Ambient air pollutants are associated with morning serum cortisol in overweight and obese Latino youth in Los Angeles.

BACKGROUND: Hypothalamic-pituitary-adrenal (HPA)-axis dysfunction has been associated with a variety of mental health and cardio-metabolic disorders. While causal models of HPA-axis dysregulation have been largely focused on either pre-existing health conditions or psychosocial stress factors, recent evidence suggests a possible role for central nervous system activation via air pollutants, such as nitrogen dioxide (NO2), ozone (O3) and particulate matter (PM). Therefore, in an observational study of Latino youth, we investigated if monthly ambient NO2, O3, and PM with aerodynamic diameter ≤ 2.5 (PM2.5) exposure were associated with morning serum cortisol levels. METHODS: In this cross-sectional study, morning serum cortisol level was assessed after a supervised overnight fast in 203 overweight and obese Latino children and adolescents (female/male: 88/115; mean age: 11.1 ± 1.7 years; pre-pubertal/pubertal/post-pubertal: 85/101/17; BMI z-score: 2.1 ± 0.4). Cumulative concentrations of NO2, O3 and PM2.5 were spatially interpolated at the residential addresses based on measurements from community monitors up to 12 months prior to testing. Single and multi-pollutant linear effects models were used to test the cumulative monthly lag effects of NO2, O3, and PM2.5 on morning serum cortisol levels after adjusting for age, sex, seasonality, social position, pubertal status, and body fat percent by DEXA. RESULTS: Single and multi-pollutant models showed that higher O3 exposure (derived from maximum 8-h exposure windows) in the prior 1-7 months was associated with higher serum morning cortisol (p < 0.05) and longer term PM2.5 exposure (4-10 months) was associated with lower serum morning cortisol levels (p < 0.05). Stratification by pubertal status showed associations in pre-pubertal children compared to pubertal and post-pubertal children. Single, but not multi-pollutant, models showed that higher NO2 over the 4-10 month exposure period associated with lower morning serum cortisol (p < 0.05). CONCLUSIONS: Chronic ambient NO2, O3 and PM2.5 differentially associate with HPA-axis dysfunction, a mechanism that may serve as an explanatory pathway in the relationship between ambient air pollution and metabolic health of youth living in polluted urban environments. Further research that uncovers how ambient air pollutants may differentially contribute to HPA-axis dysfunction are warranted.

Effects of consuming sugars and alternative sweeteners during pregnancy on maternal and child health: evidence for a secondhand sugar effect.

Consumption of sugar and alternative low- or no-energy sweeteners has increased in recent decades. However, it is still uncertain how consumption of sugar and alternative sweeteners during pregnancy affects pregnancy outcomes and long-term offspring health. This review aims to collate the available evidence surrounding the consequences of sugar and alternative sweetener consumption during pregnancy, a so-called secondhand sugar effect. We found evidence that sugar consumption during pregnancy may contribute to increased gestational weight gain and the development of pregnancy complications, including gestational diabetes, preeclampsia and preterm birth. Further, we found a growing body of the animal and human evidence that maternal sugar intake during pregnancy may impact neonatal and childhood metabolism, taste perception and obesity risk. Emerging evidence also suggests that both maternal and paternal preconception sugar intakes are linked to offspring metabolic outcomes, perhaps via epigenetic alterations to the germline. While there have been fewer studies of the impacts of alternative sweetener consumption before and during pregnancy, there is some evidence to suggest effects on infant outcomes including preterm birth risk, increased infant body composition and offspring preference for sweet foods, although mechanisms are unclear. We conclude that preconception and gestational sugar and alternative sweetener consumption may negatively impact pregnancy outcomes and offspring health and that there is a need for further observational, mechanistic and intervention research in this area.

Consumption of artificial sweetened beverages associated with adiposity and increasing HbA1c in Hispanic youth.

Research examining the impact of artificial sweetened beverages (ASBs) on obesity and metabolic diseases in adolescents is limited. The overall goal is to examine the longitudinal effects of ASBs on changes in adiposity and metabolic parameters in Hispanic adolescents. Longitudinal cohort with 98 Hispanics (12-18 years) who were overweight or had obesity with the following data at baseline and 1-year later: anthropometrics, diet (24-h recalls), body composition (DXA), glucose and insulin dynamics (oral glucose tolerance and frequently sampled intravenous glucose tolerance test) and fasting lipids. Repeated measures analyses of covariance assessed changes over time between control (no ASBs at either visit), ASB initiators (no ASBs at baseline/ASBs at 1-year) and chronic ASB consumers (ASBs at both visits). ASB initiators (n = 14) and chronic ASB consumers (n = 9) compared to control (n = 75) had higher total body fat at baseline and 1-year (P = 0.05 for group effect). Chronic ASB consumers had a 6% increase in haemoglobin A1c, 34% increase in energy intake (kcal d-1 ) and 39% increase in carbohydrate intake (g d-1 ) over time, while control and ASB initiators maintained (P < 0.05 for group-by-time interactions). These results do not support promoting ASBs as a strategy for adiposity loss or to improve metabolic health.

Pathways and mechanisms linking dietary components to cardiometabolic disease: thinking beyond calories.

Calories from any food have the potential to increase risk for obesity and cardiometabolic disease because all calories can directly contribute to positive energy balance and fat gain. However, various dietary components or patterns may promote obesity and cardiometabolic disease by additional mechanisms that are not mediated solely by caloric content. Researchers explored this topic at the 2017 CrossFit Foundation Academic Conference 'Diet and Cardiometabolic Health - Beyond Calories', and this paper summarizes the presentations and follow-up discussions. Regarding the health effects of dietary fat, sugar and non-nutritive sweeteners, it is concluded that food-specific saturated fatty acids and sugar-sweetened beverages promote cardiometabolic diseases by mechanisms that are additional to their contribution of calories to positive energy balance and that aspartame does not promote weight gain. The challenges involved in conducting and interpreting clinical nutritional research, which preclude more extensive conclusions, are detailed. Emerging research is presented exploring the possibility that responses to certain dietary components/patterns are influenced by the metabolic status, developmental period or genotype of the individual; by the responsiveness of brain regions associated with reward to food cues; or by the microbiome. More research regarding these potential 'beyond calories' mechanisms may lead to new strategies for attenuating the obesity crisis.

Probiotic supplementation increases obesity with no detectable effects on liver fat or gut microbiota in obese Hispanic adolescents: a 16-week, randomized, placebo-controlled trial.

BACKGROUND: Numerous studies have shown that there are links between obesity, liver fat and the gut microbiome. However, there are mixed results on whether probiotics could impact the gut microbiome and/or help to decrease liver fat and obesity outcomes. OBJECTIVE: This study aimed to determine whether a probiotic supplement (VSL#3® ) intervention altered gut microbiota and/or gut hormones associated with appetite regulation. The secondary aim of this study was to determine whether VSL#3® altered body composition and liver fat and fibrosis. METHODS: We conducted a double-blind, randomized placebo-controlled trial in 19 obese Latino adolescents. The intervention consisted of three packets per day of VSL#3® or a matched placebo for 16 weeks. Pre-intervention and post-intervention measures included gut microbial abundance, gut appetite regulating hormones, anthropometrics, body composition, liver fat and liver fibrosis. We conducted linear models to determine whether there were any significant differences in the changes in these outcomes following VSL#3® intervention. RESULTS: Compared with placebo, adolescents that received VSL#3 had significant increases in total adiposity (%) (+1.7 ± 0.6 vs. -1.3 ± 0.5, p < 0.01) and trunk adiposity (%) (+3.3 ± 0.8 vs. -1.8 ± 0.8, p < 0.01) with no significant effects on liver fat/fibrosis, insulin/glucose, gut microbial abundances or gut hormones. CONCLUSION: VSL#3 supplementation may lead to increased adiposity in obese Latino adolescents with no significant detectable changes in gut microbiota, gut appetite-regulating hormones, liver fat and fibrosis and dietary intake. However, it is important to note that recruitment efforts were terminated early and the sample size fell short of what was planned for this trial.

Simplified and age-appropriate recommendations for added sugars in children.

Excess sugar intake increases risk for obesity and related comorbidities among children. The World Health Organization (WHO), American Heart Association (AHA) and the 2015 USDA dietary recommendations have proposed guidelines for added sugar intake to reduce risk for disease. WHO and USDA recommendations are presented as a percentage of daily calories from added sugar. This approach is not easily understood or translated to children, where energy needs increase with age. The AHA recommendation is based on a fixed value of 25 g of added sugar for all children 2-19 years of age. This approach does not take into account the different levels of intake across this wide age range. Due to these limitations, we adapted current recommendations for added sugars based on daily energy needs of children 2-19 years. We used those values to derive simple regression equations to predict grams or teaspoons of added sugars per day based on age that would be equivalent to 10% of daily energy needs. This proposed approach aligns with the changing nutritional needs of children and adolescents during growth.

Effects of air pollution exposure on glucose metabolism in Los Angeles minority children.

OBJECTIVES: Growing evidence indicates that ambient (AAP: NO2 , PM2.5 and O3 ) and traffic-related air pollutants (TRAP) contribute to metabolic disease risk in adults; however, few studies have examined these relationships in children. METHODS: Metabolic profiling was performed in 429 overweight and obese African-American and Latino youth living in urban Los Angeles, California. This cross-sectional study estimated individual residential air pollution exposure and used linear regression to examine relationships between air pollution and metabolic outcomes. RESULTS: AAP and TRAP exposure were associated with adverse effects on glucose metabolism independent of body fat percent. PM2.5 was associated with 25.0% higher fasting insulin (p < 0.001), 8.3% lower insulin sensitivity (p < 0.001), 14.7% higher acute insulin response to glucose (p = 0.001) and 1.7% higher fasting glucose (p < 0.001). Similar associations were observed for increased NO2 exposure. TRAP from non-freeway roads was associated with 12.1% higher insulin (p < 0.001), 6.9% lower insulin sensitivity (p = 0.02), 10.8% higher acute insulin response to glucose (p = 0.003) and 0.7% higher fasting glucose (p = 0.047). CONCLUSIONS: Elevated air pollution exposure was associated with a metabolic profile that is characteristic of increased risk for type 2 diabetes. These results indicate that increased prior year exposure to air pollution may adversely affect type 2 diabetes-related pathophysiology in overweight and obese minority children.

Home visitation programs: an untapped opportunity for the delivery of early childhood obesity prevention.

BACKGROUND: Extant obesity efforts have had limited impact among low-income underserved children, in part because of limitations inherent to existing programs: (i) short duration and low intensity; (ii) late timing of implementation, when children are already overweight or obese; (iii) intervention delivery limiting their accessibility and sustainability; and (iv) failure to address barriers such as a lack of culturally competent services, poverty and housing instability, which interfere with healthy lifestyle changes. OBJECTIVE: This concept paper proposes an innovative model of obesity prevention implemented in infancy and sustained throughout early childhood to address the limitations of current obesity prevention efforts. Specifically, we propose to integrate sustained, weekly, in-home obesity prevention as part of the services already delivered by ongoing Home Visitation Programs, which currently do not target obesity prevention. CONCLUSION: The home visiting structure represents an ideal model for impactful obesity prevention as home visitation programs: (i) already provide comprehensive services to diverse low-income infants and families who are most at risk for obesity and poor health because of socio-economic and structural conditions; (ii) services are initiated in infancy and sustained throughout critical developmental periods for the formation of healthy/unhealthy behaviors; and (iii) have been in place for more than 40 years, with a widespread presence across the United States and nationwide, which is critical for the scalability and sustainability of obesity prevention.

Saturation of subcutaneous adipose tissue expansion and accumulation of ectopic fat associated with metabolic dysfunction during late and post-pubertal growth.

BACKGROUND/OBJECTIVE: Puberty is a period defined by large changes in adipose tissue accumulation and distribution; however, longitudinal patterns of ectopic fat development have not been shown. We have previously shown significant declines in beta-cell function (BCF) across puberty and hypothesize that accumulation of ectopic fat deposition, particularly hepatic fat, will predict this fall. SUBJECT/METHODS: We conducted a longitudinal study and examined 2-year change in abdominal fat distribution and type 2 diabetes risk markers in 76 Hispanic children and young adults (16.1±0.5 years, 66% obese, 52% male, 51% post-pubertal). Subcutaneous abdominal adipose tissue (SAAT), visceral adipose tissue (VAT), hepatic fat fraction (HFF) and pancreatic fat fraction (PFF) were measured by 3-Tesla magnetic resonance imaging, and markers of type 2 diabetes risk were collected at fasting and during an oral glucose tolerance test (OGTT). RESULTS: Baseline pubertal status significantly moderated the 2-year change in ectopic fat deposition, such that VAT, HFF and PFF increased in individuals during late and post-pubertal growth, whereas children earlier in their pubertal development decreased ectopic accumulation and had less VAT accumulation (VAT: pTanner*time=0.044, 0.31±0.08 l vs 0.03±0.10 l; HFF: pTanner*time=0.007, 1.34±0.87% vs -2.61±1.11%; PFF: pTanner*time<0.001, 1.61±0.39% vs -0.96±0.50%). Independent of pubertal status, the 2-year increase in HFF and VAT significantly associated with a decline in BCF (ß=-1.04, P=0.038; ß=-1.81, P=0.020) and metabolic function, while accumulation of SAAT significantly associated with BCF (ß=1.36, P=0.012) and metabolic improvement. HFF accumulation was the only depot to significantly predict clinical markers of type 2 diabetes risk, fasting glucose and HbA1c, and circulating free fatty acid levels (ß=1.00, P=0.034; ß=1.00, P=0.015; ß=01.01, P=0.024). CONCLUSIONS: The accumulation of SAAT defends against type 2 diabetes risk and potentially ectopic fat accumulation. Intra-abdominal VAT and HFF accumulation both associate with metabolic decline and BCF, while HFF predicts an even greater number of metabolic risk features.

Dietary fibre linked to decreased inflammation in overweight minority youth.

OBJECTIVE: The objective of this study was to examine the relationship between diet and inflammation, and adiposity in minority youth. DESIGN AND METHODS: The study was designed as a cross-sectional analysis of 142 overweight (≥85th body mass index percentile) Hispanic and African-American adolescents (14-18 years) with the following measures: anthropometrics, adiposity via magnetic resonance imaging, dietary intake via 24-h dietary recalls, and inflammation markers from fasting blood draws utilizing a multiplex panel. Partial correlations were estimated and analysis of covariance (ancova) models fit to examine the relationship among dietary variables, inflammation markers and adiposity measures with the following a priori covariates: Tanner stage, ethnicity, sex, total energy intake, total body fat and total lean mass. RESULTS: Inference based on ancova models showed that the highest tertile of fibre intake (mean intake of 21.3 ± 6.1 g d(-1) ) vs. the lowest tertile of fibre intake (mean intake of 7.4 ± 1.8 g d(-1) ) was associated with 36% lower plasminogen activator inhibitor-1 (P = 0.02) and 43% lower resistin (P = 0.02), independent of covariates. Similar results were seen for insoluble fibre. No other dietary variables included in this study were associated with inflammation markers. CONCLUSIONS: These results suggest that increases in dietary fibre could play an important role in lowering inflammation and therefore metabolic disease risk in high-risk minority youth.

Forefronts in portion size. An overview and synthesis of a roundtable discussion.

Establishing eating habits in early life that include appropriate portion sizes of foods which are nutrient dense and low in energy density is considered important in the prevention of obesity in children. This special supplement presents the proceedings of a symposium focusing on advances in scientific understanding of the development of healthy food portion sizes in children and their families. Recent basic research highlights individual differences in children's responsiveness to portion size as well as potential mechanisms of portion size effects. Quantitative approaches highlight the influence of maternal serving in determining intake, while qualitative approaches seek to elaborate caregiver decisions around child portion sizes at meals and snacks. Family-based environmental interventions for child weight control involving food portion size are outlined. An overview of the overarching issues and roundtable discussion on the forefronts of portion size research are presented as well as policy considerations to promote healthy portion control.

Insulin sensitivity and brain reward activation in overweight Hispanic girls: a pilot study.

BACKGROUND: Insulin resistance is a link between obesity and the associated disease risk. In addition to its role as an energy regulatory signal to the hypothalamus, insulin also modulates food reward. OBJECTIVE: To examine the relationship of insulin sensitivity (SI) and fasting insulin with cerebral activation in response to food and non-food cues in children. METHODS: Twelve overweight Hispanic girls (age: 8-11) participated in two study visits, a frequently sampled intravenous glucose tolerance test and a functional neuroimaging session (GE HDxt 3.0Tesla) with visual stimulation tasks. Blocks of images (high calorie [HC], low calorie [LC] and non-food [NF]) were presented in randomized order. RESULTS: Comparing HC with NF, SI was inversely associated with activation in the anterior cingulate (r(2) = 0.65; P < 0.05), the insula (r(2) = 0.69; P < 0.05), the orbitofrontal cortex (r(2) = 0.74; P < 0.05), and the frontal and rolandic operculum (r(2) = 0.76; P < 0.001). Associations remained significant after adjustment for body mass index. Association of fasting insulin and cerebral activation disappeared after adjustment for waist circumference. CONCLUSION: In addition to weight loss, insulin sensitivity may pose an important target to regulate neural responses to food cues in the prevention of excessive weight gain.

Increased eating frequency linked to decreased obesity and improved metabolic outcomes.

BACKGROUND: We previously reported that more frequent eating in overweight minority youth was linked to lower visceral adiposity and circulating triglycerides. The aim of this study was to examine this issue in more detail by assessing the relationship between eating frequency and adiposity and metabolic disease risk in a cohort of exclusively overweight Hispanic youth. METHODS: This analysis included 191 overweight (⩾ 85th percentile body mass index (BMI)) Hispanic youth (8-18 years) with the following cross-sectional measures: height, weight, BMI, dietary intake via multiple 24 h recalls, body composition via dual-energy X-ray absorptiometry, lipids and insulin action (insulin sensitivity, acute insulin response (AIR) and disposition index, a measure of ß-cell function) via a frequently sampled intravenous glucose tolerance test. Each eating occasion (EO) was defined as ⩾ 50 calories and ⩾ 15 min from any prior EO. Infrequent eaters (IEs) were classified as any subject who ate <3 EOs on any dietary recall (n = 32), whereas frequent eaters (FEs) always consumed ⩾ 3 EOs (n = 159). RESULTS: Using analyses of covariance, FEs compared with IEs consumed 23% more calories per day (P ⩽ 0.01), ate 40% more often and consumed 19% less calories per EO (P ⩽ 0.01). FEs also exhibited 9% lower BMI Z-scores (P ⩽ 0.01), 9% lower waist circumferences (P ⩽ 0.01), 29% lower fasting insulin (P = 0.02), 31% lower HOMA-IR (Homeostatic Model Assessment: Insulin Resistance) values (P = 0.02) and 19% lower triglycerides (P ⩽ 0.01), as well as an 11% higher AIR (P = 0.02) and 31% higher disposition index (P=0.01). The following a priori covariates were included: Tanner, sex, body fat and reported energy intake. CONCLUSION: These findings suggest that increased eating frequency is related to decreased obesity and metabolic disease risk in overweight Hispanic youth, despite increases in energy intake.

A novel biopsy method to increase yield of subcutaneous abdominal adipose tissue.

Collection of abdominal subcutaneous adipose tissue (SAT) for research testing is traditionally performed using punch biopsy or needle aspiration techniques, yielding small amounts of very superficial SAT (100-500 mg). Although liposuction techniques can be used to obtain large amounts of SAT, these approaches can compromise the integrity of the adipose tissue. Therefore, we investigated a novel method using a 6-mm Bergström side-cutting biopsy needle to acquire suitable amounts of intact abdominal SAT for multiple complex studies such as flow cytometry, RNA extraction, ex vivo expression of molecular and post-translational protein mediators, and histology. Fifty biopsies were obtained from 29 participants using a Bergström biopsy needle, applying transient manual suction and shearing large pieces of fat within the inner-cutting trochar. Eighteen of the biopsies were performed under ultrasound guidance, whereby we successfully sampled deep SAT (dSAT) from below Scarpa's fascia. The average weight of SAT sampled was 1.5 ± 0.4 g. There was no clinically important bleeding or ecchymosis on the abdominal wall and no infection occurred with this procedure. The 6-mm Bergström biopsy needle yielded substantially more SAT than what has been obtained from superficial procedures and, for the first time, allowed sampling of dSAT by a percutaneous approach.

Relationship between artificially sweetened and sugar-sweetened cola beverage consumption during pregnancy and preterm delivery in a multi-ethnic cohort: analysis of the Born in Bradford cohort study.

The aim of this study was to investigate the relationship between the intake of sugar-sweetened (SS) and artificially sweetened (AS) cola beverages during pregnancy and the risk of preterm delivery (PTD). At baseline (2007-2010), 8914 pregnant women were recruited to the Born in Bradford birth cohort study at 24-28 weeks of pregnancy. Women completed a questionnaire describing their health and lifestyle behaviours, including their consumption of AS and SS cola beverages reported as cups per day, which were then linked to maternity records. The relationship between SS and AS cola beverage consumption was examined using logistic regression analyses. No relationship was observed between daily AS cola beverage consumption and PTD. Women who drank four cups per day of SS cola beverages had higher odds of a PTD when compared with women who did not consume these beverages daily. We conclude that high daily consumption of SS cola beverages during pregnancy is associated with increases in the rate of PTD.

Compensatory responses to insulin resistance in obese African-American and Latina girls.

PURPOSE: Insulin responses to oral and intravenous glucose markedly differ by ethnicity. This study examined whether ethnic differences in pancreatic insulin secretion, hepatic insulin extraction and clearance explain these disparate findings in 35 obese African-American and 41 Latina girls (Tanner Stages: IV-V; ages: 14-18; body mass index percentile: 85.9-99.8%). METHODS: Pancreatic insulin secretion, hepatic insulin extraction and clearance were estimated by C-peptide and insulin modeling during an oral glucose tolerance test. Insulin sensitivity (SI), acute insulin response to glucose (AIRG ) and disposition index were derived from a frequently sampled intravenous glucose tolerance test. RESULTS: Compared to Latinas, obese African-American adolescents had lower pancreatic insulin secretion (21.3%; P < 0.01), glucose incremental area under the curve (IAUC) (41.7%, P = 0.02), C-peptide IAUC (25.1%, P < 0.01) and SI (33.7%; P < 0.01). There were no ethnic differences in hepatic insulin extraction and clearance (P's > 0.05). CONCLUSIONS: Compensatory mechanisms to insulin resistance do not appear to explain the ethnic differences in insulin responses to oral and intravenous glucose in obese African-American and Latina girls.

The association between community-level economic hardship and childhood obesity prevalence in Los Angeles.

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT: Neighbourhood social, economic and environmental factors are associated with childhood obesity. Childhood obesity disproportionately impacts those living in low-income neighbourhoods. WHAT THIS STUDY ADDS: Childhood obesity prevalence is strongly associated with community-level social and economic conditions as measured using a composite Economic Hardship Index. Childhood obesity prevalence among communities in the highest hardship quartile was more than double the prevalence among communities in the lowest hardship quartile (26.9 vs. 12.5%). The relationship between economic hardship and obesity differs by race/ethnicity. OBJECTIVE: The association between community-level economic hardship and childhood obesity prevalence was examined in Los Angeles County, one of the largest and most racially and ethnically diverse regions in the United States. METHODS: Data from the 2008-2009 California Department of Education's Physical Fitness Testing Program were analyzed to assess obesity prevalence among 5th, 7th and 9th grade students attending public schools (n = 298,485). Community-level socioeconomic conditions were compared using a census-tract-based Economic Hardship (EH) index. Mixed-effects modelling was used to examine the association between obesity prevalence and gender, grade, race/ethnicity and EH. RESULTS: Higher community-level EH was associated with higher childhood obesity prevalence (P < 0.001). The obesity prevalence among communities in the highest EH quartile (26.9%) was more than double the obesity prevalence among communities in the lowest EH quartile (12.5%). The slope of the association between EH and childhood obesity differed by racial/ethnic group. The slope was higher for non-Hispanic White students, Hispanics, and non-Hispanic Asians, and lower for non-Hispanic Black students. Racial/ethnic disparities were observed across the socioeconomic spectrum. CONCLUSIONS: Findings suggest that efforts to improve community socioeconomic conditions could reduce childhood obesity prevalence. Prevention efforts should target communities with high economic hardship and also focus on providing culturally relevant interventions that address disparities in obesity prevalence across communities.

Adiposity in children and adolescents: correlates and clinical consequences of fat stored in specific body depots.

The 2011 Pennington Biomedical Research Center's Scientific Symposium focused on adiposity in children and adolescents. The symposium was attended by 15 speakers and other invited experts. The specific objectives of the symposium were to (i) integrate the latest published and unpublished findings on the laboratory and clinical assessment of depot-specific adiposity in children and adolescents, (ii) understand the variation in depot-specific adiposity and related health outcomes associated with age, sex, maturation, ethnicity and other factors and (iii) identify opportunities for incorporating new markers of abdominal obesity into clinical practice guidelines for obesity in children and adolescents. This symposium provided an overview of important new advances in the field and identified directions for future research. The long-term goal of the symposium is to aid in the early identification of children and adolescents who are at increased health risk because of obesity and obesity-related conditions.

Use of MRI and CT for fat imaging in children and youth: what have we learned about obesity, fat distribution and metabolic disease risk?

Childhood obesity is a matter of great concern for public health. Efforts have been made to understand its impact on health through advanced imaging techniques. An increasing number of studies focus on fat distribution and its associations with metabolic risk, in interaction with genetics, environment and ethnicity, in children. The present review is a qualitative synthesis of the existing literature on visceral and subcutaneous abdominal, intrahepatic and intramuscular fat. Our search revealed 80 original articles. Abdominal as well as ectopic fat depots are prevalent already in childhood and contribute to abnormal metabolic parameters, starting early in life. Visceral, hepatic and intramuscular fat seem to be interrelated but their patterns as well as their independent contribution on metabolic risk are not clear. Some ethnic-specific characteristics are also prevalent. These results encourage further research in childhood obesity by using imaging techniques such as magnetic resonance imaging and computed tomography. These imaging methods can provide a better understanding of fat distribution and its relationships with metabolic risk, compared to less detailed fat and obesity assessment. However, studies on bigger samples and with a prospective character are warranted.

Effects of a randomized maintenance intervention on adiposity and metabolic risk factors in overweight minority adolescents.

OBJECTIVE: The objective of this study was to assess the effects of a maintenance programme (monthly newsletters vs. monthly group classes and telephone behavioural sessions) on obesity and metabolic disease risk at 1 year in overweight minority adolescents. METHODS: After a 4-month nutrition and strength training intervention, 53 overweight Latino and African-American adolescents (15.4 ± 1.1 years) were randomized into one of two maintenance groups for 8 months: monthly newsletters (n = 23) or group classes (n = 30; monthly classes + individualized behavioural telephone sessions). The following outcomes were measured at months 4 (immediately following the intense intervention) and 12: height, weight, blood pressure, body composition via BodPod™ (Life Measurement Instruments, Concord, CA, USA), lipids and glucose/insulin indices via frequently sampled intravenous glucose tolerance test. RESULTS: There were no significant group by time interactions for any of the health outcomes. There were significant time effects in several outcomes for both groups from months 4 to 12: bench press and leg press decreased by 5% and 14%, respectively (P = 0.004 & P = 0.01), fasting insulin and acute insulin response decreased by 26% and 16%, respectively (P < 0.001 & P = 0.046); while high-density lipoprotein cholesterol and insulin sensitivity improved by 5% and 14% (P = 0.042 & P = 0.039). CONCLUSIONS: Newsletters as opposed to group classes may suffice as follow-up maintenance programmes to decrease type 2 diabetes and cardiovascular risk in overweight minority adolescents.