Secular trend and projection of overweight and obesity among Chinese children and adolescents aged 7-18 years from 1985 to 2019: Rural areas are becoming the focus of investment.

BACKGROUND: The urban-rural disparities in overweight and obesity among children and adolescents are narrowing, and there is a need for long-term and updated data to explain this inequality, understand the underlying mechanisms, and identify priority groups for interventions. METHODS: We analyzed data from seven rounds of the Chinese National Survey on Students Constitution and Health (CNSSCH) conducted from 1985 to 2019, focusing on school-age children and adolescents aged 7-18 years. Joinpoint regression was used to identify inflection points (indicating a change in the trend) in the prevalence of overweight and obesity during the study period, stratified by urban/rural areas and sex. Annual percent change (APC), average annual percent change (AAPC), and 95% confidence interval (CI) were used to describe changes in the prevalence of overweight and obesity. Polynomial regression models were used to predict the prevalence of overweight and obesity among children and adolescents in 2025 and 2030, considering urban/rural areas, sex, and age groups. RESULTS: The prevalence of overweight and obesity in urban boys and girls showed an inflection point of 2000, with AAPC values of 10.09% (95% CI: 7.33-12.92%, t = 7.414, P <0.001) and 8.67% (95% CI: 6.10-11.30%, t = 6.809, P <0.001), respectively. The APC for urban boys decreased from 18.31% (95% CI: 4.72-33.67%, t = 5.926, P = 0.027) to 4.01% (95% CI: 1.33-6.75%, t = 6.486, P = 0.023), while the APC for urban girls decreased from 13.88% (95% CI: 1.82-27.38%, t = 4.994, P = 0.038) to 4.72% (95% CI: 1.43-8.12%, t = 6.215, P = 0.025). However, no inflection points were observed in the best-fit models for rural boys and girls during the period 1985-2019. The prevalence of overweight and obesity for both urban and rural boys is expected to converge at 35.76% by approximately 2027. A similar pattern is observed for urban and rural girls, with a prevalence of overweight and obesity reaching 20.86% in 2025. CONCLUSIONS: The prevalence of overweight and obesity among Chinese children and adolescents has been steadily increasing from 1985 to 2019. A complete reversal in urban-rural prevalence is expected by 2027, with a higher prevalence of overweight and obesity in rural areas. Urgent action is needed to address health inequities and increase investments, particularly policies targeting rural children and adolescents.

The long-term changing patterns of suicide mortality in China from 1987 to 2020: continuing urban-rural disparity.

BACKGROUND: Over the past three decades, China has experienced significant changes in urban-rural, gender, and age-specific suicide mortality patterns. This study aimed to investigate the long-term trends in suicide mortality in China from 1987 to 2020. METHODS: Suicide mortality data were obtained from China's National Health Commission. Joinpoint regression analysis was used to examine changes in trends and age-period-cohort modeling to estimate age, period, and cohort effects on suicide mortality from 1987 to 2020. Net drift, local drift, longitudinal age curves, and period relative risks were also calculated. RESULTS: Crude and age-standardized suicide mortality in China showed continuing downward trends from 1987 to 2020, with a more pronounced decrease in rural areas (net drift = -7.07%, p<0.01) compared to urban areas (net drift = -3.41%, p<0.01). The decline curve of urban areas could be divided into three substages. Period and cohort effects were more prominent in rural areas. Suicide risk was highest among individuals aged 20-24 and gradually increased after age 60. Females, particularly those of childbearing age, had higher suicide risk than males, with a reversal observed after age 50. This gender reversal showed distinct patterns in urban and rural areas, with a widening gap in urban areas and a relatively stable gap in rural areas. CONCLUSIONS: Suicide mortality in China has consistently declined over the past three decades. However, disparities in age, gender, and urban-rural settings persist, with new patterns emerging. Targeted suicide prevention programs are urgently needed for high-risk groups, including females of childbearing age and the elderly, and to address the slower decrease and reversing urban-rural gender trends.

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.

Associations of school physical activity environment with comorbid obesity and myopia in children and adolescents: Findings from a Chinese national follow-up study.

BACKGROUND: Overweight and obesity (OWOB) and myopia have become two of the most important issues affecting the health of children and adolescents worldwide. Despite the recognition that the school physical activity (PA) environment is a critical factor for preventing and controlling overweight, obesity (OWOB), and myopia in children and adolescents, research on OWOB and myopia as a comorbidity remains unexplored, with evidence for effective strategies still being inconclusive. Hence, this study aimed to assess the prevalence and progression of comorbid OWOB/myopia and each condition alone, and to explore the association with school PA environment. METHODS: A total of 9814 children and adolescents aged 6-18 years were included from the Chinese National Survey on Students' Constitution and Health follow-up survey conducted from November 2019 to November 2020 in China. Anthropometric measurements, unaided distance vision acuity and non-cycloplegic refraction data were collected to assess OWOB and myopia, while eight indicators from questionnaires for children and adolescents aged 9-18 years were investigated to assess school PA environment. We calculated the one-year incidence and progression rates of comorbid OWOB/myopia, OWOB alone, and myopia alone. Mixed effect logistic regression was evaluated the association between school PA environment and incidence and progression of comorbid OWOB/myopia, OWOB, and myopia. RESULTS: The prevalence of comorbid OWOB/myopia increased from 11.1% in 2019 to 17.9% in 2020, and the incidence of comorbid OWOB/myopia was 10.9%. Children and adolescents experiencing an unfavorable school PA environment had a higher risk of the incidence of comorbid OWOB/myopia compared to a favorable school environment (OR = 1.85, 95% CI: 1.42-2.42). Similar findings were seen in the incidence of obesity (OR = 1.86, 95% CI: 1.26-2.75). Children and adolescents in an unfavorable school PA environment had a higher risk of myopia progression (OR = 1.29, 95% CI: 1.01-1.65). CONCLUSIONS: Obesity and myopia and their comorbidity have been serious among children and adolescents in China. A favorable school PA environment might mitigate the risk of comorbid OWOB/myopia, OWOB, and myopia progression.

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.

Socioeconomic, Health Services, and Multimorbidity Disparities in Chinese Older Adults.

INTRODUCTION: As one of the world's most populous countries, China persistently confronts a significant multimorbidity burden. This study aimed to elucidate the multimorbidity burden experienced by Chinese older adults, explore its interplay with socioeconomic disparity, and investigate potential correlations between these provincial disparities and health services availability. METHODS: The fourth wave of China's national Urban and Rural Elderly Population study, conducted in 2015, was used to construct a multimorbidity index and elucidate the geographic differences in the multimorbidity burden. Incorporating macrolevel indicators about socioeconomic and health services availability, quantile regression and Spearman correlation analyses were employed to investigate the relationship between multimorbidity and socioeconomic disparities and examine the potential linkages between these provincial disparities and health services availability. Analyses were performed in 2023. RESULTS: The final analysis included a total of 213,857 older adults. At the provincial level, significant geographic disparities in multimorbidity burden were identified. After adjusting for individual social determinants of health, an independent association was found between the human development index and a higher multimorbidity index (coefficient= -0.22; 95% CI= -0.24, -0.19). Furthermore, a significant positive correlation emerged between human development index and both population and geographic densities of health services availability. Notably, geographic density displayed greater inequality (Gini coefficients=0.45-0.48) than population density (Gini coefficients=0.03-0.10). CONCLUSIONS: This study demonstrates that multimorbidity burden in China is linked to provincial socioeconomic disparities and that inequality in health services availability may account for this, which would advocate for a need to reduce disparities in health services availability.

Urban-Rural Disparity in Mortality Patterns of Respiratory Diseases Among Older Adults - China, 1987-2021.

What is already known about this topic?: Respiratory diseases (RDs) are the primary cause of death in older adults in China. However, there is limited evidence regarding the disparity in mortality rates of RDs between urban and rural areas among the elderly population. What is added by this report?: The age-standardized mortality rate (ASMR) due to RDs in the elderly population in both urban and rural areas of China has shown a consistent decrease. This trend is observed in both males and females. However, there was no significant change in the average annual percentage of ASMR for pneumonia among the urban elderly population and rural elderly men throughout the study period. What are the implications for public health practice?: Efforts should be made in China to reduce mortality from chronic lower respiratory disease and pneumonia among the elderly, particularly in urban populations.

Age-Period-Cohort Analysis on Long-Term Mortality Trend of Genitourinary Diseases - China, 1987-2021.

What is already known about this topic?: There has been a lack of attention to genitourinary diseases for an extended period, resulting in limited research on the mortality trends of genitourinary diseases in China. What is added by this report?: This study examines the long-term trend of genitourinary diseases' mortality across Chinese individuals of all genders and in various urban and rural regions. Additionally, it investigates the impact of age-period-cohort effects on this trend. What are the implications for public health practice?: It is imperative to address genitourinary diseases, particularly among vulnerable populations such as rural older men. Policymakers should prioritize these individuals by providing necessary policy interventions and healthcare support.

Long-term Trends in Healthy and Unhealthy Life Expectancy Among Adults Aged 60 - A Global Perspective, 1990-2019.

What is already known about this topic?: Traditionally, life expectancy has served as a pivotal measure for assessing population health. However, there is an increasing focus on distinguishing healthy years of life from those characterized by illness, particularly among the elderly population. What is added by this report?: This study conducts an exhaustive global analysis of the trends in healthy and unhealthy life expectancy among adults aged 60 and over from 1990 to 2019. These trends are further correlated with socio-demographic indicators and health services metrics. What are the implications for public health practice?: Comprehending the dynamics between healthy and unhealthy life years can equip policymakers with the necessary insights to prioritize interventions. These interventions can thereby secure both quality and longevity of life for the increasingly aging population.

Urban-rural disparities in the prevalence and trends of depressive symptoms among Chinese elderly and their associated factors.

BACKGROUND: This study aimed to examine urban-rural disparities in the prevalence and trends of depressive symptoms (DS) among Chinese elderly and associated factors. METHODS: A total of 8025, 7808, and 4887 respondents aged 60 years and above were selected from the China Family Panel Studies (CFPS) in 2016, 2018, and 2020, respectively. DS was assessed using a short version of Center for Epidemiologic Studies Depression Scale (CES-D). Twenty-two associated factors from six categories were included in random forest (RF) models. All urban-rural comparisons were conducted based on good model performance. RESULTS: The DS prevalence among all rural elderly was significantly higher than corresponding urban elderly. This disparity continued to widen among younger elderly, while it continued to narrow among older elderly. The top 10 common leading factors were sleep quality, self-rated health, life satisfaction, memory ability, child relationship, IADL disability, marital status, educational level, and gender. Urban-rural disparities in sleep quality, interpersonal trust, and child relationship continued to widen, while disparities in multimorbidity, hospitalization status, and frequency of family dinner continued to narrow. LIMITATION: This study may exist recall bias and lacks causal explanation. CONCLUSIONS: Significant and continuing disparities in the DS prevalence were observed between urban and rural elderly in China, showing opposite trends in younger and older elderly. The top 10 leading associated factors for DS were nearly consistent across urban and rural elderly, with sleep quality having strongest contribution. Urban-rural disparities in associated factors also showed different trends. This study provides a reference for mental health promotion among Chinese elderly.

Activities of Daily Living-Related Functional Impairment Among Population Aged 65 and Older - China, 2011-2050.

What is already known about this topic?: The elevated prevalence of functional impairment among elderly individuals in China contributes to an increased burden of care. What is added by this report?: This report presents a comprehensive evaluation of trends in functional impairment related to activities of daily living (ADL) among the elderly population in China. Furthermore, it offers insights for future projections of these trends in this demographic group. What are the implications for public health practice?: Addressing the care needs and functional impairment issues among the aging population in China necessitates interdepartmental collaboration.

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.

Changing Patterns of Heart Disease Mortality in Rural and Urban Areas - China, 1987-2021.

What is already known about this topic?: The burden of heart disease is increasing rapidly due to the aging population and changing lifestyles in China. What is added by this report?: This study investigated the evolution of mortality rates due to heart disease in urban and rural areas of China over the past 35 years, and identified the age-period-cohort effects on mortality changes. What are the implications for public health practice?: Healthcare providers should prioritize attention to heart disease among older males living in rural areas.

Association between multimorbidity and memory-related diseases among middle-aged and older adults: Evidence from the China Health and Retirement Longitudinal Study.

Objectives: This study aimed to examine the cross-sectional and longitudinal association between multimorbidity and memory-related diseases (MDs) among Chinese middle-aged and older adults. Methods: This study included 8,338 subjects who participated in the China Health and Retirement Longitudinal Study (CHARLS). Logistic regression and Cox proportional hazards regression models were used to explore the association and effect of multimorbidity on MDs. Results: The overall prevalence of MDs was 2.52%, and the mean multimorbidity number was 1.87. In a cross-sectional analysis, compared with the no multimorbidity group, groups of multimorbidity with four or more non-communicable diseases (NCDs) were more likely to have MDs (OR: 6.49, 95%CI: 4.35-9.68). Within 2.7 years of follow-up, 82 cases of MDs (1.12%) were reported, and participants with multimorbidity were more likely to have new-onset MDs than participants without multimorbidity (HR: 2.93, 95%CI: 1.74-4.96). Conclusion: Multimorbidity is associated with MDs among Chinese middle-aged and older adults. This relationship gradually strengthens with the severity of multimorbidity, which indicates that early prevention for people with multimorbidity may reduce the risk of MDs.

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.

Association between early life exposure to the great famine and possible sarcopenia in older Chinese adults: a national cross-sectional study.

OBJECTIVES: We used data from the China Health and Retirement Longitudinal Study (CHARLS) to investigate how an early life famine exposure affected possible sarcopenia (PS) and to explore the extent to which a sex difference exists in the association among older Chinese adults, as well as whether risk factors modify the association. DESIGN: Cross-sectional study. SETTING: 28 provinces of China. PARTICIPANTS: Considering that the Great Chinese Famine lasted from the spring of 1959 to the fall of 1961, 3557 participants were selected and categorised into four subgroups based on their date of birth: unexposed group (1 October 1962 to 30 September 1964), fetal exposed group (1 October 1959 to 30 September 1961), infant exposed group (1 January 1958 to 31 December 1958) and preschool exposed group (1 January 1956 to 31 December 1957). OUTCOME MEASURE: PS was defined as having low muscle strength or low physical performance. METHODS: We used multivariable logistic models to analyse the association between early life famine exposure and the risk of PS in elderly life. RESULTS: The prevalences of PS among individuals in the unexposed, fetal, infant and preschool exposed groups were 15.1%, 14.4%, 23.6% and 21.9%, respectively. Compared with the unexposed group, the infant (OR: 1.55; 95% CI 1.17 to 2.05) and preschool exposed (OR: 1.46; 95% CI 1.17 to 1.82) groups exhibited significantly higher risks of PS. In men, the infant (OR: 2.15; 95% CI 1.40 to 3.31) and preschool exposed (OR: 1.78; 95% CI 1.23 to 2.57) groups were more likely to have PS, but no significant increase was seen in women. In both sexes, prevalence of PS was unrelated to early life famine exposure in the urban, underweight and normal weight subgroups. CONCLUSIONS: Early life exposure to the Great Chinese Famine was associated with a higher risk of PS in older adults. Keeping normal nutritional status in elderly life might help avoid the risk of PS, whatever the effect of early famine exposure.

Artificial Light-at-Night Exposure and Overweight and Obesity across GDP Levels among Chinese Children and Adolescents.

BACKGROUND: Evidence in adults suggests that exposure to artificial light-at-night (ALAN) leads to obesity. However, little is known about whether this effect exists in children and adolescents. We aimed to investigate whether ALAN exposure was associated with overweight and obesity in school-aged children and adolescents and whether this association varied with socioeconomic status. METHODS: Data on the height and weight of 129,500 children and adolescents aged 10-18 years from 72 cities were extracted from the 2014 Chinese National Survey on Students' Constitution and Health (CNSSCH). The ALAN area percentage and average ALAN intensity were calculated using the Visible/Infrared Imager/Radiometer Suite. The subjects were separated into three categories based on the cities' gross domestic product per capita (GDPPC). A mixed-effect logistic regression model and generalized additive model (GAM) were utilized to evaluate the association between ALAN exposure and overweight and obesity in children and adolescents stratified by municipal GDPPC. RESULTS: Both ALAN area (OR = 1.194, 95% CI: 1.175-1.212) and ALAN intensity (OR = 1.019, 95% CI: 1.017-1.020) were positively associated with overweight and obesity in children and adolescents, and the associations remained robust after adjusting for covariates. ORs for overweight and obesity and ALAN area decreased as GDPPC level increased (first tertile: OR = 1.457, 95% CI: 1.335-1.590; second tertile: OR = 1.350, 95% CI: 1.245-1.464; third tertile: OR = 1.100, 95% CI: 1.081-1.119). Similar results were observed for ALAN intensity. In the GAM models, thresholds existed in almost all these spline trends, indicating that ALAN might have a nonlinear association with overweight and obesity. CONCLUSIONS: ALAN contributed to the development of overweight and obesity in children and adolescents and this effect differed with GDPPC. Future longitudinal studies should confirm the causal relationship between ALAN and obesity. Moreover, reducing unnecessary exposure to artificial light at night may have beneficial implications for controlling childhood and adolescent obesity, particularly in low-income areas.

Changing Patterns in Cancer Mortality from 1987 to 2020 in China.

BACKGROUND: China has the highest number of new cancer cases and deaths worldwide, posing huge health and economic burdens to society and affected families. This study comprehensively analyzed secular trends of national cancer mortality statistics to inform future prevention and intervention programs in China. METHODS: The annual estimate of overall cancer mortality and its major subtypes were derived from the National Health Commission (NHC). Joinpoint analysis was used to detect changes in trends, and we used age-period-cohort modeling to estimate cohort and period effects in Cancers between 1987 and 2020. Net drift (overall annual percentage change), local drift (annual percentage change in each age group), longitudinal age curves (expected longitudinal age-specific rate), and period (cohort) relative risks were calculated. RESULTS: The age-standardized cancer mortality in urban China has shown a steady downward trend but has not decreased significantly in rural areas. Almost all cancer deaths in urban areas have shown a downward trend, except for colorectal cancer in men. Decreasing mortality from cancers in rural of the stomach, esophagus, liver, leukemia, and nasopharynx was observed, while lung, colorectal cancer female breast, and cervical cancer mortality increased. Birth cohort risks peaked in the cohorts born around 1920-1930 and tended to decline in successive cohorts for most cancers except for leukemia, lung cancer in rural, and breast and cervical cancer in females, whose relative risks were rising in the very recent cohorts. In addition, mortality rates for almost all types of cancer in older Chinese show an upward trend. CONCLUSIONS: Although the age-standardized overall cancer mortality rate has declined, and the urban-rural gap narrowed, the absolute cancer cases kept increasing due to the growing elderly population in China. The rising mortality related to lung, colorectal, female breast, and cervical cancer should receive higher priority in managing cancer burden and calls for targeted public health actions to reverse the trend.

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.