Improved Hearing Protection Regulations in the Prevention of Military NIHL and Tinnitus

1. Improved Hearing Protection Regulations in the Prevention of Military NIHL and Tinnitus Roderik Mrena, MD University of Helsinki, Finland February 26, 2010 Rosen Plaza Hotel, Orlando, FL

6. Occupational NIHL in Finland

7. Occupational NIHL severity • occupational NIHL cases are reported to the National Insurance Board • mostly mild

8. Occupational NIHLMrena, Ylikoski M, Mäkitie A, Pirvola, Ylikoski J. Occupational NIHL reports and tinnitus in Finland. Acta Otolaryngol 2007, Vol. 127, No. 7, p.729-735. • hearing loss = compensation • tinnitus ≠ compensation

9. Background • military proffessional are at risk of NIHL • awareness ↑ • EU Directive 2003/10/EC (effective 2006) • lower exposure action value: 80 dB(A), 135 dB(C) • protectors available, possibility for AG • upper exposure action value: 85 dB(A), 137 dB(C) • protectors mandatory, noise cancellation program • exposure limit value: 87 dB(A), 140 dB(C) • exposure may not exceed

10. Regulations in the FDF • 1968 • hard ammunition • 1979 • muffs in firing range, plugs in combat training • 1985 • also with blanks • 1989, 1991 • supervisor must order usage (but own responsibility) • education • still, annually 1-2% of conscripts suffer AAT • consequences • effective in preventing hearing loss / tinnitus?

11. Subjects • 246 military personnel ending active duty • Period 1 (1984-1986): n=123 • Period 2 (2003-2005): n=129 • retrospective review of medical records • AG • exposure time • ear symptoms

12. Subjects

13. Results – Hearing LossMrena R, Ylikoski J, Kiukaanniemi H, Mäkitie A, Savolainen S. The effect of improved hearing protection regulations in the prevention of military NIHL. Acta Oto-Laryngol 2008;128:997-1003. • hearing generally worse in the left ear • NCOs • improvement in both ears • statistically significant • Officers • improvement, but statistically insignificant

14. NCOs – Right Ear

15. NCOs – Left Ear

16. Regulations & TinnitusMrena R, Savolainen S, Kiukaanniemi H, Ylikoski J, Mäkitie A. The effect of tightened hearing protection regulations on military noise-induced tinnitus. Int J Audiol 2009;48:394-400.

17. Results – Tinnitus Prevalence • Total Tinnitus Prevalence • Period I (1984-1986): 71% • Period II (2003-2005): 68% • Officers • Period I: 68% • Period II: 63% • NCOs • Period I: 76% • Period II: 72% • significance

18. Results – Severe Tinnitus • division: • no tinnitus / mild / constant or disturbing • constant or disturbing tinnitus Period II vs. I: • Cox regression analysis: • HR 0.6, 95% CI 0.37-0.96, p=0.032

19. Results – Tinnitus Questionnaire • available only during Period II (2003-2005) • localization: left 46% right 30% both 23% • high-pitched 90%

20. Tinnitus – Related Problems

21. Conclusions • regulations are effective in reducing hearing loss • regulations are effective in reducing serious tinnitus • tinnitus prevalence did not improve in direct relation to hearing loss improvement • retiring military professionals are young • NIHL & tinnitus are a serious threat to the quality of life - preventable !

22. Significance of Long-Term TinnitusMrena R, Savolainen S, Kuokkanen J, Ylikoski J. Characteristics of tinnitus induced by acute acoustic trauma: a long-term follow-up. Audiol Neurotool 2002;7:122-130. • 418 conscripts with AAT: 100% tinnitus • 15 years later: 65% tinnitus

23. Results – Possible Factors • actual use of protectors • reasons? • leisure activities?

24. Always Wear Hearing Protection!

25. Thank you !