Time trends of esophageal and gastric cancer mortality in China, 1991-2009: an age-period-cohort analysis

Abstract

Esophageal and gastric cancers share some risk factors. This study aimed to compare the long-term trends in mortality rates of esophageal and gastric cancers in China to provide evidence for cancer prevention and control. Mortality data were derived from 103 continuous points of the Disease Surveillance Points system during 1991-2009, stratified by gender and urban-rural locations. Age-period-cohort models were used to disentangle the time trends of esophageal and gastric cancer mortality. The downward slope of the period effect for esophageal cancer was steeper than that for gastric cancer in rural areas. Cohort effect patterns were similar between esophageal and gastric cancers, with an inverse U-shape peaking around the late 1920s and early 1930s. A second peak, appearing around the 1950s, was weaker than the first but apparent in males, especially for esophageal cancer. The more marked changes in period effect for esophageal cancer in rural areas suggest esophageal cancer screening practices are effective in reducing mortality, and similar programs targeting gastric cancer should be implemented. The similarities of the cohort effects in these two cancers support the implication of nutrition deficiency in early childhood in the development of upper gastrointestinal cancer.

Figure 1

Age-specific mortality rates of esophageal and gastric cancers by period of death, stratified by region and sex during the period of 1991–2009. (a–d) In the first row represent esophageal cancer mortality; (e–h) In the second row represent gastric cancer mortality.

Figure 2

Cohort-specific mortality rates of esophageal and gastric cancers on a log scale in different age groups, stratified by region and sex during the period of 1991–2009. (a–d) In the first row represent esophageal cancer mortality; (e–h) in the second row represent gastric cancer mortality.

Figure 3

Age, period, and cohort effects on esophageal cancer and gastric cancer mortality, stratified by region and sex. (a–d) In the first row represent age-specific mortality rates in the reference period of 2000 after adjusting for period and cohort effects. (e–h) In the second row are the estimated period effects, and the blue dot is the reference period. (i–l) In the last row are the cohort effects, and the blue dot is the reference cohort.

Figure 4

Locations of the 103 continuous disease surveillance points by urban and rural status in China. This map was generated by ArcGIS software, version 10.2 (http://www.esri.com).