1. US Farm Operators with Asthma:
Respirator Use Among
US Farm Operators with Asthma:
Results from the 2011 Farm and
Ranch Safety Survey
Megan Casey, RN, BSN, MPH
Nurse Epidemiologist
Good Afternoon.
International Society for Agricultural Safety and Health
June 27, 2016
National Institute for Occupational Safety and Health
Respiratory Health Division

2. Work-Related Asthma is caused or exacerbated by work.
Work related asthma is asthma that is caused or exacerbated by exposure to workplace conditions.

3. Work-Related Asthma episodic shortness of breath cough wheeze
chest tightness
Symptoms of work-related asthma include episodic shortness of breath, cough, wheeze and chest tightness.

4. Improves when away from work
Work-Related Asthma
episodic shortness
of breath
cough
wheeze
chest tightness
These symptoms improve when the worker is away from work such as on weekends or vacation.
Improves when away from work

5. Work-Related Asthma
Work-related asthma includes work exacerbated asthma and occupational asthma.

6. Work Exacerbated Asthma (WEA)
Work-Related Asthma
Work Exacerbated Asthma (WEA)
Work exacerbated asthma is CLICK
pre-existing asthma that is worsened by workplace conditions.

7. Work Exacerbated Asthma (WEA)
Work-Related Asthma
Work Exacerbated Asthma (WEA)
pre-existing
pre-existing asthma that is worsened by workplace exposures.

8. Work Exacerbated Asthma (WEA) Occupational Asthma (OA)
Work-Related Asthma
Work Exacerbated Asthma (WEA)
Occupational Asthma (OA)
pre-existing
Occupational asthma is CLICK
new-onset asthma caused by workplace exposures.

9. Work Exacerbated Asthma (WEA) Occupational Asthma (OA)
Work-Related Asthma
Work Exacerbated Asthma (WEA)
Occupational Asthma (OA)
pre-existing
new-onset
new-onset asthma caused by workplace exposures.

10. Work-Related Asthma vs. Non Work-Related Asthma
Individuals with work-related asthma are more likely to experience adverse asthma outcomes than individuals with non-work-related asthma.
Knoeller, et al. 2011

11. asthma attacks These adverse outcomes include asthma attacks
Knoeller, et al. 2011

12. urgent treatment for worsening asthma
asthma attacks
urgent treatment for worsening asthma
urgent treatment for worsening asthma
Knoeller, et al. 2011

13. urgent treatment for worsening asthma
asthma attacks
urgent treatment for worsening asthma
asthma-related emergency room visits
asthma-related emergency room visit
Knoeller, et al. 2011

14. urgent treatment for worsening asthma
asthma attacks
urgent treatment for worsening asthma
asthma-related emergency room visits
very poorly controlled asthma
very poorly controlled asthma
Knoeller, et al. 2011

15. Work-Related Asthma vs. Non Work-Related Asthma
In addition, when compared to non-work-related asthma, individuals with work-related asthma are significantly more likely to have
Knoeller, et al. 2013

16. poor self-rated health
Knoeller, et al. 2013

17. poor self-rated health
impaired physical health
impaired physical health
Knoeller, et al. 2013

18. poor self-rated health
impaired physical health
impaired mental health
impaired mental health
Knoeller, et al. 2013

19. poor self-rated health
impaired physical health
impaired mental health
And activity limitation
activity limitation
Knoeller, et al. 2013

20. 22% of adults with asthma have WEA
Work related asthma is common. An estimated 22% of adults with asthma have work-exacerbated asthma.
Henneberger, et al
Mancuso, et al

21. 15% of adult-onset asthma is related to work
The American Thoracic Society estimates that 15% of adult-onset asthma is related to occupational factors.
Balmes, et al

22. dusts microbial agents diesel exhausts ammonia pesticides other toxins
There are a number of respiratory agents can cause new onset asthma or exacerbate existing asthma in agricultural settings. These agents include: organic and inorganic dusts, microbial agents, diesel exhausts, ammonia, pesticides and other toxins.
other toxins

23. Respirators can reduce respiratory symptoms
But do not provide complete protection
Respirators may be considered to protect workers in agricultural settings. Several systematic reviews of work-related asthma management have found that respirators can reduce respiratory symptoms, but do not provide complete protection.
Nicholson, et al
Beach, et al
Vandenplas, et al

24. Farm and Ranch Safety Survey
To better understand respirator use, asthma and other health & safety issues in agricultural settings, the U.S. Department of Agriculture’s National Agricultural Statistics Service conducted the Farm and Ranch Safety Survey on behalf of NIOSH in 2011.
2011

25. Using data from the 2011 Farm and Ranch Safety Survey, we sought to answer the following questions:

26. What is the prevalence of respirator use among farm operators with asthma?

27. What is the prevalence of respirator use among farm operators with farm work-related asthma?

28. Is respirator use associated with fewer asthma attacks?

29. So we’ll walk through our methods

30. Farm and Ranch Safety Survey
The 2011 Farm and Ranch Safety Survey was a random telephone survey of 25,000 farm operations. Farms were excluded from the survey if they were found to be no-longer active.
2011

31. 11,210 active farm operations were surveyed
From this sample of 25,000 farm operations selected for the survey, a total of 11,210 active farm operations were surveyed.

32. 71%
survey response rate
Excluding farms that were no longer active and other non-contacts, the survey response rate was 71%.

33. 11,210 2.2 million farm operations surveyed estimated farm operations
The National Agricultural Statistics Service then took the results from those 11,210 surveys and weighted them to reflect all 2.2 million farm operations in the United States. Farms were stratified within U.S. Census regions and post-stratified by the value of sales following the sampling methodology.
These methods produced estimates that are nearly identical to the USDA’s Agricultural Census, indicating the validity of this weighting process.
11,210
farm operations surveyed
2.2 million
estimated farm operations

34. Definitions Farm Operator
A Farm Operator was defined as the person who runs the farm and make day-to-day management decisions.
Farm Operator

35. Definitions Current Asthma
Operators were considered to have current asthma if they have ever been told by a doctor, nurse, or other health professional that they had asthma and if they still have asthma.
Current Asthma

36. Definitions Current Farm Work-Related Asthma
Those with current asthma were further asked whether a doctor, nurse, or other health professional ever told them that their asthma was related to their work on the farm. If the answer was “yes,” operators were considered to have farm work-related asthma.
Current Farm
Work-Related Asthma

37. Definitions Respirator Use
Respirator use was assessed by asking if the operators have used a respirator or dust mask on the farm or ranch in the past 12 months.
Respirator Use

38. Statistical Analysis SAS 9.3
For our statistical analyses, we used SAS software version 9.3 using methods that account for complex survey design.
SAS 9.3

39. Statistical Analysis Chi-square Test
The Rao-Scott chi-square test of independence was used to test the differences in bivariate proportions.
Chi-square Test

40. Statistical Analysis Logistic Regression
Variables associated with respirator use with p less than .25, were included in a multivariate logistic regression model.
Logistic Regression

41. Prevalence Odds Ratios
Statistical Analysis
Prevalence Odds Ratios were adjusted for age, sex, region, farm type and value of sales.
Prevalence Odds Ratios

42. Demographic characteristics of farm operators and farm operators with asthma had been previously described by Mazurek, et al, but I will briefly touch on them here:
Results

43. 84%
male
Of the estimated 2.2 million primary farm operators in 2011, 84% were male
Mazurek, et al. 2015

44. 95% over the age of 40 95% were over the age of 40
Mazurek, et al. 2015

45. 60%
non-smokers
And 60% were non-smokers
Mazurek, et al. 2015

46. current asthma that was5%
farm operators had
current asthma
15%
current asthma that was
work-related
An estimated 5% of farm operators had current asthma in 2011, and among those, an estimated 15% were told by a clinician that their asthma was related to their work on the farm.
Mazurek, et al. 2015

47. 36% used a respirator or dust mask in the past 12 months
We found that an estimated 36% of farm operators reported to have used a respirator or dust mask in the past 12 months.

48. Respirator or Dust Mask Users
younger age
married
Operators that wore respirators or dust masks were significantly more likely to be younger, married and manage farms that had a higher value of sales.
higher farm value of sales

49. Respirator or Dust Mask Users
manure storage facilities
grain production
In addition, operators who wore respirators or dust masks were more likely to manage farms with manure storage facilities, are involved in grain production or apply pesticides.
pesticides

50. Operators with current asthma were significantly more likely to use a respirator or dust mask*
47%
35%
Here we compare the proportion of farm operators who used respirators or dust masks in the past 12 months among those with current asthma and those with no asthma. Among operators with current asthma, 47% reported respirator or dust mask use. And among those with no diagnosis of asthma, 35% reported respirator or dust mask use.
Compared with farm operators with no asthma, those with current asthma were more likely to use a respirator or dust mask in the previous 12 months and this difference was statistically significant.
*p ≤ .05 using Rao-Scott chi-square to test for differences in the distribution of proportions

51. Operators with farm work-related asthma were significantly more likely to use a respirator or dust mask*
61%
44%
Here we compare the proportion of farm operators who used respirators or dust masks in the past 12 months among those with current farm work-related asthma and those with current asthma that is not farm-work related.
Among operators with farm work-related asthma, 61% reported respirator or dust mask use. And among those with asthma that is not farm work related, 44% reported respirator or dust mask use.
Compared with farm operators with current asthma that is not farm work-related, those with farm work-related asthma were more likely to use a respirator or dust mask in the previous 12 months and this difference was statistically significant.
*p ≤ .05 using Rao-Scott chi-square to test for differences in the distribution of proportions

52. No significant difference in respirator/dust mask use for those current asthma and whether they reported asthma attack
50%
44%
Here we compare the proportion of farm operators who used respirators or dust masks in the past 12 months and whether they’ve had an asthma attack in the past 12 months.
Among operators reporting an asthma attack, 50% reported respirator or dust mask use. And among those reporting no asthma attack in the past 12 months, 44% reported respirator or dust mask use.
We found no significant difference in respirator or dust mask use was found for farm operators with current asthma who reported an asthma attack in the past 12 months and those that did not (p=.27)

53. No significant difference in respirator/dust mask use for those current asthma and whether they reported asthma attack at work
58%
45%
Here we compare the proportion of farm operators who used respirators in the past 12 months and whether they’ve had an asthma attack at work.
Among operators reporting an asthma attack at work, 58% reported respirator or dust mask use. And among those reporting an asthma attack that was not at work, 45% reported respirator or dust mask use.
We found no significant difference in respirator or dust mask use for farm operators with current asthma who reported an asthma attack at work and those that reported an asthma attack while not at work.

54. Operators with farm work-related asthma who had an asthma attack at work
11x
more likely to report
respirator/dust mask use
After adjustment for age, sex, region, farm type and value of sales, we found that operators with farm work-related asthma who had an asthma attack at work were 11 times more likely to report respirator or dust mask use than those who did not have an asthma attack at work.

55. Operators with farm work-related asthma with pesticide exposure in the past 12 months
more likely to report
respirator/dust mask use
And operators with farm work-related asthma and pesticide exposure were 8 times more likely to report respirator use than those who did not have pesticide exposure.

56. To summarize, we found
Conclusions

57. A higher proportion of respirator/dust mask use among operators
with current asthma
Farm operators with current asthma were more likely to use a respirator in the previous 12 months compared to those with no asthma

58. A higher proportion of respirator/dust
mask use among operators with farm
work-related asthma
In addition, we found that operators with current farm work-related asthma were more likely to use a respirator in the previous 12 months compared to those with current asthma that is not farm work-related.

59. More respirator/dust mask use among
operators with farm work-related asthma
who had an asthma attack at work
Finally, we found that farm operators with farm work-related asthma who had an asthma attack at work used respirators more than those who had an asthma attack that was not at work.

60. Limitations
There are a number of limitations to this study

61. Cross-sectional Design Limitations
Due to the cross-sectional design, we were not able to determine if respirators were ineffective at preventing asthma attacks at work or if farm operators chose to wear a respirator as a result of having an asthma attack at work. Thus, the timing and causality between respirator use and asthma attacks cannot be determined.

62. Limitations Proxy Respondents
The data for the 2011 Farm and Ranch Safety Survey were self-reported either by the farm operator or their spouse. The information collected from the spouse may not accurately reflect the experience of the farm operator. There was no indicator variable available to us that specified whether the respondent was the farm operator or spouse.

63. Respirator Use Definition Limitations
Respirator use was not specifically defined in the survey, so responses to respirator use questions may reflect issues of adherence, regulations and various respirator types. In addition, both terms, respirator and dust mask, were used during the telephone interview, as many respondents confused N-95 respirators with dust masks during cognitive testing. So we cannot specify which type of respiratory protection was used in the past 12 months.

64. Healthy Worker Survivor Effect Limitations
This survey was administered to farm operators working on active farm operations and may be subject to healthy worker bias; operators with severe asthma may have left the workforce. Thus, the results may be underestimating the population asthma prevalence.

65. Farm operators with asthma should be:
Educated on respirator use
Evaluated for respirator tolerance
We recommend that farm operators with asthma should be educated on respirator use and evaluated for respirator tolerance as part of their asthma management plan. Periodic assessment of asthma symptoms and lung function testing can help the clinician assess respirator efficacy, and determine specific exposures that increase risk for adverse health effects.

66. 1 in 7 asthma patients talk to their clinicians about work-relatedness
However, NIOSH research has shown that only one in seven employed adults with asthma talk to their clinician about the possible role of work in their disease. Occupational risk factors should be considered during assessments of patients with asthma-like symptoms and those with existing asthma.
Mazurek, et al. 2012

67. Acknowledgements NIOSH Respiratory Health Division
NIOSH National Personal Protective Technology Laboratory
Jacek Mazurek
Kerri Wizner
Christopher Coffey
NIOSH Division of Safety Research
Kitty Hendricks
Larry Layne
Michael Goldcamp
NIOSH Office of the Director
Brad Husberg
And I would like to acknowledge my NIOSH colleagues for their help with this project.
National Institute for Occupational Safety and Health
Respiratory Health Division

68. Thank you Megan Casey, RN, BSN, MPH Nurse Epidemiologist
LT, United States Public Health Service
NIOSH Respiratory Health Division
Surveillance Branch
Phone:
For more information please contact the National Institute for Occupational Safety and Health (NIOSH), Respiratory Health Division
1095 Willowdale Road, Morgantown, WV
Telephone:
Visit:
The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention.
National Institute for Occupational Safety and Health
Respiratory Health Division