A Multilevel Intervention to Prevent Noise Exposure in Farmworkers

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.

• Multilevel Hearing Protection Training (Behavioral), also known as Protected Ears Project (PEP): 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.

Primary outcomes

• Change in Time-Weighted Average Noise Exposure (dBA) [Baseline and approximately 1 month post-intervention]: 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.
• Change in Noise Dose (%) [Baseline and approximately 1 month post-intervention]: Cumulative occupational noise exposure measured as percent noise dose using personal dosimeters worn during a full work shift, calculated using standard NIOSH criteria.

Secondary outcomes

• Change in Hearing Protection Beliefs and Attitudes [Baseline and approximately 1 month post-intervention]: 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.
• Acceptability of the Hearing Protection Training [Approximately 1 month post-intervention]: 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.
• Appropriateness of the Hearing Protection Training [Approximately 1 month post-intervention]: 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.
• Feasibility of the Hearing Protection Training [Approximately 1 month post-intervention]: 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.

Sex: All, ages: 18 Years to any, accepts healthy volunteers

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)

NIH grants: K23DC022303