Browsing by Author "Sands, Laura P."
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- Change in Reports of Unmet Need For Help with ADL or Mobility DisabilitiesSands, Laura P.; Yuan, Miao; Xie, Yimeng; Hong, Yili (Virginia Tech, 2015)Self-care (SC) and Mobility (MO) disabled older adults require the help of others to successfully complete daily tasks. Thirty percent of respondents to the 2011 NHATS survey reported unmet need for one or more SC or MO disabilities. Reports of unmet need for disabilities is associated with: Future hospitalization¹ Readmission² Emergency Department use³ Mortality⁴ Little is known about patterns of unmet need over time, especially the degree to which unmet need resolves, varies, or begins. Determination of predictors of change in unmet need status would inform the development of interventions to reduce unmet need.
- Corporate Default Predictions and Methods for Uncertainty QuantificationsYuan, Miao (Virginia Tech, 2016-08-01)Regarding quantifying uncertainties in prediction, two projects with different perspectives and application backgrounds are presented in this dissertation. The goal of the first project is to predict the corporate default risks based on large-scale time-to-event and covariate data in the context of controlling credit risks. Specifically, we propose a competing risks model to incorporate exits of companies due to default and other reasons. Because of the stochastic and dynamic nature of the corporate risks, we incorporate both company-level and market-level covariate processes into the event intensities. We propose a parsimonious Markovian time series model and a dynamic factor model (DFM) to efficiently capture the mean and correlation structure of the high-dimensional covariate dynamics. For estimating parameters in the DFM, we derive an expectation maximization (EM) algorithm in explicit forms under necessary constraints. For multi-period default risks, we consider both the corporate-level and the market-level predictions. We also develop prediction interval (PI) procedures that synthetically take uncertainties in the future observation, parameter estimation, and the future covariate processes into account. In the second project, to quantify the uncertainties in the maximum likelihood (ML) estimators and compute the exact tolerance interval (TI) factors regarding the nominal confidence level, we propose algorithms for two-sided control-the-center and control-both-tails TI for complete or Type II censored data following the (log)-location-scale family of distributions. Our approaches are based on pivotal properties of ML estimators of parameters for the (log)-location-scale family and utilize the Monte-Carlo simulations. While for Type I censored data, only approximate pivotal quantities exist. An adjusted procedure is developed to compute the approximate factors. The observed CP is shown to be asymptotically accurate by our simulation study. Our proposed methods are illustrated using real-data examples.
- Evidence that Community-Based Long-Term Care is Preventive CareSands, Laura P. (Virginia Tech, 2014)This presentation outlines the benefits of community-based long-term care, including reduced hospitalization rates.
- The impact of interventions on appointment and clinical outcomes for individuals with diabetes: a systematic reviewNuti, Lynn; Turkcan, Ayten; Lawley, Mark A.; Zhang, Lingsong; Sands, Laura P.; McComb, Sara (2015-09-02)Background Successful diabetes disease management involves routine medical care with individualized patient goals, self-management education and on-going support to reduce complications. Without interventions that facilitate patient scheduling, improve attendance to provider appointments and provide patient information to provider and care team, preventive services cannot begin. This review examines interventions based upon three focus areas: 1) scheduling the patient with their provider; 2) getting the patient to their appointment, and; 3) having patient information integral to their diabetes care available to the provider. This study identifies interventions that improve appointment management and preparation as well as patient clinical and behavioral outcomes. Methods A systematic review of the literature was performed using MEDLINE, CINAHL and the Cochrane library. Only articles in English and peer-reviewed articles were chosen. A total of 77 articles were identified that matched the three focus areas of the literature review: 1) on the schedule, 2) to the visit, and 3) patient information. These focus areas were utilized to analyze the literature to determine intervention trends and identify those with improved diabetes clinical and behavioral outcomes. Results The articles included in this review were published between 1987 and 2013, with 46 of them published after 2006. Forty-two studies considered only Type 2 diabetes, 4 studies considered only Type 1 diabetes, 15 studies considered both Type 1 and Type 2 diabetes, and 16 studies did not mention the diabetes type. Thirty-five of the 77 studies in the review were randomized controlled studies. Interventions that facilitated scheduling patients involved phone reminders, letter reminders, scheduling when necessary while monitoring patients, and open access scheduling. Interventions used to improve attendance were letter reminders, phone reminders, short message service (SMS) reminders, and financial incentives. Interventions that enabled routine exchange of patient information included web-based programs, phone calls, SMS, mail reminders, decision support systems linked to evidence-based treatment guidelines, registries integrated with electronic medical records, and patient health records. Conclusions The literature review showed that simple phone and letter reminders for scheduling or prompting of the date and time of an appointment to more complex web-based multidisciplinary programs with patient self-management can have a positive impact on clinical and behavioral outcomes for diabetes patients. Multifaceted interventions aimed at appointment management and preparation during various phases of the medical outpatient care process improves diabetes disease management.
- Individual and Partner Exercise Status and Cognitive Function in Older AdultsRatliff, Kathryn Georgette (Virginia Tech, 2022-06-01)The present study used a linear mixed model analytic approach to assess the association between a combined respondent and spousal exercise score and cognitive outcomes of older adult respondents drawn from a nationally representative dataset, The Health and Retirement Study. Informed by the Scaffolding Theory of Aging and Cognition (STAC), the present study sought to understand the role of both an individual and their spouse's aerobic physical activity in an individual's cognitive outcomes and trajectories. Utilizing longitudinal survey data collected across twelve years (N=3,189), the combined exercise status of a married couple was found to be a significant predictor of cognitive outcomes; when an interaction between time and couple exercise status was included in the model, this was also found to be a significant predictor of four specific cognitive outcomes. The highest cognitive benefit was identified among individuals where both they and their partner participated in the recommended amount of aerobic physical activity, suggesting an additive effect. These findings and their implications are discussed further.
- Injury prevention for older adults: A dataset of safety concern narratives from online reviews of mobility-related productsRestrepo, Felipe; Mali, Namrata; Sands, Laura P.; Abrahams, Alan; Goldberg, David M.; White, Janay; Prieto, Laura; Ractham, Peter; Gruss, Richard; Zaman, Nohel; Ehsani, Johnathon P. (Elsevier, 2022-06)Older adults are among the fastest-growing demographic groups in the United States, increasing by over a third this past decade. Consequently, the older adult consumer prod-uct market has quickly become a multi-billion-dollar in-dustry in which millions of products are sold every year. However, the rapidly growing market raises the poten-tial for an increasing number of product safety concerns and consumer product-related injuries among older adults. Recent manufacturer and consumer injury prevention efforts have begun to turn towards online reviews, as these provide valuable information from which actionable, timely intelligence can be derived and used to detect safety concerns and prevent injury. The presented dataset contains 1966 curated online product reviews from consumers, equally distributed between safety concerns and non-concerns, pertaining to product categories typically intended for older adults. Identified safety concerns were manually sub-coded across thirteen dimensions designed to capture relevant aspects of the consumer's experience with the purchased product, facilitate the safety concern identification and sub-classification process, and serve as a gold-standard, balanced dataset for text classifier learning. (c) 2022 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)
- The interplay of life stressors and coping resources: Implications for healthOgletree, Aaron M. (Virginia Tech, 2018-04-30)Adults aged 50 years and older are a growing segment of the population and are more likely than their younger counterparts to experience significant stressors such as the death of a relative or friend, onset of chronic conditions, and increased health burden. The current studies use Pearlin's stress process model to evaluate the impact of these stressors on outcomes of depression. Study 1 used Wave 1 data from the ORANJ BOWL research panel of 5,688 New Jersey residents aged 50 and older to explore the relationship between relational life events, private religious practices, and depressed mood. Cross-sectional structural equation modeling was used to evaluate these relationships. Results showed that relational life events had a significant positive influence on depressive symptoms and this relationship was partially mediated by private religious practices. Findings indicate that non-personal life events are important sources of stress that may otherwise be overlooked when assessing risk factors among older adults. Study 2 used data from 640 men from the Research on Older Adults with HIV (ROAH) study to evaluate the impact of HIV-related health burden on depressed mood and to assess the mitigating effects of social support adequacy. Structural equation modeling showed that greater health burden was associated with more depressive symptoms; this relationship was significantly partially mediated by emotional support adequacy, which was a measure of unmet social need. Findings indicate that health burden has a cumulative impact on psychological health and programs and supports that target social wellness can improve this relationship. These studies point to the importance of understanding sources of risk and resilience among older people and in an attempt to improve overall health outcomes.
- Open Research/Open Data Forum: Transparency, Sharing, and Reproducibility in ScholarshipPotter, Peter J.; Chen, Daniel; DePauw, Karen P.; Morton, Sally C.; Petters, Jonathan L.; Radcliffe, David H.; Sands, Laura P. (Virginia Tech. University Libraries, 2017-04-10)Join our panelists for a discussion on challenges and opportunities related to sharing and using open data in research, including meeting funder and journal guidelines: Daniel Chen (Ph.D. candidate in Genetics, Bioinformatics, and Computational Biology) Karen DePauw (Vice President and Dean for Graduate Education) Sally Morton (Dean, College of Science) Jon Petters (Data Management Consultant, University Libraries) David Radcliffe (English) Laura Sands (Center for Gerontology)
- Peritraumatic Stress From a Disaster Increases Risk for Onset of Chronic Diseases Among Older AdultsSands, Laura P.; Do, Quyen; Du, Pang; Pruchno, Rachel (Oxford University Press, 2022-01-01)Background and objectives: Our understanding of the impact of disaster exposure on the physical health of older adults is largely based on hospital admissions for acute illnesses in the weeks following a disaster. Studies of longer-term outcomes have centered primarily on mental health. Missing have been studies examining whether exposure to disaster increases the risk for the onset of chronic diseases. We examined the extent to which 2 indicators of disaster exposure (geographic exposure and peritraumatic stress) were associated with new onset of cardiovascular disease, diabetes, arthritis, and lung disease to improve our understanding of the long-term physical health consequences of disaster exposure. Research design and methods: We linked self-reported data collected prior to and following Hurricane Sandy from a longitudinal panel study with Medicare data to assess time to new onset of chronic diseases in the 4 years after the hurricane. Results: We found that older adults who reported high levels of peritraumatic stress from Hurricane Sandy had more than twice the risk of experiencing a new diagnosis of lung disease, diabetes, and arthritis in the 4 years after the hurricane compared to older adults who did not experience high levels of peritraumatic stress. Geographic proximity to the hurricane was not associated with these outcomes. Analyses controlled for known risk factors for the onset of chronic diseases, including demographic, psychosocial, and health risks. Discussion and implications: Findings reveal that physical health effects of disaster-related peritraumatic stress extend beyond the weeks and months after a disaster and include new onset of chronic diseases that are associated with loss of functioning and early mortality.
- Resilience among Older Adults with Cognitive Impairment and Informal CaregiversKim, Sujee (Virginia Tech, 2017-06-07)The concept of resilience, which indicates people's capability of using resources in difficult circumstances in order to reduce or prevent negative effects and achieve positive outcomes, has given a new perspective to the scientific literature on the experience of late-life memory loss and the experience of caring for persons with memory loss. The current research was guided by incorporation of resilience into the stress process model for assessing personal and caregiver burden associated with mild and more severe memory loss. I conducted two studies to investigate the association of protective factors with the well-being of people with dementia or mild cognitive impairment and their caregivers. The first study focused on the well-being of older persons with dementia (PwDs). I employed data from a large national sample of older adults to examine how the perceived social cohesion of neighborhoods affects quality of life among people with and without cognitive impairment in conjunction with their engagement in valued leisure activities. Findings revealed that, regardless of cognitive health status, all participants who perceived high neighborhood social cohesion reported better quality of life along with more participation in valued activities. However, PwDs reported significantly lower perceived neighborhood social cohesion, less involvement in valued activities, and poorer quality of life than persons without cognitive impairment. The second study focused on the well-being of caregivers for older persons with mild cognitive impairment (PwMCIs). I used dyadic data from families dealing with mild cognitive impairment to examine how well-being of caregivers for PwMCIs differed according to whether PwMCI-caregiver dyads had similar or different perceptions of the PwMCIs' cognitive impairment severity. Caregivers reported lower caregiving burden when they and PwMCIs had a similar cognitive impairment representation, or when caregivers rated the PwMCIs’ cognitive functioning more positively than the PwMCIs rated themselves. Also, PwMCIs’ and caregivers' perceptions, and their concordance or discrepancy in those perceptions, varied across the multiple domains related to MCI symptoms. These findings demonstrate that care dyads' perception of MCI-related deficits is not a unitary construct, and that the context of PwMCIs’ and caregivers’ dyadic illness appraisals is significantly associated with the caregivers' well-being. Taken together, the results of these two studies illustrate the value of considering resilience processes in people with cognitive impairment and their caregivers. Examining dimensions of resilience, in association with assessment of the intersecting effects of personal, interpersonal, and environmental factors, provides additional information about the effects of cognitive impairment on older adults’ well-being and the effects of assisting someone with cognitive impairment on caregiver well-being.
- Statistical Methods for Multivariate Functional Data Clustering, Recurrent Event Prediction, and Accelerated Degradation Data AnalysisJin, Zhongnan (Virginia Tech, 2019-09-12)In this dissertation, we introduce three projects in machine learning and reliability applications after the general introductions in Chapter 1. The first project concentrates on the multivariate sensory data, the second project is related to the bivariate recurrent process, and the third project introduces thermal index (TI) estimation in accelerated destructive degradation test (ADDT) data, in which an R package is developed. All three projects are related to and can be used to solve certain reliability problems. Specifically, in Chapter 2, we introduce a clustering method for multivariate functional data. In order to cluster the customized events extracted from multivariate functional data, we apply the functional principal component analysis (FPCA), and use a model based clustering method on a transformed matrix. A penalty term is imposed on the likelihood so that variable selection is performed automatically. In Chapter 3, we propose a covariate-adjusted model to predict next event in a bivariate recurrent event system. Inspired by geyser eruptions in Yellowstone National Park, we consider two event types and model their event gap time relationship. External systematic conditions are taken account into the model with covariates. The proposed covariate adjusted recurrent process (CARP) model is applied to the Yellowstone National Park geyser data. In Chapter 4, we compare estimation methods for TI. In ADDT, TI is an important index indicating the reliability of materials, when the accelerating variable is temperature. Three methods are introduced in TI estimations, which are least-squares method, parametric model and semi-parametric model. An R package is implemented for all three methods. Applications of R functions are introduced in Chapter 5 with publicly available ADDT datasets. Chapter 6 includes conclusions and areas for future works.
- Subjective Memory Decline Predicts Incident Cognitive Impairment among White -- but Not Black or Hispanic -- Older AdultsFerraro, Kenneth F.; Sauerteig-Rolston, Madison R.; Barnes, Lisa L.; Friedman, Elliot; Sands, Laura P.; Thomas, Patricia A. (Oxford University Press, 2022-06-18)Background and objectives: This study investigates whether subjective memory decline in a racially diverse sample of older adults without cognitive impairment at baseline is associated with incident cognitive impairment during a 12-year follow-up period. Research design and methods: With panel data from a national sample (N=9,244) of cognitively-intact Black, White, and Hispanic Americans 65 years or older in 2004, we examine if subjective memory decline is associated with the loss of normal cognition by 2016. Cognitive status was assessed every two years with a modified version of the Telephone Interview for Cognitive Status to identify the transition from normal cognition to cognitive impairment. Results: Estimates from Weibull accelerated failure-time models reveal that subjective memory decline is associated with earlier incident cognitive impairment (time ratio = 0.96, p<.05). In subsequent models stratified by race-ethnicity, this association was evident among White respondents (time ratio = 0.95, p<.01) but not among Black, US-born Hispanic, or foreign-born Hispanic respondents. Discussion and implications: Given that the prognostic validity of subjective memory decline differs by race and ethnicity, caution is warranted when using it as a screening or clinical tool in diverse populations.
- Understanding and Addressing Older Adults’ Needs During COVID-19Sands, Laura P.; Albert, Steven M.; Suitor, Jill J. (Oxford University Press, 2020-06-02)Four months have passed since the World Health Organization (WHO) identified coronavirus disease 2019 (COVID-19) as a public health emergency, and 3 months since it declared the outbreak of COVID-19 a pandemic. WHO posted guidelines to reduce the spread of COVID- 19, including isolating those with the virus, quarantining those exposed to the virus, and social distancing. These guidelines have been adopted across the globe, and there is evidence that following these guidelines slows transmission of the disease. Some have suggested that cases have reached a plateau, yet these conclusions are based on data drawn from reports of identified cases, which are not necessarily representative of all cases of COVID-19. This is problematic for designing guidelines and policies that are intended to protect the health of the entire population and the health of those who may be particularly vulnerable to COVID-19, including older adults. The pandemic has created difficulties for all, so we must be thoughtful about our pathway for returning to a life that is not threatened by COVID-19. Guidelines and policies for charting that pathway should be based on high-quality data, scientific knowledge, and ethical decision making.