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2.
Circ Res ; 125(8): 773-782, 2019 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-31476962

RESUMO

Rationale: Proinflammatory cytokines have been identified as potential targets for lowering vascular risk. Experimental evidence and Mendelian randomization suggest a role of MCP-1 (monocyte chemoattractant protein-1) in atherosclerosis and stroke. However, data from large-scale observational studies are lacking. Objective: To determine whether circulating levels of MCP-1 are associated with risk of incident stroke in the general population. Methods and Results: We used previously unpublished data on 17 180 stroke-free individuals (mean age, 56.7±8.1 years; 48.8% men) from 6 population-based prospective cohort studies and explored associations between baseline circulating MCP-1 levels and risk of any stroke, ischemic stroke, and hemorrhagic stroke during a mean follow-up interval of 16.3 years (280 522 person-years at risk; 1435 incident stroke events). We applied Cox proportional-hazards models and pooled hazard ratios (HRs) using random-effects meta-analyses. After adjustments for age, sex, race, and vascular risk factors, higher MCP-1 levels were associated with increased risk of any stroke (HR per 1-SD increment in ln-transformed MCP-1, 1.07; 95% CI, 1.01-1.14). Focusing on stroke subtypes, we found a significant association between baseline MCP-1 levels and higher risk of ischemic stroke (HR, 1.11 [1.02-1.21]) but not hemorrhagic stroke (HR, 1.02 [0.82-1.29]). The results followed a dose-response pattern with a higher risk of ischemic stroke among individuals in the upper quartiles of MCP-1 levels as compared with the first quartile (HRs, second quartile: 1.19 [1.00-1.42]; third quartile: 1.35 [1.14-1.59]; fourth quartile: 1.38 [1.07-1.77]). There was no indication for heterogeneity across studies, and in a subsample of 4 studies (12 516 individuals), the risk estimates were stable after additional adjustments for circulating levels of IL (interleukin)-6 and high-sensitivity CRP (C-reactive protein). Conclusions: Higher circulating levels of MCP-1 are associated with increased long-term risk of stroke. Our findings along with genetic and experimental evidence suggest that MCP-1 signaling might represent a therapeutic target to lower stroke risk.Visual Overview: An online visual overview is available for this article.

3.
PLoS One ; 14(8): e0219261, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31393881

RESUMO

Emerging evidence suggests microRNAs (miRNAs) may play an important role in explaining variation in stroke risk and recovery in humans, yet there are still few longitudinal studies examining the association between whole blood miRNAs and stroke. Accounting for multiple testing and adjusting for potentially confounding technical and clinical variables, here we show that whole blood miR-574-3p expression was significantly lower in participants with chronic stroke compared to non-cases. To explore the functional relevance of our findings, we analyzed miRNA-mRNA whole blood co-expression, pathway enrichment, and brain tissue gene expression. Results suggest miR-574-3p is involved in neurometabolic and chronic neuronal injury response pathways, including brain gene expression of DBNDD2 and ELOVL1. These results suggest miR-574-3p plays a role in regulating chronic brain and systemic cellular response to stroke and thus may implicate miR-574-3p as a partial mediator of long-term stroke outcomes.

4.
Ann Clin Transl Neurol ; 6(9): 1659-1670, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31373442

RESUMO

OBJECTIVE: To determine the association between plasma insulin-like growth factor binding protein 2 (IGFBP-2) and cognitive outcomes. METHODS: We measured plasma IGFBP-2 levels in 1596 (53% women, mean age 68.7 [SD 5.7] years) dementia-free Framingham Offspring cohort participants between 1998 and 2001. Multivariable Cox proportional hazards models related plasma IGFBP-2 to subsequent risk of incident dementia and Alzheimer's disease. MRI brain measures and cognitive performance were included as secondary outcomes. RESULTS: During a median follow-up of 11.8 (Q1, Q3: 7.1, 13.3) years, 131 participants developed incident dementia, of whom 98 were diagnosed with Alzheimer's disease. The highest tertile of IGFBP-2, compared to the lowest tertile, was associated with an increased risk of incident all-cause dementia (hazard ratio [HR] 2.89, 95% CI 1.63-5.13) and Alzheimer's disease (HR 3.63, 95% CI 1.76-7.50) in multivariable analysis. Higher circulating IGFBP2 levels were also cross-sectionally associated with poorer performance on tests of abstract reasoning but not with MRI-based outcomes. After adding plasma IGFBP-2 levels to a conventional dementia prediction model, 32% of individuals with dementia were correctly assigned a higher predicted risk, while 8% of individuals without dementia were correctly assigned a lower predicted risk (overall net reclassification improvement index, 0.40, 95% CI 0.22-0.59). INTERPRETATION: Elevated circulating IGFBP-2 levels were associated with an increased risk of both all-cause dementia and Alzheimer's disease. Addition of IGFBP2 plasma levels to a model of traditional risk factors significantly improved dementia risk classification. Manipulation of insulin-like growth factor signaling via IGFBP-2 may be a promising therapeutic target for dementia.

5.
PLoS One ; 14(7): e0218111, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31283791

RESUMO

Late onset Alzheimer's disease is the most common form of dementia for which about 30 susceptibility loci have been reported. The aim of the current study is to identify novel genes associated with Alzheimer's disease using the largest up-to-date reference single nucleotide polymorphism (SNP) panel, the most accurate imputation software and a novel gene-based analysis approach which tests for patterns of association within genes, in the powerful genome-wide association dataset of the International Genomics of Alzheimer's Project Consortium, comprising over 7 million genotypes from 17,008 Alzheimer's cases and 37,154 controls. In addition to earlier reported genes, we detected three novel gene-wide significant loci PPARGC1A (p = 2.2 × 10-6), RORA (p = 7.4 × 10-7) and ZNF423 (p = 2.1 × 10-6). PPARGC1A and RORA are involved in circadian rhythm; circadian disturbances are one of the earliest symptoms of Alzheimer's disease. PPARGC1A is additionally linked to energy metabolism and the generation of amyloid beta plaques. RORA is involved in a variety of functions apart from circadian rhythm, such as cholesterol metabolism and inflammation. The ZNF423 gene resides in an Alzheimer's disease-specific protein network and is likely involved with centrosomes and DNA damage repair.

6.
Ann Neurol ; 86(3): 463-467, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31271449

RESUMO

Higher plasma total-tau level is associated with incident dementia, but its relationship with stroke risk is unknown. In this prospective community-based study, we evaluated plasma total-tau level as a biomarker of stroke risk in 2,794 Framingham Heart Study participants. Persons with plasma total-tau levels in the top quintile, versus the bottom 4, had an increased risk of incident stroke over a mean follow-up of 8.3 years (hazard ratio = 2.01; 95% confidence interval = 1.32-3.08) following adjustments for age, sex, and stroke risk factors. Our findings demonstrate that plasma total-tau relates to the risk of stroke in a community sample. ANN NEUROL 2019;86:463-467.

7.
PLoS One ; 14(7): e0219668, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31356640

RESUMO

BACKGROUND: Apolipoprotein E is a glycoprotein best known as a mediator and regulator of lipid transport and uptake. The APOE-ε4 allele has long been associated with increased risks of Alzheimer's disease and mortality, but the effect of the less prevalent APOE-ε2 allele on diseases in the elderly and survival remains elusive. METHODS: We aggregated data of 38,537 individuals of European ancestry (mean age 65.5 years; 55.6% women) from six population-based cohort studies (Rotterdam Study, AGES-Reykjavik Study, Cardiovascular Health Study, Health-ABC Study, and the family-based Framingham Heart Study and Long Life Family Study) to determine the association of APOE, and in particular APOE-ε2, with survival in the population. RESULTS: During a mean follow-up of 11.7 years, 17,021 individuals died. Compared with homozygous APOE-ε3 carriers, APOE-ε2 carriers were at lower risk of death (hazard ratio,95% confidence interval: 0.94,0.90-0.99; P = 1.1*10-2), whereas APOE-ε4 carriers were at increased risk of death (HR 1.17,1.12-1.21; P = 2.8*10-16). APOE was associated with mortality risk in a dose-dependent manner, with risk estimates lowest for homozygous APOE-ε2 (HR 0.89,0.74-1.08), and highest for homozygous APOE-ε4 (HR 1.52,1.37-1.70). After censoring for dementia, effect estimates remained similar for APOE-ε2 (HR 0.95,0.90-1.01), but attenuated for APOE-ε4 (HR 1.07,1.01-1.12). Results were broadly similar across cohorts, and did not differ by age or sex. APOE genotype was associated with baseline lipid fractions (e.g. mean difference(95%CI) in LDL(mg/dL) for ε2 versus ε33: -17.1(-18.1-16.0), and ε4 versus ε33: +5.7(4.8;6.5)), but the association between APOE and mortality was unaltered after adjustment for baseline LDL or cardiovascular disease. Given the European ancestry of the study population, results may not apply to other ethnicities. CONCLUSION: Compared with APOE-ε3, APOE-ε2 is associated with prolonged survival, whereas mortality risk is increased for APOE-ε4 carriers. Further collaborative efforts are needed to unravel the role of APOE and in particular APOE-ε2 in health and disease.

8.
J Am Heart Assoc ; 8(14): e012141, 2019 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-31303106

RESUMO

Background Excess transmission of pressure pulsatility caused by increased arterial stiffness may incur microcirculatory damage in end organs (target organ damage [TOD] ) and, in turn, elevate risk for cardiovascular disease ( CVD ) events. Methods and Results We related arterial stiffness measures (carotid-femoral pulse wave velocity, mean arterial pressure, central pulse pressure) to the prevalence and incidence of TOD (defined as albuminuria and/or echocardiographic left ventricular hypertrophy) in up to 6203 Framingham Study participants (mean age 50±15 years, 54% women). We then related presence of TOD to incident CVD in multivariable Cox regression models without and with adjustment for arterial stiffness measures. Cross-sectionally, greater arterial stiffness was associated with a higher prevalence of TOD (adjusted odds ratios ranging from 1.23 to 1.54 per SD increment in arterial stiffness measure, P<0.01). Prospectively, increased carotid-femoral pulse wave velocity was associated with incident albuminuria (odds ratio per SD 1.28, 95% CI, 1.02-1.61; P<0.05), whereas higher mean arterial pressure and central pulse pressure were associated with incident left ventricular hypertrophy (odds ratio per SD 1.37 and 1.45, respectively; P<0.01). On follow-up, 297 of 5803 participants experienced a first CVD event. Presence of TOD was associated with a 33% greater hazard of incident CVD (95% CI , 0-77%; P<0.05), which was attenuated upon adjustment for baseline arterial stiffness measures by 5-21%. Conclusions Elevated arterial stiffness is associated with presence of TOD and may partially mediate the relations of TOD with incident CVD . Our observations in a large community-based sample suggest that mitigating arterial stiffness may lower the burden of TOD and, in turn, clinical CVD .

9.
Cereb Cortex ; 2019 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-31240317

RESUMO

Exposures to life stressors accumulate across the lifespan, with possible impact on brain health. Little is known, however, about the mechanisms mediating age-related changes in brain structure. We use a lifespan sample of participants (n = 21 251; 4-97 years) to investigate the relationship between the thickness of cerebral cortex and the expression of the glucocorticoid- and the mineralocorticoid-receptor genes (NR3C1 and NR3C2, respectively), obtained from the Allen Human Brain Atlas. In all participants, cortical thickness correlated negatively with the expression of both NR3C1 and NR3C2 across 34 cortical regions. The magnitude of this correlation varied across the lifespan. From childhood through early adulthood, the profile similarity (between NR3C1/NR3C2 expression and thickness) increased with age. Conversely, both profile similarities decreased with age in late life. These variations do not reflect age-related changes in NR3C1 and NR3C2 expression, as observed in 5 databases of gene expression in the human cerebral cortex (502 donors). Based on the co-expression of NR3C1 (and NR3C2) with genes specific to neural cell types, we determine the potential involvement of microglia, astrocytes, and CA1 pyramidal cells in mediating the relationship between corticosteroid exposure and cortical thickness. Therefore, corticosteroids may influence brain structure to a variable degree throughout life.

10.
Liver Int ; 39(9): 1713-1721, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31155826

RESUMO

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is common and has been recently related to brain health. We aimed to assess the relationships of NAFLD and its severity, using the NAFLD fibrosis score (NFS), with cognitive performance. METHODS: Framingham study Offspring and 3rd generation participants were included if they attended exams 9 (2002-2008) and 2 (2008-2011), respectively, were free of dementia and stroke, and did not have excessive alcohol intake. Between 2008 and 2011, participants underwent Multi-detector computed tomography scans of the abdomen to determine NAFLD diagnosis and the NFS was used to categorize the severity of fibrosis. Cross-sectional relationships of NAFLD and the NFS with cognitive testing of memory, abstract reasoning, visual perception, attention and executive function were assessed, while adjusting for multiple cardiometabolic variables including visceral adipose tissue, diabetes and insulin resistance. RESULTS: Of the 1287 participants (mean age = 61±12 years, 48% men), 378 (29%) had NAFLD. The presence of NAFLD was not associated with cognitive function. However, among those with NAFLD (mean age = 61±12 years; 58% men), high compared to low risk of advanced fibrosis was associated with poorer performance on similarities (ß = -2.22 ± 0.83; P = 0.009) and trail-making B minus A (ß = -0.11 ± 0.05; P = 0.028), independently of potential confounders. CONCLUSIONS: Participants with high risk of advanced fibrosis may have poorer cognitive function compared to those with low risk, particularly in executive function and abstract reasoning. Future findings are necessary to evaluate the value of the NFS as a biomarker that predicts cognitive impairment and dementia and to explore the role of hepatic fibrosis in brain health.

11.
JAMA Neurol ; 2019 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-31180460

RESUMO

Importance: Previous genome-wide association studies of common variants identified associations for Alzheimer disease (AD) loci evident only among individuals with particular APOE alleles. Objective: To identify APOE genotype-dependent associations with infrequent and rare variants using whole-exome sequencing. Design, Setting, and Participants: The discovery stage included 10 441 non-Hispanic white participants in the Alzheimer Disease Sequencing Project. Replication was sought in 2 independent, whole-exome sequencing data sets (1766 patients with AD, 2906 without AD [controls]) and a chip-based genotype imputation data set (8728 patients with AD, 9808 controls). Bioinformatics and functional analyses were conducted using clinical, cognitive, neuropathologic, whole-exome sequencing, and gene expression data obtained from a longitudinal cohort sample including 402 patients with AD and 647 controls. Data were analyzed between March 2017 and September 2018. Main Outcomes and Measures: Score, Firth, and sequence kernel association tests were used to test the association of AD risk with individual variants and genes in subgroups of APOE ε4 carriers and noncarriers. Results with P ≤ 1 × 10-5 were further evaluated in the replication data sets and combined by meta-analysis. Results: Among 3145 patients with AD and 4213 controls lacking ε4 (mean [SD] age, 83.4 [7.6] years; 4363 [59.3.%] women), novel genome-wide significant associations were obtained in the discovery sample with rs536940594 in AC099552 (odds ratio [OR], 88.0; 95% CI, 9.08-852.0; P = 2.22 × 10-7) and rs138412600 in GPAA1 (OR, 1.78; 95% CI, 1.44-2.2; meta-P = 7.81 × 10-8). GPAA1 was also associated with expression in the brain of GPAA1 (ß = -0.08; P = .03) and its repressive transcription factor, FOXG1 (ß = 0.13; P = .003), and global cognition function (ß = -0.53; P = .009). Significant gene-wide associations (threshold P ≤ 6.35 × 10-7) were observed for OR8G5 (P = 4.67 × 10-7), IGHV3-7 (P = 9.75 × 10-16), and SLC24A3 (P = 2.67 × 10-12) in 2377 patients with AD and 706 controls with ε4 (mean [SD] age, 75.2 [9.6] years; 1668 [54.1%] women). Conclusions and Relevance: The study identified multiple possible novel associations for AD with individual and aggregated rare variants in groups of individuals with and without APOE ε4 alleles that reinforce known and suggest additional pathways leading to AD.

12.
BMJ ; 365: l1855, 2019 05 22.
Artigo em Inglês | MEDLINE | ID: mdl-31122926

RESUMO

OBJECTIVES: To investigate the role of body mass index (BMI), systolic blood pressure, and smoking behaviour in explaining the effect of education on the risk of cardiovascular disease outcomes. DESIGN: Mendelian randomisation study. SETTING: UK Biobank and international genome-wide association study data. PARTICIPANTS: Predominantly participants of European ancestry. EXPOSURE: Educational attainment, BMI, systolic blood pressure, and smoking behaviour in observational analysis, and randomly allocated genetic variants to instrument these traits in mendelian randomisation. MAIN OUTCOMES MEASURE: The risk of coronary heart disease, stroke, myocardial infarction, and cardiovascular disease (all subtypes; all measured in odds ratio), and the degree to which this is mediated through BMI, systolic blood pressure, and smoking behaviour respectively. RESULTS: Each additional standard deviation of education (3.6 years) was associated with a 13% lower risk of coronary heart disease (odds ratio 0.86, 95% confidence interval 0.84 to 0.89) in observational analysis and a 37% lower risk (0.63, 0.60 to 0.67) in mendelian randomisation analysis. As a proportion of the total risk reduction, BMI was estimated to mediate 15% (95% confidence interval 13% to 17%) and 18% (14% to 23%) in the observational and mendelian randomisation estimates, respectively. Corresponding estimates were 11% (9% to 13%) and 21% (15% to 27%) for systolic blood pressure and 19% (15% to 22%) and 34% (17% to 50%) for smoking behaviour. All three risk factors combined were estimated to mediate 42% (36% to 48%) and 36% (5% to 68%) of the effect of education on coronary heart disease in observational and mendelian randomisation analyses, respectively. Similar results were obtained when investigating the risk of stroke, myocardial infarction, and cardiovascular disease. CONCLUSIONS: BMI, systolic blood pressure, and smoking behaviour mediate a substantial proportion of the protective effect of education on the risk of cardiovascular outcomes and intervening on these would lead to reductions in cases of cardiovascular disease attributable to lower levels of education. However, more than half of the protective effect of education remains unexplained and requires further investigation.


Assuntos
Doenças Cardiovasculares/etiologia , Escolaridade , Adulto , Idoso , Pressão Sanguínea , Índice de Massa Corporal , Feminino , Humanos , Masculino , Análise da Randomização Mendeliana , Pessoa de Meia-Idade , Análise Multivariada , Razão de Chances , Fatores de Risco , Fumar/efeitos adversos , Fatores Socioeconômicos , Reino Unido
13.
Stroke ; 50(6): 1558-1560, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31084341

RESUMO

Background and Purpose- Stroke at midlife has a disproportionately large impact on disability-adjusted life-years lost. Ischemic stroke incidence may be increasing at this age. We investigated long-term trends in ischemic stroke incidence and changes in stroke risk factors in a community sample stratified by stroke onset at middle and older age. Methods- In the Framingham Study, surveillance for incident stroke is ongoing since 1948. We examined age-adjusted and sex-adjusted 10-year incidence of ischemic stroke using Cox models in persons aged 35 to 54 and ≥55 years at start of follow-up. Tests for linear trend were performed over 4 epochs, controlling for the distance in time between intervals. Further, we calculated the mean 10-year risk of stroke at each epoch and for both age groups, based on vascular risk factors from the Framingham Stroke Risk Profile. Results- There were 153, 197, 176, and 165 incident ischemic strokes within each epoch beginning in 1962 (n=3966), 1971 (n=5779), 1987 (n=5133), and 1998 (n=6964). Most ischemic strokes at midlife (n=71) were because of atherosclerotic brain infarction (n=50) or cardioembolism (n=19). Using the risk in the 1962 epoch as the reference, the risk of ischemic stroke at midlife did not significantly decline (hazard ratio, 0.87; 95% CI, 0.74-1.02; P trend =0.09). Incidence of ischemic stroke declined in the older group (hazard ratio, 0.82; 95% CI, 0.77-0.88; P trend <0.001). Between epochs 1 and 4, the average 10-year risk of stroke, as estimated by the Framingham Stroke Risk Profile, declined by 0.7% at midlife and 1.1% at older age. Conclusions- Long-term rates of ischemic stroke declined in our community sample; the decline was greater in older as compared with younger adults. Early prevention, focused on modification of cardiovascular risk factors, is important to see sustained declines in stroke incidence and mortality at midlife.

14.
BMJ ; 365: l1495, 2019 04 17.
Artigo em Inglês | MEDLINE | ID: mdl-30995986

RESUMO

OBJECTIVE: To examine whether physical inactivity is a risk factor for dementia, with attention to the role of cardiometabolic disease in this association and reverse causation bias that arises from changes in physical activity in the preclinical (prodromal) phase of dementia. DESIGN: Meta-analysis of 19 prospective observational cohort studies. DATA SOURCES: The Individual-Participant-Data Meta-analysis in Working Populations Consortium, the Inter-University Consortium for Political and Social Research, and the UK Data Service, including a total of 19 of a potential 9741 studies. REVIEW METHOD: The search strategy was designed to retrieve individual-participant data from prospective cohort studies. Exposure was physical inactivity; primary outcomes were incident all-cause dementia and Alzheimer's disease; and the secondary outcome was incident cardiometabolic disease (that is, diabetes, coronary heart disease, and stroke). Summary estimates were obtained using random effects meta-analysis. RESULTS: Study population included 404 840 people (mean age 45.5 years, 57.7% women) who were initially free of dementia, had a measurement of physical inactivity at study entry, and were linked to electronic health records. In 6.0 million person-years at risk, we recorded 2044 incident cases of all-cause dementia. In studies with data on dementia subtype, the number of incident cases of Alzheimer's disease was 1602 in 5.2 million person-years. When measured <10 years before dementia diagnosis (that is, the preclinical stage of dementia), physical inactivity was associated with increased incidence of all-cause dementia (hazard ratio 1.40, 95% confidence interval 1.23 to 1.71) and Alzheimer's disease (1.36, 1.12 to 1.65). When reverse causation was minimised by assessing physical activity ≥10 years before dementia onset, no difference in dementia risk between physically active and inactive participants was observed (hazard ratios 1.01 (0.89 to 1.14) and 0.96 (0.85 to 1.08) for the two outcomes). Physical inactivity was consistently associated with increased risk of incident diabetes (hazard ratio 1.42, 1.25 to 1.61), coronary heart disease (1.24, 1.13 to 1.36), and stroke (1.16, 1.05 to 1.27). Among people in whom cardiometabolic disease preceded dementia, physical inactivity was non-significantly associated with dementia (hazard ratio for physical activity assessed >10 before dementia onset 1.30, 0.79 to 2.14). CONCLUSIONS: In analyses that addressed bias due to reverse causation, physical inactivity was not associated with all-cause dementia or Alzheimer's disease, although an indication of excess dementia risk was observed in a subgroup of physically inactive individuals who developed cardiometabolic disease.


Assuntos
Demência/epidemiologia , Síndrome Metabólica/epidemiologia , Comportamento Sedentário , Demência/etiologia , Humanos , Incidência , Síndrome Metabólica/etiologia , Estudos Observacionais como Assunto , Fatores de Risco , Reino Unido/epidemiologia
15.
JAMA Netw Open ; 2(4): e192745, 2019 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-31002329

RESUMO

Importance: Dementia risk may be attenuated by physical activity (PA); however, the specific activity levels optimal for dementia prevention are unclear. Moreover, most older adults are unable to meet the nationally recommended PA guidelines, set at 150 minutes of moderate to vigorous PA per week. Objective: To assess the association of total steps walked per day and total dose (intensity × duration) of PA with brain volumes on magnetic resonance imaging (MRI) among Framingham Heart Study participants. Design, Setting, and Participants: This cross-sectional, community-based cohort study of the association of accelerometry-determined PA with brain MRI measures in Framingham, Massachusetts, included the Framingham Heart Study third-generation (examination 2, 2008-2011) and offspring (examination 9, 2011-2014) cohorts. Of 4021 participants who agreed to wear an accelerometer and had valid data (≥10 hours/day for ≥3 days), 1667 participants who did not undergo brain MRI (n = 1604) or had prevalent dementia or stroke (n = 63) were excluded. Data analysis began in 2016 and was completed in February 2019. Exposures: Physical activity achieved using accelerometry-derived total activity (steps per day) and 2 intensity levels (light intensity and moderate to vigorous intensity). Main Outcomes and Measures: Differences in total brain volume and other MRI markers of brain aging. Results: The study sample of 2354 participants had a mean (SD) age of 53 (13) years, 1276 (54.2%) were women, and 1099 (46.7%) met the PA guidelines. Incremental light-intensity PA was associated with higher total brain volume; each additional hour of light-intensity PA was associated with approximately 1.1 years less brain aging (ß estimate, 0.22; SD, 0.07; P = .003). Among individuals not meeting the PA guidelines, each hour of light-intensity PA (ß estimate, 0.28; SD, 0.11; P = .01) and achieving 7500 steps or more per day (ß estimate, 0.44; SD, 0.18; P = .02) were associated with higher total brain volume, equivalent to approximately 1.4 to 2.2 years less brain aging. After adjusting for light-intensity PA, neither increasing moderate to vigorous PA levels nor meeting the threshold moderate to vigorous PA level recommended by the PA guidelines were significantly associated with total brain volume. Conclusions and Relevance: Every additional hour of light-intensity PA was associated with higher brain volumes, even among individuals not meeting current PA guidelines. These data are consistent with the notion that the potential benefits of PA on brain aging may accrue at a lower, more achievable level of intensity or duration.

16.
JAMA Neurol ; 76(5): 598-606, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-30830207

RESUMO

Importance: Blood-based biomarkers have the potential to improve the identification of persons with the greatest dementia risk for inclusion in dementia prevention trials through low-cost and minimally invasive screening. Objective: To investigate the use of plasma total tau as a blood biomarker for dementia and related endophenotypes. Design, Setting, and Participants: This prospective cohort study used data from the US community-based Framingham Heart Study with replication in the Memento study, a multicenter cohort of persons with mild cognitive impairment or subjective cognitive complaints recruited from memory clinics across France. Total tau levels were measured from stored plasma samples in Framingham Heart Study participants during 2004 to 2011. Dementia follow-up occurred across a median of 6 years (interquartile range, 5-8 years) for persons 65 years and older who were dementia free at baseline. Plasma and/or cerebrospinal fluid samples were obtained from Memento study participants from April 19, 2011, to June 22, 2016. Dementia follow-up took place over a median of 4 years (interquartile range, 3-5 years). Data analysis was performed from January to November 2018. Exposures: Plasma total tau level measured using single-molecule array technology. Main Outcomes and Measures: Incidence of dementia of any cause (all dementia) and dementia due to clinical Alzheimer disease (AD dementia). Results: Among the 1453 participants in the Framingham dementia study sample, the mean (SD) age was 75 (7) years; 792 (54.5%) were female. Among the 367 individuals in the replication cohort, the mean (SD) age was 69 (9) years; 217 (59.1%) were female. Of 134 cases of incident all dementia in the Framingham sample, 105 were AD dementia. After adjustment for age and sex, each SD unit increase in the log of plasma total tau level was associated with a 35% increase in AD dementia risk (hazard ratio [HR], 1.35; 95% CI, 1.10-1.67). The addition of plasma total tau to a model including age and sex improved the stratification of participants for risk of AD dementia (net reclassification improvement, 0.382; 95% CI, 0.030-0.716). Higher plasma total tau level was associated with poorer cognition across 7 cognitive tasks (P < .05) and smaller hippocampi (hippocampal volume: ß [SE] = 0.002 [0.001]; P = .003) as well as neurofibrillary tangles (ß [SE] = 0.95 [0.45]; P = .04) and microinfarcts (odds ratio, 3.04; 95% CI, 1.26-7.37) at autopsy. In the replication cohort, plasma total tau level weakly correlated with cerebrospinal fluid total tau level (Spearman correlation coefficient, 0.16; P = .07), but plasma total tau was at least as strongly associated with incident AD dementia as cerebrospinal fluid total tau (log plasma total tau: HR, 2.33; 95% CI, 1.00-5.48; log cerebrospinal fluid total tau: HR, 2.14; 95% CI, 1.33-3.44) after adjustment for age and sex. Conclusions and Relevance: The findings suggest that plasma total tau levels may improve the prediction of future dementia, are associated with dementia endophenotypes, and may be used as a biomarker for risk stratification in dementia prevention trials.

17.
PLoS One ; 14(3): e0213321, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30830941

RESUMO

BACKGROUND: Fibroblast growth factor 23 is an emerging vascular biomarker, recently associated with cerebral small vessel disease and poor cognition in patients on dialysis. It also interacts with klotho, an anti-aging and cognition enhancing protein. OBJECTIVE: To determine if circulating Fibroblast growth factor 23 (FGF23) is associated with new-onset cognitive outcomes in a community-based cohort of cognitively healthy adults with long-term follow-up. METHODS: We measured serum FGF23 levels in 1537 [53% women, mean age 68.7 (SD 5.7)] dementia-free Framingham Offspring participants at their 7th quadrennial examination (1998-2001), and followed these participants for the development of clinical all-cause dementia and Alzheimer's disease (AD). Secondary outcomes included MRI-based structural brain measures, and neurocognitive test performance at exam 7. RESULTS: During a median (Q1, Q3) 12-year (7.0, 13.3) follow up, 122 (7.9%) participants developed dementia, of whom 91 (5.9%) had AD. Proportional-hazards regression analysis, adjusted for age, sex, education, systolic blood pressure, antihypertensive medication, prevalent cardiovascular disease, diabetes mellitus, smoking status and apoE ε4 carrier status, revealed that higher serum FGF23 levels were associated with an increased risk of incident dementia and AD (Hazard ratio [HR] per 1 standard deviation increment in inverse transformed FGF23 level 1.25, 95% CI 1.02-1.53, and 1.32, 95% CI 1.04-1.69, respectively). There was no significant interaction according to presence/absence of significant renal impairment (eGFR <30 versus ≥30ml/min) and risk of dementia (based on 1537; p = 0.97). CONCLUSIONS: Higher circulating FGF23 is associated with an increased risk of dementia, suggesting that FGF23-related biological pathways may play a role in the development of dementia.

18.
Brain ; 142(4): 1009-1023, 2019 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-30859180

RESUMO

We report a composite extreme phenotype design using distribution of white matter hyperintensities and brain infarcts in a population-based cohort of older persons for gene-mapping of cerebral small vessel disease. We demonstrate its application in the 3C-Dijon whole exome sequencing (WES) study (n = 1924, nWESextremes = 512), with both single variant and gene-based association tests. We used other population-based cohort studies participating in the CHARGE consortium for replication, using whole exome sequencing (nWES = 2,868, nWESextremes = 956) and genome-wide genotypes (nGW = 9924, nGWextremes = 3308). We restricted our study to candidate genes known to harbour mutations for Mendelian small vessel disease: NOTCH3, HTRA1, COL4A1, COL4A2 and TREX1. We identified significant associations of a common intronic variant in HTRA1, rs2293871 using single variant association testing (Pdiscovery = 8.21 × 10-5, Preplication = 5.25 × 10-3, Pcombined = 4.72 × 10-5) and of NOTCH3 using gene-based tests (Pdiscovery = 1.61 × 10-2, Preplication = 3.99 × 10-2, Pcombined = 5.31 × 10-3). Follow-up analysis identified significant association of rs2293871 with small vessel ischaemic stroke, and two blood expression quantitative trait loci of HTRA1 in linkage disequilibrium. Additionally, we identified two participants in the 3C-Dijon cohort (0.4%) carrying heterozygote genotypes at known pathogenic variants for familial small vessel disease within NOTCH3 and HTRA1. In conclusion, our proof-of-concept study provides strong evidence that using a novel composite MRI-derived phenotype for extremes of small vessel disease can facilitate the identification of genetic variants underlying small vessel disease, both common variants and those with rare and low frequency. The findings demonstrate shared mechanisms and a continuum between genes underlying Mendelian small vessel disease and those contributing to the common, multifactorial form of the disease.

19.
Neurology ; 92(10): e1086-e1097, 2019 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-30709966

RESUMO

OBJECTIVE: We investigated differences in the anatomical distribution of cerebral microbleeds (CMBs) on MRI, hypothesized to indicate the type of underlying cerebral small vessel disease (SVD), between Eastern and Western general populations. METHODS: We analyzed data from 11 studies identified by a PubMed search between 1996 and April 2014 according to the Preferred Reporting Items for a Systematic Review and Meta-analysis of Individual Participant Data. Study quality measures indicated low or medium risk of bias. We included stroke-free participants from populations aged between 55 and 75 years, categorized by geographic location (Eastern or Western). We categorized CMB distribution (strictly lobar, deep and/or infratentorial [D/I], or mixed [i.e., CMBs located in both lobar and D/I regions]). We tested the hypothesis that Eastern and Western populations have different anatomical distributions of CMBs using multivariable mixed effects logistic regression analyses adjusted for age, sex, and hypertension and clustering by institution. RESULTS: Among 8,595 stroke-free individuals (mean age [SD] 66.7 [5.6] years; 48% male; 42% from a Western population), 624 (7.3%) had CMBs (strictly lobar in 3.1%; D/I or mixed in 4.2%). In multivariable mixed effects models, Eastern populations had higher odds of D/I or mixed CMBs (adjusted odds ratio 2.78, 95% confidence interval [CI] 1.77-4.35) compared to Western populations. Eastern populations had a higher number of D/I or mixed CMBs (adjusted prevalence ratio 2.83, 95% CI 1.27-6.31). CONCLUSIONS: Eastern and Western general populations have different anatomical distributions of CMBs, suggesting differences in the spectrum of predominant underlying SVDs, with potential implications for SVD diagnosis and treatment.

20.
J Diabetes Res ; 2019: 2718465, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30729134

RESUMO

Aims: Circulating insulin-like growth factor- (IGF-) 1, vascular endothelial growth factor (VEGF), and brain-derived neurotrophic factor (BDNF) levels are often lower in individuals with diabetes mellitus (DM) and are important for repairing vascular and neuronal dysfunction. The purpose of this investigation was to determine the cross-sectional relations of physical activity to circulating concentrations of IGF-1, VEGF, and BDNF in individuals with and without DM. Methods: In 1730 participants from the Framingham Offspring Study examination cycle 7, including those with DM (n = 179, mean age 64 years, 39% women) and without DM (n = 1551, mean age 60 years, 46% women), we related self-reported physical activity variables to circulating concentrations of IGF-1, VEGF, and BDNF using linear multivariable regression models. We also tested for interactions by age. Participants with prevalent cardiovascular disease, stroke, and dementia or taking hormone replacement therapy were excluded. Results: In participants with DM, more ambulatory physical activity was associated with higher IGF-1 levels (ß ± standard error (SE) = 0.22 ± 0.08, p = 0.009), and more total physical activity was related to higher BDNF levels (ß ± SE = 0.18 ± 0.08, p = 0.035), but physical activity was not significantly related to circulating VEGF. In participants without DM, no associations were observed. Moreover, in the examination of interactions by age, the association of ambulatory physical activity with IGF-1 levels was only observed in older adults with DM (age ≥ 60 years, ß ± SE = 0.23 ± 0.11, p = 0.042) but not in middle-aged adults with DM (age < 60 years, ß ± SE = 0.06 ± 0.13, p = 0.645). Conclusion: Our results suggest that more physical activity is associated with higher circulating IGF-1 and BDNF in participants with DM. These results, dissecting interactions by both age and DM status, may also help to explain some of the inconsistent results in studies relating physical activity to growth and neurotrophic factors.


Assuntos
Fator Neurotrófico Derivado do Encéfalo/sangue , Diabetes Mellitus/sangue , Exercício/fisiologia , Fator de Crescimento Insulin-Like I/metabolismo , Fator A de Crescimento do Endotélio Vascular/sangue , Idoso , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Autorrelato , Inquéritos e Questionários
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