Publications by authors named "Catherine L Davis"

47 Publications

Exercise and Academic Performance Among Children With Attention-Deficit Hyperactivity Disorder and Disruptive Behavior Disorders: A Randomized Controlled Trial.

Pediatr Exerc Sci 2020 05 25;32(3):140-149. Epub 2020 May 25.

University of Illinois at Chicago.

Purpose: To examine effects of a 10-week after-school physical activity (PA) program on academic performance of 6- to 12-year-old African American children with behavior problems.

Methods: Participants were randomized to PA (n = 19) or sedentary attention control (n = 16) programs. Academic records, curriculum-based measures, and classroom observations were obtained at baseline, postintervention, and/or follow-up. Mixed models tested group × time interactions on academic records and curriculum-based measures. One-way analysis of variance or Kruskal-Wallis tested for differences in postintervention classroom observations.

Results: Intent-to-treat analyses demonstrated a moderate effect within groups from baseline to postintervention on disciplinary referrals (PA: d = -0.47; attention control: d = -0.36) and a null moderate effect on academic assessments (PA: d = 0.11 to 0.36; attention control: d = 0.05 to 0.40). No significant group × time interactions emerged on direct academic assessments (all Ps ≥ .05, d = -0.23 to 0.26) or academic records (all Ps ≥ .05, d = -0.28 to 0.16). Classroom observations revealed that intervention participants were off-task due to moving at twice the rate of comparative classmates (F = 15.74, P < .001) and were off-task due to talking 33% more often (F = 1.39, P = .257).

Conclusion: Academic outcome improvements were small within and between groups and did not sustain at follow-up. Academic benefits of after-school PA programs for children with attention-deficit hyperactivity disorder and/or disruptive behavior disorders were smaller than neurobiological, behavioral, and cognitive outcomes as previously reported.
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http://dx.doi.org/10.1123/pes.2019-0224DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7686101PMC
May 2020

Placenta membranacea associated with a normal pregnancy and term vaginal delivery.

Pathology 2020 Feb 28;52(2):281-283. Epub 2019 Dec 28.

The University of Sydney Northern Clinical School, Clinical and Population Perinatal Health Research, St Leonards, NSW, Australia; Northern Sydney Local Health District, Kolling Institute, NSW, Australia.

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http://dx.doi.org/10.1016/j.pathol.2019.09.017DOI Listing
February 2020

Exercise effects on arterial stiffness and heart health in children with excess weight: The SMART RCT.

Int J Obes (Lond) 2020 05 21;44(5):1152-1163. Epub 2019 Nov 21.

Pediatrics, MCG, Augusta University, Augusta, GA, USA.

Introduction: Childhood obesity and inactivity are associated with cardiovascular risk. Evidence is limited for exercise effects on arterial health in children.

Methods: One hundred and seventy-five inactive children with overweight or obesity (8-11 years, ≥85th percentile BMI, 61% female, 87% Black, 73% with obesity) were randomized to an 8-month daily after-school aerobic exercise program (40 min/day, n = 90) or a sedentary control condition (n = 85). Carotid-femoral pulse wave velocity (PWV, primary outcome, arterial stiffness), fitness, adiposity, blood pressure (BP), glucose, insulin resistance, lipids, and C-reactive protein were measured at baseline and posttest (8 months). Adiposity, fitness, and BP were measured again at follow-up, 8-12 months later. Intent-to-treat analyses were conducted using mixed models.

Results: The study had 89% retention, with attendance of 59% in exercise and 64% in the control condition, and vigorous exercise participation (average heart rate 161 ± 7 beats/min). Compared with controls, the exercise group had twice the improvement in fitness (VȮ peak, 2.7 (95% CI 1.8, 3.6) vs. 1.3 (0.4, 2.3) mL/kg/min) and adiposity (-1.8 (-2.4, -1.1) vs. -0.8 (-1.5, -0.1)%), each p = 0.04, and a large improvement in HDL-cholesterol (0.13 (0.075, 0.186) vs. -0.028 (-0.083, 0.023) mmol/L, p < 0.0001). There was no group × time effect on other outcomes at 8 months, or on any outcomes at follow-up. The change in PWV at 8 months correlated with changes in insulin and insulin resistance (both r = 0.32), diastolic BP (r = 0.24), BMI (r = 0.22), and adiposity (r = 0.18).

Conclusions: Eight months of aerobic exercise training improved fitness, adiposity, and HDL-cholesterol levels, but did not reduce arterial stiffness in children with excess weight. PWV improved as a function of insulin resistance, BP, BMI, and adiposity. Weight loss may be required to improve arterial stiffness. Exercise benefits waned after discontinuing the program.
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http://dx.doi.org/10.1038/s41366-019-0482-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7192762PMC
May 2020

Exercise effects on quality of life, mood, and self-worth in overweight children: the SMART randomized controlled trial.

Transl Behav Med 2019 05;9(3):451-459

Department of Population Health Sciences, Georgia Prevention Institute, Medical College of Georgia, Augusta University, Augusta, GA, USA.

Overweight children are at risk for poor quality of life (QOL), depression, self-worth, and behavior problems. Exercise trials with children have shown improved mood and self-worth. Few studies utilized an attention control condition, QOL outcomes, or a follow-up evaluation after the intervention ends. The purpose is to test effects of an exercise program versus sedentary program on psychological factors in overweight children. One hundred seventy-five overweight children (87% black, 61% female, age 9.7 ± 0.9 years, 73% obese) were randomized to an 8 month aerobic exercise or sedentary after-school program. Depressive symptoms, anger expression, self-worth, and QOL were measured at baseline and post-test. Depressive symptoms and QOL were also measured at follow-up. Intent-to-treat mixed models evaluated intervention effects, including sex differences. At post-test, QOL, depression, and self-worth improved; no group by time or sex by group by time interaction was detected for QOL or self-worth. Boys' depressive symptoms improved more and anger control decreased in the sedentary intervention relative to the exercise intervention at post-test. At follow-up, depressive symptoms in boys in the sedentary group decreased more than other groups. Exercise provided benefits to QOL, depressive symptoms, and self-worth comparable to a sedentary program. Sedentary programs with games and artistic activities, interaction with adults and peers, and behavioral structure may be more beneficial to boys' mood than exercise. Some benefits of exercise in prior studies are probably attributable to program elements such as attention from adults. Trial Registration: Clinicaltrials.gov, NCT02227095.
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http://dx.doi.org/10.1093/tbm/ibz015DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6520810PMC
May 2019

The role of DNA methylation in the association between childhood adversity and cardiometabolic disease.

Int J Cardiol 2018 Mar 24;255:168-174. Epub 2017 Dec 24.

Department of Population Health Sciences, Medical College of Georgia, Augusta University, Augusta, GA, United States. Electronic address:

Growing evidence suggests that adverse environmental stimuli, especially during sensitive periods in early life, may lead to cardiometabolic disease in later life. However, the underlying biological mechanisms remain a mystery. Recent studies inferred that epigenetic modifications are likely involved. We review recent studies, primarily focused on the findings from human studies, to indicate the role of DNA methylation in the associations between childhood adversity and cardiometabolic disease in adulthood. In particular, we focused on DNA methylation modifications in genes regulating the hypothalamus-pituitary-adrenal axis as well as the immune system.
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http://dx.doi.org/10.1016/j.ijcard.2017.12.063DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5807118PMC
March 2018

Fitness, Sleep-Disordered Breathing, Symptoms of Depression, and Cognition in Inactive Overweight Children: Mediation Models.

Public Health Rep 2017 Nov/Dec;132(2_suppl):65S-73S

5 Georgia Prevention Institute, Augusta University, Augusta, GA, USA.

Objectives: We used mediation models to examine the mechanisms underlying the relationships among physical fitness, sleep-disordered breathing (SDB), symptoms of depression, and cognitive functioning.

Methods: We conducted a cross-sectional secondary analysis of the cohorts involved in the 2003-2006 project PLAY (a trial of the effects of aerobic exercise on health and cognition) and the 2008-2011 SMART study (a trial of the effects of exercise on cognition). A total of 397 inactive overweight children aged 7-11 received a fitness test, standardized cognitive test (Cognitive Assessment System, yielding Planning, Attention, Simultaneous, Successive, and Full Scale scores), and depression questionnaire. Parents completed a Pediatric Sleep Questionnaire. We used bootstrapped mediation analyses to test whether SDB mediated the relationship between fitness and depression and whether SDB and depression mediated the relationship between fitness and cognition.

Results: Fitness was negatively associated with depression ( B = -0.041; 95% CI, -0.06 to -0.02) and SDB ( B = -0.005; 95% CI, -0.01 to -0.001). SDB was positively associated with depression ( B = 0.99; 95% CI, 0.32 to 1.67) after controlling for fitness. The relationship between fitness and depression was mediated by SDB (indirect effect = -0.005; 95% CI, -0.01 to -0.0004). The relationship between fitness and the attention component of cognition was independently mediated by SDB (indirect effect = 0.058; 95% CI, 0.004 to 0.13) and depression (indirect effect = -0.071; 95% CI, -0.01 to -0.17).

Conclusions: SDB mediates the relationship between fitness and depression, and SDB and depression separately mediate the relationship between fitness and the attention component of cognition.
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http://dx.doi.org/10.1177/0033354917731308DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5692181PMC
December 2017

Prevention of diabetes in overweight/obese children through a family based intervention program including supervised exercise (PREDIKID project): study protocol for a randomized controlled trial.

Trials 2017 08 10;18(1):372. Epub 2017 Aug 10.

Department of Health Sciences, Public University of Navarra, Pamplona, Spain.

Background: The global pandemic of obesity has led to an increased risk for prediabetes and type-2 diabetes (T2D). The aims of the current project are: (1) to evaluate the effect of a 22-week family based intervention program, including supervised exercise, on insulin resistance syndrome (IRS) risk in children with a high risk of developing T2D and (2) to identify the profile of microRNA in circulating exosomes and in peripheral blood mononuclear cells in children with a high risk of developing T2D and its response to a multidisciplinary intervention program including exercise.

Methods: A total of 84 children, aged 8-12 years, with a high risk of T2D will be included and randomly assigned to control (N = 42) or intervention (N = 42) groups. The control group will receive a family based lifestyle education and psycho-educational program (2 days/month), while the intervention group will attend the same lifestyle education and psycho-educational program plus the exercise program (3 days/week, 90 min per session including warm-up, moderate to vigorous aerobic activities, and strength exercises). The following measurements will be evaluated at baseline prior to randomization and after the intervention: fasting insulin, glucose and hemoglobin A1c; body composition (dual-energy X-ray absorptiometry); ectopic fat (magnetic resonance imaging); microRNA expression in circulating exosomes and in peripheral blood mononuclear cells (MiSeq; Illumina); cardiorespiratory fitness (cardiopulmonary exercise testing); dietary habits and physical activity (accelerometry).

Discussion: Prevention and identification of children with a high risk of developing T2D could help to improve their cardiovascular health and to reduce the comorbidities associated with obesity.

Trial Registration: ClinicalTrials.gov, ID: NCT03027726 . Registered on 16 January 2017.
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http://dx.doi.org/10.1186/s13063-017-2117-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5551009PMC
August 2017

A whole brain volumetric approach in overweight/obese children: Examining the association with different physical fitness components and academic performance. The ActiveBrains project.

Neuroimage 2017 10 5;159:346-354. Epub 2017 Aug 5.

PROFITH "PROmoting FITness and Health Through Physical Activity" Research Group, Department of Physical Education and Sport, Faculty of Sport Sciences, University of Granada, Spain.

Obesity, as compared to normal weight, is associated with detectable structural differences in the brain. To the best of our knowledge, no previous study has examined the association of physical fitness with gray matter volume in overweight/obese children using whole brain analyses. Thus, the aim of this study was to examine the association between the key components of physical fitness (i.e. cardiorespiratory fitness, speed-agility and muscular fitness) and brain structural volume, and to assess whether fitness-related changes in brain volumes are related to academic performance in overweight/obese children. A total of 101 overweight/obese children aged 8-11 years were recruited from Granada, Spain. The physical fitness components were assessed following the ALPHA health-related fitness test battery. T1-weighted images were acquired with a 3.0 T S Magnetom Tim Trio system. Gray matter tissue was calculated using Diffeomorphic Anatomical Registration Through Exponentiated Lie algebra (DARTEL). Academic performance was assessed by the Batería III Woodcock-Muñoz Tests of Achievement. All analyses were controlled for sex, peak high velocity offset, parent education, body mass index and total brain volume. The statistical threshold was calculated with AlphaSim and further Hayasaka adjusted to account for the non-isotropic smoothness of structural images. The main results showed that higher cardiorespiratory fitness was related to greater gray matter volumes (P < 0.001, k = 64) in 7 clusters with β ranging from 0.493 to 0.575; specifically in frontal regions (i.e. premotor cortex and supplementary motor cortex), subcortical regions (i.e. hippocampus and caudate), temporal regions (i.e. inferior temporal gyrus and parahippocampal gyrus) and calcarine cortex. Three of these regions (i.e. premotor cortex, supplementary motor cortex and hippocampus) were related to better academic performance (β ranging from 0.211 to 0.352; all P < 0.05). Higher speed-agility was associated with greater gray matter volumes (P < 0.001, k = 57) in 2 clusters (i.e. the inferior frontal gyrus and the superior temporal gyrus) with β ranging from 0.564 to 0.611. Both clusters were related to better academic performance (β ranging from 0.217 to 0.296; both P < 0.05). Muscular fitness was not independently associated with greater gray matter volume in any brain region. Furthermore, there were no statistically significant negative association between any component of physical fitness and gray matter volume in any region of the brain. In conclusion, cardiorespiratory fitness and speed-agility, but not muscular fitness, may independently be associated with greater volume of numerous cortical and subcortical brain structures; besides, some of these brain structures may be related to better academic performance. Importantly, the identified associations of fitness and gray matter volume were different for each fitness component. These findings suggest that increases in cardiorespiratory fitness and speed-agility may positively influence the development of distinctive brain regions and academic indicators, and thus counteract the harmful effect of overweight and obesity on brain structure during childhood.
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http://dx.doi.org/10.1016/j.neuroimage.2017.08.011DOI Listing
October 2017

Whole-Body Vibration Mimics the Metabolic Effects of Exercise in Male Leptin Receptor-Deficient Mice.

Endocrinology 2017 05;158(5):1160-1171

Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, Georgia 30912.

Whole-body vibration (WBV) has gained attention as a potential exercise mimetic, but direct comparisons with the metabolic effects of exercise are scarce. To determine whether WBV recapitulates the metabolic and osteogenic effects of physical activity, we exposed male wild-type (WT) and leptin receptor-deficient (db/db) mice to daily treadmill exercise (TE) or WBV for 3 months. Body weights were analyzed and compared with WT and db/db mice that remained sedentary. Glucose and insulin tolerance testing revealed comparable attenuation of hyperglycemia and insulin resistance in db/db mice following TE or WBV. Both interventions reduced body weight in db/db mice and normalized muscle fiber diameter. TE or WBV also attenuated adipocyte hypertrophy in visceral adipose tissue and reduced hepatic lipid content in db/db mice. Although the effects of leptin receptor deficiency on cortical bone structure were not eliminated by either intervention, exercise and WBV increased circulating levels of osteocalcin in db/db mice. In the context of increased serum osteocalcin, the modest effects of TE and WBV on bone geometry, mineralization, and biomechanics may reflect subtle increases in osteoblast activity in multiple areas of the skeleton. Taken together, these observations indicate that WBV recapitulates the effects of exercise on metabolism in type 2 diabetes.
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http://dx.doi.org/10.1210/en.2016-1250DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5460837PMC
May 2017

Physical Activity Interventions for Neurocognitive and Academic Performance in Overweight and Obese Youth: A Systematic Review.

Pediatr Clin North Am 2016 06;63(3):459-80

Department of Pediatrics, Georgia Prevention Institute, Medical College of Georgia, Augusta University, 1125 15th Street, HS-1711, Augusta, GA 30912, USA. Electronic address:

This article examines cognitive, academic, and brain outcomes of physical activity in overweight or obese youth, with attention to minority youth who experience health disparities. Physically active academic lessons may have greater immediate cognitive and academic benefits among overweight and obese children than normal-weight children. Quasi-experimental studies testing physical activity programs in overweight and obese youth show promise; a few randomized controlled trials including African Americans show efficacy. Thus, making academic lessons physically active may improve inhibition and attentiveness, particularly in overweight youngsters. Regular physical activity may be efficacious for improving neurologic, cognitive, and achievement outcomes in overweight or obese youth.
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http://dx.doi.org/10.1016/j.pcl.2016.02.004DOI Listing
June 2016

Passive Smoke Exposure and Its Effects on Cognition, Sleep, and Health Outcomes in Overweight and Obese Children.

Child Obes 2016 Apr 26;12(2):119-25. Epub 2016 Jan 26.

4 Department of Biostatistics and Epidemiology, Medical College of Georgia, Augusta University , Augusta, GA.

Background: Passive smoke exposure (PSE) may be a risk factor for childhood overweight and obesity and is associated with worse neurocognitive development, cognition, and sleep in children. The purpose of the study is to examine the effects of PSE on adiposity, cognition, and sleep in overweight and obese children using an objective measure of PSE.

Methods: Overweight or obese children (n = 222) aged 7-11 (9.4 ± 1.1 years; 58% black; 58% female; 85% obese) were recruited from schools near Augusta, Georgia, over the course of the school year from 2003-2006 for a clinical trial, with data analyzed in 2009-2010. Passive smoke exposure was measured with plasma cotinine. Health, cognitive, and sleep measures and parent report of smoke exposure were obtained.

Results: Overweight and obese children with PSE had greater overall and central adiposity than nonexposed overweight and obese children (p < 0.03). However, PSE was unrelated to prediabetes, insulin resistance, or visceral fat. PSE was linked to poorer cognitive scores (p < 0.04) independent of adiposity, but was not related to sleep-disordered breathing.

Conclusions: PSE is associated with fatness and poorer cognition in children. Tailored interventions that target multiple health risk factors including nutrition, physical activity, and tobacco use in children and families are needed to prevent adverse health outcomes related to tobacco use and obesity.
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http://dx.doi.org/10.1089/chi.2015.0083DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4817566PMC
April 2016

Antisaccade-related brain activation in children with attention-deficit/hyperactivity disorder--A pilot study.

Psychiatry Res 2015 Nov 3;234(2):272-9. Epub 2015 Oct 3.

Psychology Department, University of Georgia, Athens, GA, USA; Neuroscience Department, University of Georgia, Athens, GA, USA. Electronic address:

While antisaccade paradigms invoke circuitry associated with cognitive control and attention-deficit/hyperactivity disorder (ADHD), there is a dearth of functional magnetic resonance imaging (fMRI) investigations using antisaccade tasks among children with ADHD. Neural correlates associated with antisaccade performance were examined with fMRI in 11 children with ADHD (10 medicated) matched to 11 typically developing children. Significantly greater brain activation in regions in right dorsolateral prefrontal cortex and caudate nucleus was observed in children with ADHD relative to the control group. This pattern separated the children into their respective groups in a taxonomic manner. Sensitivity analyses probing comorbidity and medication-specific effects showed that results were consistent; however, the caudate nucleus difference was only detectable in the full sample, or in subsets with a more relaxed cluster threshold. Antisaccade performance did not significantly differ between the groups, perhaps as a result of greater brain activation or medication effects in the ADHD group. Thus, antisaccade paradigms may have sensitivity and specificity for the investigation of cognitive control deficits and associated neural correlates in ADHD, and may contribute towards the development of new treatment approaches for children with the disorder.
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http://dx.doi.org/10.1016/j.pscychresns.2015.10.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4663690PMC
November 2015

Independent Associations of Organized Physical Activity and Weight Status with Children's Cognitive Functioning: A Matched-Pairs Design.

Pediatr Exerc Sci 2015 Nov 6;27(4):477-87. Epub 2015 Aug 6.

Medical College of Georgia, Augusta GA.

Purpose: This study tested whether participation in organized physical activity (active vs. inactive) or weight status (normal weight vs. overweight or obese) independently relate to children's cognition, using a matched-pairs design.

Design And Methods: Normal weight, active children (8-11 yrs, 5th-75th percentile BMI) were recruited from extracurricular physical activity programs while normal weight inactive (5th-75th percentile BMI) and overweight inactive children (BMI ≥85th percentile) were recruited from local Augusta, Georgia area schools. Measures included the Cognitive Assessment System, anthropometrics, and parent- and self-report of physical activity. Paired t tests compared cognition scores between matched groups of normal weight active vs. normal weight inactive (N = 24 pairs), normal weight inactive vs. overweight inactive (N = 21 pairs), and normal weight active vs. overweight inactive children (N = 16 pairs). Children in each comparison were matched for race, gender, age, and socioeconomic status.

Results: Normal weight active children had higher Planning (M± SD = 109 ± 11 vs. 100 ± 11, p = .011) and Attention scores (108 ± 11 vs. 100 ± 11, p = .013) than overweight inactive children. Normal weight inactive children had higher Attention scores than overweight inactive children (105 ± 13 vs. 93 ± 12, p = .008). When compared with normal weight inactive children, normal weight active children had higher Planning (113 ± 10 vs. 102 ± 13, p = .008) and marginally higher Attention scores (111 ± 11 vs. 104 ± 12, p = .06).

Conclusion: Findings suggest independent associations of children's weight status with selective attention, and physical activity with higher-order processes of executive function.
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http://dx.doi.org/10.1123/pes.2015-0044DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4698165PMC
November 2015

Society of Behavioral Medicine position statement: elementary school-based physical activity supports academic achievement.

Transl Behav Med 2014 Dec;4(4):436-8

University of South Carolina, Columbia, SC USA.

The Society of Behavioral Medicine (SBM) urges elementary schools to provide children with ample opportunities to engage in physical activity during school hours. In addition to promoting overall child health, physical activity also supports academic achievement. In addition to improving their aerobic fitness, regular physical activity improves cognitive function, influences the brain, and improves mood in children. Better aerobic fitness and physical activity are associated with increased grade point averages and standardized test scores. Despite the documented relationship between physical activity, fitness, and academic achievement, few schools have implemented physical activity as a tool to improve academic performance. SBM recommends that elementary schools provide children with the recommended 60 min of moderate-to-vigorous physical activity during school hours. Further, SBM urges schools to work with the local school districts and state education departments to mandate minimum physical activity time for elementary school physical education.
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http://dx.doi.org/10.1007/s13142-014-0279-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4286548PMC
December 2014

The relationship between uncinate fasciculus white matter integrity and verbal memory proficiency in children.

Neuroreport 2014 Aug;25(12):921-5

Departments of aNeuroscience bPsychology cComputer Science, University of Georgia, Athens, Georgia Departments of dRadiology ePediatrics and Georgia Prevention Center, Medical College of Georgia, Georgia Regents University, Augusta, Georgia, USA.

During childhood, verbal learning and memory are important for academic performance. Recent functional MRI studies have reported on the functional correlates of verbal memory proficiency, but few have reported the underlying structural correlates. The present study sought to test the relationship between fronto-temporal white matter integrity and verbal memory proficiency in children. Diffusion weighted images were collected from 17 Black children (age 8-11 years) who also completed the California Verbal Learning Test. To index white matter integrity, fractional anisotropy values were calculated for bilateral uncinate fasciculus. The results revealed that low anisotropy values corresponded to poor verbal memory, whereas high anisotropy values corresponded to significantly better verbal memory scores. These findings suggest that a greater degree of myelination and cohesiveness of axonal fibers in uncinate fasciculus underlie better verbal memory proficiency in children.
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http://dx.doi.org/10.1097/WNR.0000000000000204DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4107309PMC
August 2014

An 8-month exercise intervention alters frontotemporal white matter integrity in overweight children.

Psychophysiology 2014 Aug 5;51(8):728-33. Epub 2014 May 5.

Department of Neuroscience, University of Georgia, Athens, Georgia, USA.

In childhood, excess adiposity and low fitness are linked to poor academic performance, lower cognitive function, and differences in brain structure. Identifying ways to mitigate obesity-related alterations is of current clinical importance. This study examined the effects of an 8-month exercise intervention on the uncinate fasciculus, a white matter fiber tract connecting frontal and temporal lobes. Participants consisted of 18 unfit, overweight 8- to 11-year-old children (94% Black) who were randomly assigned to either an aerobic exercise (n = 10) or a sedentary control group (n = 8). Before and after the intervention, all subjects participated in a diffusion tensor MRI scan. Tractography was conducted to isolate the uncinate fasciculus. The exercise group showed improved white matter integrity as compared to the control group. These findings are consistent with an emerging literature suggesting beneficial effects of exercise on white matter integrity.
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http://dx.doi.org/10.1111/psyp.12227DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4107135PMC
August 2014

Endothelial health in childhood acute lymphoid leukemia survivors: pilot evaluation with peripheral artery tonometry.

J Pediatr Hematol Oncol 2015 Mar;37(2):117-20

*Division of Pediatric Oncology, School of Medicine, Bloomberg Children's Center, Johns Hopkins University ‡Department of Community-Public Health, School of Nursing, Johns Hopkins University, Baltimore, MD †Institute of Public and Preventive Health, Georgia Regents University, Augusta, GA.

Background: Childhood cancer survivors are a growing population at risk for poor cardiac outcomes. Acute lymphoid leukemia (ALL) survivors are among those at increased risk of cardiovascular complications. Early identification of impaired vascular health may allow for interventions to improve these outcomes. The purpose of this study was to evaluate vascular health using peripheral artery tonometry in ALL survivors and compare results with healthy siblings.

Procedure: Sixteen ALL survivor, healthy sibling pairs, aged 8 to 20 years, were evaluated for vascular health and cardiovascular risk factors (body mass index, central adiposity, blood pressure, and fitness). One-tailed paired t test was used to compare the groups.

Results: Survivors were similar to siblings in cardiovascular risk measures but had poorer vascular health as measured by reactive hyperemia index (survivor RHI 1.54 vs. sibling 1.77; P=0.0474).

Conclusion: This study reveals that even among survivors who are comparable to their healthy siblings in other traditional cardiovascular risks, there is evidence of poorer vascular health.
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http://dx.doi.org/10.1097/MPH.0000000000000122DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4145053PMC
March 2015

Obesity elicits interleukin 1-mediated deficits in hippocampal synaptic plasticity.

J Neurosci 2014 Feb;34(7):2618-31

Department of Physiology and Georgia Prevention Institute, Medical College of Georgia, Georgia Regents University, Augusta, Georgia 30912.

Adipose tissue is a known source of proinflammatory cytokines in obese humans and animal models, including the db/db mouse, in which obesity arises as a result of leptin receptor insensitivity. Inflammatory cytokines induce cognitive deficits across numerous conditions, but no studies have determined whether obesity-induced inflammation mediates synaptic dysfunction. To address this question, we used a treadmill training paradigm in which mice were exposed to daily training sessions or an immobile belt, with motivation achieved by delivery of compressed air on noncompliance. Treadmill training prevented hippocampal microgliosis, abolished expression of microglial activation markers, and also blocked the functional sensitization observed in isolated cells after ex vivo exposure to lipopolysaccharide. Reduced microglial reactivity with exercise was associated with reinstatement of hippocampus-dependent memory, reversal of deficits in long-term potentiation, and normalization of hippocampal dendritic spine density. Because treadmill training evokes broad responses not limited to the immune system, we next assessed whether directly manipulating adiposity through lipectomy and fat transplantation influences inflammation, cognition, and synaptic plasticity. Lipectomy prevents and fat transplantation promotes systemic and central inflammation, with associated alterations in cognitive and synaptic function. Levels of interleukin 1β (IL1β) emerged as a correlate of adiposity and cognitive impairment across both the treadmill and lipectomy studies, so we manipulated hippocampal IL1 signaling using intrahippocampal delivery of IL1 receptor antagonist (IL1ra). Intrahippocampal IL1ra prevented synaptic dysfunction, proinflammatory priming, and cognitive impairment. This pattern supports a central role for IL1-mediated neuroinflammation as a mechanism for cognitive deficits in obesity and diabetes.
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http://dx.doi.org/10.1523/JNEUROSCI.4200-13.2014DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3921429PMC
February 2014

Improved frontoparietal white matter integrity in overweight children is associated with attendance at an after-school exercise program.

Dev Neurosci 2014 21;36(1):1-9. Epub 2014 Jan 21.

Department of Psychology, University of Georgia, Athens, Ga., USA.

Aerobic fitness is associated with white matter integrity (WMI) in adults as measured by diffusion tensor imaging (DTI). This study examined the effect of an 8-month exercise intervention on WMI in children. Participants were 18 sedentary, overweight (BMI≥85th percentile) 8- to 11-year-old children (94% Black), randomly assigned to either an aerobic exercise (n=10) or sedentary attention control group (n=8). Each group was offered an instructor-led after-school program every school day for approximately 8 months. Before and after the program, all subjects participated in DTI scans. Tractography was conducted to isolate the superior longitudinal fasciculus and investigate whether the exercise intervention affected WMI in this region. There was no group by time interaction for WMI in the superior longitudinal fasciculus. There was a group by time by attendance interaction, however, such that higher attendance at the exercise intervention, but not the control intervention, was associated with increased WMI. Heart rate and the total dose of exercise correlated with WMI changes in the exercise group. In the overall sample, increased WMI was associated with improved scores on a measure of attention and improved teacher ratings of executive function. This study indicates that participating in an exercise intervention improves WMI in children as compared to a sedentary after-school program.
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http://dx.doi.org/10.1159/000356219DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3995327PMC
November 2014

A Test of Learned Industriousness in the Physical Activity Domain.

Int J Psychol Stud 2014;6(4):12-25

Department of Kinesiology & Nutrition, University of Illinois at Chicago.

Background: The Theory of Learned Industriousness states that durable individual differences in industriousness are due in part to differences in the extent to which individuals were rewarded for high effort at an earlier time. Individuals rewarded for high effort during training are thought to generalize greater persistence to subsequent tasks than those rewarded for low effort. This study tested whether rewarded physical and/or mental effort at different intensities generalized to greater persistence at a subsequent mental task.

Methods: 80 inactive 18-25 year-olds were randomized into four groups: Low Mental Effort, High Mental Effort, Low Physical Effort, and High Physical Effort. Each completed group-specific effort training and a mental persistence task at baseline and posttest.

Results: Factorial analysis of covariance revealed a significant interaction on persistence ([1,75]=4.93, =.029). High Mental Effort and Low Mental Effort groups demonstrated similar gains in persistence (-0.08, >.05) and points earned (=0.11, >.05) following effort training. High Physical Effort and Low Physical Effort diverged on persistence (=-0.49, =.004) but not points earned ( =-0.12, >.05).

Conclusions: Findings suggest either that training and test stimuli were too dissimilar to cue effects of associative learning in physical effort groups, or that effects were present but overpowered by the affective and neurocognitive consequences of an acute bout of intense aerobic physical activity. Findings do not support the Theory of Learned Industriousness nor generalization of effort across physical and mental domains.
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http://dx.doi.org/10.5539/ijps.v6n4p12DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4456027PMC
January 2014

An 8-month randomized controlled exercise trial alters brain activation during cognitive tasks in overweight children.

Obesity (Silver Spring) 2014 Jan 10;22(1):232-42. Epub 2013 Sep 10.

Psychology Department, University of Georgia, Athens, Georgia, USA.

Objective: Children who are less fit reportedly have lower performance on tests of cognitive control and differences in brain function. This study examined the effect of an exercise intervention on brain function during two cognitive control tasks in overweight children.

Design And Methods: Participants included 43 unfit, overweight (BMI ≥ 85th percentile) children 8- to 11-years old (91% Black), who were randomly divided into either an aerobic exercise (n = 24) or attention control group (n = 19). Each group was offered a separate instructor-led after-school program every school day for 8 months. Before and after the program, all children performed two cognitive control tasks during functional magnetic resonance imaging (fMRI): antisaccade and flanker.

Results: Compared to the control group, the exercise group decreased activation in several regions supporting antisaccade performance, including precentral gyrus and posterior parietal cortex, and increased activation in several regions supporting flanker performance, including anterior cingulate and superior frontal gyrus.

Conclusions: Exercise may differentially impact these two task conditions, or the paradigms in which cognitive control tasks were presented may be sensitive to distinct types of brain activation that show different effects of exercise. In sum, exercise appears to alter efficiency or flexible modulation of neural circuitry supporting cognitive control in overweight children.
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http://dx.doi.org/10.1002/oby.20518DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4077546PMC
January 2014

Oxidative stress and cardiovascular risk in overweight children in an exercise intervention program.

Child Obes 2013 Feb 27;9(1):15-21. Epub 2012 Dec 27.

Section of Endocrinology, Diabetes and Metabolism, Department of Medicine, Medical College of Georgia, Augusta, GA 30912, USA.

Background: This study aimed to determine whether oxidative stress was related to cardiovascular risk indices in children, and whether an exercise intervention would reduce oxidative stress.

Methods: A randomized trial of two different doses of exercise and a no-exercise control group included 112 overweight and obese children, 7-11 years old. Plasma isoprostane levels were obtained at baseline and after the intervention. Cross-sectional analysis of oxidative stress and metabolic markers at baseline was performed. The effect of the exercise training on oxidative stress was tested.

Results: Lower isoprostane levels were observed in blacks. At baseline, isoprostane was positively related to measures of fatness (BMI, waist circumference, percent body fat), insulin resistance and β-cell function (fasting insulin, insulin area under the curve, Matsuda index, disposition index, oral disposition index), and several lipid markers (low-density lipoprotein, triglycerides, total cholesterol), and inversely with fitness [peak oxygen consumption (VO(2))], independent of race, sex, and cohort. No relation was found with visceral fat, blood pressure, or glycemia. Independent of percent body fat, isoprostane predicted triglycerides, β=0.23, total cholesterol-to-high-density lipoprotein (TC/HDL) ratio, β=0.23, and insulin resistance (insulin area under the curve, β=0.24, Matsuda index, β=-0.21, oral disposition index, β=0.33). Exercise did not reduce oxidative stress levels, despite reduced fatness and improved fitness in these children.

Conclusions: Isoprostane levels were related to several markers of cardiovascular risk at baseline; however, despite reduced fatness and improved fitness, no effect of exercise was observed on isoprostane levels. To our knowledge, this is the first report in children to demonstrate a correlation of oxidative stress with disposition index, fitness, and TC/HDL ratio, the first to test the effect on oxidative stress of an exercise intervention that reduced body fat, and the first such exercise intervention study to include a substantial proportion of black children.
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http://dx.doi.org/10.1089/chi.2011.0092DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3621572PMC
February 2013

Exercise dose and diabetes risk in overweight and obese children: a randomized controlled trial.

JAMA 2012 Sep;308(11):1103-12

Georgia Prevention Center, Institute for Public and Preventive Health, Department of Pediatrics, Medical College of Georgia, 1120 15th St, Ste 1640, Augusta, GA 30912, USA.

Context: Pediatric studies have shown that aerobic exercise reduces metabolic risk, but dose-response information is not available.

Objectives: To test the effect of different doses of aerobic training on insulin resistance, fatness, visceral fat, and fitness in overweight, sedentary children and to test moderation by sex and race.

Design, Setting, And Participants: Randomized controlled efficacy trial conducted from 2003 through 2007 in which 222 overweight or obese sedentary children (mean age, 9.4 years; 42% male; 58% black) were recruited from 15 public schools in the Augusta, Georgia, area.

Intervention: Children were randomly assigned to low-dose (20 min/d; n = 71) or high-dose (40 min/d; n = 73) aerobic training (5 d/wk; mean duration, 13 [SD, 1.6] weeks) or a control condition (usual physical activity; n = 78).

Main Outcome Measures: The prespecified primary outcomes were postintervention type 2 diabetes risk assessed by insulin area under the curve (AUC) from an oral glucose tolerance test, aerobic fitness (peak oxygen consumption [VO2]), percent body fat via dual-energy x-ray absorptiometry, and visceral fat via magnetic resonance, analyzed by intention to treat.

Results: The study had 94% retention (n = 209). Most children (85%) were obese. At baseline, mean body mass index was 26 (SD, 4.4). Reductions in insulin AUC were larger in the high-dose group (adjusted mean difference, -3.56 [95% CI, -6.26 to -0.85] × 10(3) μU/mL; P = .01) and the low-dose group (adjusted mean difference, -2.96 [95% CI, -5.69 to -0.22] × 10(3) μU/mL; P = .03) than the control group. Dose-response trends were also observed for body fat (adjusted mean difference, -1.4% [95% CI, -2.2% to -0.7%]; P < .001 and -0.8% [95% CI, -1.6% to -0.07%]; P = .03) and visceral fat (adjusted mean difference, -3.9 cm3 [95% CI, -6.0 to -1.7 cm3]; P < .001 and -2.8 cm3 [95% CI, -4.9 to -0.6 cm3]; P = .01) in the high- and low-dose vs control groups, respectively. Effects in the high- and low-dose groups vs control were similar for fitness (adjusted mean difference in peak VO2, 2.4 [95% CI, 0.4-4.5] mL/kg/min; P = .02 and 2.4 [95% CI, 0.3-4.5] mL/kg/min; P = .03, respectively). High- vs low-dose group effects were similar for these outcomes. There was no moderation by sex or race.

Conclusion: In this trial, after 13 weeks, 20 or 40 min/d of aerobic training improved fitness and demonstrated dose-response benefits for insulin resistance and general and visceral adiposity in sedentary overweight or obese children, regardless of sex or race.

Trial Registration: clinicaltrials.gov Identifier: NCT00108901.
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http://dx.doi.org/10.1001/2012.jama.10762DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3487697PMC
September 2012

Greater fructose consumption is associated with cardiometabolic risk markers and visceral adiposity in adolescents.

J Nutr 2012 Feb 21;142(2):251-7. Epub 2011 Dec 21.

Department of Pediatrics, Georgia Health Sciences University, Augusta, GA, USA.

Though adolescents consume more fructose than any other age group, the relationship between fructose consumption and markers of cardiometabolic risk has not been established in this population. We determined associations of total fructose intake (free fructose plus one-half the intake of free sucrose) with cardiometabolic risk factors and type of adiposity in 559 adolescents aged 14-18 y. Fasting blood samples were measured for glucose, insulin, lipids, adiponectin, and C-reactive protein. Diet was assessed with 4-7 24-h recalls and physical activity (PA) was determined by accelerometry. Fat-free soft tissue (FFST) mass and fat mass were measured by DXA. The s.c. abdominal adipose tissue (SAAT) and visceral adipose tissue (VAT) were assessed using MRI. Multiple linear regression, adjusting for age, sex, race, Tanner stage, FFST mass, fat mass, PA, energy intake, fiber intake, and socioeconomic status, revealed that fructose intake was associated with VAT (β = 0.13; P = 0.03) but not SAAT (P = 0.15). Significant linear upward trends across tertiles of fructose intake were observed for systolic blood pressure, fasting glucose, HOMA-IR, and C-reactive protein after adjusting for the same covariates (all P-trend < 0.04). Conversely, significant linear downward trends across tertiles of fructose intake were observed for plasma HDL-cholesterol and adiponectin (both P-trend < 0.03). When SAAT was added as a covariate, these trends persisted (all P-trend < 0.05). However, when VAT was included as a covariate, it attenuated these trends (all P-trend > 0.05). In adolescents, higher fructose consumption is associated with multiple markers of cardiometabolic risk, but it appears that these relationships are mediated by visceral obesity.
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http://dx.doi.org/10.3945/jn.111.150219DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3260058PMC
February 2012

Lower uncarboxylated osteocalcin concentrations in children with prediabetes is associated with beta-cell function.

J Clin Endocrinol Metab 2011 Jul 20;96(7):E1092-9. Epub 2011 Apr 20.

Department of Pediatrics, Georgia Prevention Institute, Georgia Health Sciences University, Augusta, Georgia 30912, USA.

Context: Although animal studies suggest that it is the uncarboxylated rather than carboxylated form of osteocalcin that affects glucose homeostasis, the human data are scant and equivocal.

Objective: This study investigated associations of uncarboxylated and carboxylated forms of osteocalcin with insulin sensitivity and β-cell function in 140 overweight prepubertal children (43% female, 46% black, 84% obese) with normal glucose levels (n = 99) and prediabetes (n = 41).

Methods: An oral glucose tolerance test was used to identify prediabetes and for measurement of insulin sensitivity (Matsuda index), β-cell function [oral glucose tolerance test derived insulinogenic index and disposition index (DI(OGTT))] and uncarboxylated and carboxylated forms of osteocalcin. Visceral adipose tissue (VAT) was assessed using magnetic resonance imaging.

Results: After controlling for age, sex and race, lower uncarboxylated osteocalcin concentrations, Matsuda index, insulinogenic index, and DI(OGTT) and higher VAT levels were found in the prediabetes vs. normal-glucose group (all P < 0.03). Carboxylated osteocalcin levels were not different between groups. Multiple linear regression adjusting for age, sex, race, and VAT revealed that uncarboxylated osteocalcin was associated with insulinogenic index and DI(OGTT) (β = 0.34, 0.36, respectively, both P < 0.04) in the prediabetes group but not the normal-glucose group. In both the normal-glucose and prediabetes groups, carboxylated osteocalcin was associated with insulin sensitivity (β = 0.26, 0.47, respectively, both P < 0.02).

Conclusions: These data suggest that the lower uncarboxylated osteocalcin concentrations found in children with prediabetes may be associated with β-cell dysfunction. In addition, our findings between carboxylated osteocalcin and insulin sensitivity suggest that carboxylated osteocalcin plays a role in human glucose homeostasis.
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http://dx.doi.org/10.1210/jc.2010-2731DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3135188PMC
July 2011

Exercise improves executive function and achievement and alters brain activation in overweight children: a randomized, controlled trial.

Health Psychol 2011 Jan;30(1):91-8

Georgia Prevention Institute, Pediatrics, Medical College of Georgia, Augusta, GA 30912, USA.

Objective: This experiment tested the hypothesis that exercise would improve executive function.

Design: Sedentary, overweight 7- to 11-year-old children (N = 171, 56% girls, 61% Black, M ± SD age = 9.3 ± 1.0 years, body mass index [BMI] = 26 ± 4.6 kg/m², BMI z-score = 2.1 ± 0.4) were randomized to 13 ± 1.6 weeks of an exercise program (20 or 40 min/day), or a control condition.

Main Outcome Measures: Blinded, standardized psychological evaluations (Cognitive Assessment System and Woodcock-Johnson Tests of Achievement III) assessed cognition and academic achievement. Functional MRI measured brain activity during executive function tasks.

Results: Intent to treat analysis revealed dose-response benefits of exercise on executive function and mathematics achievement. Preliminary evidence of increased bilateral prefrontal cortex activity and reduced bilateral posterior parietal cortex activity attributable to exercise was also observed.

Conclusion: Consistent with results obtained in older adults, a specific improvement on executive function and brain activation changes attributable to exercise were observed. The cognitive and achievement results add evidence of dose-response and extend experimental evidence into childhood. This study provides information on an educational outcome. Besides its importance for maintaining weight and reducing health risks during a childhood obesity epidemic, physical activity may prove to be a simple, important method of enhancing aspects of children's mental functioning that are central to cognitive development. This information may persuade educators to implement vigorous physical activity.
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http://dx.doi.org/10.1037/a0021766DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3057917PMC
January 2011

Fitness, fatness, cognition, behavior, and academic achievement among overweight children: do cross-sectional associations correspond to exercise trial outcomes?

Prev Med 2011 Jun 31;52 Suppl 1:S65-9. Epub 2011 Jan 31.

Georgia Prevention Institute, Department of Pediatrics, Medical College of Georgia, Georgia Health Sciences University, 1499 Walton Way, HS1711, Augusta, GA 30912, USA.

Background: This study examined associations of fitness and fatness with cognitive processes, academic achievement, and behavior, independent of demographic factors, at the baseline of an exercise trial.

Methods: Overweight, sedentary but otherwise healthy 7-11 year olds (N=170) participated in a study of health, cognition and achievement in the Augusta, GA area from 2003-2006. Children underwent evaluations of fatness and fitness, psychological assessments of cognition and academic achievement, and behavior ratings by parents and teachers. Partial correlations examined associations of fitness and fatness with cognitive and achievement scores and behavior ratings, controlling for demographic factors.

Results: Fitness was associated with better cognition, achievement and behavior, and fatness with worse scores. Specifically, executive function, mathematics and reading achievement, and parent ratings of child behavior were related to fitness and fatness. Teacher ratings were related to fitness.

Conclusion: These results extend prior studies by providing reliable, standardized measures of cognitive processes, achievement, and behavior in relation to detailed measures of fitness and fatness. However, cross-sectional associations do not necessarily indicate that improving one factor, such as fatness or fitness, will result in improvements in factors that were associated with it. Thus, randomized clinical trials are necessary to determine the effects of interventions.
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http://dx.doi.org/10.1016/j.ypmed.2011.01.020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3164323PMC
June 2011

Adolescent obesity, bone mass, and cardiometabolic risk factors.

J Pediatr 2011 May 13;158(5):727-34. Epub 2011 Jan 13.

Department of Pediatrics, Medical College of Georgia, Augusta, GA 30912, USA.

Objective: To compare bone mass between overweight adolescents with and without cardiometabolic risk factors (CMR). Associations of bone mass with CMR and adiposity were also determined.

Study Design: Adolescents (aged 14 to 18 years) who were overweight were classified as healthy (n = 55), having one CMR (1CMR; n = 46), or having two or more CMR (≥2CMR; n = 42). CMRs were measured with standard methods and defined according to pediatric definitions of metabolic syndrome. Total body bone mass, fat mass, and fat-free soft tissue mass were measured with dual-energy X-ray absorptiometry. Visceral adipose tissue and subcutaneous abdominal adipose tissue were assessed with magnetic resonance imaging.

Results: After controlling for age, sex, race, height, and fat-free soft tissue mass, the healthy group had 5.4% and 6.3% greater bone mass than the 1CMR and ≥2CMR groups, respectively (both P values <.04). With multiple linear regression, adjusting for the same co-variates, visceral adipose tissue (β = -0.22), waist circumference (β = -0.23), homeostasis model assessment of insulin resistance (β = -0.23), and high-density lipoprotein cholesterol level (β = 0.22) were revealed to be associated with bone mass (all P values <.04). There was a trend toward a significant inverse association between bone mass and fasting glucose level (P = .056). No relations were found between bone mass and fat mass, subcutaneous abdominal adipose tissue, blood pressure, or triglyceride level.

Conclusion: Being overweight with metabolic abnormalities, particularly insulin resistance, low high-density lipoprotein cholesterol level, and visceral adiposity, may adversely influence adolescent bone mass.
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http://dx.doi.org/10.1016/j.jpeds.2010.11.052DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3383822PMC
May 2011

Leukocyte telomere length in healthy Caucasian and African-American adolescents: relationships with race, sex, adiposity, adipokines, and physical activity.

J Pediatr 2011 Feb 19;158(2):215-20. Epub 2010 Sep 19.

Department of Pediatrics, Georgia Prevention Institute, Medical College of Georgia, Augusta, GA 30912-3715, USA.

Objective: To examine the relationships of race, sex, adiposity, adipokines, and physical activity to telomere length in adolescents.

Study Design: Leukocyte telomere length (T/S ratio) was assessed cross-sectionally in 667 adolescents (aged 14-18 years; 48% African-Americans; 51% girls) using a quantitative polymerase chain reaction method. Generalized estimating equations analyses were performed.

Results: Telomere length was greater in the African-American adolescents than in the Caucasian adolescents (age- and sex-adjusted T/S ratio ± SE, 1.32 ± 0.01 vs 1.27 ± 0.01: P = .014) and greater in girls than in boys (age- and race-adjusted T/S ratio ± SE, 1.31 ± 0.01 vs 1.27 ± 0.01; P = .007). None of the adiposity or adipokine measures explained a significant proportion of the variance in telomere length. Vigorous physical activity was positively associated with telomere length (adjusted R(2) = 0.019; P = .009) and accounted for 1.9% of the total variance only in girls.

Conclusions: This study, conducted in a biracial adolescent cohort, demonstrated that (1) race and sex differences in telomere length have already emerged during adolescence; (2) adiposity and adipokines are not associated with telomere length at this age; and (3) the antiaging effect of vigorous physical activity may begin in youth, especially in girls.
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http://dx.doi.org/10.1016/j.jpeds.2010.08.007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3010324PMC
February 2011