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

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

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.

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

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

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.

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

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.

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.

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

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

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

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

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

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

poor self-rated health Knoeller, et al. 2013

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

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

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

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. 2011. Mancuso, et al. 2003.

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. 2003.

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

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. 2005. Beach, et al. 2005. Vandenplas, et al. 2012.

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

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

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

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

Is respirator use associated with fewer asthma attacks?

So we’ll walk through our methods

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

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.

71% survey response rate Excluding farms that were no longer active and other non-contacts, the survey response rate was 71%.

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

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

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

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

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

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

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

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

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

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

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

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

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

current asthma that was 5% 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

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.

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

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

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

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

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)

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.

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.

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.

To summarize, we found Conclusions

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

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.

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.

Limitations There are a number of limitations to this study

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.

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.

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.

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.

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.

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

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

Thank you Megan Casey, RN, BSN, MPH Nurse Epidemiologist LT, United States Public Health Service NIOSH Respiratory Health Division Surveillance Branch Phone: 304-285-6078 Email: ydg7@cdc.gov For more information please contact the National Institute for Occupational Safety and Health (NIOSH), Respiratory Health Division 1095 Willowdale Road, Morgantown, WV 26505 Telephone: 304-285-6284 Visit: http://www.cdc.gov/niosh/contact/im-drds.html 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