Cognition, function, and prevalent dementia in centenarians and near-centenarians: An individual participant data (IPD) meta-analysis of 18 studies.

INTRODUCTION: There are limited data on prevalence of dementia in centenarians and near-centenarians (C/NC), its determinants, and whether the risk of dementia continues to rise beyond 100. METHODS: Participant-level data were obtained from 18 community-based studies (N = 4427) in 11 countries that included individuals ≥95 years. A harmonization protocol was applied to cognitive and functional impairments, and a meta-analysis was performed. RESULTS: The mean age was 98.3 years (SD = 2.67); 79% were women. After adjusting for age, sex, and education, dementia prevalence was 53.2% in women and 45.5% in men, with risk continuing to increase with age. Education (OR 0.95;0.92-0.98) was protective, as was hypertension (odds ratio [OR] 0.51;0.35-0.74) in five studies. Dementia was not associated with diabetes, vision and hearing impairments, smoking, and body mass index (BMI). DISCUSSION: Among the exceptional old, dementia prevalence remains higher in the older participants. Education was protective against dementia, but other factors for dementia-free survival in C/NC remain to be understood.

Italian adaptation of the Uniform Data Set Neuropsychological Test Battery (I-UDSNB 1.0): development and normative data.

BACKGROUND: Neuropsychological testing plays a cardinal role in the diagnosis and monitoring of Alzheimer's disease. A major concern is represented by the heterogeneity of the neuropsychological batteries currently adopted in memory clinics and healthcare centers. The current study aimed to solve this issue. METHODS: Following the initiative of the University of Washington's National Alzheimer's Coordinating Center (NACC), we presented the Italian adaptation of the Neuropsychological Test Battery of the Uniform Data Set (I-UDSNB). We collected data from 433 healthy Italian individuals and employed regression models to evaluate the impact of demographic variables on the performance, deriving the reference norms. RESULTS: Higher education and lower age were associated with a better performance in the majority of tests, while sex affected only fluency tests and Digit Span Forward. CONCLUSIONS: The I-UDSNB offers a valuable and harmonized tool for neuropsychological testing in Italy, to be used in clinical and research settings.

Preventive pharmacological treatment in subjects at risk for fatal familial insomnia: science and public engagement.

Engaging patients as partners in biomedical research has gradually gained consensus over the last two decades. They provide a different perspective on health priorities and help to improve design and outcomes of clinical studies. This paper describes the relationship established between scientists and members of a large family at genetic risk of very rare lethal disease, fatal familial insomnia (FFI). This interaction led to a clinical trial based on the repurposing of doxycycline - an antibiotic with a known safety profile and optimal blood-brain barrier passage - which in numerous preclinical and clinical studies had given evidence of its potential therapeutic effect in neurodegenerative disorders, including prion diseases like FFI. The design of this trial posed several challenges, which were addressed jointly by the scientists and the FFI family. Potential participants excluded the possibility of being informed of their own FFI genotype; thus, the trial design had to include both carriers of the FFI mutation (10 subjects), and non-carriers (15 subjects), who were given placebo. Periodic clinical controls were performed on both groups by blinded examiners. The lack of surrogate outcome measures of treatment efficacy has required to compare the incidence of the disease in the treated group with a historical dataset during 10 years of observation. The trial is expected to end in 2023. Regardless of the clinical outcome, it will provide worthwhile knowledge on the disease. It also offers an important example of public engagement and collaboration to improve the quality of clinical science.

MGUS and clonal hematopoiesis show unrelated clinical and biological trajectories in an older population cohort.

Monoclonal gammopathy of undetermined significance (MGUS) and clonal hematopoiesis (CH) are 2 preclinical clonal expansions of hematopoietic cells whose prevalence rises with age, reaching almost 10% in people of aged 70 years and older. The increased risk of myeloid malignancies in patients with myeloma is well defined, and the study of the association between CH and MGUS could help explain this phenomenon. Here, we analyzed a fully clinically annotated dataset of 777 older subjects (median age, 91 years) previously screened for prevalence of CH. The prevalence of MGUS and CH was 9.6% and 17.3%, respectively. We detected CH in 9.7% of the patients with MGUS and MGUS in 5.5% of the patients with CH. We did not find a significant correlation between the presence of MGUS and CH. Furthermore, the 2 conditions showed a differential association with clinical and laboratory covariates, suggesting that MGUS and CH may represent age-associated unrelated clonal drifts of hematopoietic cells. Confirmatory studies are needed to assess the relevance of CH in plasma cell disorders. This trial was registered at www.clinicaltrials.gov as #NCT03907553.

Mild anemia and 11- to 15-year mortality risk in young-old and old-old: Results from two population-based cohort studies.

BACKGROUND: Mild anemia is a frequent although often overlooked finding in old age. Nevertheless, in recent years anemia has been linked to several adverse outcomes in the elderly population. Objective of the study was to investigate the association of mild anemia (hemoglobin concentrations: 10.0-11.9/12.9 g/dL in women/men) with all-cause mortality over 11-15 years and the effect of change in anemia status on mortality in young-old (65-84 years) and old-old (80+ years). METHODS: The Health and Anemia and Monzino 80-plus are two door-to-door, prospective population-based studies that included residents aged 65-plus years in Biella municipality and 80-plus years in Varese province, Italy. No exclusion criteria were used. RESULTS: Among 4,494 young-old and 1,842 old-old, mortality risk over 15/11 years was significantly higher in individuals with mild anemia compared with those without (young-old: fully-adjusted HR: 1.35, 95%CI, 1.15-1.58; old-old: fully-adjusted HR: 1.28, 95%CI, 1.14-1.44). Results were similar in the disease-free subpopulation (age, sex, education, smoking history, and alcohol consumption adjusted HR: 1.54, 95%CI, 1.02-2.34). Both age groups showed a dose-response relationship between anemia severity and mortality (P for trend <0.0001). Mortality risk was significantly associated with chronic disease and chronic kidney disease mild anemia in both age groups, and with vitamin B12/folate deficiency and unexplained mild anemia in young-old. In participants with two hemoglobin determinations, seven-year mortality risk was significantly higher in incident and persistent anemic cases compared to constant non-anemic individuals in both age groups. In participants without anemia at baseline also hemoglobin decline was significantly associated with an increased mortality risk over seven years in both young-old and old-old. Limited to the Monzino 80-plus study, the association remained significant also when the risk was further adjusted also for time-varying covariates and time-varying anemia status over time. CONCLUSIONS: Findings from these two large prospective population-based studies consistently suggest an independent, long-term impact of mild anemia on survival at older ages.

The role of diet on the risk of dementia in the oldest old: The Monzino 80-plus population-based study.

BACKGROUND & AIMS: Longevity also carries its dark side of age-related chronic diseases, dementia being one of the worst and the most prevalent. Since dementia lacks effective treatments, preventing or delaying it is highly desirable. Dietary habits and nutrition have been found to be important modifiable risk factors for many chronic diseases, but evidence on the role of diet on the risk of dementia is still limited, particularly among the very old. Aim of the present work is to study the association of the Mediterranean diet and its components with prevalent and incident dementia in the oldest-old. METHODS: We analyzed data from the Monzino 80-plus study, a population-based study in subjects 80 years or older in the Varese province, Italy. A validated food frequency questionnaire was used to collect information on 23 different foods consumed in the previous year. A Mediterranean diet score was calculated and its components were classified into tertiles. Multivariable models for dementia prevalence and incidence were adjusted for demographic and clinical characteristics. RESULTS: Information on nutrition was available for 1390 subjects in the cross-sectional study and 512 subjects in the longitudinal study, mean respective ages 93 and 92. Greater adherence to Mediterranean diet, greater consumption of eggs, fruits and vegetables, carbohydrates, and greater food intake were associated with a lower prevalence of dementia. Increasing number of portions per week and consumption of legumes significantly decreased the incidence of dementia during the 3.6 year mean follow-up: corresponding hazard ratios of highest vs. lowest tertiles (95% confidence intervals) were 0.66 (0.46-0.95) and 0.68 (0.47-0.97), respectively. CONCLUSION: Oldest-old eating less and having diets with less variety and nutrient density were more frequent among subjects with dementia. The longitudinal analysis confirmed oldest-old subjects who eat more portions, as well as those who have a higher intake of legumes, are at decreased risk of developing dementia even though reverse causality cannot be completely ruled out.

Can Anti-ß-amyloid Monoclonal Antibodies Work in Autosomal Dominant Alzheimer Disease?

The dominant theory of Alzheimer disease (AD) has been that amyloid-ß (Aß) accumulation in the brain is the initial cause of the degeneration leading to cognitive and functional deficits. Autosomal dominant Alzheimer disease (ADAD), in which pathologic mutations of the amyloid precursor protein (APP) or presenilins (PSENs) genes are known to cause abnormalities of Aß metabolism, should thus offer perhaps the best opportunity to test anti-Aß drugs. Two long-term preventive studies (Dominantly Inherited Alzheimer Network Trials Unit Adaptive Prevention Trial [DIAN-TU-APT] and Alzheimer Preventive Initiative-ADAD) were set up to evaluate the efficacy of monoclonal anti-Aß antibodies (solanezumab, gantenerumab, and crenezumab) in carriers of ADAD, but the results of the DIAN-TU-APT study have shown that neither solanezumab nor gantenerumab slowed cognitive decline in 144 subjects with ADAD followed for 4 years, despite one of the drugs (gantenerumab) significantly affected biomarkers relevant to their intended mechanism of action. Surprisingly, solanezumab significantly accelerated cognitive decline of both asymptomatic and symptomatic subjects. These failures further undermine the Aß hypothesis and could support the suggestion that ADAD is triggered by accumulation of other APP metabolites, rather than Aß.

How palliative care professionals deal with predicting life expectancy at the end of life: predictors and accuracy.

PURPOSE: To assess the accuracy of hospice staff in predicting survival of subjects admitted to hospice, exploring the factors considered most helpful by the hospice staff to accurately predict survival. METHODS: Five physicians and 11 nurses were asked to predict survival at admission of 827 patients. Actual and predicted survival times were divided into ≤ 1 week, 2-3 weeks, 4-8 weeks, and ≥ 2 months and the accuracy of the estimates was calculated. The staff members were each asked to score 17 clinical variables that guided them in predicting survival and we analyzed how these variables impacted the accuracy. RESULTS: Physicians' and nurses' accuracy of survival of the patients was 46% and 40% respectively. Survival was underestimated in 20% and 12% and overestimated in 34% and 48% of subjects. Both physicians and nurses considered metastases, comorbidities, dyspnea, disability, tumor site, neurological symptoms, and confusion very important in predicting patients' survival with nurses assigning more importance to intestinal symptoms and pain too. All these factors, with the addition of cough and/or bronchial secretions, were associated with physicians' greater accuracy. In the multivariable models, intestinal symptoms and confusion continued to be associated with greater predictive accuracy. No factors appreciably raised nurses' accuracy. CONCLUSIONS: Some clinical symptoms rated as relevant by the hospice staff could be important for predicting survival. However, only intestinal symptoms and confusion significantly improved the accuracy of physicians' predictions, despite the high prevalence of overestimated survival.

The SPID-GBA study: Sex distribution, Penetrance, Incidence, and Dementia in GBA-PD.

OBJECTIVE: To provide a variant-specific estimate of incidence, penetrance, sex distribution, and association with dementia of the 4 most common Parkinson disease (PD)-associated GBA variants, we analyzed a large cohort of 4,923 Italian unrelated patients with primary degenerative parkinsonism (including 3,832 PD) enrolled in a single tertiary care center and 7,757 ethnically matched controls. METHODS: The p.E326K, p.T369M, p.N370S, and p.L444P variants were screened using an allele-specific multiplexed PCR approach. All statistical procedures were performed using R or Plink v1.07. RESULTS: Among the 4 analyzed variants, the p.L444P confirmed to be the most strongly associated with disease risk for PD, PD dementia (PDD), and dementia with Lewy bodies (DLB) (odds ratio [OR] for PD 15.63, 95% confidence interval [CI] = 8.04-30.37, p = 4.97*10-16; OR for PDD 29.57, 95% CI = 14.07-62.13, p = 3.86*10-19; OR for DLB 102.7, 95% CI = 31.38-336.1, p = 1.91*10-14). However, an unexpectedly high risk for dementia was conferred by p.E326K (OR for PDD 4.80, 95% CI = 2.87-8.02, p = 2.12*10-9; OR for DLB 12.24, 95% CI = 4.95-30.24, p = 5.71*10-8), which, on the basis of the impact on glucocerebrosidase activity, would be expected to be mild. The 1.5-2:1 male sex bias described in sporadic PD was lost in p.T369M carriers. We also showed that PD penetrance for p.L444P could reach the 15% at age 75 years. CONCLUSIONS: We report a large monocentric study on GBA-PD assessing mutation-specific data on the sex distribution, penetrance, incidence, and association with dementia of the 4 most frequent deleterious variants in GBA.

Relation between anticholinergic burden and cognitive impairment: Results from the Monzino 80-plus population-based study.

PURPOSE: We examined data collected in the Monzino 80-plus study to assess the relations between cognitive performance and ACB scores according to the hypothesis that a higher anticholinergic burden is associated with reduced cognitive performance. METHODS: The Monzino 80-plus is an ongoing, prospective, door-to-door population-based study started in 2002 among all residents 80 years or older in eight municipalities of Varese province, Italy. To establish the relation between cognitive impairment and the anticholinergic drug burden we recorded the ACB score for each patient at baseline. The relations between ACB score and dementia or MMSE scores were also examined after exclusion of patients taking any antipsychotic. RESULTS: A sample of 2140 elderly people was eligible for analysis. A significant dose-effect relationship was observed between total ACB score and diagnosis of dementia in univariate and multivariate models. Patients in ACB class ≥4 had about 4.5 times the risk of diagnosis of dementia. A relation was also found between higher ACB scores and lower MMSE scores; patients who scored 4 or more had a mean of 6.4 points lower than those not taking anticholinergic drugs. The dose-effect relationship between ACB score and diagnosis of dementia was not maintained after exclusion of patients using antipsychotics, while the association between higher ACB scores and lower MMSE scores was still present, with patients in ACB class ≥4 having a mean score about 4.4 lower. CONCLUSIONS: There are clear relations between anticholinergic load and reduced cognitive performance, while the association with dementia remains uncertain. For primary care and geriatric clinicians, an ACB score ≥ 4 can be considered the cut-off to identify high-risk populations who may benefit from the evaluation of anticholinergic burden with the ACB scale.

The Italian Version of the Test Your Memory (TYM-I): A Tool to Detect Mild Cognitive Impairment in the Clinical Setting.

The Test Your Memory (TYM) is a brief self-administered, cognitive screening test, currently used in several settings. It requires minimal administrator supervision and the computation of the final test score takes approximately 2 min. We assessed the discrimination ability of the Italian version of the TYM (TYM-I) in detecting Mild Cognitive Impairment (MCI) in clinical setting. TYM-I was administered to 94 MCI patients and 134 healthy controls. The clinical diagnosis of MCI was considered as the gold standard. An extended formal neuropsychological test battery was used to define MCI subtypes. Receiver Operating Characteristic (ROC) analyses were conducted to find the optimal cut-off and measure discrimination ability of TYM-I in detecting MCI. TYM-I had a similar area under the curve (AUC = 0.85) point estimate as Mini Mental State Examination (MMSE) (AUC = 0.83). A TYM-I score lower or equal to 36 was found to be optimal cut off to detect MCI. The TYM-I showed the highest discrimination ability among individuals aged more than 70 and high educational level (AUC = 0.89). The amnestic MCI subtype patients, compared to non-amnestic MCI patients, had worse performance in recall, orientation and visuospatial abilities TYM-I subscores. The TYM-I is a valid screening test in detecting cognitive dysfunction, easily carried out in clinical practice. The TYM-I subscores may allow to identify amnestic and non-amnestic MCI subtypes.

Association of renal function with cognition, functional ability and mood in the oldest-old: The 'Health and Anemia study'.

AIM: In this study, the relationship between kidney function, cognitive performance, functional abilities and mood was investigated in a community-dwelling Italian oldest-old population. METHODS: Serum creatinine was used to calculate estimated glomerular filtration rate (eGFR) using the Modification of Diet in Renal Disease formula, for 415 oldest-old without dementia participating in the 'Health and Anemia' study, a prospective, observational cohort study. The cross-sectional associations of kidney function with cognitive performance on several neuropsychological tests, basic and instrumental functional abilities and mood were analyzed using univariate and multivariable linear regression models. RESULTS: Cognitive performance and functional ability significantly worsened with decreasing kidney function. After adjusting for age, sex, education, comorbidity index of the Cumulative Illness Rating Scale (CIRS), body mass index, bone fracture and serum ferritin levels the associations of eGFR categories with basic and instrumental functional abilities continued to be statistically significant whereas that with global cognitive functions did not. No significant independent association was found between renal function and mood. CONCLUSIONS: Oldest-old with reduced kidney function showed greater basic and instrumental functional disabilities, while cognitive function, although decreased with decreasing eGFR, was no longer significantly associated with eGFR categories after adjusting for confounders.

Incidence of dementia in the oldest-old and its relationship with age: The Monzino 80-plus population-based study.

INTRODUCTION: Relationship between age and dementia at extreme old ages is still an open question, yet population-based studies in this high-risk age segment are rare. METHODS: The Monzino 80-plus is a population-based study among residents 80 years and older in the Varese province, Italy. Of 1371 eligible individuals, 1294 (94.4%), of whom 64 are centenarians, were included in the incidence study. RESULTS: Since 2002, 584 new cases of all-cause dementia were identified over 15 years. The overall incidence rate was 7.9 per 100 person-years. Dementia risk rose with age (IRR: 1.06), with the cubic model providing the best fit (R2  = 0.91-0.96). Cumulative incidences of dementia unadjusted and adjusted for competing mortality risk progressively diverged with age. CONCLUSION: Dementia incidence also keeps rising in nonagenarians and centenarians. Slowing down in growing risk of developing dementia with age is mainly attributable to increasing competing risk of death and resulting selective survival of individuals at lower risk of dementia.

Nilvadipine in mild to moderate Alzheimer disease: A randomised controlled trial.

BACKGROUND: This study reports the findings of the first large-scale Phase III investigator-driven clinical trial to slow the rate of cognitive decline in Alzheimer disease with a dihydropyridine (DHP) calcium channel blocker, nilvadipine. Nilvadipine, licensed to treat hypertension, reduces amyloid production, increases regional cerebral blood flow, and has demonstrated anti-inflammatory and anti-tau activity in preclinical studies, properties that could have disease-modifying effects for Alzheimer disease. We aimed to determine if nilvadipine was effective in slowing cognitive decline in subjects with mild to moderate Alzheimer disease. METHODS AND FINDINGS: NILVAD was an 18-month, randomised, placebo-controlled, double-blind trial that randomised participants between 15 May 2013 and 13 April 2015. The study was conducted at 23 academic centres in nine European countries. Of 577 participants screened, 511 were eligible and were randomised (258 to placebo, 253 to nilvadipine). Participants took a trial treatment capsule once a day after breakfast for 78 weeks. Participants were aged >50 years, meeting National Institute of Neurological and Communicative Disorders and Stroke/Alzheimer's disease Criteria (NINCDS-ADRDA) for diagnosis of probable Alzheimer disease, with a Standardised Mini-Mental State Examination (SMMSE) score of ≥12 and <27. Participants were randomly assigned to 8 mg sustained-release nilvadipine or matched placebo. The a priori defined primary outcome was progression on the Alzheimer's Disease Assessment Scale Cognitive Subscale-12 (ADAS-Cog 12) in the modified intention-to-treat (mITT) population (n = 498), with the Clinical Dementia Rating Scale sum of boxes (CDR-sb) as a gated co-primary outcome, eligible to be promoted to primary end point conditional on a significant effect on the ADAS-Cog 12. The analysis set had a mean age of 73 years and was 62% female. Baseline demographic and Alzheimer disease-specific characteristics were similar between treatment groups, with reported mean of 1.7 years since diagnosis and mean SMMSE of 20.4. The prespecified primary analyses failed to show any treatment benefit for nilvadipine on the co-primary outcome (p = 0.465). Decline from baseline in ADAS-Cog 12 on placebo was 0.79 (95% CI, -0.07-1.64) at 13 weeks, 6.41 (5.33-7.49) at 52 weeks, and 9.63 (8.33-10.93) at 78 weeks and on nilvadipine was 0.88 (0.02-1.74) at 13 weeks, 5.75 (4.66-6.85) at 52 weeks, and 9.41 (8.09-10.73) at 78 weeks. Exploratory analyses of the planned secondary outcomes showed no substantial effects, including on the CDR-sb or the Disability Assessment for Dementia. Nilvadipine appeared to be safe and well tolerated. Mortality was similar between groups (3 on nilvadipine, 4 on placebo); higher counts of adverse events (AEs) on nilvadipine (1,129 versus 1,030), and serious adverse events (SAEs; 146 versus 101), were observed. There were 14 withdrawals because of AEs. Major limitations of this study were that subjects had established dementia and the likelihood that non-Alzheimer subjects were included because of the lack of biomarker confirmation of the presence of brain amyloid. CONCLUSIONS: The results do not suggest benefit of nilvadipine as a treatment in a population spanning mild to moderate Alzheimer disease. TRIAL REGISTRATION: Clinicaltrials.gov NCT02017340, EudraCT number 2012-002764-27.

Relationship between atrial fibrillation and cognitive decline in individuals aged 80 and older.

BACKGROUND: Atrial fibrillation (AF) and dementia are largely prevalent and incident in progressively older subjects, suggesting a link between the two conditions. While in the general population there are several findings supporting a causal relationship between AF and dementia, it is unclear whether or not this association is still present in individuals aged 80 and older. RESULTS: So far, the few studies that analysed this issue did not provide enough evidence supporting the causative role of AF in increasing the risk of cognitive decline or dementia in patients aged 80 and older. Conversely, a relevant role of optimal anticoagulation control in determining a significant reduction in the risk of cognitive decline is suggested, in AF subjects aged 80years or older. CONCLUSIONS: Further data, coming from population-based studies specifically investigating very old individuals and based upon large samples and comprehensive cognitive assessments, are needed to fully elucidate the relationship between AF and dementia in very old individuals.

Prognostic value of degree and types of anaemia on clinical outcomes for hospitalised older patients.

STUDY OBJECTIVE: This study investigated in a large sample of in-patients the impact of mild-moderate-severe anaemia on clinical outcomes such as in-hospital mortality, re-admission, and death within three months after discharge. METHODS: A prospective multicentre observational study, involving older people admitted to 87 internal medicine and geriatric wards, was done in Italy between 2010 and 2012. The main clinical/laboratory data were obtained on admission and discharge. Based on haemoglobin (Hb), subjects were classified in three groups: group 1 with normal Hb, (reference group), group 2 with mildly reduced Hb (10.0-11.9g/dL in women; 10.0-12.9g/dL in men) and group 3 with moderately-severely reduced Hb (<10g/dL in women and men). RESULTS: Patients (2678; mean age 79.2±7.4y) with anaemia (54.7%) were older, with greater functional impairment and more comorbidity. Multivariable analysis showed that mild but not moderate-severe anaemia was associated with a higher risk of hospital re-admission within three months (group 2: OR=1.62; 95%CI 1.21-2.17). Anaemia failed to predict in-hospital mortality, while a higher risk of dying within three months was associated with the degree of Hb reduction on admission (group 2: OR=1.82;95%CI 1.25-2.67; group 3: OR=2.78;95%CI 1.82-4.26) and discharge (group 2: OR=2.37;95%CI 1.48-3.93; group 3: OR=3.70;95%CI 2.14-6.52). Normocytic and macrocytic, but not microcytic anaemia, were associated with adverse clinical outcomes. CONCLUSIONS: Mild anaemia predicted hospital re-admission of older in-patients, while three-month mortality risk increased proportionally with anaemia severity. Type and severity of anaemia affected hospital re-admission and mortality, the worst prognosis being associated with normocytic and macrocytic anaemia.

Nutrition for the ageing brain: Towards evidence for an optimal diet.

As people age they become increasingly susceptible to chronic and extremely debilitating brain diseases. The precise cause of the neuronal degeneration underlying these disorders, and indeed normal brain ageing remains however elusive. Considering the limits of existing preventive methods, there is a desire to develop effective and safe strategies. Growing preclinical and clinical research in healthy individuals or at the early stage of cognitive decline has demonstrated the beneficial impact of nutrition on cognitive functions. The present review is the most recent in a series produced by the Nutrition and Mental Performance Task Force under the auspice of the International Life Sciences Institute Europe (ILSI Europe). The latest scientific advances specific to how dietary nutrients and non-nutrient may affect cognitive ageing are presented. Furthermore, several key points related to mechanisms contributing to brain ageing, pathological conditions affecting brain function, and brain biomarkers are also discussed. Overall, findings are inconsistent and fragmented and more research is warranted to determine the underlying mechanisms and to establish dose-response relationships for optimal brain maintenance in different population subgroups. Such approaches are likely to provide the necessary evidence to develop research portfolios that will inform about new dietary recommendations on how to prevent cognitive decline.

Older patients are still under-represented in clinical trials of Alzheimer's disease.

BACKGROUND: The age gap between participants in trials and patients who could benefit from the drugs studied has been widely documented across different clinical areas. Patients with dementia included in clinical research are systematically younger than those in the general population. We examined the age gap between participants in recent clinical trials testing interventions for Alzheimer's disease and epidemiological data. METHODS: We systematically searched literature databases (MedLine, EMBASE, the Cochrane Library) and ClinicalTrials.gov from 2000 to July 2015 to retrieve clinical trials testing pharmacologic treatments for Alzheimer's disease, other than cholinesterase inhibitors and memantine. We included ongoing and completed phase II/III randomized clinical trials, irrespective of their publication status. From each study reporting the participants' ages, we extracted size of sample, mean age, and standard deviation, and estimated the proportions of participants in different age classes. The number of patients with Alzheimer's disease by age class in the USA population was used for comparison. RESULTS: We included 165 clinical trials testing almost 100 different compounds, which enrolled or planned to enroll about 74,300 participants. Seventy-nine of these trials, accounting for about 26,800 participants, reported the age of the participants. The weighted mean age was 73.6 years (standard deviation, 8.2). People younger than 80 years were highly represented in clinical trials (78 %), despite the fact that those aged 80 and older form the majority (72 %) of patients with Alzheimer's disease. Only 8 % of clinical trial participants were 85 years or older. CONCLUSIONS: Patients enrolled in clinical trials on Alzheimer's disease are far from being representative of actual distribution of the patients in the general population. Clinical research should not be designed and conducted overlooking the fact that the majority of individuals with Alzheimer's disease are likely to be 80 or older.