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Open Access Publications from the University of California

Scholarly Works (16 results)

  • Thesis
  • Peer Reviewed
UC San Diego Electronic Theses and Dissertations (2016)

Background: This dissertation explored three hierarchical levels of the

Behavioral Ecological Model (BEM) related to childhood obesity by addressing the following aims: (1) explore the relationships between preadolescents’ body

composition (i.e., fat and lean mass) and bone mass/density; (2) explore the

relationships between preadolescents’ engagement in physical activity and sedentary behavior with their body composition; and (3) perform a systematic review evaluating the relationships between parental household rules, child/adolescent sleep, other obesity-related behaviors, and weight status/body composition.

Methods: For Aims 1 and 2, analysis of the validity baseline data collected

between 2009 and 2014 for the Healthy Smiles Trial was performed (N = 44). For Aim 3, a systematic review of the literature was performed using PubMed (Medline) and Google Scholar databases. After screening abstracts and articles for inclusion, studies included in the review (N = 48) were evaluated and study fidelity was scored.

Results: In 8- to 14-year-old boys and girls, DXA-derived body composition

was related to bone mass. Bivariate analyses showed lean mass measures were positively associated with total body less head (TBLH) and AP Spine (L1L4) bone mineral content (BMC)/density (BMD); however, after controlling for age, gender, height, weight, and pubertal status, the relationships were insignificant. Partial correlations controlling for age, gender, height, weight, and pubertal status showed fat mass index (FMI) was significantly negatively associated with TBLH BMC and L1L4 BMC (p < 0.01), and android fat mass was negatively associated with TBLH BMD (p < 0.05). In 8- to 14-year-old boys and girls, after controlling for age, gender, height, weight, leg length, and pubertal status, partial correlations showed moderate, vigorous, and MVPA were positively associated with DXA-derived lean mass measures and

negatively associated with DXA-derived fat mass measures (p < 0.05). There were no relationships between DXA-derived body composition and light PA, total PA, or sedentary time. Finally, systematic review results showed: (1) higher fidelity studies demonstrated expected relationships between parental household rules and associated obesity-related behaviors (e.g., TV watching rules associated with decreased TV time); (2) parental household rules demonstrated an inconsistent relationship with child weight status/body composition; (3) sleep duration was consistently inversely associated with child weight status, irrespective of study fidelity; (4) parental household rules may be related to sleep duration, and sleep duration may mediate the relationship between rules/child behaviors and child weight status, but more research

is needed. Several limitations in the literature were identified.

Conclusions: In summary, body composition is an important physiological

component and should be evaluated in addition to BMI, as lean and fat mass may have different yet important relationships with variables pertinent to childhood obesity related research. Both physical activity and sedentary behavior should continue to be concurrently evaluated, as they are not simply opposite ends of the same spectrum. Furthermore, future studies should confirm that intensity of PA may be more important with regard to child body composition and weight status, so more effective evidence based recommendations for preventing and reducing childhood obesity can be established. Finally, parental household rules may influence child obesity-related behaviors; however, more research is needed to determine their relationship with child weight status/body composition. Systematic review results call for more multi-level, dynamic, robust studies to determine more effectual means for combating childhood obesity.

    Cover page: Childhood Obesity Prevention: Is it a Hop, Jump, and a Skip Away? An Exploratory Study of the Behavioral Ecological Model and the Influence of Contingencies on Child Body Composition
    • Article
    • Peer Reviewed
    UC San Diego Previously Published Works (2019)
    PURPOSE: Cardiorespiratory fitness (CRF), broadly defined as the bodys ability to utilize oxygen, is a well-established prognostic marker of health, but it is not routinely measured. This may be due to the difficulty of acquiring high-quality CRF measures. The purpose of this study was to independently determine the validity of the Fitbit Charge 2s measure of CRF (Fitbit CRF). METHODS: Sixty-five healthy adults between the ages of 18 and 45 yr (55% female, 45% male) were recruited to undergo gold standard V˙O2max testing and wear a Fitbit Charge 2 continuously for 1 wk during which they were instructed to complete a qualifying outdoor run to derive the Fitbit CRF (units: mL·kg·min). This measure was compared with V˙O2max measures (units: mL·kg·min) epoched at 15 and 60 s. RESULTS: Bland-Altman analyses revealed that Fitbit CRF had a positive bias of 1.59 mL·kg·min compared with laboratory data epoched at 15 s and 0.30 mL·kg·min compared with data epoched at 60 s (n = 60). F statistics (2.09; 0.08) and P values (0.133; 0.926) from Bradley-Blackwood tests for the concordance of Fitbit CRF with 15- and 60-s laboratory data, respectively, support the null hypothesis of equal means and variances, indicating there is concordance between the two measures. Mean absolute percentage error was less than 10% for each comparison. CONCLUSIONS: The Fitbit Charge 2 provides an acceptable level of validity when measuring CRF in young, healthy, and fit adults who are able to run. Further research is required to determine if it is a potentially useful tool in clinical practice and epidemiological research to quantify, categorize, and longitudinally track risk for adverse outcomes.
      Cover page: Validity of Cardiorespiratory Fitness Measured with Fitbit Compared to V˙O2max.
      • Article
      • Peer Reviewed
      UC San Diego Previously Published Works (2023)
      Background: The median age of Americans is rising and fall risk increases with age. While the causes of falls are multifactorial, falls risk can be reduced. Only a small percentage of older-adults report being asked about fall risk or falls. The CDC has initiated a Stopping Elderly Accidents, Deaths and Injuries (STEADI) toolkit, but penetration into practice has been slow. To address this, we implemented a Falls Prevention Shared Medical Appointment (SMA) at an academic internal medicine clinic. Methods: Patients were referred to the SMA and scheduled per their preference virtually or in-person. Patients attended a nurse visit for appropriate fallrisk related screening, followed by the SMA with two physicians for review of medical history, fall screening results and implementation of fall reduction strategies. Follow-up survey of the patients assessed program effectiveness. Results: Fifty-two patients were seen/assessed between November 2021 and February 2023 with SMAs ranging from 3 to 5 patients with an average age of 77 (=/- 6.7). Questionnaire self-reported risk factors, self-reported strength, and polypharmacy were associated with objective markers of increased fall risk. Survey results indicate acceptability of this model. Conclusion: Falls prevention SMAs can be effective. More work is needed to further delineate and refine cohort selection.
        Cover page: Shared-Medical Appointment for Screening and Risk Assessment for Fall Prevention.
        • Article
        • Peer Reviewed
        UC San Diego Previously Published Works (2010)
        Breast cancer survivors not only experience distressing physical symptoms associated with treatments, but also are faced with psychosocial challenges. Despite growing scientific evidence that physical activity (PA) may mitigate psychosocial distress experienced by women treated for breast cancer, the literature is equivocal. This study investigated the relationships between cardiorespiratory fitness (CRF), PA, and psychosocial factors in breast cancer survivors. Data involving overweight or obese breast cancer survivors (N = 260) were examined. CRF was determined by a submaximal graded exercise test. PA, depressive symptoms, total fatigue, and global self-esteem were assessed with self-report measures. Pearson's correlations were conducted to determine associations among CRF, PA, depressive symptoms, total fatigue, and global self-esteem. Multiple regression models, with age and body mass index as covariates, were performed using continuous levels for CRF and PA. Bivariate correlations suggested that CRF and PA were unrelated to the psychosocial variables. One of the regression models identified a marginally significant (P = 0.06) inverse association between depressive symptoms and PA. CRF and PA were not associated with psychosocial factors in this sample of breast cancer survivors. However, minimal PA was reported by the majority of participants, so low PA variability likely influenced these findings.
          Cover page: Relationships Between Cardiorespiratory Fitness, Physical Activity, and Psychosocial Variables in Overweight and Obese Breast Cancer Survivors
          • Article
          • Peer Reviewed
          Publications (2018)
            • Article
            • Peer Reviewed
            UC San Diego Previously Published Works (2024)
            INTRODUCTION: While it is well recognised that aging is a heterogeneous process, our understanding of the determinants of biological aging and its heterogeneity remains unclear. The San Diego Nathan Shock Center (SD-NSC) Clinical Cohort aims to establish a resource of biospecimens and extensive donor clinical data such as physical, cognitive and sensory function to support other studies that aim to explore the heterogeneity of normal human aging and its biological underpinnings. METHODS AND ANALYSIS: The SD-NSC Clinical Cohort is composed of 80 individuals across the adult human lifespan. Strict inclusion and exclusion criteria are implemented to minimise extrinsic factors that may impede the study of normal aging. Across three visits, participants undergo extensive phenotyping for collection of physical performance, body composition, cognitive function, sensory ability, mental health and haematological data. During these visits, we also collected biospecimens including plasma, platelets, peripheral blood mononuclear cells and fibroblasts for banking and future studies on aging. ETHICS AND DISSEMINATION: Ethics approval from the UC San Diego School of Medicine Institutional Review Board (IRB #201 141 SHOCK Center Clinical Cohort, PI: Molina) was obtained on 11 November 2020. Written informed consent is obtained from all participants after objectives and procedures of the study have been fully explained. Congruent with the goal of establishing a core resource, biological samples and clinical data are made available to the research community through the SD-NSC.
              Cover page: Protocol for the San Diego Nathan Shock Center Clinical Cohort: a new resource for studies of human aging.Creative Commons 'BY-NC' version 4.0 license
              • Article
              • Peer Reviewed
              UC San Diego Previously Published Works (2015)

              Background

              Compliance with California's smoke-free restaurant and bar policies may be more a function of social contingencies and less a function of legal contingencies. The aims of this study were: 1) to report indications of compliance with smoke-free legislation in Korean bars and restaurants in California; 2) to examine the demographic, smoking status, and acculturation factors of who smoked indoors; and 3) to report social cues in opposition to smoking among a sample of Koreans in California.

              Materials and methods

              Data were collected by telephone surveys administered by bilingual interviewers between 2007-2009, and included California adults of Korean descent who visited a Korean bar or restaurant in a typical month (N=2,173, 55% female).

              Results

              1% of restaurant-going participants smoked inside while 7% observed someone else smoke inside a Korean restaurant. Some 23% of bar-going participants smoked inside and 65% observed someone else smoke inside a Korean bar. Presence of ashtrays was related to indoor smoking in bars and restaurants. Among participants who observed smoking, a higher percentage observed someone ask a smoker to stop (17.6%) or gesture to a smoker (27.0%) inside Korean restaurants (N=169) than inside Korean bars (n=141, 17.0% observed verbal cue and 22.7% observed gesture). Participants who smoked inside were significantly younger and more acculturated than participants who did not. Less acculturated participants were significantly more to likely to be told to stop smoking.

              Conclusions

              Ten years after implementation of ordinances, smoking appears to be common in Korean bars in California.
                Cover page: Compliance with Smoke-Free Policies in Korean Bars and Restaurants in California: a Descriptive Analysis
                • Article
                • Peer Reviewed
                UC San Diego Previously Published Works (2016)

                Background

                As wearable sensors/devices become increasingly popular to promote physical activity (PA), research is needed to examine how and which components of these devices people use to increase their PA levels.

                Aims

                (1) To assess usability and level of engagement with the Fitbit One and daily SMS-based prompts in a 6-week PA intervention, and (2) to examine whether use/ level of engagement with specific intervention components were associated with PA change.

                Methods

                Data were analyzed from a randomized controlled trial that compared (1) a wearable sensor/ device (Fitbit One) plus SMS-based PA prompts, and (2) Fitbit One only, among overweight/ obese adults (N = 67). We calculated average scores from Likert-type response items that assessed usability and level of engagement with device features (e.g., tracker, website, mobile app, and SMS-based prompts), and assessed whether such factors were associated with change in steps/day (using Actigraph GT3X+).

                Results

                Participants reported the Fitbit One was easy to use and the tracker helped to be more active. Those who used the Fitbit mobile app (36%) vs. those who did not (64%) had an increase in steps at 6-week follow-up, even after adjusting for previous web/app use: +545 steps/ day (SE = 265) vs. -28 steps/ day (SE = 242) (p = .04).

                Conclusions

                Level of engagement with the Fitbit One, particularly the mobile app, was associated with increased steps. Mobile apps can instantly display summaries of PA performance and could optimize self-regulation to activate change. More research is needed to determine whether such modalities might be cost-effective in future intervention research and practice.
                  Cover page: Mobile and Wearable Device Features that Matter in Promoting Physical Activity.
                  • Article
                  • Peer Reviewed
                  UC San Diego Previously Published Works (2024)
                  BACKGROUND: Aging results in changes in resting state functional connectivity within key networks associated with cognition. Cardiovascular function, physical activity, sleep, and body composition may influence these age-related changes in the brain. Better understanding these associations may help clarify mechanisms related to brain aging and guide interventional strategies to reduce these changes. METHODS: In a large (n = 398) sample of healthy community dwelling older adults that were part of a larger interventional trial, we conducted cross sectional analyses of baseline data to examine the relationships between several modifiable behaviors and resting state functional connectivity within networks associated with cognition and emotional regulation. Additionally, maximal aerobic capacity, physical activity, quality of sleep, and body composition were assessed. Associations were explored both through correlation and best vs. worst group comparisons. RESULTS: Greater cardiovascular fitness, but not larger quantity of daily physical activity, was associated with greater functional connectivity within the Default Mode (p = 0.008 r = 0.142) and Salience Networks (p = 0.005, r = 0.152). Better sleep (greater efficiency and fewer nighttime awakenings) was also associated with greater functional connectivity within multiple networks including the Default Mode, Executive Control, and Salience Networks. When the population was split into quartiles, the highest body fat group displayed higher functional connectivity in the Dorsal Attentional Network compared to the lowest body fat percentage (p = 0.011; 95% CI - 0.0172 to - 0.0023). CONCLUSION: These findings confirm and expand on previous work indicating that, in older adults, higher levels of cardiovascular fitness and better sleep quality, but not greater quantity of physical activity, total sleep time, or lower body fat percentage are associated with increased functional connectivity within key resting state networks.
                    Cover page: Cardiorespiratory Fitness and Sleep, but not Physical Activity, are Associated with Functional Connectivity in Older Adults.
                    • Article
                    • Peer Reviewed
                    UC San Diego Previously Published Works (2015)

                    Background

                    Depressive symptoms can lower adherence and change in dietary studies. Behavioral activation may reduce these effects.

                    Purpose

                    This study aims to assess relationships among depressive symptoms on adherence and dietary change in the Women's Healthy Eating and Living (WHEL) Study

                    Methods

                    Secondary analyses from the WHEL Study, which achieved major dietary change in breast cancer survivors (N = 2817), were conducted. Logistic regressions were undertaken of baseline depressive symptoms (six-item Center for Epidemiologic Studies Depression Scale (CES-D)) with (1) completion of 1- and 4-year study assessments and (2) validated change in dietary behavior in the intervention group.

                    Results

                    In the comparison group (vs. intervention), depressive symptoms lowered completion of dietary recalls and clinic visits [4 years: odds ratio (OR) = 2.0; 95 % confidence interval (CI) = 1.4-3.0]. The behaviorally oriented intervention achieved major change in those furthest from study targets, although changes were lower in those with depressive symptoms: fruit/vegetable (+37.2 %), fiber (+49.0 %), and fat (-22.4 %).

                    Conclusions

                    Behavioral activation in dietary change interventions can overcome the impact of depressive symptoms.
                      Cover page: Baseline Depressive Symptoms, Completion of Study Assessments, and Behavior Change in a Long-Term Dietary Intervention Among Breast Cancer Survivors
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