Evaluation of a hearing conservation program for farm youth: A 16-year follow-up

Agriculture has among the highest recorded exposures to dangerous levels of noise. Studies have demonstrated an increased prevalence of noise-induced hearing loss (NIHL) among youth actively involved in farm work. Since most agricultural worksites are exempt from safety and health regulations, alternative strategies to promote hearing conservation among farm youth must be identified. We are evaluating the long-term effectiveness of a three-year hearing conservation program for farm youth conducted between 1992 and 1996 in Wisconsin, USA. Thirty-four rural schools had been recruited and randomized to intervention or control. The intervention included classroom instruction, distribution of hearing protection devices, direct mailings, noise level assessments, and yearly audiometric testing. The control group received the audiometric testing. In total, 690 high school farm youth completed the study. Students exposed to the hearing conservation program reported increased use of hearing protection devices (OR 7.73; 95% CI: 4.98 to 11.99), but there was no evidence of reduced levels of NIHL where odds ratios varied between 0.88 (95% CI: 0.58 to 1.34) at 3000 HZ to 1.55 (0.89 to 2.69) at 4000 HZ. Since NIHL is cumulative, a three-year study was likely not long enough to evaluate the efficacy of this intervention. A 16-year follow-up study of this hearing conservation program cohort is currently underway. To date, 356 former students have been recruited and enrolled. The results of this long-term follow-up will be available by November, 2010 and will demonstrate the role of early intervention in sustaining hearing protection behaviors and preventing NIHL in young workers.