Time-trend analysis of mortality from malignant tumors of the nervous system in Spain, 1952-1986.

We analyzed time trends in mortality from malignant tumors of the nervous system (MTNS) in the adult Spanish population during the period 1952-1986, using Poisson regression analysis of age at death, year of birth and year of death. During such period, mortality rose especially in the elderly as well as among young and middle-aged men. We found two modest period effects, in both sexes attributed to changes in certification practice. An ascending effect in cohorts born up to 1920 in males and females was attributed to improvements in ascertainment. A positive, progressive, cohort effect in males born post-1920 was detected. Mortality from MTNS in Spain was medium-high with a tendency to rise, most likely due to improvements in diagnosis and registration. From this analysis, the existence of a true increase in incidence of brain glioma among young and middle-aged male adults during recent decades is suggested.