Study Population *p-value < 0.05

13. Results: Study Population † p-value < 0.0001

14. Results: Study Population

15. Results: Chronic respiratory conditions Current/former smokers Never smokers *p < 0.05

16. Results: Acute respiratory symptoms Current smokers Former/never smokers *p < 0.05

17. Key Points & Future Activities • Dairy workers have a significantly higher prevalence of asthma symptoms than controls • First project to study dairy workers in the Western United States • Document if intervention is warranted • Disseminate results to dairy community • Design and target interventions to protect dairy worker respiratory health

18. Dr. Marc Schenker Dr. Frank Mitloehner Dr. Debbie Bennett Dr. Diane Mitchell Cal-DEHRI Group WCAHS Acknowledgments

19. THANK YOU