Low Muscular Strength, Weight Status, and Metabolic Syndrome in Adolescents: National Health and Nutrition Examination Survey 2011-2014

Self-perceived physical fitness and occurrences of individual levels of autistic traits in adolescents: a cluster association study

BACKGROUND

The association between physical fitness and autistic traits in adolescents remains under explored, especially in adolescents. Understanding this relationship can provide strategies to improve the quality of life of these people.

OBJECTIVE

To identify the association between cluster characteristics derived from levels of self-perceived physical fitness and the occurrences of individual levels of autistic traits in Brazilian adolescents.

METHOD

This descriptive study employed an analytical, quantitative approach involving 515 adolescents aged 11 to 18 (245 boys and 270 girls). Autistic traits were assessed using the Autism Quotient (AQ50), while physical fitness was measured with the Self-Reported Physical Fitness Questionnaire (QAPA). Cluster analysis using descriptive statistics with bootstrapping and generalized estimating equations was performed.

RESULTS

Boys reported higher physical fitness levels than girls, with significant differences in General Power Strength (QAPA 4) and Physical Fitness in Sports (QAPA 7). Girls scored slightly higher on social skills. AQ50 scores indicated that girls had higher aggregated difficulties in imagination, attention, communication, and social skills compared to boys. Higher self-perceived physical fitness was associated with lower levels of autistic traits in both genders. Girls with higher QAPA scores showed significant decreases in autistic traits related to social skills and overall AQ50 scores. Boys with higher physical fitness demonstrated reduced autistic traits in the domains of imagination and communication. Age-adjusted analyses confirmed these findings.

CONCLUSION

There is a significant association between self-perceived physical fitness and autistic traits in adolescents. Higher physical fitness levels are linked to fewer autistic traits, highlighting the importance of promoting physical fitness to mitigate challenges associated with autistic traits and improve adolescents' well-being.

Insufficient Muscle Development Level Associated with Serum Zinc, Manganese and Cobalt Levels in Children Aged 6 to 9 Years in Shenzhen, China

Some trace elements have been found to be associated with muscle mass and muscle function; however, evidence in children is limited, and it remains unclear which trace elements are more relevant. We aimed to explore the association of levels of individual and combined essential trace elements and muscle development level (MDL) in young children. Muscle mass was measured by body composition analysis, and trace elements were determined by using inductively coupled plasma mass spectrometry (ICP-MS). Logistic regression, restricted cubic spline (RCS) and weighted quantile sum regression (WQS) were used to assess the individual and joint associations between trace element levels and MDL. We enrolled 2851 children: 1595 boys (55.9%) and mean age 7.1 years (range 6.8-7.3). The proportion of insufficient muscle mass in the whole body, limbs, upper and lower limbs was 1.9%, 6.5%, 44.9% and 4.6%, respectively. The odds of insufficient MDL decreased with the fourth versus first quartile of zinc (OR = 0.67, 95% CI: 0.51-0.89), manganese (OR = 0.80, 95% CI: 0.65-1.00), and cobalt (OR = 0.89, 95% CI: 0.81-0.99) and was increased with the fourth quartile of nickel (OR = 2.23, 95% CI: 1.72-2.89) and selenium (OR = 1.51, 95% CI: 1.14-1.98). The RCS yielded similar results, except for the discrepancy in high cobalt levels. The odds of insufficient MDL decreased with the combination of nine trace elements (OR = 0.84, 95% CI: 0.73-0.97), primarily zinc (weight = 0.297), manganese (weight = 0.198) and cobalt (weight = 0.173). Insufficient MDL in young children was mainly in upper limbs. Low levels of zinc, manganese, and cobalt, individually or combined, were significantly associated with risk of insufficient MDL. Further foods rich in zinc, manganese, and cobalt should be suggested to supplement in diet, and increase exercise of upper limbs to improve insufficient MDL in the young children should be needed.

Association of Initial Muscle Fitness with Weight Loss and Metabolically Healthy Status in Children and Adolescents with Obesity: A Retrospective Study

This retrospective study aimed to investigate the association of initial muscular fitness (MF) with weight loss and metabolic health status in 282 children and adolescents with obesity during 3 to 4 weeks of diet- and exercise-based interventions. Metabolically healthy obesity (MHO) definitions established in 2023 and MF standards based on the 2021 Chinese children's grip strength grading were applied. The proportion of metabolically unhealthy obesity (MUO) was higher in the high MF group than in their low MF counterparts at baseline. After the intervention, neither group transitioned from MUO to MHO due to the high frequency of low HDL-C. High MF females showed a higher percentage of high systolic blood pressure (SBP) than low MF females before and after intervention. High MF males exhibited greater improvements in waist circumference, hip circumference, waist-hip ratio, triglycerides, total cholesterol, and LDL-C than low MF males. The benefits of weight loss and blood lipids obtained by males are more evident than those obtained by females under the same MF level. Thus, attention should be paid to females during weight loss regardless of MF levels. Precision therapy should prioritize the management of blood pressure and avoid excessive reduction in HDL-C levels to sustain metabolic health.

The combined effect of cardiorespiratory and muscular fitness on the incidence of metabolic syndrome before midlife

BACKGROUND

Cardiorespiratory fitness (CRF) could reduce the risk of metabolic syndrome (MetS) while the association between muscular endurance capacity (MEC) and incident MetS has rarely been investigated in young adults.

METHODS

A total of 2890 military men and women, aged 18-39 years, free of baseline MetS in Taiwan, were followed for incident MetS from baseline (2014) until the end of 2020. All subjects received annual health examinations for assessment of MetS. Physical fitness was assessed by CRF (estimated maximal oxygen uptake, VO2 max [mL/kg/min], in a 3000-m run) and MEC (numbers of 2-min push-ups). MetS was defined according to the International Diabetes Federation (IDF) criteria. Multiple Cox regression analysis was conducted with adjustments for baseline age, sex, substance use status and physical activity to determine the associations of CRF and MEC with incidences of new-onset MetS and related features, for example, central obesity, hypertension, dyslipidaemia and prediabetes or diabetes. To examine the combined effects of CRF and MEC status on incidence of MetS, high and low levels of CRF and MEC were separately defined by over and under the sex-specific median in each exercise test.

RESULTS

During a median follow-up of 5.8 years, there were 673 (23.3%) new-onset MetS. Higher CRF was associated with a lower incidence of MetS (hazard ratio [HR] and 95% confidence interval: 0.905 [0.877-0.933]), and its components separately, except hypertension. No association was observed between MEC and incident MetS, and its components separately, except hypertension. When evaluating the combined effects of MEC and CRF status on the incidence of MetS, it was observed that compared with the low CRF/low MEC, the high CRF/high MEC (HR: 0.553 [0.439-0.697]) and the high CRF/low MEC (HR: 0.730 [0.580-0.918]) had a lower incidence of new-onset MetS (P value for the intergroup difference = 0.04). There was no significant result for the low CRF/high MEC.

CONCLUSIONS

This study highlights that although the protective effects of MEC to reduce the incidence of MetS and most of its related features were mainly driven by CRF in young adults, there was an addictive effect of greater MEC on CRF to prevent the development of new-onset MetS before midlife.

Dietary Zinc Intakes Are Associated With Skeletal Muscle Mass and Strength in Children and Adolescents: Zinc and Muscle in Children

The purpose of this study was to evaluate the relationship between dietary zinc intakes and skeletal muscle mass and strength in children and adolescents. A retrospective study was conducted using data on United States adolescents aged 8 to 19 years. Data were extracted from the National Health and Nutrition Examination Survey 2011-2014 cycles. Subjects were divided into 3 groups based on the tertiles of dietary zinc intakes. The levels of appendicular skeletal muscle mass divided by weight (ASM/Wt, %) and grip in subjects with the highest tertile were higher than those in subjects with the middle and lowest tertiles (P < .05). Dietary zinc intakes were positively correlated with ASM/Wt (r = .221, P < .001) and grip (r = 0.169, P < .001). After a multivariate analysis, dietary zinc intakes were still significantly associated with ASM/Wt (β = 0.059, P < .001) and grip (β = 0.245, P < .001). The present study demonstrates that dietary zinc intakes were positively associated with skeletal muscle mass and strength in children and adolescents.