Adherence to the Physical Activity Goal among Adults with Overweight or Obesity in a mHealth Weight Loss Trial

Background: The use of wearable activity trackers can improve engagement in physical activity (PA). There is limited evidence on the long-term use of wearable activity trackers for promoting PA guidelines in adults with overweight or obesity. Objectives: This dissertation aimed to 1) identify baseline and short-term response predictors of adherence to the study-defined PA goal, 2) determine distinct trajectories of adherence to weekly PA goals and examine their association with baseline and first week response predictors and percent weight change at 12 months, and 3) explore associations between the percent of adherence to the PA goal and changes in percent body fat and sex-specific waist circumference (WC) in adults who are overweight or obese and participated in a mobile health (mHealth) weight loss intervention for 12 months. Methods: A secondary analysis was conducted of PA data collected using Fitbit Charge 2™ trackers from the SMARTER weight loss trial examining the efficacy of two interventions: self-monitoring of diet, PA and weight with daily tailored feedback (n=251) or self-monitoring alone (n=251). Results: The sample (N=502) was mostly female (80%), White (83%) with a mean age of 45±14.4 years and body mass index of 33.7±4.0 kg/m2. Machine learning methods identified higher PA goal adherence for the first week, greater PA intervention engagement, greater weight loss by the first month, older age, being male, and being not married/partnered as predictors of higher PA goal adherence over 52 weeks. Group-based trajectory modeling revealed 5 distinct trajectories of percent of adherence to weekly PA goals: extremely low adherence with linear decline (n=119, 23.7%), stable low adherence (n=161, 31.5%), initially adherent with cubic decline (n=114, 23%), adherent with cubic increase (n=79, 15.9%) and highly adherent with quadratic increase (n=29, 5.8%). Higher trajectories of adherence to weekly PA goals were associated with greater weight loss at 12 months. Lastly, greater PA goal adherence was associated with decreases in percent body fat and male WC. Conclusion: These findings have significant implications for public health given the high prevalence of obesity and sedentary behavior, and the comorbidities associated with these conditions that lead to rising healthcare costs and premature mortality

The role of leptin in cardiovascular outcomes in patients with type 2 diabetes: an analysis of he bypass angioplsty revascularization investigation 2 diabetes (BARI 2D) trial data

Background: Previous studies have reported that leptin increases the risk of atherogenesis and cardiovascular (CV) disease. However, the role that leptin plays in the development of atherosclerosis and the risk of CV events is complex in patients with type 2 diabetes. Objective: Evaluate the association between altered baseline leptin profiles and baseline atherosclerosis measurements in Bypass Angioplasty Revascularization Investigation Type 2 Diabetes (BARI 2D) patients with type 2 diabetes mellitus (T2DM) and determine if the association between baseline leptin and subsequent CV events was modified by the severity of baseline atherosclerosis. Methods: BARI 2D was a clinical trial with 2x2 factorial design that simultaneously randomized 2,368 participants with T2DM to prompt or delayed revascularization and to insulin sensitizing or insulin providing treatment. Atherosclerosis at baseline was quantified with the Myocardial Jeopardy Index (MJI). The cross-sectional associations between baseline leptin and MJI accounting for other demographic and clinical characteristics were tested using chi-square tests, Wilcoxon tests, and linear regression models. The effect of baseline leptin on subsequent CV events was assessed using Kaplan-Meier estimates, log rank tests and Cox proportional hazard regression models. Results: Patients with lower leptin levels had significantly higher baseline BMI, insulin and C-reactive protein levels. In multivariate linear regression models with the adjustment for demographics and clinical risk factors of CVD, each SD increase baseline leptin levels were significantly associated with the estimated 1.92% increase in MJI scores (β(se): 1.92 (0.67), p-value=0.004); however, upon inclusion of BMI, the association was attenuated β(se): 0.31 (0.77), p-value=0.69). Unadjusted Kaplan-Meier survival analyses indicated that the risk of MI was greatest for patients with low leptin levels (mortality rate=14%, p-value=0.06). The association between baseline and subsequent CV outcomes was not modified by severity of baseline atherosclerosis (MJI). Conclusion: Low leptin could serve as a clinical predictor of future MI among participants with T2DM, which may potentially lead to an intervention. This has public health significance when considering the large disease and economic burden of both T2DM and CVD morbidities in the United States

Reliability and Validity of Survey Instruments to Measure Work-Related Fatigue in the Emergency Medical Services Setting: A Systematic Review

<p><b>Background</b>: This study sought to systematically search the literature to identify reliable and valid survey instruments for fatigue measurement in the Emergency Medical Services (EMS) occupational setting. <b>Methods</b>: A systematic review study design was used and searched six databases, including one website. The research question guiding the search was developed a priori and registered with the PROSPERO database of systematic reviews: “Are there reliable and valid instruments for measuring fatigue among EMS personnel?” (2016:CRD42016040097). The primary outcome of interest was criterion-related validity. Important outcomes of interest included reliability (e.g., internal consistency), and indicators of sensitivity and specificity. Members of the research team independently screened records from the databases. Full-text articles were evaluated by adapting the Bolster and Rourke system for categorizing findings of systematic reviews, and the rated data abstracted from the body of literature as favorable, unfavorable, mixed/inconclusive, or no impact. The Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology was used to evaluate the quality of evidence. <b>Results</b>: The search strategy yielded 1,257 unique records. Thirty-four unique experimental and non-experimental studies were determined relevant following full-text review. Nineteen studies reported on the reliability and/or validity of ten different fatigue survey instruments. Eighteen different studies evaluated the reliability and/or validity of four different sleepiness survey instruments. None of the retained studies reported sensitivity or specificity. Evidence quality was rated as very low across all outcomes. <b>Conclusions</b>: In this systematic review, limited evidence of the reliability and validity of 14 different survey instruments to assess the fatigue and/or sleepiness status of EMS personnel and related shift worker groups was identified.</p

Shorter Versus Longer Shift Durations to Mitigate Fatigue and Fatigue-Related Risks in Emergency Medical Services Personnel and Related Shift Workers: A Systematic Review

<p><b>Background</b>: This study comprehensively reviewed the literature on the impact of shorter versus longer shifts on critical and important outcomes for Emergency Medical Services (EMS) personnel and related shift worker groups. <b>Methods</b>: Six databases (e.g., PubMed/MEDLINE) were searched, including one website. This search was guided by a research question developed by an expert panel <i>a priori</i> and registered with the PROSPERO database of systematic reviews (2016:CRD42016040099). The critical outcomes of interest were patient safety and personnel safety. The important outcomes of interest were personnel performance, acute fatigue, sleep and sleep quality, retention/turnover, long-term health, burnout/stress, and cost to system. Screeners worked independently and full-text articles were assessed for relevance. Data abstracted from the retained literature were categorized as favorable, unfavorable, mixed/inconclusive, or no impact toward the shorter shift duration. This research characterized the evidence as very low, low, moderate, or high quality according to the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology. <b>Results</b>: The searched yielded <i>n</i> = 21,674 records. Of the 480 full-text articles reviewed, 100 reported comparisons of outcomes of interest by shift duration. We identified 24 different shift duration comparisons, most commonly 8 hours versus 12 hours. No one study reported findings for all 9 outcomes. Two studies reported findings linked to both critical outcomes of patient and personnel safety, 34 reported findings for one of two critical outcomes, and 64 did not report findings for critical outcomes. Fifteen studies were grouped to compare shifts <24 hours versus shifts ≥24 hours. None of the findings for the critical outcomes of patient and personnel safety were categorized as unfavorable toward shorter duration shifts (<24 hours). Nine studies were favorable toward shifts <24 hours for at least one of the 7 important outcomes, while findings from one study were categorized as unfavorable. Evidence quality was low or very low. <b>Conclusions</b>: The quality of existing evidence on the impact of shift duration on fatigue and fatigue-related risks is low or very low. Despite these limitations, this systematic review suggests that for outcomes considered critical or important to EMS personnel, shifts <24 hours in duration are more favorable than shifts ≥24 hours.</p