Trend of liver cancer mortality in China during 2004-2012 by using trajectory model

Objective To understand the trajectory of age specific liver cancer mortality with year in different areas and in urban and rural areas in China from 2004 to 2012. Methods The data of age-specific liver cancer mortality in different areas (eastern, central and western) and in rural/urban were collected fromNational Death Cause Datasets of Disease Surveillance Systembetween 2004 and 2012. The trajectory model was used to analyze the change trend of liver cancer mortality by using software SAS 9.2. Results The trajectories of age specific liver cancer mortality in different areas and in urban/rural areas could be indicated as 3 kinds of curves according to the criteria of the evaluation, the first and second curves shown a downward linear trend, and the third one was a 'down-up-down' cubic curve. In urban area, the trajectories of liver cancer mortality showed a same liner decline trend in age groups 30-54, 55-74, and 75 years. In rural area, the trajectories for the age groups 30-49 years in the eastern, central and western areas were same. The trajectories for the age group 50-64 years in the eastern, central and western areas, age group 65-69 years in eastern area and for the age group 65-74 years in the western area were same, showing the second downward trend. The trajectories for the age group 75 years in the eastern, central and western areas, for the age group 70-74 years in the eastern and central areas and for the age group 65-69 years in the central areas were same, showing a down-up-down cubic curve. In the age group 50-54 years, the trajectories were different between urban area and rural area. In rural area it belonged to the second kind curve and in urban area it belonged to the first kind curve. The mortality in the rural area was higher that in the urban area. This phenomenon was observed in rural residents aged 65-69 years in the central area and rural residents aged 70-74 years in the eastern and central areas, the death age of liver cancer in the rural area was earlier than one in urban a reaa into the next higher trajectory subgroup. Conclusion Identifying the different trajectories of age-specific liver cancer mortality in different areas and in rural and urban area is helpful for taking targeted measures for liver cancer prevention and control to reduce the risk of liver cancer death.