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Hearing Loss, Noise Exposures, and
Hearing Protection Use in Midwestern
Farmers: A Preliminary analysis
Josie J. Ehlers, MPH
Environmental, Agricultural, and Occupational Health Dept.
College of Public Health, University of Nebraska Medical Center
June 27, 2016
Hazardous noise in agriculture
• High prevalence of
hearing loss
– Second highest rate out
of 25 different industries
(Tak & Calvert, 2008)
– Estimated 25% young
farmers and 50% older
farmers have hearing
loss (Rein, 1992)
Image Source: Indiana Grain LLC, 2008
– Most will have some evidence of hearing
loss by age 30 (Rein, 1992)
Objectives
• Evaluate two-years of data from a 4-year
randomized control study
− A point-sourced intervention designed to increase
hearing protection use.
• Assess the typical noise exposures on the farm
• Evaluate the characteristics of hearing loss
among farmers
• Evaluate the attitudes and beliefs regarding
hearing loss and hearing protection
• Evaluate changes over time
Methods
• Study Design
– Visits at baseline (year one) and at year two
• The following measurements were collected:
 Personal noise dosimetry
 Audiometric testing
 Hearing protection device perception (HPDP)
questionnaire
• Study Population
– Fifty-two farms were recruited and randomized
• Control farms (n=26)
 36 farmers
• Intervention farms (n=26)
 51 farmers
Methods
• Personal Noise Dosimetry Measurements
−Larson Davis dosimeter, Model 706
• Automatically computed into OSHA and NIOSH
standards
Image Source: The Modal Shop, Inc., 2015
Methods
• Audiometric Testing
– Conducted annually on each farm
– Administered by occupational hearing
conservationist
− Stratified into
categories of
hearing loss at
each frequency per
recommendations
by NIOSH
Methods
• Hearing Protection Device Perception
(HPDP) Questionnaire
– Gauged farmers’ attitudes and beliefs about
hearing loss and hearing protection
– Evaluated
•
•
•
•
•
Perceived barriers to preventive actions
Self-efficacy
Social norms
Perceived susceptibility to hearing loss
Perceived severity of consequences of
hearing loss
• Behavioral intentions
Results
• Personal Noise Dosimetry
Figure 1 – Percentage of farmers that exceeded exposure standards
Results
• Substantial amount of variability
− NIOSH’s REL
• More Conservative + More Accurate = More Protective
• Researchers suggests that protective measures should
be taken under all circumstances (Rabinowitz, et. al,
2013)
− Even moderate noise exposures over an extended
period of time could cause permanent hearing loss
Results
• Audiometric Testing
Figure 2 – Frequency distribution of
hearing loss in the left ear for
all farmers at year one.
Figure 3 – Frequency distribution of hearing
loss in the right ear for all farmers
at year one.
25
Number of Farmers
Number of Farmers
25
20
15
10
20
15
10
5
5
0
0
0.5 kHz 1 kHz 2 kHz 3 kHz 4 kHz 6 kHz 8 kHz
Frequency
Mild
Moderate/Severe
Moderate
Severe
0.5 kHz 1 kHz
2 kHz 3 kHz 4 kHz
Frequency
Mild
Moderate/Severe
Moderate
Severe
6 kHz
8 kHz
Results
• Audiometric Testing
− Most considerable hearing loss was observed between 4000
Hz and 6000 Hz
• Typically associated with high frequency noise exposures and
often considered noise-induced hearing loss (Depczynski,
Challinor, & Fragar, 2011)
• Other factors could predict individual susceptibility
− Left ears tended to have more hearing loss than right ears
• Individual behaviors may cause hearing loss to be more
pronounced in one ear over the other (Duarte, 2015)
− No significant change in hearing observed between year one
and year two
• Noise-induced hearing loss is a gradual process
Results
• HPDP Questionnaire
3.00
2.50
2.00
1.50
1.00
Control Farmers Year 1
Intervention Farmers Year 1
Past Behavior
Perceived Barriers Muffled Noise
Percieved Severity of
Consequences
Behavioral Intention
Percieved Benefits to
Preventative Action
Perceived
Susceptibility
Social Norms
Behavioral Intention Future
Self-Efficacy
0.00
Perceived Barriers Comfort
0.50
Control Farmers Year 2
Intervention Farmers Year 2
Figure
3 –– Attitudes
Attitudesand
andbeliefs
beliefsofofthe
thecontrol
controland
and
intervention
farmers
by year
Figure 4
intervention
farmers
by year
Note
Responserefers
referstotothetheaverage
averageresponse
responseshared
sharedbyby
group
each
Note –– Average
Average response
thethe
group
for for
each
yearyear,
1 = Strongly
2 =3 Agree;
3 = Disagree;
and 4 =Disagree
Strongly Disagree
where where
1 = Strongly
Agree; 2Agree;
= Agree;
= Disagree;
and 4 = Strongly
Results
• HPDP Questionnaire
− General observations
• ~ 20% of farmers were uncertain about when to use hearing
protection
• Nearly half of farmers reported that they always used hearing
protection
• All farmers tended to agree that important noises would be muffled
• Consistent with findings by Svensson et al. (2004)
− Differences between intervention and control farmers
• Year one
Control farmers felt more confident about their ability to properly
use hearing protection than intervention farmers (p=0.030)
Intervention farmers agreed more strongly that the consequences
of hearing loss were severe (p=0.019)
• Year two
Intervention farmers disagreed more strongly that comfort was a
barrier to wearing hearing protection (p = 0.010)
Control farmers agreed more strongly that they used earing
protection more while on the job (p = 0.016)
Conclusion
• Farmers are exposed to hazardous noise and have significant
hearing loss
• Only about 50% of farmers actually reported using hearing
protection
• None of the farmers who participated were exposed to noise
in excess of OSHA’s PEL
•
More than half were exposed to noise in excess of NIOSH’s REL
• A statistically significant change in hearing was not observed
•
Subtle changes in attitudes and beliefs
• Provision of personal protective equipment (PPE) and PPE
training appears to be an innovative approach to reduce
hearing loss among farmers
•
Merits further analysis
Acknowledgements
• Dr. Chandran Achutan, PhD, CIH
• Mr. Sean Navarrette, MPH
• This study was supported by a grant from the National
Institute for Occupational Safety and Health (U54
OH010162).
References
Depczynski, J., Challinor, K., & Fragar, L. (2011). Changes in the hearing status and noise injury
prevention practices of australian farmers from 1994 to 2008. Journal of Agromedicine, 16(2),
127-142. doi:10.1080/1059924X.2011.554770
Duarte, A. S. M., Guimarães, A. C., de Carvalho, G. M., Pinheiro, L. A. M., Ng, R. T. Y., Sampaio,
M. H., . . . Gusmão, R. J. (2015). Audiogram comparison of workers from five professional
categories. Biomed Research International, 2015, 201494-201494. doi:10.1155/2015/201494
Indiana Grain LLC. (2008). The American Farmer’s Dirty Little Secret. Retrieved from
http://www.indianagrain.com/blog/the-american-farmer-s-dirty-little-secret
Rabinowitz, P., M., Galusha, D., Dixon-Ernst, C., Clougherty, J., E., & Neitzel, R., L. (2013). The
dose-response relationship between in-ear occupational noise exposure and hearing loss.
Occupational & Environmental Medicine, 70(10), 716-721. doi:10.1136/oemed-2011-100455
Rein, B. K. (1992). Health hazards in agriculture - an emerging issue. Retrieved from
http://nasdonline.org/1246/d001050/health-hazards-in-agriculture-an-emerging-issue.html
Svensson, E. B., Morata, T. C., Nylén, P., Krieg, E. F., & Johnson, A. (2004). Beliefs and attitudes
among Swedish workers regarding the risk of hearing loss. International Journal of Audiology,
43(10), 585-593 9p.
Tak, S., & Calvert, G. M. (2008). Hearing difficulty attributable to employment by industry and
occupation: An analysis of the national health interview survey--united states, 1997 to 2003.
Journal of Occupational and Environmental Medicine, 50(1), 46-56.
doi:10.1097/JOM.0b013e3181579316
The Modal Shop, Inc. (2015). Larson Davis Noise Dosimeters. Retrieved from
http://www.modalshop.com/rental/Spark-Series-Noise-Dosimeters?ID=290
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