Correlation Study Between Mitochondrial DNA4977Fragment Deletion And Noise Induced Hearing Loss Of The Flying Cadets

Flying cadets is a kind of special occupation population, their healthstatus directly affects the fighting capacity for air force. In view of thissituation, Regular health checks, health care, disease intervention anddisease prevention on the groups are very important. Currently, medicalattention of the groups have focused on vision, movement function andcardiovascular system, etc, but for the hearing function examination,prevention and intervention did not receive corresponding attention.Normal auditory function is an important prerequisite for the aircommunication and flight safety. Early damage of auditory function mayhave no subjective symptoms, only by audiology detection can be foundearly. A variety of reasons of hearing impairment of diversity, which maybe congenital genetic factors also may be acquired environmentalfactors(for example, noise, drug and disease etc.). Therefore, we made useof the General Hospital of the Air Force PLA medical support advantageand united aviation medical center lab, relying on the Aviation Universityof air force and air force pilot recruitment team took Audiology detectionfor a batch of flying cadets in Aviation University of air force. We carriedout a cohort study of consecutive tracking for student who had hearing loss,and constructed the gene database for the relevant student. Being finishedthe gene detection that genomics of hearing sensitive and identified factorsrelated to certain diseases, lay the foundation for later research prospectiveseries.We randomly selected140students in Aviation University of air forceas samples for audiological tests, they were all in grade2009. Continuous tracking survey took for two years, we collected the binaural hearingsituation in band250Hz、500Hz、1000Hz、2000Hz、4000Hz、6000Hz、8000Hz for that two years. The emphasis on individual binaural highfrequency change in band4000、6000、8000Hz and high frequency hearingaccumulated value during that two years. Using SPSS19.0took the pairedsamples T test for the high frequency hearing of the groups in that twoyears. P<0.05is considered statistically significant. According to theresults of the change tendency and selected students who hadhigh-frequency hearing loss to take Mitochondrial DNA4977bp deletiondetection which used nested-primer PCR technology. The emphasis was ondiscuss the relationship between mtDNA4977deletion and noise inducedhearing loss and compared the rate of mtDNA4977deletion in hearing lossgroup and normal hearing group, the statistical method used X2test tocompare the rate. We demonstrated the application prospect of NIHL genescreening in physical examination of flying cadet candidates at last.We obtained the conclusion through research:1. There weresignificant differences in the right ear4000Hz of the groups during that twoyear（sP<0.05），the rest of high-frequency band and high frequency hearingaccumulated value showed no statistically significant difference during thattwo years(P＞0.05). We confirmed the existence of noise induced hearingloss in high grade contact initial flight.2. The mtDNA4977deletion rate inhigh-frequency hearing loss group was larger than the normal hearinggroup. X2=21.43，P<0.05. We verified the relationship with mtDNA4977deletion genotype and noise induced hearing loss closely.3. Detection ofnoise induced deafness gene plays an important role in early diagnosis ofhearing loss and prospective study to evaluate the correlation of gene andnoise environment, it can provide a reference for revision of the standardphysical examination of flying cadet candidates.