Exploring the relationship between noise sensitivity, annoyance and health-related quality of life in a sample of adults exposed to environmental noise.

Abstract

The relationship between environmental noise and health is poorly understood but of fundamental importance to public health. This study estimated the relationship between noise sensitivity, noise annoyance and health-related quality of life in a sample of adults residing close to the Auckland International Airport, New Zealand. A small sample (n = 105) completed surveys measuring noise sensitivity, noise annoyance, and quality of life. Noise sensitivity was associated with health-related quality of life; annoyance and sleep disturbance mediated the effects of noise sensitivity on health.

Full text

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Int. J. Environ. Res. Public Health 2010, 7, 3579-3594; doi:10.3390/ijerph7103580

International Journal of
Environmental Research and
Public Health
ISSN 1660-4601
www.mdpi.com/journal/ijerph
Article
Exploring the Relationship between Noise Sensitivity,
Annoyance and Health-Related Quality of Life in a Sample
of Adults Exposed to Environmental Noise
Daniel Shepherd 1,*, David Welch 2, Kim N. Dirks 2 and Renata Mathews 1
1 Auckland University of Technology, Private Bag 92006, Auckland, 1142 New Zealand;
E-Mail: renmat01@aut.ac.nz
2 University of Auckland, Private Bag 92019, Auckland 1142, New Zealand;
E-Mails: d.welch@auckland.ac.nz (D.W.); k.dirks@auckland.ac.nz (K.N.D.)
* Author to whom correspondence should be addressed; E-Mail: daniel.shepherd@aut.ac.nz;
Tel.: +64-9-921-9999; Fax: +64-9-921-9780.
Received: 19 August 2010; in revised form: 30 August 2010 / Accepted: 28 September 2010 /
Published: 11 October 2010

Abstract: The relationship between environmental noise and health is poorly understood
but of fundamental importance to public health. This study estimated the relationship
between noise sensitivity, noise annoyance and health-related quality of life in a sample of
adults residing close to the Auckland International Airport, New Zealand. A small sample
(n = 105) completed surveys measuring noise sensitivity, noise annoyance, and quality of
life. Noise sensitivity was associated with health-related quality of life; annoyance and
sleep disturbance mediated the effects of noise sensitivity on health.
Keywords: noise; annoyance; noise sensitivity; health-related quality of life

Abbreviation
HRQOL = Health Related Quality of Life
OPEN ACCESS

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1. Introduction
Health is multifaceted and encompasses not only disease and infirmity but also wellbeing [1].
Numerous factors interact to influence health and wellbeing, including biological (e.g., genetic
makeup), lifestyle (e.g., diet), and environmental (e.g., air pollution) factors. Noise, defined at the
psychological level of description as an unwanted sound, is increasingly being targeted as an
environmental factor negatively impacting health. In some contexts noise can elicit annoyance or
disrupt sleep in a manner detrimental to health, though the relationship between noise and health has
yet to be satisfactorily elucidated [2-4]. Noise standards emphasize noise level as the primary factor in
noise-induced health deficits, however, laboratory [5] and epidemiological (e.g., [6]) findings are
increasingly challenging this stimulus-orientated approach, and have instead sought to uncover factors
associated with the listener that predict health risk (for reviews see [7,8]).
Figure 1 is a schematic summarizing the relationship between noise and health. Two pathways are
evident, the physical (dashed line) and non-physical (solid line) effects of noise. The physical effects
of noise describe those noise-induced health deficits that are associated with sound level and
frequency, with Noise-Induced Hearing Loss (NIHL) being an example. Health deficits incurred along
this pathway may involve either wanted sound (e.g., attending a rock concert) or unwanted noise (e.g.,
working with loud equipment). The non-physical effects of noise are those which are mediated by
psychological or psychophysiological processes.
Figure 1. Model detailing how noise might compromise health. The dashed lines indicate
the physical effects of noise, which include Noise Induced Hearing Loss (NIHL), while the
solid lines represent the non-physical effects of noise. The box labeled “moderating
factors” represents the cumulative effect of traits, contextual factors, and noise parameters
(e.g., amplitude modulation). Annoyance and sleep disruption act as mediators
between predisposing factors and secondary health effects (e.g., health-related quality of
life or disease).

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There is general agreement in the literature that annoyance and sleep disruptions are the likely
mediators of noise-induced health deficits (e.g., [3,6]). However, the relative contribution of noise
parameters, personal characteristics, and contextual factors has yet to be determined. In relation to
annoyance, the literature indicates that only 10 to 15 percent of the variability in ratings can be
explained by noise level, arguing against the use of dose-response relationships as the sole basis for
noise standards. The remaining variability is likely to be explained by a collection of interacting traits
and contextual factors (viz moderating factors in Figure 1) including age [9], noise source and attitude
to the noise source [10,11], personality [12,13], mental functioning [4], time of day [14] and noise
sensitivity [15,16].
Noise sensitivity, considered a stable personality trait that is relatively invariant across noise
level [17], is a strong predictor of noise annoyance [15,18,19], and has been correlated with sleep
quality [3,20,21]. Stansfeld [15] described two key characteristics of noise sensitive individuals. First,
they are more likely to pay attention to sound and evaluate it negatively (e.g., as threatening or
annoying) and second, they have stronger emotional reactions to noise, and consequently, greater
difficulty habituating. Noise sensitivity has a large impact on noise annoyance ratings, lowering
annoyance thresholds by up to 10 dB [18], and a study of individuals exposed to low frequency noise
in the workplace showed noise sensitive individuals were more annoyed by a low frequency noise than
a broadband reference noise, while noise-resistant subjects reported that both noises were equally
annoying [22]. However, while there is a strong correlation between noise sensitivity and annoyance,
the correlation between noise sensitivity and noise level is weak, echoing the marginal relationship
found between noise annoyance and noise level [3,7].
In this paper, we report data collected from individuals living in the vicinity of Auckland Airport,
New Zealand’s largest and most active airport. The survey area is designated a high aircraft noise area
exposed to average outdoor noise levels between 60 and 65 dBA LDN. Consistent with the mode of
transport effect [23], aviation noise is rated as more annoying than road traffic or rail
noise [24], and we selected this area due to the presence of multiple sources of potentially annoying
noise including road, rail, and neighborhood noise. In assessing the heath impacts of noise, a variety of
outcome measures have been reported in the literature, including annoyance, sleep disturbance,
cardiovascular disease, and wellbeing. One approach to health assessment involves a subjective
appraisal of Health-Related Quality of Life (HRQOL), using tools measuring health satisfaction,
irrespective of objective health status. The WHO [25] reports that noise-induced annoyance and sleep
disturbance can, when chronic, compromise positive wellbeing and quality of life. Dratva et al. [26]
using the Short Form (SF36) health survey, reported a negative relationship between annoyance and
HRQOL in relation to road traffic noise. Published literature reviews indicate that HRQOL would be
expected to co-vary more with annoyance than with objective noise measurements [7,8,27]. On this
basis, we measured noise annoyance and HRQOL in a confined residential area exposed to constant
levels of aviation noise. In accordance with the findings of Dratva et al. [26], negative correlations
would be expected between HRQOL subscales and noise annoyance. Our main aim, however, is to
further evaluate the model presented in Figure 1, specifically the relationship between noise sensitivity
and health, and the mediating effects of annoyance and sleep. The interest in noise sensitivity arises
due to an increasing number of studies indicating that noise sensitivity is the dominant non-acoustical
influence of annoyance and sleep disturbance [3,28,29]. Furthermore, other studies have hinted that

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annoyance may be a mediating variable between noise sensitivity and mental health (e.g., [4]), though
this relationship has yet to be conclusively demonstrated [16,27].
2. Methods
2.1. Participants
The participants were 105 adults residing in a cluster of relatively homogenous housing
approximately 2.5 kilometres east of Auckland Airport’s main runway. According to the New Zealand
deprivation scores index [30] this area is ranked 9, where deprivation scores range from 1 (least
deprived) to 10 (most deprived) and are calculated using census data corresponding to geographical
areas containing a median of 90 people. The region in which Auckland Airport is located has the
highest number of decile 9 and 10 (i.e., most deprived) areas in New Zealand [30]. The sample area is
designated a high aircraft noise area exposed to average outdoor noise levels between 60 and 65
LDN [31]. The demographic profile of the sample is displayed in Table 1.
Table 1. Demographic characteristics of participants (n = 105).
Variable
Sex


Age







Ethnicity




Education



Occupation






Total
Category Number
25
72
8
5
9
18
14
28
13
17
1
51
20
12
10
12
59
25
20
1
49
22
7
5
2
9
11
105
Percent
23.8
68.6
7.6
4.8
8.6
17.1
13.3
26.7
12.4
16.2
1.0
48.6
19.0
11.4
9.5
11.4
56.2
23.8
19.0
1.0
46.7
21.0
6.7
4.8
1.9
8.6
10.5
100
Male
Female
Unspecified
18–20
21–29
30–39
40–49
50–59
60–69
70+
Unspecified
European
Maori
Pacific
Asian
Unspecified
High School
Technical
University
Unspecified
Employed
Retired/Sick
Student
Unemployed
On leave
Housewife
Other

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2.2. Instruments
In addition to items requesting demographic information, the survey contained three self-report
assessments, providing measures of HRQOL, noise annoyance, and noise sensitivity. Participants were
asked to make their ratings with respect to the previous two weeks. Health-related quality of life was
assessed using the World Health Organization Quality of Life (short-form) scale, the
WHOQOL-BREF. The WHO ([32], p. 1404) defines quality of life as: “an individual’s perception of
their position in life in the context of the culture and value systems in which they live and in relation to
their goals, expectations, standards and concerns. It is a broad ranging concept affected in a complex
way by the person’s physical health, psychological state, personal beliefs, social relationships and their
relationship to salient features of their environment”.
Quality of life, as defined above, is a multifaceted concept, and thus the WHOQOL-BREF produces
a descriptive multi-dimensional profile of HRQOL, not a single index. The WHOQOL-BREF consists
of 26 items divided into four domains: physical health (7 items), psychological wellbeing (6 items),
social relationships (3 items), and environmental factors (8 items). There are two additional items
probing overall quality of life and self-rated health. All 26 items in the WHOQOL-BREF are rated on
a five point Likert-type scale. A low score on any domain or item equates to negative evaluations of
that aspect of life, while a high score indicates a positive evaluation. The BREF is well suited to public
health use, and the inclusion of environmental items extends the WHOQOL-BREF beyond traditional
HRQOL measures which lack such perspective [33]. The WHOQOL-BREF has excellent reliability
and validity [34] and the advantage of adopting a transcultural approach to QOL [34].
Noise sensitivity was estimated using the Noise Sensitivity Questionnaire (NOISEQ) scale [35]
which measures global noise sensitivity as well as sensitivity for different domains of everyday life:
leisure, work, sleep, communication, and habitation. The 35 NOISEQ items were adapted from the
Weinstein Sensitivity Scale and Fragebogen zur Erfassung der Indiviuellen Larmempfindlichkeit (the
Individual Questionnaire of Noise Sensitivity), and reformulated to increase face validity [35]. Each item
asks the respondent to indicate their degree of agreement to statements about their responses to noise
using a five point Likert-type scale, which we modified from the original 4-point NOISEQ scales [35].
Global noise sensitivity is computed as the average of the leisure, work, habitation, communication
and sleep subscales, with higher means indicating greater sensitivity. The work, sleep and
communication subscales have been reported to be sufficiently reliable, while the leisure and
habitation subscales not nearly so [35,36].
Susceptibility to noise annoyance was assessed using a 12-item questionnaire developed as a
composite of items: 5 items were based on Kroesen et al. [37] and focused on annoyance due to
aviation noise, and 7 items were based on Thorne [38] and assessed annoyance due to other sources of
neighborhood noise. Preliminary assessment using Cronbach’s alpha suggested that it was appropriate
to combine these items in that the overall alpha was >0.9 and all item-total correlations were >0.4. All
12 items were standardized and summed to create a General Noise Annoyance scale.