Characteristics of the cognitive function transition and influencing factors among Chinese older people: An 8-year longitudinal study

Closing the gap in dementia research by community-based cohort studies in the Chinese population

China accounts for 1/5 of the global population and China faces a particularly heavy dementia burden due to its rapidly ageing population. Unique historical events, genetic background, sociocultural factors, lifestyle, and the COVID-19 pandemic further influence cognitive outcomes in the Chinese population. We searched PubMed, Web of Science, and Embase for community-based cohort studies related to dementia in the Chinese population, and summarized the characteristics, methodologies, and major findings published over the last 25 years from 39 cohorts. We identified critical research gaps and propose future directions, including enhancing sample representativeness, investigating China-specific risk factors, expanding exposure measurements to the whole life-span, collecting objective data, conducting administer-friendly domain-specific cognitive assessments, adopting pathological diagnostic criteria, standardizing biobank construction, verifying multi-modal biomarkers, examining social and genetic-environmental aspects, and monitoring post-COVID cognitive health, to approach high quality of dementia studies that can provide solid evidence to policy making and promote global brain health research.

Weight-adjusted waist index and disability: a cohort study from CHARLS

BACKGROUND

The association between weight-adjusted waist index (WWI) and disability is unclear. This study aimed to assess the relationship between WWI and disability in middle-aged and elderly Chinese individuals and provide more predictive indicators for disability prevention.

METHODS

In this study, 13,015 middle-aged and older adults aged 45 years and above who were surveyed in 2011 by the China Health and Aging Tracking Survey (CHARLS) database were selected, and 8344 respondents with complete data were included for cohort analysis after seven years of follow-up. Information on clinical demographic characteristics, anthropometric indices, assessment of disability, and related covariates were collected, and the presence or absence of disability was assessed by the disability scale. WWI was calculated by dividing the waist circumference (cm) by the square root of the body weight (kg). Cox proportional hazards model was used to analyze the association between WWI and disability after follow-up.

RESULTS

Our study found that 2912 of 8344 participants had disability after seven years of follow-up, and disability incidence was approximately 34.9%. Age, sex, place of residence, chronic disease, depression, waist circumference, and WWI were significantly associated with disability in univariate analysis. Among them, there was a positive association between WWI as a continuous variable and incidence of disability (hazard ratio (HR) = 1.26, 95% CI: 1.22-1.31, p < 0.001). WWI was transformed into categorical variables using quartiles as cutoffs for disability regression analysis. After adjusting covariates, HR values in the 2nd, 3rd and 4th quantile showed an increasing trend compared with the 1st quantile, and the risk of disability among WWI subjects in the 4th quantile increased by 43% (95% CI: 1.24-1.64). P values for the trend test in the model were all < 0.001. In subgroup analyses, the positive association between WWI and risk of disability remained robust for sex, age, alcohol consumption, smoking status, education level, marital status, and place of residence after adjusting for all covariates considered in this study.

CONCLUSIONS

WWI is a new and reliable obesity-related indicator that can be used for disability prevention. WWI can be detected and controlled for reducing the risk of disability.

Relationship between social inequality perception patterns and depressive symptoms among Chinese adults: A national representative longitudinal study

BACKGROUND

The rising prevalence of depressive symptoms presents a pressing global public health concern, exacerbated by prevailing social inequality.

AIM

This study seeks to identify latent profiles of social inequality perception and explore their associations with depressive symptoms.

METHODS

Data were obtained from the China Family Panel Studies (CFPS) involving 10,529 residents aged 18 years and above. Latent profile analysis (LPA) was used to identify different patterns of social inequality perception. Multiple linear regression analysis examined the links between these patterns and depressive symptoms.

RESULTS

Three distinct patterns of social inequality perception were identified: the disappointed pattern (TDP), the neutral pattern (TNP), and the positive pattern (TPP). Perceived social inequality was significantly associated with short-term and long-term depressive symptoms (β = .51, 95% CI [0.29, 0.72] vs. β = .51, 95% CI [0.27, 0.74]). Increases in social inequality perception patterns were also related to more severe depressive symptoms (β = .55, 95% CI [0.36, 0.74]).

CONCLUSIONS

Increasing perceived social inequality is closely linked to elevated depressive symptoms in Chinese adults. This underscores the need for tailored strategies aimed at addressing heightened perceptions of social inequality to reduce the risk of depressive symptoms.

The weight-adjusted waist index and frailty: A cohort study from the China Health and Retirement Longitudinal Study

OBJECTIVES

This cohort study's aim was to assess the association between the weight-adjusted waist index (WWI) and frailty among middle-aged and elderly individuals in China.

METHODS

Seven-year complete follow-up data from 10,349 adults aged ≥45 years, initially surveyed in 2 011 in the China Health and Retirement Longitudinal Study, were analyzed, including clinical demographic characteristics, anthropometric indices, frailty scores, and relevant covariates. The WWI was calculated as waist circumference divided by the square root of the body weight. Frailty was evaluated using the Frailty Index. Relationships between the WWI and frailty were evaluated via Cox proportional hazards modeling. Receiver operating characteristic curve analyses assessed the effectiveness of obesity-related indicators in predicting frailty.

RESULTS

Over a median 84-month follow-up period, frailty occurred in 23.7% (2453/10,349) of participants. After potential confounder adjustment, the WWI positively correlated with frailty (adjusted hazard ratio: 1.14; 95% confidence interval: 1.08-1.20; p < 0.001). After WWI-stratification into quartiles based on frailty and covariate adjustment, regression analyses were conducted; the adjusted hazard ratios exhibited a significant upward trend (p < 0.001). The subgroup analyses revealed higher positive correlations between the WWI and frailty in males and those aged ≥65 years and lower correlations in those with a high school or higher educational level and in married or cohabiting individuals. The strong positive correlation was unaltered in the other subgroup analyses. The WWI outperformed all other obesity-related indicators as a frailty predictor.

CONCLUSIONS

The WWI is a dependable and innovative obesity-related predictor of frailty and could help in mitigating its development.

Social support and cognitive function in Chinese older adults who experienced depressive symptoms: is there an age difference?

Objective

This study examined the moderating effect of overall social support and the different types of social support on cognitive functioning in depressed older adults. We also investigated whether the moderating effect varied according to age.

Methods

A total of 2,500 older adults (≥60 years old) from Shanghai, China were enrolled using a multistage cluster sampling method. Weighted linear regression and multiple linear regression was utilized to analyze the moderating effect of social support on the relationship between depressive symptoms and cognitive function and to explore its differences in those aged 60-69, 70-79, and 80 years and above.

Results

After adjusting for covariates, the results indicated that overall social support (β = 0.091, p = 0.043) and support utilization (β = 0.213, p < 0.001) moderated the relationship between depressive symptoms and cognitive function. Support utilization reduced the possibility of the cognitive decline in depressed older adults aged 60-69 years (β = 0.310, p  < 0.001) and 80 years and above (β = 0.199, p  < 0.001), while objective support increased the possibility of cognitive decline in depressed older people aged 70-79 years (β = -0.189, p  < 0.001).

Conclusion

Our findings highlight the buffering effects of support utilization on cognitive decline in depressed older adults. We suggest that age-specific measures should be taken when providing social support to depressed older adults in order to reduce the deterioration of cognitive function.