[Study on increase of average life expectancy of residents in Tianjin from 1999 to 2018]

Objective: To assess the trend and the factors responsible for the increase of life expectancy of residents in Tianjin over the past two decades. Methods: Abridged Life Table and Arriaga's decomposition method was applied to quantify the influence of the age structure and the leading causes of death on the increase of life expectancy of residents in Tianjin from 1999 to 2018. Results: In the past 20 years, the life expectancy of residents in Tianjin increased by 4.97 years, the life expectancy of men and women increased by 4.11 years and 5.86 years, respectively. The decrease of mortality rate in 0-year-old group contributed 19.17% to the increase of the life expectancy, while the decrease of mortality rate in residents aged ≥55 years contributed more to the increase of life expectancy, with the cumulative contribution rate of 67.38%. The major contribution to the increase of life expectancy was the mortality reduction of cerebrovascular disease, respiratory disease, cardiovascular disease, perinatal diseases, congenital malformations and injury, with the contribution percentage of 27.27%, 21.37%, 15.76%, 12.22%, 6.44% and 4.86%, respectively. The increase of mortality of malignant tumor, injury and poisoning, diabetes and nervous system diseases and others had a negative effect on the increase of life expectancy of people aged ≥75 years. From 1999 to 2018, the life expectancy increased from 76.72 years to 81.46 years (t=9.11, P<0.001), the annual percent change (APC) was 0.58%. From 2011 to 2018, it was stable, ranging from 81.46 years to 81.69 years (t=0.89, P=0.387, APC=0.13%). Conclusion: From 1999 to 2018, the increase of life expectancy was attributed to the decrease of mortalities in infants and the elderly and the decrease of mortalities of cerebro-cardiovascular disease, respiratory disease, perinatal disease, congenital malformations and injury. However, these positive contributions were partly offset by the negative contribution of malignant tumor, injury, diabetes and nervous system disease in those aged ≥75 years. Comprehensive prevention and control of key diseases should be strengthened in key population in order to further improve the life expectancy of the population.