Background: Understand the current situation of social activities among older adults and its impact on mental health, providing policy basis and intervention measures to improve the mental health of the older adult.Method: Collect relevant data from 8,181 older adults aged ≥ 60 years old from the 2020 China Health and Retirement Longitudinal Study (CHARLS), constructing an analysis framework for social activities of older adults in China from three aspects: participation in social activities, number of social activities, frequency of social activities, and describe them, then analyzing the impact of social activities on their mental health using OLS and 2SLS regression models. This study also discusses the impact of eight social activities on the mental health of older adult people through subgroup.Result: Among 8,181 older adults aged 60 and above, 3,808 participated in social activities (56.24%), average number of social activities is 0.71, and average frequency of social activities is 1.31 times. The average score of mental health level measured by CES-D is 15.24 points. Participate in social activities can reduce the depression level of the older adult (β = −0.352, 95%CI: −0.547~−0.158); the more social activities the older adult participate in, the lower the depression level of the older adult (β = −0.214, 95%CI: −0.313~−0.115); the higher the frequency of participating in social activities, the lower the depression level of the older adult (β = −0.133, 95%CI: −0.182~−0.083). In summary, social activities can improve the mental health level of the older adults in China. As for different types of social activities, visiting and socializing with friends, participating in club organization activities, playing mahjong, chess, cards, or going to community activity rooms and attending school or training courses can improve the mental health of the older adult.Discussion: The social activities in three dimensions among older adults in China need to be further improved, and participating in social activities can help improve their mental health. The conclusion provides important policy implications for encouraging and supporting older adults to participate in various social activities, increasing the number and frequency of older adult social activities, then help improving the mental health level of older adults.

Given the ‘subsistence’ character of smallholder production, agricultural production diversification is often seen as an effective strategy for smallholders to improve their diets’ diversity and nutritional status, yet the existing evidence remains inadequate. The study applies bibliometric data from the “Web of Science” database to synthesize 46 papers from developing countries to explore the relationship between production diversity, dietary diversity, and nutrition in smallholder households. The study identifies the most influential journals, authors, organizations, and countries and reveals research themes related to agricultural production and food security. This data analysis can help researchers target potential collaborators and access influential literature in agricultural production diversity and dietary diversity research. In addition, the results showed that agricultural production diversity potentially influences households’ dietary diversity, with mixed results: Agricultural production diversification is the primary way to improve food and nutritional security among smallholder families with low socio-economic status, inaccessible transportation, and poverty; market access and trade have more potential to improve dietary diversity among smallholder households with well-developed markets and higher income levels; the significant measures of agricultural production diversity include Crop Counts, FGPD, SI, and SWDI; the significant measures of dietary diversity include HDDS and IDDS. This paper provides a roadmap for agricultural production and food security researchers by conducting a systematic review of the literature, summarizing some research methods and perspectives applicable to local socio-economic development.

The key to promoting urbanization in China is to achieve urban integration of migrant peasant workers, and basic public health services may have a potential social impact on the subjective welfare of migrant peasant workers. In this paper, we use data from the China Migrants Dynamic Survey (CMDS) to study the impact of basic public health services on the urban integration of migrant peasant workers. The results show that basic public health services can significantly improve the probability of migrant peasant workers’ urban integration. The conclusions remain robust after mitigating potential endogeneity issues using the propensity score matching method (PSM), the CMP method, and robustness testing by replacing the explanatory variables with the reduced tail treatment. Further research found that the impact of basic public health services on migrant peasant workers’ urban integration is heterogeneous. The urban integration effect of basic public health services is more significant in male, high school and above, migrant peasant workers’ groups. The urban integration effect of basic public health services gradually increases with upgrading of the urban grade at the second-tier city and higher urban levels, and it also plays a vital role in the urban integration of the migrant peasant workers at the third-tier city and lower urban levels. Our findings also provide an evidence-based policy for China to promote equalizing basic public health services and a path to the urbanization of migrant peasant workers.