Scientists and scientific journals should adhere to ethical standards for the use and reporting of data from Indigenous people.

Internationally, governments and scientists are bound by legal and treaty rights when working with Indigenous nations. These rights include the right of Indigenous people to control the conduct of science with Indigenous nations. Unfortunately, in some cases, individual scientists and scientific teams working with biological and genetic data collected from Indigenous people have not respected these international rights. Here, we argue that the scientific community should understand and acknowledge the historical harms experienced by Indigenous people under the veil of scientific progress (truth) and implement existing standards for ethical conduct of research and sovereign control of data collected within Indigenous communities (reconciliation). Specifically, we outline the rationale for why scientists, scientific journals and research integrity and institutional review boards/ethics committees should adopt, and be held accountable for upholding, current international standards of Indigenous data sovereignty and ethical use of Indigenous biological samples.

Early life adversity and obesity risk in adolescence: a 9-year population-based prospective cohort study.

BACKGROUND: There are few prospective studies of factors that mediate the association between exposure to adverse childhood experiences (ACEs) and obesity in adolescence. Our aim was to address this limitation. METHODS: We used prospective data from the Growing up in Ireland cohort study, with measurements at 9, 13, and 18 years old. The exposures were 14 adverse experiences before age 9. The main outcome was body mass index (BMI) at 18 years. Mediators were daily activity, diet quality, self-image and behavioural difficulties at 13 years. RESULTS: Among the 4561 adolescents in the final cohort, 77.2% experienced any adversity, 50.5% were female and 26.7% were overweight/obese at 18 years. BMI Z was higher at ages 9 (0.54 vs 0.43, p < 0.05, 95% CI of difference: -0.22, -0.01) and 13 years (0.50 vs 0.35, p < 0.05, 95% CI of difference: -0.25, -0.06), in those exposed to an ACE, compared to those unexposed. Structural equation models revealed that behavioural difficulties (ß = 0.01; 95% CI: 0.007-0.018, p < 0.001) and self-concept (ß = 0.0027; 95% CI: 0.0004-0.0050, p = 0.026) indirectly mediate the association between exposure to ACEs and BMI at 18 years. CONCLUSIONS: The association between ACEs and BMI in adolescence is mediated by behavioural difficulties and self-concept. IMPACT: In a previous study, we found modest associations between exposure to a range of adverse childhood experiences and weight gain at 13 years of age. The strength of the association between adverse childhood experiences and weight gain was lower at 18 years of age compared to the association observed at 13 years and was no longer significant after controlling for confounding and including possible mediators. The association between adverse childhood experiences and BMI in adolescence is indirectly mediated by behavioural difficulties and self-concept.

Ensuring Indigenous co-leadership in health research: a Can-SOLVE CKD case example.

BACKGROUND: Indigenous people are insightful and informed about their own health and wellness, yet their visions, strengths and knowledge are rarely incorporated into health research. This can lead to subpar engagement or irrelevant research practices, which exacerbates the existing health inequities Indigenous people experience compared to the non-Indigenous population. Data consistently underscores the importance of Indigenous self-determination in research as a means to address health inequities. However, there are few formal methods to support this goal within the existing research context, which is dominated by Western perspectives. MAIN TEXT: Canadians Seeking Solutions and Innovations to Overcome Chronic Kidney Disease (Can-SOLVE CKD) is a patient-oriented research network in Canada that recognizes the need to create the space to facilitate Indigenous self-determination in research. Indigenous members of the network therefore created and evolved a unique group, called the Indigenous Peoples' Engagement and Research Council (IPERC). IPERC plays a critical role in informing Can-SOLVE CKD research priorities, as well as creating tools to support Indigenous-specific research and engagement. This approach ensures that Indigenous voices and knowledge are critical threads within the fabric of the network's operations and research projects. Here, we describe the methods taken to create a council such as IPERC, and provide examples of initiatives by the council that aim to increase Indigenous representation, participation and partnership in research. We share lessons learned on what factors contribute to the success of IPERC, which could be valuable for other organizations interested in creating Indigenous-led research councils. CONCLUSION: Indigenous self-determination in research is critical for addressing health inequities. Here, we present a unique model, led by a council of diverse Indigenous people, which could help reduce health equities and lead to a better era of research for everyone.

Multi-use physical activity trails in an urban setting and cardiovascular disease: a difference-in-differences analysis of a natural experiment in Winnipeg, Manitoba, Canada.

OBJECTIVE: To determine if expansion of multi-use physical activity trails in an urban centre is associated with reduced rates of cardiovascular disease (CVD). METHODS: This was a natural experiment with a difference in differences analysis using administrative health records and trail-based cycling data in Winnipeg, Canada. Prior to the intervention, each year, 314,595 (IQR: 309,044 to 319,860) persons over 30 years without CVD were in the comparison group and 37,901 residents (IQR: 37,213 to 38,488) were in the intervention group. Following the intervention, each year, 303,853 (IQR: 302,843 to 304,465) persons were in the comparison group and 35,778 (IQR: 35,551 to 36,053) in the intervention group. The natural experiment was the construction of four multi-use trails, 4-7 km in length, between 2010 and 2012. Intervention and comparison areas were based on buffers of 400 m, 800 m and 1200 m from a new multi-use trail. Bicycle counts were obtained from electromagnetic counters embedded in the trail. The primary outcome was a composite of incident CVD events: CVD-related mortality, ischemic heart disease, cerebrovascular events and congestive heart failure. The secondary outcome was a composite of incident CVD risk factors: hypertension, diabetes and dyslipidemia. RESULTS: Between 2014 and 2018, 1,681,125 cyclists were recorded on the trails, which varied ~ 2.0-fold across the four trails (2358 vs 4264 counts/week in summer months). Between 2000 and 2018, there were 82,632 CVD events and 201,058 CVD risk events. In propensity score matched Poisson regression models, the incident rate ratio (IRR) was 1.06 (95% CI: 0.90 to 1.24) for CVD events and 0.95 (95%CI: 0.88 to 1.02) for CVD risk factors for areas within 400 m of a trail, relative to comparison areas. Sensitivity analyses indicated this effect was greatest among households adjacent to the trail with highest cycling counts (IRR = 0.85; 95% CI: 0.75 to 0.96). CONCLUSIONS: The addition of multi-use trails was not associated with differences in CVD events or CVD risk factors, however the differences in CVD risk may depend on the level of trail use. TRIAL REGISTRATION: Trial registration number: NCT04057417 .

The essential conditions needed to implement the Indigenous Youth Mentorship Program: a focused ethnography.

BACKGROUND: The Indigenous Youth Mentorship Program (IYMP) is a 20-week communal, relationship-based afterschool healthy living program for Indigenous youth in Canada. IYMP embraces the Anishnaabe/Nehiyawak concepts of Mino-Bimaadiziwin/miyo-pimâtisiwin ("living in a good way") via its core components of physical activities/games, healthy snacks, and relationship-building. A strength of IYMP is that it values autonomy, adaptability, and the school community context. However, this presents challenges when evaluating its implementation, given that traditional implementation science methods tend to oversimplify the process. In response, essential conditions for the implementation of school-based healthy living programs across diverse contexts have been developed. The purpose of this research was to understand the applicability of these essential conditions within the context of IYMP. METHODS: 15 participants (n = 10 Young Adult Health Leaders; n = 5 coordinators) with experience implementing IYMP in the provinces of Alberta, Saskatchewan, Manitoba, and Quebec were purposefully sampled. Focused ethnography was the guiding method and one-on-one semi-structured interviews were used as the data generation strategy. The purpose of the interviews was to understand what conditions are needed to implement IYMP. The interview guide was based on previously established essential conditions developed by the research team. Interviews were audio-recorded and transcribed, and content analysis was used to identify patterns in the data. RESULTS: The overarching theme that emerged from the interviews was the applicability of the essential conditions when implementing IYMP. Participants felt the eight core conditions (students as change agents, school/community-specific autonomy, demonstrated administrative leadership, higher-level support, dedicated champion(s) to engage school community, community support, quality and use of evidence, and professional development) and four contextual conditions (time, funding and project support, readiness and understanding, and prior community connectivity) were necessary, but made suggestions to modify two conditions (youth led and learning opportunities) to better reflect their experiences implementing IYMP. In addition, a new core condition, rooted in relationship, emerged as necessary for implementation. CONCLUSIONS: This research adds to the literature by identifying and describing what is needed in practice to implement a communal, relationship-based afterschool healthy living program. The essential conditions may support other researchers and communities interested in implementing and rippling similar programs.

Maternal body mass index, offspring body mass index, and blood pressure at 18 years: a causal mediation analysis.

OBJECTIVE: Understanding the natural history of hypertension is key to identifying prevention strategies. Previous work suggests that in utero exposures and offspring anthropometrics may play a role. This study examined the relationship between maternal pre-pregnancy body mass index (BMI) and the mediating role of childhood and adolescent BMI on offspring blood pressure at 18 years. METHODS: We performed multivariable regression and causal mediation analyses within 3217 mother - offspring pairs from the Avon Longitudinal Study of Parents and Children prospective birth cohort. The main exposure was maternal pre-pregnancy BMI, and the outcome was offspring blood pressure at 18 years of age categorized as normal or elevated. Latent trajectory analysis was used to quantify the mediator, offspring BMI trajectories, derived from multiple measurements throughout childhood and adolescence. Mediation analyses were repeated using current offspring BMI at 18 years as a continuous variable. RESULTS: Multivariable logistic regression revealed that for every 1 unit increase in maternal BMI, the risk of elevated blood pressure at 18 years of age increased by 5% (aOR: 1.05, 95% CI: 1.03-1.07; p < 0.001). The strength of this association was reduced after adjusting for offspring BMI trajectory (aOR: 1.03, 95% CI: 1.00-1.05; p = 0.017) and eliminated after adjusting for offspring BMI at 18 years (aOR: 1.00; 95% CI: 0.98-1.03; p = 0.70). Causal mediation analysis confirmed offspring BMI at 18 years as a mediator, where BMI trajectory accounted for 46% of the total effect of maternal BMI on elevated offspring blood pressure and current BMI account for nearly the entire effect. CONCLUSIONS: Maternal pre-pregnancy BMI is associated with an increased risk of elevated blood pressure in offspring at 18 years of age although it appears to be entirely mediated by offspring BMI.

Low risks for spiritual highs: Risk-taking behaviours and the protective benefits of spiritual health among Saskatchewan adolescents.

Objectives: Adolescent risk-taking behaviours, such as substance use and early sexual activity, can adversely impact physical health and psychosocial development. A connection to spiritual health may buffer against the negative health impacts of several risk-taking behaviours. The aim of this study was to determine if higher spiritual health was associated with lower risk-taking behaviours among school-attending adolescents in Saskatchewan, Canada. Methods: A representative sample of 4,751 adolescents in the Canadian province of Saskatchewan completed the Health Behaviour of School-aged Children (HBSC) questionnaire during the 2014 to 2015 school year. The main risk-taking behavioural outcomes were self-reported: smoking; alcohol; and cannabis use; as well as sexual intercourse. The main exposures related to spiritual health included four factors: connectedness to (1) one's self; (2) others; (3) nature; and (4) notions of the transcendent. Multivariable logistic regression analyses were used to test for associations between exposures and outcome measures. Results: The sample was balanced across gender, primarily Caucasian (71%), and primarily ages 11 to 15 years (48%). Adolescents indicated a high prevalence of spiritual health. Across all adjusted models, the results demonstrated that adolescents who value the various components of spiritual health showed a decreased likelihood of engaging in cigarette smoking, alcohol and marijuana use, and sexual intercourse. Conclusion: The findings indicate the potential for spiritual health to be considered as the basis for public- and community-health interventions, pending further evidence from experimental studies.

Intrauterine exposure to diabetes and risk of cardiovascular disease in adolescence and early adulthood: a population-based birth cohort study.

BACKGROUND: It is unclear whether intrauterine exposure to maternal diabetes is associated with risk factors for cardiovascular disease and related end points in adulthood. We examined this potential association in a population-based birth cohort followed up to age 35 years. METHODS: We performed a cohort study of offspring born between 1979 and 2005 (n = 293 546) and followed until March 2015 in Manitoba, Canada, using registry-based administrative data. The primary exposures were intrauterine exposure to gestational diabetes and type 2 diabetes mellitus. The primary outcome was a composite measure of incident cardiovascular disease events, and the secondary outcome was a composite of risk factors for cardiovascular disease in offspring followed up to age 35 years. RESULTS: The cohort provided 3 628 576 person-years of data (mean age at latest follow-up 20.5 [standard deviation 6.4] years, 49.3% female); 2765 (0.9%) of the offspring experienced a cardiovascular disease end point, and 12 673 (4.3%) experienced a cardiovascular disease risk factor. After propensity score matching, the hazard for cardiovascular disease end points was elevated in offspring exposed to gestational diabetes (adjusted hazard ratio [HR] 1.42, 95% confidence interval [CI] 1.12-1.79) but not type 2 diabetes (adjusted HR 1.40, 95% CI 0.98-2.01). A similar association was observed for cardiovascular disease risk factors (gestational diabetes: adjusted HR 1.92, 95% CI 1.75-2.11; type 2 diabetes: adjusted HR 3.40, 95% CI 3.00-3.85). INTERPRETATION: Intrauterine exposure to maternal diabetes was associated with higher morbidity and risk related to cardiovascular disease among offspring up to 35 years of age.

Cardiac structure and function in youth with type 2 diabetes in the iCARE cohort study: Cross-sectional associations with prenatal exposure to diabetes and metabolomic profiles.

OBJECTIVE: This study aimed to determine the degree of left ventricular (LV) dysfunction and its determinants in adolescents with type 2 diabetes (T2D). We hypothesized that adolescents with T2D would display impaired LV diastolic function and that these cardiovascular complications would be exacerbated in youth exposed to maternal diabetes in utero. METHODS: Left ventricular structure and function, carotid artery intima media thickness and strain, and serum metabolomic profiles were compared between adolescents with T2D (n = 121) and controls (n = 34). Sub-group analyses examined the role of exposure to maternal diabetes as a determinant of LV or carotid artery structure and function among adolescents with T2D. RESULTS: Adolescents with T2D were 15.1 ± 2.5 years old, (65% female, 99% Indigenous), had lived with diabetes for 2.7 ± 2.2 years, had suboptimal glycemic control (HbA1c = 9.4 ± 2.6%) and 58% (n = 69) were exposed to diabetes in utero. Compared to controls, adolescents with T2D displayed lower LV diastolic filling (early diastole/atrial filling rate ratio [E/A] = 1.9 ± 0.6 vs 2.2 ± 0.6, P = 0.012), lower LV relaxation and carotid strain (0.12 ± 0.05 vs 0.17 ± 0.05, P = .03) and elevated levels of leucine, isoleucine and valine. Among adolescents with T2D, exposure to diabetes in utero was not associated with differences in LV diastolic filling, LV relaxation, carotid strain or branched chain amino acids. CONCLUSIONS: Adolescents with T2D display LV diastolic dysfunction, carotid artery stiffness, and elevated levels of select branch chain amino acids; differences were not associated with exposure to maternal diabetes in utero.

Adverse childhood experiences are associated with an increased risk of obesity in early adolescence: a population-based prospective cohort study.

OBJECTIVE: To determine whether adverse childhood experiences were associated with weight gain and obesity risk in adolescence. METHODS: We analyzed data from 6942 adolescents followed between 9 and 13 years of age in the Growing Up in Ireland cohort study. The main exposures were 14 adverse childhood experiences, 4 of which were included in the Adverse Childhood Experience (ACE) study. The primary outcome was incident overweight and obesity at 13 years. Secondary outcomes included prevalent overweight/obesity and weight gain. RESULTS: More than 75% of the youth experienced an adverse experience and 17% experienced an ACE-specific experience before 9 years. At 13 years, 48% were female and 31.4% were overweight or obese. After adjusting for confounding, exposure to any adverse experience was associated with prevalent overweight/obesity (aOR: 1.56; 1.19-2.05) and incident overweight/obesity (adjusted IRR: 2.15; 95% CI: 1.37-3.39), while exposure to an ACE-specific exposure was associated weight gain (BMI Z score change = 0.202; 95% CI: 0.100-0.303). A significant interaction between income and adverse childhood experiences was observed for both incident overweight/obesity and weight gain (BMI Z change: -0.046; 95% CI: -0.092 to 0.000). CONCLUSIONS: Adverse childhood experiences and low income interact and independently predict obesity risk in early adolescence.

Scholarly training objectives and requirements for paediatric residents in Canada.

In the absence of national standards for scholarly requirements, paediatric resident training varies significantly across Canadian programs. This variability may contribute to significant differences in trainee experiences and productivity. A panel of coordinators of paediatric resident research programs from across Canada met in 2014, to share experiences and identify barriers to successful resident scholarly activity. A survey of all programs was completed in 2015. A scoping review and series of meetings led to the development of a proposed list of expectations, timelines for successful completion and consequences for not completing a scholarly project. We propose a harmonized list of scholarly competencies and activities for paediatric residents in Canada to accomplish before completing their training. We also propose that programs implement standardized timelines and consequences in the event that a resident does not meet their program's scholarly expectations.

Determinants of scholarly project completion in a paediatric resident program in Canada.

BACKGROUND: The primary aims of this study were to: 1) assess barriers and facilitators of completing scholarly projects from residents and faculty mentor perspectives, 2) determine the perceived value of new initiatives designed to support resident scholarly projects and 3) determine if these initiatives led to changes in resident publications. DESIGN AND METHODS: Between June and September 2014, we surveyed 18 paediatric residents and 41 faculty mentors regarding barriers to resident scholarly project completion and the value of new initiatives to support scholarly activity. We also tracked scientific publications by residents before and after implementation of these initiatives. RESULTS: The primary perceived barriers to research for residents and faculty were lack of protected time (64.3% versus 68.6%, respectively), lack of resident interest in scholarly activity (50.0% versus 60.0%, respectively) and lack of mentor motivation. Mentors and residents did not agree that lack of proper training in research (29% versus 54%, respectively) and faculty motivation (29% versus 17%, respectively) were barriers to completing a project. A dedicated research coordinator (71.4% versus 70.6%, respectively), a revised research curriculum (71.4% versus 41.2%, respectively) and works in progress sessions (50.0% versus 61.8%, respectively) were perceived as valuable initiatives to the program. These initiatives were not associated with changes in annual resident publication rates. CONCLUSIONS: Lack of time and competing clinical training are primary barriers to scholarly project completion for residents in addition to a lack of motivation on the part of faculty members. Improving program support was perceived as positive changes to address these barriers but did not increase resident publication rates. The information provided here could be used to tailor future resident research programs and highlight the value of gathering input from resident and faculty when designing initiatives to enhance resident research productivity.

Examining the impact of a province-wide physical education policy on secondary students' physical activity as a natural experiment.

BACKGROUND: The purpose of this paper is to examine the impact of a province-wide physical education (PE) policy on secondary school students' moderate to vigorous physical activity (MVPA). METHODS: Policy: In fall 2008, Manitoba expanded a policy requiring a PE credit for students in grades 11 and 12 for the first time in Canada. The PE curriculum requires grades 11 and 12 students to complete a minimum of 55 h (50% of course hours) of MVPA (e.g., ≥30 min/day of MVPA on ≥5 days a week) during a 5-month semester to achieve the course credit. STUDY DESIGNS: A natural experimental study was designed using two sub-studies: 1) quasi-experimental controlled pre-post analysis of self-reported MVPA data obtained from census data in intervention and comparison [Prince Edward Island (PEI)] provinces in 2008 (n = 33,619 in Manitoba and n = 2258 in PEI) and 2012 (n = 41,169 in Manitoba and n = 4942 in PEI); and, 2) annual objectively measured MVPA in cohorts of secondary students in intervention (n = 447) and comparison (Alberta; n = 224) provinces over 4 years (2008 to 2012). ANALYSIS: In Study 1, two logistic regressions were conducted to model the odds that students accumulated: i) ≥30 min/day of MVPA, and ii) met Canada's national recommendation of ≥60 min/day of MVPA, in Manitoba versus PEI after adjusting for grade, sex, and BMI. In Study 2, a mixed effects model was used to assess students' minutes of MVPA per day per semester in Manitoba and Alberta, adjusting for age, sex, BMI, school location and school SES. RESULTS: In Study 1, no significant differences were observed in students achieving ≥30 (OR:1.13, 95% CI:0.92, 1.39) or ≥60 min/day of MVPA (OR:0.92, 95% CI: 0.78, 1.07) from baseline to follow-up between Manitoba and PEI. In Study 2, no significant policy effect on students' MVPA trajectories from baseline to last follow-up were observed between Manitoba and Alberta overall (-1.52, 95% CI:-3.47, 0.42), or by covariates. CONCLUSIONS: The Manitoba policy mandating PE in grades 11 and 12 had no effect on student MVPA overall or by key student or school characteristics. However, the effect of the PE policy may be underestimated due to the use of a nonrandomized research design and lack of data assessing the extent of policy implementation across schools. Nevertheless, findings can provide evidence about policy features that may improve the PE policy in Manitoba and inform future PE policies in other jurisdictions.

Age and the risk of All-Terrain Vehicle-related injuries in children and adolescents: a cross sectional study.

BACKGROUND: The study was designed to determine if youth <16 years are at a greater risk of serious injuries related to all-terrain vehicle (ATV) use compared to older adolescents and adults. METHODS: We performed cross sectional study of children and adults presenting to pediatric and adult emergency departments between 1990 and 2009 in Canada. The primary exposure variable was age <16 years and the primary outcome measure was moderate to serious injury determined from physician report of type and severity of injury. RESULTS: Among 5005 individuals with complete data, 58% were <16 years and 35% were admitted to hospital. The odds of a moderate to serious injury versus minor injury among ATV users <16 years of age was not different compared with those ≥16 years of age (OR: 0.94; 95% CI: 0.84, 1.06). After adjusting for era, helmet use, sex and driver status, youth <16 years were more likely to present with a head injury (aOR: 1.45; 95% CI: 1.19-1.77) or fractures (aOR: 1.60; 95% CI: 1.43-1.81), compared with those ≥16 years. Male participants (aOR: 1.21; 95% CI: 1.06-1.38) and drivers (aOR: 1.30, 95% CI: 1.12-1.51) were more likely to experience moderate or serious injuries than females and passengers. Helmet use was associated with significant protection from head injuries (aOR: 0.59; 95% CI: 0.44-0.78). CONCLUSIONS: Youth under 16 years are at an increased risk of head injuries and fractures. For youth and adults presenting to emergency departments with an ATV-related injury, moderate to serious injuries associated with ATV use are more common among drivers and males. Helmet use protected against head injuries, suggesting minimum age limits for ATV use and helmet use are warranted.

Targeting skeletal muscle mitochondria to prevent type 2 diabetes in youth.

The prevalence of type 2 diabetes (T2D) has increased dramatically over the past two decades, not only among adults but also among adolescents. T2D is a systemic disorder affecting every organ system and is especially damaging to the cardiovascular system, predisposing individuals to severe cardiac and vascular complications. The precise mechanisms that cause T2D are an area of active research. Most current theories suggest that the process begins with peripheral insulin resistance that precedes failure of the pancreatic ß-cells to secrete sufficient insulin to maintain normoglycemia. A growing body of literature has highlighted multiple aspects of mitochondrial function, including oxidative phosphorylation, lipid homeostasis, and mitochondrial quality control in the regulation of peripheral insulin sensitivity. Whether the cellular mechanisms of insulin resistance in adults are comparable to that in adolescents remains unclear. This review will summarize both clinical and basic studies that shed light on how alterations in skeletal muscle mitochondrial function contribute to whole body insulin resistance and will discuss the evidence supporting high-intensity exercise training as a therapy to circumvent skeletal muscle mitochondrial dysfunction to restore insulin sensitivity in both adults and adolescents.

Lifestyle therapy for the treatment of youth with type 2 diabetes.

Type 2 diabetes (T2D) in youth is a relatively novel condition facing paediatric health care providers. Few experimental trials exist to guide clinical management in this population. Supporting and prescribing modifiable lifestyle behaviours is cornerstone in the management of T2D in adults. Clinical trials in obese adolescents suggest that intensive lifestyle interventions that include both dietary changes and increased physical activity elicit clinically meaningful reductions in weight and improve cardiovascular risk profiles. Observational studies in youth with T2D suggest that better diet quality and increased physical activity are associated with better metabolic control; however, the limited experimental data available does not support these observations. Trials evaluating lifestyle monotherapy for the treatment of hyperglycaemia in youth with T2D do not exist, and the only study evaluating combined lifestyle and pharmacologic therapy did not show additional benefit over pharmacologic treatment with metformin alone. Physiological and psychosocial differences between youth and adults with T2D likely contribute to the differences in the effectiveness of lifestyle therapy for improving glycaemic control. The current review describes these topics in detail and provides recommendations for paediatric health care providers for the promotion of lifestyle therapy for the management of hyperglycaemia and cardiovascular risk factors for youth with T2DM.

A clinically relevant method to screen for hepatic steatosis in overweight adolescents: a cross sectional study.

BACKGROUND: To develop a screening algorithm to detect hepatic steatosis in overweight and obese adolescents. METHODS: We performed a cross sectional study of 129 overweight adolescents 13-18 yrs. The primary outcome, hepatic steatosis was defined as an intracellular triglyceride content > 5.5 mg/g and quantified using (1)H-magenetic resonance spectroscopy. Primary predictor variables included, alanine and aspartate transaminases (ALT/AST) and features of the metabolic syndrome. RESULTS: Hepatic steatosis was present in 33% of overweight and obese adolescents. Adolescents with hepatic steatosis were more likely to be boys (adjusted OR: 4.8; 95% CI: 2.5-10.5), display a higher waist circumference (111 ± 12 vs 100 ± 13 cm, p < 0.001) and have metabolic syndrome (adjusted OR: 5.1; 95% CI: 1.6-16.4). Serum ALT predicted hepatic steatosis in boys (AUC: 0.82; 95% CI: 0.70-0.95; p < 0.001) but not girls (AUC = 0.63; 95% CI: 0.46-0.75, p = 0.16). An ALT >20 U/L, combined with the presence of metabolic syndrome, male gender and an elevated waist circumference provided the best model (AUC 0.85) with high sensitivity (72%) and specificity (82%) and positive and negative predictive values of 61% and 89% respectively. CONCLUSIONS: Serum transaminases provide modest predictive value for hepatic steatosis in youth. The ALT threshold for predicting hepatic steatosis is significantly lower than current clinical thresholds for predicting non-alcoholic fatty liver disease. The addition of ALT, presence of the metabolic syndrome and male gender significant improve the ability to predict hepatic steatosis.

The blood pressure response to exercise in youth with impaired glucose tolerance and type 2 diabetes.

Type 2 diabetes is associated with hypertension and an increased risk of cardiovascular disease. In adults, blood pressure (BP) responses to exercise are predictive of these complications. To determine if the hemodynamic response to exercise is exaggerated in youth with dysglycemia (DG) compared with normoglycemic overweight/ obese (OB) and healthy weight (HW) controls a cross-sectional comparison of BP and heart rate (HR) responses to graded exercise to exhaustion in participants was performed. DG and OB youth were matched for age, BMI z-score, height and sex. Systolic (SBP) and diastolic BP (DBP) were measured every 2 min, and HR was measured every 1 min. SBP was higher in OB and DG compared with HW youth at rest (p < .001). Despite working at lower relative workloads compared with HW, the BP response was elevated during exercise in OB and DG. For similar HR and oxygen consumption rates, BP responses to exercise were slightly higher in OB and DG compared with HW. OB and DG youth both display elevated resting and exercise BP relative to HW peers. Obesity may play a greater role than dysglycemia in the exaggerated BP response to exercise in youth.

Outdoor time is associated with physical activity, sedentary time, and cardiorespiratory fitness in youth.

OBJECTIVE: To determine whether time spent outdoors was associated with increased moderate-to-vigorous physical activity (MVPA) and related health benefits in youth. STUDY DESIGN: We performed a cross-sectional study of 306 youth aged 13.6 ± 1.4 years. The exposure of interest was self-reported time spent outdoors after school, stratified into three categories: none, some, and most/all of the time. The main outcome of interest was accelerometer-derived MVPA (Actical: 1500 to >6500 counts/min). Secondary outcomes included sedentary behavior, cardiorespiratory fitness, overweight status, and blood pressure. RESULTS: Among the 306 youth studied, those who reported spending most/all of their after-school time outdoors (n = 120) participated in more MVPA (61.0 ± 24.3 vs 39.9 ± 19.1 min/day; adjusted P < .001), were more likely to achieve the recommended minimum 60 min/day of MVPA (aOR 2.8; 95% CI, 1.3-6.4), spent less time in sedentary activities (539 ± 97 min/day vs 610 ± 146 min/day; adjusted P < .001), and had higher cardiorespiratory fitness (49 ± 5 vs 45 ± 6 mL/kg/min; adjusted P < .001) than youth who reported no time outdoors (n = 52). No differences in overweight/obesity or blood pressure were observed across the groups. CONCLUSIONS: Time spent outdoors is positively associated with MVPA and cardiorespiratory fitness in youth and negatively associated with sedentary behavior. Experimental trials are needed to determine whether strategies designed to increase time spent outdoors exert a positive influence on physical activity and fitness levels in youth.