Paying attention to the physical and mental health of Chinese older adults is of great significance for promoting the implementation of the National Strategy for Actively Responding to Population Ageing and the Healthy China strategy. By applying the fixed effect model and cross-lagged panel model to the data of the China Health and Retirement Longitudinal Study (CHARLS) 2013, 2015, and 2018, this paper analyzes the causal relationship between physical disability and depressive symptoms among Chinese older adults. The results show that there is a significant positive correlation between physical disability and depressive symptoms during the same period. After controlling for unobserved confounding factors, the deterioration and improvement of physical disability will significantly affect changes in depressive symptoms. Using the cross-lagged panel model, we found a bidirectional causal relationship between physical disability and depressive symptoms among older adults. By utilizing three physical disability measurement indices, namely the Nagi Index, IADL Index, and ADL Index, it was discovered that the bidirectional causal relationship between them remains significant. Therefore, it is necessary to enhance the prevention and rehabilitation of physical disability among Chinese older adults and to construct a comprehensive health service system for older adults that encompasses various aspects, including physical and mental health.

The population ageing combined with the development of digital information makes it more difficult for older people to integrate into the digital life. In this context, it is urgent to build a system to govern the digital divide faced by older adults. An analysis framework was constructed for the governance of the digital gap faced by older adults from the theoretical perspective of the digital gap and knowledge gap. The specific manifestations, root causes, and possible adverse consequences of digital access gap, usage gap, and knowledge gap were analyzed one by one. It was made clear that the governance of the digital divide faced by older adults should be peopleoriented, focusing on both technical efficiency and social benefits. The major concepts should include participatory governance, inclusive governance, allround governance, and sustainable governance. The primary objective is to generally eliminate the digital information threshold, make all older adults enjoy fair development, and comprehensively help them integrate into the digital society. Approaches and strategic ideas for the governance of the digital divide faced by older adults are also further elaborated.

There has been an agreement among international communities that social participation of the elderly people can actively cope with the issue of population ageing.However,most of the previous studies mainly focus on how social participation affecting health,little attention has been paid to the bi-directional relationship between the.Using the data of the Chinese Longitudinal Healthy Longevity Survey ( CLHLS) ,this paper explores this question using the logit and fixed effect models.After controlling for confounding factors,the model results show that there does exist significant bi-directional relationship between self-report health ( SRH) and social participation of the Chinese elderly.It is suggested that those older adults who report good SRH have a 22.0% ～ 40.1% higher odds ratio of engaging in social participation than those who have poor SRH; older adults who are engaged in social participation have a 16.4% ～ 25.6% higher odds ratio of reporting good SRH; the influence of SRH on social participation might be larger than that of social participation on SRH．Besides,the results reveal that the impact of social participation on SRH is more effective among elderly who report good SRH at baseline．

According to the 2011 － 2012 wave data of Chinese Longitudinal Healthy Longevity Survey (CLHLS) ，passive smoking influences all life stages of Chinese elderly. Not only the prevalence of passive smoking is high in elderly's lives，but also the duration is quite long. From the perspective of individual's life course，this study shows that current passive smoking at home or public places，and passive smoking during childhood as well as young-or middle-ages increases the elderly's risk of depression; current passive smoking at home has an adverse effect on self-reported health. Meanwhile，passive smoking at home during childhood，young- or middle-ages and currently passive smoking at public places substantially increases the elderly's risk of daily life ability impairment . Moreover，passive smoking during young-or middle-ages as well as currently at public places increases the odds of self-reported chronic diseases. Finally，the positive relationship between passive smoking at public places and cognitive function may just reflect a selective effect of cognitive function on social participation at public places.

Based on estimating the rate of ageing by calculating the change of frailty index of the Chinese oldest-old over time,this study concludes that the density distribution of rate of ageing looks like a cone with high proportion of samples converging the mean rate of ageing while the mean rates of ageing for the elderly at different ages are nearly the same,almost 2%-2.5% per year.The regression results show that all of the regression models of both early and present variables can explain at most 16% of the change of individual rate of ageing,which indirectly means that both the early experience and present status are not the main determinants of individual rate of ageing.Moreover,doing regular exercise both in early life and in present life,the adequacy of medical service if seriously ill and sufficiency of financial support for daily costs are helpful for the elderly to slow the rate of ageing,while most postulated determinants of rate of ageing are not tested statistically significantly in this study,including the birth place,current residcence,marriage times,availability of medical service both at around age 60 and in childhood,and experience of hunger in childhood.

Drawing upon data from Chinese Longitudinal Healthy Aging Survey from 1998 to 2005 and using Cox hazard regression model,this paper analyzes impact of religious attendance on mortality risk of the Chinese oldest old,and examines the roles of physical/mental health,healthy behaviors and socioeconomic supports in this relationship,in order to test four types of theoretical models in the literature.The results show that religious attendance is correlated with mortality risk.However,the effects of other potential explanatory variables can reduce the association.The findings suggest that religious attendance may represent a proxy for physical health,especially among the oldest old.

 As the most populous country in the world,population issues have always been a tremendous challenge in the process of sustainable economic and social development in China. The theoretical proposition of "building a population-balanced society" becomes the new growing point of population theories with Chinese characteristics,and has great significance both in theory and practice. In this paper,we discuss the issues of population-balanced society from the perspectives of theory,existing dilemma and policy solutions.