**6. Conclusions**

The main findings of this study are as follows:


Based on the above research, we propose the following countermeasures:


**Author Contributions:** Conceptualization, W.Z. and J.H.; methodology, M.S.; software, M.S.; validation, W.Z., J.H., M.S. and C.W.; formal analysis, W.Z.; writing—original draft preparation, W.Z.; writing—review and editing, J.H.; project administration, C.W. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Acknowledgments:** Data used for this research were provided by the study entitled "Chinese Longitudinal Longevity Survey" (CLHLS) managed by the Center for Healthy Aging and Development Studies, Peking University.

**Conflicts of Interest:** The authors declare no conflict of interest.
