Age-period-cohort analysis of breast cancer mortality rates in Andalucia (Spain)

Background: The aim of this paper is to analyse breast cancer mortality in Andalucia (Spain) between 1975 and 1999 based on age-period-cohort. Patients and methods: Mortality data were obtained from the Mortality Registry of Andalucia. Deaths and population were divided into 13 age groups and five 5-year periods. From this, age-specific mortality rates for 17 birth cohorts were computed. These were plotted and fitted to Poisson regression models to assess age, period and cohort effects. Results: The best fit was found for the complete model, which simultaneously considered the effects of age-period-cohort. Cohort effects were found to be more important than period effects in terms of model fit. Conclusion: These effects were manifest as a seemingly consistent increase in the relative risk of breast cancer mortality with a three-fold increase in women born in the 1950s relative to those born in the 1890s.