Cigarette- and snus-modified association between unprotected exposure to noise from hunting rifle caliber weapons and high frequency hearing loss. A cross-sectional study among swedish hunters.

AIM: To investigate in this cross-sectional study among Swedish hunters if tobacco use modifies the previously observed association, expressed as prevalence ratio (PR), between unprotected exposure to impulse noise from hunting rifle caliber (HRC) weapons and high-frequency hearing impairment (HFHI). SETTINGS AND DESIGN: A nationwide cross-sectional epidemiologic study was conducted among Swedish sport hunters in 2012. MATERIALS AND METHODS: The study was Internet-based and consisted of a questionnaire and an Internet-based audiometry test. RESULTS: In all, 202 hunters completed a questionnaire regarding the hearing test. Associations were modeled using Poisson regression. Current, daily use of tobacco was reported by 61 hunters (19 used cigarettes, 47 moist snuff, and 5 both). Tobacco users tended to be younger, fire more shots with HRC weapons, and report more hunting days. Their adjusted PR (1-6 unprotected HRC shots versus 0) was 3.2 (1.4-6.7), P < 0.01. Among the nonusers of tobacco, the corresponding PR was 1.3 (0.9-1.8), P = 0.18. P value for the interaction was 0.01. The importance of ear protection could not be quantified among hunters with HRC weapons because our data suggested that the HFHI outcome had led to changes in the use of such protection. Among hunters using weapons with less sound energy, however, no or sporadic use of hearing protection was linked to a 60% higher prevalence of HFHI, relative to habitual use. CONCLUSION: Tobacco use modifies the association between exposure to unprotected impulse noise from HRC weapons and the probability of having HFHI among susceptible hunters. The mechanisms remain to be clarified, but because the effect modification was apparent also among the users of smokeless tobacco, combustion products may not be critical for this effect.

Shooting history and presence of high-frequency hearing impairment in swedish hunters: A cross-sectional internet-based observational study.

The aim of this cross-sectional study among Swedish hunters was to examine the association between shooting history and presence of high-frequency hearing impairment (HFHI). All hunters registered with an e-mail address in the membership roster of the Swedish Hunters' Association were invited via e-mail to a secure website with a questionnaire and an Internet-based audiometry test. Associations, expressed as prevalence ratio (PR), were multivariately modelled using Poisson regression. The questionnaire was answered by 1771 hunters (age 11-91 years), and 202 of them also completed the audiometry test. Subjective severe hearing loss was reported by 195/1771 (11%), while 23/202 (11%) exhibited HFHI upon testing with Internet-based audiometry. As many as 328/1771 (19%) had never used hearing protection during hunting. In the preceding 5 years, 785/1771 (45%), had fired >6 unprotected gunshots with hunting rifle calibers. The adjusted PR of HFHI when reporting 1-6 such shots, relative to 0, was 1.5 [95% confidence interval (CI) 1.1-2.1; P = 0.02]. We could not verify any excessive HFHI prevalence among 89 hunters reporting unprotected exposure to such gunshot noise >6 times. Nor did the total number of reported rifle shots seem to matter. These findings support the notion of a wide variation in individual susceptibility to impulse noise; that significant sound energy, corresponding to unprotected noise from hunting rifle calibers, seems to be required; that susceptible individuals may sustain irreversible damage to the inner ear from just one or a few shots; and that use of hearing protection should be encouraged from the first shot with such weapons.

An internet-based hearing test for simple audiometry in nonclinical settings: preliminary validation and proof of principle.

OBJECTIVE: To investigate the validity and reproducibility of a newly developed internet-based self-administered hearing test using clinical pure-tone air-conducted audiometry as gold standard. STUDY DESIGN: Cross-sectional intrasubject comparative study. SETTING: Karolinska University Hospital, Solna, Sweden. PATIENTS: Seventy-two participants (79% women) with mean age of 45 years (range, 19-71 yr). Twenty participants had impaired hearing according to the gold standard test. INTERVENTIONS: Hearing tests. MAIN OUTCOME MEASURES: The Pearson correlation coefficient between the results of the studied Internet-based hearing test and the gold standard test, the greatest mean differences in decibel between the 2 tests over tested frequencies, sensitivity and specificity to diagnose hearing loss defined by Heibel-Lidén, and test-retest reproducibility with the Pearson correlation coefficient. RESULTS: The Pearson correlation coefficient was 0.94 (p < 0.0001) for the right ear and 0.93 for the left (p = 0.0001). The greatest mean differences were seen for the frequencies 2 and 4 kHz, with -5.6 dB (standard deviation, 8.29), and -5.1 dB (standard deviation, 6.9), respectively. The 75th percentiles of intraindividual test-gold standard differences did not exceed -10 dB for any of the frequencies. The sensitivity for hearing loss was 75% (95% confidence interval, 51%-90%), and the specificity was 96% (95% confidence interval, 86%-99%). The test-retest reproducibility was excellent, with a Pearson correlation coefficient of 0.99 (p < 0.0001) for both ears. CONCLUSION: It is possible to assess hearing with reasonable accuracy using an Internet-based hearing test on a personal computer with headphones. The practical viability of self-administration in participants' homes needs further evaluation.

Evaluation of an internet-based hearing test--comparison with established methods for detection of hearing loss.

BACKGROUND: Hearing impairment is most accurately measured by a clinical pure-tone audiogram. This method is not suitable for large-scale, population-based epidemiological studies as it requires that study participants visit a clinic with trained personnel. An alternative approach to measuring hearing ability is self-estimation through questionnaires, but the correlation to clinical audiometric tests varies. OBJECTIVE: To evaluate an Internet-based hearing test pilot compared to a question about self-estimated hearing and the feasibility of using an Internet-based hearing test and an Internet-based questionnaire in a population of 560 members of the Swedish Hunters' Association in the age group 20-60 years. METHODS: An invitation was mailed to the participants in March 2007 together with the URL to the study Web site, a personal username, and a password. The Web site included the questionnaire, the hearing test, and instructions for participating in the study. The hearing test resembles a clinical audiogram presenting 6 tones between 500 and 8000 Hz. Tones are presented between 0 and 60 dB, and the participant responds to the tones by pressing the space bar. The hearing test requires headphones and is based on JAVA programming. Before the participant can start the hearing test, it has to be calibrated against a reference person with good hearing between 15 and 35 years of age. RESULTS: After 5 months, 162 out of 560 (29%) had answered the questionnaire, out of which 88 (16%) had completed the hearing test. Those who actively declined participation numbered 230 out of 560 (41%). After removing duplicates and hearing tests calibrated by unreliable reference data, 61 hearing tests remained for analysis. The prevalence of hearing impairment from the Internet-based hearing test was 20% (12 out of 61), compared to 52% (32 out of 61) from the self-estimated question. Those who completed the hearing test were older than the non-participants, and more had headphones (P = .003) and the correct version of the JAVA program (P = .007) than those who only answered the questionnaire. CONCLUSIONS: Though an Internet-based hearing test cannot replace a clinical pure-tone audiogram conducted by a trained audiologist, it is a valid and useful screening tool for hearing ability in a large population carried out at a low cost.