Benefits for African American and white low-income 7-10-year-old children and their parents taught together in a community-based weight management program in the rural southeastern United States.

BACKGROUND: Low-income children and parents are at increased risk for developing overweight and obesity. Therefore, the purpose of this exploratory study was to compare whether African American and white children and parents benefitted equally from a community-based weight management intervention delivered in two rural counties in southeastern North Carolina (N.C.). METHODS: We compared the efficacy of the Family Partners for Health intervention for African American and white children and their parents by testing the three-way interaction of the intervention group according to visit and race. RESULTS: African American children in the intervention group weighed significantly (P = 0.027) less than those in the control group, while white children in the intervention group weighed less than those in the control group, but the difference did not reach statistical significance. African American and white parents in the intervention group weighed less than their respective control groups across all three data collections, but the difference was only significant in the group of white parents (P = 0.010) at the completion of the study. At the completion of the study, African American children in the intervention group received significantly (P = 0.003) more support for physical activity than African American children in the control group. At both time points, white children in the intervention group were not significantly different from those in the control group. African American parents in the intervention group scored slightly worse in the stress management assessment compared to those in the control group, while white parents in the intervention group showed a significantly (P = 0.041) better level of stress management than those in the control group. At the completion of the study, African American parents in the intervention group scored somewhat worse in emotional eating self-efficacy compared to the scores of the African American parents in the control group, while white parents in the intervention group scored significantly (P < 0.001) better than those in the control group. CONCLUSIONS: We were successful in affecting some outcomes in both African American and white children and parents using the same intervention. TRIAL REGISTRATION: NCT01378806 Registered June 22, 2011.

Ventilatory Responses During Submaximal Exercise in Children With Prader-Willi Syndrome.

PURPOSE: Prader-Willi syndrome (PWS) is a genetic neurobehavioral disorder presenting hypothalamic dysfunction and adiposity. At rest, PWS exhibits hypoventilation with hypercapnia. We characterized ventilatory responses in children with PWS during exercise. METHODS: Participants were children aged 7-12 years with PWS (n = 8) and without PWS with normal weight (NW; n = 9, body mass index ≤ 85th percentile) or obesity (n = 9, body mass index ≥ 95th percentile). Participants completed three 5-minute ambulatory bouts at 3.2, 4.0, and 4.8 km/h. Oxygen uptake, carbon dioxide output, ventilation, breathing frequency, and tidal volume were recorded. RESULTS: PWS had slightly higher oxygen uptake (L/min) at 3.2 km/h [0.65 (0.46-1.01) vs 0.49 (0.34-0.83)] and at 4.8 km/h [0.89 (0.62-1.20) vs 0.63 (0.45-0.97)] than NW. PWS had higher ventilation (L/min) at 3.2 km/h [16.2 (13.0-26.5) vs 11.5 (8.4-17.5)], at 4.0 km/h [16.4 (13.9-27.9) vs 12.7 (10.3-19.5)], and at 4.8 km/h [19.7 (17.4-31.8) vs 15.2 (9.5-21.6)] than NW. PWS had greater breathing frequency (breaths/min) at 3.2 km/h [38 (29-53) vs 29 (22-35)], at 4.0 km/h [39 (29-58) vs 29 (23-39)], and at 4.8 km/h [39 (33-58) vs 32 (23-42)], but similar tidal volume and ventilation/carbon dioxide output to NW. CONCLUSION: PWS did not show impaired ventilatory responses to exercise. Hyperventilation in PWS may relate to excessive neural stimulation and metabolic cost.

Energy Cost Expression for a Youth Compendium of Physical Activities: Rationale for Using Age Groups.

PURPOSE: This study compared the accuracy of physical activity energy expenditure (PAEE) prediction using 2 methods of accounting for age dependency versus 1 standard (single) value across all ages. METHODS: PAEE estimates were derived by pooling data from 5 studies. Participants, 6-18 years (n = 929), engaged in 14 activities while in a room calorimeter or wearing a portable metabolic analyzer. Linear regression was used to estimate the measurement error in PAEE (expressed as youth metabolic equivalent) associated with using age groups (6-9, 10-12, 13-15, and 16-18 y) and age-in-years [each year of chronological age (eg, 12 = 12.0-12.99 y)] versus the standard (a single value across all ages). RESULTS: Age groups and age-in-years showed similar error, and both showed less error than the standard method for cycling, skilled, and moderate- to vigorous-intensity activities. For sedentary and light activities, the standard had similar error to the other 2 methods. Mean values for root mean square error ranged from 0.2 to 1.7 youth metabolic equivalent across all activities. Error reduction ranged from -0.2% to 21.7% for age groups and -0.23% to 18.2% for age-in-years compared with the standard. CONCLUSIONS: Accounting for age showed lower errors than a standard (single) value; using an age-dependent model in the Youth Compendium is recommended.

The influence of physical characteristics on the resting energy expenditure of youth: A meta-analysis.

OBJECTIVE: To examine the literature on resting energy expenditure (REE) of youth and determine the influence of age, sex, BMI, and body composition on REE. METHODS: A literature search was conducted using PubMed, BIOSIS Previews, NTIS, EMBASE, MEDLINE, and Pascal databases for studies with data on resting metabolic rate, REE, resting oxygen uptake (or VO2 ) in healthy children, youth, or adolescents (age = 1-18 years). Over 200 publications were identified; sixty-one publications met criteria and were included in the meta-analyses, resulting in 142 study population estimates (totaling 5,397 youth) of REE. RESULTS: Pooled mean was 1414 kcal·day-1 with a significant and moderate-to-high between-study heterogeneity [Q(140) = 7912.42, P < 0.001; I2 = 98.97%]. A significantly greater (P < 0.001) pooled mean kcal·day-1 was estimated for studies with male participants (1519 kcal·day-1 ) comparing to studies with female participants (1338 kcal·day-1 ). Age, height, and body mass resulted in the highest R2 of 86.4 for males and 83.9% for females. Fat free mass and body mass index (BMI) did not improve total R2 . CONCLUSIONS: These data suggest that using a linear equation including age, height, and body mass to estimate REE based on kcal·day-1 is more accurate than estimates based on body mass kcal·kg-1 ·h-1 . Further, if kcal·kg-1 ·h-1 is used, including a quadratic component for the physical characteristics improves the predictive ability of the equation. Regardless of the metric, separate equations should be used for each sex.

Relationships of physical activity and sedentary time in obese parent-child dyads: a cross-sectional study.

BACKGROUND: Research suggests physical activity is linked to obesity. Further, the physical activity of healthy parents and their children is associated with each other. However, this relationship has not been examined in obese parents and their obese children. METHODS: The purpose of this study was to compare the physical activity and sedentary time of obese, low-income, ethnic minority parents and their children on weekdays and weekend days using accelerometry. Data were obtained from eight rural sites in the middle and eastern part of North Carolina (N.C.), United States (U.S.) from 2007-2010 using a rolling enrollment. One hundred and ninety-nine obese parents (94 % female) and their obese children (54 % female) wore accelerometers simultaneously for three weekdays and one weekend day. Total physical activity, moderate-to-vigorous physical activity (MVPA) and sedentary time and proportions were determined. RESULTS: Parents' and children's total physical activity and MVPA levels were lower on weekend days than weekdays. Total counts per minute for children on weekdays and weekend days were greater than for parents (p < 0.001). Total counts per minute were more highly correlated on weekend days than weekdays (r = 0.352, p < 0.0002 versus r = 0.165, p < 0.025). Parents' performed MVPA for 14 (SD = ±25) and 9 (SD = ±16) minutes/day on weekdays and weekend days, respectively; children performed MVPA for 37 (SD = ±25) and 31(SD = ±38) minutes/day for weekdays and weekend days, respectively. Correlations between parents and children for MVPA were higher on weekend days versus weekdays (r = 0.253 and 0.177, respectively; p < 0.015). Associations for sedentary time followed a similar trend, with r = 0.33 (p < 0.0002) for weekend days and r = 0.016 (p < 0.026) for weekdays. Associations between obese parent-child dyads on sedentary time were stronger for girls, while associations between dyads on MVPA were stronger for boys. However, formal interaction analyses were not significant (p > 0.13). DISCUSSION: Since physical activity levels of obese parents and their obese child are somewhat related, especially on weekend days, combined parent-child obesity programs focused on reducing sedentary time could be beneficial, particularly for the child. CONCLUSION: In conclusion, this study of the physical activity levels of obese parents and their obese children found some relationships between the parents' and children's physical activity and sedentary behavior patterns, especially on weekend days. TRIAL REGISTRATION: NCT01378806 .

Insights into physical activity and cardiovascular disease risk in young children: IDEFICS study.

The association between physical activity and cardiovascular disease risk factors in children has been the focus of research for over two decades. The majority of this research has focused on children over 10 years of age with little information on very young children. The data recently published in BMC Medicine by Jiménez-Pavón and colleagues suggest that adverse cardiovascular disease (CVD) risk profiles, as indicated by a clustered risk score for the metabolic syndrome, are evident in very young children (two to six years of age), but differ between the sexes. The authors evaluated the relationship of CVD risk profiles and protective levels of moderate-to-vigorous physical activity (MVPA) and concluded that boys aged six years or younger needed >60 minutes of MVPA per day, whereas boys from six to nine years of age needed >80 minutes of MVPA per day; girls in either age group needed approximately 15 minutes less. Therefore, when clinicians recommend physical activity for children they should evaluate "at risk" children on a case-by-case basis rather than using generalized guidelines.

Tracking of clustered cardiovascular disease risk factors from childhood to adolescence.

BACKGROUND: Clustering of cardiovascular disease (CVD) risk factors has been found in children as young as 9 y of age. However, the stability of this clustering over the course of childhood has yet to be determined. The purpose of this study was to determine the tracking of clustered CVD risk from young school age through adolescence and to examine differences in tracking between levels of overweight/obesity and cardiorespiratory fitness (VO(2peak)). METHODS: Beginning at 6 y, children (n = 434) were measured three times in 7 y. Anthropometrics, blood pressure, and VO(2peak) were measured. Fasting blood samples were analyzed for CVD risk factors. A clustered risk score (z-score) was constructed by adding sex-specific z-scores for blood pressure, homeostatic model assessment (HOMA-IR), triglyceride (TG), skinfolds, and negative values of high-density lipoprotein cholesterol (HDLc) and VO(2peak). RESULTS: Significant tracking coefficients were found between clustered z-score at all time intervals (r = 0.514, 0.559, and 0.381 between ages 6-9, 9-13, and 6-13 y, respectively, all P < 0.0001). Tracking was higher for low-fit children, whereas no clear pattern was found for different levels of body fat. CONCLUSION: We found that clustered z-score is a fairly stable characteristic through childhood. Implementation of preventive strategies could therefore start at early school age.

BMI change, fitness change and cardiometabolic risk factors among 8th grade youth.

This paper examined whether a two-year change in fitness, body mass index (BMI) or the additive effect of change in fitness and BMI were associated with change in cardiometabolic risk factors among youth. Cardiometabolic risk factors, BMI group (normal weight, overweight or obese) were obtained from participants at the start of 6th grade and end of 8th grade. Shuttle run laps were assessed and categorized in quintiles at both time points. Regression models were used to examine whether changes in obesity, fitness or the additive effect of change in BMI and fitness were associated with change in risk factors. There was strong evidence (p < .001) that change in BMI was associated with change in cardiometabolic risk factors. There was weaker evidence of a fitness effect, with some evidence that change in fitness was associated with change in total cholesterol, HDL-C, LDL-C and clustered risk score among boys, as well as HDL-C among girls. Male HDL-C was the only model for which there was some evidence of a BMI, fitness and additive BMI*fitness effect. Changing body mass is central to the reduction of youth cardiometabolic risk. Fitness effects were negligible once change in body mass had been taken into account.

Assessing explosive power production using the backward overhead shot throw and the effects of morning resistance exercise on afternoon performance.

The purpose of this study was to determine if performing a morning total-body resistance exercise workout affects explosive power in an afternoon session. The secondary goal was to assess the usefulness of the backward overhead shot throw (BOST) as a measure of explosive power in experienced thrower in the sport of athletics. Throwers (N = 14) performed 1 control and 1 experimental trial on separate days. The control consisted of BOST and a vertical jump (VJ) testing performed in the afternoon. For the experimental trial, the participants reported for a short resistance training session in the morning then repeating the BOST and VJ testing 4-6 hours later. The BOST distance (meters) and VJ peak power (watts) were correlated in both trials (r ∼ 0.64, p < 0.05). The BOST distance improved in experimental trial over control (p < 0.05), but VJ power failed to improve. The results indicate that a morning resistance exercise bout can improve competitive throwing performance later on the same day. The results also suggest that BOST may be a useful performance testing tool for throwers in the sports of athletics.

Recruitment and retention strategies for a community-based weight management study for multi-ethnic elementary school children and their parents.

This article describes successful recruitment and retention strategies for a community-based weight management study in two school districts in North Carolina. Recruitment and retention on both district and school levels and child and parent levels are discussed. A total of 358 children and 358 parents from eight schools in rural North Carolina participated in a randomized controlled trial to test the effectiveness of a nutrition and exercise education, coping skills training, and exercise intervention. Recruitment and retention at the district and school level included meeting with superintendents and receiving a proper introduction to school principals and consistently clear communication throughout the study. At the school level, relationships were developed with the principal and other key personnel to keep lines of communication open during the study. Recruitment and retention strategies at the child and parent level included allowing adequate time for questions during consent and assent and providing a free nutrition and exercise program, a light meal, homework assistance, child care for other children who came to the program, and transportation vouchers if needed. Successful recruitment and retention strategies at the district and school levels and child and parent levels are important for conducting longitudinal community-based studies.

Process evaluation results from the HEALTHY physical education intervention.

Process evaluation is an assessment of the implementation of an intervention. A process evaluation component was embedded in the HEALTHY study, a primary prevention trial for Type 2 diabetes implemented over 3 years in 21 middle schools across the United States. The HEALTHY physical education (PE) intervention aimed at maximizing student engagement in moderate-to-vigorous physical activity through delivery of structured lesson plans by PE teachers. Process evaluation data collected via class observations and interventionist interviews assessed fidelity, dose delivered, implementor participation, dose received and barriers. Process evaluation results indicate a high level of fidelity in implementing HEALTHY PE activities and offering 225 min of PE every 10 school days. Concerning dose delivered, students were active for approximately 33 min of class, representing an average of 61% of the class time. Results also indicate that PE teachers were generally engaged in implementing the HEALTHY PE curriculum. Data on dose received showed that students were highly engaged with the PE intervention; however, student misbehavior was the most common barrier observed during classes. Other barriers included teacher disengagement, large classes, limited gym space and poor classroom management. Findings suggest that the PE intervention was generally implemented and received as intended despite several barriers.

Validity of self-reported leisure-time sedentary behavior in adolescents.

BACKGROUND: To evaluate the concordance between leisure-time sedentary behavior in adolescents assessed by an activity-based questionnaire and accelerometry. A convenience sample of 128 girls and 73 boys, 11-15 years of age (12.6 ± 1.1 years) from six states across the United States examined as part of the feasibility studies for the Trial of Activity in Adolescent Girls (TAAG). Three days of self-reported time spent watching TV/videos, using computers, playing video/computer games, and talking on the phone was assessed using a modified version of the Self-Administered Physical Activity Checklist (SAPAC). Criterion measure of sedentary behavior was via accelerometry over three days using a cut point of < 50 counts · 30 sec⁻¹ epoch. Comparisons between sedentary behavior by the two instruments were made. RESULTS: Adolescents generally underestimated minutes of sedentary behavior compared to accelerometry-measured minutes. The overall correlation between minutes of sedentary behavior by self-report and accelerometry was weak (Spearman r = 0.14; 95% CI 0.05, 0.23). Adjustment of sedentary minutes of behavior for total minutes assessed using either percentages or the residuals method tended to increase correlations slightly. However, regression analyses showed no significant association between self-reported sedentary behavior and minutes of sedentary behavior captured via accelerometry. DISCUSSION: These findings suggest that the modified 3-day Self-Administered Physical Activity Checklist is not a reliable method for assessing sedentary behavior. It is recommended that until validation studies for self-report instruments of sedentary behavior demonstrate validity, objective measures should be used.

Effects of being overweight on ventilatory dynamics of youth at rest and during exercise.

Research on obese adults has shown that their ventilatory dynamics differ from normal weight adults; however, the ventilatory dynamics of obese and non-obese children have never been documented. Thus, the ventilatory responses of 73 overweight youth (BMI >85th percentile) were compared to 73 age, sex and height-matched normal weight youth (BMI <85th percentile), during 15 min of rest and steady-state exercise at 4, 5.6 and 8 kph. Overweight youth had higher oxygen uptakes (VO2 mL/min), ventilation (VE), tidal volume (V (T)), frequency (f (R)), physiological dead air space (V (D)) and V (D)/V (T) ratios than normal weight youth (P < 0.02); however, end-tidal CO(2) (P(ET)CO(2)), VE/VO2 and VE/VCO2 were similar. Inspiratory drive (V (T)/t (i)) was greater for overweight youth at rest and during exercise. The correlation between P(ET)CO(2) and inspiratory drive was significant for the overweight group at 5.6 and 8 kph (r = 0.23-0.44), but not significant for the normal weight youth (r = -0.04 to 0.10). The greater drive, respiratory frequency and physiologic dead air space of overweight youth suggest that their adiposity modifies ventilation dynamics during exercise. However, the modifications appear to meet the metabolic demands of exercise.

The interaction of obesity and puberty on substrate utilization during exercise: a gender comparison.

The study evaluated the interactions of puberty and obesity on substrate oxidation of overweight girls (n = 38) and boys (N = 35; BMI > 85th percentile) matched for gender, age, and puberty (pre/pubertal) with normal weight girls and boys. Metabolic rates (VO(2)) were obtained during rest and at 4, 5.6 and 8 k/h. Carbohydrate oxidation rates (mg/kgFFM/min) adjusted for % predicted VO(2max), were higher for prepubertal OW children than pubertal children (p < .03). Fat oxidation rates were higher for NW prepubertal boys compared with other boys. Results indicate that OW children, regardless of gender or pubertal status, increase their carbohydrate oxidation rate to compensate for higher than normal metabolic rates. The effects of obesity on the substrate use is marginally related to puberty.

Importance of proper scaling of aerobic power when relating to cardiometabolic risk factors in children.

BACKGROUND: The relationship between cardiometabolic risk factors (CMRF) and aerobic power (VO(2max)) scaled as mL O(2) per kilogram body mass is controversial because mass includes both fat and fat-free mass, and fat mass is independently associated with the CMRF. AIM: To examine common units used to scale VO(2max) and their relationships to mean blood pressure (MBP), total cholesterol (TC), HDL cholesterol, triglycerides (TG), insulin resistance (HOMA-IR) and cumulative risk score (z-score). SUBJECTS: 1784, 8-18 year-old youths, 938 girls and 886 boys. METHODS: Fasting blood samples were obtained. VO(2max) was estimated in mL/min from cycle ergometry and scaled to body mass (kg), fat free mass (kg(FFM)), body surface area (m(2)), height (cm) and allometric (mL/kg(0.67)/min). RESULTS: Unadjusted correlations between CMRF and many of the scaled VO(2max) units were significant (p < 0.0001), especially for MBP, HOMA-IR, HDL and z-score, with lower correlations for TC and TG. After adjusting for ancestry, sex, height and body fat associations were greatly weakened (r < 0.09), except for MBP. CONCLUSIONS: On a population basis, the physical characteristics of the child, especially body fat, are more related to CMRF than any scaled units of VO(2max); thus care is needed when relating fitness and health issues.

Core temperature influences on the relationship between exercise-induced leukocytosis and cortisol or TNF-alpha.

INTRODUCTION: The extent to which exercise in the heat modifies leukocytosis and the relationship between the leukocytosis and tumor necrosis factor-alpha (TNF-alpha) or cortisol is not well understood. Thus, this study attempted to determine the combined effect of exercise and differing elevations in core temperature on exercise-induced leukocytosis and to examine associations between any leukocytosis and cortisol orTNF-alpha. METHODS: Eight male subjects completed two 40-min trials while immersed in 25 and 38.5 degrees C water. Leukocytes, TNF-alpha, and cortisol were determined at baseline, immediately post-, and 2 h post-exercise. RESULTS: Both trials resulted in significant 13-33% increases in total leukocytes, mostly driven by a 24-30% increase in neutrophils. A significant relationship was found between the change in core temperature (T(re)) during exercise and the increase in total leukocytes (r = 0.561). Similarly, the change in T(re) was related to the change in cortisol (r = 0.557) and TNF-alpha (r = 0.483). Yet the exercise-induced change in cortisol was not significantly correlated to any changes in leukocytes. There was a trend for the relationships between the exercise-induced change in TNF-alpha and the changes in total leukocytes (r = 0.491) and neutrophils (r = 0.479). DISCUSSION: These results suggest that although neither cortisol nor TNF-alpha are strong predictors of the leukocyte response during exercise or recovery, each factor may be one of many potential modifiers of the total leukocyte response.

An exploratory study of the effects of strenuous exercise on markers of coagulation activation, circulating microparticles, and inflammation in sickle cell trait.

This exploratory study evaluated the effect of intense exercise on biomarkers of inflammation and coagulation activation in subjects with and without sickle cell trait (SCT). Fifteen healthy African American men (18-35 years, 5 SCT, 10 control) completed a strenuous exercise protocol. Microparticle-associated prothrombinase and tissue factor activities, as well as soluble VCAM, total white cell and monocyte count increased transiently in all subjects following exercise. In the SCT group, exercise resulted in increased d-dimer, erythrocyte phosphatidylserine exposure, as well as increased circulating erythrocyte- and endothelial-derived microparticle numbers. These alterations could contribute to exercise-related complications in people with SCT.

The effects of menstrual cycle phase on clinical measures of concussion in healthy college-aged females.

The management of concussion and mild traumatic brain injury is an area of clinical uncertainty for many sports medicine professionals. While recent studies suggest sex differences in neurocognitive function may exist, our understanding of the effects of menstrual cycle phase and oral contraceptive pill (OCP) use in healthy females is limited. The purpose of this study was to investigate whether there were changes in neurocognitive function, postural stability and self-reported symptoms between the early and late stages of the menstrual cycle, and also to identify whether performance across menstrual cycle would differ between females using OCP and eumenorrheic females not using OCP. Healthy college-aged females completed a standard concussion test battery including computerised assessment of neurocognitive function, postural stability and symptom status. Participants completed the counterbalanced testing design during the early and late phases of their menstrual cycle. No significant main effects or interactions for any neurocognitive function or postural stability outcome measure were observed. Eumenorrheic females endorsed a higher number of symptoms and reported an increased symptom severity score compared to females using OCP. Menstrual cycle phase had no effect on the total severity or the number of symptoms endorsed. These results suggest preseason neurocognitive and postural stability baseline tests are stable across the menstrual cycle, regardless of OCP use. Therefore, decreased performance on these measures following a suspected concussion is likely not attributable to menstrual cycle phase or use of OCP.

The association between insulin resistance and cytokines in adolescents: the role of weight status and exercise.

Increased adiposity is associated with insulin resistance (IR) and an inflammatory response in adults. We tested the hypotheses that cytokines associated with adiposity are also correlated with IR in early adolescents and that these relationships are moderated by weight status, levels of vigorous physical activity (VPA), or maximal aerobic power (pVO2max). Body mass, stature, and a fasting blood sample were obtained from 120 midpubertal adolescents (60 girls and 60 boys). Habitual VPA was obtained by a survey. Predicted VO2max was determined using a cycle ergometer test. Weight status was based on body mass index (BMI) percentiles (normal weight=BMI<75th percentile, overweight=BMI>95th percentile). Glucose, insulin, adiponectin, resistin, tumor necrosis factor-alpha (TNF-alpha), and interleukin-6 were measured; and IR index was based on the Homeostatic Model Assessment. Adiponectin, resistin, and TNF-alpha were associated with IR in all adolescents (R2=0.329, P<.001; R2=0.152, P=.001; and R2=0.141, P=.002; respectively); but interleukin-6 was not (R2=0.148, P=.114). The degree of association between adiponectin and IR was stronger in overweight than in normal-weight adolescents (P<.050). When regression models included weight status, neither TNF-alpha nor resistin was significantly related to IR (P>.050). Exercise did not moderate the association between these cytokines and IR. However, higher levels of VPA and/or pVO2max were associated with higher adiponectin, lower resistin, and lower TNF-alpha in at least one of the sexes. Our results indicate that the pathophysiology of obesity is already established in early adolescents. Increased adiposity, resulting in reduced adiponectin and increased resistin and TNF-alpha, may link these cytokines with IR in adolescents.

Do surrogate markers for adiposity relate to cytokines in adolescents?

PURPOSE: To determine the associations between field-collected surrogates of adiposity and concentrations of resistin, tumor necrosis factor alpha (TNF-alpha), interleukin-6 (IL-6), and adiponectin in youth. METHODS: Cross-sectional data from 60 normal weight and 60 overweight adolescents, ages 10-14 years, were retrospectively examined. Body mass index (BMI) percentile, sum of subscapular and triceps skinfolds (SSF), and waist circumference (WC) were used to classify weight status (BMI) or adiposity (SSF and WC). Percentiles for each surrogate were used for comparison groups. Fasting TNF-alpha, IL-6, resistin, and adiponectin concentrations were measured in plasma. RESULTS: Multiple regression models, controlling for sex and ethnicity, indicated that TNF-alpha was associated with BMI percentile (R(2) = 0.107, P < 0.05) and SSF (R(2) = 0.085, P < 0.05), whereas resistin was associated with SSF (R(2) = 0.118, P < 0.05). Adiponectin was associated with all 3 adiposity markers: BMI percentile (R(2) = 0.298, P < 0.05), SSF (R(2) = 0.297, P < 0.05), and waist (R(2) = 0.278, P < 0.05). Analyses of variance indicated higher TNF-alpha and lower adiponectin concentrations in youth with a BMI higher than the 95th percentile (P = 0.014; P < 0.001) or SSF higher than the 95th percentile (P = 0.025; P < 0.001). Youth with WC higher than the 90th percentile had higher resistin (P = 0.029), higher IL-6 (P = 0.028), and lower adiponectin (P < 0.001) concentrations. CONCLUSIONS: Of the 3 surrogates examined, differences in cytokine concentrations were mostly observed in youth who had WC percentiles higher than the 90th percentiles versus WC lower than the 75th percentiles. Alternatively, from the multiple-regression models SSF, an estimate of subcutaneous adiposity was the surrogate most consistently related to all cytokines, although the degrees of associations were low. The results suggest that although some surrogates were more strongly associated to certain cytokines, WC and SSF seemed more closely associated with cytokines than a BMI percentile indicating obesity.