Birth cohort analysis using irregular cross-sectional data: a technical note.

Cancer mortality and morbidity data are usually collected and published by calendar time period and by age class. Transformation of the age-specific incidence or mortality rates into those for birth cohorts is readily undertaken when one age class of each time period corresponds to a given cohort: a requirement that is often not satisfied. The authors propose a method for the computation of birth cohort age-specific incidence rates given irregular cross-sectional data. The procedure is based on a cross-sectional interpolation of cumulated population and case figures, from which cohort rates can be derived. Using the method several examples of trends in cancer incidence by birth cohort are discussed.