[Lipid and metabolic profiles in adolescents are affected more by physical fitness than physical activity (AVENA study)]

Muscular strength and markers of insulin resistance in European adolescents: the HELENA Study

The aim of the study was to examine the association of muscular strength with markers of insulin resistance in European adolescents. The study comprised a total of 1,053 adolescents (499 males; 12.5-17.5 years) from ten European cities participating in the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) Cross-Sectional Study. Muscular strength was measured by the handgrip strength and standing long jump tests. Cardiorespiratory fitness was measured by the 20-m shuttle run test. Fasting insulin and glucose were measured and the homeostasis model assessment (HOMA) and quantitative insulin sensitivity check index (QUICKI) indices were calculated. Weight, height, waist circumference and skinfold thickness were measured, and body mass index (BMI) was calculated. In males, the handgrip strength and standing long jump tests were negatively associated with fasting insulin and HOMA (all P < 0.05) after controlling for pubertal status, country and BMI or waist circumference. When skinfold thickness was included in the model, the association became non-significant. In females, the standing long jump test was negatively associated with fasting insulin and HOMA (all P < 0.001) after controlling for pubertal status, country and surrogate markers of total or central body fat (BMI, waist circumference or skinfold thickness). Findings were retained in males, but not in females after controlling for cardiorespiratory fitness. The findings of the present study suggest that preventive strategies should focus not only on decreasing fatness and increasing cardiorespiratory fitness but also on enhancing muscular strength.

Associations of physical activity with muscular fitness in adolescents

The aim of this study was to examine the associations between objectively assessed physical activity (PA) and muscular fitness (MF) in adolescents, and to determine whether only resistance training exercise is associated with the increase of MF. A sample of 211 Spanish adolescents (105 girls) wore the ActiGraph monitor for 7 days. Participants also completed a fitness evaluation including three MF tests (handgrip strength, a 60-s abdominal test and a standing broad jump), a cardiorespiratory fitness assessment and anthropometric measures. A standardized MF score was computed using the three muscular tests. Adolescent participation in resistance training was self-reported. Linear regression showed that only vigorous PA was significantly (P=0.041) and positively (β=0.133) associated with MF after adjustment by gender, age, pubertal status, BMI, and cardiorespiratory fitness. Significant differences in MF were found between youth in the lowest and upper tertiles of vigorous PA. Moreover, adolescents who were involved in resistance training had significantly higher MF scores compared with youth in low and medium tertiles of vigorous PA, but no significant differences were found when compared with non-lifters from the highest tertile of vigorous PA (P=0.356). These findings suggest that vigorous activity may be associated with indicators of MF in adolescents.

Influence of muscle fitness test performance on metabolic risk factors among adolescent girls

BACKGROUND

The purpose of this study was to examine the association between muscular fitness (MF), assessed by 2 components of Fitnessgram test battery, the Curl-Up and Push-Ups tests and the metabolic risk score among adolescent girls.

METHODS

A total of 229 girls (aged 12-15 years old) comprised the sample of this study. Anthropometric data (height, body mass, waist circumference) were collected. Body mass index (BMI) was also calculated. Muscular strength was assessed taking into account the tests that comprised the FITNESSGRAM test battery, i.e. the curl-up and the push-up. Participants were then categorized in one of 3 categories according the number of tests in which they accomplished the scores that allow them to be classified in health or above health zone. The blood pressure [BP], fasting total cholesterol [TC], low density lipoprotein-cholesterol [LDL-C], high density lipoprotein-cholesterol [HDL-C], triglycerides [TG], glucose, and a metabolic risk score (MRS) were also examined. Physical Activity Index (PAI) was obtained by questionnaire.

RESULTS

Higher compliance with health-zone criteria (good in the 2 tests), adjusted for age and maturation, were positive and significantly (p </= 0.05) associated with height (r = 0.19) and PAI (r = 0.21), while a significant but negative association was found for BMI (r = -0.12); WC (r = -0.19); TC (r = -0.16); TG (r = -0.16); LDL (r = -0.16) and MRS (r = -0.16). Logistic regression showed that who were assigned to MF fittest group were less likely (OR = 0.27; p = 0.003) to be classified overweight/obese and less likely (OR = 0.26; p = 0.03) to be classified as having MRS. This last association was also found for those whom only performed 1 test under the health zone (OR = 0.23; p = 0.02).

CONCLUSIONS

Our data showed that low strength test performance was associated with increased risk for obesity and metabolic risk in adolescent girls even after adjustment for age and maturation.

Il6 gene promoter polymorphism (-174G/C) influences the association between fat mass and cardiovascular risk factors

During the last decades, the prevalence of obesity has increased rapidly among young people. A polymorphism in the promoter region of the IL6 gene (-174G/C), has been previously reported to be involved in obesity and metabolic syndrome development. Therefore, the aim of the study was to examine whether the IL6-174G/C polymorphism influence the association of body fat with low-grade inflammatory markers and blood lipids and lipoproteins in Spanish adolescents. 504 Spanish adolescents participating in the AVENA study were genotyped for the-174G/C polymorphism of the IL6 gene. Anthropometric and body composition measurements were taken and blood samples were collected for plasma molecules determinations. No differences between genotypes were observed in anthropometric values, body composition measurements and plasma markers concentration. Physical activity level differ between genotypes with subjects carrying the C allele of the polymorphism being significantly (p<0.05) more active than GG subjects. The association between body fat mass and plasma glucose was influenced by the -174G/C polymorphism of the IL6 gene. Subjects carrying the C allele of the mutation seem to have higher values of lipoprotein (a) and C-reactive protein as their percentage of body fat mass increase. Our results suggest that this promoter polymorphism influences the association between adiposity and some plasma markers.

Validity of the Bouchard activity diary in Spanish adolescents

Objective

Valid and simple instruments to assess physical activity (PA) in specific populations are required for health-related research. The aim of the present study was to assess the validity of the Bouchard activity diary (AD) in Spanish adolescents using an activity monitor to compare total PA and moderate-to-vigorous PA (MVPA) obtained by both instruments.

Design

Sixty-one Spanish adolescents, aged 12–16 years, completed the Bouchard AD and wore the ActiGraph activity monitor for three consecutive days. Validity was assessed with the Spearman correlation coefficient (ρ), the Bland–Altman method and the κ coefficient.

Results

Thirty-seven adolescents were included in the final analysis. Correlations between the activity monitor and the AD administered over the three days (Thursday–Saturday) were moderate (ρ = 0·33–0·35, P < 0·05) or non-significant for total PA and moderate (ρ = 0·36, P < 0·05) for MVPA. Correlations between the two methods were progressively lower for each subsequent day of testing, for both total PA and MVPA. The Bland–Altman plot illustrated that the Bouchard AD overestimated MVPA (mean difference −32·05 (sd 74·56) min; 95 % limits of agreement 109·61, −173·31 min). Agreements for classification into MVPA tertiles and accordance with the international recommendations of MVPA were fair and moderate, respectively, for the 3 d means.

Conclusions

The Bouchard AD has reasonable validity to assess total PA and MVPA in Spanish adolescents. The results show lower levels of agreement on the third day but it is not clear if this is due to design features (weekday v. weekend) or to participant compliance with the survey or the activity monitoring protocol.

Cardiometabolic disease in latin america: the role of fetal programming in response to maternal malnutrition

Latin America is experiencing an epidemic of cardiovascular disease and type-2 diabetes mellitus. The rise in life-expectancy and increasingly rapid urbanization have resulted in a greater prevalence of overweight, obesity and metabolic syndrome. In Latin America, there is a high level of susceptibility to the development of insulin resistance and low-grade inflammation at relatively low levels of abdominal obesity. This susceptibility is associated with the adaptive response of the fetus to deficient fetal nutrition, which results in a loss of anatomical structures such as nephrons, cardiomyocytes and pancreatic beta cells. These adaptations may prove detrimental if food becomes abundant again after birth. In Latin America, the high prevalence of maternal and fetal malnutrition could mean that the resulting fetal adaptations may contribute to an increased risk of cardiometabolic disease. The socioeconomic differences that exist between developed and underdeveloped countries may be reflected in different biological adaptations, which could invalidate the diagnostic criteria and preventive and therapeutic approaches that have been recommended on the basis of research carried out in populations with different characteristics. Clinical studies are needed to evaluate the effectiveness of interventions recommended for preventing and aiding recovery from cardiometabolic disease in Latin America.

[Update on pediatric cardiology and congenital heart disease]

The fields of pediatric cardiology and congenital heart disease have experienced considerable progress in the last few years, with advances in new diagnostic and therapeutic techniques that can be applied at all stages of life from the fetus to the adult. This article reviews scientific publications in a number of areas that appeared between August 2007 and September 2008. In developed countries, congenital heart disease is becoming increasingly prevalent in nonpediatric patients, including pregnant women. Actions aimed at preventing coronary heart disease must be started early in infancy and should involve the promotion of a healthy diet and lifestyle. Recent developments in echocardiography include the introduction of three-dimensional echocardiography and of new techniques such as two-dimensional speckle tracking imaging, which can be used for both anatomical and functional investigations in patients with complex heart disease, including a univentricular heart. Progress has also occurred in fetal cardiology, with new data on prognosis and prognostic factors and developments in intrauterine interventions, though indications for these interventions have still to be established. Heart transplantation has become a routine procedure, supplemented in some cases by circulatory support devices. In catheter interventions, new devices have become available for the closure of atrial or ventricular septal defects and patent ductus arteriosus as well as for percutaneous pulmonary valve implantation. Surgery is also advancing, in some cases with hybrid techniques, particularly for the treatment of hypoplastic left heart syndrome. The article ends with a review of publications on cardiomyopathy, myocarditis and the treatment of bacterial endocarditis.

Physical activity, cardiorespiratory fitness, and the metabolic syndrome in youth

The metabolic syndrome is defined as the coexistence of multiple cardiovascular and diabetes risk factors, the prevalence of which has increased dramatically in adult populations in the last decades. More recently, the same cluster of metabolic risk factors has also been recognized in children and adolescents. Epidemiological evidence suggests that high levels of cardiorespiratory fitness (CRF) and physical activity are associated with a favorable metabolic risk profile in adults. However, in youth the role of these factors is less clear. Therefore, the purpose of this mini-review is to examine the recent evidence between objectively measured habitual physical activity and CRF with clustered metabolic risk in youth. In general, it appears that both physical activity and CRF are separately and independently associated with metabolic risk factors in youth, possibly through different causal pathways. Further research is necessary to quantify how much physical activity is needed to prevent the metabolic syndrome and the diseases with which it is associated. Public health approaches that encourage increased physical activity and reduce sedentary behaviors may prove useful in reducing the population burden associated with metabolic risk.

Physical fitness in childhood and adolescence: a powerful marker of health

This review aims to summarize the latest developments with regard to physical fitness and several health outcomes in young people. The literature reviewed suggests that (1) cardiorespiratory fitness levels are associated with total and abdominal adiposity; (2) both cardiorespiratory and muscular fitness are shown to be associated with established and emerging cardiovascular disease risk factors; (3) improvements in muscular fitness and speed/agility, rather than cardiorespiratory fitness, seem to have a positive effect on skeletal health; (4) both cardiorespiratory and muscular fitness enhancements are recommended in pediatric cancer patients/survivors in order to attenuate fatigue and improve their quality of life; and (5) improvements in cardiorespiratory fitness have positive effects on depression, anxiety, mood status and self-esteem, and seem also to be associated with a higher academic performance. In conclusion, health promotion policies and physical activity programs should be designed to improve cardiorespiratory fitness, but also two other physical fitness components such us muscular fitness and speed/agility. Schools may play an important role by identifying children with low physical fitness and by promoting positive health behaviors such as encouraging children to be active, with special emphasis on the intensity of the activity.