Background Previous studies reported the value of blood-based biomarkers in predicting Alzheimer disease (AD) progression among individuals with different disease stages. However, evidence regarding the value of these markers in those with amnestic mild cognitive impairment (aMCI) is insufficient. Methods A cohort with 251 aMCI individuals were followed for up to 8 years. Baseline blood biomarkers were measured on a single-molecule array platform. Multipoint clinical diagnosis and domain-specific cognitive functions were assessed to investigate the longitudinal relationship between blood biomarkers and clinical AD progression. Results Individuals with low Aβ42/Aβ40 and high p-tau181 at baseline demonstrated the highest AD risk (hazard ratio = 4.83, 95% CI 2.37–9.86), and the most dramatic decline across cognitive domains. Aβ42/Aβ40 and p-tau181, combined with basic characteristics performed the best in predicting AD conversion (AUC = 0.825, 95% CI 0.771–0.878). Conclusions Combining Aβ42/Aβ40 and p-tau181 may be a feasible indicator for AD progression in clinical practice, and a potential composite marker in clinical trials.

Background: Lives of older adults have been greatly affected by the COVID-19 pandemic. Methods: A telephone survey was conducted among the older adults aged 60 and above who lived in downtown Shanghai. We compared the lifestyle, mood, and disease management of older adults before and during the COVID-19 pandemic. Results: One hundred and fifty-six older adults in Shanghai completed the survey. The proportions of older adults with adequate consumption of meat (49.4% vs. 53.1%, P=0.0339) and eggs (73.7% vs. 77.6%, P=0.0143) were significantly higher than before. Participants spent significantly more time on housework (median: 2.0, IQR:1.0-3.0 vs. median: 2.0, IQR:1.0-2.0 hours/day; P=0.0361) and leisure activities (median: 7.0, IQR: 5.0-8.6 vs. median: 6.0, IQR: 4.0-8.5 hours/day; P<0.0001) during the pandemic than before. More participants developed new hobbies (27.6% vs. 36.5%, P=0.0470) and learned new skills (5.1% vs. 19.9%, P<0.0001). However, the number of participants routinely self-testing blood glucose and/or blood pressure decreased from 77.6% before to 64.1% during the pandemic (P=0.0002). Conclusions: The COVID-19 pandemic affected the lifestyle, mood, and chronic diseases management among community-dwelling older adults. Supportive measures and interventions need to be tailored to older adults living in the community.

Background: The relationship between body mass index (BMI) and dementia is inconclusive. Undesirable loss of fat-free mass is a risk factor for cognitive decline while obesity is also a risk factor for cardio-metabolic disorders among the older adults. Objective: This study aimed to examine the association between BMI and incident all-cause dementia among Chinese older adults using a prospective study. Methods: Participants were 1,627 community residents aged 60 or older without dementia from the Shanghai Aging Study. Cox regression models, incorporated with restricted cubic splines, were used to explore a nonlinear association between baseline BMI and risk of all-cause dementia as measured by hazard ratio (HR) using both frequentist and Bayesian approach. Results: We diagnosed 136 incident dementia cases during the mean follow-up of 5.3 years. Compared with moderate BMI (18.5–24.0 kg/m2), low BMI (<  18.5 kg/m2) were related to an increased risk of dementia with the HR as 3.38 (95% CI 1.50–7.63), while high BMI (≥24.0 kg/m2) showed a decreased risk of dementia without statistical significance (HR = 0.91, 95% CI 0.60 to 1.39). Sensitivity analysis in participants without central obesity indicated that the association was still significant with even higher HR. Bayesian approach presented the similar results. Conclusion: Our result indicates that low BMI may contribute to high risk of incident dementia, even in individuals without central obesity.

Background: Previous studies indicated that blood-based biomarkers could predict cognitive decline in Alzheimer's disease (AD) continuum.Method: Two hundred and fifty-one participants with amnestic mild cognitive impairment (aMCI) from the Shanghai Memory Study were followed up for a maximum of 8 years. Baseline blood biomarkers were measured with the single-molecule array (Simoa) platform. Multipoint clinical diagnosis and domain-specific cognitive functions were assessed to investigate the longitudinal relationship between blood biomarkers and clinical AD progression.Result: Participants with high-risk plasma Aβ42/Aβ40 (A) and p-tau181 (T) level demonstrated the highest probability of incident AD (HR 5.54, 95% CI 2.99-10.27), and the most dramatic decline in global cognition, attention, executive function, visuospatial function, and language. Comparing to young-old participants, the old-old ones with low-and moderate-risk AT showed higher AD risks (HR 3.70, HR 3.15,, and faster cognitive deterioration. Conclusion:The results supported the use of plasma Aβ42/Aβ40 and p-tau181 as accessible and feasible indicators of AD progression and the long-term cognitive deterioration, especially in patients with older age.

Objective: This study aimed to explore the joint effect of body mass index (BMI) and serum lipids levels on incident dementia. Methods:We prospectively followed up with 1,627 dementia-free community residents aged ≥60 for 5.7 years on average. At baseline, weight,and height were measured, and total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) were detected in serum. Demographic characteristics were collected through questionnaires. Dementia was based on consensus diagnosis of neurologists and neuropsychologists using DSM-IV criteria. A generalized additive model (GAM) was used to assess the exposure-response relationship between BMI and serum lipid levels and dementia risk. Interactions and further classifications of BMI and serum lipid levels were further presentedby bivariate surface models and decision-tree models. Results: The joint effects of TC with BMI, TG with BMI, and LDL-C with BMI on the risk of incident dementia shared a similar pattern, which was different from their independent exposure-response curves. The joint effect of HDL-C with BMI showed an S-surface but without statistical significance. Participants withTC<5.4 andBMI<21 (Hazard Ratio(HR) 1.93, 95% Confidence Interval (CI) 1.05-3.53), TC<5.4 and BMI≥21 (HR 1.73, 95% CI 1.09-2.72), and TC≥5.4 and BMI<21 (HR 4.02, 95% CI 2.10-7.71) were identified to have the increased risk of incident dementia compared to those with TC≥5.4 andBMI≥21. Participants with TG<1.7 and BMI<21 had an increased risk of incident dementia compared to those with TG≥1.7 and BMI≥21 (HR 1.98, 95%CI 1.17-3.3). Participants with LDL-C≥3.3 andBMI<21 were identified to have an increased risk of incident dementia compared to those with LDL-C≥3.3 and BMI≥21 (HR 3.33, 95%CI 1.64-6.78). Conclusions: Our study showed that low BMI combined with low or high levels of serum lipids may increase the risk of dementia among older adults. This finding suggests the potential impacts of these two metabolic indexes on the risk of dementia.