A Multilevel Intervention to Prevent Noise Exposure in Farmworkers (POP)

This study will test a program to reduce noise exposure and prevent hearing loss among farmworkers. Farmworkers are often exposed to high levels of noise from machinery, which can lead to hearing loss over time.

Farms will be randomly assigned to either receive the program or serve as a comparison group. The program includes a short educational video, group discussion, and hands-on training on how to use hearing protection (such as earplugs). Supervisors will also receive brief training on how to support hearing protection use in the workplace.

Participants will wear a small device (dosimeter) during a work shift to measure noise exposure before the program and again about one month later. Participants will also complete surveys about their knowledge, attitudes, and behaviors related to hearing protection.

A subset of participants will be invited to take part in interviews to understand barriers and facilitators to using hearing protection and implementing the program.

The results of this study will help inform future efforts to improve hearing health and reduce noise exposure in agricultural settings.

Study Overview

• Status: Not yet recruiting
• Conditions: Occupational Exposure; Noise Exposure; Hearing Loss, Noise-Induced
• Intervention / Treatment: Behavioral: Multilevel Hearing Protection Training

Detailed Description

This study is a cluster randomized controlled trial designed to evaluate a multilevel intervention to reduce occupational noise exposure among farmworkers. Farms will be recruited through community and industry partnerships and randomized in a 1:1 ratio to either the intervention or control condition. Randomization will occur at the farm level to minimize contamination.

The intervention includes both worker- and supervisor-level components. Farmworkers will participate in a training session consisting of a brief educational video on noise exposure and hearing loss, followed by group discussion and hands-on instruction on proper use of hearing protection. Supervisors will receive a brief training focused on identifying noise hazards, promoting hearing protection use, and supporting workplace-level safety practices.

Control sites will not receive the intervention during the study period but will be offered the program after study completion.

Primary outcomes include objective measures of noise exposure assessed using personal dosimeters worn during a full work shift at baseline and approximately one month post-intervention. Dosimeters measure time-weighted average noise exposure, noise dose, and peak sound levels and do not record audio.

Secondary outcomes include farmworker knowledge, attitudes, self-efficacy, and behaviors related to hearing protection, as well as supervisor-level outcomes related to supporting hearing safety. Worksite-level outcomes include availability of hearing protection and presence of noise hazard indicators.

A qualitative component will be conducted with a subset of participants, including farmworkers, supervisors, and external stakeholders, to assess barriers and facilitators to implementation. Interviews will be conducted in participants' preferred language, audio-recorded with consent, and analyzed using established implementation science frameworks.

This study will provide preliminary evidence on the effectiveness and feasibility of a multilevel intervention to reduce noise exposure in agricultural settings and inform future large-scale trials.

• Study Type: Interventional
• Enrollment (Estimated): 200
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Laura Coco, PhD, AuD; Phone Number: 16195943151; Email: lcoco@sdsu.edu

Study Locations

• United States
  • California
    • San Diego, California, United States, 92182
      • San Diego State University
      • Contact: Laura Coco, PhD, AuD; Phone Number: 619-594-3151; Email: lcoco@sdsu.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Age 18 years or older
• Currently employed as a farmworker or supervisor at a participating farm
• Able to provide informed consent
• Able to understand and communicate in Spanish or English

Exclusion Criteria:

• Not currently working at a participating farm at the time of recruitment
• Unable or unwilling to wear a personal noise dosimeter during a work shift
• Unable to complete study procedures (e.g., surveys or training)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Intervention Arm (Multilevel Intervention Group); Participants at farms assigned to the intervention arm will receive a multilevel intervention that includes a brief educational video on noise exposure and hearing loss, group discussion, and hands-on training on proper use of hearing protection (e.g., earplugs). Supervisors will receive a brief training on identifying noise hazards and supporting hearing protection use among workers. The intervention is delivered in a community or workplace setting by trained study staff or community health workers.	Behavioral: Multilevel Hearing Protection Training; The intervention is a multilevel behavioral training program designed to reduce occupational noise exposure and promote hearing protection use. Farmworkers participate in a session that includes a brief educational video on noise exposure and hearing loss, group discussion, and hands-on instruction on proper use of hearing protection (e.g., earplugs). Supervisors receive a brief training on identifying noise hazards and supporting hearing protection use among workers. The intervention is intended to be delivered in a group or 1:1 setting by trained research staff or community health workers.; Other Names: Protected Ears Project (PEP)
No Intervention: Control Arm (Usual Practice); Participants at farms assigned to the control arm will not receive the intervention during the study period. They will complete study assessments, including dosimetry and surveys. The intervention will be offered after study completion.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Time-Weighted Average Noise Exposure (dBA)	Objective occupational noise exposure measured using personal dosimeters worn during a full work shift. The primary metric is time-weighted average (TWA) noise exposure in decibels (dBA), calculated using standard NIOSH criteria. Devices do not record audio, only noise levels.	Baseline and approximately 1 month post-intervention
Change in Noise Dose (%)	Cumulative occupational noise exposure measured as percent noise dose using personal dosimeters worn during a full work shift, calculated using standard NIOSH criteria.	Baseline and approximately 1 month post-intervention

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Hearing Protection Beliefs and Attitudes	Change in self-reported beliefs and attitudes toward hearing protection use, assessed using the 14-item Hearing Protection Beliefs scale. Items are rated on a 4-point Likert scale (1 = disagree to 4 = strongly agree) and summed after reverse-coding negatively worded items. Total scores range from 14 to 56, with higher scores indicating more favorable and accurate beliefs about hearing protection.	Baseline and approximately 1 month post-intervention
Acceptability of the Hearing Protection Training	Participant-reported acceptability of the training assessed immediately post-training using the Acceptability of Intervention Measure (AIM). The AIM consists of 4 items rated on a 5-point Likert scale (1 = completely disagree to 5 = completely agree). Item responses are averaged to generate a mean score ranging from 1 to 5, with higher scores indicating greater perceived acceptability of the training.	Approximately 1 month post-intervention
Appropriateness of the Hearing Protection Training	Participant-reported appropriateness of the training assessed immediately post-training using the Intervention Appropriateness Measure (IAM). The IAM consists of 4 items rated on a 5-point Likert scale (1 = completely disagree to 5 = completely agree). Item responses are averaged to generate a mean score ranging from 1 to 5, with higher scores indicating greater perceived appropriateness of the training.	Approximately 1 month post-intervention
Feasibility of the Hearing Protection Training	Participant-reported feasibility of the training assessed immediately post-training using the Feasibility of Intervention Measure (FIM). The FIM consists of 4 items rated on a 5-point Likert scale (1 = completely disagree to 5 = completely agree). Item responses are averaged to generate a mean score ranging from 1 to 5, with higher scores indicating greater perceived feasibility of the training.	Approximately 1 month post-intervention

Collaborators and Investigators

• Sponsor: San Diego State University
• Collaborators: National Institute on Deafness and Other Communication Disorders (NIDCD)

Study record dates

Study Major Dates

• Study Start (Estimated): October 1, 2026
• Primary Completion (Estimated): January 1, 2031
• Study Completion (Estimated): July 1, 2032

Study Registration Dates

• First Submitted: April 21, 2026
• First Submitted That Met QC Criteria: April 21, 2026
• First Posted (Actual): April 28, 2026

Study Record Updates

• Last Update Posted (Actual): April 28, 2026
• Last Update Submitted That Met QC Criteria: April 21, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: Cluster randomized trial; implementation science; Community Health Workers; Workplace intervention; agriculture; earplugs; occupational noise; farmworkers; hearing protection; hearing conservation
• Additional Relevant MeSH Terms: Neurologic Manifestations; Nervous System Diseases; Otorhinolaryngologic Diseases; Sensation Disorders; Ear Diseases; Hearing Loss; Hearing Disorders; Hearing Loss, Sensorineural; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Hearing Loss, Noise-Induced
• Other Study ID Numbers: IRB-26-181; 1K23DC022303-01A1 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED
• IPD Plan Description: De-identified individual participant data may be shared in the future with qualified researchers upon reasonable request, subject to appropriate data use agreements and protections for participant confidentiality. Due to the small sample size and recruitment within specific worksites, there is a potential risk of re-identification; therefore, data will not be publicly posted and will only be shared in a controlled manner.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No