Twenty-seven-year time trends in dementia incidence in Europe and the United States: The Alzheimer Cohorts Consortium

OBJECTIVE

To determine changes in the incidence of dementia between 1988 and 2015.

METHODS

This analysis was performed in aggregated data from individuals >65 years of age in 7 population-based cohort studies in the United States and Europe from the Alzheimer Cohort Consortium. First, we calculated age- and sex-specific incidence rates for all-cause dementia, and then defined nonoverlapping 5-year epochs within each study to determine trends in incidence. Estimates of change per 10-year interval were pooled and results are presented combined and stratified by sex.

RESULTS

Of 49,202 individuals, 4,253 (8.6%) developed dementia. The incidence rate of dementia increased with age, similarly for women and men, ranging from about 4 per 1,000 person-years in individuals aged 65-69 years to 65 per 1,000 person-years for those aged 85-89 years. The incidence rate of dementia declined by 13% per calendar decade (95% confidence interval [CI], 7%-19%), consistently across studies, and somewhat more pronouncedly in men than in women (24% [95% CI 14%-32%] vs 8% [0%-15%]).

CONCLUSION

The incidence rate of dementia in Europe and North America has declined by 13% per decade over the past 25 years, consistently across studies. Incidence is similar for men and women, although declines were somewhat more profound in men. These observations call for sustained efforts to finding the causes for this decline, as well as determining their validity in geographically and ethnically diverse populations.

Plasma tau, neurofilament light chain and amyloid-β levels and risk of dementia; a population-based cohort study

CSF biomarkers, including total-tau, neurofilament light chain (NfL) and amyloid-β, are increasingly being used to define and stage Alzheimer’s disease. These biomarkers can be measured more quickly and less invasively in plasma and may provide important information for early diagnosis of Alzheimer’s disease. We used stored plasma samples and clinical data obtained from 4444 non-demented participants in the Rotterdam study at baseline (between 2002 and 2005) and during follow-up until January 2016. Plasma concentrations of total-tau, NfL, amyloid-β₄₀ and amyloid-β₄₂ were measured using the Simoa NF-light^® and N3PA assays. Associations between biomarker plasma levels and incident all-cause and Alzheimer’s disease dementia during follow-up were assessed using Cox proportional-hazard regression models adjusted for age, sex, education, cardiovascular risk factors and APOE ε4 status. Moreover, biomarker plasma levels and rates of change over time of participants who developed Alzheimer’s disease dementia during follow-up were compared with age and sex-matched dementia-free control subjects. During up to 14 years follow-up, 549 participants developed dementia, including 374 cases with Alzheimer’s disease dementia. A log₂ higher baseline amyloid-β₄₂ plasma level was associated with a lower risk of developing all-cause or Alzheimer’s disease dementia, adjusted hazard ratio (HR) 0.61 [95% confidence interval (CI), 0.47–0.78; P < 0.0001] and 0.59 (95% CI, 0.43–0.79; P = 0.0006), respectively. Conversely, a log₂ higher baseline plasma NfL level was associated with a higher risk of all-cause dementia [adjusted HR 1.59 (95% CI, 1.38–1.83); P < 0.0001] or Alzheimer’s disease [adjusted HR 1.50 (95% CI, 1.26–1.78); P < 0.0001]. Combining the lowest quartile group of amyloid-β₄₂ with the highest of NfL resulted in a stronger association with all-cause dementia [adjusted HR 9.5 (95% CI, 2.3–40.4); P < 0.002] and with Alzheimer’s disease [adjusted HR 15.7 (95% CI, 2.1–117.4); P < 0.0001], compared to the highest quartile group of amyloid-β₄₂ and lowest of NfL. Total-tau and amyloid-β₄₀ levels were not associated with all-cause or Alzheimer’s disease dementia risk. Trajectory analyses of biomarkers revealed that mean NfL plasma levels increased 3.4 times faster in participants who developed Alzheimer’s disease compared to those who remained dementia-free (P < 0.0001), plasma values for cases diverged from controls 9.6 years before Alzheimer’s disease diagnosis. Amyloid-β₄₂ levels began to decrease in Alzheimer’s disease cases a few years before diagnosis, although the decline did not reach significance compared to dementia-free participants. In conclusion, our study shows that low amyloid-β₄₂ and high NfL plasma levels are each independently and in combination strongly associated with risk of all-cause and Alzheimer’s disease dementia. These data indicate that plasma NfL and amyloid-β₄₂ levels can be used to assess the risk of developing dementia in a non-demented population. Plasma NfL levels, although not specific, may also be useful in monitoring progression of Alzheimer’s disease dementia.

Tamm plasmons in metal/nanoporous GaN distributed Bragg reflector cavities for active and passive optoelectronics

We theoretically and experimentally investigate Tamm plasmon (TP) modes in a metal/semiconductor distributed Bragg reflector (DBR) interface. A thin Ag (silver) layer with a thickness (55 nm from simulation) that is optimized to guarantee a low reflectivity at the resonance was deposited on nanoporous GaN DBRs fabricated using electrochemical (EC) etching on freestanding semipolar (2021¯) GaN substrates. The reflectivity spectra of the DBRs are compared before and after the Ag deposition and with that of a blanket Ag layer deposited on GaN. The experimental results indicate the presence of a TP mode at ∼ 454 nm on the structure after the Ag deposition, which is also supported by theoretical calculations using a transfer-matrix algorithm. The results from mode dispersion with energy-momentum reflectance spectroscopy measurements also support the presence of a TP mode at the metal-nanoporous GaN DBR interface. An active medium can also be accommodated within the mode for optoelectronics and photonics. Moreover, the simulation results predict a sensitivity of the TP mode wavelength to the ambient (∼ 4-7 nm shift when changing the ambient within the pores from air with n = 1 to isopropanol n = 1.3), suggesting an application of the nanoporous GaN-based TP structure for optical sensing.

P2531Impact of age on clinical outcomes after PCI in patients with ACS and stable CAD treated with 23-month ticagrelor monotherapy following 1-month DAPT in the randomized GLOBAL LEADERS study

Background

The efficacy and safety of ticagrelor monotherapy in elderly patients undergoing percutaneous coronary intervention (PCI) for acute coronary syndromes (ACS) or stable coronary artery disease (CAD) has not been evaluated.

Purpose

To evaluate the efficacy and safety of ticagrelor monotherapy following 1-month dual antiplatelet therapy (DAPT) after PCI in relation to age and clinical presentation in the GLOBAL LEADERS study cohort.

Methods

This is a subanalysis of the randomized multicentre GLOBAL LEADERS study, comparing the experimental strategy of 23-month ticagrelor monotherapy after 1 month of ticagrelor and aspirin with the reference strategy of 12-month DAPT followed by 12-month aspirin monotherapy in 15991 patients undergoing PCI. Patients were categorized into elderly and very elderly according to a pre-specified cut-off of 75 years and a post-hoc defined cut-off of 80 years. Impact of age and clinical presentation (ACS versus stable CAD) on clinical outcome at 2 years was evaluated. The primary endpoint was a composite of all-cause mortality or nonfatal, centrally adjudicated, new Q-wave myocardial infarction.

Results

In the overall elderly (>75 years) population (n=2565), primary endpoint occurred in 7.2% of patients in the experimental group and in 9.4% of patients in the reference group (p=0.041) at 2 years (p int =0.23). Elderly patients in the experimental group had a lower rate of definite stent thrombosis (ST) (0.2% vs. 0.9%, p=0.043, p int=0.03), definite or probable ST (0.4 vs. 1.3%, p=0.015, p int=0.01) and a numerically higher rates of BARC 3 or 5 type bleeding (5.0% vs. 3.9%, p=0.192, p int=0.06), when compared to the reference arm.

Among elderly patients presenting with ACS both treatment groups did not differ in the rates of primary endpoint (9.1% vs. 10.8%, p=0.367) and BARC 3 or 5 type bleeding (4.7% vs. 5.7%, p=0.458), whereas among elderly patients with stable CAD the experimental strategy was associated with numerically lower rates of the primary endpoint (5.7% vs. 8.4%, p=0.046) (p int =0.42) and a higher rate of BARC 3 or 5 type bleedings (5.3% vs. 2.6%, p=0.012) (p int =0.02) at 2 years.

Exploratory analyses among very elderly (≥80 years) patients (n=1169) indicated no significant differences between treatment groups in the rates of the primary endpoint (10.2% vs. 11.7% p=0.411, p int=0.940) and BARC 3 or 5 type bleeding (6.0% vs. 5.3%, p=0.630, p int=0.514) at 2 years.

Conclusions

The efficacy and safety of the experimental treatment strategy of 23-month ticagrelor monotherapy after 1-month DAPT following PCI was not identified as age-dependent. Among elderly patients the anti-ischemic benefit was derived at the expense of increased rate of BARC 3 or 5 type bleeding in stable CAD subgroup, but not in ACS subgroup.

Acknowledgement/Funding

European Clinical Research Institute, which received unrestricted grants from Biosensors International, AstraZeneca, and the Medicines Company.

Heterogeneity in transmission parameters of hookworm infection within the baseline data from the TUMIKIA study in Kenya

Background

As many countries with endemic soil-transmitted helminth (STH) burdens achieve high coverage levels of mass drug administration (MDA) to treat school-aged and pre-school-aged children, understanding the detailed effects of MDA on the epidemiology of STH infections is desirable in formulating future policies for morbidity and/or transmission control. Prevalence and mean intensity of infection are characterized by heterogeneity across a region, leading to uncertainty in the impact of MDA strategies. In this paper, we analyze this heterogeneity in terms of factors that govern the transmission dynamics of the parasite in the host population.

Results

Using data from the TUMIKIA study in Kenya (cluster STH prevalence range at baseline: 0–63%), we estimated these parameters and their variability across 120 population clusters in the study region, using a simple parasite transmission model and Gibbs-sampling Monte Carlo Markov chain techniques. We observed great heterogeneity in R₀ values, with estimates ranging from 1.23 to 3.27, while k-values (which vary inversely with the degree of parasite aggregation within the human host population) range from 0.007 to 0.29 in a positive association with increasing prevalence. The main finding of this study is the increasing trend for greater parasite aggregation as prevalence declines to low levels, reflected in the low values of the negative binomial parameter k in clusters with low hookworm prevalence. Localized climatic and socioeconomic factors are investigated as potential drivers of these observed epidemiological patterns.

Conclusions

Our results show that lower prevalence is associated with higher degrees of aggregation and hence prevalence alone is not a good indicator of transmission intensity. As a consequence, approaches to MDA and monitoring and evaluation of community infection status may need to be adapted as transmission elimination is aimed for by targeted treatment approaches.

Female cognitive performance and mass are correlated with different aspects of mate choice in the zebra finch (Taeniopygia guttata)

A female's cognitive ability may influence her mate preferences through various mechanisms. These mechanisms include the direct effect of cognitive ability on the information-processing skills used during mate choice, and the indirect effect of cognitive ability on quality when females mate assortatively. Here, we examined whether the ability to learn a novel foraging task, a cognitive skill which has been associated with reproductive success in other capacities, was correlated with song preferences in female zebra finches (Taeniopygia guttata). Female preferences were measured in an operant testing chamber where hops on a perch triggered song playback. Females were given the choice of (1) conspecific vs. heterospecific song and (2) high-quality male vs. low-quality male conspecific song. We found that female performance on the novel foraging task was positively correlated with preference for conspecific song, but not with preference for high-quality male song. Instead, female mass was positively correlated with preference for high-quality male song, potentially signifying that female mass is a stronger predictor of female quality in assortative mating than female cognitive performance. Female mass and cognitive performance were unrelated. Our results suggest that the particular traits of a female that affect conspecific preference do not necessarily affect preference for high-quality males.

A comparison of two models of follow-up care for adult survivors of childhood cancer

PURPOSE

Few studies have compared follow-up-care models for adult survivors of childhood cancer (ASCCs), though choice of model could impact medical test adherence, and health-related quality of life (QOL). This study compared two follow-up-care models, cancer-center-based versus community-based, for ASCCs in Alberta, Canada, to determine which model would demonstrate greater ASCC adherence to guideline-recommended medical screening tests for late effects, QOL, physical symptoms, and adherence to yearly follow-up.

METHODS

ASCC discharged to a community model (over 15 years) and those with comparable birth years (1973-1993) currently followed in a cancer center model were recruited via direct contact or multimedia campaign. Chart review identified chemotherapeutic and radiation exposures, and required medical late effect screening tests. ASCCs also completed questionnaires assessing QOL, physical symptoms, and follow-up behavior.

RESULTS

One hundred fifty-six survivors participated (community (n = 86); cancer center (n = 70)). Primary analysis indicated that cancer center ASCCs guideline-recommended total test adherence percentage (Mdn = 85.4%) was significantly higher than the community model (Mdn = 29.2%, U = 3996.50, p < 0.0001). There was no significant difference in QOL for cancer center ASCCs (M = 83.85, SD = 20.55 versus M = 77.50, SD = 23.94; t (154) = 1.77, p = 0.078) compared to community-based ASCCs. Cancer center-based ASCCs endorsed from 0.4-7.1% fewer physical symptom clusters, and higher adherence to follow-up behavior in comparisons using effect sizes without p values.

CONCLUSION

This study highlights the cancer center model's superiority for adherence to exposure-based medical late effect screening guidelines, cancer-specific follow-up behaviors, and the reporting of fewer physical complaints in ASCCs.

IMPLICATIONS FOR CANCER SURVIVORS

ASCCs followed in a cancer center model likely benefit from earlier late-effects detection and opportunities for early intervention.

Pathogenesis and prevention of risk of cardiovascular events in patients with pneumococcal community-acquired pneumonia

It is now well recognized that cardiovascular events (CVE) occur quite commonly, both in the acute phase and in the long-term, in patients with community-acquired pneumonia (CAP). CVE have been noted in up to 30% of patients hospitalized with all-cause CAP. One systematic review and meta-analysis of hospitalized patients with all-cause CAP noted that the incidence rates for overall cardiac events were 17.7%, for incident heart failure were 14.1%, for acute coronary syndromes were 5.3% and for incident cardiac arrhythmias were 4.7%. In the case of pneumococcal CAP, almost 20% of patients studied had one or more of these cardiac events. Recent research has provided insights into the pathogenesis of the acute cardiac events occurring in pneumococcal infections. With respect to the former, key involvements of the major pneumococcal protein virulence factor, pneumolysin, are now well documented, whilst systemic platelet-driven neutrophil activation may also contribute. However, events involved in the pathogenesis of the long-term cardiovascular sequelae remain largely unexplored. Emerging evidence suggests that persistent antigenaemia may predispose to the development of a systemic pro-inflammatory/prothrombotic phenotype underpinning the risk of future cardiovascular events. The current manuscript briefly reviews the occurrence of cardiovascular events in patients with all-cause CAP, as well as in pneumococcal and influenza infections. It highlights the close interaction between influenza and pneumococcal pneumonia. It also includes a brief discussion of mechanisms of the acute cardiac events in CAP. However, the primary focus is on the prevalence, pathogenesis and prevention of the longer-term cardiac sequelae of severe pneumococcal disease, particularly in the context of persistent antigenaemia and associated inflammation.

Abstract PD9-05: The importance of the metastatic biopsy: Clinical and translational relevance in a real world series of patients with metastatic breast cancer

Background

Metastatic breast cancer (MBC) is a heterogeneous disease, whose clinical course and prognosis may be unpredictable, creating significant uncertainty for patients and their families. Heterogeneity is breast cancer subtypes is now well recognized as a potential reason for treatment resistance. Sampling metastatic sites at the point of diagnosis or upon progression, when safe, is recommended to better guide therapy.

Purpose

This study evaluated patients currently undergoing treatment for MBC in the clinic to determine the clinical and translational significance of a metastatic sample.

Methods

Patients currently undergoing treatment for MBC at the Olivia Newton John Centre were identified. Data was collected on patient demographics, clinicopathological information, treatment and duration of response. Translational research tissue was collected, with consent, for DNA and RNA analysis.

Results

Between January 2017 and May 2018 111 patients were identified. The mean age of MBC diagnosis was 60 years (range 30-87), with a mean follow up time of 2.4 years (range 0.8-16). Fifteen patients died during the study period. Sixty-seven (60%) patients were initially treated for early breast cancer (EBC), with a median disease free interval (DFI) 4.7 years. Half (51%) these patients relapsed after five years.

At MBC diagnosis, multiple sites of disease were identified including bone, visceral, brain, nodal and skin/chest wall disease. Bone only disease was common (25%), whereas brain disease was rare overall (9%). Metastatic tissue was collected in 67 (60%) patients, where up to four different sites were biopsied. The most commonly biopsied site was bone (n=21), followed by soft tissue (n=20), chest wall/skin disease (n=12), liver (n=9), lung (n=8) and brain (n=8). Serous disease was collected in 16 patients, including pleural, pericardial, ascitic and cerebrospinal fluid.

Based on the EBC subtype (n=67), 70% had luminal disease, 19% had Her2 positive disease and 7% had TNBC. However, based on a metastatic biopsy (n=67), only 61% of patients had luminal disease, 21% had HER2 positive, and 18% had TNBC. Paired EBC and MBC samples were available in 48 patients, with significant change in breast cancer subtype demonstrated in 12 of these patients (25%). The most common change was a loss in ER staining, which included 6 patients from ER positive, HER2 negative to TNBC and three patients who became ER negative but remained HER2 positive. Molecular profiling was performed thus far on 8 samples at the single cell and bulk level. These results highlight a large level of inter- and intra-tumoral heterogeneity, and may result in a better understanding of the molecular pathways specifically deregulated in patients at the point of progression.

Conclusion

In this single institution series of patients with MBC, over half of the cohort underwent at least one metastatic biopsy. Strikingly, a quarter of patients demonstrated a change in their breast cancer subtype, which directly guided subsequent therapy. Metastatic tissue can provide vital information to inform treatment decisions, which may be guided by translational laboratories having access to fresh tissue at the point of metastatic diagnosis or disease progression.

Citation Format: Yeo B, Molinaro T, Merino D, Berthelet J, Pouliot N, Fang C, Bell C, Anderson R. The importance of the metastatic biopsy: Clinical and translational relevance in a real world series of patients with metastatic breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr PD9-05.