The first classification of deaths according to cause of death goes back to the decade 1861-1870. This first classification only had five diseases. Subsequently, the cause of death was classified according to the list of 99 diagnoses by Dr. Bertillón which made up the origin of the International Classification of Diseases (ICD) from the World Health Organisation (WHO) which is currently used to code the causes of death. Today this classification consists of more than 12.000 diseases.
Nevertheless, to be able to speak of the modern statistic on the cause of death, we have to jump forward in time to 1951 as it was then when apart from using the ICD, international regulations were established for the selection of the basic cause of death.
Currently the statistic which reflects natural population movement is the deaths statistic according to cause of death. This statistic is carried out according to criteria established by the WHO in the ICD.
In this classification it is recommended that the cause of death that must be investigated and tabulated is the basic cause of death. This is defined as the disease or lesion which started the chain of pathological events. When the cause is trauma, the events surrounding the accident or act of violence leading to the fatal injury are regarded as the basic cause.
Specifically, this set or chain of diseases is what the death certifying doctor should supply in the statistical bulletin. Based on these causes, denominated by the WHO immediate, intermediate, fundamental and other processes, and following international guidelines for the selection of the basic cause the latter will be arrived at.
Data on causes of death is collected in three statistical questionnaire models: Medical Death Certificate/Statistical Death Register (CMD/BED), Judicial Statistical Death Register (BEDJ) and Statistical Bulletin of Infants who died within 24 hours (BEP). The first one collects data on deaths due to natural causes, without requiring the intervention of a judge, whereas the second is directed at obtaining information on deaths due to causes requiring judicial intervention, since there are signs of a possible accidental or violent cause; both contain data on deaths among those who have lived more than 24 hours. Deaths occurring within 24 hours of life are collected in the BEP.
The sections in the bulletins containing the causes of death are different in the following models. In the CMD/BED, 4 causes are described, which form the chain of illnesses which led to death, in the BEP only two are shown, one relating to the mother and another to the foetus, and in the BEDJ the external circumstances that caused the death are shown.
This statistic supplies information on the mortality dealing with the basic cause of death, its distribution by sex, age, residence and month of death. It also offers indicators which facilitate carrying out geographical comparisons and measuring premature mortality: standardised rates of mortality and potential years of lost life, on an Autonomous Community level and large groups of causes of death.