A Youth Compendium of Physical Activities: Activity Codes and Metabolic Intensities.

Purpose: A Youth Compendium of Physical Activities (Youth Compendium) was developed to estimate the energy costs of physical activities using data on youth only.

Methods: On the basis of a literature search and pooled data of energy expenditure measurements in youth, the energy costs of 196 activities were compiled in 16 activity categories to form a Youth Compendium of Physical Activities. To estimate the intensity of each activity, measured oxygen consumption (V˙O2) was divided by basal metabolic rate (Schofield age-, sex-, and mass-specific equations) to produce a youth MET (METy).

Functional data analysis of sleeping energy expenditure.

Adequate sleep is crucial during childhood for metabolic health, and physical and cognitive development. Inadequate sleep can disrupt metabolic homeostasis and alter sleeping energy expenditure (SEE). Functional data analysis methods were applied to SEE data to elucidate the population structure of SEE and to discriminate SEE between obese and non-obese children.

Energy Cost of Activities in Preschool-Aged Children.

Background: The absolute energy cost of activities in children increase with age due to greater muscle mass and physical capability associated with growth and developmental maturation; however, there is a paucity of data in preschool-aged children. Study aims were 1) to describe absolute and relative energy cost of common activities of preschool-aged children in terms of VO2, energy expenditure (kilocalories per minute) and child-specific metabolic equivalents (METs) measured by room calorimetry for use in the Youth Compendium of Physical Activity, and 2) to predict METs from age, sex and heart rate (HR).

Methods: Energy expenditure (EE), oxygen consumption (VO2), HR, and child-METs of 13 structured activities were measured by room respiration calorimetry in 119 healthy children, ages 3 to 5 years.

Role of physical activity and sleep duration in growth and body composition of preschool-aged children.

Objective: The impact of physical activity patterns and sleep duration on growth and body composition of preschool-aged children remains unresolved. Aims were (1) to delineate cross-sectional associations among physical activity components, sleep, total energy expenditure (TEE), and body size and composition; and (2) to determine whether physical activity components, sleep, and TEE predict 1-year changes in body size and composition in healthy preschool-aged children.

Methods: Anthropometry, body composition, accelerometry, and TEE by doubly labeled water were measured at baseline; anthropometry and body composition were repeated 1 year later (n = 111).

Global metabolomic profiling targeting childhood obesity in the Hispanic population.

Background: Metabolomics may unravel important biological pathways involved in the pathophysiology of childhood obesity.

Objectives: We aimed to 1) identify metabolites that differ significantly between nonobese and obese Hispanic children; 2) collapse metabolites into principal components (PCs) associated with obesity and metabolic risk, specifically hyperinsulinemia, hypertriglyceridemia, hyperleptinemia, and hyperuricemia; and 3) identify metabolites associated with energy expenditure and fat oxidation.

Design: This trial was a cross-sectional observational study of metabolomics by using gas chromatography-mass spectrometry and ultrahigh-performance liquid chromatography-tandem mass spectrometry analyses performed on fasting plasma samples from 353 nonobese and 450 obese Hispanic children.

Energetic adaptations persist after bariatric surgery in severely obese adolescents.

Objective: Energetic adaptations induced by bariatric surgery have not been studied in adolescents or for extended periods postsurgery. Energetic, metabolic, and neuroendocrine responses to Roux-en-Y gastric bypass (RYGB) surgery were investigated in extremely obese adolescents.

Methods: At baseline and at 1.

Individual differences in susceptibility to large portion sizes among obese and normal-weight children.

Objective: Determine the association of children's susceptibility to large food portion sizes with appetite regulation and obesity.

Methods: Normal-weight and obese non-Hispanic black children (n = 100) aged 5-6 years were observed in four dinner conditions of varying portion size; portions of all foods (except milk) offered were: 100% (677 kcal), 150% (1015 kcal), 200% (1353 kcal), or 250% (1691 kcal) of those in the reference condition (100%). Condition order was randomly assigned to 2-4 children who ate together at each meal.

Revision of Dietary Reference Intakes for energy in preschool-age children.

Background: Dietary Reference Intakes (DRI) for energy aim to balance energy expenditure at a level of physical activity consistent with health and support adequate growth in children. DRIs were derived from total energy expenditure (TEE) measured by using the doubly labeled water (DLW) method; however, the database was limited in the 3-5-y-old range.

Objective: We reexamined the DRI for energy for preschool-age children.

Support vector machines classifiers of physical activities in preschoolers.

The goal of this study is to develop, test, and compare multinomial logistic regression (MLR) and support vector machines (SVM) in classifying preschool-aged children physical activity data acquired from an accelerometer. In this study, 69 children aged 3-5 years old were asked to participate in a supervised protocol of physical activities while wearing a triaxial accelerometer. Accelerometer counts, steps, and position were obtained from the device.

Prediction of energy expenditure and physical activity in preschoolers.

Purpose: Accurate, nonintrusive, and feasible methods are needed to predict energy expenditure (EE) and physical activity (PA) levels in preschoolers. Herein, we validated cross-sectional time series (CSTS) and multivariate adaptive regression splines (MARS) models based on accelerometry and heart rate (HR) for the prediction of EE using room calorimetry and doubly labeled water (DLW) and established accelerometry cut points for PA levels.

Methods: Fifty preschoolers, mean ± SD age of 4.

Multivariate path analysis of serum 25-hydroxyvitamin D concentration, inflammation, and risk of type 2 diabetes mellitus.

Background And Aims: Despite growing interest in the protective role that vitamin D may have in health outcomes, little research has examined the mechanisms underlying this role. This study aimed to test two hypotheses: (1) serum 25-hydroxyvitamin D [25(OH)D] is inversely associated with type 2 diabetes mellitus (T2DM) and elevated hemoglobin A1c; (2) these associations are mediated by serum C-reactive protein (CRP).

Methods: Participants aged 20 and older in 2001-2006 National Health and Nutrition Examination Surveys (n = 8,655) with measures of serum 25(OH)D, CRP, hemoglobin A1c, and other important covariates were included in the present study.

Modeling energy expenditure in children and adolescents using quantile regression.

Advanced mathematical models have the potential to capture the complex metabolic and physiological processes that result in energy expenditure (EE). Study objective is to apply quantile regression (QR) to predict EE and determine quantile-dependent variation in covariate effects in nonobese and obese children. First, QR models will be developed to predict minute-by-minute awake EE at different quantile levels based on heart rate (HR) and physical activity (PA) accelerometry counts, and child characteristics of age, sex, weight, and height.

Cross-sectional time series and multivariate adaptive regression splines models using accelerometry and heart rate predict energy expenditure of preschoolers.

Prediction equations of energy expenditure (EE) using accelerometers and miniaturized heart rate (HR) monitors have been developed in older children and adults but not in preschool-aged children. Because the relationships between accelerometer counts (ACs), HR, and EE are confounded by growth and maturation, age-specific EE prediction equations are required. We used advanced technology (fast-response room calorimetry, Actiheart and Actigraph accelerometers, and miniaturized HR monitors) and sophisticated mathematical modeling [cross-sectional time series (CSTS) and multivariate adaptive regression splines (MARS)] to develop models for the prediction of minute-by-minute EE in 69 preschool-aged children.

Validation of uniaxial and triaxial accelerometers for the assessment of physical activity in preschool children.

Purpose: Given the unique physical activity (PA) patterns of preschoolers, wearable electronic devices for quantitative assessment of physical activity require validation in this population. Study objective was to validate uniaxial and triaxial accelerometers in preschoolers.

Methods: Room calorimetry was performed over 3 hours in 64 preschoolers, wearing Actical, Actiheart, and RT3 accelerometers during play, slow, moderate, and fast translocation.

Validation of cross-sectional time series and multivariate adaptive regression splines models for the prediction of energy expenditure in children and adolescents using doubly labeled water.

Accurate, nonintrusive, and inexpensive techniques are needed to measure energy expenditure (EE) in free-living populations. Our primary aim in this study was to validate cross-sectional time series (CSTS) and multivariate adaptive regression splines (MARS) models based on observable participant characteristics, heart rate (HR), and accelerometer counts (AC) for prediction of minute-by-minute EE, and hence 24-h total EE (TEE), against a 7-d doubly labeled water (DLW) method in children and adolescents. Our secondary aim was to demonstrate the utility of CSTS and MARS to predict awake EE, sleep EE, and activity EE (AEE) from 7-d HR and AC records, because these shorter periods are not verifiable by DLW, which provides an estimate of the individual's mean TEE over a 7-d interval.

Multivariate adaptive regression splines models for the prediction of energy expenditure in children and adolescents.

Advanced mathematical models have the potential to capture the complex metabolic and physiological processes that result in heat production or energy expenditure (EE). Multivariate adaptive regression splines (MARS) is a nonparametric method that estimates complex nonlinear relationships by a series of spline functions of the independent predictors. The specific aim of this study is to construct MARS models based on heart rate (HR) and accelerometer counts (AC) to accurately predict EE, and hence 24-h total EE (TEE), in children and adolescents.

Are energy dense diets also nutrient dense?

Objective: Some beverages are nutrient dense, but they are often excluded from nutrient density calculations. The purpose of this study was to assess whether the energy-nutrient association changed when beverages were included in these calculations.

Design: Applying a cross-sectional design, a 24-hour dietary recall was collected on each participant.

Metabolic and behavioral predictors of weight gain in Hispanic children: the Viva la Familia Study.

Background: Despite the high prevalence of overweight among Hispanic children in the United States, definitive predictors of weight gain have not been identified in this population.

Objective: The study objective was to test sociodemographic, metabolic, and behavioral predictors of 1-y weight gains in a large cohort of Hispanic children studied longitudinally.

Design: Subjects (n = 879) were siblings from 319 Hispanic families enrolled in the Viva la Familia Study.

Food-purchasing patterns for home: a grocery store-intercept survey.

Objectives: To identify the most common frequency of food-purchasing patterns and relate this pattern to characteristics of individuals and families.

Design: A customer-intercept survey was conducted in the greater Houston area, Texas, USA, in 2002. The frequency of food shopping at supermarkets, convenience stores and restaurants to buy food for eating at home was assessed.

Relationships between maternal and child cardiovascular risk factors: ethnic differences and lack of influence of physical activity.

Objectives: To obtain information about the relationship between cardiovascular and diabetic risk factors of mothers and their children and to determine whether these relationships differ by physical activity or ethnicity.

Design: Prospective study.

Setting: The Texas site of the Studies of Child Activity and Nutrition Program.

Comparison of dietary intakes associated with metabolic syndrome risk factors in young adults: the Bogalusa Heart Study.

Background: Previous studies suggested that dietary intakes affect individual risk factors associated with metabolic syndrome.

Objective: The objective of this study was to examine dietary intakes in 1181 young adults aged 19-38 y (38.1% men; 25% African Americans and 75% whites) in relation to metabolic syndrome risk factors in the Bogalusa Heart Study.