Browsing by Author "Sigal, Ronald J."

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    Changes in the Brain-Derived Neurotrophic Factor Are Associated with Improvements in Diabetes Risk Factors after Exercise Training in Adolescents with Obesity: The HEARTY Randomized Controlled Trial
    (2018-09-30) Walsh, Jeremy J.; D’Angiulli, Amedeo; Cameron, Jameason D.; Sigal, Ronald J.; Kenny, Glen P.; Holcik, Martin; Doucette, Steve; Alberga, Angela S.; Prud’homme, Denis; Hadjiyannakis, Stasia; Gunnell, Katie; Goldfield, Gary S.
    Obesity in youth increases the risk of type 2 diabetes (T2D), and both are risk factors for neurocognitive deficits. Exercise attenuates the risk of obesity and T2D while improving cognitive function. In adults, these benefits are associated with the actions of the brain-derived neurotrophic factor (BDNF), a protein critical in modulating neuroplasticity, glucose regulation, fat oxidation, and appetite regulation in adults. However, little research exists in youth. This study examined the associations between changes in diabetes risk factors and changes in BDNF levels after 6 months of exercise training in adolescents with obesity. The sample consisted of 202 postpubertal adolescents with obesity (70% females) aged 14–18 years who were randomized to 6 months of aerobic and/or resistance training or nonexercise control. All participants received a healthy eating plan designed to induce a 250/kcal deficit per day. Resting serum BDNF levels and diabetes risk factors, such as fasting glucose, insulin, homeostasis model assessment (HOMA-B—beta cell insulin secretory capacity) and (HOMA-IS—insulin sensitivity), and hemoglobin A1c (HbA1c), were measured after an overnight fast at baseline and 6 months. There were no significant intergroup differences on changes in BDNF or diabetes risk factors. In the exercise group, increases in BDNF were associated with reductions in fasting glucose ( = −6.57,  = 3.37, ) and increases in HOMA-B ( = 0.093,  = 0.03, ) after controlling for confounders. No associations were found between changes in diabetes risk factors and BDNF in controls. In conclusion, exercise-induced reductions in some diabetes risk factors were associated with increases in BDNF in adolescents with obesity, suggesting that exercise training may be an effective strategy to promote metabolic health and increases in BDNF, a protein favoring neuroplasticity. This trial is registered with ClinicalTrials.gov NCT00195858, September 12, 2005 (funded by the Canadian Institutes of Health Research).
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    Effects of the HEARTY exercise randomized controlled trial on eating behaviors in adolescents with obesity
    (World Obesity and The Obesity Society and John Wiley & Sons Ltd., 2022-06-06) Alberga, Angela S.; Edache, Iyoma Y.; Sigal, Ronald J.; von Ranson, Kristin M.; Russell-Mayhew, Shelly; Kenny, Glen P.; Doucette, Steve; Prud'homme, Denis; Hadjiyannakis, Stasia; Cameron, Jameason D.; Goldfield, Gary S.
    Background There are well-recognized benefits of behavioral interventions that include exercise for children and adolescents with obesity. However, such behavioral weight management programs may precipitate unintended consequences. It is unclear if different exercise modalities impact eating behaviors differently in youth with obesity. Objectives The purpose of this study was to examine the effects of aerobic, resistance, and combined aerobic and resistance exercise training on eating attitudes and behaviors (uncontrolled eating, restrained eating, emotional eating, external eating and food craving) among adolescents with overweight and obesity. Methods N = 304 (70% female) adolescents with overweight and obesity participated in the 6-month Healthy Eating Aerobic and Resistance Training in Youth (HEARTY) randomized controlled trial. All participants were inactive post-pubertal adolescents (15.6 ± 1.4 years) with a mean BMI = 34.6 ± 4.5 kg/m2. The Food Craving Inventory (food cravings), Dutch Eating Behavior Questionnaire (restrained eating, emotional eating, external eating), and the Three-Factor Eating Questionnaire (uncontrolled eating) were used to assess eating attitudes and behaviors. Results All exercise groups showed within-group decreases in external eating and food cravings. Participants randomized to the Combined training group and were more adherent showed the greatest improvements in eating behaviors and cravings. Conclusions A 6-month exercise intervention produced improvements in disordered eating behaviors and food cravings, but effects may be gender and modality-specific. Findings highlight the need to tailor exercise intervention to participant characteristics for the promotion of healthier eating and weight management outcomes in youth with obesity.
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    Exploring the Relationship Between Diabetes and Physical Activity Behaviours: Results from the Canadian Health Measures Survey (2007-2017)
    (2020-05-12) Booth, Jane; Sigal, Ronald J.; Rabi, Doreen M.; Goldfield, Gary S.; Sajobi, Tolulope T.
    Background: Diabetes Canada clinical practice guidelines recommend that individuals with type 2 diabetes accumulate a minimum of 150 minutes per week of moderate-to vigorous-intensity physical activity (MVPA) and reduce the amount of time spent sedentary. To our knowledge, there are no nationally-representative studies in Canada that have used objectively-measured physical activity data to assess the associations between physical activity and sociodemographic characteristics or cardiometabolic measures in people with type 2 diabetes. Thus, the objectives of this thesis were to (1) evaluate the associations between physical activity, sedentary time and cardiometabolic health and (2) evaluate the associations between physical activity, sedentary time and sociodemographic characteristics in adults with type 2 diabetes in a representative sample of the Canadian population. Methods: Cycles 1 to 5 of the Canadian Health Measures Survey (CHMS) were used. Participants with type 2 diabetes between 20 and 79 years of age who had at least four days of valid activity monitor wear were included. Means, medians and interquartile ranges were used to present estimates of physical activity and sedentary time. Physical activity was stratified by MVPA tertile and cardiometabolic mean values and/or proportions with 95% confidence intervals were compared. Median regression was used to evaluate the associations between 60-minute per week increment in total MVPA with hemoglobin A1c (A1C) and body mass index (BMI). Ordinal logistic regression was used to estimate the odds of achieving lower amounts of MVPA based on sociodemographic factors. Results: Only 21.5% of adults with type 2 diabetes met clinical practice guideline recommendations for physical activity. Higher amounts of MVPA and daily steps were associated with lower BMI, waist circumference and cardiometabolic risk composite score. Female sex, lower income, BMI ≥ 25 kg/m2, and being a current or former smoker were associated with lower levels of physical activity. Conclusions: Less than one quarter of adults with type 2 diabetes met physical activity recommendations. We identified important sociodemographic characteristics that were determinants of low levels of physical activity which should be considered by healthcare providers and policy-makers in order to inform and deliver effective physical activity interventions.
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    Polycystic Ovarian Syndrome: An Investigation of Non-Pharmacologic Management Strategies and Cardiometabolic Consequences
    (2021-05-12) Benham, Jamie L.; Sigal, Ronald J.; Corenblum, Bernard; Rabi, Doreen M.; Friedenreich, Christine M.
    Background: Preliminary evidence suggests exercise training may result in improved reproductive, anthropometric, cardiometabolic and psychosocial health in women with polycystic ovary syndrome (PCOS).Objective: To evaluate the effects of exercise training on reproductive, anthropometric, cardiometabolic, and sleep quality health measures in reproductive-aged women with PCOS.Methods: First, we performed a systematic review and meta-analysis of studies assessing the effects of exercise training on reproductive outcomes. Second, we performed a pilot randomized controlled trial evaluating the feasibility of conducting a larger trial evaluating reproductive, anthropometric, cardiometabolic, and sleep quality health measures. Feasibility outcomes included: participant recruitment, attrition, adherence to prescribed exercise and daily ovulation assessment.Results: The systematic review included 14 studies involving 617 women. Semi-quantitative analysis suggested exercise training may increase ovulation rates, menstrual regularity and pregnancy. In the trial, all recruitment methods were important as each recruited participant was not reached by the other methods. 47 participants were randomized: no-exercise control (n=17), high-intensity interval training (HIIT) (n=16), continuous aerobic exercise training (CAET) (n=14). Across all groups, attrition was 15%. Median exercise adherence was 68% (IQR 53%, 86%). Ovulation assessment adherence dropped from 87% (IQR 61%, 97%) in the first 3-months of the intervention to 65% (IQR 0%, 96%) in the final 3-months. 22/33 (66.7%) women ovulated during the intervention period with no between-group differences. Body mass index decreased for CAET compared with HIIT (-0.9 kg/m2, p=0.04) and control (-1.0 kg/m2, p=0.01). Mean waist circumference decreased significantly (-7.3 cm, -6.9 cm, -4.5 cm in HIIT, CAET and control) with no significant between-group differences. In HIIT compared with CAET, LDL-C decreased significantly (-0.33 mmol/L, p=0.03). In HIIT compared with control, HDL-C increased (0.18 mmol/L, p=0.04). 79% of participants reported poor sleep quality.Conclusions: While exercise training may improve anthropometric, reproductive and sleep quality health markers in women with PCOS, the effects of exercise training on reproductive health measures remain unclear. Feasibility challenges with exercise training and daily ovulation assessment adherence limited the ability to analyze the effect of exercise on ovulation. Further studies are needed to determine optimal exercise prescriptions for this population.
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    The Effects of Aerobic and Resistance Training on Health-Related Quality of Life in Individuals with Type 1 Diabetes: The T1-DARE and READI Trials
    (2018-10-26) Bastell, Kent Miles; Sigal, Ronald J.; Goldfield, Gary S.; Santana, Maria Jose
    Exercise can improve physical and psychological outcomes in many chronic diseases. However, effects of exercise training on health-related quality of life (HRQOL) in people with type 1 diabetes (T1DM) patients are not well known. We aimed to determine the effects of exercise on HRQOL in T1DM by analyzing data from two distinct studies, with parallel methodologies. In the T1-DARE trial (n=66) we assessed the effects of aerobic (n=17), resistance (n=17), combined training (n=16) and a non-exercise control group (n=16) on HRQOL in previously sedentary individuals with T1DM. In the READI trial (n=131), we examined whether there was an additive effect of resistance training (n=71) on HRQOL in already-aerobically active individuals with T1DM versus a non-resistance trained control group (n=60). All participants in both studies completed a pre-randomization run-in period to allow for optimization of insulin regimens, and assessment of adherence. Additionally, all participants in both studies completed a generic (SF-36) and disease-specific (DSQOLS) HRQOL questionnaire at baseline, 3 months and 6 months. In the T1 DARE trial, there were significant within-group increases in the SF-36 “Energy/Fatigue” subscale for the aerobic (⍙=6.9, p=0.04), resistance (⍙=9.3, p<0.01), and combined group (⍙=7.1, p=0.04). Significant between-group differences in change were observed for the aerobic (⍙=9.9, p=0.04), resistance (⍙=12.4, p=0.01), and combined groups (⍙=10.1, p=0.04) versus the control at 3 months only. For the “Physical Functioning” subscale, the resistance group had significant within-group increases at 3 months (⍙=8.7, p<0.01) and 6 months (⍙=7.7, p=0.02). For the DSQOLS, where lower score are indicative of higher functioning, there were significant within-group improvements in “Total Score” for the aerobic group at 6 months (⍙=-6.5, p=0.02) and for the “Daily Hassles” subscale at 6 months for both the aerobic (⍙=-8.9, p<0.001) and resistance (⍙=-6.7, p=0.01) groups. The READI Trial found significant within-group increases from all exercise groups in the “General Health” subscale at both 3 months (⍙= 4.3 95% CI, 1.1, 7.4, p = 0.008) and 6 months [⍙= 5.2, 95% CI, 2.2, 8.2, p < 0.001); with significant between-group changes at 6 months (⍙= 4.6, 95% CI, 0.1, 9.1, p = 0.046).
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    To Titrate or Not to Titrate: Factors influencing inpatient insulin management by residents and medical students
    (2019-07-10) Hinz, Laura Elizabeth; McLaughlin, Kevin J.; Sigal, Ronald J.; Oddone-Paolucci, Elizabeth
    The prevalence of diabetes continues to rise, making inpatient management of diabetes an increasingly relevant issue. In teaching hospitals such as those affiliated with the University of Calgary, inpatient management of diabetes is often the responsibility of learners including residents and medical students. Several studies have demonstrated that learners lack knowledge and confidence in inpatient insulin management. To improve the way learners are taught about inpatient insulin titration, we sought to elucidate what contextual factors and mechanisms of an educational intervention are more likely to improve glycemic outcomes, and what factors, both conscious and subconscious, learners consider when making decisions about insulin titration. To determine the contextual factors and mechanisms of successful diabetes educational interventions, we conducted a realist synthesis. After analysing 21 studies, we found that interventions that improve the insulin prescribing process are necessary but not sufficient to improve glycemic outcomes. In-person, group, prescriber-specific interventions with a reinforcing intervention are more likely to be successful. To study the factors that learners consider when titrating insulin, we conducted a mixed methods study using a case-based survey loosely modelled on script concordance testing. We found that medical students prescribed insulin with greater concordance with staff endocrinologists than residents, yet residents had more confidence than medical students in their prescribing practices. Overall, the residents prescribed larger doses of insulin. The residents were susceptible to the subconscious influence of the seniority of the nurse asking for an insulin dose, yet the medical students were not. Both groups of learners prescribed more insulin in the presence of ketones and less when the patient had hypoglycemia unawareness. Residents prescribed less insulin when patients had T2DM compared to T1DM and medical students prescribed more when the blood sugar crossed the 20mmol/L threshold. We concluded that patient, prescriber, and systems factors ultimately influenced insulin prescribing practices. Overall, we concluded that a successful educational intervention to improve inpatient glycemic control would likely need to address prescribing practices in a prescriber-specific fashion and be followed with a reinforcing intervention. We proposed that medical students and residents may need different teaching methods to address possibly different cognitive processing methods.