VTechWorks Repository :: Browsing by Author "Almeida, Fabio A."

Browsing by Author "Almeida, Fabio A."

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Beginning A Patient-Centered Approach in the Design of A Diabetes Prevention Program
Seidel, Richard W.; Pardo, Kimberlee A.; Estabrooks, Paul A.; You, Wen; Wall, Sarah S.; Davy, Brenda M.; Almeida, Fabio A. (MDPI, 2014-02-01)
Effectiveness of a Worksite-Based Weight Loss Randomized Controlled Trial: The Worksite Study
Almeida, Fabio A.; You, Wen; Harden, Samantha M.; Blackman, Kacie C. A.; Davy, Brenda M.; Glasgow, Russell E.; Hill, Jennie L.; Linnan, Laura A.; Wall, Sarah S.; Yenerall, Jackie; Zoellner, Jamie M.; Estabrooks, Paul A. (Wiley-Blackwell, 2015-04-01)
Estradiol signaling mediates gender difference in visceral adiposity via autophagy
Tao, Zhipeng; Zheng, Louise D.; Smith, Cayleen; Luo, Jing; Robinson, Alex; Almeida, Fabio A.; Wang, Zongwei; Olumi, Aria F.; Liu, Dongmin; Cheng, Zhiyong (Springer Nature, 2018)
Excessive adiposity (particularly visceral fat mass) increases the risks of developing metabolic syndrome. Women have lower deposit of visceral fat than men, and this pattern becomes diminished postmenopausally, but the underlying mechanism remains largely unknown. Here, we show that the gender difference in visceral fat distribution is controlled by an estradiol–autophagy axis. In C57BL/6J and wild-type control mice, a higher visceral fat mass was detected in the males than in the females, which was associated with lower expression of estrogen receptor α (ERα) and more active autophagy in males vs. females. However, deletion of ERα normalized autophagy activity and abolished the gender difference in visceral adiposity. In line with the adiposity-reducing effect of the ERα–autophagy axis, we found that downregulation of ERα and increased autophagy activity were required for adipogenesis, while induction of estradiol signaling dampened autophagy and drastically prevented adipogenesis. Mechanistically, the estradiol-ERα signaling activated mTOR, which phosphorylated and inhibited ULK1, thereby suppressing autophagy and adipogenesis. Together, our study suggests that the lower visceral adiposity in the females (vs. the males) arises from a more active estradiol-ERα signaling, which tunes down autophagy and adipogenesis.
Feasibility of an Experiential Community Garden and Nutrition Program for Youth Living in Public Housing:Exploring Outcomes from Youth, Parents and Site Leaders
Grier, Karissa Niphore (Virginia Tech, 2014-06-11)
Background: Community gardens have existed in America since the late 1800s and have served multiple purposes from food subsidies to neighborhood beautification. The use of community gardens has grown in popularity and has been recommended as a way to encourage healthy eating habits in youth. Though the health benefits of having a diet high in fruits and vegetables is well known, youth in the United States do not meet recommendations for fruit and vegetable intake. Under-consumption of fruits and vegetables is problematic in youth, as eating habits are established in childhood. Community gardens have been successfully used to improve access, self-efficacy, preference, and consumption of fruits and vegetables. However, few published community garden studies have focused on low socioeconomic youth. The Dan River Partnership for a Healthy Community (DRPHC) was developed according to community-based participatory research (CBPR) principles. With a mission to reduce obesity using healthy lifestyle initiatives, community gardens are an evolving DRPHC initiative. Objective: To evaluate the feasibility (i.e., demand, acceptability, implementation, and limited-effectiveness testing) of a 10-week experiential theory-based gardening and nutrition education program targeting youth living in two public housing sites in the Dan River Region. Methods: Using pre- and post-program questionnaires/interviews, demand and acceptability were measured among youth, parents and site leaders. Implementation was measures via field notes and attendance. Limited-effectiveness was measured among youth using a pre-post design. Three researchers independently coded the qualitative transcripts, met to resolve disagreements, and built consensus through discussion of the codes. Similarly, field notes were reviewed and evaluated for reoccurring themes regarding barriers, facilitators, and other observations. For the quantitative measures, descriptive statistics were used to summarize the variables and Cronbach's alphas used to assess the reliability of each scale at baseline. Overall effects were tested with repeated measures ANOVA. An intent-to-treat analysis using the last observation carried forward method was used. A critical value of .05 was used for significance testing. A standard equation for reporting effect sizes on a single-group, pre-post study design is also reported. Results: Program enrollment included 43 youth, primarily African American. The positive demand and acceptability findings indicate the potential of the program to be used and suitable for the youth, parents, and site leaders. Field notes revealed numerous implementation facilitators and barriers. Youth weekly attendance averaged 4.6 of 10 sessions. Significant improvements (p<0.05) were found for some (e.g., FV asking self-efficacy, overall gardening knowledge, knowledge of MyPlate recommendations), but not all limited-effectiveness measures (e.g., willingness to try FV, FV eating self-efficacy). Study Implications: This study addresses recommendations for utilizing CBPR in community garden efforts and builds on community identified research priorities of the DRPHC. Results demonstrate the feasibility of a gardening and nutrition program targeting youth in public housing. Lessons learned are being used to adapt and strengthen the program for future efforts targeting FV behaviors. Findings will be shared with local community stakeholders and used to adapt and strengthen the program for future efforts in the Dan River Region targeting of fruit and vegetable behaviors.
Fidelity to and comparative results across behavioral interventions evaluated through the RE-AIM framework: a systematic review
Harden, Samantha M.; Gaglio, Bridget; Shoup, Jo A.; Kinney, Kimberlee A.; Johnson, Sallie B.; Brito, Fabiana A.; Blackman, Kacie C. A.; Zoellner, Jamie M.; Hill, Jennie L.; Almeida, Fabio A.; Glasgow, Russell E.; Estabrooks, Paul A. (2015-11-08)
Background The reach, effectiveness, adoption, implementation, and maintenance (RE-AIM) framework was developed to determine potential public health impact of interventions (i.e., programs, policy, and practice). The purpose of this systematic review was to determine (1) comparative results across accurately reported RE-AIM indicators, (2) relevant information when there remains under-reporting or misclassification of data across each dimension, (3) the degree to which authors intervened to improve outcomes related to each dimension, and (4) the number of articles reporting RE-AIM dimensions for a given study. Methods In April 2013, a systematic search of the RE-AIM framework was completed in PubMed, PSYCHInfo, EbscoHost, Web of Science, and Scopus. Evidence was analyzed until January 2015. Results Eighty-two interventions that included empirical data related to at least one of the RE-AIM dimensions were included in the review. Across these interventions, they reached a median sample size of 320 participants (M = 4894 ± 28,256). Summarizing the effectiveness indicators, we found that: the average participation rate was 45 % (±28 %), 89 % of the interventions reported positive changes in the primary outcome and 11 interventions reported broader outcomes (e.g., quality of life). As for individual-level maintenance, 11 % of studies showed effects ≥6 months post-program. Average setting and staff adoption rates were 75 % (±32 %) and 79 % (±28 %), respectively. Interventions reported being delivered as intended (82 % (±16 %)) and 22 % intervention reported adaptations to delivery. There were insufficient data to determine average maintenance at the organizational level. Data on costs associated with each dimension were infrequent and disparate: four studies reported costs of recruitment, two reported intervention costs per participant, and two reported adoption costs. Conclusions The RE-AIM framework has been employed in a variety of populations and settings for the planning, delivery, and evaluation of behavioral interventions. This review highlights inconsistencies in the degree to which authors reported each dimension in its entirety as well as inaccuracies in reporting indicators within each dimension. Further, there are few interventions that aim to improve outcomes related to reach, adoption, implementation, and maintenance.
Fostering Healthy Lifestyles: Assessing the Need and Potential Intervention Strategies for Foster Children
Parks, Serena L. (Virginia Tech, 2012-09-11)
According to recent estimates, approximately 423,773 children in the United States are in foster care (US Department of Health and Human Services, 2011). While research has documented that childhood obesity is high in foster children, the relationship between nutrition, physical activity, weight status of foster children and the foster home environment is unclear. Furthermore, there is a gap in the literature on the capacity of the child welfare system to address obesity among this population nor practical intervention strategies. This dissertation consists of three studies, with the following purposes: 1) assess the current foster care landscape related to the promotion of healthy eating and physical activity through questionnaire based and objective data; 2) examine legislature and training programs that focus on nutrition and physical activity as it relates to foster families; and 3) utilize the Delphi method to begin the development of a potential healthy eating and physical activity intervention for foster care through the recommendation of intervention strategies that could be integrated into the foster care system. These purposes are achieved utilizing a systems-based approach. More specifically, research was conducted through collaboration with several local agencies throughout Virginia. The findings from Study 1 suggest that obesity is prevalent among foster children and foster parents in Virginia and that there are some indications that the foster home environment is related to lifestyle behaviors and weight status, though the relationships were small. Study 2 identified face-to-face trainings targeting foster parents and children (depending on the child's age) as an important and practical method to intervene through regular trainings. Study 3 indicated that there are few federal or local policies that explicitly address physical activity, nutrition, and weight status. A number of recommendations are made for the structure, content, and process of integrating obesity prevention and treatment strategies within the foster care system.
FoxO1 in the regulation of adipocyte autophagy and biology
Liu, Longhua (Virginia Tech, 2016-12-08)
Obesity is a rapidly growing epidemic in the USA and worldwide. While the molecular and cellular mechanism of obesity is incompletely understood, studies have shown that excess adiposity may arise from increased adipogenesis (hyperplasia) and adipocyte size (hypertrophy) . Emerging evidence underscores autophagy as an important mediator of adipogenesis and adiposity. We are interested in the upstream regulator of adipocyte autophagy and how it impacts adipocyte biology. Given that metabolic stress activates transcription factor FoxO1 in obesity, my dissertation project is designed to depict the role of FoxO1 in adipocyte autophagy and biology. We found that FoxO1 upregulation was concomitant with elevation of autophagy activity during adipogenesis. Inhibition of FoxO1 suppressed autophagy flux and almost completely prevented adipocyte differentiation. For the first time, we found that the kinetics of FoxO1 activation followed a series of sigmoid curves that showed multiple activation-inactivation transitions during adipogenesis. Our study provides critical evidence casting light on the controversy in the literature that either persistent inhibition or activation of FoxO1 suppresses adipogenesis. In addition, we identified two central pathways that FoxO1-mediated autophagy regulated adipocyte biology: (1) to control lipid droplet growth via fat specific protein 27 (FSP27) in adipocytes; and (2) to differentially regulate mitochondrial uncoupling proteins (UCP) that have been implicated in browning of white adipose tissue and redox homeostasis. Mechanistically, FoxO1 appears to induce autophagy through the transcription factor EB (Tfeb), which was previously shown to regulate both autophagosome and lysosome. Chromatin immunoprecipitation assay demonstrated that FoxO1 directly bound to the promoter of Tfeb, and inhibition of FoxO1 attenuated the binding, which resulted in reduced Tfeb expression. To investigate the role of FoxO1 in vivo, we have developed mouse models to modulate FoxO1 in adipose tissue using an inducible Cre-loxP system. Tamoxifen is widely used to activate the inducible Cre recombinase that spatiotemporally control target gene expression in animal models, but it was unclear whether tamoxifen itself may affect adiposity and confounds phenotyping. Part of my dissertation work was to address this important question. We found that tamoxifen led to reduced fat mass independent of Cre, which lasted for 4-5 weeks. Mechanistically, Tamoxifen induced reactive oxygen species (ROS) and augmented apoptosis. Our data reveals a critical period of recovery following tamoxifen treatment in the study of inducible knockout mice. Together, my dissertation work demonstrates FoxO1 as a critical regulator of adipocyte autophagy via Tfeb during adipogenesis. FoxO1-mediated autophagy controls FSP27, lipid droplet growth, and mitochondrial uncoupling proteins. Further study of FoxO1-autophagy axis in obese subjects is of physiological significance, and the investigation is under way.
Impact of Individual and Worksite Environmental Factors on Water and Sugar-Sweetened Beverage Consumption Among Overweight Employees
Davy, Brenda M.; You, Wen; Almeida, Fabio A.; Wall, Sarah; Harden, Samantha M.; Comber, Dana L.; Eatabrooks, Paul A. (Centers for Disease Control and Prevention, 2014-05-01)
Introduction The worksite environment may influence employees’ dietary behaviors. Consumption of water and sugar-sweetened beverages (SSBs) affect weight management; however, little research has evaluated the influence of worksite factors on beverage consumption. Our purpose was to determine whether individual and worksite factors are associated with water and SSB intake among overweight and obese employees. Methods Data were collected as part of baseline assessments for a worksite-based, weight-management intervention trial. Height and weight of participants (N = 1,482; 74% female; mean age = 47 y [standard deviation (SD) = 11y]; mean weight = 208 lbs [SD = 46 lbs]) were assessed, and participants completed a validated beverage intake questionnaire. Environmental characteristics of worksites (N = 28) were audited. A qualitative comparative analysis (QCA) was used to identify worksite conditions that may support healthier beverage intake patterns. Results Most participants were white (75% of sample) with at least some college education or a college degree (approximately 82% of sample). Mean water and SSB intake were 27 fl oz (SD = 18 fl oz) and 17 fl oz (SD = 18 fl oz), respectively; SSB intake (191 kcal [SD = 218 kcal]) exceeded the recommended discretionary energy intake. Statistical models did not identify any significant predictors of water intake. Female sex and increasing level of education and household income were associated with lower SSB intake; baseline body weight and greater number of worksite water coolers and vending machines were associated with higher SSB intake. The QCA identified worksite type (ie, not manual labor) as a condition necessary for healthier beverage consumption; a worksite break policy of 2 or more per day may lead to unhealthy beverage consumption. Lower SSB consumption was noted among older participants, female participants, and among participants with higher education and income levels. Conclusion Workplace factors influence beverage consumption among overweight employees. Limiting vending machine availability and implementing policies that promote weight management may improve employee health.
Insulin resistance is associated with epigenetic and genetic regulation of mitochondrial DNA in obese humans
Zheng, Louise D.; Linarelli, Leah E.; Liu, Longhua; Wall, Sarah S.; Greenawald, Mark H.; Seidel, Richard W.; Estabrooks, Paul A.; Almeida, Fabio A.; Cheng, Zhiyong (2015-06-10)
Background Mitochondrial alterations have been observed in subjects with metabolic disorders such as obesity and diabetes. Studies on animal models and cell cultures suggest aberrant glucose and lipid levels, and impaired insulin signaling might lead to mitochondrial changes. However, the molecular mechanism underlying mitochondrial aberrance remains largely unexplored in human subjects. Results Here we show that the mitochondrial DNA copy number (mtDNAn) was significantly reduced (6.9-fold lower, p < 0.001) in the leukocytes from obese humans (BMI >30). The reduction of mtDNAn was strongly associated with insulin resistance (HOMA-IR: −0.703, p < 0.05; fasting insulin level: −0.015, p < 0.05); by contrast, the correlation between fasting glucose or lipid levels and mtDNAn was not significant. Epigenetic study of the displacement loop (D-loop) region of mitochondrial genome, which controls the replication and transcription of the mitochondrial DNA as well as organization of the mitochondrial nucleoid, revealed a dramatic increase of DNA methylation in obese (5.2-fold higher vs. lean subjects, p < 0.05) and insulin-resistant (4.6-fold higher vs. insulin-sensitive subjects, p < 0.05) individuals. Conclusions The reduction of mtDNAn in obese human subjects is associated with insulin resistance and may arise from increased D-loop methylation, suggesting an insulin signaling-epigenetic-genetic axis in mitochondrial regulation.
An Interactive Computer Session to Initiate Physical Activity in Sedentary Cardiac Patients: Randomized Controlled Trial
Almeida, Fabio A.; Smith-Ray, Renae L.; Dzewaltowski, David A.; Glasgow, Russell E.; Lee, Rebecca E.; Thomas, Deborah S. K.; Xu, Stanley; Estabrooks, Paul A. (2015-08)
Background: Physical activity (PA) improves many facets of health. Despite this, the majority of American adults are insufficiently active. Adults who visit a physician complaining of chest pain and related cardiovascular symptoms are often referred for further testing. However, when this testing does not reveal an underlying disease or pathology, patients typically receive no additional standard care services. A PA intervention delivered within the clinic setting may be an effective strategy for improving the health of this population at a time when they may be motivated to take preventive action. Objective: Our aim was to determine the effectiveness of a tailored, computer-based, interactive personal action planning session to initiate PA among a group of sedentary cardiac patients following exercise treadmill testing (ETT). Methods: This study was part of a larger 2x2 randomized controlled trial to determine the impact of environmental and social-cognitive intervention approaches on the initiation and maintenance of weekly PA for patients post ETT. Participants who were referred to an ETT center but had a negative-test (ie, stress tests results indicated no apparent cardiac issues) were randomized to one of four treatment arms: (1) increased environmental accessibility to PA resources via the provision of a free voucher to a fitness facility in close proximity to their home or workplace (ENV), (2) a tailored social cognitive intervention (SC) using a "5 As"-based (ask, advise, assess, assist, and arrange) personal action planning tool, (3) combined intervention of both ENV and SC approaches (COMBO), or (4) a matched contact nutrition control (CON). Each intervention was delivered using a computer-based interactive session. A general linear model for repeated measures was conducted with change in PA behavior from baseline to 1-month post interactive computer session as the primary outcome. Results: Sedentary participants (n=452; 34.7% participation rate) without a gym membership (mean age 58.57 years; 59% female, 78% white, 12% black, 11% Hispanic) completed a baseline assessment and an interactive computer session. PA increased across the study sample (F-1,F-441= 30.03, P<.001). However, a time by condition interaction (F-3,F-441= 8.33, P<. 001) followed by post hoc analyses indicated that SC participants exhibited a significant increase in weekly PA participation (mean 45.1, SD 10.2) compared to CON (mean -2.5, SD 10.8, P=.004) and ENV (mean 8.3, SD 8.1, P<. 05). Additionally, COMBO participants exhibited a significant increase in weekly PA participation (mean 53.4, SD 8.9) compared to CON (P<.001) and ENV (P=.003) participants. There were no significant differences between ENV and CON or between SC and COMBO. Conclusions: A brief, computer-based, interactive personal action planning session may be an effective tool to initiate PA within a health care setting, in particular as part of the ETT system.
Mitochondrial alteration in type 2 diabetes and obesity
Cheng, Zhiyong; Almeida, Fabio A. (Landes Bioscience, 2014-03-15)
The growing epidemic of type 2 diabetes mellitus (T2DM) and obesity is largely attributed to the current lifestyle of over-consumption and physical inactivity. As the primary platform controlling metabolic and energy homeostasis, mitochondria show aberrant changes in T2DM and obese subjects. While the underlying mechanism is under extensive investigation, epigenetic regulation is now emerging to play an important role in mitochondrial biogenesis, function, and dynamics. In line with lifestyle modifications preventing mitochondrial alterations and metabolic disorders, exercise has been shown to change DNA methylation of the promoter of PGC1α to favor gene expression responsible for mitochondrial biogenesis and function. In this article we discuss the epigenetic mechanism of mitochondrial alteration in T2DM and obesity, and the effects of lifestyle on epigenetic regulation. Future studies designed to further explore and integrate the epigenetic mechanisms with lifestyle modification may lead to interdisciplinary interventions and novel preventive options for mitochondrial alteration and metabolic disorders.
Mitochondrial Epigenetic Changes Link to Increased Diabetes Risk and Early-Stage Prediabetes Indicator
Zheng, Louise D.; Linarelli, Leah E.; Brooke, Joseph; Smith, Cayleen M.; Wall, Sarah S.; Greenawald, Mark H.; Seidel, Richard W.; Estabrooks, Paul A.; Almeida, Fabio A.; Cheng, Zhiyong (Hindawi, 2016-04-26)
Type 2 diabetes (T2D) is characterized by mitochondrial derangement and oxidative stress. With no known cure for T2D, it is critical to identify mitochondrial biomarkers for early diagnosis of prediabetes and disease prevention. Here we examined 87 participants on the diagnosis power of fasting glucose (FG) and hemoglobin A1c levels and investigated their interactions with mitochondrial DNA methylation. FG and A1c led to discordant diagnostic results irrespective of increased body mass index (BMI), underscoring the need of new biomarkers for prediabetes diagnosis. Mitochondrial DNA methylation levels were not correlated with late-stage (impaired FG or A1c) but significantly with early-stage (impaired insulin sensitivity) events. Quartiles of BMI suggested that mitochondrial DNA methylation increased drastically from Q1 (20 < BMI < 24.9, lean) to Q2 (30 < BMI < 34.9, obese), but marginally from Q2 to Q3 (35 < BMI < 39.9, severely obese) and from Q3 to Q4 (BMI > 40, morbidly obese). A significant change was also observed from Q1 to Q2 inHOMA insulin sensitivity but not in A1c or FG. Thus, mitochondrial epigenetic changes link to increased diabetes risk and the indicator of early-stage prediabetes. Further larger-scale studies to examine the potential of mitochondrial epigenetic marker in prediabetes diagnosis will be of critical importance for T2D prevention.
Physical activity promotion in Latin American populations: a systematic review on issues of internal and external validity
Galaviz, Karla I.; Harden, Samantha M.; Smith, Erin M.; Blackman, Kacie C. A.; Berrey, Leanna M.; Mama, Scherezade K.; Almeida, Fabio A.; Lee, Rebecca E.; Estabrooks, Paul A. (2014-06-17)
The purpose of this review was to determine the degree to which physical activity interventions for Latin American populations reported on internal and external validity factors using the RE-AIM framework (reach & representativeness, effectiveness, adoption, implementation, maintenance). We systematically identified English (PubMed; EbscoHost) and Spanish (SCIELO; Biblioteca Virtual en Salud) language studies published between 2001 and 2012 that tested physical activity, exercise, or fitness promotion interventions in Latin American populations. Cross-sectional/descriptive studies, conducted in Brazil or Spain, published in Portuguese, not including a physical activity/fitness/exercise outcome, and with one time point assessment were excluded. We reviewed 192 abstracts and identified 46 studies that met the eligibility criteria (34 in English, 12 in Spanish). A validated 21-item RE-AIM abstraction tool was used to determine the quality of reporting across studies (0-7 = low, 8-14 = moderate, and 15-21 = high). The number of indicators reported ranged from 3-14 (mean = 8.1 ± 2.6), with the majority of studies falling in the moderate quality reporting category. English and Spanish language articles did not differ on the number of indicators reported (8.1 vs. 8.3, respectively). However, Spanish articles reported more across reach indicators (62% vs. 43% of indicators), while English articles reported more across effectiveness indicators (69% vs 62%). Across RE-AIM dimensions, indicators for reach (48%), efficacy/effectiveness (67%), and implementation (41%) were reported more often than indicators of adoption (25%) and maintenance (10%). Few studies reported on the representativeness of participants, staff that delivered interventions, or the settings where interventions were adopted. Only 13% of the studies reported on quality of life and/or potential negative outcomes, 20% reported on intervention fidelity, and 11% on cost of implementation. Outcomes measured after six months of intervention, information on continued delivery and institutionalization of interventions, were also seldom reported. Regardless of language of publication, physical activity intervention research for Latin Americans should increase attention to and measurement of external validity and cost factors that are critical in the decision making process in practice settings and can increase the likelihood of translation into community or clinical practice.
Pragmatic Implementation Trials: Understanding the Integrated Research-Practice Partnership Approach to Lifestyle Obesity Management Across a Transforming Health System
Johnson, Sarah Elizabeth (Virginia Tech, 2017-01-10)
Obesity, a condition of excess body fat, is one of the most complex problems facing health systems. Lifestyle management programs that combine diet, physical activity, and intensive behavioral therapy have been shown by research to support a degree of weight loss that produces health benefits (i.e., at least a 3-5% initial body weight). However, it has been difficult for research-developed programs to be delivered in typical practice to have a meaningful impact. Integrated research-practice partnerships that involve the coming together of academic researchers, health system administrators, and program delivery staff may help overcome this gap, especially during this transformational time in the healthcare sector. This dissertation aimed to develop an understanding of how using the integrated research-practice approach would facilitate and sustain evidence-based lifestyle management strategies across a health system to treat obesity among patients and employees. An integrated research-practice partnership with Carilion Clinic, a health system in western Virginia, served as an example for the study. From 2013-2016, the Carilion Clinic integrated research-practice partnership conducted a series of trials testing different strategies for delivering weight loss and weight loss maintenance support. An evaluation guided by the RE-AIM (Reach, Effectiveness, Adoption, Implementation, and Maintenance) framework was conducted to describe implementation processes and outcomes for each strategy. Lessons learned from the evaluation support the value of the integrated-research practice partnership approach as a solution for overcoming gaps in obesity care. A shared priority perspective between research and practice was identified as the powerful process for supporting facilitation and sustainability of strategies. In addition, findings from the evaluation produced evidence to inform the future development of a system for Carilion Clinic to help patients and employees lose weight and keep it off through lifestyle management.
Temporal examination of DNA methylation profile reprogramming in the promoter region of PGC-1α during the progression of insulin resistance and type 2 diabetes mellitus in rodent models
Donnelly, Sarah Rebecca (Virginia Tech, 2019-07-31)
Type 2 Diabetes Mellitus (T2DM), a metabolic disorder denoted by elevated blood glucose levels and insufficient insulin action, is growing in prevalence worldwide . Barriers to improving disease outcome resolve primarily around identifying and intervening during the preliminary stages of insulin resistance, a state clinically referred to as pre-diabetes. Emerging evidence suggests that mitochondrial dysfunction may underlie , and potentially precede, progressive insulin resistance, suggesting that biomarkers indicative of mitochondrial dysfunction could predict disease risk and status. In this study, we examined epigenetic modifications, in the form of DNA methylation, in the promoter region of peroxisome proliferator activated receptor gamma coactivator 1 alpha (PGC-1α), a known regulator of mitochondrial biogenesis. Following the initiation of a high fat diet, we observed significant genotypic (DNA methylation) and phenotypic (mitochondrial copy number) alterations in C57/BL6 rodent models. These changes preceded overt disease onset, as classified by clinically utilized indices, which included the homeostatic model assessment for insulin resistance (HOMA-IR), the homeostatic model assessment for β-cell dysfunction (HOMA- β), and the quantitative insulin-sensitivity check index (QUICKI). Our data indicate that methylation analysis may serve as an effective clinical parameter to use in conjunction with physiological criterion for the diagnosis of pre-diabetes and the assessment of T2DM disease risk, and adds to the growing body of work seeking to elucidate the role.
Theory of Planned Behavior: Item Response Sets and Prediction of Physical Activity
Nault, Edith Madeline (Virginia Tech, 2013-09-04)
Background: Less than half of Americans meet the recommendation of leisure-time physical activity (PA) of 150 minutes (CDC, 2012). A number of efficacious programs have been developed, and those that are based on theory are more effective. However, it is often difficult to determine the mechanisms of effect through meditational analyses. This is particularly an issue when a theory-based intervention is effective but theoretically hypothesized meditational relationships are not found. One reason for the lack of relationship could be the methods used to assess different theoretical constructs. The Theory of Planned Behavior (TPB) is one model used in the exercise and PA research domain which generally employs traditional fixed-graded measures of proposed theoretical mediators (e.g., strongly disagree to strongly agree response sets). More recent research provides initial evidence that using continuous-open scaling (e.g., ratio-level scaling; days or time/per week rather than agreement scales) has shown the superiority in measurement accuracy demonstrated by stronger relationships between the theoretical constructs and behavioral outcomes when compared to other scaling types. However, continuous open scaling has only been applied to correlational studies and there is no evidence that this scaling procedure results in measures that are sensitive to change or are related to both self-reported and objectively measured PA. Primary Aims: The primary aims of this study were to determine 1) the sensitivity to change of TPB constructs using different response sets and self-report and accelerometer assessed PA, and 2) if TPB constructs measured using the different response-sets have differential prediction of PA measured using self-report and accelerometry. Methods: Forty-six young adults were recruited to complete 13-item measure of TPB constructs using both fixed-graded and continuous-open scales as well as Godin's Leisure Time Exercise Questionnaire at 3 time (T1=Baseline, T2=End of week 1, T3=End of week 2) points over 2-weeks. Potential participants were excluded if they engaged in PA of 150 minutes or more per week. Inclusion criteria were the ability to perform moderate intensity PA and aged 18-25 years old. The order of different scales for the TPB constructs was randomly and evenly assigned within each condition. Participants were asked to wear an accelerometer for 2 weeks; one week prior to the action planning activity and one week after. To determine the sensitivity to change of the measures, participants were randomly assigned to either complete a personal action plan for physical activity (AP) or not (Control). Due to the exploratory nature of the pilot we set the significance level for all tests at p<0.10. Results: In general responses to the continuous open versus fixed closed items, at each time point, resulted in significantly (p<.05) lower perceptions of attitude (instrumental attitudes T1=4.4, T2=4.2, T3=4.3 versus time1= 6.2, T2=6.4, T3=6.3; affective attitudes T1=3.6, T2=3.5, T3=3.9 versus time1= 5.0, T2=5.0, T3=4.8), subjective norm ( T1=3.4, T2=3.3, T3=2.4 versus time1= 5.3, T2=5.2, T3=5.3), perceptions of control ( T1=3.2, T2=3.7, T3=3.9 versus time1= 4.6 T2=4.9, T3=5.2), and intention (T1=1.5, T2=1.8, T3=2.4 versus time1= 4.8, T2=5.1, T3=5.2). In regards to sensitivity to change continuous open and fixed closed measures of instrumental attitudes, subjective norms did not demonstrate significant changes as a result of action planning. Affective attitudes measured by the continuous-open scale, but not when measured by the fixed-closed scale, showed change over time regardless of condition. Perceived behavioral control measured using the continuous-open scale increased for AP participants by approximately 0.5 compared to control participants change of approximately 0.1 (p=.09). A similar pattern was found with intention in that changes in the continuous-open scale were significant (AP=0.9; control=0.2; p=0.07). No other scales showed significant sensitivity to change. Self-reported PA increased significantly for AP participants (81-16 minutes per week of PA) when compared to control participants (87 +/- 19 to 75 +/- 17 minutes per week of PA; p<0.1). Same pattern of differences was shown between AP (65 +/- 13 to 107 +/- 15 minutes per week of PA) and control (70 +/- 14 to 65 +/- 16 minutes per week of PA) participants (p<0.05). Conclusions: Continuous open scaling have significant correlations with all constructs along with affective attitude and intention being correlated with the actual reported exercise behavior over fixed graded scaling. This data sheds further insight into the different response sets of the TPB in application to exercise domain within a sedentary, young population. The lack of a significant difference may be due to the small sample size. Further research should investigate the role of the personalized action plan utilizing a larger sample size and the correlation of the TPB with intention and actual exercise behavior within an intervention.
Who Participates in Internet-Based Worksite Weight Loss Programs?
You, Wen; Almeida, Fabio A.; Zoellner, Jamie M.; Hill, Jennie L.; Pinard, Courtney A.; Allen, Kacie C.; Glasgow, Russell E.; Linnan, Laura A.; Estabrooks, Paul A. (2011-09-20)
Background The reach and representativeness are seldom examined in worksite weight loss studies. This paper describes and illustrates a method for directly assessing the reach and representativeness of a internet-based worksite weight loss program. Methods A brief health survey (BHS) was administered, between January 2008 and November 2009, to employees at 19 worksites in Southwest Virginia. The BHS included demographic, behavioral, and health questions. All employees were blinded to the existence of a future weight loss program until the completion of the BHS. Results The BHS has a participation rate of 66 percent and the subsequent weight loss program has a participation rate of 30 percent. Employees from higher income households, with higher education levels and health literacy proficiency were significantly more likely to participate in the program (p's < .01). Conclusions Worksite weight loss programs should include targeted marketing strategies to engage employees with lower income, education, and health literacy.

Browsing by Author "Almeida, Fabio A."

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