The heritability of age-related hearing loss has been studied mostly in developed countries. The authors aimed to estimate the heritability of better ear hearing level (BEHL), defined as hearing level of the better ear at a given frequency, and pure-tone averages at the middle (0.5, 1.0, and 2.0 kHz) and high (4.0, 8.0, and 12.5 kHz) frequencies among middle-aged and elderly Chinese twins, and to explore their genetic correlations.
This population-based twin study included 226 monozygotic and 132 dizygotic twin-pairs and 1 triplet (age range, 33 to 80 years; mean age, 51.55 years). Pure-tone air-conducted hearing thresholds in each ear were measured at the frequencies of 0.5, 1.0, 2.0, 4.0, 8.0, and 12.5 kHz with a diagnostic audiometer. Univariate and multivariate twin models were fitted to evaluate heritability and genetic correlations.
Our data showed a reverse J-shaped pattern of BEHLs at six frequencies by age and sex. Univariate analysis showed that the heritability of BEHLs at the frequencies between 2.0 and 12.5 kHz ranged from 47.08 to 54.20%, but the heritability at the frequencies of 0.5 and 1.0 kHz was 1.65% and 18.68%, respectively. The heritability of pure-tone average at the middle and high frequencies was 34.77% and 43.26%, respectively. Multivariate analysis showed significant genetic correlations among BEHLs at all six frequencies, with the correlation coefficients ranging from 0.48 to 0.83 at middle frequencies, and from 0.46 to 0.75 at high frequencies.
This population-based twin study suggests that genetic factors are associated with age-related hearing loss at middle and high frequencies among middle-aged and elderly Chinese.
1Department of Epidemiology and Health Statistics, Qingdao University School of Public Health, Qingdao, Shandong, China
2Qingdao Center for Disease Control and Prevention, Qingdao, Shandong, China
3Aging Research Center, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet-Stockholm University, Stockholm, Sweden
4Department of Public Health Sciences, Karolinska Institutet, Stockholm, Sweden
5Unit of Human Genetics, Department of Clinical Research, University of Southern Denmark, Odense, Denmark
6Epidemiology and Biostatistics, Department of Public Health, University of Southern Denmark, Odense, Denmark.
Received October 31, 2016; accepted March 30, 2018.
The authors have no conflicts of interest to disclose.
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Address for correspondence: Dongfeng Zhang, Department of Public Health, Qingdao University Medical College, Dengzhou Street 38, Qingdao 266021, Shandong, China. E-mail: email@example.com; or Chengxuan Qiu, Aging Research Center, Karolinska Institutet, Tomtebodavägen 18, 171 65 Solna, Sweden. E-mail: firstname.lastname@example.org