Matching Items (22)
Description
The shape of glucose response and one hour (1-hr) glucose during an oral glucose tolerance test (OGTT) are emerging biomarkers for type 2 diabetes. The purpose of this study was two-fold: (1) to investigate the utility of these novel biomakers to differentiate type 2 diabetes risk in Latino youth, and (2) to examine the genetic determinants in a Latino population.
Data from the ASU Arizona Insulin Registry (AIR) registry and the USC Study of Latino Adolescents at Risk for diabetes project were used to test the cross-sectional and prospective utility of novel biomarkers to identify youth at risk for type 2 diabetes. Pediatric and adult data from the ASU AIR registry were assessed to examine the association of single nucleotide polymorphisms (SNPs) with type 2 diabetes risk. Three KCNQ1 SNPs (rs151290; rs2237892; rs2237895) were examined as novel genetic variants for type 2 diabetes in Latinos.
Latino youth with a biphasic response in the AIR registry exhibited significantly better β-cell function (P < 0.05) compared to youth with a monophasic response. Additionally, Latino youth with a 1-hr glucose ≥155 mg/dL exhibited a significantly greater decline in β-cell function over 8 years compared with the <155 mg/dL group (β=-327.8±126.2, P = 0.01). Moreover, a 1-hr glucose ≥155 mg/dL was associated with a 2.5 times greater risk for developing prediabetes over time (P = 0.0001). 1-hr glucose was the most powerful predictor of prediabetes (area under the receiver operating characteristic curve=0.73) when compared to the traditional biomarkers including HbA1c (0.58), fasting (0.67), and 2-hr glucose (0.64). Two KCNQ1 SNPs (rs151290 and rs2237892) exhibited significant associations with type 2 diabetes risk factors. For the novel glycemic markers, 15 SNPs were associated with the glucose response curve, while 18 SNPs were associated with 1-hr glucose.
These data suggest that glucose response curve and 1-hr glucose during an OGTT independently differentiate type 2 diabetes risk among Latino youth. Furthermore, it was successful to replicate the association of type 2 diabetes risk with 2 KCNQ1 SNPs in a Latino population. Data suggest that novel glycemic biomarkers are influenced by genetic background in this high-risk population.
Data from the ASU Arizona Insulin Registry (AIR) registry and the USC Study of Latino Adolescents at Risk for diabetes project were used to test the cross-sectional and prospective utility of novel biomarkers to identify youth at risk for type 2 diabetes. Pediatric and adult data from the ASU AIR registry were assessed to examine the association of single nucleotide polymorphisms (SNPs) with type 2 diabetes risk. Three KCNQ1 SNPs (rs151290; rs2237892; rs2237895) were examined as novel genetic variants for type 2 diabetes in Latinos.
Latino youth with a biphasic response in the AIR registry exhibited significantly better β-cell function (P < 0.05) compared to youth with a monophasic response. Additionally, Latino youth with a 1-hr glucose ≥155 mg/dL exhibited a significantly greater decline in β-cell function over 8 years compared with the <155 mg/dL group (β=-327.8±126.2, P = 0.01). Moreover, a 1-hr glucose ≥155 mg/dL was associated with a 2.5 times greater risk for developing prediabetes over time (P = 0.0001). 1-hr glucose was the most powerful predictor of prediabetes (area under the receiver operating characteristic curve=0.73) when compared to the traditional biomarkers including HbA1c (0.58), fasting (0.67), and 2-hr glucose (0.64). Two KCNQ1 SNPs (rs151290 and rs2237892) exhibited significant associations with type 2 diabetes risk factors. For the novel glycemic markers, 15 SNPs were associated with the glucose response curve, while 18 SNPs were associated with 1-hr glucose.
These data suggest that glucose response curve and 1-hr glucose during an OGTT independently differentiate type 2 diabetes risk among Latino youth. Furthermore, it was successful to replicate the association of type 2 diabetes risk with 2 KCNQ1 SNPs in a Latino population. Data suggest that novel glycemic biomarkers are influenced by genetic background in this high-risk population.
ContributorsKim, Joon Young (Author) / Shaibi, Gabriel Q (Thesis advisor) / Mandarino, Lawrence J (Committee member) / Coletta, Dawn K (Committee member) / De Filippis, Elena A (Committee member) / Arizona State University (Publisher)
Created2015
Description
In adults, consuming a high-fat meal can induce endothelial dysfunction while exercise may mitigate postprandial endothelial dysfunction. Whether exercise is protective against postprandial endothelial dysfunction in obese youth is unknown. The purpose of this study was to determine if high-intensity interval exercise (HIIE) performed the evening prior to a high-fat meal protects against postprandial endothelial dysfunction in obese adolescent males. Fourteen obese adolescent males (BMI%tile=98.5±0.6; 14.3±1.0yrs) completed the study. After initial screening, participants arrived, fasted at 9:00 in the morning where brachial artery flow-mediated dilation (FMD) was measured using duplex ultrasound after 20min of supine rest (7.0±3.0%) and completed a maximal exercise test on a cycle ergometer (VO2peak=2.6±0.5 L/min). Participants were randomized and completed 2 conditions: a morning high-fat meal challenge with evening prior HIIE (EX+M) or a morning high-fat meal challenge without prior exercise (MO). The EX+M condition included a single HIIE session on a cycle ergometer (8 X 2min at ≥90%HRmax, with 2min active recovery between bouts, 42min total) which was performed at 17:00 the evening prior to the meal challenge. In both conditions, a mixed-meal was tailored to participants body weight consisting of 0.7g of fat/kg of body weight consumed (889±95kcal; 65% Fat, 30% CHO). FMD was measured at fasting (>10hrs) and subsequently measured at 2hr and 4hr after high-fat meal consumption. Exercise did not improve fasting FMD (7.5±3.0 vs. 7.4±2.8%, P=0.927; EX+M and MO, respectively). Despite consuming a high-fat meal, FMD was not reduced at 2hr (8.4±3.4 vs. 7.6±3.9%; EX+M and MO, respectively) or 4hr (8.8±3.9 vs. 8.6±4.0%; EX+M and MO, respectively) in either condition and no differences were observed between condition (p(condition*time)=0.928). These observations remained after adjusting for baseline artery diameter and shear rate. We observed that HIIE, the evening prior, had no effect on fasting or postprandial endothelial function when compared with a meal only condition. Future research should examine whether exercise training may be able to improve postprandial endothelial function rather than a single acute bout in obese youth.
ContributorsRyder, Justin Ross (Author) / Shaibi, Gabriel Q (Thesis advisor) / Gaesser, Glenn A (Committee member) / Vega-Lopez, Sonia (Committee member) / Crespo, Noe C (Committee member) / Katsanos, Christos (Committee member) / Arizona State University (Publisher)
Created2014
Description
Among the general US population, cardiovascular disease (CVD) is the main cause of mortality for Mexican-Americans. CVD is less prevalent among Mexican-Americans than non-Hispanic Whites or African Americans. However, there is limited research regarding the factors associated with increased CVD risk among Mexican-Americans. Thus, this cross-sectional study was conducted to evaluate the effects of non-biological factors (income, education, employment, acculturation) and diet on CVD risk factors in 75 Mexican-American adults (26 males, 49 females; age=37.6±9.3 y, BMI=28.9±5.3 kg/m2, systolic BP=117±11 mmHg, diastolic BP=73±9 mmHg, LDL cholesterol=114±32 mg/dL, HDL cholesterol=44±11 mg/dL, triglycerides=115±61 mg/dL, serum glucose=92±7 mg/dL). Aside from collecting anthropometric measurements, blood pressure, and measuring fasting blood lipids, glucose, and insulin, information about participants' socioeconomic status, income, employment, education, and acculturation were gathered using a survey. Diet data was collected using the Southwestern Food Frequency Questionnaire. Weight, BMI, and waist circumference were significantly greater for those with a monthly income of <$3000 than for those earning >$3000 (81±15 kg vs. 71±15 kg; 29.8±4.6 kg/m2 vs. 26.5±5.1 kg/m2; 98±12 cm vs. 89±14 cm; respectively) and with an education level of high school graduate or less than for those with some college (84±16 kg vs. 72±14 kg; 30.6±4.2 kg/m2 vs. 26.9±4.9 kg/m2; 100±11 cm vs. 91±13 cm; respectively). HDL-C was higher for those with a monthly income of >$3000 than those earning <$3000 (49±12 mg/dL vs. 41±10 mg/dL), those with some college education than those with high school or less (47±10 mg/dL vs. 37±9 mg/dL), and for those employed than those not employed (46±10 mg/dL vs. 40±12 mg/dL). There was no association between acculturation and CVD risk factors. Percent of energy consumed from fat was greater and percent of energy from carbohydrates was lower in those earning <$3000 monthly than those earning >$3000 (32±5% vs. 29±3%; 52±8% vs. 56±4%; respectively). Greater acculturation to the Anglo culture was negatively correlated with body fat percentage (r=-0.238, p=0.043) and serum glucose (r=-0.265, p=0.024). Overall, these results suggest that factors related to sociocultural and socioeconomic status may affect cardiometabolic disease risk in Mexican-Americans living in the Phoenix metropolitan area.
ContributorsFarr, Kristin Jennette (Author) / Vega-Lopez, Sonia (Thesis advisor) / Shaibi, Gabriel Q (Committee member) / Mayol-Kreiser, Sandra N (Committee member) / Arizona State University (Publisher)
Created2011
Description
Mexican Americans have an increased risk for type 2 diabetes and premature cardiovascular disease (CVD). The association of hyperglycemia with traditional CVD risk factors in this population has been established, but there is limited data regarding other non-traditional CVD risk factors. Thus, this cross-sectional study was conducted to evaluate CVD risk among Mexican Americans by measuring concentrations of lipids, high-sensitivity C-reactive protein (hsCRP), and cholesterol in low-density-lipoprotein (LDL) and high-density-lipoprotein (HDL) subfractions. Eighty overweight/obese Mexican-American adults participating in the Maricopa Insulin Resistance Initiative were randomly selected from each of the following four groups (n = 20 per group): nomolipidemic
ormoglycemic controls (NC), dyslipidemic
ormoglycemic (DN), dyslipidemic/prediabetic (DPD) and dyslipidemic/diabetic (DD). Total cholesterol (TC) was 30% higher among DD than in NC participants (p<0.0001). The DPD group had 27% and 12% higher LDL-C concentrations than the NC and DN groups, respectively. Similarly, LDL-C was 29% and 13% higher in DD than in NC and DN participants (p=0.013). An increasing trend was observed in %10-year CVD risk with increasing degree of hyperglycemia (p<0.0001). The NC group had less cholesterol in sdLDL particles than dyslipidemic groups, regardless of glycemic status (p<0.0001). When hyperglycemia was part of the phenotype (DPD and DD), there was a greater proportion of total and HDL-C in sHDL particles in dyslipidemic individuals than in NC (p=0.023; p<0.0001; respectively). Percent 10-year CVD risk was positively correlated with triglyceride (TG) (r=0.384, p<0.0001), TC (r=0.340, p<0.05), cholesterol in sdLDL(r=0.247; p<0.05), and TC to HDL-C ratio (r=0.404, p<0.0001), and negatively correlated with HDL-C in intermediate and large HDL(r=-0.38, p=0.001; r=0.34, p=0.002, respectively). The TC/HDL-C was positively correlated with cholesterol in sdLDL particles (r=0.698, p<0.0001) and HDL-C in sHDL particles (r=0.602, p<0.0001), and negatively correlated with cholesterol in small (r=-0.35, p=0.002), intermediate (r=-0.91, p<0.0001) and large (r=-0.84, p<0.0001) HDL particles, and HDL-C in the large HDL particles (r=-0.562, p<0.0001). No significant association was found between %10-year CVD risk and hsCRP. Collectively, these results corroborate that dyslipidemic Mexican-American adults have higher CVD risk than normolipidemic individuals. Hyperglycemia may further affect CVD risk by modulating cholesterol in LDL and HDL subfractions.
ormoglycemic controls (NC), dyslipidemic
ormoglycemic (DN), dyslipidemic/prediabetic (DPD) and dyslipidemic/diabetic (DD). Total cholesterol (TC) was 30% higher among DD than in NC participants (p<0.0001). The DPD group had 27% and 12% higher LDL-C concentrations than the NC and DN groups, respectively. Similarly, LDL-C was 29% and 13% higher in DD than in NC and DN participants (p=0.013). An increasing trend was observed in %10-year CVD risk with increasing degree of hyperglycemia (p<0.0001). The NC group had less cholesterol in sdLDL particles than dyslipidemic groups, regardless of glycemic status (p<0.0001). When hyperglycemia was part of the phenotype (DPD and DD), there was a greater proportion of total and HDL-C in sHDL particles in dyslipidemic individuals than in NC (p=0.023; p<0.0001; respectively). Percent 10-year CVD risk was positively correlated with triglyceride (TG) (r=0.384, p<0.0001), TC (r=0.340, p<0.05), cholesterol in sdLDL(r=0.247; p<0.05), and TC to HDL-C ratio (r=0.404, p<0.0001), and negatively correlated with HDL-C in intermediate and large HDL(r=-0.38, p=0.001; r=0.34, p=0.002, respectively). The TC/HDL-C was positively correlated with cholesterol in sdLDL particles (r=0.698, p<0.0001) and HDL-C in sHDL particles (r=0.602, p<0.0001), and negatively correlated with cholesterol in small (r=-0.35, p=0.002), intermediate (r=-0.91, p<0.0001) and large (r=-0.84, p<0.0001) HDL particles, and HDL-C in the large HDL particles (r=-0.562, p<0.0001). No significant association was found between %10-year CVD risk and hsCRP. Collectively, these results corroborate that dyslipidemic Mexican-American adults have higher CVD risk than normolipidemic individuals. Hyperglycemia may further affect CVD risk by modulating cholesterol in LDL and HDL subfractions.
ContributorsNeupane, Srijana (Author) / Vega-Lopez, Sonia (Thesis advisor) / Shaibi, Gabriel Q (Committee member) / Johnston, Carol S (Committee member) / Arizona State University (Publisher)
Created2011
Description
Background: Heart failure is the leading cause of hospitalization in older adults and has the highest 30-day readmission rate of all diagnoses. An estimated 30 to 60 percent of older adults lose some degree of physical function in the course of an acute hospital stay. Few studies have addressed the role of posture and mobility in contributing to, or improving, physical function in older hospitalized adults. No study to date that we are aware of has addressed this in the older heart failure population.
Purpose: To investigate the predictive value of mobility during a hospital stay and patterns of mobility during the month following discharge on hospital readmission and 30-day changes in functional status in older heart failure patients.
Methods: This was a prospective observational study of 21 older (ages 60+) patients admitted with a primary diagnosis of heart failure. Patients wore two inclinometric accelerometers (rib area and thigh) to record posture and an accelerometer placed at the ankle to record ambulatory activity. Patients wore all sensors continuously during hospitalization and the ankle accelerometer for 30 days after hospital discharge. Function was assessed in all patients the day after hospital discharge and again at 30 days post-discharge.
Results: Five patients (23.8%) were readmitted within the 30 day post-discharge period. None of the hospital or post-discharge mobility measures were associated with readmission after adjustment for covariates. Higher percent lying time in the hospital was associated with slower Timed Up and Go (TUG) time (b = .08, p = .01) and poorer hand grip strength (b = -13.94, p = .02) at 30 days post-discharge. Higher daily stepping activity during the 30 day post-discharge period was marginally associated with improvements in SPPB scores at 30 days (b = <.001, p = .06).
Conclusion: For older heart failure patients, increased time lying while hospitalized is associated with slower walking time and poor hand grip strength 30 days after discharge. Higher daily stepping after discharge may be associated with improvements in physical function at 30 days.
Purpose: To investigate the predictive value of mobility during a hospital stay and patterns of mobility during the month following discharge on hospital readmission and 30-day changes in functional status in older heart failure patients.
Methods: This was a prospective observational study of 21 older (ages 60+) patients admitted with a primary diagnosis of heart failure. Patients wore two inclinometric accelerometers (rib area and thigh) to record posture and an accelerometer placed at the ankle to record ambulatory activity. Patients wore all sensors continuously during hospitalization and the ankle accelerometer for 30 days after hospital discharge. Function was assessed in all patients the day after hospital discharge and again at 30 days post-discharge.
Results: Five patients (23.8%) were readmitted within the 30 day post-discharge period. None of the hospital or post-discharge mobility measures were associated with readmission after adjustment for covariates. Higher percent lying time in the hospital was associated with slower Timed Up and Go (TUG) time (b = .08, p = .01) and poorer hand grip strength (b = -13.94, p = .02) at 30 days post-discharge. Higher daily stepping activity during the 30 day post-discharge period was marginally associated with improvements in SPPB scores at 30 days (b = <.001, p = .06).
Conclusion: For older heart failure patients, increased time lying while hospitalized is associated with slower walking time and poor hand grip strength 30 days after discharge. Higher daily stepping after discharge may be associated with improvements in physical function at 30 days.
ContributorsFloegel, Theresa A (Author) / Buman, Matthew P (Thesis advisor) / Hooker, Steven (Committee member) / Dickinson, Jared (Committee member) / DerAnanian, Cheryl (Committee member) / McCarthy, Marianne (Committee member) / Arizona State University (Publisher)
Created2015
Description
Background. Effects of lifestyle interventions on early biomarkers of oxidative stress and CVD risk in youth with prediabetes are unknown. Objective. To evaluate the effects of a lifestyle intervention to prevent type 2 diabetes among obese prediabetic Latino adolescents on oxidized lipoproteins. Design: In a quasi-experimental design, 35 adolescents (51.4% male, age 15.5(1.0) y, body mass index (BMI) percentile 98.5(1.2), and glucose 2 hours after an oral glucose tolerance test-OGTT 141.2(12.2) mg/dL) participated in a 12-week intervention that included weekly exercise (three 60 min-sessions) and nutrition education (one 60 min-session). Outcomes measured at baseline and post-intervention were: fasting oxidized LDL and oxidized HDL (oxLDL and oxHDL) as oxidative stress variables; dietary intake of fresh fruit and vegetable (F&V) and fitness (VO2max) as behavioral variables; weight, BMI, body fat, and waist circumference as anthropometric variables; fasting glucose and insulin, 2hour glucose and insulin after an OGTT, insulin resistance (HOMA-IR), and lipid panel (triglycerides, total cholesterol, VLDL-c, LDL-c, HDL-c, and Non-HDL) as cardiometabolic variables. Results. Comparing baseline to post-intervention, significant decreases in oxLDL concentration were shown (51.0(14.0) and 48.7(12.8) U/L, p=0.022); however, the intervention did not decrease oxHDL (395.2(94.6) and 416.1(98.4) ng/mL, p=0.944). F&V dietary intake (116.4(97.0) and 165.8(91.0) g/d, p=0.025) and VO2max (29.7(5.0) and 31.6(4.7) ml*kg-1*min-1, p<0.001) significantly increased. Within-subjects correlations between changes in F&V intake and oxidized lipoproteins, adjusted for VO2max changes, were non-significant (R=-0.15, p=0.52 for oxLDL; R=0.22, p=0.25 for oxHDL). Anthropometric variables were significantly reduced (weight -1.3% p=0.042; BMI -2.2% and BMI percentile -0.4%, p=0.001; body fat -6.6% and waist circumference -1.8%, p=0.025). Cardiometabolic variables significantly improved, including reductions in glucose 2hour (-19.3% p<0.001), fasting insulin (-12.9% p=0.008), insulin 2hour (-53.5% p<0.001), and HOMA-IR (-12.5% p=0.015), with 23 participants (66%) that reverted toward a normal glucose tolerance status. Most lipid panel significantly changed (triglycerides -10.2% p=0.032; total cholesterol -5.4% p=0.002; VLDL-c -10.4% p=0.029; HDL-c -3.2% p=0.022; and Non-HDL -5.5% p=0.0007). Conclusion. The intervention resulted in differential effects on oxidized lipoproteins and significant improvements in behavioral, anthropometric and cardiometabolic variables, reducing the high metabolic risk of obese prediabetic kids.
ContributorsRenteria Mexia, Ana Maria (Author) / Shaibi, Gabriel Q (Thesis advisor) / Vega-Lopez, Sonia (Committee member) / Swan, Pamela D (Committee member) / Olson, Micah L (Committee member) / Lee, Chong (Committee member) / Arizona State University (Publisher)
Created2017
Description
Many individual-level behavioral interventions improve health and well-being. However, most interventions exhibit considerable heterogeneity in response. Put differently, what might be effective on average might not be effective for specific individuals. From an individual’s perspective, many healthy behaviors exist that seem to have a positive impact. However, few existing tools support people in identifying interventions that work for them, personally.
One approach to support such personalization is via self-experimentation using single-case designs. ‘Hack Your Health’ is a tool that guides individuals through an 18-day self-experiment to test if an intervention they choose (e.g., meditation, gratitude journaling) improves their own psychological well-being (e.g., stress, happiness), whether it fits in their routine, and whether they enjoy it.
The purpose of this work was to conduct a formative evaluation of Hack Your Health to examine user burden, adherence, and to evaluate its usefulness in supporting decision-making about a health intervention. A mixed-methods approach was used, and two versions of the tool were tested via two waves of participants (Wave 1, N=20; Wave 2, N=8). Participants completed their self-experiments and provided feedback via follow-up surveys (n=26) and interviews (n=20).
Findings indicated that the tool had high usability and low burden overall. Average survey completion rate was 91%, and compliance to protocol was 72%. Overall, participants found the experience useful to test if their chosen intervention helped them. However, there were discrepancies between participants’ intuition about intervention effect and results from analyses. Participants often relied on intuition/lived experience over results for decision-making. This suggested that the usefulness of Hack Your Health in its current form might be through the structure, accountability, and means for self-reflection it provided rather than the specific experimental design/results. Additionally, situations where performing interventions within a rigorous/restrictive experimental set-up may not be appropriate (e.g., when goal is to assess intervention enjoyment) were uncovered. Plausible design implications include: longer experimental and phase durations, accounting for non-compliance, missingness, and proximal/acute effects, and exploring strategies to complement quantitative data with participants’ lived experiences with interventions to effectively support decision-making. Future work should explore ways to balance scientific rigor with participants’ needs for such decision-making.
One approach to support such personalization is via self-experimentation using single-case designs. ‘Hack Your Health’ is a tool that guides individuals through an 18-day self-experiment to test if an intervention they choose (e.g., meditation, gratitude journaling) improves their own psychological well-being (e.g., stress, happiness), whether it fits in their routine, and whether they enjoy it.
The purpose of this work was to conduct a formative evaluation of Hack Your Health to examine user burden, adherence, and to evaluate its usefulness in supporting decision-making about a health intervention. A mixed-methods approach was used, and two versions of the tool were tested via two waves of participants (Wave 1, N=20; Wave 2, N=8). Participants completed their self-experiments and provided feedback via follow-up surveys (n=26) and interviews (n=20).
Findings indicated that the tool had high usability and low burden overall. Average survey completion rate was 91%, and compliance to protocol was 72%. Overall, participants found the experience useful to test if their chosen intervention helped them. However, there were discrepancies between participants’ intuition about intervention effect and results from analyses. Participants often relied on intuition/lived experience over results for decision-making. This suggested that the usefulness of Hack Your Health in its current form might be through the structure, accountability, and means for self-reflection it provided rather than the specific experimental design/results. Additionally, situations where performing interventions within a rigorous/restrictive experimental set-up may not be appropriate (e.g., when goal is to assess intervention enjoyment) were uncovered. Plausible design implications include: longer experimental and phase durations, accounting for non-compliance, missingness, and proximal/acute effects, and exploring strategies to complement quantitative data with participants’ lived experiences with interventions to effectively support decision-making. Future work should explore ways to balance scientific rigor with participants’ needs for such decision-making.
ContributorsPhatak, Sayali Shekhar (Author) / Buman, Matthew P (Thesis advisor) / Hekler, Eric B. (Committee member) / Huberty, Jennifer L (Committee member) / Johnston, Erik W., 1977- (Committee member) / Swan, Pamela D (Committee member) / Arizona State University (Publisher)
Created2019
Description
The purpose of this study was to examine the feasibility and preliminary efficacy of a theory-driven and a atheoretical reminder point-of-choice (PoC) prompt interventions on reducing workplace sedentary behavior in office workers with self-reported low usage (<4 hours per day) of their sit-stand workstations in the standing position. The design of this study was a cross-over trial including randomization into either the theory-driven or atheoertical reminder condition, after completion of a no prompt control condition. Participants (N=19) included full-time, primarily female, Caucasian, middle-aged office workers. The primary aim of this study was to assess the feasibility of these two PoC prompt conditions on reducing sedentary behaviors through the use of a Therapy Evaluation Questionnaire. The secondary aim of this study was to assess the preliminary efficacy of the two PoC prompt conditions on reducing sedentary behaviors relative to no-prompt control using the activPAL micro device. For the primary aim, descriptive means adjusted for ordering effect were computed. For the secondary aim, mixed-effects regression models were used to cluster for observations within-persons and were adjusted for age, gender, race, job-type, and ordering effects. During the no-prompt control, participants spent 267.90 ± 68.01 sitting and 170.20 ± 69.34 min/8hr workday standing. The reminder PoC prompt condition significantly increased sanding time (b[se] = 24.52 [11.09], p=0.034) while the theory-driven PoC condition significantly decreased time spent in long sitting bouts b[se] = -34.86 [16.20], p=0.036), both relative to no prompt control. No statistically significant reductions in sitting time were seen in either PoC prompt condition. Furthermore, no statistically significant differences between the two PoC prompt conditions were observed. This study provides feasibility insight in addition to objective measures of sedentary behaviors regarding the use of PoC prompt interventions in the workplace.
ContributorsLarouche, Miranda (Author) / Buman, Matthew P (Thesis advisor) / Ainsworth, Barbara E (Thesis advisor) / Huberty, Jennifer L (Committee member) / Arizona State University (Publisher)
Created2018
Description
The purpose of this dissertation was 1) to develop noninvasive strategies to assess skeletal muscle size, architecture, and composition in young and old adults (study #1) and 2) evaluate the impact of chemotherapeutic treatment on skeletal muscle satellite cells and capillaries (study #2). For study #1 ultrasound images were obtained from the quadriceps muscles of young (8 m, 8 f) and older (7 m, 5 f) participants on two occasions, separated by 5-15 days. Images were collected while the participants were both standing and supine, and were analyzed for muscle thickness, pennation angle, and echogenicity. In addition, test-retest reliability and ICCs were evaluated for each posture and when imaging sites remained marked or were re-measured from visit #1 to visit #2. Generally, in both younger and older adults muscle thickness was greater and echogenicity was lower in the anterior quadriceps when images were collected standing versus supine. Maintaining the imaging site between visits did not influence test re-test reliability for either age group. Older adults exhibited smaller muscle thickness, lower pennation angle and increased echogenicity. Further, variability for the use of ultrasound to determine muscle thickness and pennation angle was greater in older versus younger adults. Findings from study #1 highlight several methodological considerations for US-based assessment of skeletal muscle characteristics that should be considered for improving reproducibility and generalizability of US to assess skeletal muscle characteristics and function across the aging spectrum. This is particularly relevant given the emerging use of ultrasound to assess skeletal muscle characteristics in healthy and clinical populations. In the second study, ovariectomized female Sprague-Dawley rats were randomized to receive three bi-weekly intraperitoneal injections of the chemotherapeutic drug, Doxorubicin (DOX) (4mg/kg; cumulative dose 12mg/kg) or vehicle (VEH; saline). Animals were euthanized 5d following the last injection, and the soleus (SOL) and extensor digitorum longus (EDL) muscles were dissected and prepared for immunohistochemical and RT-qPCR analyses. Relative to VEH, cross-sectional area (CSA) of the SOL and EDL muscle fibers were 26% and 33% smaller, respectively, in DOX animals (P<0.05). In the SOL satellite cell and capillary densities were 39% and 35% lower, respectively, in DOX animals (P<0.05), whereas in the EDL satellite cell and capillary densities were unaffected by DOX administration (P>0.05). In the SOL MYF5 mRNA expression was increased in DOX animals (P<0.05), while in the EDL MGF mRNA expression was reduced in DOX animals (P<0.05). Chronic DOX administration is associated with reduced fiber size in multiple skeletal muscles, however DOX appears to impact the satellite cell and capillary densities in a muscle-specific manner. These findings from study #2 highlight that therapeutic targets to protect skeletal muscle from DOX may vary across muscles. Collectively, these findings 1) improve the ability to examine muscle size and function in younger and older adults, and 2) identify promising therapeutic targets to protect skeletal muscle from the harmful effects of chemotherapy treatment.
ContributorsD'Lugos, Andrew (Author) / Dickinson, Jared M (Thesis advisor) / Buman, Matthew P (Committee member) / Gaesser, Glenn A (Committee member) / Huentelman, Matthew J (Committee member) / Katsanos, Christos S (Committee member) / Arizona State University (Publisher)
Created2018
Description
No studies have evaluated the impact of tracking resting energy expenditure (REE) and modifiable health behaviors on gestational weight gain (GWG). In this controlled trial, pregnant women aged >18 years (X=29.8±4.9 years) with a gestational age (GA) <17 weeks were randomized to Breezing™ (N=16) or control (N=12) for 13 weeks. The Breezing™ group used a real-time metabolism tracker to obtain REE. Anthropometrics, diet, and sleep data were collected every 2 weeks. Rate of GWG was calculated as weight gain divided by total duration. Early (GA weeks 14-21), late (GA weeks 21-28), and overall (GA week 14-28) changes in macronutrients, sleep, and GWG were calculated. Mediation models were constructed using SPSS PROCESS macro using a bootstrap estimation approach with 10,000 samples. The majority of women were non-Hispanic Caucasian (78.6%). A total of 35.7% (n=10), 35.7% (n=10), and 28.6% (n=8) were normal weight, overweight, and obese, respectively, with 83.3% (n=10) and 87.5% (n=14) of the Control and Breezing™ groups gaining above IOM GWG recommendations. At baseline, macronutrient consumption did not differ. Overall (Breezing™ vs. Control; M diff=-349.08±150.77, 95% CI: -660.26 to -37.90, p=0.029) and late (M diff=-379.90±143.89, 95% CI:-676.87 to -82.93, p=0.014) changes in energy consumption significantly differed between the groups. Overall (M diff=-22.45±11.03, 95% CI: -45.20 to 0.31, p=0.053), late (M diff=-23.16±11.23, 95% CI: -46.33 to 0.01, p=0.05), and early (M diff=20.3±10.19, 95% CI: -0.74 to 41.34, p=0.058) changes in protein differed by group. Nocturnal total sleep time differed by study group (Breezing vs. Control; M diff=-32.75, 95% CI: -68.34 to 2.84, p=0.069). There was a 11.5% increase in total REE throughout the study. Early changes in REE (72±211 kcals) were relatively small while late changes (128±294 kcals) nearly doubled. Interestingly, early changes in REE demonstrated a moderate, positive correlation with rates of GWG later in pregnancy (r=0.528, p=0.052), suggesting that REE assessment early in pregnancy may help predict changes in GWG. Changes in macronutrients did not mediate the relationship between the intervention and GWG, nor did sleep mediate relationships between dietary intake and GWG. Future research evaluating REE and dietary composition throughout pregnancy may provide insight for appropriate GWG recommendations.
ContributorsVander Wyst, Kiley Bernhard (Author) / Whisner, Corrie M (Thesis advisor) / Reifsnider, Elizabeth G. (Committee member) / Petrov, Megan E (Committee member) / Buman, Matthew (Committee member) / Shaibi, Gabriel Q (Committee member) / Arizona State University (Publisher)
Created2019