Committee:

Nancy W. Glynn (chair), EPIJason Fanning, Department of Health and Exercise Sciences, Wake Forest UniversityChaeryon Kang, Psychiatry, BiostatisticsBonny Rockette-Wagner, EPIChristopher E. Kline, Department of Health and Humna Development, School of EducationBarbara J. Nicklas, Department of Internal Medicine, Wake Forest University School of MedicineAbstract:

Greater perceived physical fatigability (herein fatigability), the susceptibility to physical fatigue anchored to specific tasks of quantifiable duration and intensity, is a deleterious and highly prevalent characteristic among older adults, preceding disability and death. Given robust associations with aerobic capacity and physical activity, fatigability may be modifiable through intervention; however, current literature lacks evidence in older adult populations and intervention components have not been well-described.

This dissertation used data from the Empowered with Movement to Prevent Weight Regain (EMPOWER) randomized trial to address key knowledge gaps. Highly fatigued (80% prevalence of more severe fatigability) older adults with obesity participated in one of three physical activity interventions in combination with weight loss: 1) aerobic exercise (n=60), 2) daylong movement (n=63), and 3) aerobic exercise and daylong movement (n=60). First, we examined the time  intervention interaction on two well-validated measures of fatigability to assess effectiveness of the different interventions. Next, we examined the mediation effects of three measures of aerobic capacity and two accelerometer-measured physical activity metrics on the association between the interventions and fatigability. Finally, we investigated the associations of fatigability with weight outcomes.

We found that fatigability measured using the Pittsburgh Fatigability Scale meaningfully improved during the intensive intervention period (6-month) and after a 12-month maintenance period. However, there were no significant time  intervention group differences in fatigability, suggesting the three interventions had similar benefits. Mediation analysis revealed improvements in fatigability may be partially attributed to lower cost-capacity ratio (a measure of effort during a slow task relative to peak effort) and higher moderate-vigorous physical activity. Finally, a clinically meaningful improvement in fatigability was associated with less weight regain during maintenance.

Collectively, our work establishes that fatigability can be modified by diverse physical activity interventions in combination with weight loss among older adults with obesity. Specifically, interventions that concomitantly target improving cost-capacity ratio and moderate-vigorous physical activity may provide the most benefit. Lowering fatigability may also be protective in preventing weight regain, although more research is indicated. Given the numerous age-related health consequences associated with greater fatigability, public health efforts to improve fatigability may promote healthy aging.

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The Spring 2026 theme is Alumni Career Spotlight.

Connect before and after the seminar:

Join us in the Commons for departmental networking from 11-11:30and in G23 for dialogue with faculty and speakers from 12:30-12:50 p.m.We encourage all to attend!

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Committee:

Anthony Fabio, (dissertation director), EPISonja A. Swanson, EPIJeanine M. Buchanich, BiostatisticsMarquis Hawkins, Department of PsychologyAmy L. Lavery, Geospatial Epidemiology and Applied Research unit lead, CDCAbstract:

Social vulnerability is widely recognized as a structural determinant of population health, yet commonly used national indices may inadequately capture within-region heterogeneity in historically disadvantaged areas such as Central Appalachia. This subregion is characterized by persistent economic distress, elevated disability burden, geographic isolation, and constrained health care access. Standard applications of the CDC/ATSDR Social Vulnerability Index (SVI) rely on nationally derived weighting and ranking approaches that may compress variability within uniformly high-risk regions, thereby limiting their utility for within-region discrimination. This dissertation develops and evaluates a regionally calibrated Central Appalachian Social Vulnerability Index (CASVI) designed to more accurately reflect structural conditions in Central Appalachia.
In Aim 1, we constructed the CASVI by re-weighting and re-ranking SVI component indicators within Central Appalachian counties. Driver-informed weighting strategies were applied to emphasize regional socioeconomic structure, disability prevalence, housing vulnerability, and markers of geographic isolation and access constraints. Rather than relying on national percentile rankings, counties were ranked within the Central Appalachian distribution to generate regionally meaningful quartiles of vulnerability. We examined shifts in county classification under CASVI relative to national SVI rankings to assess the extent to which national metrics masked heterogeneity across Central Appalachian counties.
In Aim 2, we evaluated construct and criterion validity of CASVI using external county-level indicators of structural disadvantage and population health, including all-cause mortality, years of potential life lost, overdose mortality, and broadband access. We compared the discriminatory performance of CASVI with the national SVI within Central Appalachia. The regionally calibrated index demonstrated improved differentiation of counties across multiple domains of structural vulnerability and stronger alignment with regionally salient indicators.
In Aim 3, we applied CASVI to examine county-level adult depression prevalence across 82 Central Appalachian counties as an illustrative population health outcome. Spatial regression models were used to account for geographic clustering and to assess vulnerability gradients within the region.
Collectively, this dissertation demonstrates that regionally calibrated vulnerability measurement improves contextual relevance and discriminatory performance within structurally disadvantaged regions. Findings support the development of place-specific indices to inform targeted public health policy, resource allocation, and intervention strategies in Central Appalachia.

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A reception will follow in the first floor commons until 2 p.m.

Named in honor of the late Kim Sutton-Tyrrell, a pioneering investigator, dedicated mentor, and faculty member. This event is part of seminar.

The Spring 2026 theme is Alumni Career Spotlight. Additional details for March and April seminars will be posted soon.

Connect before and after the seminar:

Join us in the Commons for departmental networking from 11-11:30and in G23 for dialogue with faculty and speakers from 12:30-12:50 p.m.We encourage all to attend!

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This year's speaker is Chris DeCardy, president, Heinz Endowments. Confirm your attendance today!

Working staff reporting at 12:30pm

Doors open to the public at 1:00pm

Faculty reporting at 1:30pm

Ceremony starting at 2:30pm

Parking will be available in the OC Lot and we will provide more information about parking and arriving for working staff, processing faculty and graduates, and guests. Contact Mike Dolinger with questions or see our 2024-25 event details in the meantime.

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