Randomized trial of a hearing conservation intervention for rural students: long-term outcomes.
Marlenga-B; Linneman-JG; Pickett-W; Wood-DJ; Kirkhorn-SR; Broste-SK; Knobloch-MJ; Berg-RL
Pediatrics 2011 Nov; 128(5):e1139-e1146
OBJECTIVES: We had the rare opportunity to conduct a cluster-randomized controlled trial to observe the long-term (16-year) effects of a well-designed hearing conservation intervention for rural high school students. This trial assessed whether the intervention resulted in (1) reduced prevalence of noise-induced hearing loss (NIHL) assessed clinically and/or (2) sustained use of hearing protection devices. METHODS: In 1992-1996, 34 rural Wisconsin schools were recruited and 17 were assigned randomly to receive a comprehensive, 3-year, hearing conservation intervention. In 2009-2010, extensive efforts were made to find and contact all students who completed the original trial. Participants in the 16-year follow-up study completed an exposure history questionnaire and a clinical audiometric examination. Rates of NIHL and use of hearing protection were compared. RESULTS: We recruited 392 participants from the original trial, 200 (53%) from the intervention group and 192 (51%) from the control group. Among participants with exposure to agricultural noise, the intervention group reported significantly greater use of hearing protection compared with the control group (25.9% vs 19.6%; P = .015). The intervention group also reported significantly greater use of hearing protection for shooting guns (56.2% vs 41.6%; P = .029), but the groups reported similar uses of protection in other contexts. There was no significant difference between groups with respect to objective measures of NIHL. CONCLUSION: This novel trial provides objective evidence that a comprehensive educational intervention by itself may be of limited effectiveness in preventing NIHL in a young rural population.
Agricultural-industry; Agricultural-workers; Agriculture; Audiological-testing; Audiometry; Education; Exposure-assessment; Exposure-levels; Exposure-methods; Hearing; Hearing-conservation; Hearing-level; Hearing-protection; Hearing-tests; Noise; Noise-induced-hearing-loss; Noise-exposure; Noise-levels; Noise-sources; Work-areas; Work-environment; Work-operations; Work-practices; Ear-protection; Ear-protectors; Age-groups;
Author Keywords: agriculture; hearing conservation; noise-induced hearing loss; youths; randomized controlled trial
Barbara Marlenga, National Farm Medicine Center, Marshfield Clinic Research Foundation, 1000 North Oak Avenue, Marshfield, WI 54449
Marshfield Clinic Research Foundation