Heart Disease Mortality in Cities of Latin America and in Cities and Regions of England and Wales
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Bull. Org. mond. Sant) 1969, 40, 409-423 Bull. Wid Hlthi Org. Heart Disease Mortality in Cities of Latin America and in Cities and Regions of England and Wales PERCY STOCKS, C.M.G., M.D., F.R.C.P., D.P.H.' Death rates from heart disease in cities and regions of England and Wales, based on death certificates for 1963, are compared with death rates from the same causes in 10 Latin American cities, San Francisco, USA, and Bristol, England, derivedfrom the Inter-Ameri- can Investigation ofMortality which obtained histories and clinical records offatal illnesses for the years 1962-64 by a sampling method. Death rates in Bristol derived from the 2 sources showed an agreement close enough to justify comparisons between official ratesfor England and Wales and the data for the Latin American cities. Comparing standardized death rates for males in the Latin American cities with those for the corresponding populations in the English conurbations and cities, the ratio for coro- nary disease was found to be 0.4; for other degenerative heart disease it was 1.0; for hyper- tensive heart, 2.2; for other heart disease, 1.5. The corresponding ratios for females were: 0.55, 1.0, 3.0, and 1.7, respectively. When the hospital regions ofEngland and Wales were included, a geographical pattern could be seen, particularly for males, the highest rates for coronary and degenerative heart disease being found in northern England and the lowest rates in central and western cities of Latin America. For hypertensive and other heart disease the pattern was different. Standardized sex ratios for total heart disease mortality at ages from 45 to 74 years in 30 countries are largely affected by the proportions of deaths attributed to arteriosclerotic and degenerative disease but they suggest that geography, country of origin and paoibly climate are also factors that differentially affect the sexes and, in consequence, affect the sex ratios. Compilations of death rates from different causes justify brief reference to them, before more firmly during the years 1950-61 by Segi, Kurihara & Tsu- based comparisons are considered in relation to the kahara (1966) revealed some remarkable variations recent Inter-American Investigation of Mortality 3 in rates for heart diseases in 30 countries or terri- in Latin American cities, in which the author tories using the International Classification of participated during 1961-66. Diseases (ICD) (1955 revision). In some of these In 1960-61 there were 7 countries whose age- countries the rates are not sufficiently reliable for adjusted rates for total heart disease for all ages per purposes of comparison owing to incomplete certifi- 100000 persons exceeded 300 in males and 175 in cation of cause of death by doctors and irregularities females, and 10 other countries with rates over 200 in coding procedures and application of the rules of and 140 in males and females, respectively. The two selection when more than 1 disease is mentioned South American countries in the series recorded on the certificate. However, enough attention could much lower rates, namely, Venezuela with 164 and be given to age-adjusted rates for most countries 2 to 121, and Colombia with 143 and 125. Rates below those of Colombia occurred only in Japan for males 1 Former Reader in Medical Statistics, University of London and Chief Medical Statistician, General Register 3This research project was made possible by Research Office, London. Present address: 34 Brompton Avenue, Grant GM-08682 from the National Institute of General Colwyn Bay, Wales. Medical Sciences of the United States Public Health Service, 2West Berlin, Greece and Ceylon were disregarded and and by the co-operation and support of Ministries of Health,. the parts of the United Kingdom were combined in the local authorities, and schools of medicine and public health analysis, leaving 25 countries. in the 12 cities concerned. 2311 -409- 410 P. STOCKS TABLE I AGE-ADJUSTED DEATH RATES PER 100000 PERSONS AT ALL AGES FROM HEART DISEASES IN 1960-61 Chronic rheumatic and degenerative Other diseases Hypertensive Total diseases heart disease heart disease of the heart heart disease of the heart Country (410-416) (420 422) (430-434) (440-443) (410-443) M F M F M F M F M F USA 8 8 318 163 14 9 28 30 368 211 United Kingdom 9 13 259 137 20 16 15 14 303 180 Venezuela 6 6 116 78 22 19 21 18 164 121 Colombia 6 8 49 34 73 67 15 17 143 125 and in France, Belgium, Germany and Japan for The apparent differences between Venezuela and females. For arteriosclerotic and degenerative heart Colombia might be due to incomplete identification disease (ICD numbers 420-422) Colombia showed of arteriosclerotic heart in the latter country, but the the lowest rate of 49 for males compared with contrasts between those two countries and the USA 318 in the USA and 258 in the United Kingdom, and the United Kingdom could not be explained in and the rate of 34 for females was below that of all this way. There were similar indications of wide countries except France; in Venezuela the male rate differences from death rates recorded from Chile of 116 was lower than in 20 other countries and and 2 cities of Latin America as shown in Table 2. the female rate of 75 was lower than in 19 countries. The apparent contrasts between Chile and the USA For hypertensive heart (440-443), on the other hand, for arteriosclerotic and total heart, and between the the rate in Colombia exceeded that in 18 countries 2 Latin American cities for heart diseases other than for each sex and the rate in Venezuela for males 420-422, merited investigation, as did the contrasts exceeded that of all countries except the USA. For in Table 1, and these were some of the reasons why other heart disease (430434) also, Colombia the Pan American Health Organization carried out recorded almost the highest rates. Comparisons the investigation of mortality now to be described. with the USA and the United Kingdom are shown in Table 1, but it was impossible to judge from the MATERIALS AND METHODS information available to what extent the large A thorough examination of the clinical histories apparent differences were real. of persons aged 15 to 74 years who died during a TABLE 2 AGE-ADJUSTED DEATH RATES PER 100000 PERSONS AT AGES 15-74 YEARS FROM HEART DISEASES IN 1958-59 Arteriosclerotic Rheumatic fever, Total heart and degenerative Other diseases chronic rheumatic diseases and orcity Years ~~heart disease of the heart heart and hyper Country or city Years (420a422) (430-434) t400416 44s0a-4 hypertensiona(400-447) M F M F M F M F USA 1958 217 81 10 5 35 33 262 119 Chile 1959 63 34 26 21 25 24 114 79 Caracas (Venezuela) 1958-59 177 78 14 11 36 34 227 123 Federal District of Brazil 1958-59 163 78 80 46 90 66 333 190 a Includes acute rheumatic fever and hypertension without mention of heart affection (400-4t2 and 444 447). HEART DISEASE MORTALITY IN CITIES OF LATIN AMERICA AND ENGLAND AND WALES 411 2-year period in 1962-64 in 10 cities of Latin Ame- given by the 2 referees were then combined and rica, and for comparison in San Francisco and divided by 6 to provide the final cause frequencies. Bristol, was made by a team of doctors and reported Since the referees followed the rules of selection upon by Puffer & Griffith (1967). In 8 cities, samples laid down in the International Classification of were taken by drawing every nth death at ages from Diseases (1955 revision), it would be expected that 15 to 74 years from the registers, n being chosen the resulting rates for Bristol would not differ according to the population so as to sample about appreciably from the rates in 1962-64 obtained by 4000 deaths of residents in the city during the 2 years the General Register Office from death certificates, of study. In 4 cities, all deaths at ages from 15 to 74 unless the additional information from the inquiries years were included. The history of each death was and the use of weights in doubtful cases changed the then investigated by examination of hospital and coding of the " underlying " cause to an important autopsy records and by inquiries from doctors and extent. The data for Bristol provided a means of relatives of the deceased person, and age-specific testing the justification for comparing the Latin death rates were evaluated for the cause of death. American rates obtained by sampling with official One requirement for this evaluation was that the rates for cities in England and Wales, and the effects upon the rates of differing concepts of diag- Bristol rates derived by the 2 methods have been nosis, certification methods and coding procedures compared in Table 3. The death rates between the in the various cities should be eliminated, and this ages of 45 and 74 years in both series have been was accomplished as far as possible by submitting standardized by using the populations of males and all the collated information concerning deaths females in England and Wales in the middle of 1963 involving cardiovascular disease to the same 2 as standards. The period during which the sample referees who decided independently what they was drawn was October 1962 to September 1964, believed to have been the " underlying " cause of and the official data of registered deaths have been death. To help such decisions in difficult cases assessed by aggregating the appropriate fractions for involving more than 1 disease, the referee assigned, 1962, 1963 and 1964 and dividing by twice the mid- when in doubt, a weight of 2 to the most likely and 1963 populations.