Subjective ratings of health status and railway noise

Journal of Sound and Wbration (1988) 127(3), 593-598

SUBJECTIVE RATINGS OF HEALTH STATUS AND RAILWAY NOISE T. YOSHIDA

Department of Architectural Hygiene Engineering and Housing, 7he Institute of Atblic Health, 4-6-1, Shirokanedai, Minato-ku, Tokyo, 108 Japan AND

S. NAKAMURA Department of Noise, The Tokyo Metropolitan Research Institute for Environmental Rotection, l-7-5, Shinsuna, Koto-ku, Tokyo, 136 Japan (Received 15 July 1988) This study ~8s aimed at investigating effects of railway noise on subjective ratings of state of health and at clarifying the meaning of subjective ratings of health status in relation to objective disturbances due to noise. An attempt was also made to arrive at a noise level threshold according to subjective ratings of health and inhabitants’ responses to questions concerning disturbance due to noise. The inquiry was conducted among married women at 15 sites in Tokyo. Subjective ratings of inhabitants’ health were interpreted by age, noise level, occupation, husbands’ occupation and numbers of railway tracks. Greater age and high levels of noise increased reports of ill-health, and both factors had linear relations to the estimated values of the health status of the inhabitants. Annoyance showed no relation to subjective ratings of health status, whereas awakening, irritation and physical symptoms showed close relations to health. A noise level of 70 dB(A) in L,,. is suggested as a noise level threshold, after which increases in reports of ill-health and high disturbance accelerate. 1. INTRODUCTION Noise can cause annoyance and interferes with daily activities, and could thus generally be believed to lead to health disorders. Much research has been conducted on a possible increase of cardiovascular disease, nervous disorders and gastrointestinal disease in rather seriously noise-disturbed areas [l-4]. Evidence is gathering that noise, not even at extremely high levels, might increase ill-health interpreted through subjective ratings of states of health. This study was aimed at investigating effects of noise on the health of the inhabitants of residential areas located near railway lines in Tokyo. Data was collected on subjeotive ratings of the state of heath and objective disturbances of the inhabitants due to the railway noise. Furthermore, it was aimeed at obtaining a noise level threshold through subjective rating of health and inhabitants’ responses to noise disturbance. 2. METHODS Fifteen sites in Tokyo were investigated. Each site had an area of about 2 ha along railway lines. The sites were selected according to particular fac%ors:building density, numbers of railway tracks, structure of railways and number of trains passing through per day. The inquiry was conducted among 1123 married women, and &a for 830 were 593 0022-460X/ 88/240593 +06 $03.00/O

@ 1988 Academic Press Limited

594

T.

YOSHIDAAND

S.-I.

NAKAMURA

available for analysis. Information was gathered on age, occupation, size of family, length of residence and husbands’ occupation. Noise levels were estimated in Ldn (dB(A), day and night sound level). Table 1 shows the main questions concerning feelings of “annoyance”, “disturbance as a whole” and “dissatisfaction with noise environment”, and of objective disturbance in terms of speech interference (listening to media broadcasts, conversation and telephoning), sleep disturbance (awakening, difficulty in getting to sleep), psychological disturbance (irritation, being startled, difficulty in thinking or reading, difficulty in relaxing), physical symptoms (gastroenterological disorder, tinnitus or earache, headache or feeling heavy in the head, heart palpitation). TABLE 1 Questions on disturbances due to noise

General feeling

Disturbance as a whole Annoyance Dissatisfaction with noise environment

Speech interfetence

Listening to TV Telephoning Conversation

Sleep disturbance

Awakening Difficulty in getting to sleep

Psychological disturbance

Irritation Startle reaction Difficulty in thinking or reading Difficulty in relaxing

Physical symptoms

Gastroenterological disorder Tinnitus or earache Headache or feeling heavy in the head Palpitation

3. RESULTS Figure 1 shows the estimated values for age, noise levels, occupation, numbers of railways tracks and husbands’ occupation. These were selected by analysis with Hayashi’s quantification method II [5,6]. This method has been popular in Japan for analyzing categorical data from questionnaires which correspond in meaning to a multidimensional discrimination function to all dummy variables [5]. The method was introduced by Y. Ando in the Journal of Sound and Vibration [6]. In Figure 1, estimated plus values of the state of health indicate trends toward ill-health, while estimated minus values of state of health indicate trends toward good health. Zero of estimated values of state of health is the average of estimated values of health status for all the women. The far right side of the figure indicates averages of the estimated values of health status for each group of inhabitants demonstrating ill-health, normal health and good health. The figure demonstrates that greater age and higher levels of noise increased ill-health. Noise levels (L) were highly related to estimated values of health status (EVHS) in a regression given by EVHS = -1.60 + 0*0305L (r = 0.975). Age (A) was also highly related to the estimated values of health status in a regression given by EVHS = -2*31+0*0454A (r = 0.984). As regards occupational categories, “full-time workers” indicated a trend toward good health,

HEALTH

STATE

AND

RAILWAY

595

NOISE

Ill-health

_ No occupation - Pairsof - Professionals No occupation double tracks _____.._________,.__________,____ _ __._._Normal health - Wness. Single or - double tracks Ez$rcial industrial workers

- Part-timers

- EVHS=

I

I

I

I

50

60

70

health1

+0.0454 A

17, 20

Noise levels dB(A) of L,, [LI

Figure 1. Estimated inhabitants’ health.

Good

- Labourers

-1.60 i0.0305L

40

or

30

,

,

,

,

40

50

60

70

I

1 Occupation

Age (years) [Al

values

of health

status

for

main

factors

used

Tracks of railways

to interpret

Husbands’ occupation

subjective

Health status (averages of EVHS)

ratings

of

whereas “no occupation” indicated a trend toward ill-health. An analysis of husbands’ occupation demonstrated that “no occupation” and “professionals” indicated a trend toward ill-health, while “labourers” showed a tendency toward good health. In respect to railway tracks, “single track or double tracks” were more indicative of good health, while “two pairs of tracks” more often were related to ill-health. Table 2 shows the results of the .chi-square tests performed to examine independence between subjective ratings of health status and answers to each question on objective disturbances. It also shows the proportions (percentages) of ill-health among the “highly disturbed” respondents for each question on disturbances. The definitions of the “highly disturbed” respondents are indicated in the second column of this table. The results showed that annoyance had no relation to state of health, while awakening, irritation, gastroenterological disorders, headache or feeling heavy in the head and heart palpitation had very close relations to health status (p
596

T. YOSHIDA

AND S.-l. NAKAMURA TABLE 2

Relation between subjective state of health and each question on objective disturbances

Questions on disturbance due to noise

Definition of “highly disturbed” (Scale points)

Percentages of ill-health responses among “highly disturbed” respondents

6+7 (7)

13.0

0.04

4

(4)

13.6

0.89

4+5 (5) 4 (4)

16.4 18.5

4.23* 4.34*

4+5 (5) 4+5 (5)

36.4 31.6

4.74* 6*14*

4+5 (5) 4+5 (5)

20.3 33.3

6*16* 8*42**

4-1-5 (5) 4+5 (5) 4+5 (5)

36.8 57.1 66.7

10.32** 10.67*** 13*45***

4+5 (5)

26.7

13*83***

4+5 (5)

62.5

16.45***

4+5 (5) 4+5 (5) 4+5 (5)

71.4 44.0 44.8

19*96*** 24.52*** 30*68***

Annoyance Dissatisfaction with noise environment Interference with listening to TV General disturbance Difficulty in thinking/reading Difficulty in relaxing Interference with telephoning Startle reaction Difficulty in getting to sleep Earache or tinnitus Palpitation Interference with conversation Headache or feeling heavy in the head Gastroenterological disorder Irritation Awakening * p co.05; **, p-C0.01;

***,

Chi-square test (d.f. = 1)

p co4o1.

close relations to noise levels and that noise levels above 50 dB(A) increased the proportion of highly disturbed respondents for disturbance as a whole and annoyance. Noise above 60 dB(A) also clearly increased the proportion of highly disturbed respondents for speech interference. Furthermore, noise above 60 dB( A) increased highly disturbed respondents in the categories of sleep disturbance, psychological disturbance and physical symptoms. Noise levels above 70 dB(A) especially accelerated the increase of highly disturbed respondents in terms of sleep disturbance, psychological disturbance and physical symptoms. 4. DISCUSSION The correlation ratio was rather low (r = O-305) in the analysis by the qualification method. This means that health status can be affected by other factors not explored in this survey. Nevertheless, the partial correlation for the factor of noise levels was rather comparable to the partial correlation for the factor of age. Because the factor of age is generally considered to be of importance for ill-health, noise levels would lead to ill-health among older people. In fact, the results as shown in Figure 1 demonstrated that higher levels of noise increased ill-health. The noise level at which the categories of normal health and ill-health could be separated corresponded to 70 dB(A) according to the results of the analysis by the quantification method (Figure l), and noise above 70 dB(A)

597

HEALTH STATE AND RAILWAY NOISE TABLE 3

Noise levels vs. proportions

(%) of ill-health and highly disturbed

Noise levels, Ldn (dB(A)) Disturbance as a whole Annoyance TV listening Telephone conversation Conversation Getting to sleep Awakening Irritation Startle reaction Reading and thinking Relaxing Gastroenterological disorder Tinnitus and earache Headache and heavy head Palpitation Ill-health

respondents

30-49

50-59

60-69

70-79

14.8 4.0 1.5 0.3 0.3 0.3 0.0 0.3 0.3 0.0 0.3 0.0 0.0 0.6 0.0

34.8 22.1 13.4 4.8 2.8 0.3 1.7 1.7 1.0 0.0 0.7 0.0 0.6 0.6 0.0

62.8 48.7 43.6 23.1 19.2 5.1 8.3 5.8 4.5 1.9 3.2 1.3 1.3 1.3 0.6

82.8 58.6 58.6 48.3 36.2 15.5 19.0 17.2 17.2 13.8 19.0 8.6 6.9 8.6 8.6

6.8

13.4

13.5

19.0

accelerated the increase of the proportions of ill-health and highly disturbed respondents (Table 3). Therefore, a noise level threshold above which an increase in ill-health accelerates would be considered to be 70 dB(A) in Ldn. 5. CONCLUSIONS It may thus be concluded

that (1) greater age and higher noise levels increased

ill-health,

(2) annoyance did not show a relation to subjective ratings of health status, whereas awakening, irritation and physical symptoms indicated close relations, and (3) 70 dB(A) (&,,) seems to be a noise level threshold after which there is an increase of ill-health and highly disturbed respondents. ACKNOWLEDGMENTS As regards subjective ratings of state of health, the authors reanalyzed data from “Community Responses to Noise in Near-Area of Railways”, a study carried out by a committee comprised of Y. Osada (Chairman), A. Tamura, T. Yoshida and T. Mochizuki (Management), and S. Nakamura, N. Imaizumi and Y. Uehara of The Tokyo Metropolitan Research Institute for Environmental Protection (TMRIEP) in 1983. The authors wish to acknowledge all members of this project, the results of which were reported by S. Nakamura [7] in terms of a comparison of noise measurement among mean levels of peaks, L, and Ldnfor evaluating responses to annoyance and disturbances due to railway noise. REFERENCES 1. A. TARNOFQLSKY, D. J. HAND, S. M. BARKER and L. M. JENKINS 1980 Proceedings of the 3rd International Congress on Noise as a Public Health Problem, ASHA Report 10, 588-593. Aircraft noise, annoyance,

and mental health; a psychiatric viewpoint.

598

T. YOSHIDA AND

S.-I.

NAKAMURA

2. P. KNIPSCHILD 1980 Proceedings of the 3rd International Congress on Noise as a Public Health Problem, ASHA Report 10,238-287. Aircraft noise and hypertension. 3. E. GRANDJEAN, P. GRAF, A. LAUBER, H. P. MEIER and R. MULLER 1976 Proceedings of INTER-NOISE ‘76, 85-90. Survey on the effects of aircraft noise around three civil airports in Switzerland. 4. J. FRANCOB 1980 Proceedings of the 3rd International Congress on Noise as a Public Health Problem, ASHA Report 10,594-599. Aircraft noise, annoyance, and personal characteristics. 5. T. KOMAZAWA 1982 Quantijcation Methods and Data Analyses. Tokyo: Asakura-shoten. (In Japanese.) 6. Y. ANDO and H. HA-ITORI 1973 Journal ofSound and Vibration 27, 101-110. Statistical studies on the effects of intense noise during human fetal life. 7. S. NAKAMURA 1985 Noise Control of ZNCE JAPAN 9(6), 314-319. Community response of noise in near-area of railway (In Japanese).