Examining the role of stressful life events on cognition and determining mediating and moderating pathways among postmenopausal women

BACKGROUND: Major life events, largely considered to be a source of great stress, are an inevitable process of the life span. Preliminary evidence suggests that the stress arising from major life events may serve as a risk factor for cognitive function decline. Evidence also indicates external (e.g., physical activity) and internal factors (i.e., psychological variables) can attenuate the physiologic effects of stress. Thus, there may be two important pathways through which stress affects health. PURPOSE: The primary aim of this dissertation was to investigate the independent and interactive effects of stressful life events on cognitive function among a sample of postmenopausal women. In addition, the possible moderating and or mediating role of external and internal factors on the relationship between stressful life events and cognitive function were examined. METHODS: Data from the Women's Health Initiative Memory Study, a randomly selected subset of the Women's Health Initiative Hormone Trial, were analyzed. To control for any treatment effects, only data from participants randomized into the placebo groups were pooled and used for all analyses, leaving a total of 3775participants. All participants had five data collections points, including baseline through four years of follow-up. Linear mixed effects models were used to answer all prospective research questions. Moderation and mediation models were used to determine presence of effect modification or mediation of external or internal variables. RESULTS: Our results appear to indicate that there was a negative relationship between stressful life events and cognitive function scores. Reporting an ill spouse/partner was associated with lower cognition scores compared to those without reporting a spouse/partner (B = -0.68, p < 0.0001). Exposure to three or more stressful life events at every data collection period was also associated with lower cognitive function scores (B = -0.61, p = 0.021). External factors did not appear to moderate this negative relationship; however, internal factors such as optimism, hostility, and negative expressiveness did. Specifically, exposure to more stressful life events was associated with less favorable psychological states, which in turn, were associated with lower cognitive function scores. CONCLUSION: Our results appear to lend support that exposure to certain life events and repeated exposure of stressful life events is associated with lower cognitive functioning. In addition, our findings provide modest evidence that psychological mechanisms are an important pathway through which stressful life events affect cognitive functioning over time among a representative sample of post-menopausal women. While stressful life events are largely unavoidable, the associated increased risk of cognitive function decline may be in part offset by various psychological factors

Prehabilitation Before Total Knee Arthroplasty Increases Strength and Function in Older Adults With Severe Osteoarthritis

Preparing for the stress of total knee arthroplasty (TKA) surgery by exercise training (prehabilitation) may improve strength and function before surgery and, if effective, has the potential to contribute to postoperative recovery. Subjects with severe osteoarthritis (OA), pain intractable to medicine and scheduled for TKA were randomized into a usual care (UC) group (n = 36) or usual care and exercise (UC + EX) group (n = 35). The UC group maintained normal daily activities before their TKA. The UC + EX group performed a comprehensive prehabilitation program that included resistance training using bands, flexibility, and step training at least 3 times per week for 4-8 weeks before their TKA in addition to UC. Leg strength (isokinetic peak torque for knee extension and flexion) and ability to perform functional tasks (6-minute walk, 30 second sit-to-stand repetitions, and the time to ascend and descend 2 flights of stairs) were assessed before randomization at baseline (T1) and 1 week before the subject\u27s TKA (T2). Repeated-measures analysis of variance indicated a significant group by time interaction (p \u3c 0.05) for the 30-second sit-to-stand repetitions, time to ascend the first flight of stairs, and peak torque for knee extension in the surgical knee. Prehabilitation increased leg strength and the ability to perform functional tasks for UC + EX when compared to UC before TKA. Short term (4-8 weeks) of prehabilitation was effective for increasing strength and function for individuals with severe OA. The program studied is easily transferred to a home environment, and clinicians working with this population should consider prehabilitation before TKA. [PUBLICATION ABSTRACT

Cardiovascular Fitness Moderates the Relations Between Estimates of Obesity and Physical Self-Perceptions in Rural Elementary School Students

Background: Levels of physical activity decline throughout childhood. Children’s physical self-perceptions have been found to relate to their physical activity. Understanding the relationships among physical selfperceptions, obesity, and physical activity could have important implications for interventions in children. Methods: The current study investigated the moderating effect of cardiovascular fitness (CVF, heart rate recovery from a 3-minute step test) on the relationship between obesity (BMI, waist circumference) and physical self-perceptions (athletic competence, physical appearance) in 104 fourth- and fifth-grade children from a small rural community. Results: Hierarchical regression analyses indicated that CVF moderated the relations between BMI and waist circumference on athletic competence. For children with lower fitness, higher waist circumference was associated with lower athletic competence, while for children with higher fitness levels, higher BMI was associated with higher athletic competence. Results also indicated that both BMI and waist circumference were negatively related to physical appearance. CVF moderated these relations such that only children with lower fitness, greater BMI and waist circumference was associated with poorer physical appearance scores. Conclusions: Implications include the need for support of fitness programs to promote psychological well-being and to investigate the relationship between obesity and physical self-perceptions within the context of fitness

Methods-Motivational Interviewing Approach for Enhanced Retention and Attendance.

IntroductionSuboptimal and differential participant engagement in randomized trials-including retention at primary outcome assessments and attendance at intervention sessions-undermines rigor, internal validity, and trial conclusions.MethodsFirst, this study describes Methods-Motivational Interviewing approach and strategies for implementation. This approach engages potential participants before randomization through interactive, prerequisite orientation sessions that illustrate the scientific rationale behind trial methods in accessible language and use motivational interviewing to diffuse ambivalence about participation. Then, this study examines the potential improvements in retention (proportion of participants assessed at follow-up visits) and attendance (e.g., mean percentage of intervention sessions attended, percentage of participants who attended 0 sessions) in 3 randomized weight-management trials that quickly added prerequisite orientations to their protocols following early signs of suboptimal or differential participant engagement (Supporting Health by Integrating Nutrition and Exercise [2009-2013, n=194]; Get Social [2016-2020, n=217]; GestationaL Weight Gain and Optimal Wellness [2014-2018, n=389]). Using a pre-post analytical design, adjusted estimates from regression models controlling for condition and assessment timepoint (analyses from 2020) are reported.ResultsAfter adding prerequisite orientations, all 3 trials attained higher participant engagement. Retention at assessments was 11.4% and 17.3% higher (Get Social and Supporting Health by Integrating Nutrition and Exercise, respectively). Mean percentage of attendance at intervention sessions was 8.8% higher (GestationaL Weight Gain and Optimal Wellness), and 10.1% fewer participants attended 0 intervention sessions (Get Social). Descriptively, all the remaining retention and attendance outcomes were consistently higher but were nonsignificant. Across the trials, adding prerequisite orientations did not impact the proportion of eligible participants enrolled or the baseline demographics.ConclusionsThe Methods-Motivational Interviewing approach shows promise for increasing the rigor of randomized trials and is readily adaptable to in-person, webinar, and conference call formats.Trial registrationAll 3 trials are registered at www.clinicaltrials.gov (Supporting Health by Integrating Nutrition and Exercise: NCT00960414; Get Social: NCT02646618; and GestationaL Weight Gain and Optimal Wellness: NCT02130232)