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5 LIfestyle for BRAin Health (LIBRA) Modifiable Factors Risk Score and Concussion History Associations with Cognition in Older Former National Football League Players.
- Benjamin L Brett, Neelum T Aggarwal, Avinash Chandran, Zachary Y Kerr, Samuel R Walton, J.D. DeFreese, Kevin M Guskiewicz, Ruben J Echemendia, William P Meehan III, Michael A McCrea, Rebekah Mannix
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- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 305-306
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Objective:
Traumatic brain injury is one of several recognized risk factors for cognitive decline and neurodegenerative disease. Currently, risk scores involving modifiable risk/protective factors for dementia have not incorporated head injury history as part of their overall weighted risk calculation. We investigated the association between the LIfestyle for BRAin Health (LIBRA) risk score with odds of mild cognitive impairment (MCI) diagnosis and cognitive function in older former National Football League (NFL) players, both with and without the influence of concussion history.
Participants and Methods:Former NFL players, ages ≥ 50 (N=1050; mean age=61.1±5.4-years), completed a general health survey including self-reported medical history and ratings of function across several domains. LIBRA factors (weighted value) included cardiovascular disease (+1.0), hypertension (+1.6), hyperlipidemia (+1.4), diabetes (+1.3), kidney disease (+1.1), cigarette use history (+1.5), obesity (+1.6), depression (+2.1), social/cognitive activity (-3.2), physical inactivity (+1.1), low/moderate alcohol use (-1.0), healthy diet (-1.7). Within Group 1 (n=761), logistic regression models assessed the association of LIBRA scores and independent contribution of concussion history with the odds of MCI diagnosis. A modified-LIBRA score incorporated concussion history at the level planned contrasts showed significant associations across concussion history groups (0, 1-2, 3-5, 6-9, 10+). The weighted value for concussion history (+1.9) within the modified-LIBRA score was based on its proportional contribution to dementia relative to other LIBRA risk factors, as proposed by the 2020 Lancet Commission Report on Dementia Prevention. Associations of the modified-LIBRA score with odds of MCI and cognitive function were assessed via logistic and linear regression, respectively, in a subset of the sample (Group 2; n=289) who also completed the Brief Test of Adult Cognition by Telephone (BTACT). Race was included as a covariate in all models.
Results:The median LIBRA score in the Group 1 was 1.6(IQR= -1, 3.6). Standard and modified-LIBRA median scores were 1.1(IQR= -1.3, 3.3) and 2(IQR= -0.4, 4.6), respectively, within Group 2. In Group 1, LIBRA score was significantly associated with odds of MCI diagnosis (odds ratio[95% confidence interval]=1.27[1.19, 1.28], p <.001). Concussion history provided additional information beyond LIBRA scores and was independently associated with odds of MCI; specifically, odds of MCI were higher among those with 6-9 (Odds Ratio[95% confidence interval]; OR=2.54[1.21, 5.32], p<.001), and 10+ (OR=4.55;[2.21, 9.36], p<.001) concussions, compared with those with no prior concussions. Within Group 2, the modified-LIBRA score was associated with higher odds of MCI (OR=1.61[1.15, 2.25]), and incrementally improved model information (0.04 increase in Nagelkerke R2) above standard LIBRA scores in the same model. Modified-LIBRA scores were inversely associated with BTACT Executive Function (B=-0.53[0.08], p=.002) and Episodic Memory scores (B=-0.53[0.08], p=.002).
Conclusions:Numerous modifiable risk/protective factors for dementia are reported in former professional football players, but incorporating concussion history may aid the multifactorial appraisal of cognitive decline risk and identification of areas for prevention and intervention. Integration of multi-modal biomarkers will advance this person-centered, holistic approach toward dementia reduction, detection, and intervention.
2 The Longitudinal Relationship Between Concussion History, Years of Football Participation, and Alcohol Use Among Former National Football League (NFL) Players: an NFL-LONG Study
- Brittany Lang, Zachary Yukio Kerr, Samuel R Walton, Avinash Chandran, Rebekah Mannix, Landon B Lempke, J D DeFreese, Ruben J Echemendia, Kevin M Guskiewicz, William P Meehan, Michael A McCrea, Benjamin L Brett
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- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 114-115
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Objective:
It has been posited that alcohol use may confound the association between greater concussion history and poorer neurobehavioral functioning. However, while greater alcohol use is positively correlated with neurobehavioral difficulties, the association between alcohol use and concussion history is not well understood. Therefore, this study investigated the cross-sectional and longitudinal associations between cumulative concussion history, years of contact sport participation, and health-related/psychological factors with alcohol use in former professional football players across multiple decades.
Participants and Methods:Former professional American football players completed general health questionnaires in 2001 and 2019, including demographic information, football history, concussion/medical history, and health-related/psychological functioning. Alcohol use frequency and amount was reported for three timepoints: during professional career (collected retrospectively in 2001), 2001, and 2019. During professional career and 2001 alcohol use frequency included none, 1-2, 3-4, 5-7 days/week, while amount included none, 12, 3-5, 6-7, 8+ drinks/occasion. For 2019, frequency included never, monthly or less, 2-4 times/month, 2-3 times/week, >4 times/week, while amount included none, 1-2, 3-4, 5-6, 7-9, 10+ drinks/occasion. Scores on a screening measure for Alcohol Use Disorder (CAGE) were also available at during professional career and 2001 timepoints. Concussion history was recorded in 2001 and binned into five groups: 0, 1-2, 3-5, 6-9, 10+. Depression and pain interference were assessed via PROMIS measures at all timepoints. Sleep disturbance was assessed in 2001 via separate instrument and with PROMIS Sleep Disturbance in 2019. Spearman’s rho correlations tested associations between concussion history and years of sport participation with alcohol use across timepoints, and whether poor health functioning (depression, pain interference, sleep disturbance) in 2001 and 2019 were associated with alcohol use both within and between timepoints.
Results:Among the 351 participants (Mage=47.86[SD=10.18] in 2001), there were no significant associations between concussion history or years of contact sport participation with CAGE scores or alcohol use frequency/amount during professional career, 2001, or 2019 (rhos=-.072-.067, ps>.05). In 2001, greater depressive symptomology and sleep disturbance were related to higher CAGE scores (rho=.209, p<.001; rho=.176, p<.001, respectively), while greater depressive symptomology, pain interference, and sleep disturbance were related to higher alcohol use frequency (rho=.176, p=.002; rho=.109, p=.045; rho=.132, p=.013, respectively) and amount/occasion (rho=.215, p<.001; rho=.127, p=.020; rho=.153, p=.004, respectively). In 2019, depressive symptomology, pain interference, and sleep disturbance were not related to alcohol use (rhos=-.047-.087, ps>.05). Between timepoints, more sleep disturbance in 2001 was associated with higher alcohol amount/occasion in 2019 (rho=.115, p=.036).
Conclusions:Increased alcohol intake has been theorized to be a consequence of greater concussion history, and as such, thought to confound associations between concussion history and neurobehavioral function later in life. Our findings indicate concussion history and years of contact sport participation were not significantly associated with alcohol use cross-sectionally or longitudinally, regardless of alcohol use characterization. While higher levels of depression, pain interference, and sleep disturbance in 2001 were related to greater alcohol use in 2001, they were not associated cross-sectionally in 2019. Results support the need to concurrently address health-related and psychological factors in the implementation of alcohol use interventions for former NFL players, particularly earlier in the sport discontinuation timeline.
2 Contributions of Cardiovascular Disease Burden and Concussion History on Cognitive Function in Older Former National Football League Players.
- Benjamin L Brett, Alyssa Leitzke, Zachary Y Kerr, Neelum T Aggarwal, Avinash Chandran, Samuel R Walton, Rebekah Mannix, Landon B Lempke, J.D. DeFreese, Ruben J Echemendia, Kevin M Guskiewicz, William P Meehan III, Michael A McCrea
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- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 302-303
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Objective:
Traumatic brain injury and cardiovascular disease (CVD) are modifiable risk factors for cognitive decline and dementia. Greater concussion history can potentially increase risk for cerebrovascular changes associated with cognitive decline and may compound effects of CVD. We investigated the independent and dynamic effects of CVD/risk factor burden and concussion history on cognitive function and odds of mild cognitive impairment (MCI) diagnoses in older former National Football League (NFL) players.
Participants and Methods:Former NFL players, ages 50-70 (N=289; mean age=61.02±5.33 years), reported medical history and completed the Brief Test of Adult Cognition by Telephone (BTACT). CVD/risk factor burden was characterized as ordinal (0-3+) based on the sum of the following conditions: coronary artery disease/myocardial infarction, chronic obstructive pulmonary disease, hypertension, hyperlipidemia, sleep apnea, type-I and II diabetes. Cognitive outcomes included BTACT Executive Function and Episodic Memory Composite Z-scores (standardized on age- and education-based normative data), and the presence of physician diagnosed (self-reported) MCI. Concussion history was discretized into five groups: 0, 1-2, 3-5, 6-9, 10+. Linear and logistic regression models were fit to test independent and joint effects of concussion history and CVD burden on cognitive outcomes and odds of MCI. Race (dichotomized as White and Non-white due to sample distribution) was included in models as a covariate.
Results:Greater CVD burden (unstandardized beta [standard error]; B=-0.10[0.42], p=.013, and race (B=0.622[0.09], p<.001), were associated with lower executive functioning. Compared to those with 0 prior concussions, no significant differences were observed for those with 1-2, 3-5, 6-9, or 10+ prior concussions (ps >.05). Race (B=0.61[.13], p<.001), but not concussion history or CVD burden, was associated with episodic memory. There was a trend for lower episodic memory scores among those with 10+ prior concussion compared to those with no prior concussions (B=-0.49[.25], p=.052). There were no significant differences in episodic memory among those with 1-2, 3-5, or 6-9 prior concussions compared to those with 0 prior concussions (ps>.05). CVD burden (B=0.35[.13], p=.008), race (greater odds in Non-white group; B=0.82[.29], p=.005), and greater concussion history (higher odds of diagnosis in 10+ group compared to those with 0 prior concussions; B=2.19[0.78], p<.005) were associated with higher odds of MCI diagnosis. Significant interaction effects between concussion history and CVD burden were not observed for any outcome (ps >.05).
Conclusions:Lower executive functioning and higher odds of MCI diagnosis were associated with higher CVD burden and race. Very high concussion history (10+) was selectively associated with higher odds of MCI diagnosis. Reduction of these modifiable factors may mitigate adverse outcomes in older contact sport athletes. In former athletes, consideration of CVD burden is particularly pertinent when assessing executive dysfunction, considered to be a common cognitive feature of traumatic encephalopathy syndrome, as designated by the recent diagnostic criteria. Further research should investigate the social and structural determinants contributing to racial disparities in long-term health outcomes within former NFL players.
Richardson and Reynolds number effects on the near field of buoyant plumes: flow statistics and fluxes
- Michael A. Meehan, Peter E. Hamlington
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- Journal of Fluid Mechanics / Volume 961 / 25 April 2023
- Published online by Cambridge University Press:
- 14 April 2023, A7
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The near-field characteristics of highly buoyant plumes, commonly referred to as lazy plumes, remain relatively poorly understood across a range of flow conditions, particularly compared with our understanding of far-field characteristics. Here, we perform fully resolved three-dimensional numerical simulations of round helium plumes to characterize the effects of different inlet Richardson, ${Ri}_0$, and Reynolds, ${Re}_0$, numbers on first- and second-order statistical moments as well as average vertical fluxes in the near field. For sufficiently high ${Re}_0$ at a particular ${Ri}_0$, heavy air can penetrate the core of the plume, reminiscent of spikes in the classical Rayleigh–Taylor instability. In the most turbulent simulation, this penetration becomes so strong that a recirculation zone forms along the centreline of the plume. Vertical fluxes are found to scale linearly with vertical distance from the plume inlet, consistent with experimental and numerical observations (Jiang & Luo, Flow Turbul. Combust., vol. 64, 2000, pp. 43–69; Kaye & Hunt, Intl J. Heat Fluid Flow, vol. 30, 2009, pp. 1099–1105). We analytically derive this linear scaling from the governing equations by making a radial entrainment hypothesis whereby ambient fluid is entrained, on average, only in the radial direction at a finite distance from the inlet. Through this derivation, we identify physical mechanisms that can cause these relationships to remain only approximately valid for the present simulations. Lastly, we identify near-field power-law scaling relations for the flux magnitudes based on ${Ri}_0$, and also examine vertical profiles of the non-dimensional Richardson number flux. Ultimately, insights from the present simulations are used to define near-, intermediate- and far-field regions in buoyant plumes.
Richardson and Reynolds number effects on the near field of buoyant plumes: temporal variability and puffing
- Michael A. Meehan, Nicholas T. Wimer, Peter E. Hamlington
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- Journal of Fluid Mechanics / Volume 950 / 10 November 2022
- Published online by Cambridge University Press:
- 21 October 2022, A24
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Using numerical simulations, we investigate the near-field temporal variability of axisymmetric helium plumes as a function of inlet-based Richardson (${Ri}_0$) and Reynolds (${Re}_0$) numbers. Previous studies have shown that ${Ri}_0$ plays a leading-order role in determining the frequency at which large-scale vortices are produced (commonly called the ‘puffing’ frequency). By contrast, ${Re}_0$ dictates the strength of localized gradients, which are important during the transition from laminar to turbulent flow. The simulations presented here span a range of ${Ri}_0$ and ${Re}_0$, and use adaptive mesh refinement to achieve high spatial resolutions. We find that as ${Re}_0$ increases for a given ${Ri}_0$, the puffing motion undergoes a transition at a critical ${Re}_0$, marking the onset of chaotic dynamics. Moreover, the critical ${Re}_0$ decreases as ${Ri}_0$ increases. When the puffing instability is non-chaotic, time series of different variables are well-correlated, exhibiting only modest changes in the dynamics (including period doubling and flapping). Once the flow becomes chaotic, denser ambient fluid penetrates the core of the plume, similar to penetrating ‘spikes’ formed by Rayleigh–Taylor instabilities, leading to only moderately correlated flow variables. These changes result in a non-trivial dependence of the puffing frequency on ${Re}_0$. Specifically, at sufficiently low ${Re}_0$, the puffing frequency falls below the prediction from Wimer et al. (J. Fluid Mech., vol. 895, 2020). As ${Re}_0$ increases beyond the critical ${Re}_0$, the puffing frequency increases and then drops back down to the predicted scaling. The dependence of the puffing frequency on ${Re}_0$ provides a possible explanation for previously observed changes in the scaling of the puffing frequency for high ${Ri}_0$.
A dominance analysis of subjective cognitive complaint comorbidities in former professional football players with and without mild cognitive impairment
- Benjamin L. Brett, Zachary Yukio Kerr, Avinash Chandran, Samuel Walton, Neelum T. Aggarwal, Katherine Gifford, Rebekah Mannix, J. D. DeFreese, Ruben J. Echemendia, Kevin M. Guskiewicz, William P. Meehan III, Michael A. McCrea
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- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue 6 / July 2023
- Published online by Cambridge University Press:
- 30 August 2022, pp. 582-593
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Objectives:
Subjective cognitive difficulties (SCDs) are associated with factors commonly reported in older adults and former contact sport athletes, regardless of objective cognitive decline. We investigated the relative contribution of these factors to SCD in former National Football League (NFL)-players with and without a diagnosis of mild cognitive impairment (MCI).
Methods:Former NFL players (n = 907) aged ≥ 50 years (mean = 64.7 ± 8.9), with (n = 165) and without (n = 742) a diagnosis of MCI completed health questionnaires. Multivariable regression and dominance analyses determined the relative importance of SCD factors on SCD: 1) depression, 2) anxiety, 3) sleep disturbance, 4) pain interference, 5) ability to participate in social roles and activities, 6) stress-related events, 7) fatigue, 8) concussion history, and 9) education. SCD outcomes included Neuro-QoL Emotional-Behavioral Dyscontrol and the PROMIS Cognitive Function. Fisher’s z-transformation compared comorbid contributing factors to SCD across MCI and non-MCI groups.
Results:Complete dominance of anxiety was established over most comorbid factors across the MCI and non-MCI groups. Fatigue also exhibited complete dominance over most comorbid factors, though its influence in the MCI group was less robust (general dominance). Average contributions to variance accounted for by comorbid factors to ratings of SCD across MCI and non-MCI groups did not statistically differ (Z-statistics <1.96, ps>.05).
Conclusions:Anxiety and fatigue are the most robust factors associated with SCD in former professional football players across various combinations of clinical presentations (different combinations of comorbid factors), regardless of documented cognitive impairment. Self-reported deficits may be less reliable in detecting objective impairment in the presence of these factors, with multidimensional assessment being ideal.
Planetary science and exploration in the deep subsurface: results from the MINAR Program, Boulby Mine, UK
- Samuel J. Payler, Jennifer F. Biddle, Andrew J. Coates, Claire R. Cousins, Rachel E. Cross, David C. Cullen, Michael T. Downs, Susana O. L. Direito, Thomas Edwards, Amber L. Gray, Jac Genis, Matthew Gunn, Graeme M. Hansford, Patrick Harkness, John Holt, Jean-Luc Josset, Xuan Li, David S. Lees, Darlene S. S. Lim, Melissa Mchugh, David Mcluckie, Emma Meehan, Sean M. Paling, Audrey Souchon, Louise Yeoman, Charles S. Cockell
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- Journal:
- International Journal of Astrobiology / Volume 16 / Issue 2 / April 2017
- Published online by Cambridge University Press:
- 20 April 2016, pp. 114-129
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The subsurface exploration of other planetary bodies can be used to unravel their geological history and assess their habitability. On Mars in particular, present-day habitable conditions may be restricted to the subsurface. Using a deep subsurface mine, we carried out a program of extraterrestrial analog research – MINe Analog Research (MINAR). MINAR aims to carry out the scientific study of the deep subsurface and test instrumentation designed for planetary surface exploration by investigating deep subsurface geology, whilst establishing the potential this technology has to be transferred into the mining industry. An integrated multi-instrument suite was used to investigate samples of representative evaporite minerals from a subsurface Permian evaporite sequence, in particular to assess mineral and elemental variations which provide small-scale regions of enhanced habitability. The instruments used were the Panoramic Camera emulator, Close-Up Imager, Raman spectrometer, Small Planetary Linear Impulse Tool, Ultrasonic drill and handheld X-ray diffraction (XRD). We present science results from the analog research and show that these instruments can be used to investigate in situ the geological context and mineralogical variations of a deep subsurface environment, and thus habitability, from millimetre to metre scales. We also show that these instruments are complementary. For example, the identification of primary evaporite minerals such as NaCl and KCl, which are difficult to detect by portable Raman spectrometers, can be accomplished with XRD. By contrast, Raman is highly effective at locating and detecting mineral inclusions in primary evaporite minerals. MINAR demonstrates the effective use of a deep subsurface environment for planetary instrument development, understanding the habitability of extreme deep subsurface environments on Earth and other planetary bodies, and advancing the use of space technology in economic mining.
Contributors
- Edited by Hiltrud Otto, Hebrew University of Jerusalem, Heidi Keller, Universität Osnabrück
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- Book:
- Different Faces of Attachment
- Published online:
- 05 August 2014
- Print publication:
- 17 July 2014, pp x-xv
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