Community screening programs of cancer and cardiovascular diseases in Japan.

The Health and Medical Services Law for the Aged was implemented from February, 1983 in Japan. This paper describes the present status of health examination programs and cancer screening programs and related issues as follows : methods of the basic health examination and cancer screening, the number of the examinees, detection numbers and rates of targeted diseases, i.e. hypertension, anemia, cancer of the stomach, uterus, lung, breast, and colon etc. The Goals of Japanese Government of the Health Services by the year 2000 are discussed from the several points of view.

According to the Japan vital statistics, until the middle of the 20th century, death due to infectious diseases such as pneumonia, bronchitis, tuberculosis and gastroenteritis prevailed in Japan. As shown in the Figure 1, after the Second World War (1945), they have rapidly decreased and have been supplemented by cerebrovascular diseases, malignant neoplasms and heart diseases1).
In 1951, the death rate from stroke became to be the leading cause of death among all deaths. In the same time, the mortality rate from cancer and heart disease were the second and third leading cause among all deaths, respectively.
These three chronic diseases account for approximately twothird of causes of all deaths of the Japanese (Figure 2)2). Therefore, the main objective of public health policy in Japan was prevention and also reduction of the mortality rates of the three major chronic diseases, i.e. cancer, heart disease, cerebrovascular disease.
In 1960, the deaths due to stomach cancer accounted for more than one-half of all cancer deaths (51.6%) in males. In females, the deaths due to stomach and uterine cancer amounted to 54.6 % of all cancer deaths. Accordingly, the main target organs of cancer control activities in Japan were the stomach and the uterus.
At that time, we had not the effective methods for primary prevention, i.e. reduction of incidence of stomach and cervical cancer, but clinical physicians experienced that the earlier the detection, the better the prognosis of patient with stomach can-cer or cervical cancer. Therefore, we felt it mandatory to extend our efforts into the general population to perform cancer screening for early detection.
Since around 1960 mass screening programs for stomach and cervical cancer were started actively and systematically in several municipalities, and gradually spreaded nationwide in Japan. The purposes of cancer mass screening should be the early detection and prompt treatment to reduce the cancer mortality in a given population. This is the secondary prevention.
On the other hand, it was known that excessive intake of sodium chloride resulted in cardiac infarction and stroke which were known to be fetal. For prevention of these diseases, it was essential to properly limit the salt intake 3).
Since around 1950 the campaign of "low salt intake in daily diet"-activity for prevention of hypertension which was closely related to cerebrovascular diseases began as national health policy, and also mass screening programs for the same objective has been conducted nationwide by measurement of blood pressure, examination of urine, examination by electrocardiogram, funduscopic examination and others1).
to provide comprehensive health and medical services such as disease prevention, treatment and functional training in order to ensure the maintenance of good health and appropriate medical care for elderly Japanese people, thereby improving the national health and promoting the welfare of senior citizens4).
The types of the health services other than medical care based on the Law are as follows : (1) The issuance of a Health Handbook (2) Health education (3) Health counseling (4) Health examinations (5) Functional training (6) In-home visit guidance These health services were started in a comprehensive way intended for regional residents aged 40 or more with the aim of maintaining health in elderly people.
This paper is mainly concerned with the current status and evaluation of health examinations above mentioned.

THE HEALTH EXAMINATION PROGRAMS
The main bodies operating the health examination services to   (b) it must lead to early detection of the disease and better prognosis of the patients ; and (c) evidence that death rate from cancer is reduced in a population screened, should be obtained from well conducted studies, preferably from a randomized controlled trial which is said the best method, or second best methods, i.e.case-control study, time-series study, follow-up study, etc. Table 2. shows the present methods of cancer screening programs in Japan6).

Goals of the Health Services4)I
Japanese government decided the goals of the "Third Eight-Year Health Service Program". Reduction of mortality rates of three major chronic diseases (cancer, heart disease and cere-

Results of Mass Health Examination and Cancer Mass Screening7)
According to the report from the Statistics and Information Department, Minister's Secretariat, Ministry of Health and Welfare, Japan, the number of examinees has been increasing annually. These numbers of examinees and diseases detected, and rates of examination and detection for 1993 are shown in Table 37).
Theses numbers given above do not include the examinees of health check-ups conducted under the laws other than the Law for the Health and Medical Services for the Aged (i.e.The Industrial Safety and Health Law).

EFFECTIVENESS OF THE HEALTH SERVICES
Evaluation of Cancer Mass Screening Programs There are many methods and steps to investigate the accuracy of screening test, the feasibility of mass scale program, and the effectiveness of mass screening program (Table 4). In these methods, there have been many studies carried out in Japan. Table 5 shows research efforts design to evaluate the effectiveness .  The objective of mass health examination is to achieve a reduction of mortality rates of major chronic diseases (cancer, heart disease, cerebrovascular disease, diabetes etc.) by improvement of health education and health counseling and effective promotion of guidance for improving daily living habits.

Evaluation of mass health examinations
There have been also many studies to investigate the effectiveness of mass health examination by comparing between the incidence of stroke or heart disease and hypertension, serum cholesterol level, etc.
In Japan, the mortality from stroke decreased dramatically during recent decades, however, the report from the Ministry of Health and Welfare of Japan showed us that the incidence of stroke never decreased, indicating that non-fetal stroke rather increased. According to the report of Abe, K. and Imai, Y.8), the meta-analysis of primary prevention trials demonstrated that a modest decrease in diastolic blood pressure, that is 5 mmHg or so, associated with a significant reduction in stroke mortality by 28%,whereas mortality of coronary heart disease reduced by only 8%, which was not statistically significant. CONCLUSION The widespread programs of health services (mass health examination and cancer mass screening) based on the Law of the Health and Medical Services for the Aged is considered to be effective in reducing the morbidity and mortality rates from the major chronic diseases mentioned above in a target age population.
We have the Goals of reduction of these mortalities, however, according to government officials,4) Ministry of Health and Welfare, it seems possible to reduce the mortality rates of stomach cancer, uterine cancer and cerebrovascular disease to the level of Goals we set up. And it seems rather difficult to achieve the Goals for lung cancer, colon cancer, breast cancer and heart disease.
Therefore, it is necessary to investigate the effective methods ; for instance, improvement of comprehensive primary prevention for not only cancer but also heart disease and cerebrovascular disease, promotion to receive health check-up and/or can-cer screening.
Finally, I would say that we have to make our efforts to accelerate and achieve the Goals in Japan by the year 2000.