关键词: 耳疾病, 听力损失, 用耳习惯, 娱乐性噪声, 耳机, 医学生

Abstract: Background　Recently，many studies have assessed the hearing loss （HL） of elderly people，people across occupational groups，and infants，but few have assessed this issue among medical students in China.Objective　To investigate the status of HL and hearing related symptoms among medical students，and to explore the effect of hearing habits on them.Methods　A total of 1 882 students of four-year （freshman-junior students） and five-year （freshman-senior students） graduation systems were selected by cluster sampling in Medical School，Hangzhou Normal University from March to May 2017.The questionnaire survey and pure-tone hearing tests（PTT）were conducted.The questionnaire comprised three parts：demographic characteristics （age，sex，major，grade），the hearing related symptoms（the occurrence of tinnitus，earache and aural fullness in the last year），and hearing habits（whether to use headphones，type of headphones，frequency of headphone usage，time of headphone usage，time of playing games with headphones，maximum volume of headphone，mode of cell phone conversation，noise environment to improve headphone volume，sleeping with headphones listening to music/radio，frequency of going entertainment places）．The sound-pressure levels of background noise measured at a dedicated sound-isolating room in the university laboratory building were below 30 dB.PTT were measured using a calibrated audiometer （AT235） with standard headphones （TDH-39P）．The speech-frequency HL （>25 dB）and high-frequency HL （>25 dB） were assessed.Factors influencing HL and hearing related symptoms were analyzed by multivariate Logistic regression models.Results　A total of 1 882 questionnaires were sent out，1 882 questionnaires were recovered，1 882 questionnaires were valid，with an effective recovery rate of 100.0%.Pure-tone averages of the right ear were higher than those of the left ear at hearing frequency of 0.125，0.250，0.500，1.000，2.000，4.000，6.000 kHz（P<0.05）．The number of students with speech frequency hearing loss （> 25 dB） was 32 （1.7%），high frequency hearing loss （> 25 dB） was 62 （3.3%），tinnitus was 913 （48.5%），earache was 533 （28.3%） and aural fullness was 502 （26.7%）．Among 1 664 medical students（88.4%）who used headphones，there were 963 （57.9%），610 （36.6%） and 91（5.5%） medical students used earplug，in-ear headphones or headset，respectively.The number of students with frequency of using earphones > 2 times/d was 513（27.3%）.Duration of using earphones was >1.0 h/d among 289 medical students（15.4%）．Duration of playing games with using earphones was ≥1 h/d among 547 medical students（29.1%）．Maximum volume of using earphones was ≥60% among 70 medical students（3.7%）．The number of students making phone calls by earphones was 521（27.6%）．Probability to increase earphone volume in a noisy environment was ≥50% among 1 142 medical students（60.7%）．Frequency of sleeping with earphones while listening to music or broadcast was ≥2 times/week among 158 medical students（8.4%）．Frequency of attending entertainment venues was >3 times/month among 36 medical students（1.9%）．The speech-frequency HL and high-frequency HL rates of the tinnitus group were higher than those in the non-tinnitus group（P<0.05）．The speech-frequency HL and high-frequency HL rates did not show any significant difference among ear pain，and aural fullness（P>0.05）．Sex〔female：OR=0.467，95%CI（0.267，0.816）〕was a factor affecting speech-frequency HL among medical students（P<0.05）．Probability to increase earphone volume in a noisy environment〔≥50%：OR=1.567，95%CI（1.282，1.915）〕 was a factor influencing tinnitus among medical students（P<0.05）．Frequency of using earphones〔>2 times/d：OR=1.443，95%CI（1.151，1.810）〕，and duration of using earphones 〔0.5-1.0 h/time：OR=1.447，95%CI（1.151，1.818）；>1.0 h/times：OR=1.648，95%CI（1.214，2.237）〕were factors of ear pain among medical students（P<0.05）．Sex 〔female：OR=1.338，95%CI（1.061，1.686）〕，duration of playing games with earphones〔≥1 h/d：OR=1.315，95%CI（1.053，1.642）〕，probability to increase earphone volume in a noisy environment〔≥50%：OR=1.398，95%CI（1.126，1.735）〕，and frequency of attending entertainment venues 〔>3 times/month：OR=3.324，95%CI（1.686，6.554）〕were factors for aural fullness among medical students（P<0.05）．Conclusion　The hearing status is not optimistic among medical students.The hearing status of the right ear is worse than that of the left ear.Improper usage of earphones and exposure to damaging sound levels at noisy entertainment venue can cause hearing damage.Bad hearing habits have long-term influence on the hearing of medical students.We suggest that qualified schools add PTT to the entrance examination，and strengthen the health education related to hearing.

Key words: Ear diseases, Hearing loss, Hearing habit, Recreational noise, Earphone, Medical student