Hearing threshold levels and hearing loss among people in Zhejiang, China: a population-based cross-sectional study

Hearing loss (>= 26 dB threshold in the better ear), as a common chronic condition in humans, is increasingly gaining attention. Relevant research in China is relatively scarce, so we conduct a population-based study to investigate the prevalence of hearing loss among age groups, genders and ears in Zhejiang province, China, from September 2016 to June 2018. Study design Population-based cross-sectional study Participants A total of 3754 participants aged 18-98 years and living in Zhejiang province, China. Outcome measures Pure-tone audiometric thresholds were measured at frequencies of 0.125-8 kHz for each subject. All participants were asked to complete a structured questionnaire, in the presence of a healthcare official. Results The prevalence of speech-frequency and high-frequency hearing loss was 27.9% and 42.9%, respectively, in Zhejiang. There were significant differences in auditory thresholds at most frequencies among the age groups, genders (male vs female: 31.6% vs24.1% at speech frequency; 48.9% vs 36.8% at high frequency) and ears. In addition to the common factors affecting both types of hearing loss, a significant correlation was found between personal income and speech-frequency hearing loss (OR= 0.69, 95% CI 0.52 to 0.92), and between hyperlipidaemia and high-frequency hearing loss (OR= 1.45, 95% CI 1.02 to 2.07). Conclusion The prevalence of hearing loss was high among people living in Zhejiang, particularly males, and in the left ear. Moreover, hearing thresholds increased with age. Several lifestyle and environment factors, which can be influenced by awareness and education, were significantly associated with hearing loss.