Energy Expenditure of Common Sedentary Activities in Youth.

BACKGROUND: Standardized measures of energy expenditure (EE) for sedentary activities in youth are needed. The goal was to determine EE of common contemporary and computer-related sedentary activities in youth. METHODS: We measured EE for sedentary tasks in 10- to 17-year-old youths (n = 24) during ~24 hours in a whole-room indirect calorimeter. Directly monitored tasks were performed for ~10-min. EE was calculated from oxygen consumed and carbon dioxide produced, converted to metabolic equivalents (MET) by normalization to an individual's measured resting EE, and compared with the Compendium of Energy Expenditures for Youth. RESULTS: Compared with the youth compendium, measured METs were lower for internet surfing (1.3), computer keyboard typing (1.3), and sorting beads/crafts (1.5) (all P < .002), and similar for handwriting (1.4), playing cards (1.6), video-gaming (1.6), and telephoning (1.5). CONCLUSIONS: Current youth compendium MET estimates should be used with caution when predicting EE of common contemporary and computer-related sedentary activities in youth.

Comparative assessment of change in fat mass using dual X-ray absorptiometry and air-displacement plethysmography.

OBJECTIVE: To compare the accuracy of body composition measurements to small, defined changes in fat mass between dual X-ray absorptiometry (DXA) and air-displacement plethysmography (ADP). METHODS: Fifty-six healthy adults, 29 women and 27 men (age, 38 ± 12.4 years; BMI, 27.6 ± 5.8 kg/m2) were included in the study. Exclusion criteria were pregnancy, indwelling metal hardware or pacemakers, or weight exceeding DXA table limit (>350 lbs). All individual testing was completed within a 2-hour period. Fat packets were prepared using lard wrapped in plastic and applied exogenously in defined locations. Each participant completed body composition measurements with ADP and DXA (both testing modalities completed with and without 1 kg of exogenously applied fat mass). RESULTS: Both DXA and ADP were highly accurate in detecting an overall increase in body mass associated with exogenously applied 1kg of fat mass (0.99 kg vs. 0.97 kg, respectively). DXA more accurately detected exogenous fat increase as fat mass compared to ADP (0.93 kg; 90% CI for the mean of the difference: 0.83 to 1.03 kg vs. 0.45 kg; 90% CI: 0.19 to 0.71 kg, respectively). The accuracy of body mass detection was similar for males and females (0.97 vs. 1.02 for DXA and 0.92 vs. 1.02 for ADP, respectively), though accuracy in detecting added mass as fat was less accurate in males than females (0.84 vs. 1.00 for DXA and 0.39 vs. 0.51 for ADP, respectively). DISCUSSION: Both DXA and ADP are accurate in detecting an overall increase in body mass associated with exogenously applied 1kg of fat mass. However, DXA is more accurate than ADP in correctly identifying the increase in body mass as fat mass, as opposed to fat free mass.

Effect of BMI on prediction of accelerometry-based energy expenditure in youth.

PURPOSE: The objective of this study is to determine the effect of body mass index (BMI) on level of agreement between six previously established prediction equations for three commonly used accelerometers to predict summary measures of energy expenditure (EE) in youth. METHODS: One hundred and thirty-one youth between the ages of 10-17 yr and BMI from 15 to 44 kg·m were outfitted with hip-worn ActiGraph GT1M (Pensacola, FL), Actical (MiniMiter/Respironics, Bend, OR), and RT3 (StayHealthy, Monrovia, CA) accelerometers and spent approximately 24 h in a whole-room indirect calorimeter while performing structured and self-selected activities. Five commonly used regression and one propriety equations for each device were used to predict the minute-to-minute EE (normalized to METs), daily physical activity level (PAL), and time spent in sedentary, light, moderate, and vigorous physical activity intensity categories. The calculated values were compared with criterion measurements obtained from the room calorimeter. RESULTS: All predictive equations, except RT3, significantly over- or underpredicted daily PAL (P < 0.001), with large discrepancies observed in the estimate of sedentary and light activity. Discrepancies between actual and estimated PAL ranged from 0.05 to 0.68. In addition, BMI represented a modifier for two ActiGraph predictive equations (AG1 and AG2), affecting the accuracy of physical activity-related EE predictions. CONCLUSION: ActiGraph (AG3) and the RT3 closely predicted overall PAL (within 4.2% and 6.8%, respectively) as a group. When adjusting for age, sex, and ethnicity, Actical (AC1 and AC2) and ActiGraph (AG3) were not influenced by BMI. However, a gap between some hip-worn accelerometer predictive and regression equations was demonstrated compared with both criterion measurement and each other, which poses a potential difficulty for interstudy (e.g., different accelerometers) and intrastudy (e.g., BMI and adiposity) comparisons.

Nutrition education for pediatric gastroenterology, hepatology, and nutrition fellows: survey of NASPGHAN fellowship training programs.

OBJECTIVES: The aim of the study was to assess the methodology and content of nutrition education during gastroenterology fellowship training and the variability among the different programs. METHODS: A survey questionnaire was completed by 43 fellowship training directors of 62 active programs affiliated to the North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition, including sites in the United States, Canada, and Mexico. The data were examined for patterns in teaching methodology and coverage of specific nutrition topics based on level 1 training in nutrition, which is the minimum requirement according to the published North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition fellowship training guidelines. RESULTS: The majority of the teaching was conducted by MD-degree faculty (61%), and most of the education was provided through clinical care experiences. Only 31% of the level 1 nutrition topics were consistently covered by >80% of programs, and coverage did not correlate with the size of the programs. Competency in nutrition training was primarily assessed through questions to individuals or groups of fellows (77% and 65%, respectively). Program directors cited a lack of faculty interested in nutrition and a high workload as common obstacles for teaching. CONCLUSIONS: The methodology of nutrition education during gastroenterology fellowship training is, for the most part, unstructured and inconsistent among the different programs. The minimum level 1 requirements are not consistently covered. The development of core curriculums and learning modules may be beneficial in improving nutrition education.

Pediatric patients with dyspepsia have chronic symptoms, anxiety, and lower quality of life as adolescents and adults.

BACKGROUND & AIMS: Little is known about long-term health outcomes of children with dyspeptic symptoms. We studied the natural history of pediatric patients with dyspeptic symptoms, with and without histologic reflux, compared with healthy controls. METHODS: We performed a prospective study of consecutive new patients, ages 8-16 years, who underwent evaluation for dyspepsia, including upper endoscopy. Patients were assigned to groups with histologic evidence of reflux esophagitis (n = 50), or normal histology results (n = 53). Healthy children were followed up as controls (n = 143). Patients and controls were evaluated 5-15 years later. They provided self-reports on severity of dyspeptic symptoms, use of acid suppression, quality of life, anxiety, and depression. RESULTS: When the study began, the groups with histologic evidence of esophagitis and normal histologies did not differ in severity of dyspeptic symptoms, functional disability, or depression. After a mean 7.6-year follow-up period, each group had significantly lower quality-of-life scores and more severe dyspeptic symptoms and functional disability than controls, but did not differ significantly from each other; both groups were significantly more likely than controls to meet criteria for an anxiety disorder. At time of follow-up evaluation, use of acid-suppression medication was significantly greater in the group with histologic evidence for esophagitis, compared with patients who had normal histology findings when the study began. CONCLUSIONS: Among pediatric patients with dyspepsia evaluated by endoscopy and biopsy, those with histologic evidence for esophagitis or normal histology findings are at increased risk for chronic dyspeptic symptoms, anxiety disorder, and reduced quality of life in adolescence and young adulthood.

Distributed lag and spline modeling for predicting energy expenditure from accelerometry in youth.

Movement sensing using accelerometers is commonly used for the measurement of physical activity (PA) and estimating energy expenditure (EE) under free-living conditions. The major limitation of this approach is lack of accuracy and precision in estimating EE, especially in low-intensity activities. Thus the objective of this study was to investigate benefits of a distributed lag spline (DLS) modeling approach for the prediction of total daily EE (TEE) and EE in sedentary (1.0-1.5 metabolic equivalents; MET), light (1.5-3.0 MET), and moderate/vigorous (> or = 3.0 MET) intensity activities in 10- to 17-year-old youth (n = 76). We also explored feasibility of the DLS modeling approach to predict physical activity EE (PAEE) and METs. Movement was measured by Actigraph accelerometers placed on the hip, wrist, and ankle. With whole-room indirect calorimeter as the reference standard, prediction models (Hip, Wrist, Ankle, Hip+Wrist, Hip+Wrist+Ankle) for TEE, PAEE, and MET were developed and validated using the fivefold cross-validation method. The TEE predictions by these DLS models were not significantly different from the room calorimeter measurements (all P > 0.05). The Hip+Wrist+Ankle predicted TEE better than other models and reduced prediction errors in moderate/vigorous PA for TEE, MET, and PAEE (all P < 0.001). The Hip+Wrist reduced prediction errors for the PAEE and MET at sedentary PA (P = 0.020 and 0.021) compared with the Hip. Models that included Wrist correctly classified time spent at light PA better than other models. The means and standard deviations of the prediction errors for the Hip+Wrist+Ankle and Hip were 0.4 +/- 144.0 and 1.5 +/- 164.7 kcal for the TEE, 0.0 +/- 84.2 and 1.3 +/- 104.7 kcal for the PAEE, and -1.1 +/- 97.6 and -0.1 +/- 108.6 MET min for the MET models. We conclude that the DLS approach for accelerometer data improves detailed EE prediction in youth.

Predicting energy expenditure of physical activity using hip- and wrist-worn accelerometers.

To investigate the association between physical activity and health, we need accurate and detailed free-living physical activity measurements. The determination of energy expenditure of activity (EEACT) may also be useful in the treatment and maintenance of nutritional diseases such as diabetes mellitus. Minute-to-minute energy expenditure during a 24-h period was measured in 60 sedentary normal female volunteers (35.4 +/- 9.0 years, body mass index 30.0 +/- 5.9 kg/m2), using a state-of-the-art whole-room indirect calorimeter. The activities ranged from sedentary deskwork to walking and stepping at different intensities. Body movements were simultaneously measured using a hip-worn triaxial accelerometer (Tritrac-R3D, Hemokentics, Inc., Madison, Wisconsin) and a wrist-worn uniaxial accelerometer (ActiWatch AW64, MiniMitter Co., Sunriver, Oregon) on the dominant arm. Movement data from the accelerometers were used to develop nonlinear prediction models (separately and combined) to estimate EEACT and compared for accuracy. In a subgroup (n=12), a second 24-h study period was repeated for cross-validation of the combined model. The combined model, using Tritrac-R3D and ActiWatch, accurately estimated total EEACT (97.7 +/- 3.2% of the measured values, p=0.781), as compared with using ActiWatch (86.0 +/- 4.7%, p<0.001) or Tritrac-R3D (90.0 +/- 4.6%, p<0.001) alone. This model was also accurate for all intensity categories during various physical activities. The subgroup cross-validation also showed accurate and reproducible predictions by the combination model. In this study, we demonstrated that movement measured using accelerometers at the hip and wrist could be used to accurately predict EEACT of various types and intensity of activities. This concept can be extended to develop valid models for the accurate measurement of free-living energy metabolism in clinical populations.