Comprehensive physical fitness and high blood pressure in children and adolescents: A national cross-sectional survey in China

Secular trends in physical fitness and cardiovascular risks among Chinese college students: an analysis of five successive national surveys between 2000 and 2019

Background

With increasing concerns about early-onset cardiovascular diseases, it is essential to understand the distribution of cardiovascular health among young adults. This study aimed to characterize trends in physical fitness and the prevalence of overweight/obesity (OWOB), elevated blood pressure (EBP), and their comorbidity among Chinese college students from 2000 to 2019 and to analyze the changes in their associations and subgroup differences.

Methods

Data were extracted from five cycles of the Chinese National Survey on Students' Constitution and Health (2000-2019), including 241,710 college students aged 19-22. Physical fitness indicator (PFI) was computed using standardized z-scores of forced vital capacity, sit-and-reach, 50-m dash, standing long jump, muscle strength, and endurance running. OWOB was defined as a body mass index ≥25 kg/m2, and EBP as systolic blood pressure ≥140 mmHg and/or diastolic blood pressure ≥90 mmHg. Comorbidity was defined as the co-occurrence of OWOB and EBP. Mixed-effects logistic regression was used to analyze associations, and generalized linear mixed-effects models were applied to examine dose-response relationships.

Findings

The median of college students' PFI deteriorated continuously from -0.16 in 2000 to -1.99 in 2019, with boys experiencing a faster decline than girls. The prevalence of OWOB, EBP, and comorbidity increased significantly from 3.7%, 2.2%, and 0.3% in 2000 to 14.0%, 5.2%, and 1.8% in 2019, respectively, with boys exhibiting higher prevalence than girls. Decreasing PFI levels were significantly associated with the increasing prevalence of OWOB, EBP, and comorbidity, and such associations were strongest in 2019. L-shaped curves were observed for the relationships between PFI and the prevalence of OWOB, EBP, and comorbidity, with stronger associations in boys. Provincial population attributable fraction showed that when improving the PFI levels from low to middle-low or above, college students in Guizhou, Sichuan, and Yunnan provinces exhibited the most reductions in OWOB, EBP, and comorbidity.

Interpretation

Physical fitness among Chinese college students has significantly declined over the past two decades, accompanied by marked increases in the burden of cardiovascular risks. There is an urgent need to increase the focus on college students' health and establish a college-based physical examination system to assess their long-term cardiovascular function.

Funding

The present study was funded by National Key R&D Program of China (Grant No. 2024YFC2707901 to Yi Song), National Natural Science Foundation of China (Grant No. 82273654 to Yi Song), and Beijing Office for Education Sciences Planning (Grant No. BBAA22027 to Yi Song).

Association of body mass index with muscle strength and cardiorespiratory fitness: A cross-sectional study based on Chinese adolescents

BACKGROUND

Muscle strength and cardiorespiratory fitness are important components of physical fitness and are important for the physical and mental health development of university students. However, obesity is also an important factor affecting physical fitness, and there are few studies on how body mass index (BMI), which reflects obesity, is associated with muscle strength and cardiorespiratory fitness among Chinese university students. Therefore, this study analyzed the association between BMI and muscle strength and cardiorespiratory fitness among Chinese university students in order to provide a reference and basis for promoting the development of physical fitness among Chinese university students.

METHODS

A stratified whole-group sampling method was used to test physical fitness items in 27 973 (15 527 boys, 55.51%) university students in 800 first- to fourth-year university classes in Anhui, Fujian, Xinjiang, Shanghai, and Jiangxi, China. The physical fitness items included height, weight, standing long jump, 1000 m running (boys), and 800 m running (girls) items. Curvilinear regression analysis was used to analyze the correlations that existed between BMI and standing long jump and VO2max.

RESULTS

The BMI of Chinese 19-22 years old university students was (21.14 ± 2.92) kg/m2. The mean standing long jump score was (197.31 ± 34.07) cm. In general, the BMI reached the highest point of 207.92 cm when the BMI was 26.25 kg/m2, and then showed a decreasing trend with the increase of BMI. The overall relationship between BMI and vertical jump showed an inverted "U"-shaped curve. In terms of VO2max, the overall trend of VO2max increased gradually with the increase of BMI, and when BMI reached 40 kg/m2, VO2max was 4.34 L-kg-1-min-1.

CONCLUSION

Chinese university students showed an inverted "U" curve relationship between BMI and standing long jump in general, while VO2max showed a gradual increase with increasing BMI. Compared with the cardiorespiratory fitness of Chinese university students, the effect of BMI changes on muscle strength was greater.

Forced vital capacity and body mass index of Xinjiang children and adolescents: an analysis based on seven successive national surveys, 1985-2014

BACKGROUND

Pulmonary function is very important for the healthy development of children and adolescents. However, fewer studies have been conducted on pulmonary function trends in children and adolescents in remote areas. The aim of this study was to estimate the forced vital capacity (FVC) trend and its relationship with body mass index (BMI) among young people in Xinjiang during 1985-2014 using data from seven successive national surveys.

METHODS

A total of 19,449 Xinjiang children and adolescents aged 7-18 years were extracted from the Chinese National Survey on Students' Constitution and Health. Height, weight, and FVC were measured repeatedly in each survey. FVC comparisons between adjacent surveys by age and sex were conducted by nonparametric Kruskal-Wallis after Kolmogorov-Smirnov of normality. One-way ANOVA and least significant difference(LSD) method was used to compare differences in FVC levels of Xinjiang children and adolescents with different BMI. The relationship between BMI and FVC was investigated using a nonlinear regression model.

RESULTS

The FVC levels of Xinjiang children and adolescents peaked in 2000, with overall FVC levels being 8.7% higher in 2000 than in 1985. Since then, a substantial decline occurred, contrasting to 2000, with FVC levels decreasing by 27% in 2014, which was still lower than that in 1985 by 20.73%. The proportion of overnutrition boys increased from 0.2% in 1985 to 22.1% in 2014, and girls from 0.5% in 1985 to 14.5% in 2014. An inverted U-shape association between FVC and BMI values was obtained for Xinjiang children and adolescents.

CONCLUSIONS

Targeted measures should be carried out in schools to control BMI levels to ensure good lung function in children and adolescents in Xinjiang. Future studies should pay more attention to other factors affecting FVC, such as dietary behaviour, physical activity, and racial differences among children and adolescents.

Cardiovascular Risk Factors in China

The Annual Report on Cardiovascular Health and Diseases in China (2022) intricate landscape of cardiovascular health in China. This section dissects cardiovascular risk factors in China which including hypertension, dyslipidemia, diabetes mellitus, chronic kidney disease, metabolic syndrome and air pollution. Hypertension prevalence has steadily increased in China, with efforts to control it facing challenges in achieving optimal rates, especially in rural areas. Interventions like salt substitutes and intensive blood pressure control show promise but need improvement. Abnormal lipid levels, indicative of dyslipidemia, have risen significantly, posing a risk for cardiovascular diseases. Despite efforts, many patients struggle to achieve target lipid levels, necessitating improved treatment strategies. Both type 1 and type 2 diabetes mellitus affect millions of adults in China, with long-term complications adding to the disease burden. Early intervention and effective management are crucial to mitigate its impact. Prevalent among older adults, chronic kidney disease is associated with diabetes mellitus, hypertension, and cardiovascular diseases, necessitating comprehensive management approaches. The prevalence of metabolic syndrome, characterized by a cluster of risk factors, has increased in both adults and adolescents, calling for lifestyle modifications and public health interventions. Ambient and household air pollution remain significant environmental risk factors, despite some improvements in air quality. Continued efforts to reduce emissions are essential for mitigating associated health risks. Addressing these risk factors requires a multifaceted approach, including public health initiatives, policy interventions, and individual-level strategies to promote healthy lifestyles and reduce environmental exposures. Surveillance and research efforts are crucial for monitoring trends and developing effective strategies to lessen the burden of cardiovascular diseases in China.

Influencing Factors on Cardiovascular Health in China

The Annual Report on Cardiovascular Health and Diseases in China (2022) intricate landscape of cardiovascular health in China. This is the first section of the report, which dissects influential factors across diverse domains. The investigation identifies tobacco use as a paramount concern, portraying China as the global epicenter of tobacco consumption. Cigarette smoking, exacerbated by second-hand smoke exposure, emerges as a critical and preventable risk factor, contributing to a surge in attributable deaths over the past three decades. In the realm of dietary nutrition, the study discerns an overall improvement, yet discerns worrisome deviations, notably an escalating fat intake surpassing recommended guidelines. The shifting dietary structure reveals diminished consumption of cereals and vegetables juxtaposed with an uptick in animal foods, while excessive intake of cooking oil and salt persists, straying substantially from endorsed levels. The exploration of physical activity patterns unfolds a nuanced narrative. Varied trends are observed among students, with concerns arising from sedentary behaviors and inadequate adherence to recommended guidelines. The analysis spans a trajectory of declining physical activity in Chinese adults, coupled with an alarming surge in sedentary leisure time, ultimately linking these factors to heightened risks of cardiovascular diseases and increased adiposity. An examination of overweight and obesity trends uncovers a relentless upward trajectory, projecting substantial prevalence by 2030. Noteworthy prevalence rates underscore the imperative for targeted interventions to curtail this burgeoning health crisis, with the anticipated prevalence extending to nearly two-thirds of the adult population. Psychological factors, notably depression, constitute an integral facet of cardiovascular health. Prevalence rates among patients with coronary artery disease and acute myocardial infarction underscore the intricate interplay between mental health and cardiovascular outcomes. Additionally, persistent depressive symptoms are shown to significantly elevate the risk of cardiovascular diseases and mortality. This first section underscores the multifaceted challenges facing cardiovascular health in China, emphasizing the imperative for tailored interventions across tobacco control, dietary habits, physical activity, obesity management, and psychological well-being to mitigate the escalating burden of cardiovascular diseases in the population.

Temporal trends in physical fitness among Chinese children and adolescents from 2000 to 2019 and analysis of social-ecological factors

This study aimed to estimate temporal trends in physical fitness (PF) by regions, age groups and nutritional status among Chinese children and adolescents and to longitudinally examine PF determinants based on social-ecological model. Participants (n = 68,265) aged 7-18 were from five successive national surveys (2000 to 2019). Six tested items of PF were calculated as PF indicator (PFI), which was used to divide participants into two categories: low vs. moderate/high. One-way analysis of variance was used to compare difference and change trend of PFI. Linear regression evaluated relationship between PFI and body mass index (BMI), and logistic regression assessed association between PFI and factors of behaviours and lifestyles on individual-, family- and school-level based on the social-ecological model. PFI declined sharply from 2000 to 2010, increased slightly from 2010 to 2014 and then edged down in 2019. Students with moderate BMI and students in urban areas tended to have higher PFI, and larger increase of PFI was found in students aged 7-9 and 13-15 after 2010. Several determinants on individual-, family- and school-level related to PFI. Efforts to develop PF mainly include increasing PA and reducing sedentary behaviours by facilitating home-school collaboration and emphasizing age-, region- and BMI-specific actions.

The association between various dimensions of sleep parameters and mental health: A large cross-sectional study of 13554 Chinese students

OBJECTIVES

We aimed to investigate the association between multiple sleep variables and mental health among Chinese students aged 9-22.

METHOD

We stratified the included 13,554 students by educational levels. Sleep parameters contained sleep duration on school days and weekends, napping time, chronotype and social jetlag (SJL), which were calculated via questionnaires. Individual psychological well-being and distress were assessed by Warwick-Edinburgh mental Well-being scale and the Kessler Psychological Distress Scale 10 respectively. The multiple linear and binary logistic regression were applied to analyze the association of sleep with mental health.

RESULTS

Short sleep on school days showed significantly positive association with psychological problems. While among senior high school students, we found reverse result that sleeping less might negatively associated with more severe distress (7-8 h: aOR = 0.67, 95% CI: 0.46, 0.97). The association of sleep duration with mental health was attenuated a lot on weekends. The chronotype was significantly related with mental health in primary and junior high school: intermediate chronotype (vs late chronotype) was associated with greater wellbeing (β = 1.03, 95% CI: 0.09, 1.96; β = 1.89, 95% CI: 0.81, 2.97) and less distress (aOR = 0.78, 95% CI: 0.60, 1.00; aOR = 0.73, 95% CI: 0.58, 0.91). The relationship between SJL, napping duration and psychological health problems were also observed in some educational levels.

CONCLUSION

Sleep deprivation on school days, late chronotype and SJL were positively associated with worse mental health in our study, which differed among various educational stages.

Effects of behaviors and surrounding environment on myopia before and during the COVID-19 pandemic: a longitudinal analysis of children and adolescents in China

Aim

To investigate the relationship between related factors and visual acuity of Chinese school students before and during the COVID-19 pandemic.

Subject and methods

Chinese students from primary and secondary schools were included from the Chinese National Surveys on Students' Constitution and Health CNSSCH (2019). A total of 1496 participants completed follow-ups in June and December 2020, respectively. Generalized estimating equations were used to test the differences in visual environment. Logistic regression models were utilized to examine the roles of behaviors and surrounding environment changes associated with myopia before and during the pandemic.

Results

The prevalence of myopia was 47.7%, 55.6%, and 57.2% in baseline and two follow-ups, respectively. Significant differences existed for gender, learning level, and region (all P < 0.05). The proportion of new myopia and myopia torsion was the highest in the primary schools. Multivariate logistic regression analysis found that screen time ≥ 4h/d (OR = 2.717), poor eye habits (OR = 1.477), insufficient lighting for studying at night (OR = 1.779), desk or roof lamps only (OR = 1.388), and poor sleep quality (OR = 4.512) were the risk factors for myopia (all P < 0.05), and eye exercises (OR = 0.417), milk intake (OR = 0.758), and eggs intake (OR = 0.735) were the protective factors for myopia (all P < 0.05).

Conclusion

Prevalence of myopia increased among Chinese students before and during the COVID-19. It is necessary to pay more attention to the pupils' visual acuity, especially in primary school students, in the future.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10389-023-01900-w.

Utility of a Physical Fitness Score in Screening for Chronic Diseases

We developed a new Physical Score (PS) consisting of comprehensive physical fitness indicators and elucidated the association between the resultant PS and metabolic diseases, i.e., diabetes, hypertension, dyslipidemia, fatty liver, and metabolic syndrome (MetS), among Japanese. Analyzed were 49,850 persons (30,039 men) aged 30 to 69 y who underwent physical fitness tests. Principal component analysis was performed on the correlation matrix of the physical fitness test results (relative grip strength, single-leg balance with eyes closed, and forward bending) according to sex and age. We defined the PS as the first principal component score. A formula was developed for various age groups comprised of men and women from 30 to 69 years of age from which the PS for each age and sex was calculated. The PS for both men and women was normally distributed with a value of 0 ± 1.15-1.16. Multivariate logistic regression analysis showed that the risk of metabolic diseases increased approximately 1.1-1.6 times per each 1-point reduction in the PS. The association between PS and MetS was particularly strong in that a 1-point reduction in the PS increased the risk of MetS by 1.54 times (95% confidence interval 1.46 to 1.62) in men and by 1.21 times (1.15 to 1.28) in women. The association between a lower PS and disease risk was stronger in younger men for fatty liver and in older men for MetS. Conversely, in women, the association between a lower PS and disease risk was stronger in older women for fatty liver and in younger women for MetS. For diabetes, hypertension, and dyslipidemia, the change in the impact of PS reductions across age groups was small. The PS is a useful and simple non-invasive tool for screening Japanese people for metabolic diseases.

Physical fitness mediates and predicts for high blood pressure among children in relation to weight status

Background

Pediatric hypertension contributes to adulthood hypertension and target organ damage. Obesity is a well-known predictor for pediatric hypertension; however, the relationship between physical fitness and blood pressure (BP) is unclear among children. This study aimed to compare the differences in demographics, anthropometrics, and physical fitness across BP subgroups and investigate whether physical fitness was related to pediatric hypertension independent of weight status.

Methods

This quantitative, cross-sectional study investigated demographic, anthropometric, physical fitness, and BP measures among 360 healthy school-aged children. Continuous variables were compared across BP subgroups with the one-way analysis of variance. Mediation and moderation analyses were used to explore the mechanism. Multivariable regression models were used to assess independent associations for hypertension.

Results

There were 177 (49.2%), 37 (10.3%), and 146 (40.6%) children in the normotensive, elevated BP, and hypertensive subgroups, respectively. The hypertensive subgroup had higher body mass index (BMI) and waist/height ratio percentiles and performed worse in 800-m run, standing long jump (SLJ), and 1-min sit-ups than the normotensive subgroup. Furthermore, the 800-m run percentile (total effect: β = 0.308, standard error = 0.044, p < 0.001) and sit and reach percentile (total effect: β = 0.308, standard error = 0.044, p < 0.001) mediated the relationship between the BMI percentile and systolic BP percentile; the SLJ percentile was directly associated with the diastolic BP percentile (β,-0.197, 95% confidence interval,-0.298-0.097; p < 0.001). The parsimonious model of multivariable regression models revealed that the SLJ percentile (adjusted exp (β), 0.992, 95% confidence interval, 0.985-0.999; p = 0.042) and BMI percentile (adjusted exp (β), 1.024, 95% confidence interval, 1.016-1.032; p < 0.001) were two independent predictors for pediatric hypertension.

Conclusion

Physical fitness mediates the relationship between anthropometric and BP measures. The SLJ percentile is associated with pediatric hypertension independent of the BMI percentile. Proactive screening and health promotion for not only healthy weight status but also good physical fitness may be beneficial for BP control among school-aged students.

Effects of fundamental movement skills on health-related quality of life in Chinese school-age children: the mediating role of physical fitness level

Background

The primary purpose of this study is to analyze the relationship between school-age children's fundamental movement skills (FMS), physical fitness levels, and the health-related quality of life (HRQoL); To explore the mediating role of physical fitness levels between school-age children's FMS and HRQoL.

Methods

In the cross-sectional survey in 2021, 334 school-age children aged 6-10 (8.20 ± 1.16) were recruited from primary schools in Jinhua City, Zhejiang Province, China. Test of Gross Motor Development 2 (TGMD-2), National Standards for Students' Physical Health, and Pediatric Quality of Life Inventory TM Version 4.0 (PedsQL™ 4.0) were used to investigate the FMS, physical fitness level, and HRQoL of school-age children. Hierarchical regression was used to analyze the relationship among FMS, physical fitness levels, and HRQoL. Bootstrap is used to evaluate the mediating role of physical fitness levels in the relationship between FMS and HRQoL.

Results

The higher the FMS and physical fitness, the higher the school-age children's HRQoL, physical functioning, social functioning, and school functioning (r = 0.244-0.301, p < 0.01). In addition, developing children's FMS promotes physical fitness levels (r = 0.358, p < 0.01). The regression analysis results of controlling gender, age, and body mass index z (BMI-z) scores showed that FMS significantly positively predicted the physical functioning (β = 0.319, p < 0.01), social functioning (β = 0.425, p < 0.01), and school functioning (β = 0.333, p < 0.01) of school-age children. When the physical fitness level enters the regression equation, the absolute value of the regression coefficient of FMS decreases. However, it can still significantly predict the physical functioning (β = 0.211, p < 0.01) and school functioning (β = 0.142, p < 0.05) of school-age children. Simple intermediary analysis shows that physical fitness level plays an intermediary role between FMS, physical functioning (indirect effect = 0.089 [95% Confidence interval (CI) = 0.015,0.195]), and school functioning (indirect effect = 0.065 [95% CI = 0.007,0.150]).

Conclusion

This study shows that physical fitness levels mediate the relationship between FMS and HRQoL. Encouraging the development of FMS and promoting physical fitness levels of school-age children can effectively improve the HRQoL of school-age children.

Associations between Physical Fitness Index and Body Mass Index in Tibetan Children and Adolescents in Different High-Altitude Areas: Based on a Study in Tibet, China

Objective: To investigate the relationship between physical fitness index (PFI) and body mass index (BMI) of Tibetan children and adolescents in different high-altitude areas in Tibet, China. Methods: Using the stratified cluster sampling method, 3819 Tibetan children and adolescents from three different high-altitude areas including Nyingchi, Lhasa and Nagqu in the Tibet area of China were given grip strength, standing long jump, sitting forward bend, 50 m running and endurance running tests. One-way analysis of variance was used to compare the physical fitness index in different high-altitude areas. In addition, the method of curve regression analysis was used to analyze the relationship between PFI and BMI. Results: In general, the level of PFI in Nagqu, Tibet, China was lower than that in Nyingchi and Lhasa, and the levels of girls were generally lower than those of boys. The proportions of malnourished, normal, overweight and obese Tibetan boys in high-altitude areas were 11.8%, 79.7%, and 8.5%; those of girls were 3.3%, 82.3%, and 14.4%, respectively. The curve regression analysis showed that the model fitting of male Nyingchi, Lhasa, Nagqu and female Nyingchi, Lhasa, Nagqu were all significant (F values were 29.697, 34.709, 37.500, 9.123, 9.785, 6.939, p < 0.01). The relationship between BMI and PFI generally showed an inverted “U” curve relationship. Conclusion: The negative impact of overweight and obesity on physical fitness of Tibetan boys in high-altitude areas is significantly higher than that of girls, and the negative impact of overweight and obesity on physical fitness of boys in Lhasa and Nyingchi area is more significant than that in the Nagqu area. In the future, attention should be paid to Lhasa and the occurrence of overweight and obesity among Tibetan boys in Nyingchi area in order to prevent the sharp decline of physical fitness and promote the physical and mental development of Tibetan children and adolescents in high-altitude areas.

Gym and home-based combined training in men with primary hypertension: are they equally effective on functional fitness profile, body composition components, and biochemical parameters of hypertension?

OBJECTIVE

This study aimed to compare the effects of 10 weeks of gym versus home-based combined training on the functional fitness, body composition, and biochemical parameters of hypertension in primary hypertensive men.

METHODS

Forty-six patients (age 48 ± 9 years, BMI 30 ± 4 kg/m²) assigned into three groups: a gym-based combined training (GBCTr: n = 16; resistance at 60-80% of 1RM, using pin-loaded resistance equipment, aerobic at 40-60% HRR, and stretching), home-based combined training (HBCTr: n = 15; resistance at 12-15 RPE, using an elastic exercise band, aerobic at 40-60% HRR, and stretching), and control (CTR, n = 15).

RESULTS

Following GBCTr and HBCTr, the functional aerobic capacity (P = .005 and P = .004, respectively), flexibility (P = .01 and P = .004, respectively), and lower limb muscle strength (P = .01 and P = .02, respectively) was increased significantly compared with the CTR group. The body weight (P = .02), body mass index (P = .008), hip circumference (P = .02), and nitric oxide level in GBCTr and HBCTr group (P = .002 and P = .02, respectively) was decreased significantly compared with the CTR group. No significant changes found in the plasma levels of NADPH oxidase 5, thioredoxin-2, thioredoxin reductase-2, and resting blood pressure after GBCTr and HBCTr compared with the CTR group.

CONCLUSION

These results suggest that in hypertensive men, HBCTr equally to GBCTr improved functional fitness and body composition remarkably without necessarily reducing resting blood pressure. Therefore, they can be advisable substitutes for gaining health benefits.

Urban-Rural Differences in Physical Fitness and Out-of-School Physical Activity for Primary School Students: A County-Level Comparison in Western China

Rapid urbanization of China has brought lifestyle changes resulting in a continuous decline in children's physical fitness (PF) and out-of-school physical activity (PA). To date, studies have been focused on correlates of PF and out-of-school PA, and patterns and trends based on geographic diversity and urban-rural contrasts. Western China, with a large rural population, has substantial urban-rural differences, but little work has been done to compare its children's physical fitness (PF) and out-of-school physical activity (PA) at a county level. A total of 715 primary school students (grades 3-6) were surveyed from one urban school (n = 438) and four rural schools (n = 277) in a county-level administrative unit, Yangling District, Shaanxi, in western China. Physical fitness index (PFI) was measured and calculated based on the revised Chinese Student Physical Fitness Standards. Out-of-school PA and other variables of demographics, behavior and perception were collected using questionnaires. Statistical analyses explored urban-rural differences and correlates of PFI and out-of-school PA. We found that the PFI (72.86 vs. 79.67) and weekly moderate-to-vigorous physical activity (MVPA) duration (167.57 vs. 220.08) of urban students were significantly lower than those of rural students. Weekly MVPA duration had the largest positive impact on PFI. Perceived availability of PA spaces was positively associated with both the urban and rural students' PF and PA, while screen time was negatively associated with PF and PA, especially for rural students. Facilitators of PA frequency include the perceived availability of PA time and parental educational level. Parents' PA habits had a positive impact on urban students' PA. No association between active school commuting and PF or PA was found. Our findings revealed that PF and out-of-school PA of urban students were clearly lower than among rural students. The health of rural children at the county level in western China should be paid much more attention during the process of rapid urbanization.

Individual-, Family-, and School-Level Ecological Correlates With Physical Fitness Among Chinese School-Aged Children and Adolescents: A National Cross-Sectional Survey in 2014

Introduction: Few studies have examined the association between the individual-, family-, and school-level ecological correlates and physical fitness among Chinese children and adolescents, which is the purpose of the present study. Methods: A total of 157,168 children and adolescents, 10-18 years of age, with physical fitness data in 2014, participated in the study. Physical fitness was assessed, using six tests: forced vital capacity, standing long jump, sit and reach, body muscle strength, 50-m dash, and endurance running. Scores were aggregated to form a summary physical fitness indicator (PFI), which was then classified into five levels: low, low-middle, middle, middle-high, and high. Each option of individual-, family-, and school-level measures were constructed into a positive or negative correlate of physical fitness and then accumulated as a composite ecological score. Results: Among the 20 individual-, family-, and school-level correlates, 18 were found to be significantly associated with PFI, with high PFI levels being correlated with the positive group of correlates and low PFI levels correlated with the negative group of correlates (p < 0.05). High scores of ecological correlates were associated with a high level of PFI [adjusted odds ratio (OR) = 1.06, 95% CI: 1.06, 1.07)] whereas low scores were associated with a low level of PFI (OR = 0.95, 95% CI:0.95, 0.95). The ecological correlates at the individual, school- and family-levels were shown to be significantly related to high PFI among Chinese children and adolescents aged 10-18 years with different ORs of 5.97 (95% CI: 5.51, 6.47), 3.94 (3.66, 4.24), and 1.25 (1.19, 1.31). The PAR% of 20 cumulative factors effects due to the negative and positive responses for low PFI levels were 35.9 and 16.1%, and, for high PFI levels, were 15.3 and 24.1%, among Chinese children and adolescents, respectively. Compared with the correlates at family and school levels, the correlates at individual levels had the largest PAR%. Conclusion: Individual-, family-, and school-multilevel factors had a significant cumulative association with either improving or worsening aspects of physical fitness. Individual level factors remain at the core of physical fitness improvement. Comprehensive policies and measures are urgently needed to enhance the physical fitness of Chinese children and adolescents through involving further individual and environmental factors.

The association of physical fitness with mental health in children: A serial multiple mediation model

There is growing interest in the association between physical fitness and mental health. This study aimed to extend current knowledge by investigating the potential mediating roles of resilience and anxiety in the association between physical fitness and mental health in children. A total of 269 children were selected by stratified random sampling from three primary schools in China. Physical fitness was scored using the Chinese National Student Physical Fitness Standard. Resilience, anxiety, and mental health data were collected using the following questionnaires: Resilience Scale for Chinese Adolescents, Multidimensional Anxiety Scale for Children, and the Mental Health Test. The PROCESS macro developed by Hayes was used to conduct serial multiple mediation analysis. We found that physical fitness, resilience, anxiety, and mental health were significantly correlated. Children with higher physical fitness had lower mental health problems; however, this statistical significance was not detectable after controlling for resilience and anxiety. Serial multiple mediation analysis revealed that the association of physical fitness with mental health was partially mediated by resilience and anxiety. These results indicate that the positive association of physical fitness with mental health in children may be changed through resilience and anxiety, which appear to play serial multiple mediating roles in this association. These findings contribute to deeper understanding of the associations between these factors and suggest that promoting physical fitness independent of considering resilience and anxiety may be insufficient to achieve good mental health in children.