The Study of Health Effects from Noise Generated in China (SHENG): design and methods

Noise-induced hearing loss (NIHL) is the second most prevalent occupational disease in China. Due to its insidious onset, patients are often diagnosed at an irreversible stage, yet high-quality prospective cohorts addressing this critical issue remain limited. We established a multicenter prospective cohort-the Study of Health Effects from Noise Generated in China (SHENG)-with the primary objectives of systematically characterizing the epidemiological features, identifying environmental and genetic risk factors, elucidating molecular mechanisms, and investigating systemic health effects of NIHL, ultimately providing a scientific foundation for evidence-based prevention and control strategies. The baseline survey of SHENG was completed in 2023, covering eight enterprises across seven provinces and enrolling 4,660 young male workers (mean age 23.5 years). Based on high-frequency pure-tone average (3-8 kHz), 27.4% of participants were classified as having hearing loss, though most of them did not report subjective hearing difficulties. Compared with the normal hearing group, the hearing loss group had significantly more noise exposure events, higher exposure rates to occupational co-hazards such as dust and vibration, and poorer hearing protection practices. SHENG is planned to conduct follow-up assessments every 1-2 years. Through longitudinal follow-up and multidimensional data integration, this cohort will establish an "environmental-clinical-genetic" risk assessment model, elucidate the dynamic progression of NIHL and its associations with systemic diseases, and provide key evidence for refining occupational noise exposure standards and developing precision prevention strategies tailored to susceptible populations.