Perceptions of Aircraft Noise Exposure, Noise Sensitivity? Sleep Disturbance and Health: Results from the Bristol Noise, Sleep and Health Study

The aim of the present research was to examine associations between perceptions of noise exposure, noise sensitivity, sleep disturbance and health in an area where aircraft noise is not particularly prevalent (Bristol, UK). A questionnaire was mailed to a random community sample and 543 responses were received. This sample was found to be a representative sample of the general population. Preliminary analyses suggested that perceptions of aircraft noise while trying to sleep, noise sensitivity and noisedisturbed sleep were all having significant effects on subjective health. The effects of noise exposure and noise sensitivity were entirely due to neuroticism. However, sleep disturbance due to noise was still related to health even when negative affectivity was co-varied. This confirms results obtained with another sample and investigations of noise exposure in general. Further research is considering whether a similar pattern holds when exposure levels are higher. A longitudinal study is desirable to determine the causal relationships linking noise disturbed sleep and health. 1 INTRODUCTION Annoyance caused by noise is a major source of complaint to local environmental health offices. Indeed, it is an undisputed fact that people are annoyed by a wide range of external noise events. It is also clear that non-auditory factors such as noise sensitivity and attitudes to noise are important in determining the level of annoyance [1]. Subjective health and noise have been examined in a variety of ways. For example, there have been studies of noise and psychological symptoms both in the workplace [2] and general population [3]. Other research has examined noise and psychiatric morbidity in the community [4]. Noise annoyance is associated with noise level and with reporting of symptoms. What is unclear is the relationship between noise exposure, disturbed sleep, annoyance and noise sensitivity and psychiatric disturbance. Some simple relationships between these factors can be largely ruled out by earlier findings. For example, both noise and psychiatric disturbance are associated with annoyance, but it appears to be psychiatric morbidity influencing annoyance rather than the other way around [5]. There is evidence of both objective and subjective sleep disturbance by noise [6]. There is some evidence that noise effects on sleep may habituate over time, but research also suggests that small deficits may persist for years [7]. Noise exposure during sleep is considered to increase awakening or cause shifts from deeper to lighter sleep stages (see [8] for a review). Noise during the day may also reduce REM sleep [9] which shows that noise can influence sleep in several different ways. There has been specific interest in the effects of aircraft noise at night on sleep [10] and the present article reports data on this topic. The present research assesses the impact of community noise on sleep and on subjective reports of health [11]. Measures of noise sensitivity are recorded as are general noise annoyance and annoyance produced by specific noise exposures. The study from which this paper is derived was conducted in the Bristol area, to determine the general effects of noise on sleep and health. As such, it was not designed to enquire into Copyright SFA InterNoise 2000 2 aircraft noise effects specifically, but contained a number of relevant items, within the context of general noise. Bristol, although it has an airport and an aircraft manufacturing industry, is not regarded as a high aircraft-noise area; response patterns were expected to show a range, but with greater concentrations at the lower end of the spectrum. As such, it would provide a basis for comparison with areas around airports where aircraft noise might be seen as a contentious issue. 2 METHODOLOGY The study consisted of a postal survey. A questionnaire, with a covering letter, was mailed to 2,000 people, randomly selected from the electoral register for the Bristol area. A cutoff point of eight weeks for the return of questionnaires was decided. The questionnaire contained demographic questions, questions regarding lifestyle, sleep patterns, noise sensitivity [4], [12], perceptions of frequency and intensity of a range of noises, at various times of the day. In addition, two validated questionnaires were included: The General Health Questionnaire [13] and Eysenck’s Personality Inventory [14] for the measurement of negative affectivity. Further details of the study are given in Hayward [15]. 543 respondents completed questionnaires. Ages ranged from 20 to 98 years. There were 256 males and 287 females. The mean age for males was 52.1 years, for females, 47.2 years. Demographic data supplied by the respondents was compared with the 1991 Census data for the area, and the sample found to be a representative one. From the questionnaire data collected, variables of interest in a study pertaining to aircraft noise were identified, in order that analyses might be conducted. Aircraft noise exposure, noise sensitivity, health measures and sleep measures were all identified, and factor analyses were conducted for each of these groups of variables separately, in order to select the most appropriate variables to include in subsequent analyses.