Chinanews, Beijing, Mar. 6 – According to a report of the People's Daily, a new medical conclusion has been put forward from the research on the epidemic tendency and prevention of malignant tumor, that population aging is a main factor leading to the increase of malignant tumor incidence. This project is led by Hao Xishan, M.D., President, Tianjin Medical University and Academician of Chinese Academy of Engineering. Recently, this project has won the 2nd Prize of the National Sci-Tech Progress Award.　　According to the analysis on the mortality rate of malignant tumor in the 4,000,000 city population (1981—2000), professors of this project find the accumulative incidence of malignant tumor has increased by 45.35% within recent 20 years, during which period the population enjoys an average of 7 years longer life than people 20 years before, and the old people above 65 years old now take up 12.62% of the total population, as against the previous 5.75%.Research shows that the variation of people’s age composition is a decisive factor among all elements resulting in malignant tumor. To be more specific, malignant tumor incidence rate has increased by 11.44 out of 100,000 persons when people become one year older.