PAN AMERICAN HEALTH SECOND MEETING ORGANIZATION 17-21 June 1963 Washington, D.C. ADVISORY COMMITTEE ON MEDICAL RESEARCH INTER-AMERICAN INVESTIGATION OF MORTALITY Ref: RES 2/8 2 May 1963 PAN AMERICAN HEALTH ORGANIZATION Pan American Sanitary Bureau, Regional Office of the WORLD HEALTH ORGANIZATION WASHINGTON, D.C. RES 2/P REGIONAL DEVELOPMJiLNT CF LPIDJ4ICILOGICAL STUDIES INTER-AIMERICAN INVESTIGATICN UF IVOCTALITY * The Inter-American Investigation of Mortality, a co- operative research program made possible by a grant from the National Institutes of Health, United States Public Health Service, was initiated early in 1962. The research plan, outlined in a report (RES 1/8) to the First Meeting of the PAHG Advisory Committee on Medical Research, provides for the submission of clinical and other information in a standard form from collaborating centers in 12 cities with the object of establishing reliable and comparable estimates of mortality for different causes of death for the populations cDncerned. The present report gives information about the progress of the investigation and an indication of some of the preliminary results obtained. Progress of the Investigation Of the 12 research centers which are now cooperating in the project, four are established in schools of publie health, two in schools of medicine and two in existing research institutes. The remaining four centers are located in the *Prepared for the Second Meeting of the PAHO Advisory Committee on Medical Research, 17-21 June 1963, by the Medical Officer, Health Statistics Branch, PASB. - 2 - RES-- 2/8 central offices of national or local health administrations and in three of them the principal collaborator is also actively associated with a school of medicine or public health. In each center a principal collaborator is in charge of a small staff, consisting of medical interviewers, social workers and a secretary, whose task it is to complete approximately 2,000 questionnaires each year, for two vears, concerning deceased residents of the city aged from 15 to 74 years. The following table sets out for each city the period to be covered by the field of investigations and the number of completed questionnaires received in Washington up to the end of April 1963. Inter-American Investigation of DMIortality, Study Period to be Covered in 12 Cities and Numbers of Completed Questionnaires April 30, 1963 City Study Period Completed Questionnaires Bogota, Colombia Jan. 1962-Dec. 1963 1,413 Bristol, England Oct. 1962-Sept. 1964 496 Cali¡ Colombia May. 1962-April 1964 1,609 Caracas, Venezuela Jan. 1962-Dec. 1963 1,644 Guatemala City, Guatemala Mar. 1962-Feb. 1964 1,100 La Plata, Argentina Jan. 1962-Dec. 1963 1,543 Lima, Peru Jan. 1962-Dec. 1963 1,454 Mexico City, Mexico Mar. 1962-Feb. 1964 1,070 Ribeirao Pr^to, Brazil Jan. 1962-Dec. 1963 575 Sao Paulo, Brazil Jan. 1962-Dec. 1963 1,756 San Francisco, California Oct. 1962-Sept. 1964 51 Santiago, Chile Jul. 1962-June 1964 907 - 3 - RES 2/f Some changes had to be made in the original plan. Delays were encountered in establishing centers in English-speaking cities and the field work in Bristol, England, did not start until October 1962 and in San Francisco, California, until January 1963. Ribeiráo Preto was initially regarded as part of the project in Sao Paulo but is now operating as a separate center. The names and positions of the principal collaborators are set out in the Appendix A. The progress of the field work has varied from city to city depending on the nature of the local problems that had to be overcome and on the availability of suitable staff. The processing of the data, centrally, has been delayed because Dr. Percy Stocks, one of the two medical referees, who had planned to work as medical referee for three periods during 1962, was able to work only for one period but will devote June and July, September and October, 1963 to this project. Dr. Dario Curiel, the other medical referee, has meanwhile been able to review a large part of the material. The t ocessing of the data for machine tabulation can, of course, be completed only after the referees have reviewed that part of the material which is to be referred to them in accordance with the study design. In four of the cities (Cali, Guatemala City, La Plata and Ribeirao Preto) all the deaths of residents aged 15-74 years are investigated. In the other cities the total of deaths in this age range would be too large to be manegeable and a systematic sample is therefore drawn for study using an appropriate sampling - 4 - RE1S 2/1 factor. In these cities tests have been made periodically to see that the sample selected for investigation was properly representative. The results have indicated that the selection procedures being followed yielded satisfactory samples in all cities except one. In this latter city the procedures had to be changed in order that the deaths included in the investigation were truly representative of the mortality experience of the population concerned. Some Preliminary Results In June-July 1962 a limited analysis was undertaken of 1,561 questionnaires from 7 cities with the object of evaluating the progress of the project and assessing the suitability of the data being obtained from the point of view of the objectives of the investigation. Comparison of the cause of death as stated on the death certificate with the final assignment made by the medical referees after reviewing the additional information in the ouestionnaire indicated that in every city we can expect the resulting pattern of mortality to differ in certain significant respects from that which appears in the customary statistics. For example, the number of deaths assigned to ill-defined causes will be reduced, the nurmber of maternal deaths increased, and the body site involved in deaths from cancer will be designated with more precision in many irstances. Though based on relatively small numbers from any one city, this preliminary analysis suggested also that significant differences between cities in the relative frequency of different cancers and of the tyw s of -5- PES 2/8 cardiovascular diseases would emerge. In January 1963 an analysis was made of 1,239 deaths from cancer in five cities and the results were reported to a Conference on Epidemiological Research on Cancer held in Lima, Peru, in February 1963.* Two tables are appended to this present report which indicate the nature and quality of the data on cancer. These tables are similar to tables presented to the Lima conference but have been brought up-to-date and now deal with 1,525 cancer deaths. The first table (Appendix B) shows for each of the five cities, the number of deaths attributed to the main sites of cancer and the number that would have been expected if, in each of five age-groups, the deaths from cancer in the city had been distributed by body site in the same way as cancer deaths in the same age group in the white population of U.S.A. in 1959. From this table it is clear that, when compared with the United States, gastric cancer accounts for an unusually high proportion of cancer deaths in all five cities. Cervical cancer is unusually common in Cali and in Lima and, to a lesser extent, in Caracas. Iung cancer is unusually frequent in La Plata and reb tively infrequent in Cali and Lima. Oesophageal cancer is more common in La Plata and Sao Paulo but not markedly so in the other cities. Cancer of the intestine is relatively uncommon in Cali and Caracas, and to a lesser extent in Sao Paulo. Another finding, not shown in this table, is that cancer of the urinary bledder in La Plata is apparently unusually frequent among males, there being 21 deaths while F'expected"' deaths were 8.4. This form of cancer does not *See RES 2/ 7 - 6 - R.ES 2/8 occur more frequently than expected in the other four cities, nor is it urnduly frequent among females in La Plata. It is encouraging to note from the table in Appendix C that the diagnosis as regards body site was well established in a high proportion of cancer deaths. In these cities it will be seen that in 90 per cent of deaths from malignant diseases there was additional evidence in the form of histological reports, gross findings at surgical operation or autopsy, radiological or cytological findings to support the clinical diagnosis. The proportion of deaths where such supporting evidence was obtained was even higher than this in cancer of the biliary tract (93 per cent), the bladder (95 per cent), cervix uteri (96 per cent), the lung (99 per cent), and in leukemia (94 per cent). A study of the first yearts material from Ribeirao Preto has indicated very clearly the importance of "cardiopathy" as a cause of death in that city, particularly at younger ages. If deaths from violent causes are excluded, nearly one death in three in the age range 15 to 44 years would seem to be due to this condition. The clinicai features presented by these fatal cases resembly closely the classical picture of chronic Chagas' disease. There is, however, need for more general agreement.:on the criteria, both clinical and pathological, vrhich should determine whether a death is properly to be attributed to this condition. All aquestionnaires from Ribeirao Preto -- as well as a few from Sao Paulo and Caracas -- where Chagas' disease was thought to have been concerned as the sole, the main or a contributory cause -7- RES 2/8 of death have been identified and it is hoped to arrange for these questionnaires to be reviewed by a panel of specialists with a view to defining what the criteria should be for assigning a death to Chagas? cardiopathy.