Epidemiology and Risk Factors for Dementia

Relative associations of behavioral and physiological risks for cardiometabolic disease with cognition in bipolar disorder during mid and later-life: findings from the UK biobank

BACKGROUND

Cardiometabolic disease risk factors are disproportionately prevalent in bipolar disorder (BD) and are associated with cognitive impairment. It is, however, unknown which health risk factors for cardiometabolic disease are relevant to cognition in BD. This study aimed to identify the cardiometabolic disease risk factors that are the most important correlates of cognitive impairment in BD; and to examine whether the nature of the relationships vary between mid and later life.

METHODS

Data from the UK Biobank were available for 966 participants with BD, aged between 40 and 69 years. Individual cardiometabolic disease risk factors were initially regressed onto a global cognition score in separate models for the following risk factor domains; (1) health risk behaviors (physical activity, sedentary behavior, smoking, and sleep) and (2) physiological risk factors, stratified into (2a) anthropometric and clinical risk (handgrip strength, body composition, and blood pressure), and (2b) cardiometabolic disease risk biomarkers (CRP, lipid profile, and HbA1c). A final combined multivariate regression model for global cognition was then fitted, including only the predictor variables that were significantly associated with cognition in the previous models.

RESULTS

In the final combined model, lower mentally active and higher passive sedentary behavior, higher levels of physical activity, inadequate sleep duration, higher systolic and lower diastolic blood pressure, and lower handgrip strength were associated with worse global cognition.

CONCLUSIONS

Health risk behaviors, as well as blood pressure and muscular strength, are associated with cognitive function in BD, whereas other traditional physiological cardiometabolic disease risk factors are not.

Protective Effects Against Dementia Undergo Different Statin Type, Intensity, and Cumulative Dose in Older Adult Type 2 Diabetes Mellitus Patients

OBJECTIVES

This study investigated the relationship between statin use and dementia risk in older adults with type 2 diabetes (T2DM). It also assessed the impact of various statin types, dosage intensity, and cumulative doses on dementia risk.

DESIGN

Employing the inverse probability of treatment weighting (IPTW) Cox hazards model, this research explored the influence of statin utilization on dementia incidence.

SETTING AND PARTICIPANTS

The study included older adult T2DM patients aged 60 years or older who received statins (case group) and those who did not (control group) during the follow-up period.

METHODS

The IPTW Cox hazards model quantified the association between statin use and dementia incidence. Subgroup analyses investigated different statin types, usage intensity, and cumulative dose-dependent relationships with dementia risk, measured by adjusted hazard ratios (aHRs) with corresponding 95% CIs.

RESULTS

Statin users experienced a significant reduction in dementia risk (aHR: 0.47, 95% CI: 0.46-0.48). Subgroup analysis using IPTW Cox regression revealed varying dementia incidence reductions among users of different statin types, with aHRs (95% CIs) ranging from 0.09 to 0.69. Multivariate analyses unveiled a dose-dependent relationship, showing reduced dementia incidence based on cumulative defined daily doses (cDDDs) per year. The corresponding aHRs (95% CIs) were 0.20 to 0.72 across quartiles 4 to 1 of cDDD-years, with a significant trend (P < .001). The optimal daily statin use was 0.88 defined daily doses (DDDs), associated with the lowest dementia risk.

CONCLUSIONS AND IMPLICATIONS

Statins significantly reduced dementia risk in older adult T2DM patients. Higher cumulative defined daily doses (cDDD-years) were linked to more substantial risk reductions. This research underscores the clinical benefits of statin use in preventing dementia in this population and calls for further investigation into the underlying mechanisms. It also raises the possibility of influencing policy decisions to manage dementia risk in this vulnerable group.

Associations of sleep duration and daytime sleepiness with plasma amyloid beta and cognitive performance in cognitively unimpaired, middle-aged and older African Americans

STUDY OBJECTIVES

Given the established racial disparities in both sleep health and dementia risk for African American populations, we assess cross-sectional and longitudinal associations of self-report sleep duration (SRSD) and daytime sleepiness with plasma amyloid beta (Aβ) and cognition in an African American (AA) cohort.

METHODS

In a cognitively unimpaired sample drawn from the African Americans Fighting Alzheimer's in Midlife (AA-FAiM) study, data on SRSD, Epworth Sleepiness Scale, demographics, and cognitive performance were analyzed. Aβ40, Aβ42, and the Aβ42/40 ratio were quantified from plasma samples. Cross-sectional analyses explored associations between baseline predictors and outcome measures. Linear mixed-effect regression models estimated associations of SRSD and daytime sleepiness with plasma Aβ and cognitive performance levels and change over time.

RESULTS

One hundred and forty-seven participants comprised the cross-sectional sample. Baseline age was 63.2 ± 8.51 years. 69.6% self-identified as female. SRSD was 6.4 ± 1.1 hours and 22.4% reported excessive daytime sleepiness. The longitudinal dataset included 57 participants. In fully adjusted models, neither SRSD nor daytime sleepiness is associated with cross-sectional or longitudinal Aβ. Associations with level and trajectory of cognitive test performance varied by measure of sleep health.

CONCLUSIONS

SRSD was below National Sleep Foundation recommendations and daytime sleepiness was prevalent in this cohort. In the absence of observed associations with plasma Aβ, poorer self-reported sleep health broadly predicted poorer cognitive function but not accelerated decline. Future research is necessary to understand and address modifiable sleep mechanisms as they relate to cognitive aging in AA at disproportionate risk for dementia.

CLINICAL TRIAL INFORMATION

Not applicable.

Case report: Successful autologous hematopoietic stem cell transplantation in a patient with GAD antibody-spectrum disorder with rapidly progressive dementia

The prevalence of neurological syndromes associated with antibodies to glutamic acid decarboxylase is increasing. While cognitive impairment is a common feature of this condition, it seldom emerges as the primary symptom. In this study, we discuss a case of refractory dementia associated with the glutamic acid decarboxylase spectrum disorder. Interestingly, this case showed a favorable outcome following autologous hematopoietic stem cell transplantation. We also provide an in-depth review of the current literature on the use of this therapeutic approach for the treatment of this disease.

Relationship between left-behind status and cognitive function in older Chinese adults: a prospective 3-year cohort study

Background

Due to the inaccuracy of the traditional geographical distance-based definition of left-behind status, data on the negative effect of left-behind status on cognitive function among older adults are controversial.

Aims

This study examined the cross-sectional and longitudinal associations of left-behind status with cognitive function in older Chinese adults. The left-behind status definition was based on the frequency of face-to-face parent-child meetings.

Methods

Data from a nationally representative sample of 8 682 older adults (60+ years) in 2015 (5 658 left behind and 3 024 non-left behind), of which 6 933 completed the follow-up in 2018, were obtained from the China Health and Retirement Longitudinal Study. Left-behind older adults were broadly defined as those aged 60+ years who had living adult children and saw their children less than once per month. The cognitive function was assessed with a composite cognitive test with higher total scores indicating better cognitive function.

Results

Left-behind older adults had significantly lower cognitive test scores than non-left-behind older adults in both 2015 (11.1 (6.0) vs 13.2 (5.9), t=15.863, p<0.001) and 2018 (10.0 (6.6) vs 12.4 (6.7), t=14.177, p<0.001). After adjusting for demographic factors, lifestyle factors, chronic medical conditions and the baseline cognitive test score (in the longitudinal analysis only), on average, the cognitive test score of left-behind older adults was 0.628 lower than their non-left-behind counterparts in 2015 (t=5.689, p<0.001). This difference in cognitive test scores attenuated to 0.322 but remained significant in 2018 (t=2.733, p=0.006).

Conclusions

Left-behind older Chinese adults have a higher risk of poor cognitive function and cognitive decline than their non-left-behind counterparts. Specific efforts targeting left-behind older adults, such as encouraging adult children to visit their parents more regularly, are warranted to maintain or delay the progression of cognitive decline.

IL-6 Enhances the Negative Impact of Cortisol on Cognition among Community-Dwelling Older People without Dementia

There is growing evidence that high basal cortisol levels and systemic inflammation independently contribute to cognitive decline among older people without dementia. The present cross-sectional study examined (a) the potential synergistic effect of cortisol levels and systemic inflammation on executive function and (b) whether this effect is more prominent among older people with mild cognitive impairment (MCI). A sub-sample of 99 patients with MCI and 84 older people without cognitive impairment (CNI) (aged 73.8 ± 7.0 years) were recruited from a large population-based cohort in Crete, Greece, and underwent comprehensive neuropsychiatric and neuropsychological evaluation and a single morning measurement of cortisol and IL-6 plasma levels. Using moderated regression models, we found that the relation between cortisol and executive function in the total sample was moderated by IL-6 levels (b = −0.994, p = 0.044) and diagnostic group separately (b = −0.632, p < 0.001). Moreover, the interaction between cortisol and IL-6 levels was significant only among persons with MCI (b = −0.562, p < 0.001). The synergistic effect of stress hormones and systemic inflammation on cognitive status appears to be stronger among older people who already display signs of cognitive decline. Targeting hypercortisolemia and inflammation may be a promising strategy toward improving the course of cognitive decline.

α1-Adrenergic Receptors: Insights into Potential Therapeutic Opportunities for COVID-19, Heart Failure, and Alzheimer's Disease

α1-Adrenergic receptors (ARs) are members of the G-Protein Coupled Receptor superfamily and with other related receptors (β and α2), they are involved in regulating the sympathetic nervous system through binding and activation by norepinephrine and epinephrine. Traditionally, α1-AR antagonists were first used as anti-hypertensives, as α1-AR activation increases vasoconstriction, but they are not a first-line use at present. The current usage of α1-AR antagonists increases urinary flow in benign prostatic hyperplasia. α1-AR agonists are used in septic shock, but the increased blood pressure response limits use for other conditions. However, with the advent of genetic-based animal models of the subtypes, drug design of highly selective ligands, scientists have discovered potentially newer uses for both agonists and antagonists of the α1-AR. In this review, we highlight newer treatment potential for α1A-AR agonists (heart failure, ischemia, and Alzheimer's disease) and non-selective α1-AR antagonists (COVID-19/SARS, Parkinson's disease, and posttraumatic stress disorder). While the studies reviewed here are still preclinical in cell lines and rodent disease models or have undergone initial clinical trials, potential therapeutics discussed here should not be used for non-approved conditions.