David N. Collier

Sagittal and frontal plane joint mechanics throughout the stance phase of walking in adolescents who are obese.

The incidence of obesity has increased dramatically in children and adolescents, and with this comes health risks typically associated with adult obesity. Among those health consequences are musculoskeletal damage and pain. Previous studies have demonstrated inconsistent effects of increased body mass on movement patterns in adults and children who are obese. The purpose of this study was to investigate frontal and sagittal plane mechanics during walking in adolescents who were obese. Adolescents (12-17 years) who were obese were recruited from a weight management program, and healthy weight peers (matched for age, race and gender) were recruited from the community. Three-dimensional motion analysis of the lower extremities was performed during walking. Analysis of kinematic and kinetic data from 36 adolescents who were obese and healthy weight revealed significant differences in mechanics at all lower extremity joints in both sagittal and frontal planes. Subjects who were obese seemed to use movement strategies that minimized joint moments, especially at the hip and knee during walking. The lower extremity mechanics during walking in the subjects who were obese raise concerns about maintenance of structural integrity of the lower extremity joints over time, given the repeated high stresses across the joints even with walking. Neither the long term consequences of these atypical movement patterns, nor the ability to alter these patterns through therapeutic activities or weight loss has been investigated in adolescents who are obese.

Frontal plane lower extremity biomechanics during walking in boys who are overweight versus healthy weight.

Purpose: To compare frontal plane lower extremity biomechanics during walking in adolescent boys who were overweight (OW) versus healthy weight (HW). Methods: Fourteen boys (7 considered HW, body mass index for age <85th percentile; age 10.8 ± 0.7 years; 7 considered OW, body mass index for age >95th percentile; age 12.0 ± 0.7 years) participated. Three-dimensional kinematic data were collected during walking at self-selected speeds. Group means were compared using Students t tests (alpha = 0.05). Results: Significant differences were found in timing of rearfoot motions and moments, amplitude of knee motion peaks, timing of knee moment peaks, and timing and amplitudes of peak hip motion and moments. Conclusion: Boys who were OW collapsed into hip adduction and knee valgus during stance and attempted to compensate with rearfoot inversion. Observed differences in frontal plane kinematics during walking suggest that boys who are OW have increased risk of lower extremity musculoskeletal injuries and dysfunction.

Promising insights into the health related quality of life for children with severe obesity

BackgroundChildhood obesity is a growing health concern known to adversely affect quality of life in children and adolescents. The Patient Reported Outcomes Measurement Information System (PROMIS) pediatric measures were developed to capture child self-reports across a variety of health conditions experienced by children and adolescents. The purpose of this study is to begin the process of validation of the PROMIS pediatric measures in children and adolescents affected by obesity.MethodsThe pediatric PROMIS instruments were administered to 138 children and adolescents in a cross-sectional study of patient reported outcomes in children aged 8–17 years with age-adjusted body mass index (BMI) greater than the 85th percentile in a design to establish known-group validity. The children completed the depressive symptoms, anxiety, anger, peer relationships, pain interference, fatigue, upper extremity, and mobility PROMIS domains utilizing a computer interface. PROMIS domains and individual items were administered in random order and included a total of 95 items. Patient responses were compared between patients with BMI 85 to < 99th percentile versus ≥ 99th percentile.Results136 participants were recruited and had all necessary clinical data for analysis. Of the 136 participants, 5% ended the survey early resulting in missing domain scores at the end of survey administration. In multivariate analysis, patients with BMI ≥ 99th percentile had worse scores for depressive symptoms, anger, fatigue, and mobility (p < 0.05). Parent-reported exercise was associated with better scores for depressive symptoms, anxiety, and fatigue (p < 0.05).ConclusionsChildren and adolescents ranging from overweight to severely obese can complete multiple PROMIS pediatric measures using a computer interface in the outpatient setting. In the 5% with missing domain scores, the missing scores were consistently found in the domains administered last, suggesting the length of the assessment is important. The differences in domain scores found in this study are consistent with previous reports investigating the quality of life in children and adolescents with obesity. We show that the PROMIS instrument represents a feasible and potentially valuable instrument for the future study of the effect of pediatric obesity on quality of life.

Cutaneous infections from coastal and marine bacteria

The coastal and marine environments contain a variety of potentially pathogenic bacteria that can cause cutaneous infection. While some of these infections are relatively minor, some may be life threatening, especially in patients with certain risk factors. The most common and serious of these aquatic‐acquired infections are discussed, including 1) the marine vibrios, 2) Mycobacterium marinum, 3) erysipeloid and disseminated Erysipelothrix, and 4) Aeromonas hydrophila. Treatment of these is also discussed.

Impairments in site-specific AS160 phosphorylation and effects of exercise training

The purpose of this study was to determine if site-specific phosphorylation at the level of Akt substrate of 160 kDa (AS160) is altered in skeletal muscle from sedentary humans across a wide range of the adult life span (18–84 years of age) and if endurance- and/or strength-oriented exercise training could rescue decrements in insulin action and skeletal muscle AS160 phosphorylation. A euglycemic-hyperinsulinemic clamp and skeletal muscle biopsies were performed in 73 individuals encompassing a wide age range (18–84 years of age), and insulin-stimulated AS160 phosphorylation was determined. Decrements in whole-body insulin action were associated with impairments in insulin-induced phosphorylation of skeletal muscle AS160 on sites Ser-588, Thr-642, Ser-666, and phospho-Akt substrate, but not Ser-318 or Ser-751. Twelve weeks of endurance- or strength-oriented exercise training increased whole-body insulin action and reversed impairments in AS160 phosphorylation evident in insulin-resistant aged individuals. These findings suggest that a dampening of insulin-induced phosphorylation of AS160 on specific sites in skeletal muscle contributes to the insulin resistance evident in a sedentary aging population and that exercise training is an effective intervention for treating these impairments.

Camp-Based Immersion Treatment for Obese, Low Socioeconomic Status, Multi-Ethnic Adolescents

BACKGROUND Immersion treatment (IT) provided in a camp setting has been shown to promote short-term improvements in weight and health status in obese adolescents. However, evidence of ITs long-term efficacy and efficacy for multi-ethnic and lower socioeconomic status (SES) adolescents is limited. METHODS This was a cohort study with a pre/post design and longitudinal follow-up. The intervention was a 19-day camp-based IT program comprising (1) a nutrition curriculum and ad-lib access to a nutritious diet, (2) several hours of physical activity daily, (3) group therapy, and (4) cognitive-behavioral therapy (CBT). This analysis included 52 low-SES adolescents that participated in 2009 and 2010. A subgroup of 33 campers and their families was offered follow-up monthly for 10 months. Primary outcome measures were change in weight-related parameters immediately postcamp and after 10 months of follow-up. RESULTS Campers had significant short-term improvements in mean waist circumference (mean [M], 2.6; standard deviation [SD], 3.2 cm), weight (M, 2.6; SD, 1.9 kg), BMI (M, 1.1; SD, 0.9 kg/m2), BMI z-score (M, 0.06; SD, 0.07), and percent overweight (M, 6.1; SD, 4.7). Campers offered follow-up had a modest increase in mean percent overweight (M, 2.0; SD, 8.4) during 10 months of follow-up. However, 33% experienced continuing decline in percent overweight during follow-up, and long-term follow-up was associated with significant overall (precamp vs. end of follow-up) improvements in percent overweight (M, 4.9; SD, 7.2). CONCLUSIONS Camp-based IT with CBT is a promising intervention for improving short- and long-term weight status of low-SES adolescents. Additional research is needed to increase long-term efficacy.

Quality of life and BMI changes in youth participating in an integrated pediatric obesity treatment program

BackgroundChanges in Quality of Life (QOL) measures over time with treatment of obesity have not previously been described for youth. We describe the changes from baseline through two follow up visits in youth QOL (assessed by the Pediatric Quality Life Inventory, PedsQL4.0), teen depression (assessed by the Patient Health Questionnaire, PHQ9A), Body Mass Index (BMI) and BMI z-score. We also report caregiver proxy ratings of youth QOL.MethodsA sample of 267 pairs of youth and caregiver participants were recruited at their first visit to an outpatient weight-treatment clinic that provides care integrated between a physician, dietician, and mental health provider; of the 267, 113 attended a visit two (V2) follow-up appointment, and 48 attended visit three (V3). We investigated multiple factors longitudinally experienced by youth who are overweight and their caregivers across up to three different integrated care visits. We determined relationships at baseline in QOL, PHQ9A, and BMI z-score, as well as changes in variables over time using linear mixed models with time as a covariate.ResultsOverall across three visits the results indicate that youth had slight declines in relative BMI, significant increases in their QOL and improvements in depression.ConclusionsWe encourage clinicians and researchers to track youth longitudinally throughout treatment to investigate not only youth’s BMI changes, but also psychosocial changes including QOL.

Fitness versus Fatness and Insulin Resistance in U.S. Adolescents

Background. The present study examined the relationship between insulin resistance and both waist circumference and cardiorespiratory fitness in U.S. adolescents. Methods. NHANES assessed a nationally representative sample of U.S. adolescents (12–18 yrs) between 1999–2002. Abdominal adiposity was estimated by waist circumference, overall adiposity by BMI, and cardiorespiratory fitness (maximal oxygen uptake (VO2max) from a treadmill exercise test). Insulin resistance was estimated from fasting insulin and glucose using the homeostatic model assessment method (i.e., HOMA) and was log-transformed. Results. 1078 adolescents were included in the study. Positive correlations existed between lnHOMA and waist circumference (r = 0.59; r = 0.54) for boys and girls, respectively. lnHOMA and VO2max were inversely related in boys (r = −0.29) but not girls (r = −0.06). Gender-specific analyses by BMI category showed that the significant inverse relationship in lnHOMA and VO2max was primarily present in obese boys. Conclusion. Among adolescents, important gender and BMI differences exist in the relationship between insulin resistance and fitness. While waist circumference and BMI are important predictors in all children, fitness appears especially important in obese boys. These findings may have important implications for gender-specific interventions to prevent adult obesity and diabetes mellitus.

Insulin Resistance Status: Predicting Weight Response in Overweight Children

OBJECTIVE To assess the relationship between insulin resistance and body mass index (BMI) z score associated with dietary modification that focuses on limiting sweetened beverage consumption in overweight children. DESIGN A retrospective cohort study conducted between July 1, 2004, and April 28, 2006. SETTING Community-based primary care practices treating children. PATIENTS Forty-five children (aged < or =18 years) at or above the 95th percentile of BMI for age and sex. Intervention Children and parents were instructed by a dietitian regarding caloric reduction and modification of sweetened beverage intake. MAIN OUTCOME MEASURES Insulin resistance at baseline was calculated from fasting insulin and glucose levels (ie, homeostatic model assessment [HOMA]) and change in BMI z score from baseline to 12-week follow-up. RESULTS Change in BMI z score in response to a decrease in sweetened beverages correlated (Pearson product moment correlation coefficient = 0.42; P < .01) with baseline insulin resistance. Those with a decrease in or an unchanged BMI z score had significantly greater insulin resistance than those whose BMI z score increased (mean [SD] HOMA, 6.2 [4.2] vs 2.6 [2.0], P < .01). Linear regression confirmed that HOMA was a significant predictor of change in BMI z score when controlling for age, race, and sex. CONCLUSIONS Among overweight children in primary care practices, a significant relationship was found between insulin resistance and the change in BMI z score associated with a dietitian-mediated intervention that includes a focus on decreasing sweetened beverage consumption. Estimating insulin resistance may inform dietary recommendations for overweight children.

Comparison of predictive equations and measured resting energy expenditure among obese youth attending a pediatric healthy weight clinic: one size does not fit all.

BACKGROUND The Academy of Nutrition and Dietetics recommends the use of indirect calorimetry for calculating caloric targets for weight loss in obese youth. Practitioners typically use predictive equations since indirect calorimetry is often not available. The objective of this study was to compare measured resting energy expenditure (MREE) with that estimated using published predictive equations in obese pediatric patients. MATERIAL AND METHODS Youth aged 7 to 18 years (n = 80) who were referred to a university-based healthy weight clinic and who were greater than the 95th percentile BMI for age and gender participated. MREE was measured via a portable indirect calorimeter. Predicted energy expenditure (pEE) was estimated using published equations including those commonly used in children. pEE was compared to the MREE for each subject. Absolute mean difference between MREE and pEE, mean percentage accuracy, and mean error were determined. RESULTS Mean percentage accuracy of pEE compared with MREE varied widely, with the Harris-Benedict, Lazzer, and Molnar equations providing the greatest accuracy (65%, 61%, and 60%, respectively). Mean differences between MREE and equation-estimated caloric targets varied from 197.9 kcal/day to 307.7 kcal/day. CONCLUSIONS The potential to either overestimate or underestimate calorie needs in the clinical setting is significant when comparing EE derived from predictive equations with that measured using portable indirect calorimetry. While our findings suggest that the Harris-Benedict equation has improved accuracy relative to other equations in severely obese youth, the potential for error remains sufficiently great to suggest that indirect calorimetry is preferred.