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Pradeepkiran JA, Baig J, Islam MA, Kshirsagar S, Reddy PH. Amyloid-β and Phosphorylated Tau are the Key Biomarkers and Predictors of Alzheimer's Disease. Aging Dis 2024:AD.2024.0286. [PMID: 38739937 DOI: 10.14336/ad.2024.0286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Accepted: 04/24/2024] [Indexed: 05/16/2024] Open
Abstract
Alzheimer's disease (AD) is a age-related neurodegenerative disease and is a major public health concern both in Texas, US and Worldwide. This neurodegenerative disease is mainly characterized by amyloid-beta (Aβ) and phosphorylated Tau (p-Tau) accumulation in the brains of patients with AD and increasing evidence suggests that these are key biomarkers in AD. Both Aβ and p-tau can be detected through various imaging techniques (such as positron emission tomography, PET) and cerebrospinal fluid (CSF) analysis. The presence of these biomarkers in individuals, who are asymptomatic or have mild cognitive impairment can indicate an increased risk of developing AD in the future. Furthermore, the combination of Aβ and p-tau biomarkers is often used for more accurate diagnosis and prediction of AD progression. Along with AD being a neurodegenerative disease, it is associated with other chronic conditions such as cardiovascular disease, obesity, depression, and diabetes because studies have shown that these comorbid conditions make people more vulnerable to AD. In the first part of this review, we discuss that biofluid-based biomarkers such as Aβ, p-Tau in cerebrospinal fluid (CSF) and Aβ & p-Tau in plasma could be used as an alternative sensitive technique to diagnose AD. In the second part, we discuss the underlying molecular mechanisms of chronic conditions linked with AD and how they affect the patients in clinical care.
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Affiliation(s)
| | - Javaria Baig
- Internal Medicine Department, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | - Md Ariful Islam
- Internal Medicine Department, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | - Sudhir Kshirsagar
- Internal Medicine Department, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | - P Hemachandra Reddy
- Internal Medicine Department, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
- Pharmacology & Neuroscience Department, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
- Neurology Department, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
- Speech, Language and Hearing Sciences Departments, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
- Public Health Department, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
- Nutritional Sciences Department, College of Human Sciences, Texas Tech University, Lubbock, TX 79409, USA
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Sible IJ, Jang JY, Blanken AE, Alitin JPM, Engstrom A, Dutt S, Marshall AJ, Kapoor A, Shenasa F, Gaubert A, Nguyen A, Ferrer F, Bradford DR, Rodgers KE, Mather M, Duke Han S, Nation DA. Short-term blood pressure variability and brain functional network connectivity in older adults. NEUROIMAGE. REPORTS 2024; 4:100198. [PMID: 38699510 PMCID: PMC11064972 DOI: 10.1016/j.ynirp.2024.100198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/05/2024]
Abstract
Background Blood pressure variability is increasingly linked with cerebrovascular disease and Alzheimer's disease, independent of mean blood pressure levels. Elevated blood pressure variability is also associated with attenuated cerebrovascular reactivity, which may have implications for functional hyperemia underpinning brain network connectivity. It remains unclear whether blood pressure variability is related to functional network connectivity. We examined relationships between beat-to-beat blood pressure variability and functional connectivity in brain networks vulnerable to aging and Alzheimer's disease. Methods 53 community-dwelling older adults (mean [SD] age = 69.9 [7.5] years, 62.3% female) without history of dementia or clinical stroke underwent continuous blood pressure monitoring and resting state fMRI scan. Blood pressure variability was calculated as variability independent of mean. Functional connectivity was determined by resting state fMRI for several brain networks: default, salience, dorsal attention, fronto-parietal, and language. Multiple linear regression examined relationships between short-term blood pressure variability and functional network connectivity. Results Elevated short-term blood pressure variability was associated with lower functional connectivity in the default network (systolic: standardized ß = -0.30 [95% CI -0.59, -0.01], p = .04). There were no significant associations between blood pressure variability and connectivity in other functional networks or between mean blood pressure and functional connectivity in any network. Discussion Older adults with elevated short-term blood pressure variability exhibit lower resting state functional connectivity in the default network. Findings support the role of blood pressure variability in neurovascular dysfunction and Alzheimer's disease. Blood pressure variability may represent an understudied early vascular risk factor for neurovascular dysfunction relevant to Alzheimer's disease, with potential therapeutic implications.
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Affiliation(s)
- Isabel J. Sible
- Department of Psychology, University of Southern California, Los Angeles, CA 90089, USA
| | - Jung Yun Jang
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, CA 92697, USA
| | - Anna E. Blanken
- San Francisco Veterans Affairs Health Care System, San Francisco, CA, 94121, USA
- Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, CA, 94158, USA
| | - John Paul M. Alitin
- Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA
| | - Allie Engstrom
- Department of Psychological Science, University of California Irvine, Irvine, CA 92697, USA
| | - Shubir Dutt
- Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, CA, 94158, USA
| | - Anisa J. Marshall
- Department of Psychology, University of Southern California, Los Angeles, CA 90089, USA
| | - Arunima Kapoor
- Department of Psychological Science, University of California Irvine, Irvine, CA 92697, USA
| | - Fatemah Shenasa
- Department of Psychological Science, University of California Irvine, Irvine, CA 92697, USA
| | - Aimée Gaubert
- Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA
| | - Amy Nguyen
- Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA
| | - Farrah Ferrer
- Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA
| | - David R. Bradford
- Center for Innovation in Brain Science, Department of Pharmacology, The University of Arizona, Tucson, AZ, 85721, USA
| | - Kathleen E. Rodgers
- Center for Innovation in Brain Science, Department of Pharmacology, The University of Arizona, Tucson, AZ, 85721, USA
| | - Mara Mather
- Department of Psychology, University of Southern California, Los Angeles, CA 90089, USA
- Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA
| | - S. Duke Han
- Department of Psychology, University of Southern California, Los Angeles, CA 90089, USA
- Department of Family Medicine, Keck School of Medicine of University of Southern California, Alhambra, CA 91803, USA
| | - Daniel A. Nation
- Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA
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Sible IJ, Nation DA. Blood Pressure Variability and Plasma Alzheimer's Disease Biomarkers in the SPRINT Trial. J Alzheimers Dis 2024; 97:1851-1860. [PMID: 38306042 DOI: 10.3233/jad-230930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2024]
Abstract
Background Recent observational studies suggest higher blood pressure (BP) variability (BPV) is associated with Alzheimer's disease (AD) biomarkers amyloid-beta (Aβ) and tau. Less is known about relationships in interventional cohorts with strictly controlled mean BP levels. Objective Investigate the longitudinal relationship between BPV and change in plasma AD biomarkers under standard versus intensive BP treatment. Methods In this post hoc analysis of the SPRINT trial, 457 participants (n = 206 in standard group, n = 251 in intensive group) underwent repeated BP measurement between baseline and 12-months follow-up, and venipuncture at baseline and median (IQR) 3.5 (3.0-4.0) years later to determine plasma AD biomarkers total tau and Aβ1-42:Aβ1-40 ratio. BPV was calculated as tertiles of variability independent of mean. Linear mixed models investigated the effect of BPV×time on AD biomarker levels. Results Higher BPV was associated with increased levels of total tau in the standard group (β [95% CI] 1st versus 3rd tertiles of BPV: 0.21 [0.02, 0.41], p = 0.035), but not in the intensive group (β [95% CI] 1st versus 3rd tertiles of BPV: -0.02 [-0.19, 0.16], p = 0.843). BPV was not associated with Aβ 1-42:Aβ 1-40 ratio in either group. Mean BP was not associated with biomarkers. Conclusions Higher BPV was associated with increased plasma total tau under standard BP treatment. Findings add new evidence to prior observational work linking BPV to AD pathophysiology and suggest that, despite strict control of mean BP, BPV remains a risk for pathophysiological change underlying risk for AD.
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Affiliation(s)
- Isabel J Sible
- Department of Psychology, University of Southern California, Los Angeles, CA, USA
| | - Daniel A Nation
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA
- Department of Physiology and Neuroscience, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, CA, USA
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Starmans NLP, Kappelle LJ, Muller M, Staals J, Teunissen CE, Biessels GJ, van der Flier WM, Wolters FJ. Blood Pressure Variability and Plasma Biomarkers of Neuronal Injury and Alzheimer's Disease: A Clinic-Based Study of Patients with Diseases Along the Heart-Brain Axis. J Alzheimers Dis 2024; 99:1207-1215. [PMID: 38788076 PMCID: PMC11191465 DOI: 10.3233/jad-240119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/10/2024] [Indexed: 05/26/2024]
Abstract
Higher blood pressure variability (BPV) predisposes to cognitive decline. To investigate underlying mechanisms, we measured 24-h ambulatory BPV, nocturnal dipping and orthostatic hypotension in 518 participants with vascular cognitive impairment, carotid occlusive disease, heart failure, or reference participants. We determined cross-sectional associations between BPV indices and plasma biomarkers of neuronal injury (neurofilament light chain) and Alzheimer's disease (phosphorylated-tau-181 and Aβ42/Aβ40). None of the BPV indices were significantly associated with any of the biomarkers. Hence, in patients with diseases along the heart-brain axis, we found no evidence for an association between BPV and selected markers of neuronal injury or Alzheimer's disease.
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Affiliation(s)
| | - Laurens Jaap Kappelle
- Department of Neurology and Neurosurgery, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Majon Muller
- Department of Internal Medicine, Geriatrics Section, Amsterdam Cardiovascular Science, Amsterdam University Medical Center (Amsterdam UMC), Amsterdam, The Netherlands
| | - Julie Staals
- Department of Neurology, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University Medical Center, Maastricht, The Netherlands
| | - Charlotte Elisabeth Teunissen
- Department of Clinical Chemistry, Neurochemistry Laboratory, Amsterdam Neuroscience, Amsterdam University Medical Center (Amsterdam UMC), Amsterdam, The Netherlands
| | - Geert Jan Biessels
- Department of Neurology and Neurosurgery, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Wiesje Maria van der Flier
- Department of Neurology, Alzheimer Center Amsterdam, Amsterdam Neuroscience, Amsterdam University Medical Center (Amsterdam UMC), Amsterdam, The Netherlands
- Department of Epidemiology, Amsterdam University Medical Center (Amsterdam UMC), Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Frank Johannes Wolters
- Department of Epidemiology, Erasmus University Medical Center, Rotterdam, The Netherlands
- Department of Radiology and Nuclear Medicine and Alzheimer Center, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - on behalf of the Heart-Brain Connection Consortium
- Department of Neurology and Neurosurgery, University Medical Center Utrecht, Utrecht, The Netherlands
- Department of Internal Medicine, Geriatrics Section, Amsterdam Cardiovascular Science, Amsterdam University Medical Center (Amsterdam UMC), Amsterdam, The Netherlands
- Department of Neurology, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University Medical Center, Maastricht, The Netherlands
- Department of Clinical Chemistry, Neurochemistry Laboratory, Amsterdam Neuroscience, Amsterdam University Medical Center (Amsterdam UMC), Amsterdam, The Netherlands
- Department of Neurology, Alzheimer Center Amsterdam, Amsterdam Neuroscience, Amsterdam University Medical Center (Amsterdam UMC), Amsterdam, The Netherlands
- Department of Epidemiology, Amsterdam University Medical Center (Amsterdam UMC), Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
- Department of Epidemiology, Erasmus University Medical Center, Rotterdam, The Netherlands
- Department of Radiology and Nuclear Medicine and Alzheimer Center, Erasmus University Medical Center, Rotterdam, The Netherlands
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Sible IJ, Nation DA. 24-Hour Blood Pressure Variability Via Ambulatory Monitoring and Risk for Probable Dementia in the SPRINT Trial. J Prev Alzheimers Dis 2024; 11:684-692. [PMID: 38706284 PMCID: PMC11060998 DOI: 10.14283/jpad.2024.35] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 09/17/2023] [Indexed: 05/07/2024]
Abstract
BACKGROUND Blood pressure variability is an emerging risk factor for dementia, independent and oftentimes beyond mean blood pressure levels. Recent evidence from interventional cohorts with rigorously controlled mean blood pressure levels suggest blood pressure variability over months to years remains a risk for dementia, but no prior studies have investigated relationships with blood pressure variability over shorter time periods. OBJECTIVES To investigate the potential effect of ambulatory blood pressure variability on the rate of cognitive outcomes under intensive vs standard blood pressure lowering. DESIGN Post hoc analysis of the randomized, controlled, open-label Systolic Blood Pressure Intervention Trial clinical trial. SETTING Multisite Systolic Blood Pressure Intervention Trial. PARTICIPANTS 793 participants at increased risk for cardiovascular disease and without history of dementia at study randomization. INTERVENTION Standard (<140 mmHg systolic blood pressure target) vs intensive (<120 mmHg systolic blood pressure target) lowering of mean blood pressure. MEASUREMENTS 24-hour ambulatory blood pressure monitoring 27 months after treatment randomization (standard vs intensive) and follow-up cognitive testing. Intraindividual blood pressure variability was calculated as the average real variability over 24-hour, daytime, and nighttime periods. Participants were categorized into 3 adjudicated clinical outcomes: no cognitive impairment, mild cognitive impairment, probable dementia. Cox proportional hazards models examined the potential effect of ambulatory blood pressure variability on the rate of cognitive outcomes under intensive vs standard blood pressure lowering. Associations with mean blood pressure were also explored. RESULTS Higher systolic 24-hour blood pressure variability was associated with increased risk for probable dementia in the standard group (adjusted hazard ratio [HR]: 2.56 [95% CI 1.16, 5.62], p = 0.019) but not in the intensive group (HR: 0.54 [95% CI 0.24, 1.23], p = 0.141). Similar findings were observed with daytime systolic blood pressure variability but not nighttime blood pressure variability. Mean blood pressure was not associated with cognitive outcomes. CONCLUSIONS Higher systolic 24-hour and daytime blood pressure variability via ambulatory monitoring is associated with risk for dementia under standard blood pressure treatment. Findings support prior evidence that blood pressure variability remains a risk for dementia despite strict control of mean blood pressure levels.
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Affiliation(s)
- I J Sible
- Daniel A. Nation, Ph.D., Associate Professor, University of Southern California, Leonard Davis School of Gerontology, 3715 McClintock Ave, Los Angeles, CA 90089,
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Lohman T, Sible I, Kapoor A, Engstrom AC, Alitin JP, Gaubert A, Rodgers KE, Bradford D, Mather M, Han SD, Thayer JF, Nation DA. Blood pressure variability, central autonomic network dysfunction and cerebral small vessel disease in APOE4 carriers. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.12.13.23299556. [PMID: 38168394 PMCID: PMC10760290 DOI: 10.1101/2023.12.13.23299556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Background Increased blood pressure variability (BPV) is a risk factor for cerebral small vessel disease (CSVD) and neurodegeneration, independent of age and average blood pressure, particularly in apolipoprotein E4 (APOE4) carriers. However, it remains uncertain whether BPV elevation is a cause or a consequence of vascular brain injury, or to what degree injury to the central autonomic network (CAN) may contribute to BPV-associated risk in APOE4 carriers. Methods Independently living older adults (n=70) with no history of stroke or dementia were recruited from the community and underwent 5 minutes of resting beat-to-beat blood pressure monitoring, genetic testing, and brain MRI. Resting BPV, APOE genotype, CSVD burden on brain MRI, and resting state CAN connectivity by fMRI were analyzed. Causal mediation and moderation analysis evaluated BPV and CAN effects on CSVD in APOE4 carriers (n=37) and non-carriers (n=33). Results Higher BPV was associated with the presence and extent of CSVD in APOE4 carriers, but not non-carriers, independent of CAN connectivity (B= 18.92, P= .02), and CAN connectivity did not mediate the relationship between BPV and CSVD. In APOE4 carriers, CAN connectivity moderated the relationship between BPV and CSVD, whereby BPV effects on CSVD were greater in those with lower CAN connectivity (B= 36.43, P= .02). Conclusions Older APOE4 carriers with higher beat-to-beat BPV exhibit more extensive CSVD, independent of average blood pressure, and the strength of CAN connectivity does not mediate these effects. Findings suggest increased BPV is more likely a cause, not a consequence, of CSVD. BPV is more strongly associated with CSVD in APOE4 carriers with lower rsCAN connectivity, suggesting CAN dysfunction and BPV elevation may have synergistic effects on CSVD. Further studies are warranted to understand the interplay between BPV and CAN function in APOE4 carriers.
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Affiliation(s)
- Trevor Lohman
- University of Southern California Leonard Davis School of Gerontology, Los Angeles, CA, USA
| | - Isabel Sible
- Department of Psychology, University of Southern California, Los Angeles, CA, USA
| | - Arunima Kapoor
- Department of Psychological Science, University of California, Irvine, Irvine, CA, USA
| | - Allison C Engstrom
- Department of Psychological Science, University of California, Irvine, Irvine, CA, USA
| | - John Paul Alitin
- University of Southern California Leonard Davis School of Gerontology, Los Angeles, CA, USA
| | - Aimee Gaubert
- University of Southern California Leonard Davis School of Gerontology, Los Angeles, CA, USA
| | - Kathleen E Rodgers
- Center for Innovations in Brain Science, Department of Pharmacology, University of Arizona, Tucson, AZ, USA
| | - David Bradford
- Center for Innovations in Brain Science, Department of Pharmacology, University of Arizona, Tucson, AZ, USA
| | - Mara Mather
- University of Southern California Leonard Davis School of Gerontology, Los Angeles, CA, USA
| | - S Duke Han
- University of Southern California Leonard Davis School of Gerontology, Los Angeles, CA, USA
| | - Julian F Thayer
- Department of Psychological Science, University of California, Irvine, Irvine, CA, USA
| | - Daniel A Nation
- University of Southern California Leonard Davis School of Gerontology, Los Angeles, CA, USA
- University of Southern California Keck School of Medicine, Los Angeles, CA, USA
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Kim H, Alvin Ang TF, Thomas RJ, Lyons MJ, Au R. Long-term blood pressure patterns in midlife and dementia in later life: Findings from the Framingham Heart Study. Alzheimers Dement 2023; 19:4357-4366. [PMID: 37394941 PMCID: PMC10597747 DOI: 10.1002/alz.13356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 05/08/2023] [Accepted: 05/09/2023] [Indexed: 07/04/2023]
Abstract
INTRODUCTION Long-term blood pressure (BP) measures, such as visit-to-visit BP variability (BPV) and cumulative BP, are strong indicators of cardiovascular risks. This study modeled up to 20 years of BP patterns representative of midlife by using BPV and cumulative BP, then examined their associations with development of dementia in later life. METHODS For 3201 individuals from the Framingham Heart Study, multivariate logistic regression analyses were performed to examine the association between long-term BP patterns during midlife and the development of dementia (ages ≥ 65). RESULTS After adjusting for covariates, every quartile increase in midlife cumulative BP was associated with a sequential increase in the risk of developing dementia (e.g., highest quartile of cumulative systolic blood pressure had approximately 2.5-fold increased risk of all-cause dementia). BPV was not significantly associated with dementia. DISCUSSION Findings suggest that cumulative BP over the course of midlife predicts risk of dementia in later life. HIGHLIGHTS Long-term blood pressure (BP) patterns are strong indicators of vascular risks. Cumulative BP and BP variability (BPV) were used to reflect BP patterns across midlife. High cumulative BP in midlife is associated with increased dementia risk. Visit-to-visit BPV was not associated with the onset of dementia.
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Affiliation(s)
- Hyun Kim
- Dept. of Psychological & Brain Sciences, Boston University, 900 Commonwealth Ave # 2, Boston, MA 02215, USA
- Framingham Heart Study, Boston University School of Medicine, 72 E. Concord St Housman (R), Boston MA 02118
| | - Ting Fang Alvin Ang
- Framingham Heart Study, Boston University School of Medicine, 72 E. Concord St Housman (R), Boston MA 02118
- Department of Anatomy and Neurobiology, Boston University School of Medicine, 72 E. Concord St Housman (R), Boston MA 02118
| | - Robert J. Thomas
- Department of Medicine, Division of Pulmonary, Critical Care & Sleep, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue Shapiro 7 Boston, MA 02215
| | - Michael J. Lyons
- Dept. of Psychological & Brain Sciences, Boston University, 900 Commonwealth Ave # 2, Boston, MA 02215, USA
| | - Rhoda Au
- Framingham Heart Study, Boston University School of Medicine, 72 E. Concord St Housman (R), Boston MA 02118
- Department of Anatomy and Neurobiology, Boston University School of Medicine, 72 E. Concord St Housman (R), Boston MA 02118
- Dept. of Neurology, Medicine and Alzheimer’s Disease Research Center, Boston University School of Medicine, 72 E. Concord St, Boston MA 02118
- Dept. of Epidemiology, Boston University School of Public Health, 715 Albany St.Boston, MA 02118
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