Different trends in colorectal cancer mortality between age groups in China: an age-period-cohort and joinpoint analysis

Abstract

Objectives: China is undergoing a rapid aging transition. The trends in age-specific mortality rates from colorectal cancer remain unknown, and a number of studies have not distinguished the age, period, and cohort effects simultaneously.

Study design: A descriptive study was implemented with a joinpoint regression analysis and age-period-cohort (APC) model based on the intrinsic estimator (IE).

Methods: Age-specific mortality rates of colorectal cancer (1987-2016) were collected by gender (men/women) and region (urban/rural). The average annual percentage change (AAPC) and relative risks in the trend were identified using joinpoint Poisson regression and APC model (IE), respectively.

Results: Joinpoint regression analysis revealed that the rates decreased in the younger (men aged <45 years and women aged <75 years) but increased in the older (men aged >75 years and women aged >80 years) age groups. The APC model (IE) showed that the rates increased with age and time period but decreased with birth cohorts. But from 2000 to 2005, the period effects showed a substantial decline among urban residents. From the 1910-1914 to the 1915-1919 birth cohort, mortality increased among men, and from the 1925-1929 to the 1930-1934 birth cohort, mortality increased among rural residents.

Conclusions: The trends in colorectal cancer mortality are different between age groups. The younger age groups show a decreasing trend, whereas the older age groups an increasing trend. Cost-effective prevention and control should be implemented more in the elderly and for older cohorts at high risk.

Keywords: Age–period–cohort model; Cancer mortality; Joinpoint regression analysis; Trends.