Table 1 Summary of Selected Characteristics of Reviewed Studies (n = 10)

Reed et al. (2001) [37]

USA

Quasi-experimental crossover design

To test the effectiveness of two sets of instructional materials on farm safety designed through participatory action research involving teachers and students. AgDARE experiential learning curriculum on four disabilities including hearing loss was used. AgDARE used stories told by farmers with disability because of poor safety behavior.

Adolescents aged 14–16 years (9th and 10th graders) from 21 high schools located in rural and agricultural communities in three states (n = 790).

Two intervention groups had 373 participants and 417 were enrolled in the control group.

Yes

Students completed the Farm Safety Attitude (FSA) instrument and the Stages of Change (SOC) at both pre and one year post ntervention phases

Lee et al. (2004) [36]

USA

Cluster randomized controlled trial

To evaluate a rural health & safety initiative implemented in 4000 National FFA (formerly Future Farmers of America) Chapters across the United States.

Rural high school students from 123 FFA chapters (n = 3081)

Standard intervention, enhanced intervention and control groups had 1059, 683 and 1339 participants respectively.

Yes

Students reported safety knowledge, safety consciousness, self-reported leadership, dangerous risk-taking, self-esteem, safety campaign participation, injury experiences at pre and academic year 1 and 2 post-intervention.

Joseph et al. (2007) [38]

USA

Quasi-experimental without control (randomization & manipulation; controlled behavior intervention trial)

To compare the effect of small-group training on the attenuation performance of passive insert-type HPDs with individual training. To compare the results of formal training with no training.

College students from both rural and urban communities (n = 100); demographic characteristics not well-defined.

Each of the four HPD training groups had 25 participants who were randomly assigned into groups.

No

Participants were evaluated for real-ear attenuation at threshold (REAT) at third-octave noise band between 125 and 8000 Hz. REAT measurements were augmented by the use of Hearing Loss Prevention Attitude-Belief (HLPAB) survey.

Berg et al. (2009) [33]

USA

Cluster randomized controlled trial

To determine whether a hearing conservation program for youth involved in farm work resulted in (i) reduced prevalence of NIHL at 3-year follow up and/or (ii) an increased use of HPD when compared with controls.

Rural school students enrolled in 7th to 9th grades and actively and regularly involved in farm tasks (n = 753).

Intervention and control groups had 378 and 375 students respectively from 34 schools at baseline although 690 were available at follow-up.

Yes

Primary outcome measures were audiometric threshold changes from baseline to the 3-year follow-up whereas secondary outcome measure was self-reported use of HPD using a three point Likert-type scale (never, sometimes, and always).

Kotowski et al. (2011) [39]

USA

Randomized experimental study with two group post-test only design

To determine if brochures developed on the risks of NIHL using the Extended Parallel Process Model (EPPM) increased intentions to use HPDs for college students.

Undergraduate college students exposed to noises from sporting and recreational sources (n = 176). Study setting (i.e. urban or rural) remained undefined.

Subjects were randomly put into intervention (n = 93) and control (n = 83) conditions.

Yes

Participants reported perceptions of hearing loss threat, efficacy to use earplugs and intentions to use earplugs when in loud environments.

Marlenga et al. (2011) [24]

USA

Cluster randomized controlled trial

To assess whether a hearing conservation program for youth involved in farm work resulted in reduced prevalence of NIHL and sustained HPD use compared with a concurrent control group at the 16-year follow-up period.

Young adults (at 16-year follow-up) who were high or middle school students located in rural and agricultural communities at baseline (n = 392).

Children from 17 intervention school and equal number of control schools were available at the follow-up. Intervention and control groups had 200 and 192 participants respectively during follow-up data collection.

Yes

Self-reported use of HPD for each recreational and occupational categories was used as the primary outcome measures. Audiometric outcome measures were threshold changes from baseline to 16-year follow-up in (1) individual frequencies, (2) OSHA standard threshold shift, (3) low frequency average, (4) high-frequency average, and (5) the bulge depth statistic.

Martin et al. (2013) [27]

USA

Experimental study with randomized selection of groups

To evaluate the sustainable impacts of four different types of interpersonal and interactive educational interventions on NIHL prevention from baseline to immediate post-intervention and follow-up.

Children from 53 fourth grade classrooms participated in the study (n = 1120). Schools were located in communities with high-minority and under-represented populations.

Classrooms were randomly placed into four experimental and one no-intervention groups. Number of classrooms (children) analyzed: older peer 13 (272), health educator 10 (209), on site museums 9 (185), web-based 15 (322), and no-intervention 6 (125).

Yes

Knowledge, attitudes and intended behaviors regarding sound exposure and use of appropriate hearing protection strategies were the outcome measures assessed via questionnaire survey.

Gilles et al. (2014) [34]

Belgium

Quasi-experimental one-group pre/post test

To examine if a preventive campaign can alter attitudes toward noise and enhance the use of HPD among adolescents.

Flemish high school students (n = 547) exposed to high levels of recreational noise. Study setting (i.e. urban or rural) remained undefined.

Not applicable as only one group was observed before and after intervention.

No

Youth attitudes and beliefs were assessed by the use of youth attitudes toward noise scale (YANS) and the beliefs about hearing protection and hearing loss (BAHPHL) questionnaire respectively. Self-reported hearing protection was also recorded.

Keppler et al. (2015) [40]

Belgium

Experimental study with one group

To evaluate the effects of a hearing education program on recreational noise exposure, attitudes and beliefs toward noise, hearing loss, and HPD use after approximately 6 months following training.

Young adults (n = 78) exposed to loud recreational noise. Study setting (i.e. urban or rural) was not defined.

Not applicable as only one group was observed at pre and post training.

No

Hearing status was determined by admittances measures, pure-tone audiometry, and registration of otoacoustic emissions (OAEs).

Khan et al. (2018) [35]

USA

Experimental study with cluster randomization

To evaluate the efficacy of low-cost technology-based approaches to enhance hearing conservation knowledge and attitude and the use of HPD among adolescent farm workers.

High school students living in rural and agricultural communities (n = 70).

Six schools were divided into three clusters and then each cluster randomly received a specific format of intervention. Adolescents were randomly recruited from each school. Fifty students from three groups were available at six-week post intervention.

No

Self-reported hearing conservation knowledge, attitude and use of hearing protection during noisy tasks in agriculture.