Figure 1: (a) Original WNS; (b) WNS-6B; (c) Single question. Odds ratio of the psychiatric cases, identified by the GHQ-28, and its 95% confidence interval with adjustment for gender, age, and socioeconomic status. The population-weighted mean between the insensitive and the sensitive groups in the area under 55 dB was set to the reference. Broken line represents the odds ratio calculated from the pooled data. *P < 0.05