Cancer Incidence and Prevalence in the Oldest Old: Disentangling Age, Period, and Cohort Effects

Heidi Hanson, Huntsman Cancer Institute
Ken R. Smith, University of Utah
Antoinette Stroup, Utah Cancer Registry
Janna Harrell, Utah Cancer Registry
Ruldoph Rull, Northern California Cancer Center

The projected rapid growth of the 85+ population makes it an important age group to study morbidity trends. Cancer incidence in this age group is understudied because data are not easily accessible. This study uses data from the Utah Cancer Registry (UCR), US Census, and National Center for Health Statistics (NCHS) to generate age-specific estimates of cancer incidence for the oldest old (85+) from 1973 to 2002 for Utah. Age-period-cohort (APC) analyses are used to describe the simultaneous effects of age, period and cohort on cancer incidence rates. Our results show that cancer incidence rates increase up to the 85 – 89 age group and are followed by slight declines for ages 90 -99 net of period and cohort effects. We also find evidence of period and cohort effects, suggesting that biological mechanisms are not the only factors contributing to the declining of cancer incidence between the ages of 85 and 100.