Adverse effects of environmental noise on health: An interdisciplinary approach

Environment International, Vol. 16, pp. 437-445, 1990 0160-4120/90 $3.00 +.00 Printed in the U.S.A. All fights reserved. ~ t O1990 Pergamon Press plc

ADVERSE EFFECTS OF ENVIRONMENTAL NOISE ON HEALTH: AN INTERDISCIPLINARY APPROACH

M. P. J. Pulles, W. Biesiot, and R. Stewart Center for Energy and Environmental Studies, State University of Groningen, 9700 AB Groningen, The Nethedands

E18906-182M (Received 16 June 1989; accepted 20 January 1990)

A model, including psychological constructs (e.g., coping and control), was developed to predict adverse health effects of environmental noise. To evaluate this model, a combined research strategy was adopted, including a questionnaire administered to about 2000 subjects, a medical examination of a subset of about 830 subjects, and a laboratory experiment with a subset of 24 subjects. The subjects were in every day life exposed to varying levels of military aircraft or road traffic noise. No significant relation between noise level and blood pressure was observed in this survey. Subjective health and annoyance related variables however showed a dependence upon the level of environmental noise. Subjects perceiving an internal locus of control reported fewer complaints compared to those perceiving an external locus of control. The difference, however, is independent of the noise level. Subjects exhibiting a coping style based upon avoidance, showed a higher noise sensitivity compared to those with other coping styles.

INTRODUCTION

Background of the study

There exists much conflicting and confusing evidence on the question of whether or not environmental noise induces non-auditory physiological health effects in people suffering from this environmental stressor. Some studies report a significant increase of mean blood pressure in areas with a higher level of environmental noise, while other studies could not detect such influences. In the area of self-reported health effects and annoyance, rather low correlations between these variables and the level of environmental noise have been reported (see Cohen and Weinstein 1981; Kryter 1985 for recent reviews).

This study concentrated on the relationship between environmental noise and both objectively mea-

surable health variables like blood pressure, and subjective health variables. In a combined psychological and medical survey of subjects living in more or less noisy environments, evidence was gathered in this field. In addition to this survey, 24 subjects were invited to participate in a series of laboratory experiments designed to investigate in more detail hypo- theses and relations detected in the surveys. Details of the study were presented in a series of reports published earlier by the Dutch Ministry of Housing Physical Planning and the Environment: Altena 1987; Altena et al. 1988; Biesiot et al. 1988; Veldman 1988.

Theoretical considerations

As stated above, correlations normally found in studies that measure the effects of environmental noise, if any, are small. This finding can, in principle,

437

438 M.P.J. PuUes et al.

be interpreted in two ways: (1) either noise is only a very unimportant predictor of such health effects; or (2) other variables are influencing the hypothesized relations.

This study assumed the latter. The variables that may influence the relation between noise and health are supposed to be connected to the (physiological and/or psychological) processes that determine whether or not sounds, present in the environment, are regarded as being noisy.

The present research project was based upon the hypothesis that concepts used in biological and psychological stress theories played an important role in the noise-induced non-auditory health effects. This hypothesis was presented schematically in the model of Fig. 1. It was assumed that the presence of environmental noise itself was not enough to explain the occurrence of health effects. An individual might have judged the noise as being unwanted, threatening or annoying. The outcome of this appraisal process then might have induced the health effects under study. The appraisal may have been dependent upon the perceived locus of control and the available coping strategies of the individual (11 ... In in Fig. 1). Apart from this risk factors (kl . . k i n ) may have been

present, which also partly explain the observed health effects.

SAMPLES AND METHODS

Noise sources and population studied

It is generally assumed that different types of environmental noise may induce different effects. In this study, therefore, two sources of environmental noise were used: military aircraft noise (around the military airbases Leeuwarden and Twenthe) and road traffic noise (cities of Amsterdam and Groningen). At each of the four locations a sample was drawn, consisting of about 500 inhabitants aged between 20 and 55 years and living at different outdoor noise levels as indicated in Fig. 2. Noise levels (LAeq) were calculated from aircraft movements and traffic den- sitics and expressed as Kosten Eenheden (KE, the Dutch variety of the Noise and Number Index), and dB(A) respectively. Caution should be used in inter- preting Fig. 2. It would be a mistake to assume that 56 KE is comparable to 71 dB(A).

The sample drawn was representative of the healthy Dutch population, age 20 through 55, frequently at home during working days, and living in areas ex-

/nd/wduat c h a r a o t e r / s t / c s

copzng s t ra t e g / e s c o n t r o l p e r c e p t /on

Fig. I. Schematic representation of the relation between environmental noise and health, and the role of coping strategies and perceived locus of control (Iz..l,). Health effects might be induced by individual characteristics (k1..k,) as well.

Health effects of environmental noise 439

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Fig. 2. Design of the field surveys in this study. About 2000 subjects filled out the psychological questionnaires. A subset of 830 subjects was also medically examined.

posed to different levels of aircraft noise or road traffic noise respectively.

Psychological field survey

In the psychological field survey, questionnaires were presented to the subjects by trained interview- ers. The interview took about 1.5 h to complete. The questionnaire contained, apart from the usual ques- tions about demographic characteristics (age, sex, socioeconomic status, and the like), a number of multi-item scales as described by van Kamp (1986). These scales measure annoyance, disturbance and stress-feelings due to noise, subjective health (Hopkins Symptom Checklist , Derogatis et al. 1974), sleep quality (Groningen Sleep Quality List, Mulder-Hajonides van der Meulen et al. 1980), coping strategies, and perceived locus of control.

The Kosten Eenheid was defined such that the averaged activity disturbance score, as defined by Bitter and Schwager (1964) was numerically equal to this unit. Fig. 3 shows the findings in our samples.

Fig. 3 shows that the activity disturbance score in the aircraft noise sample was higher than expected from the definition of the Kosten Eenheid. This might indicate that the actual flight paths of the aircraft differed from the prescribed ones as used in

the calculations. An alternative explanation is that military aircraft noise, as such, might be more annoying or disturbing than civil aircraft noise.

Comparison of the disturbance levels in both samples indicates that the levels of road traffic noise used in this survey were less disturbing than the levels of military aircraft noise.

Medical field survey

Preliminary analyses of the data of the psychological survey were used to select participants in the medical examination. About 27% of the participants indicated they were not prepared to participate in the medical examination. About 80 subjects were ex- cluded because they reported suffering from such diseases as coronary heart diseases, diabetes melitis, renal diseases, and the like. From about 1300 subjects invited to participate in the medical examination, 830 showed up. This subset of 830 did not differ significantly from the original sample of about 2000 subjects on any of the variables of the psychological survey, nor did the group that did not participate.

In the medical survey, which lasted about 15 rain, blood pressures were measured both upon entrance and just before the completion of the examination. A number of components in blood (ureum, creatinine, glu-

440 M.PJ. Pulles et al.

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Fig. 3. Averaged activity disturbance score (Bitter and Swager 1964) as a function of the level of military aircraft noise (left) or road traffic noise (right). The dashed line in the left graph gives the regression line that follows from the definition of the Kosten Benheid.

cose, hemoglobin, cholesterol, and HDL-cholesterol) were determined. These factors were used to determine the presence of renal diseases and isch- emic heart diseases. Moreover an electrocardiogram was recorded and coded using the Minnesota Code. Finally the weight and height of each subject were measured.

Laboratory experiments

A small group of 24 female participants (aged below 40, average 3 l) of the medical and psychological surveys was invited to participate in the laboratory experiments. Subjects were selected on the basis of their scores on coping and perceived control in a 2 × 2 design: effective vs. ineffective coping and external vs. internal locus of control. The experiment consisted of two identical series of task performance measurements, one in quiet, one in the presence of 80 dB(A) noise (a combination of the noise inside a bicycle factory and road and aircraft noise). A number of tasks was used as an indicator of different mental processes: selective attention, speed and ac- curacy, capacity and availability of short-term mem- ory, and vigilance. Physiological data col lected included: a continuous measurement of blood pressure, an electroencephalogram (EEG), secretion of catecholamines and cortisol; details were described by Veldman (1988) and Van Kamp (1986).

RESULTS

Effects of noise on blood pressure

Fig. 4 shows the results of stepwise multivariate linear regressions of blood pressure measurements. About 80% of the variance in blood pressure was not associated with any of the variables measured in the surveys. Part of this unexplained variance was prob- ably due to unpredictable changes in blood pressure itself. The first and second measurement of blood pressure (about 15 minutes apart) showed a covari- ancc of not more than 60 to 70%, indicating a 30 to 40% unpredictable change within these 15 minutes. This observation raises serious doubts about the representability of this type of data for blood pressure values as indicators of (long term) individual health.

In the first step of the analyses, individual characteristics were introduced into the equation. On_ly relative weight (quetelet index = weight/height z) age, and sex of the subject contribute significantly to the variance. In the second step, noise annoyance was introduced into the equation. Only in the diastolic blood pressure a detectable change in the amount of explained variance was found. The contribution, however, was not significant. Introduction of noise level in the third step does not change the amount of explained variance at all.

Since the correlation between relative weight and environmental noise levels or noise annoyance was low in this survey, we concluded that no significant


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Aircraft noise Road traffic noise Fig. 4. Variance of blood pressure in the aircraft noise sample (left) and the road traffic noise sample (right). The plots give covari-

ances calculated by means of stepwise multivariate regressions (BMDP program P2R). In the first step individual characteristics w e r e

introduced, followed in the second step by noise annoyance and noise level.

dependance of blood pressure upon environmental noise was present in this survey. Apparently noise- induced blood pressure changes are too small to be detected in a medical field survey with (two times) 400 subjects. In agreement with the conclusion of Thompson (1990) a survey with a much higher number of subjects might be needed (2000 to 4000 subjects).

Laboratory experiments No significant change of task performance associ-

ated with the presence of noise was detected in the laboratory experiments. Noise induced changes of blood pressure, however, were observed (Veldman 1990). This result was in agreement with the results reported by Tafalla et al. (1988). The changes in blood pressure in the laboratory occur on a com- pletely different time scale (minutes) as compared to the changes which can be detected in a field survey (long-term averaged changes).

Dimensions of health

In this research project the integral definition of health of the World Health Organization (WHO 1946) was adopted. Therefore, apart from blood pressure and other objectively measurable health variables, subjective health and annoyance variables were also

measured. In order to describe the approximately 20 variables measured in terms of health dimensions, a factor analyses on these variables was performed. Three distinct factors were found: (I) one factor predominantly associated with the

blood pressure measurements and relative weight (termed OBJECTIVE HEALTH);

(2) one factor associated with self-reported health (Hopkins Symptom Checklist) and sleep quality (termed SUBJECTIVE HEALTH);

(3) one factor associated with such variables as annoyance, disturbance and stress feelings due to noise (termed ANNOYANCE).

Fig. 5 shows the variables of the second and third factor in factor space. Variables of the first factor are perpendicular to the plane of the figure. The results were the same in both the aircraft noise and in the road traffic noise samples. This underlines the rele- vance of the factors found.

We concluded that the variety of health variables measured in the surveys can be interpreted as estima- tors of three independent dimensions of the concept of health: an objectively measurable (physiological) health factor, subjective health, and annoyance. In the following, these three factors are used.

442 M.P.J. Pulles et al.

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Fig. 5. Results of factor analyses on the health variables (ANNOYANCE and SUBJECTIVE HEALTH) measured in these surveys. A third factor (OBJECTIVE HEALTH) is perpendicular to the plane of the figure.

In agreement with the results of Fig. 4, no significant relation was detected between level of environmental noise and objective health. The other two factors however did show correlations with the level of noise exposure. Higher correlations were found if a subjective measure of the quality and the level of the noise was used. In the next section the influence of the psychological variables of the model in Fig. 1 upon these relations is discussed.

The influence of perceived locus of control

One of the variables that are supposed to be of influence upon the relationship between environmental noise and health is the amount of control the subject perceives to have over the noise source. Jones (1984) describes this perceived control as: "The per- sonality construct in question is that of locus of control ( .... ). This refers to the beliefs that individuals hold regarding the ways in which outcomes occur. These individuals who regard outcomes as attribu- table to others's actions are thought to have 'external' locus of control. An attribution to the individuals' adequacy or skills reflects an 'internal' locus of control." The locus of control was measured using a 4 item scale as described by van Kamp in Altena et al. (1988).

Fig. 6 presents the results of a comparison of the linear regressions between environmental noise and SUBJECTIVE HEALTH and ANNOYANCE in sub- samples having internal vs. external locus of control. From the analyses of Fig. 6, we observed that, in the case of the ANNOYANCE related health factor, a significant influence of the perceived locus of con-

trol was present. Subjects perceiving an external locus of control showed a higher score on the annoyance factor as compared to subjects perceiving an internal locus of control. The difference however was independent of the noise level. Apparently, the former group produced more complaints, but was not more noise sensitive. The SUBJECTIVE HEALTH factor showed no or only barely significant differences between both groups.

The influence of coping strategies

In the full report of this project Van Kamp (in Altena 1988) showed that three independent coping strategies can be discerned in the samples used in this study. These coping styles are: (1) an action directed coping style--closing the win- dow, filing complaints, protesting and the like; (2) a coping style consisting of developing comfort-

ing cognitions ("this noise is not the worst thing that can happen to me, a lot of things are more unpleas- ant"); and, (3) a coping style consisting of denial or avoidance of the stressful situation ("environmental noise? no problem, it does not bother me, I can easily live with it").

As was discussed by Biesiot et al. (1988), only the third coping style (avoidance) seems to significantly influence the relation between environmental noise and health variables. Fig. 7 presents the results of analyses analogous to those of Fig. 6, comparing subjects differing in the amount of avoidance in their coping strategies. From these analyses it was observed that significantly different regression lines


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Fig. 6. Comparison of linear regressions between levels of environmental noise and subjective health factors in subjects perceiving an external (full lines) vs. subjects perceiving an internal (dashed lines) locus of control in the aircraft (left) and road traffic noise sam-

ples respectively. A significant F-ratio (F > 5) indicates that the regression lines differ beyond doubt.

are found in subjects showing highly avoiding coping styles compared to subjects who showed a less avoiding coping style.

As expected, the avoiding strategy was associated with a higher level of complaints, both in the road traffic noise sample and in the aircraft noise sample. The differences in the aircraft noise sample are larger (F > 30) than those in the road traffic sample (F = 10.5).

As is observed from Fig. 7, in the aircraft noise sample the difference between the regression lines in ANNOYANCE was primarily due to a difference in slope of the lines. SUBJECTIVE HEALTH showed the same effect to a less pronounced extent. Appar- ently the group of subjects with a highly avoiding coping strategy was more sensitive to military aircraft noise than the group of subjects with less avoiding coping strategies. The road traffic noise sample did not show the same result. This might have been

due to the lower amount of annoyance and disturbance induced by the levels of road traffic noise used in these surveys as compared to the aircraft noise levels used (see Fig. 3).

DISCUSSION AND CONCLUSIONS

In a field survey amongst two times 400 subjects, no significant correlations between the level of environmental noise (military aircraft noise or road traffic noise) and objectively measurable health effects like blood pressure were detected. This was in agreement with the results presented by Thompson et al. (1990)--much larger surveys are necessary to detect such effects, if any.

Noise-induced changes in subjective health dimensions (SUBJECTIVE HEALTH and ANNOYANCE) were detected and showed dependence upon the perceived locus of control and on the coping strategy the

444 M.P.J. Pulles et al.

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Fig. 7. Comparison of linear regressions between levels of environmental noise and subjective health factors and in subjects having highly avoiding (full lines) vs. subjects having little avoiding (dashed lines) coping styles in the aircraft (left) and road traffic noise

samples respectively. A significant F-ratio (F > 5) indicates that the regression lines differ beyond doubt.

subject used. This means that psychological concepts from stress models are relevant to understanding the relationship between environmental noise and health.

Subjects perceiving to control the exposure to the environmental noise, showed a lower level of health complaints and annoyance as compared to subjects perceiving other persons to control the situation. Since the differences between both groups were independent of the noise level, no different noise sensitivity could be inferred. One possible explanation for this result may be that the fact of perceiving no control over the environmental noise made a subject com- plain more than those who perceived they had control. The opposite conclusion, however, may be equally valid--he or she who experienced subjective health effects, also perceived having no control over the nasty (noisy) things happening.

The coping strategies an individual has available, had a detectable influence upon the noise sensitivity

as measured by the regression line of noise level and SUBJECTIVE HEALTH--subjects who deny the adverse effects (avoidance coping style) showed a steeper increase of subjective health effects with the level of environmental noise. This coping style therefore can be regarded as being ineffective.

Although, in the field survey, no significant relationship was detected between environmental noise and blood pressure, such changes were present in the laboratory experiments. These results were interpreted in terms of a compensating effort theory--people invest a certain amount of (physiological) energy to prevent a decrease of the performance level due to the disturbing presence of noise. Apparently these short-term changes detected in the laboratory do not, if also present in every day life, result in higher averaged blood pressures detectable in a medical field survey with about 800 subjects.


A c k n o w l e d g m e n t ~ This paper is based upon a research project, financed by the Dutch Ministry of Housing, Physical Planning, and the Environment, and carried out at our institute by K. Ahena, W. Biesiot, N.E. van Brederode, I. van Kamp, T.R. Knottnerus, J.V. Lako, M.P.J. Pulles, R.E. Stewart and J.B.P. Veldman.

REFERENCES

Altena, K., ed. Theory and method of an interdisciplinary investi- gation into the effects of environmental noise on health, En- glish preface and introduction, Report No. GA-HR-03-O1. The Hague: Ministry of Housing, Physical Planning and the Envi- ronment; 1987.

Altena, K.; Biesiot, W.; van Brederode, N.E.; van Kamp, I.; Knottnerus, T.R.; Lako, J.V.; Pulles, M.P.J.; Stewart, R.E. En- vironmental noise and health, description of data, models and methods used, and the results of the epidemiological surveys. Report No. GA-DR-03-OI. The Hague: Ministry of Housing, Physical Planning and the Environment; 1988.

Bieslot , W.; Pulles, M.EJ.; Stewart, R.S. Environmental noise and health; Supplementary analyses and assessment of results. Report No. GA-DR-03-03. The Hague: Ministry of Housing, Physical Planning and the Environment; 1988.

Bitter, C.; Schwager; K.W. Enquire reacties bevolking op vliegtuiglawaal. IG-TNO deelrapport 3. Delft: TNO; 1964. (In Dutch).

Cohen, S.; Weinstein, N. Non auditory effects of noise on behavi- our and health. J. Social Issues 37:36-70; 1981.

Derogatis, L.R.; Lipman, L.S.; Rickels, K.; Uhlenhuth, U.E.H,; Covi, L. The Hopkins symptom checklist (HSCL): a self-report symptom inventory. Behav. Sci. 19:1-15; 1974.

Jones, D.M. Performance effects. In: Jones, D.M.; Chapman, A.J., ieds. Noise and society, Chichester: John Wiley & Sons; 1984.

Kryter, K.D. The effects of noise on man. New York: New York Academic Press; 1985.

Mulder-Hajonides van der Meulen, W.; Wijnberg, J.; Hollander I.; van den Hoofdakker, R. Measurement of sleep quality. Paper presented at the European sleep conference, Amsterdam, 1980. Psychiatric University Clinic, Groningen.

Tafalla, R.J.; Evans, G.W.; Chen, A. Noise and human performance: the potential role of effort. In: Berglond, B.; Berglund, U.; Karlsson, K.; LindvaL1, T., eds. Proc. 5th international congress on noise as a public health problem. Stockholm, Swe- den: Swedish Counsel for Building Research. 3:95-100; 1988.

Thompson, S.J.; Fideil,S. Feasibility of studying human health effects of aircraft noise in large populations. In: Berglund, B. and Lindvall, T., eds. Proc. 5th international congress on noise as a public health problem., 1988. Stockholm, Sweden: Swedish Council for Building Research. 4:363-371; 1990,

Van Kamp, I. Environmental noise and health: psychological as- pects in the relation between noise and health: choice and measurements of concepts. Groningen, The Netherlands: Cen- ter for Energy and Environmental Studies; 1986. (In Dutch).

Veldman, J.B.P. Effects of noise on performance and effort. Report No. GA-DR-03-02. The Hague: Ministry of Housing, Physical Planning and the Environment; 1988. (In Dutch).

WHO (World Health Organization). Constitutions of the World Health Organisation. Geneva, Switzerland: WHO; 1948.

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Adverse effects of environmental noise on health: An interdisciplinary approach