Keio J. Med. 27: 69-88, 1978

PREVALENCE OF CHRONIC BRONCHITIS SYMPTOMS IN JAPAN

-A review of the nation-wide surveys on prevalence of pulmonary symptoms using standard questionnaire

TOSHIO TOYAMA* and JUN KAGAWA**

* Department of Preventive Medicine and Public Health , School of Medicine, Keio University, Tokyo, Japan ** Department of Public Health , School of Medicine, Tokai University, Kanagawa, Japan

(Received for Publication, October 28, 1978)

ABSTRACT

This paper reviewed prevalence rates of various pulmonary symptoms among 22,560 general population in 21 survey areas throughout Japan, 1965 1973, interviewed by health professions using standard questionnaire of Japa nese version of British Medical Research Council for chronic bronchits. Prime symptoms, persistent cough and phlegm were fairly low rates as compared to England and the U.S. studies. Their wide ranged rates may imply the pre valence of pumonary symptoms in Japan is not static, and cigarette smoking and rapid industrialization may be possible factors to altering the morbidity to comparable level of the Western countries in future. Sputum examination and pulmonary function tests were also discussed.

INTRODUCTION

The statistics of mortality and morbidity of the chronic non-specific lung diseases in Japan have been obscure because of lack their appropriate standard diagnostic criteria and being regarded as minor respiratory conditions, and until recently for chest physicians tuberculosis had been the greatest concern among other lung diseases. Furthermore in our National Health Insurance Scheme, chronic bronchitis is considered to be a low cost disease and thus reflected on doctors diagnostic habits. For instance the crude death rate for chronic bron chitis for all ages in 1963 in Japan was very low, 3.4, (Table 1) in contrast to

69 70 Toshio Toyama and Jun Kagawa

Table 1 Respiratory Disease Crude Death-Rates/10,0000, Both Sexes in All Ages, by Specified Cause in Japan

* WHO 1957 ** WHO 1968 *** not tabulated

119.0 for England Wales in the same year.1 Morbidity of chronic bronchitis had been almost unreliable until about 10 years ago because the disease was not re portable and there was no eligible epidemiological studies. The present study is reviewed excerpts from studies and surveys on pre valence of pulmonary symptoms among general population throughout Japan, carried out from 1965 to 1973 by individual researchers of university, local in stitutes of health and local health centers. All the surveys discussed here were done by interview techniques using the Japanese version of the British Medical Research Council's questionnaire of respiratory symptoms (1966). The inter views were made by physicians, epidemiologists and public health nurses. In a study abbreviated KI in this report, the 1960's version was used by author in 1965, which was first attempting of interview towards general population in a rural area in Japan. Because the interviews were carried out in different places (21 districts), by different interviewers, at different times (majority was done in winter and autumn seasons, and one in summer), and on different segment of general popu lation from farmers to white-collar employee in city, only a crude comparison without calculating any statistical significance is discussed here by merely dis playing mean prevalence rates and their ranges, minimum and maximum rates of various items of the pulmonary symptoms in the survey areas. Prevalence of Chronic Bronchitis Symptoms in Japan 71

OUTLINE OF THE SURVEYS AND THE SOURCES OF MATERIAL

In 25 surveys in 21 survey areas, 22.590 subjects were interviewed with the standard questionnaire as shown in Table 2. Seven surveys were done by individual researchers of universities or research institutes and 18 were carried out under the national programme by local health agencies with the aid of local medical schools. The population density of each district is listed for the con venience of urban-rural comparison. The type of district was cited from "The minryoku" (Resources of public welfare) by the Asahi Press.2 In 7 surveys total population sampling was made for 40 to 59 years of age and in 18 districts random sampling was done from the residence registry of general populations of the same age groups. Interviews were taken place at local health centers, citizen's halls and community centers. Home visits and letter communications afterwards filled the blank of the reasons for those unable to come. The response rates in the table included those cases. Three serial surveys were made in Kashima town (abbreviated K1, K2 and K3 in Table 2) in 1965, 1969 and 1973. The first survey was done in the agricultural period with entirely clean air and the second was at the beginning of construction of a large scaled industrial com plex. The third (K3) was of two years after when some large plants began to work. The sources of the original reports are listed on the end of this paper. It is regrettable that many reports adopted here, with three exceptions, were un official government publications furnished basic data for the purpose of area designation of the environmental health hazard compensation act.

PREVALENCE OF PULMONARY SYMPTOMS

1) Classification and definition of the respiratory symptoms

The symptoms classified here were based on the report of the BMRC's com mittee on the aetiology of chronic bronchitis3 and its instruction for the use of the questionnaire (1966),4 and referred also to many important studies published in the past, mainly in U.K. and the U.S.5-17,19,20 The symptom or combination of symptoms selected, and the coding of ques tions and their symptomatic implications are as follows :

Persistent cough: Grade 2 or "yes" to (Q 1.+3+5) and (Q 5), usually cough first thing in the morning, during the day or at night in the winter on most days for as much as three months each year. Table 2 Surveys of Prevalence of Pulmonary Symptoms in Japan, 1965-1978 Prevalence of Chronic Bronchitis Symptoms in Japan 93

Persitent phlegm : Grade 2 or "yes" to (Q 6+8+10) and (Q 10), usually bring up any phlegm from the chest first thing in the morning, during the day or at night in the winter or most days for as much as three months each year. Persistent cough and phlegm (PCP) : "yes" to (Q 1/3+5+6/8+10) and (Q 5+10) . Persistent cough and phlegm plus exacerbations or shortness of breath: "yes" to (Q 1/3+5+6/8+10+12bc and Q 5+10+12bc) or (Q 5+10+14b) , exacerbations of cough and phlegm lasting three weeks or more in the last three years, or CPC with dyspnoea. "Chronic bronchitis syndrome"4: "yes" to (Q 6+12b/c+4a ,b and "no" to Q 14c), winter morning phlegm, exacerbations of 3 weeks or more with more than one, and breathlessness grade 3.

2) Persistent cough, and persistent phlegm As shown in Table 3, both cough and phlegm in males are higher grade than in females in total, and age gradients exist. Prevalence of phlegm is much higher than cough in over all. In this table, rural and urban area was grouped by population density 1,000 per square kilometer. The difference of urban and rural mean prevalence of the symptoms is very remarkable, about twice in urban. Holland and Reid6 reported in their 1965's study in London that almost no rural urban difference as to these items of symptom was observed. Their U.K.'s rates (1965) seemed little higher than Japan. However, while the prevalence of phlegm grade 2 of male in U.K. country towns and London mail-van drivers ranged 15-19% for 40-49 years and 13.8-25.5% for 50-59 years, the present Japanese rates for males were 2.8-26.5% (40-49 years) and 3.3-30.2% (50-59 years) re spectively. These figures account for that there is no large difference in per sistent phlegm between Londoner and Japanese in some cities although the time of survey differs about 10 years. In the U.S. studies such as postal and transit workers in New York City,14 East coast telephone plants,18 and California telephone workers,16 the rates of persistent coughs and persistent phlegm"' were within the range of our present data.

3) Persistent cough and phlegm (PCP) Prevalence of PCP in the survey areas by sex and age, and rural-urban difference was shown in Figure 1. The difference of prevalences (Q 1/3+5+ 6/8+10) and (Q 5+10) is originated in persistency of symptoms in the morning or on the day (or at night), and in all the day, as described in MRC instruction Table 3 Prevalence (%) of Cough Grade 2 & Persistent Cough, and Phlegm Grade2 2 & Persistent Phlegm

* Numbers are BMRC questionnaire items . ** District: K 1 , K 2, A, AK, M, S 1, F 1, F 2, *** District: I , KI, T, C, 0, YO, N, MI, S 2, OM, Y, SAK, YO, TOY, KA, Prevalence of Chronic Bronchitis Symptoms in Japan 75

* 1/3+5+6/8+10 8 5+10

Fig. 1 Prevaolence (%) of Persistent Cough & Phlegm,

guide. Age gradient, higher rate in older age, and sex gradient, higher in male than female, were also observed. Regional difference of the PCP in terms of population density was also remarkable. A trend of higher prevalence was ob served in newly developing industrial regions. Overall rates of PCP (5+10) for males were considerably low ranging 1.7-17.9 (mean 7.7) for 40-49 years 76 Toshio Tovama and Jun Kagawa and 0.8-23.5 (mean 10.0) for 50-59 years. These figures are considerably lower than London (25.7% for 40-49 years and 38.7% for 50-59 years)' and U.K. country towns (24.0% and 18.9% respective)'18 and California workers (20.6 23.1% and 14.3-31.4% respectively). is However, to the prevalence of New York postal and transit workers14 (12.1-15.0% for 40-49 years 10.9-15.6% for 50-59 years), present Japanese rates are comparable. Considering prevalence of phlegm alone, Japanese general population and Anglo-American people fell more or less on the same level, but the prevalence of PCP for Japanese was generally lower, because their prevalence of cough was less. The reason might be of some cultural origin. It was noted that there was no significant changes in the prevalence between three serial surveys with four year interval each in Kashima area so far (Kl, K2 and K3), though the details are omitted to describe here.

4) PCP with exacerbations and dyspnoea

As shown in Table 4 and 5, all the prevalence of these symptom combination was also fairly low as compared with other Anglo-American results. Possible reasons for low grade of these items in Japan are conceivable as; relatively short period of history since abrupt industrialization occurred, factors of tobacco smoking habits, and other unknown factors.

5) Chronic bronchitis syndrome This syndrome, combination of morning phlegm in winter, exacerbations and dyspnoea, first adopted by the College of General Practioners in 1957,12 is shown in Table 6. In the British national survey, the prevalence of this syndrome for aged 40 and above was 8% for males and 3% for females, while in Japanese studies 3.8% (0.3-12.5) and 2.8% (0.7-8.6) respectively in 20 regions. In New York postal and transit worker's study, this prevalence was 3.3% for postmen and 1.8% for transit workers.

SMOKING HABITS AND PREVALENCE OF PULMONARY SYMPTOMS

Smoking habits and prevalence of pulmonary symptoms Smoking has been the most important determinant of the causation of chronic bronchitis. According to the report from the Japan Monopoly Corporation, dur ing the past 50 years tobacco consumption of Japanese increased five times (55,000,000 gr in 1923), and in 1970 about 80% of males and 10% of females had smoking habits, and daily consumption of cigarette per head was about 21 for male and 10 for female. The daily amount of cigarette has been increasing Table 4 Prevalence (%) of PCP + Exacerbations

* Numbers are BMRC questionnaire items . ** District: K 1 , K 2, A, AK, M, S 1, F 1, F 2, *** District: I , KI, T, C, 0, N, MI, S 2, OM, Y, SAK, TOY, KA, 78 Toshio Toyama and Jun Kagawa

Table 5 Prevalence (%) of PCP + Dyspnea and PCP + Exacerbations + Dyspnea

* Numbers are BMRC questionnaire items . ** District: I , T, C, 0, N, MI, S 2, OM, Y, *** District: K 1 , K 2, A, AK, M, S 1, F 1, F 2,

Table 6 Prevalence (%) of "Chronic Bronchitis Syndrome"* by Sex (Age 40<)

* Instructions for the use of the questionnaire on respiratory symptoms (1966) P. 16. ** Numbers are BMRC questionnaire items . *** District: K 1, K 2, A, AK , M, F 1, F 2, **** District: I , KI, T, C, 0, TO, N, MI, OM, Y, SAK, TOY, KA,

for recent five years in both sexes and the trend is steeper for females. The present report of the survey areas revealed that the rate of smoker by sex was well compatible with the report of the Monopoly Corperation ; in rural areas Prevalence of Chronic Bronchitis Symptoms in Japan 79

76.0% of males and 10.1% of females were smoker and 14.4% of males and 88.6% of females were non-smoker, and in urban areas 73.7% of males and 19.2% of females were smoker, and 13.5% of males and 78.1% of females were non-smoker. It should be noted that male-female ratio of smoker in rural area was 7.5/1, while 3.8/1 in urban areas (Table 7).

Table 7 Regional Difference of Male-Female Ratio of Smoker

The prevalence of phlegm Grade 2 and persistent phlegm for males accord ing to smoking category and rural-urban difference was shown in Table 8. Smok ing gradient ; the higher rate the heavier smoker, and higher rate of urban areas were distinct. Among New York postal workers14 the prevalence of persistent phlegm (Q 10) for non-smoker was 13.3% and mean value of the present report was 13.5%. However, there was a tendency of higher rate of heavy smoker in U.K. than that in Japan. Prevalence of PCP by smoking category for males is shown in Table 9. Table 10 shows comparison of persistent phlegm (Q 10) and PCP (Q 5 + 10) by never and present smokers for males. The prevalence increased as smoking amount increased and rural-urban gradient was also observed. The same tendency was seen in London and U.K. country town studiesC except their higher prevalence in heavier smokers. The prevalence of PCP of smoking category in New York14 and California16 studies fell roughly within the middle of Japan and U.K.

SPUTUM

Volume and character of morning sputum (expectoration 1 hour after rising) were examined in only six survey areas. This reflected difficulty of sputum collection in general population. About half number of the containers collected was nil of sputum volume, ranging 40.1-76.5%. Those who expectorated less than 2 cc were 34.0-48.9% for male and 20.7-30.4% for female, and 2 cc or more were 5.3-14.6% for male and 0.8-5.0% for female (Table 11). This sex difference Table 8 Prevalence (%) of Phlegm Grade 2 and Persistent Phlegm by Smoking Category (Males age 40-59)

* Number are BMRC questionnaire items . ** District: K 1 , K 2, K 3, A, AK, M, S 1, F 1, F 2, *** District: C , I, T, K, S 2, N, 0, MI, SAK, Y, KA, TOY, OM, Prevalence of Chronic Bronchitis Symptoms in Japan 81

Table 9 Prevalence (%) of PCP by Smoking Category (Males, age 40-59)

* Numbers are BMRC questionnaire items . ** District: K 1 , K 2, K 3, A, AK, M, F 1, F 2, *** District: C , I, T, N, 0, MI, SAK, Y, OM,

Table 10 Prevalence (%) of Pulmonary Symptoms by Smoking Habits AMales, age (40-59)

Number are BMRC questionnaire items. **District: K 1 K 2, K 3, A, AK, M, S 1, F 1, F 2, *** District: C , I, T, K, S 2, N, 0, MI, SA, Y, KA, TOY, OM,

might be chiefly due to smoking habits and socio-cultural factors. The same category was also higher in urban areas. Mucous and pulurent sputa were higher rate in urban areas than in rural areas. As Holland and Reid° have already demonstrated the similar evidence in their London studies, this may be due to the urban factors such as air pollution. 82 Toshio Toyama and Jun Kagawa

Table 11 Volume and Character of Morning 1 hr. Sputum

* No. of plastic container brought at interview.** M-Cucous MP-Muco-pulurent P-Pulurent *** Including M1, Ms of MRC definition of 1966. **** Including P1 , P2, P3 of MRC definition of 1966.

Pulmonary function tests

The pulmonary function tests of common ventilatory capacity were measured by five different instruments in the survey areas. As it is difficult to compare these results by different methods and lack of anthropometry, only regression curves of 1 second forced expiratory volume and percent FEVI,o by sex and age were figured (Figure 2 and 3). The lower percent FEV1,o was observed in older age group of 60 or more for males. The relationship between prevalence of symp toms and grade of obstruction by function tests was not analyzed because of lack of necessary information.

SUMMARY

In 25 surveys throughout Japan, 1965-1973, the interviews to 22,590 gen eral populations in 21 survey areas were carried out by physicians and public health nurses asking pulmonary symptoms using Japanese version of the BMRC questionnaire for chronic bronchitis with the overall response rate of 90% or Prevalence of Chronic Bronchitis Symptoms in Japan 83

Fig. 2 1 Second Forced Expiratory Volume, by Sex, Age in Survey Areas.

more. This paper reviewed such prevalence rates of the combined pulmonary symptoms, as persistent cough, persistent phlegm, persistent cough and phlegm (PCP), PCP with exacervations and dyspnea and chronic bronchitis syndrome. And the prevalence and smoking effects were analyzed. Sputum examination and pulmonary function tests were also discussed. Among various prevalence rates, prime symptoms, persistent cough and phlegm (BMRC coding (1/3+5+6/8+10) and (5+10) were fairly low in crude mean rates (Fig. 1) as compared to Eng land and the U.S. studies. However, their wide range may imply that the pre valence of pulmonary symptoms in Japan is not static, and relatively short his tory of cigarette smoking and rapid industrialization with air pollution may be possible factors to changing the morbidity of non-specific pulmonary diseases 84 Toshio Toyama and Jun Kagawa

Fig. 3 Percent FEV1 o by Sex, Age in Survey Areas.

to comparable level of the Western countries in some time of future. Over crowding may contribute to increase the prevalence so far as population density is concerned. Although no significance testing has been done, consistent trends were observed demonstrating the increase of prevalence of other pulmonary symptom complex with age and smoking habits. There were also many respects to which further cautions must be needed such as sampling procedure, interview technique, sputum examination and evaluation of pulmonary function. Together with clinical studies, standardized epidemiological survey will be important and useful tool for regional comparison and prevention of the diseases.

Sources of material (Key to the abbreviations is on Table 2. All the reports are written in Japanese) K1: Toyama, T., et al., (1966) Study on the Prevalence of Respiratory symptoms in a Rural Area (Kashima, Ibaragi Pref.) in Japan. J. Air Pollution Research, 1, 24. K2: Adachi, S., et al., (1969) Report on Prevalence of Respiratory Symptoms and Pulmonary Function in Kashima Area. Mimeographed report. K3: Department of Health, Ibaragi Prefecture, (1973) Survey report on Prevalence of Chronic Bronchitis Symptoms in Japan 85

prevalence of pulmonary symptoms in Kashima area*. (Dr. Adachi) A: Department of Environmental Health, Aomori Prefecture, (1973 Report on Prevalence of pulmonary symptoms in Aomori City*. (Dr. Sasaki) AK: Division of Environmental Hygiene, Akita Prefecture, (1973) Report on prevalence of pulmonary symptoms in Akita City*. (Dr. Yoshida) M: Department of Health, Shimane Prefecture, (1973) Report on Preva lence of pulmonary symptoms in Matsue City*. (Dr. Tsunetoshi) S1, S2: Shiojiri City Health Office and Matsumoto Health Center, (1971) Report on community health survey in Shiojiri area (No. 1)*. (Dr. Ishikawa) Fl: Fuji City Health Office, (1972) Report on Prevalence of pulmonary symptoms in Fuji City*. (Dr. Yoshida) F2: Shizuoka Prefecture Department of Health, (1973) Report on prevalence of pulmonary symptoms in Fuji City*. (Dr. Yoshida) C: Chiba City Health Office, (1973) Report on prevalence of pulmonary symptoms in Chiba City*. (Dr. Yoshida) I: Imai, N., et al., (1970) Effects of air pollution on respiratory system in Isoko people (Report 2). Jap. J. of Public Health 16, 891. T: Department of Public Health, Aichi Prefecture, (1972) Report on preva lence of pulmonary symptoms in Tokai City*. (Dr. Shima) KI: Bureau of Environmental Pollution Control, Kitakyushu City, (1973 Report of chronic pulmonary diseases in Kitakyushu City in 1972. (Dr. Uenishi) SA: National Institute of Public Health, (1969) Survey on pulmonary symp tom prevalence among city office workers by BMRC questionnaire in Santama area (Tokyo suburbs) *. Reported partly by Dr. Hitosugi at the 10th Annual Meeting of Association of Air Pollution Research at Tokyo, 1969. N : Nagoya City Health Office, (1973 Report on prevalence of pulmonary symptoms in the south area of Nagoya City*. (Dr. Rokushika) 0: Osaka City Department of Health, (1973) Report on prevalence of pul monarv svmutoms in Osaka City*fl (Dr. Tsunetoshi) TO: Suzuki T., et al., (1966-68) Relationship between air pollution and preva lence of pulmonary symptoms among Tokyo city office employee, un official mimeographed report p. 63. Reported partly by Dr. Hitosugi in J. of Air Pollution Research 3, 32, 1968, and 4, 45, 1969. MI: Mitaka City Office for Health, (1973 Report on prevalence of pulmonary symptoms in Mitaka City*. (Dr. Nishikawa)

* Unofficial reports of the Government. 86 Toshio Toyama and Jun Kagawa

SAK : Sakai City Health Office, (1973) Report on prevalence of pulmonary symptoms in Sakai City*. (Dr. Tsunetoshi) Y : Department of Health, Yokkaichi City, (1973 Report on prevalence of pulmonary symptoms in Yokkaichi City*. (Mie University) YO: Bureau of Environmental Pollution Control, (1971) Report on Pulmo nary Function in Yokohama South Area. A preliminary report* . (Dr. Shishido) KA : Bureau of Health, Kawasaki City, (1971) Report on pulmonary disease survey in Kawasaki City*. (Dr. Terabe) TOY: Osaka Prefecture Department of Health, (1972) Report of pulmonary symptom prevalence in Toyonaka area, Osaka Prefecture*. OM: Bureau of Health, Omuda City, (1973) Report of prevalence of pulmo nary symptoms in Omuda City*. (Dr. Yamaguchi) The authors acknowledge Dr. S. Adachi of Keio University, Dr. S. Tani of the Environment Agency for their cooperation. This paper was presented originally at the World Congress on Asthma, Bronchitis and Conditions Allied held in New Delhi, India 1974. Since the pro ceedings have not been published due to administrative circumstances the paper is submitted to this Journal.

REFERENCES

1. Reid, D. D. and Fletcher, C. M.: International studies in chronic respiratory di sease. Brit. Med. Bull. 27: 59-63, 1971 2. The Asahi Press: The resources of public welfare. Minryoku. Tokyo, 177, 1974 3. MRC: Difinition and classification of chronic bronchitis for clinical and epide miological purposes. Lancet. April 19: 775-779, 1965 4. Medical Research Council's Committee on Research into Chronic Bronchitis (1966) : Instructions for the use of the quetionnaire on respiratory symptoms. 5. Fletcher, C. M.: Chronic bronchitis. Amer. Rev. Resp. Dis. 80: 483-494, 1959 6. Holland, W. W.: The urban factor in chronic bronchitis. Lancet. Feb. 27: 445-448, 1965 7. Fletcher, C. M. et al: The significance of respiratory symptoms and the diagnosis of chronic bronchitis in a working population. Brit. Med. J. Aug. 29, 5147: 257 -266, 1959 8. Higgins, I. T. T.: Respiratory symptoms, Bronchitis and ventilatory capacity in random sample of an agricultural population. Brit. Med. J. Nov. 23: 1198-1203, 1957 9. Higgins, I. T. T. et al: Population studies of chronic respiratory disease. Brit. J. Industr. Med. 16: 255-268, 1959 10. Flecher, C. M.: An account of chronic bronchitis in Great Britain with a com parison between British and American experience of the disease. Dis. of Chest . 44: 1-10, 1963 11. Reid, D. D. et al: An Anglo-American comparison of the prevalence of bronchitis. Brit. Med. J. 2: 1487-1491, 1964 Prevalence of Chronic Bronchitis Symptoms in Japan 87

12. College of General Practitioners: Chronic bronchitis in Great Britain. Brit. Med. J. Oct. 14: 973, 1961 13. Holland, W. W. et at: A comparison of two respiratory symptoms questionnaires.. Brit. J. Prev. Soc. Med. 20: 76, 1966 14. Densen, P. M. et at: A survey of respiratory disease among New York City postal and transit worker. 1. Prevalence of symptoms. Environmental Research. 1: 265 - 286, 1967 15. Ferris, B. G. et at: The prevalence of chronic resporatory disease in a New Hampshire town. Amer. Rev. Resp. Dis. 86: 165-185, 1962 16. Deane, M. et al: Respiratory conditions in outside workers. Arch. Environ. Health. 10: 323-331. 1965 17. Lambert, P. M. et at: Smoking, air pollution and bronchitis in Britain. Lancet. Apr. 25: 853-857, 1970 18. Holland, W. W. et at: Respiratory disorders in U.S. east coast telephone men. J. Epid. 82: 1-5. 1965 19. Holland, W. W. et at: Respiratory disease in England and the U.S. Arch. Env. Health. 10: 338-343, 1965 20. Horton, R. J. M.: Discussion; Epidemiologic studies of chronic respiratory di seases. Arch. Env. Health. 10: 344, 1965