Mortality Atlas of Cancer and Other Causes
Spain 1975-1986

ATLAS 1978-1992

INTRODUCTION

The last few years have witnessed a considerable effort world-wide to produce geographical studies of cancer and so furnish a collection of maps depicting the distribution of mortality (or incidence) for different tumor sites. To date, cancer atlases have been published in a number of countries, such as Canada, China, England and Wales, France, the former Federal and Democratic Republics of Germany, Japan, Holland, Australia, New Zealand, Norway, Denmark, Finland, Switzerland, Austria, Italy, Portugal, Taiwan, the United States of America, Scotland, Belgium, Poland, Brazil, Uruguay, Spain, the countries of Scandinavia and the European Union (1).

Mortality is the data source most frequently used for geographical studies, coming as it does from a document -the death certificate- which is always issued and for which there is a common denominator: a formal set of coding protocols (International Classification of Diseases), applicable to all signatory countries. Furthermore, mortality-based information has proved to be adequately valid for the purposes of studies into cancer (2,3).

Cancer atlases provide graphic representation of the geographical distribution of diseases, and their underlying goal ranges from simple illustration to the generation of etiological hypotheses. Simultaneous examination of maps plotting different pathologies or comparison of these against theme-specific maps depicting other socio-health indicators, helps suggest possible explanations.

The message conveyed by these maps is straightforward: "cancer is more frequent in some areas than in others and, in theoretical terms, it is possible for mortality to be reduced to those levels prevailing in lower-risk areas" which may in turn act as a springboard for research hypotheses.

The precedent for the present project is the " Atlas of Cancer in Spain" Atlas del Cáncer de España.1975-77 (4,5)


Published in the latter part of 1984. It covered provincial distribution of Standard Mortality Ratios (Indices de Mortalidad Estandarizada, SMR), in respect of both sexes, for all malignant tumours under List A of the International Classification of Diseases (ICD) (4, 5) over the calendar period 1975-1976-1977. Spatial distribution patterns of cancer in Spain exhibited a wide variation as between the different tumor sites. Particularly remarkable was the presence of greater mortality induced by certain given tumours in the provinces of Cadiz, Malaga, Huelva and Seville. In some tumours, a distribution profile was observed which could conceivably coincide with that of industrialization in Spain.

The new Atlas seeks to update the previous edition and cover a wider period of time. This would contribute to greater stability in mortality indicators, with dynamic analysis making short-term forecasts feasible. Similarly, endeavours have been made to study all tumour sites and other causes of death, and thus overcome the limitations imposed by the brevity of the ICD lists. A further limitation placed on the previous version was the use of an indicator (SMR) which hindered interprovincial comparison. This has been solved by recourse todirect method adjustment and relative effect estimators (relative risk) which, apart from being comparable, retain the SMR qualities of intuitive interpretation.

Although this is essentially an Atlas of Cancer Mortality, it includes 18 rubrics which do not correspond to this pathology. There are two reasons for this: 1) to take into account the possible influence and distribution of competitive causes of death (6) (e.g., lung cancer versus myocardial infarction); and 2) to ascertain mortality distribution for other causes and large groups of pathologies.

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Contents | Material and Methods | Results| Coments | References | Maps Guide