Impact of injury mortality changes on life expectancy in Tianjin, 2003 and 2021

Objective: To analyze the impact of injury mortality changes on life expectancy (LE) in Tianjin in 2021 compared with 2003 by age, gender, urban-rural, and cause-specific differences. Methods: The abridged life table and Arriaga's decomposition method were applied to analyze the cause of death surveillance data of Tianjin residents in 2003 and 2021, calculating the age-specific and subcategory-specific contribution of injury to the increase of LE. Results: From 2003 to 2021, the injury mortality rate dropped from 30.33 to 21.57 per 100,000 in Tianjin. Over this period, LE varied from 77.70 to 82.03 years, with an increase of 4.33 years. The reduction in injury mortality contributed 0.3111 years (7.18 %) to the growth of LE. The positive impact on LE was notably observed in the age group of 1-49 years, contributing 0.4348 years (10.04 %) cumulatively. The major injuries that contributed significantly to the increase of LE were transport accidents excluding motor vehicles (0.2558 years, 5.91 %), accidental poisoning (0.0845 years, 1.95 %), motor vehicle traffic accidents (0.0474 years, 1.09 %), and drowning (0.0359 years, 0.83 %). However, the rise in intentional self-harm mortality rate from ages 10-24 and increased mortality rates due to other accidents and adverse effects, motor vehicle traffic accidents, and falls from ages 50+ had negative impacts on LE. Conclusion: During 2003-2021, the decline in injury mortality rates among children and young to middle-aged individuals in Tianjin played a crucial role in the increase of LE. It is essential to enhance primary prevention efforts, particularly focusing on key populations, to reduce the negative impact on LE growth from intentional self-harm, other accidents and adverse effects, motor vehicle traffic accidents, and falls.