How does chronic disease influence subjective life expectancy among middle‐aged and older adults? Evidence from the China Health and Retirement Longitudinal Study (CHARLS) 2018 cross‐sectional data

Chronic diseases have become one of the most important factors threatening human health. Subjective life expectancy (SLE) describes an individual's expectation or subjective perception of lifespan. This article aims to explore the relationship between chronic diseases and SLE, as well as the differences among different age groups and different types of chronic diseases in this relationship. China Health and Retirement Longitudinal Study (CHARLS) is a nationwide longitudinal study that evaluates the social, economic, and health conditions of middle-aged and older adult families and individuals aged 45 and above in China. In this study, CHARLS used probability proportional to size sampling (PPS sampling) to ensure the breadth and representativeness of the sample. This study selected cross-sectional data from CHARLS 2018, removed missing values, and obtained a valid sample of 10,658 middle-aged and older individuals, of whom 8564 had chronic diseases. After controlling demographic, health behavior, socioeconomic, psychological, and social security factors, an ordered logistic regression was performed to explore the relationship between chronic disease and SLE in middle-aged and older adults. The results show that chronic diseases negatively correlate with SLE in middle-aged and older adults. Middle-aged and older adults with chronic diseases are 36.2% less likely to have high life expectancy than those without chronic diseases. Many different types of chronic diseases are negatively correlated with SLE. Cancer is most negatively correlated with SLE, far exceeding other chronic diseases. Chronic disease and SLE of middle-aged and older adults have age-heterogeneous differences. For middle-aged people aged 45-59 and young older adults aged 60-79, there is a significant correlation between chronic diseases and SLE. However, there is no correlation between chronic diseases and subjective life expectancy in the older population aged 80 and above. The government and society should pay close attention to the prevention and treatment of chronic diseases among middle-aged and older adults and adjust policies and measures according to the population's age structure. In addition, the government and society should pay attention to the spiritual needs of middle-aged and older adults. The government and society should pay more attention to cancer patients. Finally, the scientific research team should also strengthen research on chronic diseases, research and development of specific drugs and vaccines, improve the cure rate of chronic diseases, promote people's health, and make people no longer afraid of diseases.