[Comparison between several standard populations for age-adjusting].
BACKGROUND
To analyse the effect the choice of reference population has on different indicators derived from mortality rates age-adjusting.


METHODS
The mortality rates for different causes of death in Spain from 1971 to 1992 were adjusted by using four reference populations: Spanish populations from 1971 and 1992, the Standard European population and the standard world population. The results obtained with the four populations were compared by applying three indicators: difference between the rates of 1992 and 1971, ratio between the rates of 1992 and 1971 and annual percentage change between 1971 and 1992.


RESULTS
In the majority of the causes of death studied, including the total, ischemic heart disease and almost all of the tumours, the ratio between the rates and the percentage of annual change are similar regardless of the standard population used. However, the difference in rates is very noticeable in relation to the reference population. In the infectious diseases and testis cancer, the opposite occurs: the different in rates is steadfast while the ratio between the rates varies with the standard population. Finally, the mortality due to pneumonia, Parkinson's disease and encephalic cancer show changes all three indicators used.


CONCLUSIONS
An analysis of the specific rates by age must be made before proceeding with their adjustment. This analysis will enable us to ascertain whether the adjustment by age is correct and which indicator (difference, ratio or percentage change) will be appropriate for making comparisons.
Llorca Díaz
J
J
Cátedra de Medicina Preventiva y Salud Pública, Facultad de Medicina, Universidad de Cantabria, Santander. llorcaj@medi.unican.es
Prieto Salceda
D
D
Dierssen Sotos
T
T
Delgado-Rodríguez
M
M
D017677:Age Distribution; D002423:Cause of Death; D006801:Humans; D012015:Reference Standards; D013030:Spain / Q000453:epidemiology