Association of diabetes status with cognitive impairment in two Chinese rural communities

Identifying Predictive Risk Factors for Future Cognitive Impairment Among Chinese Older Adults: Longitudinal Prediction Study

Background

The societal burden of cognitive impairment in China has prompted researchers to develop clinical prediction models aimed at making risk assessments that enable preventative interventions. However, it is unclear what types of risk factors best predict future cognitive impairment, if known risk factors make equally accurate predictions across different socioeconomic groups, and if existing prediction models are equally accurate across different subpopulations.

Objective

This paper aimed to identify which domain of health information best predicts future cognitive impairment among Chinese older adults and to examine if discrepancies exist in predictive ability across different population subsets.

Methods

Using data from the Chinese Longitudinal Healthy Longevity Survey, we quantified the ability of demographics, instrumental activities of daily living, activities of daily living, cognitive tests, social factors and hobbies, psychological factors, diet, exercise and sleep, chronic diseases, and 3 recently published logistic regression-based prediction models to predict 3-year risk of cognitive impairment in the general Chinese population and among male, female, rural-dwelling, urban-dwelling, educated, and not formally educated older adults. Predictive ability was quantified using the area under the receiver operating characteristic curve (AUC) and sensitivity-specificity curves through 20 repeats of 10-fold cross-validation.

Results

A total of 4047 participants were included in the study, of which 337 (8.3%) developed cognitive impairment 3 years after baseline data collection. The risk factor groups with the best predictive ability in the general population were demographics (AUC 0.78, 95% CI 0.77-0.78), cognitive tests (AUC 0.72, 95% CI 0.72-0.73), and instrumental activities of daily living (AUC 0.71, 95% CI 0.70-0.71). Demographics, cognitive tests, instrumental activities of daily living, and all 3 recreated prediction models had significantly higher AUCs when making predictions among female older adults compared to male older adults and among older adults with no formal education compared to those with some education.

Conclusions

This study suggests that demographics, cognitive tests, and instrumental activities of daily living are the most useful risk factors for predicting future cognitive impairment among Chinese older adults. However, the most predictive risk factors and existing models have lower predictive power among male, urban-dwelling, and educated older adults. More efforts are needed to ensure that equally accurate risk assessments can be conducted across different socioeconomic groups in China.

Cognition and BDNF levels in prediabetes and diabetes: A mediation analysis of a cross-sectional study

AIM

Clinical and epidemiological studies suggest links between dementias and Type 2 diabetes (T2DM). The underlying mechanisms of diabetes-related cognitive impairment are largely unknown. This study aims to investigate the role of BDNF in cognitive impairment in prediabetes and T2DM.

METHODS

The study included 68 patients with prediabetes (preDM), 96 patients with T2DM, and 65 healthy controls. The cognitive function of the patients was evaluated with the Montreal Cognitive Assessment (MoCA) test and serum BDNF levels were measured by Elisa. The MoCA scores and BDNF levels were compared between diabetes groups after adjusting for age, gender, and education using ANCOVA. The role of BDNF in the diabetes-related cognitive impairment was investigated through mediation analysis.

RESULTS

Patients with T2DM had significantly lower cognitive performance, particularly in memory. Diabetes was found to be a predictor of both cognitive impairment and BDNF levels. A significant increase in serum BDNF levels was observed in patients with T2DM. However, the mediator role of BDNF in the pathology of cognitive impairment in diabetes was not determined.

CONCLUSION

Cognitive impairment is prevalent in patients with T2DM and should be included in routine screening for complications. The results of the mediation analysis suggest that although BDNF is a biomarker affected by T2DM and cognition, it does not play a mediator role between cognitive impairment and diabetes.

Association of β-cell function and cognitive impairment in patients with abnormal glucose metabolism

Background

Insulin has been demonstrated to play an important role in the occurrence and development of Alzheimer’s disease, especially in those with diabetes. β cells are important insulin-producing cells in human pancreas. This study aimed to investigate the association between β-cell dysfunction and cognitive impairment among patients over 40-year-old with abnormal glucose metabolism in Chinese rural communities.

Methods

A sample of 592 participants aged 40 years or older from the China National Stroke Prevention Project (CSPP) between 2015 and 2017 were enrolled in this study. Abnormal glucose metabolism was defined when hemoglobin Alc ≥ 5.7%. Cognitive function was assessed by the Beijing edition of the Montreal Cognitive Assessment scale. Homeostasis assessment of β-cell function was performed and classified into 4 groups according to the quartiles. A lower value of HOMA-β indicated a worse condition of β-cell function. Multivariate logistic regression was used to analyze the association between β-cell function and cognitive impairment.

Results

In a total of 592 patients with abnormal glucose metabolism, the average age was 60.20 ± 7.63 years and 60.1% patients had cognitive impairment. After adjusting for all potential risk factors, we found the first quartile of β-cell function was significantly associated with cognitive impairment (OR: 2.27, 95%CI: 1.32–3.92), especially at the domains of language (OR: 1.64, 95%CI: 1.01–2.65) and abstraction (OR: 2.29, 95%CI: 1.46–3.58).

Conclusions

Our study showed that worse β-cell function is associated with cognitive impairment of people over 40-year-old with abnormal glucose metabolism in Chinese rural communities, especially in the cognitive domains of abstraction and language.

Association between hemoglobin A1c and asymptomatic carotid intima-media thickness in middle-aged and elderly populations without diabetes

BACKGROUND AND AIMS

Carotid atherosclerosis, including carotid artery intima-media thickness, plaques, and stenosis, is an important risk factor for stroke. However, the association between hemoglobin A1c (HbA1c) and carotid intima-media thickness (cIMT) was inconsistent. The aim of this study was to explore the association between HbA1c and the risk of increased cIMT among the Chinese population aged ≥40 years without diabetes.

METHODS AND RESULTS

A total of 3528 participants without diabetes from the China National Stroke Screen Survey program were enrolled in this study. cIMT was measured using duplex ultrasound examination. Logistic regression models were used to assess the association between HbA1c level and the risk of increased cIMT. A total of 565 (16.0%) participants had increased cIMT. After adjustment for other potential confounding factors, higher levels of HbA1c increased the risk of increased cIMT compared with the lowest level, and the odds ratios for quartile 2, quartile 3, and quartile 4 were 1.58, 1.67, and 1.98, respectively. Age had an interaction impact on the association between HbA1c level and the risk of increased cIMT.

CONCLUSION

In this large-scale and cross-sectional study, high-normal HbA1c was associated with the risk of increased asymptomatic cIMT in a rural Chinese population without diabetes, especially in individuals aged <60 years.

The Association between Social Support and Cognitive Impairment among the Urban Elderly in Jinan, China

China is currently facing a severe challenge of population ageing. However, no study has specifically explored the association between social support and cognitive impairment in Chinese urban elderly aged 60 and older. We explored the prevalence of cognitive impairment and its relationship with social support among the urban elderly aged above 60 years in Jinan, China. A total of 522 urban elderly individuals were recruited using multi-stage cluster random sampling, of which 35.55% were males and 64.45% were females. The average age of all participants was 69.66 ± 8.91 years old. Social support was assessed using the Social Support Rating Scale. Cognitive status was assessed using the Mini-Mental State Examination. Data were collected through face-to-face interviews using structured questionnaires. Descriptive analysis, chi-square tests, and logistic regression analyses were conducted. After analysing the data from 512 participants, 154 (30.1%), 352 (68.8%), and 6 (1.2%) participants had high, moderate, and low levels of social support, respectively. In addition, 125 participants (24.4%) had a cognitive impairment, while the other 387 participants (75.6%) had a normal cognitive status. Binary logistic regression analyses showed that age, educational level, occupation or pre-retirement occupation, and social support were statistically associated with cognitive impairment. A significant association between social support and cognitive impairment was found among the urban elderly in Jinan, China, which provided useful information for the intervention of cognitive impairment. More attention should be paid to the social support of the urban elderly to effectively reduce the occurrence of cognitive impairment.