This study aimed to explore the impact of environmental factors such as latitude, altitude, family socioeconomic status (SES), and level of urbanization on overweight and obesity (ow/ob) in children and adolescents. The participants comprised 26,120 children and adolescents aged 10–18 from 16 provinces in China. Differences in the prevalence of ow/ob under different environmental conditions were evaluated by the chi-square test. The influence of various environmental factors on ow/ob was obtained by logistic regression analysis. We found that (1) the prevalence of ow/ob fell between from 19.2% to 11.9% at 10 years old and from 13.8% to 6% at 18 years old; (2) latitude, family SES, income, and urbanization level are positively correlated with the prevalence of ow/ob; and (3) altitude has a negative correlation with the prevalence of ow/ob. The prevalence of ow/ob decreased with age in children and adolescents aged 10–18, and the risk of ow/ob showed significant differences in latitude, altitude, family SES level, gross domestic product (GDP), and level of urbanization.

This study compared the physical fitness level and weight status of children and adolescents in China and Japan. Children and adolescents aged 7–18 years were recruited (China: n = 5660; Japan: n = 5660). Physical fitness was assessed using seven core items—grip strength, 30-s sit-ups, standing long jump, sit-and-reach, 20-s repeated straddling, 20-m shuttle run test, and 50-m dash. A physical fitness index (PFI) was calculated by adding all items’ Z-scores. We conducted comparisons of PFI and its distribution, each physical fitness item, and weight status for individuals from China and Japan across all ages. The PFI was lower in China than in Japan for all age groups, with an especially large difference at age 18 years for boys (a difference of 9.05) and girls (a difference of 9.10) (p < 0.001). The same result was seen for the seven items. The PFI distribution for children and adolescents was more disperse among those in Japan than among those in China. Obesity prevalence was 2.84 times higher in China than in Japan. An inverted U-shaped relationship was observed between physical fitness and nutritional status. Children and adolescents showed markedly lower physical fitness and higher obesity prevalence in China than in Japan.

Background: Since there is little knowledge about the 24-hour movement behaviors of Chinese children and adolescents, the purposes of this study were to investigate the proportion of Chinese children and adolescents meeting the 24-Hour Movement Guidelines and to further evaluate its relationship with overweight and obesity. Methods: A total of 440 children and adolescents aged 7–18 years from 7 cities in China were selected to measure physical activity using accelerometers, and sleep (SLP) and screen time (ST) using questionnaires. The data were analyzed with the independent T-test, Mann–Whitney U test, Cox–Stuart test, chi-square test, and logistic regression. Results: The proportion of Chinese children and adolescents meeting the overall 24-Hour Movement Guidelines was 7.3%. Boys (11.8%) were higher than girls (3.4%) (p < 0.001) and showed a downward trend with age (P_trend = 0.03). The rates of overweight and obesity among children and adolescents who met the ST, MVPA + ST, ST + SLP, and MVPA + SLP + ST guidelines were 39%, 15%, and 36%, and 25% did not meet any guidelines. The rates of overweight and obesity among those who met 1, 2, and 3 guidelines were lower than the rate among those who did not meet any guidelines (odds ratio (OR) = 0.51, 95% confidence interval (CI): 0.22–1.17; OR = 0.32, 95% CI: 0.13–0.77; OR = 0.23, 95% CI: 0.07–0.81) and showed a decreasing trend (P_trend = 0.006). Conclusions: The proportion of Chinese children and adolescents meeting the overall 24-Hour Movement Guidelines was low. The rate of overweight and obesity among children and adolescents who met the overall 24-Hour Movement Guidelines was the lowest compared with the rates among those who met any one or two. There was a dose–response relationship between the number of guidelines met and the overweight and obesity rate.

Background: To investigate the association between family socioeconomic status (SES) and the physical activity (PA) levels of adolescents, as well as the moderating effect of gender on this relationship.Methods: A total of 10,327 Chinese adolescents aged 12–17 were recruited to complete questionnaires regarding their SES and PA levels. “Physical Activity Questionnaire for Children and Adolescents Aged 7–18 Years” was utilized to examine the specific items, intensity, duration, and frequency of PA. The Kruskal–Wallis test and the Mann–Whitney U test were employed to compare PA time among adolescents across different groups. To analyze the interaction effect between gender and SES, the Scheirer-Ray-Hare test was conducted using R software. Additionally, SPSSAU was utilized to examine the moderating effect of gender and SES on PA.Result: (1) Different intensities of PA: Overall, the times for LPA, MPA, VPA, MVPA, and TPA in the low SES group were 190 (100, 400) minutes, 190 (80, 400) minutes, 60 (0, 160) minutes, 290 (150, 570) minutes, and 580 (345, 925) minutes, respectively.The duration of PA at each intensity level in the low SES group was significantly lower compared to that in the middle and high SES groups (all P-values < 0.05). (2) Different PA types: The low SES group exhibited the shortest durations for both transportation PA (260 min) and exercise PA (155 min), while household PA was the longest (15 min)(all P-values < 0.05). (3) Moderating effect test: After controlling for relevant variables, the interaction term coefficient between gender and SES was statistically significant (B = −19.141, t = −2.059, P &lt; 0.05).Conclusion: Adolescents from low SES backgrounds exhibited the lowest levels of MVPA and TPA, which were mainly manifested in transportation PA and exercise PA. Gender moderates the relationship between SES and MVPA, with different SES levels having a more pronounced effect on PA in boys than in girls.

This article assessed the relationship between waist circumference (WC) and cardiorespiratory fitness (CRF) of children and adolescents aged 7–18 years. Using a stratified cluster random sampling method, 92,574 children and adolescents (47,364 males and 45,210 females) were extracted. CRF was measured by performance in the 20 m shuttle run test (20mSRT) and the subsequent estimation of maximal oxygen consumption ($\dot{\text{V}}$O_2max) using the Léger equations. Participants were divided into five groups of WC percentiles and three groups of CRF percentiles by the Lambda Mu Sigma (LMS). The correlation between WC and CRF was examined by one-way ANOVA and curvilinear regression analysis. WC increased with age, while $\dot{\text{V}}$O_2max showed an age-related decline. Controlling for gender, urban, and rural factors, for children and adolescents aged 10–12, 13–15, and 16–18 years, the $\dot{\text{V}}$O_2max Z-score of the normal WC group was significantly higher than the very low WC group (P < 0.05). Controlling for gender, urban, and rural factors, for participants aged 7–18 years, the $\dot{\text{V}}$O_2max Z-score of the normal WC group was significantly higher than the high WC group and the very high WC group (P < 0.05). It generally shows a “parabolic” trend between WC-Z and $\dot{\text{V}}$O_2max-Z. The CRF among children and adolescents in the normal WC group is significantly higher than that in the low and the high WC groups.