Browsing by Author "Broussard, Josiane, committee member"
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Item Open Access 1 month effect of breaking up sedentary activity on insulin sensitivity and glucose homeostasis in free-living overweight/obese adults(Colorado State University. Libraries, 2019) Schreck, Laura M., author; Hickey, Matthew, advisor; Bergouignan, Audrey, advisor; Broussard, Josiane, committee member; Melby, Christopher, committee memberSedentary behavior (SB) triggers an inability to adjust substrate use to substrate availability (low metabolic flexibility, MF), which may precede glucose intolerance in the pathogenesis of insulin resistance. We and others have shown that frequent interruptions in SB leads to improved glycemic control, however the underlying role of MF in this process is unknown. This study examined the effects of breaking up SB on MF and glucose metabolism in free-living overweight and obese adults. To distinguish effects of breaking up SB from being physically active, we also studied a group where participants performed a single energy matched continuous bout of exercise. Physically inactive, adults (12F/9M, mean±SD, age: 33±8 yr, BMI: 29.5±3.3 kg/m2) were randomly assigned to a 4 week intervention consisting of brisk walking for 5 min each hour for 10h, 5 d/wk (MICRO, n=10), or 4 weeks of an intervention consisting of one continuous 45 min bout of exercise per day, 5d/wk (ONE, n=9). Outcomes assessed at baseline and after each intervention included: MF (waking respiratory quotient, RQ, minus sleeping RQ as measured in a whole room calorimeter), insulin sensitivity (SI, IVGTT), 24h glycemia (continuous glucose monitor), 24h glucose oxidation (U13C glucose tracer), SB, time spent standing, time spent stepping (ActivPAL) and TEE (double labeled water). Groups were similar on all outcome variables at baseline. Linear mixed models evaluated intervention and intervention-by-group effects. MICRO and ONE decreased time sitting and increased time stepping with no significant changes in TEE. Compared to ONE, MICRO decreased 24h glycemic variability (p=0.06), improved the acute whole body insulin sensitivity (p=0.08) and acute insulin response to glucose (AIRg) (p=0.02) , maintained exogenous glucose oxidation (p<0.03) and improved MF (p=0.02). Independent of time sitting and stepping, breaking up SB improves glucose homeostasis and MF. The effects of such an intervention in persons with type 2 diabetes warrants further study.Item Open Access Evaluating central mechanisms for age-related force control deficits of the legs(Colorado State University. Libraries, 2019) Hanson, Moriah R., author; Fling, Brett W., advisor; Broussard, Josiane, committee member; Stephens, Jaclyn, committee memberAdvancing age is accompanied by several motor control impairments, including increased movement and force variability. Specifically, older adults display more variable and less accurate submaximal forces than young adults, which have been associated with fall risk in the aged population. These motor control changes take place in muscles in both the upper and lower limbs, and the mechanisms of these alterations are multifactorial, including sources in the peripheral and central nervous systems. Furthermore, inhibitory signaling in the motor cortex is related to force variability in small hand muscles, as well as to coordination of the legs during walking. It is unknown, however, whether inhibition is associated with force variability in the legs. Therefore, the purpose of this study was to assess the relationship between motor cortex inhibition and force variability in the quadriceps muscles of young and old adults. We measured quadriceps force variability and accuracy during a 2-minute force matching task and inhibition via the cortical silent period in 14 young and 15 old adults. Older adults produced more variable and less accurate forces than the young adults, though these differences were not significant. Additionally, older adults displayed less inhibition in their right cortical hemisphere than young adults, as well as interhemispheric inhibitory differences. Specifically, the left hemisphere displayed more inhibition than the right hemisphere in old adults. Furthermore, young adults with more inhibition generally produced more variable and less accurate forces than young adults with less inhibition, while older adults with more inhibition displayed less variable and more accurate forces. The between- and within-group differences in inhibition may point to age-related decline in right hemispheric function. Moreover, between-group differences in inhibition and force variability associations indicate a shift in the inhibitory control of movement, which is a similar finding to previous work on inhibition and lower limb coordination.Item Open Access Identifying novel molecular mechanisms of healthspan using multi-omics(Colorado State University. Libraries, 2023) Smith, Meghan Elizabeth, author; LaRocca, Tom, advisor; Hamilton, Karyn, committee member; Broussard, Josiane, committee member; Ehrhart, Nicole, committee memberAn important goal in research on aging is to extend healthspan, the period of life spent healthy and disease-free. Next-generation sequencing and other emerging bioinformatics technologies (e.g., RNA-seq/transcriptomics, epigenetic profiling, and proteomics) have made it possible to broadly profile potential molecular mediators of aging, and perhaps identify therapeutic targets. The studies in this dissertation focus on using transcriptomics and complementary "multi-omics" strategies to characterize novel cellular mechanisms of aging, and to determine their relevance to systemic/functional health in humans. With the guidance of my mentoring team, I completed three studies in which I identified novel mediators of healthspan-related exercise training responsiveness, age-related inflammation, and cognitive/motor function decline in middle-aged and older adults. One particularly novel focus among these studies was the role of non-coding repetitive RNAs (derived from transposable elements) in healthspan. Transposable elements have been linked to known mechanisms of aging, and this topic is reviewed at the start of this dissertation to provide perspective on their role in the context of research on aging biology. Collectively, my findings represent new ideas for targetable genes and proteins that may influence human healthspan.Item Embargo Promoting adherence to cognitive-behavioral therapy for insomnia in the medically complex case(Colorado State University. Libraries, 2023) Lovell, Emily R., author; Eakman, Aaron, advisor; Weaver, Jennifer, committee member; Broussard, Josiane, committee memberObjective. The purpose of this study is to explore how a medically complex case responded to cognitive-behavioral therapy for insomnia (CBT-I) in a community-based setting based on adherence to treatment recommendations. Method. A mixed-methods retrospective case study design was used to explore answers to two research questions: 1) How effective is CBT-I for an individual with insomnia comorbid with bipolar disorder? 2) How is CBT-I tailored for an individual with insomnia comorbid with bipolar disorder in a real-world setting? 3) How do we assess adherence to CBT-I delivered by an occupational therapist? Data sources included sleep diaries, service logs, pre-/post-treatment assessments, and interviews with the client and therapist. Results. Improvements in sleep latency, wake after sleep onset, early morning awakening, total sleep time, and sleep efficiency were observed. The most noteworthy improvements were a gain of almost two hours of total sleep time and a post-treatment SE of 95%. Likewise, scores on the Insomnia Severity Index, Epworth Sleepiness Scale, Sleep Disorders Symptoms Checklist-25, Dysfunctional Beliefs and Attitudes about Sleep scale, Sleep Hygiene Index, Quick Inventory of Depressive Symptomatology, and Patient Health Questionnaire-9 all improved to the extent that the client no longer met criteria for chronic insomnia. Overall adherence to the behavior components of CBT-I was very high. High motivation and scheduling and engaging in activities emerged as factors that promote adherence from the interview conducted with the client. A therapeutic relationship emerged as a factor that promotes adherence from the interview conducted with the therapist. Conclusion. CBT-I can be safely delivered by occupational therapists to individuals with bipolar disorder. Large improvements in sleep were observed and the client had high adherence to treatment protocols.Item Open Access Reallocating time to physical activity and sleep: associations with quality of life and body mass index in cancer survivors(Colorado State University. Libraries, 2021) Hidde, Mary, author; Leach, Heather, advisor; Broussard, Josiane, committee member; Lyden, Kate, committee member; Henry, Kim, committee memberIntroduction: Quality of Life (QOL) and Body Mass Index (BMI) are important outcomes for cancer survivors due to their association with cancer-related morbidity and mortality. Lifestyle behaviors including physical activity (PA), sedentary time, and sleep are all potential intervention targets to improve QOL and BMI. The effect of these activities on QOL and BMI is most often studied in isolation despite the interdependent nature of these behaviors; time cannot be increased in one activity without decreasing time in another. Since these behaviors are often studied in isolation, it is difficult to assess if an improvement in QOL or BMI is attributed to increasing positive behaviors (i.e., PA or sleep), or decreasing negative behaviors (i.e., sedentary time). The growing interest around 24-hour activity patterns has increased researcher interest in objective measurement of PA and sleep using accelerometers. However, this currently requires researchers to utilize one device to measure sleep (i.e., Actiwatch) and one to measure waking behaviors (i.e., activPAL). This has led to high research costs and burden since the Actiwatch cannot measures waking behaviors and, until recently, the activPAL could not detect time in bed (TIB), limiting researcher's ability to objectively collect 24-hour activity data. In order to move the world of 24-hour activity forward and delineate the role time reallocations throughout the day affect pertinent cancer-related outcomes, additional research must be conducted to explore solutions to the high research costs and burden associated with 24-hour activity measurement. Therefore, the purpose of this dissertation is to (1) evaluate if the new activPAL algorithm designed to measure TIB can estimate TIB similarly to the valid and reliable Actiwatch and 2) evaluate, using an Isotemporal substitution model, the effects of reallocating time from one activity to another on QOL and BMI using accelerometry (Actiwatch and activPAL pending results of aim 1) to measure 24-hour activities. Methods: The activPAL algorithm's ability to measure TIB was evaluated using a cross-sectional analysis of participants (n=85) undergoing a time-restricted feeding study. Participants (for all studies) wore the activPAL accelerometer to measure waking behaviors and the Actiwatch to measure sleeping behaviors for 7 days, 24-hours per day. Repeated measures mixed effects models and Bland-Altman plots were used to compare the activPAL TIB estimates to the Actiwatch TIB estimate with type of device and day of wear as fixed effects and participant as a random effect. TIB results were then utilized in a cross-sectional analyses of cancer survivors (n=73) within 60 months of surgery, chemotherapy, and/or radiation. In addition to wearing the activPAL and Actiwatch, participants completed the Functional Assessment of Cancer Therapy-General (FACT-G) to measure QOL. Participants self-reported height and weight to calculate BMI. Demographics were calculated using mean ± standard deviation or frequencies (%). Isotemporal substitution models were used to evaluate the effects of reallocating 30 minutes of each activity to another. Statistical significance for all studies was set at p<.05. Results: The activPAL accelerometer does not estimate TIB similarly to the Actiwatch. Additionally, no significant interaction was observed for type of accelerometer and day of wear. There were no statistically significant reallocations for total QOL score or the included subscales. However for BMI, reallocating 30 minutes of sleep to sedentary time or moving 30 minutes of sedentary time to light PA did result in statistically significant changes in BMI. There were no statistically significant reallocations by moving moderate-vigorous PA to other activities of interest. Despite no statistical significance for QOL, reallocating time from sedentary time or light PA to MVPA resulted in clinically meaningful increases in QOL (>4 points). Conclusion: Estimates of TIB from the activPAL and Actiwatch accelerometers were not similar, suggesting that researchers who are interested in the 24-hour activity cycle will continue to require the use of both accelerometers to measure both sleep and active/waking behaviors. Results of reallocating time on QOL and BMI indicate that in addition to MVPA, sleep, and light PA are essential behaviors for cancer survivors. The work presented in this dissertation can provide a starting point for the development of 24-hour activity guidelines for improving BMI and QOL in cancer survivors; however, additional time reallocation studies using a larger sample size in order to include bouted and non-bouted activity time as well as more detailed measures of body composition (i.e., dual x-ray absorptiometry) are needed to further understand the role the 24-hour activity cycle has on BMI and QOL in cancer survivors.Item Open Access The rhythm of cognition: older adulthood edition(Colorado State University. Libraries, 2024) McDermott, Cynthia, author; Bielak, Allison, advisor; Fenton, Melissa, advisor; Broussard, Josiane, committee memberCircadian rhythm is a delicate function that regulates multiple processes, such as cognition, sleep, and appetite. As humans age, their circadian rhythms shift to become earlier, resulting in their cognitive peak performance being earlier in the day. This study's main goals were to investigate if older adults (N = 139; Mage = 69.22; range = 60-89) who completed online cognitive tasks over 7 days at peak hours performed better than those who completed them at off-peak hours, as well as to determine if there were specific cognitive tasks that older adults did better on during these peak times. Four cognitive tasks were used to measure working memory, inductive reasoning, episodic memory, and processing speed. As tested by Repeated Measures Analysis of Variance (RMANOVA), results showed no significant between-group differences, which indicated that the different test timing groups did not differ in their cognitive performance. The RMANOVA results also revealed no significant effects of test timing groups for any of the individual cognitive tasks. These findings are inconsistent with the little research available regarding on- and off-peak test timing in older adults and suggest the need for a more well-controlled study focused on older adults. If a more reliable on-peak test time for older participants is identified, then clinicians who test cognition could have the ability to detect cognitive decline earlier on. Ultimately, this could lead to earlier diagnoses or recognition of abnormal changes in cognition.