Recent Decrease in Colorectal Cancer Mortality Rate is Affected by Birth Cohort in Korea

Background: Colorectal cancer mortality has started to decrease in several developed countries in Asia. Thecurrent study aimed to present the long-term trends in colorectal cancer mortality in Korea using joinpointanalysis and age-period-cohort modeling. Materials and
Methods: The number of colorectal cancer deaths and thepopulation for each 5-year age group were obtained from Statistics Korea for the period 1984-2013 for adults 30years and older. Joinpoint regression analysis was conducted to determine changes in trends in age-standardizedmortality rates, and age-period-cohort analysis was performed to describe trends in colorectal cancer mortalityusing the intrinsic estimator method.
Results: In men, the age-standardized mortality rate for colorectal cancerincreased from 1984 to 2003, and the mortality rates stabilized thereafter, whereas the mortality rate of colorectalcancer in women has decreased since 2004. The age-specific mortality rate of colorectal cancer increased inboth men and women over time, whereas decreases in the age-specific mortality rate in younger cohorts wereobserved. In the age-period-cohort analysis, old age and recent period were associated with higher mortality forboth men and women. The birth cohort born after 1919 showed reduced colorectal cancer mortality in both menand women.
Conclusions: Our study showed a recent decreasing trend in colorectal cancer mortality in womenand a stable trend in men after 2003-2004. These changes in colorectal cancer mortality may be attributed tobirth cohort effects.