Matching actions to needs: shifting policy responses to the changing health needs of Chinese children and adolescents.

China is home to the second largest population of children and adolescents in the world. Yet demographic shifts mean that the government must manage the challenge of fewer children with the needs of an ageing population, while considering the delicate tension between economic growth and environmental sustainability. We mapped the health problems and risks of contemporary school-aged children and adolescents in China against current national health policies. We involved multidisciplinary experts, including young people, with the aim of identifying actionable strategies and specific recommendations to promote child and adolescent health and wellbeing. Notwithstanding major improvements in their health over the past few decades, contemporary Chinese children and adolescents face distinct social challenges, including high academic pressures and youth unemployment, and new health concerns including obesity, mental health issues, and sexually transmitted infections. Inequality by gender, geography, and ethnicity remains a feature of health risks and outcomes. We identified a mismatch between current health determinants, risks and outcomes, and government policies. To promote the health of children and adolescents in China, we recommend a set of strategies that target government-led initiatives across the health, education, and community sectors, which aim to build supportive and responsive families, safe communities, and engaging and respectful learning environments. TRANSLATION: For the Chinese translation of the abstract see Supplementary Materials section.

Combined Effect of Outdoor Time and Other Modifiable Factors on Myopia Incidence Among Children and Adolescents - 9 PLADs, China, 2020.

What is already known about this topic?: Myopia has been identified as a significant emerging challenge and policy priority among children and adolescents in China by the Ministry of Education and seven other departments. Limited research has been conducted to investigate the collective impact of outdoor time and other modifiable factors on the incidence of myopia. What is added by this report?: This study provides support for the protective effect of combining increased outdoor time with other prevention strategies in reducing the incidence of myopia. The results indicate the presence of a dose-response relationship. What are the implications for public health practice?: To effectively prevent myopia, it is important to implement comprehensive interventions that encompass various aspects such as outdoor time, eye-use habits, eye-use environments, and lifestyle modifications.

Clustering of Multilevel Factors Among Children and Adolescents: Associations With Health-Related Physical Fitness.

BACKGROUND: To identify the clustering characteristics of individual-, family-, and school-level factors, and examine their associations with health-related physical fitness. METHODS: A total of 145,893 Chinese children and adolescents aged 9-18 years participated in this cross-sectional study. The 2-step cluster analysis was conducted to identify clusters among individual-, family-, and school-level factors. Physical fitness indicator was calculated through sex- and age-specific z scores of forced vital capacity, standing long jump, sit-and-reach flexibility, body muscle strength, endurance running, and body mass index. RESULTS: Three, 3, and 5 clusters were automatically identified at individual, family, and school levels, respectively. Students with low physical fitness indicator were more likely to be in the "longest sedentary time and skipping breakfast" cluster (odds ratio [OR] = 1.18; 95% confidence interval [CI], 1.12-1.24), and "physical inactivity and insufficient protein consumption" cluster (OR = 1.07; 95% CI, 1.02-1.12) at individual level, the "single children and high parental education level" cluster (OR = 1.15; 95% CI, 1.10-1.21), and "no physical activity support and preference" cluster (OR = 1.30; 95% CI, 1.25-1.36) at family level, and the "physical education occupied" cluster (OR = 1.06; 95% CI, 1.01-1.11), and "insufficient physical education frequency" cluster (OR = 1.16; 95% CI, 1.08-1.24) at school level. Girls were more vulnerable to individual- and school-level clusters, while boys were more susceptible to family clusters; the younger students were more sensitive to school clusters, and the older students were more susceptible to family clusters (P-interaction < .05). CONCLUSIONS: This study confirmed different clusters at multilevel factors and proved their associations with health-related physical fitness, thus providing new perspective for developing targeted interventions.

Associations between combinations of 24-h movement behaviors and physical fitness among Chinese adolescents: Sex and age disparities.

OBJECTIVE: To analyze the relationship between 24-h movement behaviors and adolescents' physical fitness, with sex difference and age disparity explored specifically. METHODS: A total of 135 852 Chinese adolescents aged 13-22 years were included in this cross-sectional study. Self-reported 24-h movement behavioral times, including moderate to vigorous physical activity (MVPA), recreational screen, and sleep, were identified as meeting guidelines based on Canadian recommendations. Physical fitness indicator (PFI) was calculated through sex- and age-specific z scores of body mass index, forced vital capacity, 50 m dash, sit-and-reach, standing long jump, body muscle strength, and endurance running, and then classified as: low level (<20th), middle level (20th-80th), and high level (>80th). Mixed effect logistic regression was applied to analyze the association, and interaction terms were constructed to prove the sex and age disparities. RESULTS: Only 12.4% of adolescents aged 13-22 years met all three recommendations. The number of meeting guidelines exhibited a typical dose-response relationship with high level PFI (OR = 1.22 [95% CI: 1.19-1.25]), and in detail, meeting MVPA + recreational screen (OR = 2.29 [95% CI: 2.09-2.51]) or MVPA-only (OR = 2.16 [95% CI: 1.93-2.41]) guidelines were better associated with high-level PFI. Besides, meeting MVPA-only guideline was proved with stronger association with high-level PFI for boys (p-interaction = 0.005). The dose-response relationship in boys of the number of guidelines met with PFI was stronger in 19- to 22-year-olds (p-interaction <0.001) and 16- to 18-year-olds (p-interaction = 0.001) than that in 13- to 15-year-olds. CONCLUSION: The prevalence of meeting 24-h movement behaviors guidelines among Chinese adolescents aged 13-22 years was relatively low. It was associated with adolescents' physical fitness, with meeting MVPA + recreational screen or MVPA-only guidelines bringing greater benefits, and sex difference and age disparity existing.

Secular trends and urban-rural disparities in the median age at menarche among Chinese han girls from 1985 to 2019.

BACKGROUND: Menarche is a substantial milestone of female puberty. Timing of age at menarche is considered the key to understanding the potential linkages with women's health outcomes later in life. This study aimed to explore the secular trends and urban‒rural disparities in the median age at menarche among Chinese Han girls from 1985 to 2019. METHODS: Data were extracted from the 1985, 1995, 2005, 2014, and 2019 Chinese National Surveys on Students' Constitution and Health, which were nationally representative cross-sectional studies, and a total of 173,535 Han girls aged 9-18 years were examined. Girls were asked whether menarche had occurred. The median age at menarche was estimated by probit analysis. Z tests were used to compare the differences between survey years and between urban and rural areas. RESULTS: The median age at menarche among Chinese Han girls decreased from 13.37 years in 1985 to 12.00 years in 2019, and the overall decrease was more significant in rural areas (1.77 years) than in urban areas (0.99 years). The average five-year change in the decrease in the median age at menarche showed an accelerating and then slowing pace; and it was observed similarly in both urban and rural areas. The urban‒rural disparities shrank from 0.64 years in 1985 to 0.44 years in 1995, then to 0.27 years in 2005, 0.24 years in 2014, and finally to - 0.14 years in 2019. CONCLUSIONS: The median age at menarche among Chinese Han girls continued to decline from 1985 to 2019 but at a slowing pace in the last five years. Urban‒rural disparities gradually narrowed. Sexual and reproductive health education and interventions to prevent the decline in the age of menarche are needed, especially in rural areas.

Secular trend and urban-rural disparity for age at spermarche among Chinese Han boys from 1995 to 2019.

AIM: To examine the secular trend and the urban-rural disparity of spermarche among Chinese Han boys from 1995 to 2019. METHODS: A total of 392 775 boys of Han ethnicity aged 11-18 years were extracted from the 1995, 2000, 2005, 2010, 2014 and 2019 Chinese National Surveys on Students' Constitution and Health. The median age at spermarche was estimated using the status quo data and probit analysis. The chi-square, ANOVA and LSD tests were used to compare the differences between the year-subgroups. U-test was used to compare the difference between urban and rural areas at each year. RESULTS: The median age at spermarche in Chinese Han boys decreased from 14.6 years in 1995 to 13.9 years in 2019 (p < 0.001). The rural boys showed a faster decreasing pace with a 1-year advance of age at spermarche while the urban boys had only a 0.5-year decrement, and there was still a statistically significant difference between urban-rural areas in 2019 (p < 0.001). Similar to urban-rural disparity, the age gap at spermarche between areas with different urbanisation rates became smaller over time. CONCLUSIONS: In general, spermarche in Chinese Han boys showed a decreasing trend, but the pace was slowing down. The urban-rural disparity in puberty development still existed but was gradually narrowing.

Physical fitness and health status and gender differences of middle school students among five Chinese minorities during 2010 to 2019 / 中国学校卫生

Objective@#To analyze physical fitness and health status and gender differences of middle school students among 5 minorities (Mongolian, Hui, Uyghur, Zhuang and Korean), and to provide the theoretical basis for the strategy formulation.@*Methods@#The present data came from 3 waves of Chinese National Survey on Students Constitution and Health (2010, 2014, and 2019). According to National Standards for Students Physical Health (2014 Revision), excellent, and excellent good physical fitness and health status were defined. Cochran Armitage test was used to examine the trends of physical fitness and health status. Chi square test and Logistic regression were used to analyze the difference of physical fitness and health status by sex and survey year.@*Results@#From 2010 to 2019, the excellent physical fitness and health status rate of Mongolian, Hui, Uyghur, Zhuang and Korean students increased from 1.8%, 0.7%, 0.3%, 0.5% and 1.3% to 4.3%, 2.8%, 1.2%, 1.3% and 3.5%, respectively. The excellent good physical fitness and health status rate of Mongolian, Hui, Uyghur and Zhuang students increased from 12.9%, 8.0%, 7.2 % and 8.4% to 24.7%, 20.1%, 12.6% and 19.8%( Z =6.15，6.71，4.12，3.06，5.26；11.88，13.42，6.70，11.08， P <0.05), respectively. In 2019, students aged 13 to 15 years showed higher proportion of excellent/excellent good physical fitness and health status than that of students aged 16 to 18. Boys were more likely to be in excellent/excellent good physical fitness and health status than girls from 2010 to 2019. The sex difference in excellent/excellent good physical fitness and health status narrowed during 2010 and 2019.@*Conclusion@#Physical fitness and health status of minority students improved while sex difference narrowed during last decade, but there is still a long way to reach the goal proposed by China. Targeted intervention should be proposed to promote physical fitness and health status in accordance with the developmental characteristics, especially for girls and students aged 16 to 18 years.

Coverage of school health monitoring systems in China: a large national cross-sectional survey.

BACKGROUND: There is growing interest in the role that schools can play in promoting student health. The aim of this study was to describe the coverage of school health monitoring systems for infectious diseases, non-communicable diseases, and school physical environments in China, and to explore differences by geography, regional wealth, and school type. METHODS: A cross-sectional study was performed using data from 2428 schools from 17 provinces in China in 2018. Data were collected using a questionnaire administered by the Ministry of Education through its monitoring system, and included infectious diseases (e.g., reporting system for student infectious diseases), non-communicable diseases (e.g., regular student health examinations), and school physical environments (e.g., monitoring of classroom light, microclimate and drinking water). FINDINGS: Overall, the coverage rate of full school health monitoring systems was 16·6%. The coverage rates of school health monitoring systems for infectious diseases, non-communicable diseases, and school physical environments were 71·2%, 68·5%, and 24·9%, respectively. Coverage was higher in schools from urban rather than rural areas, in schools from areas with greater wealth, and in senior secondary schools rather than junior secondary and primary schools. INTERPRETATION: Systems for monitoring infectious diseases in school students have been widely implemented in China. Systems for monitoring non-communicable diseases and physical environments need to be strengthened. Beyond greater attention in poorer and rural areas, increased investment in more comprehensive approaches to school health is indicated. FUNDING: This study was supported by National Statistical Science Research Project (2021LY052 to YS) and China Scholarship Council (201906015028 to PH).

National School-Based Health Lifestyles Intervention in Chinese Children and Adolescents on Obesity and Hypertension.

Introduction: This study aimed to examine the effectiveness of the national school-based intervention on both obesity and high blood pressure in Chinese children and adolescents aged 6-18 years. Methods: The national school-based cluster non-randomized controlled trial was done in seven provinces from September 2013 to February 2014. A total of 23,175 children and adolescents in the control group and 25,702 in the intervention group were included in this trial with a mean follow-up of 6.7 ± 0.9 months. Mixed-effects regression models were used to evaluate the effect of the interventions on body weight and blood pressure (BP). Results: A significant upward in the body mass index (BMI) levels but downward in systolic BP (SBP), diastolic BP (DBP), BMI Z-scores, SBP Z-scores, and DBP Z-scores were witnessed in the intervention group compared to those in the control group (<0.001). Subgroup analyses presented significant intervention effects in children aged 6-12 years for BMI, SBP, DBP, and their standardized values Z-scores, but no effective results were found in adolescents aged 13-18 years. Stratification analyses based on the dynamic weight changes presented non-differential HBP, SHBP, and DHBP prevalence gaps between the control and intervention groups. Children aged 6-12 years with higher BMI percentiles at baseline presented obvious declines in SBP and DBP standardized values Z-scores. Conclusion: A mean 6-month multi-centered school-based comprehensive obesity intervention in China yields a small to null effect on obesity and hypertension with increasing age; the early age before 12 years may be the key period for interventions, and the younger, the better. Precise and high-intensity interventions targeting the population at different stages of childhood and adolescence are urgently needed to be developed. Clinical Trial Registration: https://www.clinicaltrials.gov/, identifier: NCT02343588.

The mean age of menarche among Chinese schoolgirls declined by 6 months from 2005 to 2014.

AIM: This study assessed the trends in the age at menarche in Chinese schoolgirls from the majority Han group and 21 ethnic minorities from 2005 to 2014. We also compared the group differences during the study period. METHODS: A total of 344 230 girls aged 9-18 years were extracted from the 2005, 2010 and 2014 Chinese National Survey on Students' Constitution and Health. The age at menarche for each subgroup was estimated by probit analysis. The chi-square test and Z-test were used to compare the differences between the groups. RESULTS: The overall average age at menarche in Chinese schoolgirls decreased from 12.8 years in 2005 to 12.3 years in 2014. The Han girls and girls from 17 ethnic minorities showed decreasing trends in the age at menarche, while four ethnic minorities demonstrated fluctuating increasing trends over time. The gaps in age at menarche between the Han group and 14 of the ethnic minorities became smaller over the study period and were similar by 2014. CONCLUSION: The overall findings were a decrease in the age at menarche in China and smaller gaps between the majority Han group and ethnic minority groups. Ethnic-specific public health policies are urgently needed on issues such as contraception.

Towards Comprehensive National Surveillance for Adolescent Health in China: Priority Indicators and Current Data Gaps.

PURPOSE: The purpose of the study was to propose a health indicator system responsive to current Chinese adolescent health needs and identify data gaps in current information systems. METHODS: We identified 186 keywords for adolescent health gathered from three sources: contributors to the burden of disease captured in the Global Burden of Diseases 2015, together with independent literature and expert desk reviews; major health-related policies released by the State Council of China; and global strategies issued by UN agencies over the past five years. All keywords were synthesized into indicators and ranked with core indicators identified through panel discussions and literature review. A further systematic review was conducted to identify data sources for each indicator. RESULTS: We identified 100 indicators which we categorized into five dimensions: health outcomes including adolescent mortality and morbidity; health knowledge, skills and risk behaviors including smoking, physical activity; demographic and socioeconomic status including education or employment; responsiveness of the health service system including the provision of health education at school; and the physical and social environments including safe drinking water, secondhand smoke exposure, injuries, and bullying. In total, 72 indicators had nationally representative data, including 22 out of 24 core indicators (91.7%), 27 out of 33 potential core indicators (81.8%), and 23 out of 43 general indicators (53.5%). A large proportion of these indicators rely solely on data from school or household surveys. CONCLUSIONS: The proposed health indicator system has the potential to rapidly identify shifting priorities for adolescent health in China but will require greater investment in primary data collection in neglected areas.

The association between menarche and myopia and its interaction with related risk behaviors among Chinese school-aged girls: a nationwide cross-sectional study.

Nearly 80% of new cases of myopia arise between 9 and 13 years old when puberty development also progresses rapidly. However, little is known about the association between myopia and puberty. We aim to evaluate the association between myopia and menarche, the most important puberty indicator for girls, and to test whether menarche could modify the effects of myopia-related behaviors. The participants came from two consecutive national surveys conducted in 30 provinces in mainland China in 2010 and 2014. We included 102,883 girls (61% had experienced menarche) aged 10-15 years. Risk behaviors for myopia which included sleep duration, homework time, and outdoor activity were measured by self-administrated questionnaire. Myopia was defined according to a validated method, and its relationships with menarche status and behaviors were evaluated by robust Poisson regression models based on generalized estimated equation adjusting for cluster effect of school. We found that postmenarche girls were at 13% (95% confidence interval: 11%-16%) higher risk of myopia than premenarche girls, after adjusting for exact age, urban-rural location, survey year, and four behavioral covariates. Short sleep duration (<7 h/d), long homework time (>1 h/d) and low frequency of weekend outdoor activity tended to be stronger (with higher prevalence ratios associated with myopia) risk factors for myopia in postmenarche girls than in premenarche girls, and their interaction with menarche status was all statistically significant (P < 0.05). Overall, our study suggests that menarche onset may be associated with increased risk of myopia among school-aged girls and could also enhance girls' sensitivity to myopia-related risk behaviors.

National and Subnational Trends in Mortality and Causes of Death in Chinese Children and Adolescents Aged 5-19 Years From 1953 to 2016.

PURPOSE: We aimed to analyze the recent trends of mortality and rankings of causes of death in Chinese children and adolescents from 1953 to 2016. METHODS: Data on mortality and causes of death in Chinese children and adolescents aged 5-19 years were extracted from the China Health Statistics Yearbook and the Global Burden of Disease Study from 1953 to 2016. Mortality variations were analyzed by year, age, sex, province, and causes of death. RESULTS: The mortality of Chinese children and adolescents aged 5-19 years declined steadily from 1953 (366.03/100,000) to 2016 (27.21), with the largest reduction in adolescents aged 15-19 years and the smallest reduction in those aged 10-14 years. Large subnational disparities for all-cause mortality existed in national 31 provinces with higher mortality in western regions compared with eastern regions, but with narrowing disparities between 1981 and 2010. Injuries dominated the causes of death compared with noncommunicable diseases and communicable, maternal and neonatal, and nutritional diseases from 1990 (58.13/100,000 vs. 32.10 and 14.31) to 2016 (22.65 vs. 13.00 and 2.93). In 2016, the leading three causes of death were road injuries (8.30/100,000), drowning (7.25), and leukemia (2.60). Drowning was the leading cause of death for 5- to 14-year-olds, but road injuries have been the leading cause for 15- to 19-year-olds of both sexes since 2010. CONCLUSIONS: Although mortality in Chinese adolescents now stands at just 7% of rates in the 1950s, there is a need to address continuing inequalities across sex, economic status, and region.

Ethnicity, socioeconomic status and the nutritional status of Chinese children and adolescents: Findings from three consecutive national surveys between 2005 and 2014.

BACKGROUND: Economic development has brought rapid shifts in the food environment of Chinese children and adolescents. OBJECTIVES: To assess the changes in childhood nutritional status across ethnic groups and economic status from 2005 to 2014. METHODS: 664 094 Chinese Han and 224 151 ethnic minority children and adolescents aged 7 to 18 years were assessed in three national cross-sectional surveys (2005, 2010 and 2014). Gross domestic product (GDP) per capita of each ethnic group was categorized into four strata of socioeconomic status. To assess ethnic disparities at each time point, we used logistic regression to estimate the prevalence odds ratios (OR) for thinness, overweight and obesity in the 24 ethnic minority groups vs Han Chinese. RESULTS: Children in the two upper economic strata (over about US$4000 GDP per capita) had a high prevalence of overweight and obesity, while those in the two lower economic strata (below US$4000 GDP per capita) had a high prevalence of thinness. From 2005 to 2014, the prevalence of thinness decreased from 18.6% to 13.1% in Han children, and from 20.4% to 17.1% in ethnic minority students. At the same time, the prevalence of overweight and obesity increased from 10.4% to 17.7% in Han children, and from 4.3% to 9.2% in ethnic minority students, respectively. CONCLUSIONS: A rapid nutritional transition has occurred from 2005 to 2014 with shifts from thinness to overweight and obesity in both Han and ethnic minority children and adolescents, reflecting local GDP per capita.

Reducing Anemia Among School-Aged Children in China by Eliminating the Geographic Disparity and Ameliorating Stunting: Evidence From a National Survey.

Background: The aim of this study was to assess the geographic disparity in anemia and whether stunting was associated with anemia in different geographic groups among school-aged children in China. Methods: 71,129 Han children aged 7, 9, 12, and 14 years old were extracted from the 2014 cycle of Chinese National Surveys on Children Constitution and Health. Anemia, anemia severity, and stunting were defined according to WHO definitions. Binary logistic regression models were used to estimate the association between anemia and stunting in different geographic groups. Results: The prevalence of anemia was significantly higher in girls (10.8%) than boys (7.0%). The highest anemia prevalence was in Group VII (lower class/rural, 12.0%). A moderate/severe prevalence of anemia was concentrated in Group VII and Group VIII (western/lower class/rural) for both sexes. The prevalence of anemia was higher in stunting boys than non-stunting boys in Group IV (lower class/city, χ2 = 12.78, P = 0.002) and Group VII (χ2 = 6.21, P = 0.018), while for girls, it was higher in stunting girls than their non-stunting peers only in Group II (upper class/large city, χ2 = 4.57, P = 0.046). Logistic regression showed that the stunting children have 30% higher risk of anemia than non-stunting children after adjustment for age, sex and school (OR = 1.30, 95% CI: 1.05-1.60). Conclusion: A significant geographic disparity and an association between anemia and stunting among specific groups of school-aged children in China was demonstrated. Consequently, eliminating the geographic disparity and ameliorating stunting might contribute to the improvement of Chinese children's anemia. Specific guidelines and interventions are needed, especially for adolescent girls and the groups with serious anemia burden.

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

OBJECTIVES: To assess the association between comprehensive physical fitness and high blood pressure (HBP) among Chinese children and adolescents. DESIGN: National cross-sectional surveys. METHODS: 214,301 school students' data aged 7-18years was extracted in 2014. Six components of physical fitness (forced vital capacity, standing long jump, sit-and-reach, body muscle strength, 50m dash and endurance running) were measured, standardized and aggregated as a summary physical fitness indicator (PFI). HBP, systolic HBP (SHBP) and diastolic HBP (DHBP) were defined according to sex-, age- and height-specific references in China. RESULTS: The prevalence of HBP, SHBP and DHBP was 8.6%, 4.7% and 5.7%, respectively, and PFI was -0.9 in Chinese children and adolescents. A significant negative association between the PFI and HBP was observed with adjusted prevalence of HBP (10.8% (95% CI: 10.4-11.2) to 7.6% (95% CI: 7.3-8.0), Ptrend<0.001), SHBP (5.7% (95% CI: 5.4-6.1) to 4.4% (95% CI: 4.1-4.6), Ptrend<0.001), and DHBP (7.6% (95% CI: 7.2-7.9) to 4.6% (95% CI: 4.3-4.9), Ptrend<0.001) and their ORs (HBP: 0.87(95% CI: 0.82-0.93) to 0.68(95% CI: 0.64-0.73), Ptrend<0.001; SHBP: 0.86(95% CI: 0.79-0.94) to 0.75(95% CI:0.69-0.82), Ptrend<0.001; DHBP: 0.85(95% CI: 0.79-0.92) to 0.59(95% CI: 0.54-0.64), Ptrend<0.001) declined with the increase in PFI. Stratified nutritional status exhibited a similar negative association between PFI and HBP, SHBP and DHBP in children with normal weight, overnutrition, and undernutrition. Stand long jump, body muscle strength, 50m dash, and endurance running, had a negative association with HBP, SHBP and DHBP, but forced vital capacity had a positive such association. Sit-and-reach and HBP are not significantly associated. CONCLUSIONS: Physical fitness was negatively correlated to the increased HBP in children and adolescents. Comprehensive policies and measures to enhance children and adolescents' physical fitness are urgently needed through the promotion of physical activity, healthy dietary patterns, and strategies of educational guidelines to reduce schoolwork, which will in turn reduce the cardiovascular burdens in the future.

Prevalence of Anemia and its Associated Factors among Chinese 9-, 12-, and 14-Year-Old Children: Results from 2014 Chinese National Survey on Students Constitution and Health.

Background: Anemia has been one of the main nutritional challenges around the world. Not enough attention has been paid to this issue in children and adolescents in China. In this study, we aimed to estimate the prevalence of anemia among 9-, 12-, and 14-year old Chinese children and investigate the associated factors of anemia. Methods: Data come from a cross-sectional survey conducted in 26 provinces and 4 municipalities in mainland China. A total of 48,537 children aged 9, 12, and 14 years old were included in data analyses. Anthropometric measurements were conducted to obtain information about height and weight. Capillary blood was collected from the fingertip, and hemoglobin concentration was tested by HemoCue201+. Information about sleep duration, daily consumption of eggs, milk, and breakfast were obtained from a self-administrated questionnaire. The mixed-effects logistic regression model was applied to estimate the association between selected variables and risk of anemia. Results: A total of 8.4% of participants were identified as being anemic; and the prevalence was higher in girls and rural children. Mixed-effects logistic regression analysis showed that children who were overweight, obese, and consumed eggs and milk every day had a lower risk of anemia. Spermarche, overweight/obesity, and having milk every day were associated with lower risk of anemia in boys, while menarche was found to be a risk factor and eating eggs every day to be a protective factor of anemia in girls. Conclusions: Anemia among 9-, 12-, and 14-year-old children is still high. Intervention programs of adding egg and milk into school daily diet might contribute to reducing anemia in Chinese school aged children, especially for those living in rural areas or girls with menarche.

The associations of economic growth and anaemia for school-aged children in China.

Economic growth has brought improvements in many areas of child health, but its effects on anaemia among school-aged children remain unknown. However, this is important because iron deficiency anaemia is common and is the main cause of disability-adjusted life years for school-aged children. In this study, we included 429,222 Chinese children aged 7-17 years from five consecutive national cross-sectional surveys during 1995-2014. Using altitude-adjusted haemoglobin concentration measured from capillary blood samples, we defined anaemia status according to World Health Organization's recommendation. We used logistic regressions weighted by provincial population to examine the association between provincial gross domestic product (GDP) per capita and anaemia, adjusting for sex, age, urban-rural location, regional socio-economic status (SES), fixed effect of province, and clustering of schools. We used generalised additive mixed models to evaluate a potentially non-linear relationship. For each 100% growth in GDP per capita, there was a 40% (odds ratio [OR] = 0.60; 95% confidence interval [CI; 0.56, 0.65]) reduction in anaemia. However, the association was weaker for girls and in cities with a lower SES. The association was weaker across 2005-2014 (OR = 0.75, 95% CI [0.62, 0.90]) compared with 1995-2005 (OR = 0.52; 95% CI [0.44, 0.61]), reflecting a weaker association when GDP per capita reaches around $2,000. The results were similar for moderate-to-severe anaemia. We concluded that economic growth has been associated with reductions in anaemia among school-aged children in China but with fewer benefits for girls and those in poorer settings. Further economic development in China is unlikely to bring similar reductions in anaemia, suggesting that additional population level and targeted interventions will be needed.

Trends in physical fitness, growth, and nutritional status of Chinese children and adolescents: a retrospective analysis of 1·5 million students from six successive national surveys between 1985 and 2014.

BACKGROUND: Physical fitness is strongly associated with health. Despite the extent of the nutritional transition from food scarcity to diets high in fats and refined carbohydrates that has occurred in China, to our knowledge, trends in physical fitness have not been described. We aimed to assess trends in physical fitness and its association with the nutritional transition among Chinese children and adolescents. METHODS: In this retrospective analysis, data from Chinese school students aged 7-18 years were extracted from six successive national surveys undertaken between 1985 and 2014. Six components of physical fitness (forced vital capacity, standing long jump, sit-and-reach, body muscle strength, 50 m dash, and endurance running) were measured repeatedly in each survey and aggregated as a summary physical fitness indicator (PFI). Growth and nutritional status (stunting, thinness, normal weight, overweight, and obesity) were defined by use of WHO definitions, and we combined stunting and thinness as undernutrition and overweight and obesity as overnutrition. Urbanisation levels were obtained from the statistical yearbook of the National and Provincial Bureau of Statistics of China. We used fractional polynomial regression and generalised additive models to assess associations between PFI and nutritional outcomes and between PFI and levels of urbanisation. FINDINGS: Between 1985 and 2014, 1 513 435 students participated in the Chinese National Survey on Students' Constitution and Health, and 1 494 485 were included in our study. We observed a decline of the PFI during 1985-2014 (overall PFI change -0·8), albeit with an increase from 1985 to 1995 (PFI change 1·2), coinciding with a shift in the major nutritional problems from stunting and thinness to overweight and obesity. Both undernourished (PFI -2·44 for thin and -3·42 for stunting) and overnourished (-1·49 for overweight and -3·63 for obese) students had a lower PFI than that of those with normal weight (-0·41) in 2014. Boys had a larger decline in PFI than girls in 1985-2014, especially boys with obesity (PFI change -2·7). We observed the highest PFI in 1995 (1·17), when the proportion of students with normal weight was highest. Advancing urbanisation was accompanied by declines in physical fitness, which occurred in both students in rural settings and those in urban settings in these regions. INTERPRETATION: Our study supports the continuation of policies to improve physical fitness that focus on undernutrition, including economic subsidies, in poorer rural regions. However, for most of China, taxation of unhealthy foods, promotion of physical activity, reduction in academic pressures, promotion of dietary diversity, reduction of sedentary time, and engagement in formal sporting activities should be elements of policies to promote healthy weight status and prevent obesity in school students, which will also support physical fitness. FUNDING: National Natural Science Foundation, Humanities and Social Sciences Planning Fund Project, China Scholarship Council, and Innovation Fund for Outstanding Doctoral Candidates of Peking University Health Science Center.