Is Dementia More Fatal Than Previously Estimated? A Population-based Prospective Cohort Study

Causal relationship between dietary salt intake and dementia risk: Mendelian randomization study

OBJECTIVE

Observational research has indicated a potential link between dietary salt intake and susceptibility to dementia. However, it is important to note that these types of studies are prone to the issues of reverse causation and residual confounding. Therefore, we conducted a two-sample Mendelian randomization (MR) study to explore the causality.

METHOD

To explore the causal relationship between them, this Mendelian randomization (MR) study incorporated summary statistics of dietary salt intake and dementia. We estimated the causality between salt intake and the risk of overall dementia and various subtypes of dementia, including Alzheimer's disease (AD), Vascular dementia (VaD), and Lewy body dementia (LBD). The inverse variance-weighted (IVW) method was the major MR analysis. To conduct sensitivity analyses, we employed various MR methods, the pleiotropy residual sum and outlier (MR-PRESSO) method, and the leave-one-out approach. The MR-Egger intercept and Cochran's Q test were conducted to test pleiotropy and heterogeneity respectively.

RESULTS

A suggestive association was observed for genetically predicted higher dietary salt intake and increased risk of overall dementia in the European ancestry [odds ratio (OR): 1.542; 95% confidence interval (95% CI): 1.095-2.169; P = 0.013]. The causal relationship between dietary salt intake and overall dementia is robust with respect to the choice of statistical methods and is validated through extensive sensitivity analyses that guard against various model assumption violations. Meanwhile, no clear heterogeneity or pleiotropy was identified. However, we failed to detect a causal effect of dietary salt intake on the risk of various dementia subtypes.

CONCLUSION

The results of this research present strong evidence that established a significant association between dietary salt intake and the likelihood of developing dementia. These findings reinforce the notion that the amount of dietary salt intake plays a crucial role in determining the risk of acquiring this cognitive condition. By establishing a definitive correlation, this study highlights the importance of reducing salt consumption as a preventive measure against dementia.

Association of periodontal disease treatment with mortality in patients with dementia: a population-based retrospective cohort study (2002-2018)

Dementia is one of the leading causes of death worldwide. In this study, we analyzed the association of periodontal treatment with the risk of death in patients with dementia. The analyzed data were obtained by linking the National Health Insurance Corporation claims data between 2002 and 2018 to the Statistics Korea death registry. In total, 1,131,406 patients with dementia aged ≥ 65 years had undergone dental treatment during the study period. Time-dependent Cox proportional hazards model was performed. The mortality rate was approximately 10% among the patients with dementia. The 17-years cumulative survival rates for patients who received periodontal treatment and their untreated counterparts were 83.5% and 71.5%, respectively. The crude hazard ratio of the periodontal group was approximately twice as high as that of the non-periodontal group (1.99; P < 0.001). Furthermore, in the regression model that was adjusted for socio-demographic variables and systematic chronic diseases, the risk of death in the non-periodontal group was approximately 1.83 times higher than that of the periodontal group (P < 0.00). These findings suggest that preventive periodontal treatment may decrease mortality risk in older people with dementia.

Impact of dementia and drug compliance on patients with acute myocardial infarction

BACKGROUND

In South Korea, the number of people with dementia is rising at a worrisome rate, and many of them also have acute myocardial infarction (AMI), a disease with a high mortality rate.

HYPOTHESIS

We speculated that dementia and drug compliance have significant impact on the mortality of patients with AMI.

METHODS

The study derived data from the National Health Insurance Service-Senior for a retrospective cohort study. The total number of patients diagnosed with AMI for the first time between 2007 and 2013 was 16 835, among whom 2021 had dementia. Medication possession ratio (MPR) was used to assess medication adherence.

RESULTS

AMI patients with dementia had unfavorable baseline characteristics; they had significantly higher risk of all-cause mortality (hazard ratio [HR]: 2.49; 95% confidence interval [CI]: 2.34-2.66; p < .001) and lower MPR (aspirin: 21.9% vs. 42.8%; p < .001). AMI patients were stratified by presence of dementia and medication adherence, and the survival rate was the highest among those with no dementia and good adherence, followed by those with no dementia and poor adherence, those with dementia and good adherence, and those with dementia and poor adherence. The multivariable analysis revealed that dementia (HR: 1.64; 95% CI: 1.53-1.75; p < .001) and poor adherence to medication (HR: 1.60; 95% CI: 1.49-1.71; p < .001) had a significant association with all-cause mortality in AMI patients.

CONCLUSIONS

AMI patients with dementia have a higher mortality rate. Their prognosis is negatively affected by their poorer medication adherence than patients without dementia.

CERAD (Consortium to Establish a Registry for Alzheimer's Disease) Neuropsychology Assessment Battery: 35 Years and Counting

BACKGROUND

In 1986, the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) was mandated to develop a brief neuropsychological assessment battery (CERAD-NAB) for AD, for uniform neuropsychological assessment, and information aggregation. Initially used across the National Institutes of Aging-funded Alzheimer's Disease Research Centers, it has become widely adopted wherever information is desired on cognitive status and change therein, particularly in older populations.

OBJECTIVE

Our purpose is to provide information on the multiple uses of the CERAD-NAB since its inception, and possible further developments.

METHODS

Since searching on "CERAD neuropsychological assessment battery" or similar terms missed important information, "CERAD" alone was entered into PubMed and SCOPUS, and CERAD-NAB use identified from the resulting studies. Use was sorted into major categories, e.g., psychometric information, norms, dementia/differential dementia diagnosis, epidemiology, intervention evaluation, genetics, etc., also translations, country of use, and alternative data gathering approaches.

RESULTS

CERAD-NAB is available in ∼20 languages. In addition to its initial purpose assessing AD severity, CERAD-NAB can identify mild cognitive impairment, facilitate differential dementia diagnosis, determine cognitive effects of naturally occurring and experimental interventions (e.g., air pollution, selenium in soil, exercise), has helped to clarify cognition/brain physiology-neuroanatomy, and assess cognitive status in dementia-risk conditions. Surveys of primary and tertiary care patients, and of population-based samples in multiple countries have provided information on prevalent and incident dementia, and cross-sectional and longitudinal norms for ages 35-100 years.

CONCLUSION

CERAD-NAB has fulfilled its original mandate, while its uses have expanded, keeping up with advances in the area of dementia.

Mortality Risks and Causes of Death by Dementia Types in a Japanese Cohort with Dementia: NCGG-Stories

BACKGROUND

Prognosis-related information regarding dementia needs to be updated, as changes in medical and long-term care environments for patients with dementia in recent decades may be improving the prognosis of the disease.

OBJECTIVE

We aimed to investigate the mortality, cause of death, and prognostic factors by types of dementia in a Japanese clinic-based cohort.

METHODS

The National Center for Geriatrics and Gerontology-Life Stories of People with Dementia consists of clinical records and prognostic data of patients who visited the Memory Clinic in Japan. Patients who attended the clinic between July 2010 and September 2018, or their close relatives, were asked about death information via a postal survey. A cohort of 3,229 patients (mean age, 76.9; female, 1,953) was classified into six groups: normal cognition (NC), mild cognitive impairment (MCI), Alzheimer's disease (AD), vascular dementia, dementia with Lewy bodies (DLB), and frontotemporal lobar degeneration. A Cox proportional hazards model was employed to compare the mortality of each type of dementia, MCI, and NC.

RESULTS

Patients with all types of dementia and MCI had higher mortality rates than those with NC (hazard risks: 2.61-5.20). The most common cause of death was pneumonia, followed by cancer. In the MCI, AD, and DLB groups, older age, male sex, and low cognitive function were common prognostic factors but not presence of apolipoprotein E ɛ4 allele.

CONCLUSION

Our findings suggest important differences in the mortality risk and cause of death among patients with dementia, which will be useful in advanced care planning and policymaking.

Mood disorders increase mortality mainly through dementia: A community-based prospective cohort study

OBJECTIVE

The effects of mood disorders on mortality may be mediated by their effects on the risk of dementia, and interventions to reduce the occurrence of dementia may reduce their overall mortality. This study aimed to investigate the direct effects of depressive and bipolar disorders on the 6-year risk of mortality and also their indirect effects on mortality due to their effect on the risk of dementia.

METHODS

A total of 5101 Koreans were selected from a community-based prospective cohort study, and 6-year risks of mortality and dementia in participants with depressive and bipolar disorders were estimated by Cox proportional hazard analysis. The direct and indirect effects of depressive and bipolar disorders on the risk of mortality were estimated using structural equation modeling.

RESULTS

The depressive and bipolar disorder groups showed 51% and 85% higher 6-year mortality, and 82% and 127% higher risk of dementia, respectively, compared to euthymic controls. The effects of depressive and bipolar disorders on mortality were mainly mediated by their effects on the risk of dementia in a structural equation model. The direct effects of each mood disorder on mortality were not significant.

CONCLUSION

Both depressive and bipolar disorders increased the risks of mortality and dementia, and the effects of mood disorders on mortality were mainly mediated through dementia. As dementia occurs later in life than mood disorders, measures to prevent it may effectively reduce mortality in individuals with a history of mood disorders, as well as being more feasible than attempting to control other causes of death.

Causes of Mortality in Korean Patients with Neurodegenerative Dementia

The prevalence of neurodegenerative dementia is increasing owing to the rapid growth of the older population. We investigated risks and causes of mortality in Korean patients with neurodegenerative dementia using data from the Korean Health Insurance Review and Assessment Service-National Sample Cohort with the aim to improve their care. From a pool of 1,125,691 patients, 11,215 patients aged ≥60 years who were diagnosed with dementia between 2002 and 2013 were examined along with 44,860 matched controls. A Cox proportional hazard model was used to calculate crude and adjusted hazard ratios (HRs). During the follow-up period, 34.5% and 18.8% of individuals in the neurodegenerative dementia and control groups, respectively, died (P < 0.001). The adjusted HR for mortality in the neurodegenerative dementia group was 2.11 (2.41 and 1.96 in men and women, respectively). Moreover, the adjusted HRs in patients with neurodegenerative dementia were 3.25, 2.77, and 1.84 for those diagnosed at ages 60–69, 70–79, and ≥80 years, respectively. The highest odds ratio for mortality was noted among patients with neurologic disease (15.93) followed by those with mental disease (4.89). These data show that the risk of mortality increased regardless of age and sex in Korean patients with neurodegenerative dementia.

FTD-PSP is an Unusual Clinical Phenotype in A Frontotemporal Dementia Patient with A Novel Progranulin Mutation

Progranulin (GRN) mutations are a major cause of frontotemporal dementia (FTD); the spectrum of clinical phenotypes of FTD is much more extensive than previously reported. The frequency and locations of GRN mutations in Chinese patients with FTD remain uncertain. We performed cDNA sequencing in one sporadic male patient who initially presented FTD symptoms. Brain magnetic resonance imaging (MRI) and positron emission computed tomography/computed tomography (PET/CT) were applied to further confirm the diagnosis of FTD from this patient. Cellular apoptosis and survival test were performed to identify the function of GRN. We identified one novel missense GRN mutation (c.1498G>A, p.V500I) in this patient, who initially presented typical behavioral-variant frontotemporal dementia (bvFTD) features but then presented progressive supranuclear palsy (PSP) clinical characteristics 5 years after onset. Besides, WT GRN protein showed an adequate trophic stimulus to preserve the survival of SH-SY5Y cells in the medium free of serum, while GRN mutation (c.1498G>A, p.V500I) may impair the ability of supporting cell survival. This study owns significant implications for genetic counseling and clinical heterogeneity. We illustrate the fact that FTD presenting features of bvFTD and PSP in one patient could be considered as a specific phenotype in patients with GRN mutations. GRN p.V500I led to the neuronal degeneration in vitro; this finding provides a significant evidence that this mutation may be a new causative mutation in patients with FTD.

ZiBuPiYin Recipe Prevented and Treated Cognitive Decline in ZDF Rats With Diabetes-Associated Cognitive Decline via Microbiota-Gut-Brain Axis Dialogue

Gut microbiota is becoming one of the key determinants in human health and disease. Shifts in gut microbiota composition affect cognitive function and provide new insights for the prevention and treatment of neurological diseases. Diabetes-associated cognitive decline (DACD) is one of the central nervous system complications of type 2 diabetes mellitus (T2DM). ZiBuPiYin recipe (ZBPYR), a traditional Chinese medicine (TCM) formula, has long been used for the treatment of T2DM and prevention of DACD. However, the contribution of ZBPYR treatment to the interaction between the gut microbiota and metabolism for preventing and treating DACD remains to be clarified. Here, we investigate whether the gut microbiota plays a key role in ZBPYR-mediated prevention of DACD and treatment of T2DM via incorporating microbiomics and metabolomics, and investigate the links between the microbiota-gut-brain axis interaction and the efficacy of ZBPYR in ZDF rats. In the current study, we found that ZBPYR treatment produced lasting changes in gut microbiota community and metabolites and remotely affected hippocampus metabolic changes, thereby improving memory deficits and reversing β-amyloid deposition and insulin resistance in the brain of ZDF rats from T2DM to DACD. This may be related to a series of metabolic changes affected by gut microbiota, including alanine, aspartic acid, and glutamic acid metabolism; branched-chain amino acid metabolism; short-chain fatty acid metabolism; and linoleic acid/unsaturated fatty acid metabolism. In summary, this study demonstrates that prevention and treatment of DACD by ZBPYR partly depends on the gut microbiota, and the regulatory effects of bacteria-derived metabolites and microbiota-gut-brain axis are important protective mechanisms of ZBPYR.

Link Between Dietary Sodium Intake, Cognitive Function, and Dementia Risk in Middle-Aged and Older Adults: A Systematic Review

Background:

A key focus for dementia risk-reduction is the prevention of socio-demographic, lifestyle, and nutritional risk factors. High sodium intake is associated with hypertension and cardiovascular disease (both are linked to dementia), generating numerous recommendations for salt reduction to improve cardiovascular health.

Objective:

This systematic review aimed to assess, in middle- and older-aged people, the relationship between dietary sodium intake and cognitive outcomes including cognitive function, risk of cognitive decline, or dementia.

Methods:

Six databases (PubMed, EMBASE, CINAHL, Psych info, Web of Science, and Cochrane Library) were searched from inception to 1 March 2020. Data extraction included information on study design, population characteristics, sodium reduction strategy (trials) or assessment of dietary sodium intake (observational studies), measurement of cognitive function or dementia, and summary of main results. Risk-of-bias assessments were performed using the National Heart, Lung, and Blood Institute (NHLBI) assessment tool.

Results:

Fifteen studies met the inclusion criteria including one clinical trial, six cohorts, and eight cross-sectional studies. Studies reported mixed associations between sodium levels and cognition. Results from the only clinical trial showed that a lower sodium intake was associated with improved cognition over six months. In analysis restricted to only high-quality studies, three out of four studies found that higher sodium intake was associated with impaired cognitive function.

Conclusion:

There is some evidence that high salt intake is associated with poor cognition. However, findings are mixed, likely due to poor methodological quality, and heterogeneous dietary, analytical, and cognitive assessment methods and design of the studies. Reduced sodium intake may be a potential target for intervention. High quality prospective studies and clinical trials are needed.

An Effective Brain Imaging Biomarker for AD and aMCI: ALFF in Slow-5 Frequency Band

BACKGROUND

As a potential brain imaging biomarker, amplitude of low frequency fluctuation (ALFF) has been used as a feature to distinguish patients with Alzheimer's disease (AD) and amnestic mild cognitive impairment (aMCI) from normal controls (NC). However, it remains unclear whether the frequency-dependent pattern of ALFF alterations can effectively distinguish the different phases of the disease.

METHODS

In the present study, 52 AD and 50 aMCI patients were enrolled together with 43 NC in total. The ALFF values were calculated in the following three frequency bands: classical (0.01-0.08 Hz), slow-4 (0.027-0.073 Hz) and slow-5 (0.01-0.027 Hz) for the three different groups. Subsequently, the local functional abnormalities were employed as features to examine the effect of classification among AD, aMCI and NC using a support vector machine (SVM).

RESULTS

We found that the among-group differences of ALFF in the different frequency bands were mainly located in the left hippocampus (HP), right HP, bilateral posterior cingulate cortex (PCC) and bilateral precuneus (PCu), left angular gyrus (AG) and left medial prefrontal cortex (mPFC). When the local functional abnormalities were employed as features, we identified that the ALFF in the slow-5 frequency band showed the highest accuracy to distinguish among the three groups.

CONCLUSION

These findings may deepen our understanding of the pathogenesis of AD and suggest that slow-5 frequency band may be helpful to explore the pathogenesis and distinguish the phases of this disease.

Survival Analysis of Patients with Alzheimer's Disease: A Study Based on Data from the Korean National Health Insurance Services' Senior Cohort Database

BACKGROUND

Korea's rapidly aging population has experienced a sharp rise in the prevalence of dementia. Patients with Alzheimer's disease (AD), which is estimated to be about three-quarters of all patients with dementia, tend to have higher mortality rates compared with patients without Alzheimer's disease. In this study, a survival analysis of patients with AD was conducted in order to provide knowledge to those who provide medical care to these patients.

METHODS

Data on individuals over 65 years old in 2004 were extracted from the Korean National Health Insurance Services' Senior Cohort database (2002-2013). The subjects were 209,254 patients, including 2,695 who were first diagnosed with AD (the AD group) and 206,559 that had not been diagnosed with the disease (non-AD group). To investigate the independent effect of AD on survival, the Cox proportional-hazards model, hazard ratios (confidence interval of 95%), and the Kaplan-Meier method were used.

RESULTS

Mean survival time in the AD group was 5.3±3.3 years, which was about 2.5 years shorter than that in the non-AD group (7.8±2.4 years). The mortality rate in the AD group (66.3%) was higher than that in the non-AD group (26.3%). The adjusted hazard ratio in the AD group was 2.5 and, therefore, it was found that the AD group had a 2.5-fold higher risk of death than the non-AD group.

CONCLUSION

Overall, AD has a large, independent impact on survival. Survival time was shorter, and the mortality rate and risk were generally higher in the AD group, compared with the non-AD group.

The Loss in Expectation of Life due to Early-Onset Mild Cognitive Impairment and Early-Onset Dementia in Norway

INTRODUCTION

Whether patients with early-onset dementia have poorer or improved survival compared with those with a late onset largely depends on the survival measure. Survival estimates for early-onset mild cognitive impairment (MCI) diagnosis are particularly scarce. We aimed to estimate life expectancy (LE) in patients with early-onset dementia or early MCI, and loss in expectation of life (LEL) for these groups. Comparisons were made with the general Norwegian population and a subgroup of patients with late-onset dementia.

METHODS

Early onset was defined as receiving a diagnosis of MCI or dementia before age 65 years. LE and LEL were predicted using flexible parametric survival models. Our study population was comprised of newly diagnosed (incident) cases (n = 4,906), aged 50-90 years at the time of diagnosis (672 were diagnosed before age 65 years, of which 291 were diagnosed with dementia), in the Norwegian register of persons assessed for cognitive symptoms (NorCog) between 2009 and 2017, and patients were followed up for mortality or censorship until January 2018.

RESULTS

Among the early-onset patients, 8 and 23% died during follow-up, in the MCI and dementia groups, respectively. Both early-onset MCI and especially early-onset dementia were associated with lower LE than in the general Norwegian population; LE for 60-year-old women in 2016 was 26 years in the general population, 20 years in MCI patients, and 7 years in dementia patients. The corresponding LE at 80 years was 10, 6, and 5 years. Thus, LEL were particularly pronounced for patients with early dementia. The diagnosis-specific LE pattern in men was similar to that in women.

DISCUSSION

Early-onset MCI was associated with substantial life years lost (5-6 years), but the loss was particularly pronounced for those with early-onset dementia, reducing the expected life length by 2 decades.