(1) Objectives: This study aims to investigate the bidirectional relationship between depressive symptoms and cognitive function among older adults in China, addressing a research gap in the context of developing nations. (2) Methods: A total of 3813 adults aged 60 and older participating in 2013, 2015, and 2018 waves of the China Health and Retirement Longitudinal Study (CHARLS) were included. A fixed-effects model and cross-lagged panel model (CLPM) was utilized. (3) Results: First, the results indicated that a significant negative correlation existed between depressive symptoms and cognitive function in older adults during the study period (β = -0.084, p < 0.001). Second, after controlling for unobserved confounding factors, the deterioration and improvement of depressive symptoms still significantly affected cognitive function (β = -0.055, p < 0.001). Third, using the cross-lagged panel model, we observed a reciprocal relationship between depressive symptoms (Dep) and cognitive function (Cog) among Chinese older adults (Dep2013 → Cog2015, β = -0.025, p < 0.01; Dep2015 → Cog2018, β = -0.028, p < 0.001; Cog2013 → Dep2015, β = -0.079, p < 0.01; Cog2015 → Dep2018, β = -0.085, p < 0.01). (4) Discussion: The reciprocal relationship between depressive symptoms and cognitive functioning in older adults emphasizes the need for integrated public health policies and clinical interventions, to develop comprehensive intervention strategies that simultaneously address depressive symptoms and cognitive decline.

Both self-control and self-authenticity are critical to individuals\' mental health and social adjustment, but their relationship has received little attention. Research demonstrates that exerting self-control could help individuals achieve true self and might be promoted by perceiving authenticity. Accordingly, this study utilized a longitudinal design and investigated the temporal relationship between self-control and self-authenticity in a large sample of 2,982 Chinese adolescents (Mage = 17.53, SD = 0.84). Correlation analysis showed that participants possessing higher self-control were associated with greater self-authenticity. Cross-lagged path analysis revealed a reciprocal relationship between self-control and self-authenticity over time. Moreover, bivariate latent change score model indicated that self-control predicted an increase in self-authenticity across time, and vice versa. Overall, this study advances our understanding and suggests that restraining temptation and impulse can promote adolescents\' authenticity, and that the experience of authenticity, in turn, facilitates their self-regulation.

Early studies have shown a relationship between activities of daily living (ADL) disability and depressive symptoms in older people. However, discussions on the direction of this relationship are insufficient. The study\'s objective was to assess the reciprocal relationship between ADL disability and depressive symptoms among middle-aged and older Chinese people.
Data was collected in four waves of a nationwide survey, the China Health and Retirement Longitudinal Study (CHARLS), which was carried out in 2011, 2013, 2015, and 2018. In total, this study included 4,124 participants aged ≥ 45 years at baseline. A summing score of the eleven items for basic activities of daily living (BADL) and instrumental activities of daily living (IADL) was calculated to indicate the degree of ADL disability. The 10-item Centre for Epidemiological Studies Depression Scale (CESD-10) was adopted to measure depressive symptoms. The reciprocal relationship between ADL disability and depressive symptoms was tested by cross-lagged models.
At baseline, 911 (22.1%) participants were classified as having difficulties with ADL, and the prevalence of depressive symptoms was 34.4% (1,418). Among middle-aged and older people in China, there was a significant reciprocal and longitudinal relationship between ADL disability and depressive symptoms. People who had difficulty with ADL faced a higher risk of depressive symptoms, and those who suffered from depressive symptoms were accompanied by an increase in ADL disability in the following years. The subgroup analysis on age also showed that ADL disability was reciprocally and longitudinally related to depressive symptoms. However, only women showed similar results in the subgroup analysis on gender.
This study shows that ADL disability is bi-directionally related to depressive symptoms in middle-aged and older Chinese people over time. The results suggest we should identify ADL disability and bad psychological conditions in time to prevent subsequent mutual damage among middle-aged and older Chinese people, a vulnerable group rising in the future.

This study examined the reciprocal relations between the parenting styles and adolescents\' interpersonal personality in China. A total of 722 sixth-grade Chinese junior high school students reported their interpersonal relatedness (IR) personality trait and perceived parenting styles of their parents. Of these students, 411 completed the survey again in eighth grade. One parent of each student rated their parenting styles. The results indicated that perceived paternal rejection negatively predicted adolescents\' IR 2 years later, whereas perceived paternal behavioral controlling positively predicted adolescents\' IR 2 years later. IR also positively predicted perceived paternal warmth 2 years later. Significant reciprocal association between adolescents\' IR and perceived maternal rejection was found. Parent-rated behavioral control negatively predicted adolescents\' IR, whereas Parent-rated filial piety positively predicted adolescents\' IR. The results were discussed in the Chinese context.

OBJECTIVE: States of vulnerability are multidimensional and become more prevalent with advancing age. These states and the causal relationships between them, merit thorough investigation. This study aimed to understand the reciprocal relationship between the constructs of the locomotive syndrome and social frailty among a community of older adults.
METHODS: This 2-year cohort study examined a community of older adults (≥75 years) consisting of 1177 members. Using Makizako\'s method, social frailty was deemed to be present if more than two out of five questions were answered negatively. Locomotive syndrome was measured with the Geriatric Locomotive Function Scale-25, which consists of 25 items measuring an individual\'s risk of developing locomotive syndrome; a total score of ≥16 identified the presence of locomotive syndrome. Possible reciprocal associations between locomotive syndrome and social frailty were assessed using Cox proportional hazards analyses.
RESULTS: A total of 748 older adults were analyzed in the following subgroups. Among 574 participants without social frailty at the baseline, the presence of locomotive syndrome at the baseline was associated with new-onset social frailty during the next 2 years, after adjusting for confounding factors (hazard ratio 1.76, 95% confidence interval 1.17-2.65). Conversely, the presence of social frailty among participants without locomotive syndrome in the baseline was not associated with new-onset locomotive syndrome.
CONCLUSIONS: The presence of locomotive syndrome was determined to be a risk factor for the onset of social frailty. Therefore, interventions that address the negative impact of locomotive syndrome are a first step toward addressing these vulnerable conditions. Geriatr Gerontol Int 2021; 21: 981-984.

It is well recognized that socioeconomic status (SES) is an important determinant of health, but many studies fail to address the possibility of reverse causation. We aim to investigate the reciprocal relationship between trajectories of SES and health, and how these associations differ by sex. We performed a longitudinal study including 29,824 men and 37,263 women aged 50+ participating in at least two consecutive waves of the Survey of Health, Ageing and Retirement in Europe (SHARE). Using structural equation modeling, we found that baseline household income and wealth led to improvements in cognitive function, grip strength, quality of life and depressive symptoms, and a better initial health led to higher income and wealth for both sexes. However, the results indicated that the relative effect of cognitive function and grip strength on SES trajectories was overall greater than the corresponding effect of SES on health changes, particularly regarding income among women, but for quality of life and depressive symptoms, the reverse was indicated, though most pronounced for the associations with wealth. The reciprocal associations between SES and physical function were stronger for men than for women, whereas most associations with cognitive function and mental health were similar between sexes. This study demonstrates that both social causation and health selection contribute to social inequalities in health, but the influence of each direction and the importance of sex differences may vary according to the health outcomes investigated.

Previous longitudinal studies have found that cognitive function affected oral health, and vice versa. However, research is lacking on the reciprocal relationships between cognitive function and edentulism simultaneously, especially in developing countries. The present study aimed to examine the reciprocal relationship between cognitive function and edentulism among middle-aged and older adults in China.
Data were derived from the 2011 and 2015 waves of the China Health and Retirement Longitudinal Study. The sample included 14,038 respondents aged 45 or older. A two-wave cross-lagged analysis was adopted to test the hypothesized model.
Among respondents aged 45-59, baseline cognitive function was associated with subsequent edentulism [b = -0.017, standard deviation (SD) = 0.006, P < 0.01]. In contrast, baseline edentulism was not significantly associated with poorer cognitive function at the follow-up wave (b = -0.744, SD = 0.383, P > 0.05). However, among respondents aged 60 or older, baseline cognitive function was associated with subsequent edentulism (b = -0.017, SD = 0.005, P < 0.01), and baseline edentulism was also associated with follow-up lower levels of cognitive function (b = -0.419, SD = 0.143, P < 0.01).
These findings demonstrated the reciprocal relationships of cognitive function and edentulism. However, such relationships varied across age groups. This study demonstrates the importance of developing programs and services to promote both cognitive and oral health, especially for those in older age.

Body mass index (BMI) categories and physical fitness are associated but the reciprocal relationship between BMI categories and physical fitness has not been investigated. This study aims to investigate the longitudinal reciprocal relationship between BMI categories and physical fitness.
This is a population-based 4-year cohort study in 48 elementary schools. Children aged 6 to 9 years at recruitment were included. BMI categories and physical fitness including handgrip strength, core muscle endurance, flexibility, and cardiorespiratory fitness were measured using standard equipment and protocol.
Among 26 392 eligible participants, 19 504 (73.9%) were successfully followed for 3 years. Baseline obesity prevalence was 5.9%. After 3 years, those who were unfit at baseline had an increased risk of obesity (risk ratio [RR] 1.41, 95% CI 1.16-1.71, P < .001) and those who were fit at baseline had a decreased risk of obesity (RR 0.69, 95% CI 0.60-0.80, P < .001) compared with moderately fit children. Furthermore, improvement of fitness predicted decreased risk of obesity. Similarly, normal body weight also predicted better physical fitness. The path analysis confirmed a strong reciprocal relationship between physical fitness and obesity.
Better physical fitness was prospectively associated with normal weight and vice versa. Physically fit children were more likely to maintain a healthy weight and those with a healthy weight were more likely to be physically fit, which is important for healthy development.

Mastering transcription skills is an important goal in the development of children\'s written language abilities, and handwriting fluency and spelling accuracy are crucial indicators of transcription ability. The current study was a two-year longitudinal study to investigate the reciprocal relationship of handwriting fluency and spelling accuracy. Participants included 123 students living in mainland China, who were tracked from third to fifth grade, and were administered a comprehensive battery of tests including assessments for non-verbal intelligence, phonological awareness, rapid automatized naming, and copying and dictation of Chinese characters. The results showed that: (1) previous handwriting fluency predicted subsequent spelling accuracy; and (2) previous spelling accuracy predicted subsequent handwriting fluency. These findings indicated there is a bidirectional relationship between handwriting fluency and spelling accuracy in Chinese. This implies spelling accuracy should not be unilaterally emphasized when teaching children new vocabulary, but attention should also be given to the cultivation of handwriting fluency in daily pedagogical practice.

The direction of the longitudinal relationship between physical activity (PA) and fundamental motor skills (FMS) remains unclear. We evaluated the bi-directional, prospective relationships between intensity-specific physical activity (PA) and domain-specific fundamental motor skills (FMS) over 2 years in children attending preschool at baseline.
A sample of 230 children (mean age at baseline 4.7 yr, 52% boys) from the \'Sogn og Fjordane Preschool Physical Activity Study\' was measured 2 years apart. PA was assessed using ActiGraph accelerometers (GT3X+). FMS were evaluated by a test battery guided by the \'Test of Gross Motor Development 3\' and the \'Preschooler Gross Motor Quality Scale\'. PA outcomes were total PA (TPA [counts per minute]) and intensity specific PA and sedentary behaviour (SED) (min/day). FMS outcomes were locomotor, object control, and balance skills. Linear mixed model adjusting for potential co-variates was used to evaluate the bi-directional prospective associations between these variables, including the moderating effect of sex and age.
Baseline total PA, moderate-to-vigorous PA (MVPA), and vigorous PA predicted higher locomotor, object control, and balance skills at follow-up (standardized regression coefficient (β): 0.17 to 0.26, p = 0.002-0.017). Baseline SED predicted lower locomotor skills at follow-up (β: - 0.27, p = 0.012). Baseline light PA did not predict FMS at follow-up. Baseline FMS were not associated with PA or SED at follow-up.
MVPA was positively associated with development of FMS in young children. In contrast, FMS were not related to future PA levels. Our results suggest promotion of MVPA is important for FMS development in young children.