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Scholarly Works (12 results)

  • Thesis
  • Peer Reviewed
UC San Diego Electronic Theses and Dissertations (2022)

Celiac disease is a chronic illness in which quality of life (QOL) is compromised and psychiatric illness is commonly co-occurring. The only available treatment for celiac disease is to consume a gluten-free diet indefinitely, which is burdensome and costly. Further, adults with celiac disease present with a variety of gastrointestinal and extraintestinal symptoms that can persist after diagnosis and may relate differently to gluten-free diet adherence, psychiatric wellbeing, and QOL. Despite a need for behavioral intervention to address these challenges, adults with celiac disease are understudied. This three-paper dissertation addressed gaps in the literature by (1) examining the factor structure and psychometric properties (internal reliability, convergent validity, known groups validity, incremental concurrent validity) of Celiac Disease Quality of Life Survey (CD-QOL) scores among U.S. adults with celiac disease; (2) examining patterns of persisting physical symptoms and their respective relationships to gluten-free diet adherence, psychiatric symptoms, and QOL using latent profile analysis; and (3) systematically reviewing the design of single-session Acceptance and Commitment Therapy (ACT) interventions for chronic illness populations and meta-analyzing QOL and functioning outcomes to inform future behavioral intervention development for celiac disease. Studies 1 and 2 used U.S. adult participant data from the iCureCeliac® patient-powered research network. Study 1 (N=453) results supported use of the 20-item English CD-QOL as a measure of celiac disease-specific QOL with a total score and four subscale scores (limitations, dysphoria/stigma, health concerns, and inadequate treatment). Study 2 (N=523) identified four unique physical symptom profiles characterized by variations in gastrointestinal and extraintestinal symptoms and subjective ratings of health. Subgroups associated with these profiles also differed regarding anxiety and depression symptoms, limitations due to physical and emotional health, social functioning, and fatigue/sleep, but not gluten-free adherence or celiac-disease specific QOL. Study 3 found support for the acceptability, feasibility, and preliminary efficacy of single-session ACT for improving QOL and psychiatric symptoms among chronic illness populations. Findings suggest that healthcare providers should screen for psychiatric symptoms and QOL deficits among adult celiac disease patients regardless of symptom burden, and development of brief ACT for celiac disease is warranted. Findings must be replicated in culturally diverse samples.

    Cover page: Quality of Life among Patients with Celiac Disease: Assessment and Treatment in an Understudied Population
    • Article
    • Peer Reviewed
    UC San Diego Previously Published Works (2023)

    Purpose

    Celiac disease and its treatment negatively impact quality of life, indicating potential need for measurement of disease-specific quality of life domains to inform interdisciplinary intervention. The Celiac Disease Quality of Life Survey (CD-QOL) has been used in clinical research; however, its factor structure has not been confirmed and psychometric properties have not been evaluated in English-speaking adults in the U.S.

    Aims

    (1) Confirm the factor structure of the 20-item English CD-QOL; (2) assess psychometric properties including internal consistency reliability, convergent validity, known groups validity, and incremental validity.

    Methods

    453 adults with self-reported Celiac disease (Mage = 40.57; 88% female; 92% White) completed the CD-QOL and validated measures of generic health-related quality of life (SF-36), gluten-free diet adherence (CDAT), anxiety and depression symptoms (PROMIS), and physical symptoms (CSI) as part of the iCureCeliac® patient-powered research network.

    Results

    Confirmatory factor analysis found superior fit for a bifactor structure with one general factor and four group factors. Ancillary bifactor analyses suggest the CD-QOL can be considered primarily unidimensional. Total and three subscale scores demonstrated acceptable internal consistency reliability. Convergent and known groups validity were supported. The CD-QOL demonstrated some incremental validity over the SF-36.

    Conclusion

    The English CD-QOL can be used as a measure of disease-specific quality of life among adults with Celiac disease in the U.S. Compared to generic instruments, the CD-QOL appears to better capture specific cognitive and affective aspects of living with Celiac disease. Use of a total score is recommended. Its utility as a screening and outcome measurement tool in clinical settings should be examined.
      Cover page: Psychometric validation of the celiac disease-specific quality of life survey (CD-QOL) in adults with celiac disease in the United States
      • Article
      • Peer Reviewed
      UC San Diego Previously Published Works (2021)
      Obesity, binge-eating symptoms, and PTSD symptoms commonly co-occur. Avoidance, a key feature of PTSD and proposed mechanism of binge-eating, is one potential mechanism for explaining this clinical overlap. The purpose of the current study was to: 1) examine the associations between PTSD symptoms (PTSD Checklist-Civilian; PCL-C) and measures of bingeeating symptoms (Binge Eating Scale; BES) and obesity-related quality of life (Obesity Related Well-Being Questionnaire-97; ORWELL-97) in a sample of veterans with overweight or obesity (N = 89), and 2) determine whether experiential avoidance (The Acceptance and Action Questionnaire-II; AAQ-II) explains the relationship between PTSD symptoms and binge-eating symptoms, and PTSD symptoms and obesity-related quality of life, respectively. Scores on the PCL-C, BES, ORWELL-97, and AAQ-II were all significantly correlated. Linear regression analyses indicated that higher PCL-C scores were related to higher scores on the BES and ORWELL-97 after controlling for potentially confounding factors (BMI and race). Effect sizes were in the medium-large range. Further, AAQ-II mediated the relationship between PCL-C and ORWELL-97, but did not mediate the relationship between PCL-C and BES. These findings suggest that experiential avoidance should be considered in interventions addressing co-occurring PTSD, binge-eating, and poor obesity-related well-being. Longitudinal research is needed to better understand directionality of these relationships and changes over time.
        Cover page: Understanding relationships between posttraumatic stress disorder symptoms, binge-eating symptoms, and obesity-related quality of life: the role of experiential avoidance
        • Article
        • Peer Reviewed
        UC San Diego Previously Published Works (2019)
        Ability to restrain one's dietary intake is a necessary skill for weight loss. However, dietary restraint has been shown to paradoxically increase disinhibited eating in certain populations, thereby negatively impacting weight loss and leading to worse overall health outcomes. The aim of this study was to address gaps in the literature regarding the relationships between separate facets of dietary restraint (intention; behavior) with weight loss and various types of disinhibited eating (binge eating, external eating, emotional eating) in overweight and obese adults who recently completed a weight loss intervention. A sample of mostly male Veterans with overweight and obesity (N = 88) self-reported their dietary restraint intention, restraint behavior, and current disinhibited eating following completion of an 8-week behavioral weight loss treatment. Greater dietary restraint intention was related to greater dietary restraint behavior, p < .05. Greater dietary restraint behavior was significantly related to greater recent weight loss, p < .05, while restraint intention was not, p > .05. Greater dietary restraint intention was related to greater current binge eating and external eating, while greater self-reported restraint behavior was related to less binge eating, p < .05. Thus, dietary restraint behavior appears to be adaptive for this population, whereas rigid dietary restraint intention may increase risk for disinhibited eating. To decrease disinhibited eating and improve weight loss outcomes in Veterans, interventions might specifically address rigid rule-following associated with abandonment of weight loss goals and help Veterans develop specific yet flexible eating plans. Future research should examine whether dietary restraint intention and behavior differentially predict disinhibited eating and weight loss outcomes prospectively.
          Cover page: Dietary restraint and weight loss in relation to disinhibited eating in obese Veterans following a behavioral weight loss intervention
          • Article
          • Peer Reviewed
          UC San Diego Previously Published Works (2021)

          Rationale

          Chronic health conditions (CHCs) are costly and difficult to manage. Patients often struggle with behavioral adherence to complex treatment regimens and experience psychiatric distress. Acceptance and Commitment Therapy (ACT) is a transdiagnostic behavioral approach that aims to improve functioning and quality of life (QoL), which are important treatment outcomes for this population. Preliminary efficacy of multi-session ACT in patients with CHCs has been demonstrated, and single-session ACT interventions have since been developed to increase feasibility, acceptability, and accessibility. The purpose of this systematic review and meta-analysis was to describe the literature on single-session ACT intervention studies in CHC populations with regards to (1) study design and methodology, (2) patient characteristics and conditions targeted, and (3) efficacy for outcomes across various domains, using narrative and quantitative methods.

          Methods

          PsycINFO, PubMed, and Web of Science were systematically searched in August 2020. Studies of single-session ACT interventions in adult patients with CHCs that reported quantitative outcomes in any of the following domains were included: (a) functioning and related domains (e.g., disability, QoL, well-being); (b) mental health; (c) physical health; (d) ACT processes. Both controlled and uncontrolled studies were included. Study quality was assessed using the Psychotherapy Outcome Study Methodology Rating Scale (POMRF). Between-group random effects meta-analysis was conducted on general functioning outcomes.

          Results

          Fourteen manuscripts reporting outcomes from 13 studies (N = 793) met inclusion criteria. Ten studies were identified by their authors as pilot or feasibility trials. Eight studies used comparison or control groups. Twelve studies delivered the ACT content in workshop format. Studies recruited for a variety of conditions. Narrative review found that between- and within-group effect sizes showed generally positive results favoring single-session ACT overall (69%), especially for measures of functioning and related domains (88%), mental health (67%), and ACT processes (73%). Meta-analysis found that ACT did not significantly outperform comparison groups on measures of general functioning (Hedges' g: -0.51, 95% confidence interval: [-1.19, 0.16]; I 2 = 86%; K = 5) despite a medium-sized pooled effect.

          Discussion

          Use of single-session ACT interventions in CHC populations is an emergent field. There is preliminary evidence for the acceptability, feasibility, and efficacy of these interventions, which provides support for further testing in fully-powered RCTs. Additional RCTs will enable larger meta-analyses and stronger conclusions about efficacy. Recommendations for future trials are provided.
            Cover page: Single-session acceptance and commitment therapy (ACT) interventions for patients with chronic health conditions: A systematic review and meta-analysis
            • Article
            • Peer Reviewed
            UC San Diego Previously Published Works (2022)
            Acceptance and Commitment Therapy (ACT) is a third-wave cognitive-behavioral treatment that targets psychological flexibility (PF), or the ability to persist in behavior consistent with values regardless of unwanted private experiences. The growing use of ACT necessitates an accurate assessment of PF. The Comprehensive Assessment of Acceptance and Commitment Therapy (CompACT) is a three-factor measure of PF (Openness to Experience, Valued Action, and Behavioral Awareness) whose psychometric properties have been examined in limited populations. The current study examined the factor structure and psychometric properties of the CompACT in U.S. military personnel who enrolled in a weight management randomized controlled trial. Military personnel who either failed or were at risk of failing the Navy's physical fitness assessment or had overweight/obese body mass index (BMI; N = 178, Mage = 29.15 years; MBMI = 33.13 kg/m2; 61.8% female) completed the CompACT and other questionnaires. Confirmatory factor analysis was used to evaluate the three-factor structure of the original 23-item CompACT (CompACT-23) as well as an 18-item version identified in a Portuguese sample (CompACT-18). Internal consistency and convergent validity with measures of weight-related experiential avoidance, perceived stress, anxiety, depression, PTSD symptoms, and life satisfaction were examined. The three-factor structure of the CompACT-23 showed poor fit to the data while the fit of the CompACT-18 was acceptable, as indicated by three descriptive indices (χ2/df = 1.73, RMSEA = 0.069, SRMR = 0.074). All descriptive fit indices in addition to two comparative fit indices (AIC and BIC) indicated improved model fit over the CompACT-23. The CompACT-18 and its subscales exhibited adequate internal consistency (α = 0.768 to 0.861) and convergent validity in expected directions with measures of weight-related experiential avoidance, perceived stress, anxiety, depression, PTSD symptoms, and satisfaction with life. Results support using the refined, English language CompACT-18 as a three-factor measure of PF in populations such as U.S. military personnel who may benefit from weight management intervention. Future research should explore the content validity of the full measure and the removed items. Lost content could mean the CompACT-23 and the CompACT-18 differentially assess PF. Additional studies should examine psychometric properties in large and more diverse samples to further evaluate the appropriateness of the measure across populations. Longitudinal studies are needed to examine test-retest reliability and sensitivity to change.
              Cover page: Confirmatory factor analysis of the Comprehensive Assessment of acceptance and Commitment Therapy (CompACT) in active-duty military personnel
              • Article
              • Peer Reviewed
              UC San Diego Previously Published Works (2021)
              Posttraumatic stress disorder (PTSD) and eating disorders (ED) frequently co-occur, but the mechanisms underlying this association remain unclear. EDs are characterized by features of maladaptive eating behaviors including disinhibited eating and cognitive dietary restraint. Identifying the genetic overlap between PTSD symptoms and maladaptive eating behaviors may elucidate biological mechanisms and potential treatment targets. A community sample of 400 same-sex twins (102 monozygotic and 98 dizygotic pairs) completed the PTSD Checklist-Civilian (PCL-C) for PTSD symptoms and the Three-Factor Eating Questionnaire-Reduced (TFEQ-R18) for eating behaviors (uncontrolled eating, emotional eating, and cognitive dietary restraint). We used biometric modeling to examine the genetic and environmental relationships between PCL-C and TFEQ-R18 total and subscales scores. Heritability was estimated at 48% for PTSD symptoms and 45% for eating behavior overall. Bivariate models revealed a significant genetic correlation between PTSD symptoms and eating behavior overall (rg =.34; CI:.07,.58) and Uncontrolled Eating (rg =.53; CI:.24,.84), and a significant environmental correlation between PTSD symptoms and Emotional Eating (re =.30; CI:.12,.45). These findings suggest the influence of common etiology. Future research and clinical efforts should focus on developing integrated treatments.
                Cover page: Genetic and environmental influences on posttraumatic stress disorder symptoms and disinhibited eating behaviors.
                • Article
                • Peer Reviewed
                UC San Diego Previously Published Works (2024)

                Background

                A subgroup of adults with celiac disease experience persistent gastrointestinal and extraintestinal symptoms, which vary between individuals and the cause(s) for which are often unclear.

                Methods

                The present observational study sought to elucidate patterns of persistent symptoms and the relationship between those patterns and gluten-free diet adherence, psychiatric symptoms, and various aspects of quality of life (QOL) in an online sample of adults with celiac disease. U.S. adults with self-reported, biopsy-confirmed celiac disease (N = 523; Mage = 40.3 years; 88% women; 93.5% White) voluntarily completed questionnaires as part of the iCureCeliac® research network: (a) Celiac Symptoms Index (CSI) for physical symptoms and subjective health; (b) Celiac Dietary Adherence Test for gluten-free diet adherence; (c) PROMIS-29, SF-36, and Celiac Disease Quality of Life Survey for psychiatric symptoms and QOL. Symptom profiles were derived using latent profile analysis and profile differences were examined using auxiliary analyses.

                Results

                Latent profile analysis of CSI items determined a four-profile solution fit best. Profiles were characterized by: (1) little to no symptoms and excellent subjective health (37% of sample); (2) infrequent symptoms and good subjective health (33%); (3) occasional symptoms and fair to poor subjective health (24%); (4) frequent to constant symptoms and fair to poor subjective health (6%). Profiles 2 and 3 reported moderate overall symptomology though Profile 2 reported relatively greater extraintestinal symptoms and Profile 3 reported relatively greater gastrointestinal symptoms, physical pain, and worse subjective health. Profiles differed on anxiety and depression symptoms, limitations due to physical and emotional health, social functioning, and sleep, but not clinical characteristics, gluten-free diet adherence, or QOL. Despite Profile 3's moderate symptom burden and low subjective health as reported on the CSI, Profile 3 reported the lowest psychiatric symptoms and highest quality of life on standardized measures.

                Conclusions

                Adults with celiac disease reported variable patterns of persistent symptoms, symptom severity, and subjective health. Lack of profile differences in gluten-free diet adherence suggests that adjunctive dietary or medical assessment and intervention may be warranted. Lower persistent symptom burden did not necessarily translate to better mental health and QOL, suggesting that behavioral intervention may be helpful even for those with lower celiac symptom burden.
                  Cover page: Celiac disease symptom profiles and their relationship to gluten-free diet adherence, mental health, and quality of life
                  • Article
                  • Peer Reviewed
                  UC San Diego Previously Published Works (2020)

                  Objective

                  To examine the psychometric properties of the English language version of the 10-item Acceptance and Action Questionnaire for Weight-Related Difficulties-Revised (AAQW-R) in a United States (U.S.) sample of women and men with overweight/obesity (OW/OB).

                  Method

                  Adults with OW/OB seeking weight loss (N = 283; 59% women) completed the AAQW-R and other weight-related and psychosocial measures. Confirmatory factor analysis was used to examine single-factor, three-factor, and second-order factor structures of the AAQW-R, which were previously examined in a sample of Portuguese women. A chi-square difference test was used to compare the fit of a single-factor structure with three-factor and second-order factor structures. Internal reliability and convergent validity were examined for the total and three-factor subscale scores.

                  Results

                  The single-factor structure evidenced poor fit to the data whereas the three-factor structure evidenced acceptable fit. The second-order structure was assessed qualitatively due to limitations to statistical model specification. The internal reliability of the AAQW-R total score and each of the three subscales were in the good and acceptable ranges, respectively. Total and subscale scores demonstrated good convergent validity.

                  Discussion

                  Findings suggest that the English language version of the AAQW-R can be used to assess weight-related experiential avoidance in U.S. adult samples with OW/OB as a three-factor construct (food as control, weight as a barrier to living, weight stigma), with or without a total score. Additional research should confirm measurement invariance among various sociodemographic groups.
                    Cover page: Confirmatory factor analysis of the Acceptance and Action Questionnaire for Weight-Related Difficulties-Revised (AAQW-R) in a United States sample of adults with overweight and obesity
                    • Article
                    • Peer Reviewed
                    UC San Diego Previously Published Works (2019)

                    Background

                    Poor functional exercise capacity is common among those with obesity; however, objective measures of exercise capacity are rarely examined in behavioral treatments targeting obese individuals. We examined whether a 4-week acceptance and commitment therapy (ACT) intervention for disinhibited eating or a behavioral weight loss (BWL) intervention improved exercise capacity and explored demographic and disinhibited eating variables related to exercise capacity.

                    Methods

                    Veterans (n = 61), randomized to receive ACT or BWL, completed an assessment of exercise capacity via the 6-min walk test (6MWT) at baseline and 6-month follow-up. Measures of disinhibited eating patterns and body mass index (BMI), at baseline and post-treatment, were also collected. Change in 6MWT distance and treatment group differences were examined using mixed ANOVAs. Characteristics related to baseline 6MWT and predictors of improvement in 6MWT at 6 months were examined with hierarchical multiple regression.

                    Results

                    There were overall significant improvements on the 6MWT from baseline to 6-month follow-up (F(1,59) = 11.14, p = .001, ηp2 = .159) but no differences between the ACT and BWL groups. Baseline BMI (β = - .33, p = .005) was the only variable related to baseline 6MWT. Improvements on the 6MWT were related to younger age (β = - .41, p = 0.001), female gender (β = .36, p = .001), and treatment-related increases in dietary restraint behaviors (β = .42, p = .001).

                    Conclusions

                    Functional exercise capacity improved among participants completing behavioral interventions for weight and disinhibited eating. Improvements in dietary behavior regulatory skills may have generalized to improved regulation in other behavioral domains associated with exercise capacity.
                      Cover page: Improvement in 6-min Walk Test Distance Following Treatment for Behavioral Weight Loss and Disinhibited Eating: an Exploratory Secondary Analysis
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