ABSTRACT
A questionnaire study was conducted in a residential area along trunk roads in Kusatsu, Japan, in order to investigate the association between noise exposure, noise sensitivity, and subjective health. Subjective health of the respondents was measured by the General Health Questionnaire (GHQ-28) which yields the total score as an index of psychiatric disorder and four subscales. Noise sensitivity was measured by the improved version of the Weinstein's noise sensitivity scale named WNS-6B. The original WNS and a single question directly asking respondents' noise sensitivity were also applied to confirm the validity of the WNS-6B for investigating the effects of road traffic noise on subjective health. Respondents were also asked about disturbances of daily life due to noise exposure to find the cause of the health effects. Three hundred and twenty three answers were entered into the analysis. Applying the WNS-6B as the noise sensitivity measurement scale, a significant correlation was found between subjective health and noise exposure in the noise-sensitive group, while no significant correlation was observed in the insensitive group. These results suggest that the adverse health effects may exist especially in the sensitive group. Application of the other two noise sensitivity measurement scales showed no significant relationship either in the sensitive group or in the insensitive group. The WNS-6B would have greater advantage for detecting adverse health effects than the other scales. Furthermore, the primary cause of the adverse health effect was investigated. The results of the analysis indicated that the adverse health effects were mainly caused by the sleep disturbance and were not caused by hearing interference.
ABSTRACT
Effects of noise on the secretion of salivary chromogranin A (CgA), which is considered to be a substitute measure of catecholamines, were investigated in a laboratory experiment. This study included 20 male subjects with normal hearing; their ages ranged from 21 to 24 years. Prior to the experiment, the subjects were asked to answer a questionnaire containing the 28-item General Health Questionnaire (GHQ-28) and Weinstein's noise sensitivity scale. White noise at 90 dB was presented to the subjects for 15 min with 15-minute-rest periods before and after noise exposure. It was shown that salivary CgA levels increased significantly during noise exposure and decreased immediately after it (Friedman's test, p = 0.001, two tailed). This result suggests that salivary CgA can be used to measure the stress response to noise. Furthermore, individual differences in the change in salivary CgA levels were discussed in relation to the subjective responses of the participants to the questionnaire. Some subjects showed prolonged elevation in the salivary CgA levels and the others showed immediate recovery or no effects. These individual differences correlated with the score on the somatic symptoms in GHQ-28; this implies that the score on the somatic symptoms in GHQ-28 could be a measure of physiological sensitivity to noise.