Development of a ParticipACTION App-Based Intervention for Improving Postsecondary Students' 24-Hour Movement Guideline Behaviors: Protocol for the Application of Intervention Mapping.

BACKGROUND: The Canadian 24-Hour Movement Guidelines for adults provide specific recommendations for levels of physical activity, sedentary behavior, and sleep (ie, the movement behaviors) required for optimal health. Performance of the movement behaviors is associated with improved mental well-being. However, most postsecondary students do not meet the movement behavior recommendations within the Canadian 24-Hour Movement Guidelines and experience increased stress and declining well-being, suggesting the need for an intervention targeting students' movement behaviors. OBJECTIVE: We aimed to develop and implement a theory-informed intervention intended to improve the movement behaviors and mental well-being of first-year postsecondary students. METHODS: The Intervention Mapping protocol was applied in the development and implementation of the intervention. Intervention Mapping entailed performing a needs assessment, determining the intervention outcomes, selecting theory- and evidence-based change methods and applications, preparing and producing intervention plans and materials, developing the implementation plan, and finally developing an evaluation plan. The Theoretical Domains Framework and the Behavior Change Wheel were also used in conjunction with the Intervention Mapping protocol to ensure a solid theoretical basis for the intervention. This protocol led to the development and implementation of a 6-week, theory-informed ParticipACTION app-based intervention aimed at helping first-year postsecondary students improve their movement behaviors and mental well-being. The developed app content provided students with information on each of the movement behaviors and behavioral strategies (ie, goal setting, action planning, monitoring, and coping planning). The use of Intervention Mapping allowed for the continuous involvement of various multidisciplinary partners and end users, ensuring that the intervention design and implementation was appropriate for the target audience. The feasibility, acceptability, and potential impact of the intervention will be examined in a subsequent proof-of-concept study at 2 Canadian university campuses. RESULTS: Participant recruitment occurred during September 2021, and the intervention was conducted from October to December 2021. The deadline for completion of the postintervention questionnaire by participants was mid-December 2021. The analysis of data examining the feasibility, acceptability, and potential impact of the intervention began in January 2022, with the publication of the proof-of-concept evaluation expected in 2023. CONCLUSIONS: Intervention Mapping with the Theoretical Domains Framework and Behavior Change Wheel was a useful approach to combine evidence and theoretical concepts to guide the design and implementation of a ParticipACTION app-based intervention targeting postsecondary students' movement behaviors and mental well-being. This process may serve as an example for other researchers developing multiple behavior change app-based interventions. Should the forthcoming evaluation demonstrate the intervention's acceptability, feasibility, and potential impact, the intervention may provide a scalable method of improving postsecondary students' movement behaviors and mental well-being. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR1-10.2196/39977.

An Evaluation of a Commercialized mHealth Intervention to Promote Physical Activity in the Workplace.

Background: UPnGO with ParticipACTION (UPnGO) was a commercialized 12-month workplace physical activity intervention, aimed at encouraging employees to sit less and move more at work. Its design took advantage of the ubiquitous nature of mobile fitness trackers and aimed to be implemented in any office-based workplace in Canada. The program was available at cost from June 2017 to April 2020. The objectives of this study are to evaluate the program and identify key lessons from the commercialization of UPnGO. Methods: Using a quasi-experimental design over 3 time points: baseline, 6 months, 12 months, five evaluation indicators were measured as guided by the RE-AIM framework. Reach was defined as the number and percentage of employees who registered for UPnGO and the number and percentage of sedentary participants registered. Effectiveness was assessed through average daily step count. Adoption was determined by workplace champion and senior leadership responses to the off-platform survey. Implementation was assessed as the percentage of participants who engaged with specific program elements at the 3-evaluation time points. Maintenance was assessed by the number of companies who renewed their contracts for UPnGO. Results: Reach across 17 organizations, 1980 employees participated in UPnGO, with 27% of participants identified as sedentary at baseline. Effectiveness Daily step count declined from 7,116 ± 3,558 steps at baseline to 6,969 ± 6,702 (p = <0.001) at 12 months. Adoption Workplace champion and senior leadership engagement declined from 189 to 21 and 106 to 5 from baseline to 12 months, respectively. Maintenance Two companies renewed their contracts beyond the first year. Conclusions: The commercialization of UPnGO was an ambitious initiative that met with limited success; however, some key lessons can be generated from the attempt. The workplace remains an important environment for PA interventions but effective mHealth PA programs may be difficult to implement and sustain long-term.

Low-frequency exercise training improves cardiovascular fitness and strength during treatment for breast cancer: a single-arm intervention study.

Aerobic and resistance exercise during and after cancer treatment are important for health-related outcomes, however treatment-specific barriers may inhibit adherence. We explored the effect of lower-frequency exercise training on fitness, body composition, and metabolic markers (i.e. glucose and lipids) in a group of recently diagnosed breast cancer patients. Fifty-two females ≥ 18 years with stage I-IIIB breast cancer were instructed to attend 2 cardiovascular and strength training sessions/week over 12 weeks, but program length was expanded as needed to accommodate missed sessions. Pre- and post-intervention, we measured: (1) cardiovascular fitness, (2) isometric strength, (3) body composition (dual-energy X-ray absorptiometry), and (4) fasting glucose, insulin, c-peptide, and lipids. Pre-intervention, participants were 53 ± 10 years old (mean ± SD) and overweight (BMI: 27.5 ± 5.4 kg m-2, 40.1 ± 6.5% body fat). Forty participants completed the program over a median 20 weeks (range: 13-32 weeks, median frequency: 1.2 sessions/week), over which predicted VO2peak improved by 7% (2.2[0.1-4.4] mL/kg/min) (delta[95% CI]), and strength increased by 7-9% (right arm: 2.3[0.1-4.5] N m; right leg: 7.9[2.1-13.7] N m; left leg: 7.8[1.9-13.7] N m). Body composition and metabolic markers were unchanged. An exercise frequency of 1.2 sessions/week stimulated significant improvements in fitness, and may represent a practical target for patients during active treatment.

Strange Days: Adult Physical Activity and Mental Health in the First Two Months of the COVID-19 Pandemic.

Background: In addition to its physical health benefits, physical activity is increasingly recognized as a means to support mental health. Regular moderate-to-vigorous physical activity (MVPA) is associated with improved mental well-being, reduced likelihood of developing mental illness, and improved symptom management. Despite these benefits, most people fail to achieve minimum recommended levels of MVPA. Population levels of physical activity have further declined since the onset of the COVID-19 pandemic and implementation of public health measures (e.g., shelter-in-place protocols). The potential impact of this decline on mental heath outcomes warrants ongoing investigation. Purpose: To investigate associations between changes in MVPA and mental health (depressive symptoms, anxiety symptoms, and life satisfaction) in adults impacted by the COVID-19 pandemic. Method: Research followed a cross-sectional design. English-speaking adults were invited to complete an online questionnaire. MVPA was assessed retrospectively (before COVID-19) and currently (during COVID-19) with the International Physical Activity Questionnaire. Mental health was assessed with the Patient Health Questionnaire, 9-Item (PHQ-9), the Generalized Anxiety Disorder, 7-Item (GAD-7), and the Satisfaction with Life Scale (SWLS). Regression was used to assess relationships between MVPA and mental health. ANOVA with follow-up tests examined whether participants who differed in mental health status (e.g., no symptoms vs. severe symptoms) differed in their change in MVPA. T-tests were used to examine differences in mental health symptomatology between participants who were sufficiently (i.e., achieving MVPA guidelines of ≥ 150 min/week) vs. insufficiently active. Results: Prior to COVID-19, 68.2% of participants were classified as being sufficiently active, vs. 60.6% during COVID-19. The majority of participants reported experiencing some level of depressive symptoms (62.0%) or anxiety symptoms (53.7%). After controlling for covariates, changes in MVPA accounted for significant variability in the PHQ-9 (7.7%), GAD-7 (2.5%), and SWLS (1.5 %). Participants with clinically significant mental health symptomatology reported greater declines in MVPA than those who reported no symptoms. Conversely, participants who were sufficiently active during COVID-19 reported significantly lower depression and anxiety, and higher life satisfaction. Conclusion: Participants who experienced the greatest declines in MVPA reported relatively greater psychological distress and lower life satisfaction. While preliminary, these findings suggest the importance of maintaining and promoting physical activity during a period of pandemic.

The Energy to Smoke: Examining the Longitudinal Association between Beverage Consumption and Smoking and Vaping Behaviours among Youth in the COMPASS Study.

This study examined the longitudinal association between changes in sugar-sweetened and/or caffeinated beverage consumption and smoking/vaping behaviour among Canadian adolescents. Using longitudinal data from the COMPASS study (2015/16 to 2017/18), four models were developed to investigate whether beverage consumption explained variability in smoking and vaping behaviour in adolescence: (1) smoking initiation, (2) vaping initiation, (3) current smoking status, and (4) current vaping status. Models were adjusted for demographic factors. Multinomial logit models were used for model 1, 2, and 3. A binary logistic regression model was used for model 4. An association between change in frequency of beverage consumption and smoking/vaping behaviour was identified in all models. A one-day increase in beverage consumption was associated with smoking initiation (OR = 1.38, 95% CI: 1.25, 1.51), vaping initiation (OR = 1.23, 95% CI: 1.14, 1.32), identifying as a current smoker (OR = 1.17, 95% CI: 1.01, 1.35), and currently vaping (OR = 1.08, 95% CI: 1.04, 1.11). Change in high-energy drink consumption was the best predictor of smoking behaviours and vaping initiation but not current vaping status. Given the health consequences of smoking and vaping and their association with high-energy drink and coffee consumption, policy initiatives to prevent smoking/vaping initiation, and to limit youth access to these beverages, warrant consideration.

The University of British Columbia healthy beverage initiative: changing the beverage landscape on a large post-secondary campus.

OBJECTIVE: Environmental interventions are more effective at changing nutrition behaviour than educational campaigns alone. As part of their health promotion efforts, the University of British Columbia (UBC) developed the Healthy Beverage Initiative (HBI) to ultimately reduce the consumption of sugar-sweetened beverages (SSB) on campus. We describe the development, implementation, preliminary evaluation and future of the HBI. DESIGN: Naturalistic observation of environmental changes to induce behaviour change. SETTING: Large urban research university campus. PARTICIPANTS: University community members and campus visitors. RESULTS: Three main activities have been implemented since the initiation of the UBC HBI: renegotiation of the cold beverage agreement, a media campaign to promote tap water consumption and the removal of SSB from select retail locations on campus (residence dining hall). No significant loss of revenue was observed following the removal of SSB from a residence dining hall compared with similar locations. Compensatory purchasing behaviour of SSB was not observed at the closest retail locations where they were still available. After the removal of SSB, ~75% of survey respondents were not aware that the beverages had been removed. CONCLUSIONS: The implementation of the HBI has met little resistance from the UBC community. The removal of SSB from residence dining locations did not result in any significant revenue loss or compensatory purchasing behaviour. This suggests that environmental intervention initiatives appear to be a viable option that may reduce SSB consumption on post-secondary campuses.

The use of the behaviour change wheel in the development of ParticipACTION's physical activity app.

The purpose of this study was to provide a detailed and systematic outline of how a theoretical behaviour change framework was applied in the development of ParticipACTION's app to support a more active Canada. The app development process was guided by the Behaviour Change Wheel (BCW) framework, a theoretically-based approach for intervention development, in collaboration with the commercial app industry. Specifically, a behavioural diagnosis was used to understand what needs to change for the targeted behaviour to occur. Current literature, along with a series of surveys, and market research informed app development. Additionally, a validated app behaviour change scale, was consulted throughout development to help ensure app features maximized behaviour change potential. The behavioural diagnosis revealed that the app needed to target individuals' physical and psychological capabilities, physical and social opportunities, and reflective and automatic motivations in order to increase physical activity levels. To accomplish this, 6 of a possible 9 intervention functions and 2 of 7 policy categories were selected from the BCW to be included in the app. Goals and planning, feedback and monitoring, behaviour identification, action planning and knowledge shaping were selected as the main behaviour change techniques for the app. Collaboration with a mobile app development firm helped to embed the selected behaviour change techniques, policy categories, intervention functions, and sources of behaviour within the app. Using a systematic approach, this study used the BCW to ensure the health promotion app was theoretically informed. Future research will evaluate its effectiveness in increasing the physical activity of Canadians.

Don't Walk So Close to Me: Physical Distancing and Adult Physical Activity in Canada.

Background: In response to the COVID-19 pandemic, physical distancing measures have been implemented globally. Canadians have been instructed to stay at home, which has likely resulted in significant changes in their physical activity. Using data from a national physical activity tracking app (PAC app), we aimed to determine device-measured physical activity levels immediately prior to and following the implementation of physical distancing measures in Canada to provide evidence for the development of physical activity recommendations for future pandemics or second wave infections. Methods: Demographic and physical activity data were extracted from the ParticipACTION app (PAC app), using a 10-week (10 February to 19 April 2020) quasi-experimental design to determine changes in physical activity 4 weeks pre-pandemic and 6 weeks post-pandemic declaration. Weekly physical activity levels were monitored through wearable fitness trackers and health apps linked to the PAC app, to record moderate-to-vigorous physical activity (MVPA), light physical activity (LPA), and steps. Repeated measure ANOVA was used to determine changes over time (mean ± SE). Findings: A total of 2,338 Canadians who were mostly 35-44 years old (26.6%) and female (90.2%) were included in the analysis. MVPA, LPA, and steps significantly declined immediately following the declaration of the pandemic (MVPA: pre-pandemic: 194.2 ± 5.2 min, post-pandemic: 176.7 ± 5.0 min, p < 0.001; LPA: pre-pandemic: 1,000.5 ± 17.0 min, post-pandemic: 874.1 ± 15.6 min, p < 0.001; steps: pre-pandemic: 48,625 ± 745 steps, post-pandemic: 43,395 ± 705 steps, p < 0.001). However, 6 weeks following pandemic declaration, MVPA (week 6: 204.4 ± 5.4 min, p = 0.498) had returned to pre-pandemic levels. LPA (week 6: 732.0 ± 14.3 min, p = < 0.001) and steps (week 6: 41,946 ± 763, p < 0.001) remained significantly lower than pre-pandemic levels at week 6. Interpretation: Although MVPA returned to pre-pandemic levels, significant and sustained declines in incidental LPA and steps were observed. Attenuating the loss of incidental physical activity should be a public health priority in response to future pandemics or a second wave of a COVID-19 infection, as it may have significant long-term implications for the physical and mental health of Canadians.

"One stroke, with twenty-two people": exploring prostate cancer survivors' participation in dragon boating.

Purpose: This study qualitatively explores prostate cancer survivors' experience in joining a dragon boating team and its possible impact on their wellbeing.Design: Qualitative data analysis.Sample: Eleven prostate cancer survivors from a dragon boat team.Methods: Semi-structured interviews and thematic analysis.Findings: The findings support physical benefits of dragon boating, however, the positive impact on the men's psychosocial wellbeing was more salient. Participation in dragon boating was important for establishing a social support system and positively reframing their cancer experience.Practice Implications: Dragon boating is a novel health promotion strategy for men with PC. Seeking to replicate the positive characteristics of dragon boating in the design of future physical activity interventions should be explored.

Facilitators and barriers to participation in lifestyle modification for men with prostate cancer: A scoping review.

PURPOSE: Diet and physical activity changes have been shown to improve quality of life and health outcomes for prostate cancer (PC) survivors; however, few survivors make lifestyle changes. We aimed to identify PC-specific facilitators and barriers to dietary and physical activity changes and participation in survivorship-based lifestyle management programmes. METHODS: A scoping review investigating facilitators and barriers of PC survivor's participation in lifestyle management programmes was conducted in June 2018. A total of 454 studies were identified, 45 studies were assessed in full, and 16 were included in the scoping review. RESULTS: Barriers to lifestyle change included perceived lack of evidence for lifestyle guidelines, treatment side effects, perception of change as unnecessary, time pressure and age. Facilitators for lifestyle change included advice from health professionals, support systems (family and peer), diagnosis as a time for change, lifestyle as a coping strategy to manage side effects and improve well-being. CONCLUSIONS: Health professionals, peers and family have a significant role in lifestyle management for PC survivors to facilitate engagement. Specific and clear messaging of the benefits of lifestyle management is warranted. Treatment-related side effects, time pressure, current health perception and age should be considered when developing lifestyle management programmes for PC survivors.

Nutrition and Cancer Prevention: Why is the Evidence Lost in Translation?

With the high burden of cancer worldwide, primary prevention has been identified as a key cancer control strategy to reduce this burden. Diet and nutrition are important modifiable factors that may alter the risk of developing cancer, because several dietary components including alcohol consumption, fruit and vegetable intake, and dietary fiber have been shown to significantly impact cancer risk. Consequently, a number of organizations have developed cancer prevention guidelines that highlight the importance of nutrition (and related factors including body size and physical activity) to reduce the risk of cancer. However, there are barriers to the uptake of these guidelines, particularly with respect to diet and nutrition including awareness, communication, and other factors that influence eating behavior. Improved knowledge translation (KT) of recommendations may help facilitate uptake. The purposes of this narrative review are: 1) to examine issues and challenges related to KT of diet and nutrition evidence in the context of cancer prevention, including public awareness and attitudes towards cancer prevention, engagement in cancer prevention strategies, and effects of KT on diet-cancer preventive behaviors; 2) to discuss examples of effective and ineffective KT of diet and nutrition evidence; and 3) to provide recommendations for improving KT to help move the field of diet, nutrition, and cancer prevention forward. Evidence shows that adherence to nutrition recommendations for cancer prevention significantly reduces the risk of cancer; however, engagement in nutrition-based preventative behaviors is low. Skepticism and confusion around evidence linking diet and nutrition with cancer may arise, in part, through ineffective media KT; the primary source of health information for many people. Simple, tailored, targeted KT communication strategies aimed at increasing the general public's awareness, attitudes, and engagement in cancer preventive behavior should be emphasized to encourage cancer control.

Glutamate increases glucose uptake in L6 myotubes in a concentration- and time-dependent manner that is mediated by AMPK.

Various in vivo studies have investigated the insulin response that is elicited when glutamate is elevated in circulation or in a given tissue; fewer studies have investigated the effects of glutamate on glucose uptake and handling. Glutamate ingestion in humans can attenuate rises in blood glucose following a carbohydrate load in the absence of increases in serum insulin concentrations. However, the underlying mechanisms have yet to be investigated. To elucidate the effects of glutamate on glucose handling in skeletal muscle tissue, differentiated rat L6 myocytes were treated with glutamate, and glucose uptake was assessed with the use of 2-[3H]-deoxy-d-glucose ([3H]-2-DG). Cells treated with 2 mmol/L glutamate experienced the greatest increase in [3H]-2-DG uptake relative to the control condition (177% ± 2% of control, P < 0.001) and the uptake was similar to that of metformin (184% ± 4%, P < 0.001). In line with these findings, differentiated glucose transporter 4 (GLUT4)-overexpressing myotubes treated with 2 mmol/L glutamate displayed significantly increased GLUT4 translocation when compared with the control condition (159% ± 8% of control, P < 0.001) and to an extent similar to that of insulin and metformin (181% ± 7% and 159% ± 12%, respectively). An AMP-activated protein kinase (AMPK) inhibitor (Compound C) abolished the glutamate-stimulated glucose uptake (98% ± 12% of control), and Western blotting revealed significantly elevated AMPK phosphorylation (278% ± 17% of control, P < 0.001) by glutamate. Our findings suggest that when muscle cells are exposed to increased glutamate concentrations, glucose uptake into these cells is augmented through AMPK activation, through mechanisms distinct from those of insulin and leucine.

Glucose metabolism during the acute prostate cancer treatment trajectory: The influence of age and obesity.

BACKGROUND & AIMS: Obesity and age, key risk factors for aggressive prostate cancer, are associated with insulin resistance. Glucose-related parameters in patients with aggressive prostate cancer were compared with 2 reference groups: men of similar age and body mass index (BMI) without cancer, and healthy young men. Acute changes in these parameters following radiation treatment were also evaluated. METHODS: Nine patients with aggressive prostate cancer underwent metabolic assessments prior to treatment (baseline), 7 and 33 weeks post-baseline (post-treatment initiation). Baseline measures were compared with the 2 reference groups. Evaluations included: 1) fasting and oral glucose tolerance test (OGTT) blood samples for glucose, C-peptide, and insulin, 2) fasting blood samples for triglycerides, cholesterols, leptin, adiponectin, IL-6, and TNF-α, 3) body composition, 4) nutrition, and 5) physical activity. RESULTS: At baseline, patients had normal fasting glucose concentrations (<5.6 mM; 4.9 ± 1.2 mM) but impaired 2-h OGTT glucose concentrations (>7.8 mM; 8.7 ± 2.9 mM). Both reference groups had normal fasting (matched males: 4.2 ± 0.5 mM; young males: 3.7 ± 0.4 mM) and 2-h OGTT glucose concentrations (matched males: 5.6 ± 1.8 mM; young males: 3.1 ± 0.1 mM) that were significantly lower than patient values. During the OGTT, patients had higher insulin (120 min) and C-peptide (45, 60, 90, 120 min) concentrations compared to the matched males. At 7 weeks, 2-h OGTT glucose concentrations in patients improved to healthy ranges without changes in insulin, C-peptide, IGF-1, IGFBP-3 or other metabolic parameters. CONCLUSIONS: At baseline patients with aggressive prostate cancer demonstrated impaired glucose tolerance compared with men of similar age and body size. Following treatment, glucose tolerance improved in the absence of changes in expected modifiers of glucose metabolism. These improvements may be related to treatment.

Elevated C-Peptides, Abdominal Obesity, and Abnormal Adipokine Profile are Associated With Higher Gleason Scores in Prostate Cancer.

BACKGROUND: Prostate cancer development is associated with numerous lifestyle factors (i.e., physical activity, nutrition intake) and metabolic perturbations. These factors have been studied independently; here, we used an integrative approach to characterize these lifestyle and metabolic parameters in men undergoing diagnostic prostate biopsies. METHODS: We prospectively evaluated 51 consecutive men for body composition, metabolic factors including glucose- and lipid-related measures, as well as lifestyle factors prior to prostate biopsy. Evaluations were performed in a blinded manner and were subsequently related to biopsy outcomes for: (i) presence or absence of cancer; and (ii) where cancer was present, Gleason score. RESULTS: Serum C-peptide concentrations were significantly greater in participants with Gleason scores ≥4 + 3 (2.8 ± 1.1 ng/ml) compared to those with Gleason 3 + 3 (1.4 ± 0.6 ng/ml) or Gleason 3 + 4 (1.3 ± 0.8 ng/ml, P = 0.002), suggesting greater insulin secretion despite lack of differences in fasting glucose concentrations. Central adiposity, measured by waist circumference, was significantly greater in participants with Gleason ≥4 + 3 (110.1 ± 7.4 cm) compared to those with Gleason 3 + 4 (102.0 ± 9.5 cm, P = 0.028). Men with Gleason ≥4 + 3 also had significantly greater leptin concentrations than those with lower Gleason scores (Gleason ≥4 + 3: 15.6 ± 3.3 ng/ml vs. Gleason 3 + 4: 8.1 ± 8.1 ng/ml, P < 0.05) and leptin:adiponectin ratio (Gleason ≥4 + 3: 9.7 ± 6.1 AU, Gleason 3 + 4: 2.9 ± 3.2, Gleason 3 + 3: 2.4 ± 2.1 AU, P = 0.013). CONCLUSIONS: We profiled a cluster of obesity-related metabolic perturbations (C-peptide, central adiposity, leptin, and leptin:adiponectin ratios) which may associate with more aggressive prostate cancer histology. Prostate 77:211-221, 2017. © 2016 Wiley Periodicals, Inc.

The role of dietary fat throughout the prostate cancer trajectory.

Prostate cancer is the second most common cancer diagnosed world-wide; however, patients demonstrate exceptionally high survival rates. Many lifestyle factors, including obesity and diet, are considered risk factors for advanced prostate cancer. Dietary fat is a fundamental contributor to obesity and may be specifically important for prostate cancer patients. Prostate cancer treatment can result in changes in body composition, affecting quality of life for survivors by increasing the risk of co-morbidities, like cardiovascular disease and diabetes. We aim to examine dietary fat throughout the prostate cancer treatment trajectory, including risk, cancer development and survivorship. Focusing on one specific nutrient throughout the prostate cancer trajectory provides a unique perspective of dietary fat in prostate cancer and the mechanisms that may exacerbate prostate cancer risk, progression and recurrence. Through this approach, we noted that high intake of dietary fat, especially, high intake of animal and saturated fats, may be associated with increased prostate cancer risk. In contrast, a low-fat diet, specifically low in saturated fat, may be beneficial for prostate cancer survivors by reducing tumor angiogenesis and cancer recurrence. The insulin-like growth factor (IGF)/Akt signaling pathway appears to be the key pathway moderating dietary fat intake and prostate cancer development and progression.

A comprehensive metabolic evaluation reveals impaired glucose metabolism and dyslipidemia in breast cancer patients early in the disease trajectory.

BACKGROUND & AIMS: Weight gain in breast cancer patients during treatment is prevalent; the metabolic implications of this weight gain are poorly understood. We aimed to characterize glucose metabolism in breast cancer patients near the initiation of chemotherapy. METHODS: Stage I-II breast cancer patients (n = 8) were evaluated near the initiation of chemotherapy and compared with a group of age- and body mass index-matched, as well as a group of young healthy, non-malignant females. Fasting blood samples (analyzed for lipids and cytokines) were taken and an oral glucose tolerance test was performed. Body composition, waist circumference, diet, cardiovascular fitness and muscle strength were evaluated. RESULTS: Breast cancer patients were abdominally obese (mean ± SD: 94.6 ± 14.0 cm), overweight (28.8 ± 6.0 kg/m(2)) and dyslipidemic (triacylglycerides: 1.84 ± 1.17 mM; high-density lipoprotein cholesterol: 1.08 ± 0.23 mM). Compared to non-malignant matched females, fasting glucose and insulin concentrations were similar but fasting c-peptide was greater in patients (2.6 ± 1.2 ng/mL vs. 1.9 ± 0.8 ng/mL, p = 0.005). Glucose was elevated to a greater extent in patients during the oral glucose tolerance test compared with all non-malignant females. During the glucose tolerance test, c-peptide, but not insulin, remained elevated in patients compared with all non-malignant females. No differences in body composition, serum cytokines, nutrition or exercise capacity between patients and matched, non-malignant females emerged. CONCLUSIONS: Breast cancer patients present with unhealthy metabolic features early in the disease trajectory. Future investigations need to examine the underlying mechanisms and the potential longitudinal changes following chemotherapy.

Glutamate supplementation is associated with improved glucose metabolism following carbohydrate ingestion in healthy males.

Glutamate is linked to the glycolytic process, particularly when co-ingested with carbohydrate, but its effects on glucose metabolism are poorly characterised. The present study aimed to (1) specifically examine the effects of carbohydrate administration on circulating glutamate concentrations and (2) investigate the effect of increased glutamate availability, independent of carbohydrate ingestion, on glucose metabolism. A total of nine participants underwent four trials: (1) glutamate supplement+carbohydrate drink (GLU+CHO); (2) glutamate supplement+placebo drink (GLU); (3) placebo supplement+carbohydrate drink (CHO); (4) placebo supplement+placebo drink (CON). Following a fasting blood sample, participants ingested monosodium L-glutamate (MSG; 150 mg/kg body weight) or placebo capsules at each trial followed by a 75 g carbohydrate or a non-energy placebo drink 30 min later. Blood samples were taken at 0, 10, 20, 30, 40, 50, 60, 75, 90, 105 and 120 min. Plasma glutamate concentrations were significantly elevated relative to baseline during the GLU (approximately 10-fold) and GLU+CHO trials (approximately 6-fold). The glucose response to a carbohydrate load was blunted when glutamate was increased in the circulation (peak serum glucose: 5.50 (SE 0.54) mmol/l during the GLU+CHO trial v. 7.69 (SE 0.53) mmol/l during the CHO trial, P< 0.05). On average, c-peptide results revealed that insulin secretion did not differ between the GLU+CHO and CHO trials; however, four participants demonstrated increased insulin secretion during the GLU+CHO trial and five participants demonstrated decreased insulin secretion under the same conditions. In conclusion, when administration is staggered, MSG and carbohydrate supplementation can be used to manipulate plasma glutamate; however, future studies should control for this dichotomous insulin response.

Accelerated muscle and adipose tissue loss may predict survival in pancreatic cancer patients: the relationship with diabetes and anaemia.

Weight loss leading to cachexia is associated with poor treatment response and reduced survival in pancreatic cancer patients. We aim to identify indicators that allow for early detection that will advance our understanding of cachexia and will support targeted anti-cachexia therapies. A total of fifty pancreatic cancer patients were analysed for skeletal muscle and visceral adipose tissue (VAT) changes using computed tomography (CT) scans. These changes were related to physical characteristics, secondary disease states and treatment parameters. Overall, patients lost 1.72 (SD 3.29) kg of muscle and 1.04 (SD 1.08) kg of VAT during the disease trajectory (413 (SD 213) d). After sorting patients into tertiles by rate of VAT and muscle loss, patients losing VAT at > -0.40 kg/100 d had poorer survival outcomes compared with patients with < -0.10 kg/100 d of VAT loss (P= 0.020). Patients presenting with diabetes at diagnosis demonstrated significantly more and accelerated VAT loss compared with non-diabetic patients. In contrast, patients who were anaemic at the first CT scan lost significantly more muscle tissue and at accelerated rates compared with non-anaemic patients. Accelerated rates of VAT loss are associated with reduced survival. Identifying associated features of cachexia, such as diabetes and anaemia, is essential for the early detection of cachexia and may facilitate the attenuation of complications associated with cachexia.

A critical evaluation of body composition modalities used to assess adipose and skeletal muscle tissue in cancer.

The majority of cancer patients experience some form of body composition change during the disease trajectory. For example, breast cancer patients undergoing chemotherapy and prostate cancer patients undergoing androgen deprivation therapy gain fat and lose skeletal muscle, which are associated with increased risk of cancer recurrence and clinical comorbidities. In contrast, advanced cancer patients, such as lung and colorectal cancer patients, experience symptoms of cancer cachexia (accelerated loss of skeletal muscle with or without adipose tissue loss), which are associated with decreased treatment response and poorer survival rates in advanced cancers. The heterogeneity of body composition features and their diverse implications across different cancer populations supports the need for accurate quantification of muscle and adipose tissue. Use of appropriate body composition modalities will facilitate an understanding of the complex relationship between body composition characteristics and clinical outcomes. This will ultimately support the development and evaluation of future therapeutic interventions that aim to counter muscle loss and fat gain in cancer populations. Despite the various metabolic complications that may confound the accurate body composition measurement in cancer patients (i.e., dehydration may confound lean tissue measurement), there are no guidelines for selecting the most appropriate modalities to make these measurements. In this review we outline specific considerations for choosing the most optimal approaches of lean and adipose tissue measurements among different cancer populations. Anthropometric measures, bioelectrical impedance analysis, air displacement plethysmography, dual-energy X-ray absorptiometry, computed tomography, and magnetic resonance imaging will be discussed.