Independent association of clustered metabolic risk factors with cardiorespiratory fitness in youth aged 11-17 years

Clustering of cardiometabolic risk factors and the continuous cardiometabolic risk score in children from Southern Brazil: a cross-sectional study

Purpose

The present study aimed to verify the clustering of cardiometabolic risk factors for cardiovascular diseases (CVD) and its relationship with the continuous cardiometabolic risk score (cMetS).

Methods

Cross-sectional study with 631 children aged 6 to 9 years. Cardiorespiratory fitness, glucose, systolic blood pressure, total cholesterol/high-density lipoprotein cholesterol ratio, triglycerides, and waist circumference were assessed. The number of children in whom the risk factors were not independently distributed was analyzed. Z-scores were computed for each risk factor to calculate the cMetS.

Results

There was a high proportion of children with clustering of risk factors for CVD. The clustering of risk factors was apparent in 11.3% of the children for four or more risk factors, and 21.9% had three or more risk factors. The cMetS showed a linear relationship with the increase in the number of risk factors. A cMetS value higher than 0.91 indicated clustering of cardiometabolic risk factors amongst children.

Conclusion

The use of clustering of cardiometabolic risk factors identified a high proportion of children with the presence of relevant cardiometabolic alterations. A cMetS value higher than 0.91 (relative to an international standard) indicated higher clustering of cardiometabolic risk factors amongst children.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-021-00845-9.

Assessment of Secular Trends and Health Risk in Pediatric Cardiorespiratory Fitness From the Republic of Slovenia

Objectives

Determine the temporal trends in cardiorespiratory fitness (CRF) and health risk of Slovenian schoolchildren across a 20-year span, assessed via 20-m shuttle run (20mSRT), including defining centile ranges and possible health risk(s) for each generation.

Methods

Nationally representative data from 9,426 healthy schoolchildren (6–14 years old) were used to determine changes in CRF across three generations, in 1993 (n = 3,174), 2003 (n = 3,457) and 2013 (n = 2,795) from a multistage, stratified, decennial study.

Results

20mSRT performance declined ∼2.8% from 1993 to 2003, independent of age or sex of the child. This trend was reversed in 2013, increasing by ∼8.2% across all age groups, for both girls and boys, for a net increase of 5.4%. The magnitude of improvement was similar for both sexes. Moreover, girls in the 2013 generation (for ages 10–13 year) completed more stages than their 2003 male counterparts. Across all generations, children achieved CRF values corresponding to low cardiovascular risk for future health outcomes. Centile values ranged from “low” to “very high” depending on age, sex, and generation of the sample.

Conclusion

Negative trends in CRF from Slovenian schoolchildren were reversed by 2013, indicating that Slovenia should continue implementing progressive national physical fitness strategies introduced between sampling periods (i.e., 2003–2013). Additionally, due to the universal nature of Slovenian schoolchildren achieving “healthy cut-off values” for 20mSRT (generation-inclusive), it is suggested that more specific cut-off criteria are developed, especially for younger children, and girls, so that future CRF results can be more accurately applied for both clinical and pedagogical users.

Novel Insights into the Pathogenesis and Management of the Metabolic Syndrome

The metabolic syndrome, by definition, is not a disease but is a clustering of individual metabolic risk factors including abdominal obesity, hyperglycemia, hypertriglyceridemia, hypertension, and low high-density lipoprotein cholesterol levels. These risk factors could dramatically increase the prevalence of type 2 diabetes and cardiovascular disease. The reported prevalence of the metabolic syndrome varies, greatly depending on the definition used, gender, age, socioeconomic status, and the ethnic background of study cohorts. Clinical and epidemiological studies have clearly demonstrated that the metabolic syndrome starts with central obesity. Because the prevalence of obesity has doubly increased worldwide over the past 30 years, the prevalence of the metabolic syndrome has markedly boosted in parallel. Therefore, obesity has been recognized as the leading cause for the metabolic syndrome since it is strongly associated with all metabolic risk factors. High prevalence of the metabolic syndrome is not unique to the USA and Europe and it is also increasing in most Asian countries. Insulin resistance has elucidated most, if not all, of the pathophysiology of the metabolic syndrome because it contributes to hyperglycemia. Furthermore, a major contributor to the development of insulin resistance is an overabundance of circulating fatty acids. Plasma fatty acids are derived mainly from the triglycerides stored in adipose tissues, which are released through the action of the cyclic AMP-dependent enzyme, hormone sensitive lipase. This review summarizes the latest concepts in the definition, pathogenesis, pathophysiology, and diagnosis of the metabolic syndrome, as well as its preventive measures and therapeutic strategies in children and adolescents.

Physical activity maintenance and metabolic risk in adolescents

Aim

Examine the association between child and adolescent physical activity maintenance categories and metabolic profile in adolescence.

Methods

This cross-sectional study was conducted with 1152 adolescents (57.4% female) aged 10-16 years from Londrina, Brazil. Physical activity was self-reported in childhood (7-10 years old, retrospective data) and adolescence through questionnaires. Cardiorespiratory fitness (20 m shuttle-run test), body fat (skinfolds), waist circumference, blood pressure (automatic instrument) and blood variables (fasting glucose, HDL-cholesterol and triglycerides) were measured at adolescence.

Results

Frequency of physical activity in childhood and adolescence was 50.3 and 17.2%, respectively, and only 25.7% of boys and 10.9% of girls were active at both ages. Adolescents who were physically active in childhood alone were less likely [OR = 0.71 (95% CI: 0.52-0.97)] to present low cardiorespiratory fitness in adolescence compared to those who were non-active in childhood. Regardless of controlled, actives in childhood and adolescence were less likely to present low cardiorespiratory fitness [OR = 0.50 (95% CI: 0.34-0.73)], high blood pressure [OR = 0.52 (95% CI: 0.32-0.85)] and high metabolic risk score [OR = 0.44 (95% CI: 0.22-0.90)] compared to the non-actives at both ages.

Conclusions

Actives through childhood to adolescence are less likely to present low cardiorespiratory fitness, high blood pressure and high metabolic risk.

Youth cardiorespiratory fitness: evidence, myths and misconceptions

Rigorously determined peak oxygen uptake is internationally recognized as the criterion measure of youth cardiorespiratory fitness. The assessment and interpretation of children’s and adolescents’ peak oxygen uptake and the relationship of the measure with other health-related variables are well documented. There has been a recent resurgence of interest in the prediction of peak oxygen uptake from field performance tests in young people. However, coupled with ratio-scaling of data and the raising of clinical red flags, these practices risk clouding our understanding of youth cardiorespiratory fitness and its relationship with current and future health. We believe these methods have the potential to mislead clinical practice and misguide recommendations for the promotion of youth cardiovascular health. We discuss relevant scientific evidence and interpretations that have emerged from predicting youth cardiorespiratory fitness from performance test scores. We argue that children deserve to have health care founded on evidence-based science and not on myths and misconceptions.

TRACKING OF CARDIORESPIRATORY FITNESS FROM CHILDHOOD TO EARLY ADOLESCENCE: MODERATION EFFECT OF SOMATIC MATURATION

Objective:

To evaluate cardiorespiratory fitness’ tracking from childhood to adolescence, as well as to test the moderation role of somatic maturation.

Methods:

Our sample was composed by 375 children (197 boys), with a baseline age between 7 and 10 years old. The children were followed-up over three years. Body mass and stature were measured as anthropometric indicators and were used to estimate maturity status through Moore’s method. Cardiorespiratory fitness was evaluated through 9-minute running test. Body adiposity was estimated through the subcutaneous skinfold method, with measures of triceps and subscapular skinfolds and used as a covariate. Sample was categorized into tertiles. Thereafter, the Kappa (k) coefficient and Lin’s concordance correlation coefficient (LCCC) tests were adopted to verify stability. Dummy variable in regression was used to test moderation effects. All analyses were conducted in Stata 14.0, adopting p<0.05.

Results:

Cardiorespiratory fitness presented a moderate to low tracking from childhood to adolescence (k=0.294; LCCC=0.458). Moreover, maturity status significantly moderated the association between cardiorespiratory fitness at childhood and adolescence (regardless of cohort and body adiposity) among boys (β=0.644; p=0.003) and role sample (β=0.184; p=0.020), but not girls (-0.217; p=0.413).

Conclusions:

Tracking of cardiorespiratory fitness from childhood to adolescence is moderate to low in both sexes. Moreover, maturity status moderated the relationship between cardiorespiratory fitness at baseline and in adolescence. A lower age at peak height velocity was associated to a greater cardiorespiratory fitness.

Allometric scaling of aerobic fitness outputs in school-aged pubertal girls

Background

This study aimed to determine the allometric exponents for concurrent size descriptors (stature, body mass and fat-free mass) and also to examine the contribution of chronological age and pubertal status combined with above mentioned size descriptors to explain inter-individual variability in the peak of oxygen uptake (VO_2peak) among girls during circumpubertal years.

Methods

The final sample included 51 girls (10.7–13.5 years). VO_2peak was derived from an incremental progressive maximal protocol using a motorized treadmill. Anthropometry included body mass, stature and skinfolds. Measurements were performed by a single trained observer. Sexual maturation was assessed as self-reported stage of pubic hair (PH) development. Static allometric models were explored as an alternative to physiological output per unit of size descriptors. Allometry also considered chronological age and sexual maturation as dummy variable (PH2 vs. PH3 and PH3 vs. PH4).

Results

Scaling coefficients for stature, body mass and fat-free mass were 1.463 (95%CI: 0.476 to 2.449), 0.516 (95%CI: 0.367 to 0.666) and 0.723 (95%CI: 0.494 to 0.951), respectively. The inclusion of sexual maturation increased explained variance for VO_2peak (55% for PH2 vs. PH3 and 47% for PH3 vs. PH4). Body mass was identified as the most prominent body size descriptor in the PH2 vs. PH3 while fat-free mass was the most relevant predictor combined with PH3 vs. PH4.

Conclusions

Body mass and fat-free mass seemed to establish a non-linear relationship with VO_2peak. Across puberty, inter-individual variability in VO_2peak is explained by sexual maturation combined with whole body during early puberty and by sexual maturation and fat-free mass during late puberty. Additional studies need to confirm ontogenetic allometric models during years of maximal growth.

Physical Fitness and Metabolic Syndrome in Brazilian Adolescents: Validity of Diagnostic Health Criteria

We tested health criteria cutoff points from physical fitness variables proposed by the Fitnessgram program for detecting metabolic syndrome ( MetS) in a representative sample of 1,035 Brazilian adolescents (565 girls and 470 boys) aged 12-20 years. We studied five fitness tests: (a) back-saver sit and reach, (b) trunk lift, (c) curl-up, (d) push-up, and (e) progressive aerobic cardiovascular endurance run ( PACER), and we defined MetS through the criteria of the International Diabetes Federation. We described the predictive performance of each fitness test in terms of sensitivity, specificity, and area under the curve ( AUC) estimates of the receiver operating characteristic method. The AUCs for four tests ( back-saver sit and reach, trunk lift, curl-up, and push-up) revealed low accuracy for identifying MetS in both sexes (0.50 ≥ AUC ≤ 0.60), but AUCs for the PACER test demonstrated good accuracy values between 0.72 (0.68-0.76) and 0.83 (0.78-0.89). Thus, cutoff points proposed in the Fitnessgram program for the PACER test offer an effective means of screening adolescents at higher cardiometabolic risk, which, for the age-group used in this study, should be from 40.3-44.3 ml/kg/min for boys and 38.6-40.1 ml/kg/min for girls.

Social, behavioral and biological correlates of cardiorespiratory fitness according to sex, nutritional status and maturity status among adolescents. A cross-sectional study

BACKGROUND

Our aim was to analyze multilevel correlates of cardiorespiratory fitness (CRF) according to sex, nutritional status and maturity status among adolescents.

DESIGN AND SETTING

Cross-sectional study conducted in public schools.

METHODS

This was a cross-sectional study on 1,209 adolescents aged between 10 and 17 years. CRF was estimated from the 20-meter shuttle run test. Anthropometric data on body mass index and waist circumference were obtained. Somatic maturation was assessed from the peak height velocity. Questionnaires were used to evaluate socioeconomic variables (family income, parents' education level and number of siblings) and behavioral variables (physical activity, screen time and alcohol and tobacco consumption) among the parents and adolescents.

RESULTS

Boys, adolescents with normal weight and on-time maturers presented greater CRF (P < 0.05). Concerning socioeconomic correlates, girls (tobacco smoking, alcohol consumption, physical activity and screen time), adolescents with normal weight (alcohol consumption, physical activity and screen time), and on-time maturers (alcohol consumption, physical activity during childhood and habitual physical activity) demonstrated higher numbers of behavioral correlates with CRF. Normal-weight adolescents presented a higher number of biological correlates (chronological age, age at peak height velocity and waist circumference).

CONCLUSIONS

Different correlates were observed according to sex, nutritional status and somatic maturation status. However, habitual physical activity, waist circumference and chronological age seemed to be the strongest factors associated with cardiorespiratory fitness among adolescents.

Independent and Combined Effects of Weight Status and Maturation on Aerobic Fitness in Adolescent School-Aged Males

Batista, MB, Valente-dos-Santos, J, Duarte, JP, Sousa-e-Silva, P, Coelho-e-Silva, MJ, Werneck, AO, Ohara, D, Cyrino, ES, and Ronque, ERV. Independent and combined effects of weight status and maturation on aerobic fitness in adolescent school-aged males. J Strength Cond Res 34(9): 2663-2671, 2020-This study aimed to examine the independent and combined effects of pubertal and weight status on concurrent measurements of peak oxygen (V[Combining Dot Above]O2peak) in school-aged adolescent males. The final sample included 49 boys (12.3 ± 0.8 years). V[Combining Dot Above]O2peak was derived from an incremental progressive maximal protocol using a motorized treadmill. In addition, maximal oxygen uptake was estimated from a 20-m shuttle run test. Static allometric models were obtained as an alternative to performance output per unit of size descriptors. Weight status had a significant effect on V[Combining Dot Above]O2peak using simple ratio standards per unit of body mass (BM) with adolescents classified as overweight and obese (OWOB) attaining lower values of V[Combining Dot Above]O2peak. A similar trend was noted for the allometric models adopting body mass (ml·kgBM·min), stature (L·m·min), and fat-free mass (FFM; ml·kgFFM·min). Findings also suggest the influence and interaction of pubertal and weight status on absolute values of V[Combining Dot Above]O2peak. Considering the data obtained, linear equations to estimate V[Combining Dot Above]O2peak from the 20-m shuttle run test should not be applied to boys who are OWOB because it will produce inaccurate assessments of cardiorespiratory fitness and penalize those who are heavier. Equations for V[Combining Dot Above]O2peak prediction need to be specific for pubertal status and preferably consider FFM as a body size descriptor.

Physical Activity and Sedentary Time Associations with Metabolic Health Across Weight Statuses in Children and Adolescents

OBJECTIVE

The aim of this study was to examine the prevalence of metabolic health across weight statuses and the associations of physical activity and sedentary time within and across metabolic health-weight status groups.

METHODS

Six studies (n = 4,581) from the International Children's Accelerometry Database were used. Sedentary time, light physical activity, and moderate to vigorous physical activity (MVPA) were accelerometer derived. Individuals were classified with normal weight (NW), overweight, or obesity. Strict and lenient composite definitions of metabolic health were created. Binomial and multinomial logistic regressions controlling for age, sex, study, and accelerometer wear time were conducted.

RESULTS

The metabolically unhealthy (MU) prevalence was 26.4% and 45.6% based on two definitions. Across definitions, more sedentary time was associated with higher odds of MU classification compared with metabolically healthy (MH) classification for the NW group. More MVPA was associated with lower odds of MU classification than MH classification for NW and overweight groups. For multinomial logistic regressions, more MVPA was associated with lower odds of MH-obesity classification, as well as MU-NW, -overweight, and -obesity classifications, compared with the MH-NW group. Furthermore, more sedentary time was associated with higher odds of MU-NW classification compared with the MH-NW group.

CONCLUSIONS

More MVPA was beneficial for metabolic health and weight status, whereas lower sedentary time was beneficial for metabolic health alone, although associations were weak.

Hyperuricemia is associated with low cardiorespiratory fitness levels and excess weight in schoolchildren

OBJECTIVE

To evaluate the possible association between hyperuricemia and cardiorespiratory fitness levels/nutritional profile, grouped into a single variable, in schoolchildren.

METHOD

Cross-sectional study of 2335 students from Elementary schools, aged 7-17 years of both genders, stratified by conglomerates of a municipality in Southern Brazil. Body mass index (BMI) was calculated and cardiorespiratory fitness (CRF) was assessed by the 6-minute run/walk test. The BMI and CRF were grouped into a single variable, considering: (1) low and normal weight/fit; (2) low and normal weight/unfit; (3) overweight-obesity/fit; (4) overweight-obesity/unfit. The Poisson regression (prevalence ratio, PR) was used for the association between hyperuricemia and BMI/CRF ratio with 95% confidence intervals and differences were considered significant when p<0.05.

RESULTS

There is an association, although subtle, between the presence of hyperuricemia with low levels of CRF and the presence of excess weight, when grouped into a single variable. Boys and girls with this condition have higher prevalence of hyperuricemia (PR: 1.07; p=0.007 for boys; PR: 1.10; p<0.001 for girls).

CONCLUSION

Together, excess weight and low levels of cardiorespiratory fitness are associated with the presence of hyperuricemia in schoolchildren.

Normative reference values for the 20 m shuttle-run test in a population-based sample of school-aged youth in Bogota, Colombia: the FUPRECOL study

OBJECTIVES

Our aim was to determine the normative reference values of cardiorespiratory fitness (CRF) and to establish the proportion of subjects with low CRF suggestive of future cardio-metabolic risk.

METHODS

A total of 7244 children and adolescents attending public schools in Bogota, Colombia (55.7% girls; age range of 9-17.9 years) participated in this study. We expressed CRF performance as the nearest stage (minute) completed and the estimated peak oxygen consumption (V˙O2peak ). Smoothed percentile curves were calculated. In addition, we present the prevalence of low CRF after applying a correction factor to account for the impact of Bogota's altitude (2625 m over sea level) on CRF assessment, and we calculated the number of participants who fell below health-related FITNESSGRAM cut-points for low CRF.

RESULTS

Shuttles and V˙O2peak were higher in boys than in girls in all age groups. In boys, there were higher levels of performance with increasing age, with most gains between the ages of 13 and 17. The proportion of subjects with a low CRF, suggestive of future cardio-metabolic risk (health risk FITNESSGRAM category) was 31.5% (28.2% for boys and 34.1% for girls; X2 P = .001). After applying a 1.11 altitude correction factor, the overall prevalence of low CRF was 11.5% (9.6% for boys and 13.1% for girls; X2 P = .001).

CONCLUSIONS

Our results provide sex- and age-specific normative reference standards for the 20 m shuttle-run test and estimated V˙O2peak values in a large, population-based sample of schoolchildren from a large Latin-American city at high altitude.

Tracking cardiorespiratory fitness and physical activity in children with and without motor coordination problems

OBJECTIVES

Previous research has shown children with Developmental Coordination Disorder (DCD) have lower cardiorespiratory fitness (CRF) than typically developing (TD) children. This has been hypothesized to be due to an activity deficit, whereby poor motor functioning discourages children from participating in physical activities, but this hypothesis has not been directly tested. In this study, we use longitudinal data to measure the extent to which physical activity explains differences in CRF between children with and without motor coordination deficits.

DESIGN

Longitudinal observational study.

METHODS

The study sample is an open cohort of children, numbering 2278 at baseline (age 9-10), that was followed for up to 5 years (to age 13-14). Motor skills were assessed once over the study period. Children scoring at or below the 5th percentile (n=103) on the Bruininks-Oseretsky Test of Motor Proficiency-Short Form were considered to have possible DCD (pDCD). CRF (estimated peak VO₂) was estimated from performance on the Léger 20m shuttle run test, and physical activity was measured with the Participation Questionnaire. Both fitness and physical activity were measured up to 7 times over the study period.

RESULTS

Children with pDCD had significantly lower CRF than their TD peers at each time point. CRF declined for both groups, but this decline was steeper for children with pDCD. Physical activity explained only a small part of the difference in CRF.

CONCLUSIONS

The activity deficit did not contribute to the persistent and gradually widening gap in CRF between children with and without possible DCD. Possible reasons for this and future directions are discussed.

Cardiorespiratory fitness effect may be under-estimated in 'fat but fit' hypothesis studies

BACKGROUND

Both cardiorespiratory fitness and body fat have been independently related to metabolic syndrome in adolescents; however, the strength of these relationships seems to be dependent on the outcome composition.

AIM

To analyse the relationship between cardiorespiratory fitness and body fat combined with different indicators of metabolic risk in adolescents.

SUBJECTS AND METHODS

The sample was composed of 957 adolescents (58.7% girls). Cardiorespiratory fitness was obtained using the 20-metre shuttle run test and skinfold thickness was collected for body fat estimation. Metabolic risk score was calculated from waist circumference, systolic and diastolic blood pressure, glucose, HDL cholesterol and triglycerides measurements and an alternative outcome without the central obesity indicator was adopted. Chronological age and somatic maturity were used as covariates.

RESULTS

Higher metabolic risk was observed in the highest fat/lowest fit adolescents (p < .05), regardless of sex and outcome. In the regression models, for full metabolic risk score, body fat presented higher coefficients compared to cardiorespiratory fitness in both sexes (boys: 0.501 vs -0.097; girls: 0.485 vs -0.087); however, in the metabolic risk without waist circumference, the coefficients became closer (boys: 0.290 vs -0.146; girls: 0.265 vs -0.120), with a concomitant decrease in body fat and increase in cardiorespiratory fitness coefficients.

CONCLUSION

These findings suggest that body fat is strongly related to cardiovascular risk, but, when the outcome is calculated without the central obesity indicator, cardiorespiratory fitness becomes more related to metabolic risk.

Cardiorespiratory Fitness, Adiposity, and Cardiometabolic Risk Factors in Schoolchildren: The FUPRECOL Study

The aim of this study was to investigate the association between cardiorespiratory fitness (CRF) and cardiovascular risk factors (CVRF) in schoolchildren. A secondary aim was to evaluate the degree of association between overall and abdominal adiposity and CRF in a total of 1,875 children and adolescents attending public schools. We expressed CRF performance as the nearest stage (minute) completed and the estimated peak oxygen consumption. A CVRF ( Z score) was calculated and participants were divided into tertiles according to low and high levels of overall (sum of the skinfold thicknesses) and abdominal adiposity. Schoolchildren with a high-level of overall adiposity demonstrated significant differences in seven of the 10 variables analyzed (i.e., systolic and diastolic blood pressure, triglycerides, triglycerides/high density lipoproteins [HDL-c] ratio, total cholesterol, glucose, C-reactive protein [usCRP], HDL-c, low density lipoproteins [LDL-c], and cardiovascular risk score). Schoolchildren with high levels of both overall and abdominal adiposity and low CRF had the least favorable CVRF score.

Physical activity and its correlates in children and adolescents post-liver transplant

The health benefits of PA are well established for healthy and chronically ill children. This study objectively measures physical fitness and PA levels in children PLT and explores potential correlates and perceived barriers impacting their PA. A total of 23 children (16 females, mean 14.01 ± 2.49 yrs) >1 yr PLT were assessed for peak oxygen consumption (VO2 peak), muscle strength, endurance, and flexibility. MVPA and steps/day were determined with accelerometry. Additionally, SE, perceived fatigue, and barriers and benefits of PA were examined. VO2 peak (mean 33. 2 ± 7.61 mL/kg/min; 77.0 ± 15.6% predicted) and PA (average 6841 ± 2299 steps/day) were below healthy norms. MVPA (31.6 ± 16.1 min/day) was lower than national guidelines. Six participants (30%) attained criterion standards for abdominal strength and one participant (5%) for push-ups. Fatigue and SE were lower than reported levels in healthy children. A commonly perceived barrier to PA was "I am tired." A positive correlation was shown between SE and MVPA (r = 0.57, p = 0.007), SE and fatigue (r = 0.54, p = 0.01), and PELD score and fatigue (r = 0.66, p = 0.007). Children PLT demonstrate below normal levels of PA and aerobic capacity. SE is a modifiable correlate of their PA. Further investigation of the impact of PA correlates can guide the development of future innovative PA intervention strategies in children PLT.

Cardiorespiratory fitness is related to metabolic risk independent of physical activity in boys but not girls from Southern Brazil

OBJECTIVE

Our aim was to determine the relationship between cardiorespiratory fitness (CRF) and metabolic risk in adolescents from Southern Brazil.

METHODS

We performed a school-based cross-sectional study in 1,037 adolescents (436 boys) aged 10-16 years from Londrina, PR, Brazil. CRF was determined by 20-m shuttle run test. A continuous metabolic risk score was obtained from the mean of fasting glucose, triglycerides, high density lipoprotein, blood pressure, and waist circumference z-scores. Age, physical activity (Baecke questionnaire), body mass index (BMI; weight/stature(2) ), and somatic maturity (Mirwald method) were included as covariates in multiple linear regression analyses.

RESULTS

CRF was related to metabolic risk in boys (β = -0.02, P < 0.01) and girls (β = -0.01, P = 0.02) after adjusting for chronological age, BMI, and somatic maturity. However, when adjusted for physical activity, CRF failed to explain metabolic risk in girls (β = -0.01, P = 0.24).

CONCLUSION

We conclude that CRF is independently and inversely related to metabolic risk in boys, but physical activity either mediates or confounds the association between CRF and metabolic risk in girls. Am. J. Hum. Biol. 28:534-538, 2016. © 2016 Wiley Periodicals, Inc.

Metabolic risk and television time in adolescent females

OBJECTIVES

A sedentary lifestyle is increasingly implicated in a negative metabolic health profile among youth. The present study examined relationships between clustered metabolic risk factors and TV viewing in female adolescents.

METHODS

The sample comprised 262 girls 14-17 years. Height, weight, fasting glucose, insulin, HDL cholesterol, triglycerides, and blood pressure were measured. Body mass index (BMI) was calculated. TV viewing time and moderate-to-vigorous physical activity (MVPA) were estimated from a 3-day diary. Outcome variables were normalized and expressed as Z scores which were summed into a metabolic risk score. Multiple linear regression analysis was used.

RESULTS

TV viewing was independently associated with increased prevalence of clustered metabolic risk in girls after adjustment for several confounders (i.e., chronological age, BMI, MVPA, and parental education). The final model also indicated that lower levels of MVPA, higher BMI, and lower mother education were associated with higher metabolic risk.

CONCLUSIONS

Increased TV viewing had an adverse effect on metabolic health of adolescent girls. The findings highlight the potential importance of preventive actions to ameliorate metabolic risk in youth which target both sedentary and physically active behaviors.