Background The prevalence of tooth loss varies across the globe among oldest-old individuals. The presence of fewer than 20 teeth in old age was associated with a decrease in people’s health and quality of life. This paper explored the association between socioeconomics, health-related factors, and tooth loss among the population over the age of 80 in China. Methods The tooth loss status of older Chinese adults was collected with a structured questionnaire from the 8th wave of the Chinese Longitudinal Healthy Longevity Survey (CLHLS). A total of 6716 individuals aged 80 years and above were included. Logistic regression was used to assess the association between socioeconomic statuses, dietary intake at approximately 60 years old, health-related factors, and tooth loss. Results Of the 6716 individuals aged 80 years and above, the composition of the group with fewer teeth for both men and women was statistically significant in many ways. Multivariate logistic regression analyses show that for men, being older than 90 years and being ADL disabled (adjusted OR: 1.71, 95% CI: 1.01–2.89) are factors that are significantly and consistently associated with a higher risk of having fewer than 20 teeth, while having a higher household income per capita (adjusted OR: 0.56, 95% CI: 0.32–0.99) decreases the risk. For women, an age of above 95 years, brushing teeth less than once per day (adjusted OR: 1.96, 95% CI: 1.26–3.03), consuming sugar some of the time as opposed to less than once per month at approximately 60 years old (adjusted OR = 1.74, 95% CI: 1.15–2.62), and being ADL disabled (adjusted OR: 1.70, 95% CI: 1.04–2.77) are factors that are significantly associated with the risk of having fewer than 20 teeth. Conclusion The analysis suggests that socioeconomic status, dietary intake in early old age, and ADL capacity are associated with the risk of having fewer teeth for the population aged 80 years and above, and the risk factors vary between sexes.

Background The low birth rates and rapid population aging has drawn considerable attention from scholars and policymakers in China and around the world. In 2021, China launched the policy and supportive measures that allow up to 3 children per couple. This study aims to explore the influencing factors of the third-child fertility intention among women aged 20–34 years in China. Methods We draw data from the National Fertility Survey conducted in 2017. The nationally representative survey adopts a stratified, 3-stage, and probabilities proportional to size sampling method. A total of 61,588 valid samples aged 20–34 years old were obtained. Fertility desire and behavior, childbearing and service use, and potential influencing factors of fertility intention such as the history of pregnancy were assessed. Results In general, 5.01% of Chinese women of prime childbearing age had fertility intention for a third child, and the proportion varies by region across mainland China. Individual characteristics such as being ethnic minorities, being rural residents, and having more siblings are significantly positively correlated with the third-child fertility intention, while the intention was significantly lower among women with a higher income or education level, migrant women, and those engaged in the non-agricultural labor force. Women who already had a son had lower fertility intention for a third child. Moreover, it was the perceived acceptable costs of childcare services rather than the actual costs that mattered more for the fertility intention. Conclusions Our study concludes a series of socioeconomic factors, and previous childbearing and childrearing experiences are crucial for women’s fertility intention for a third child. These findings highlight the importance of launching supportive measures in addition to the introduction of the 3-child policy in promoting a fertility-friendly society.