Objective: To investigate the normal urinary manganese value in healthy adults in Guangxi, China and its distribution characteristics. Methods: From 2015 to 2016, stratified random sampling based on age and sex was performed to select 1533 healthy adults aged 18-60 years in Nanning,Liuzhou,Guilin,Hezhou,Wuzhou,Yulin,Guigang,Beihai,Qinzhou,Laibin,Hechi Nandan,Bose Jingxi,Chongzuo Daxin,and Fangchenggang.All of them had no history of occupational manganese exposure or acute or chronic liver/renal diseases and had lived in the local area for more than one year. A total of 1417 urine samples with normal specific gravity and complete data were obtained, and graphite furnace atomic absorption spectrometry was used to measure urinary manganese.The distribution characteristics of urinary manganese level were analyzed among adults with different ages,sexes,or presence or absence of smoking habits or among those who lived or did not live in the mining area. Results: The geometric mean of urinary manganese among healthy adults in Guangxi was 0.52 μg/L,and the upper limit of normal was 5.68μg/L. There was no significant difference in urinary manganese level between the healthy adults with different ages, sexes,or presence or absence of smoking habits (P>0.05).The healthy adults who lived in the mining area of nonferrous metal mines had a significantly higher geometric mean of urinary manganese than those who did not live in such areas(1.65μg/Lvs0.34μg/L,P<0.01). Conclusion The upper limit of normal of urinary manganese is 5.68 μg/L among healthy adults in Guangxi,and the healthy adults who live in the mining area of manganese mine or nonferrous metal mines have a significantly higher urinary manganese level than those who do not live in such areas.

Objective: To investigate the upper limit of the normal value of arsenic in healthy adult population in different areas of Guangxi. Methods: From 2015 to 2016, 1533 subjects from 14 counties and cities in Guangxi were collected by age, gender, stratified random sampling and questionnaire survey. 1417 urine samples with satisfactory urine quality and complete information were collected.The content of arsenic in urine was determined by atomic fluorescence spectrometry. Results: The upper limit of normal arsenic in healthy adults in guangxi was 0.053 mg/L. Male urinary arsenicP₅₀(0.011mg/L)was higher than that of the female(0.008mg/L), the difference was statistically significant(Z=5.352,P<0.01). Smoking urinary arsenicP₅₀(0.012mg/L) was higher than that of nonsmokers(0.009mg/L), the difference was statistically significant(Z=3.404,P<0.01). GroupP₅0 urine arsenic in coastal areas(0.012mg/L) the crowd was higher than that in non coastal areas(0.009mg/L), the difference was statistically significant(Z=-7.522,P<0.01). Conclusion The upper limit of normal arsenic in healthy adults in Guangxi area is 0.053mg/L,and there are differences in the levels of arsenic in healthy adults, such as different genders and regions.

Abstract The health of children and adolescents is not only related to the growth and wellbeing of individuals, but also to the construction and development of countries. This study reviewed policies that were issued by the central government since the founding of New China which focused on the prevention and treatment of common diseases among school-age children and adolescents. The results revealed that, since the founding of New China, policies for the prevention and control of common diseases among school-age children and adolescents increased in number, and they began to focus on specific rather than general health problems. A gradual emphasis was placed on the specific implementation of prevention and control measures, rather than on guiding principles. Increasingly more attention has been paid to the prevention and treatment of common diseases among school-age children and adolescents.

Objective: To analyze the association between the occurrence of menarche and the exposure to artificial light at night (ALAN) in female Han nationality girls aged 9-18 in China, so as to provide a reference for the research on the disturbance mechanism of ALAN on puberty, as well as provide a scientific evidence for controlling ALAN and making public sanitary policy. Methods: A total of 74 483 Han girls aged 9-18 with complete records of menarche, height, and weight were included in the 2014 Chinese National Surveys on Students Constitution and Health. Pearson correlation was used to explore the correlation between the incidence of menarche and the exposure to artificial light at night in 11-year-old Han girls, and the third quantiles of the area covered by outdoor night lights (0.16, 0.60) and the third quantiles of the average night light intensity [0.97, 5.91 nw/(sr ·cm) 2] were used respectively to divide the study subjects into 3 groups, and the multifactor Logistic regression model was used to analyze the effect of artificial light at night exposure on menarche. Results: In 2014, the median age of menarche of Chinese Han girls was 12.18 years old, and the incidence of menarche in the 11-year-old group was 26.31%. After controlling for body mass index, local population and the logarithmic values of per capita GDP, the incidence of menarche of 11-year-old Han girls was positively correlated with the local outdoor average night light coverage area ratio and the night average light intensity logarithmic adjustment value( r =0.29, 0.30, P <0.05).The higher the local outdoor night light coverage area ratio ( OR =1.28, 1.52) and the average night light intensity ( OR =1.47, 1.58), the higher the incidence of menarche in 11-year-old Han girls( P <0.05). Conclusion There is a positive correlation between artificial light at night exposure and the menarche rate of 11-year-old Han girls. Research on artificial light at night exposure may provide scientific evidence on puberty onset and its effects on population health.

Objective: To construct core information about physical activities of Chinese students aged 7-18 years, so as to provide a reference for impoving the level of adolescents physical activities. Methods: Canadian 24 Hour Movement Guidelines for Children and Youth was used as a framework, the preliminary core recommendations on physical activity for Chinese students aged 7-18 years were developed based on qualitative research. Recommendations covered three scales, including physical activity, sedentary behaviour and sleep. Physical activity included four subscales of frequency, intensity, duration and type, while sedentary behaviour and sleep only included one subscale. Three rounds of consultation were conducted using Delphi method. In the second round of consultation, the results of 2014 Chinese National Surveys on Students Constitution and Health were presented to experts for reference. In the third round of consultation, experts need to rank the importance of seven items of physical fitness under the physical activity type subscale by age group through analytic hierarchy process. Results: Totally 25, 25, and 18 experts were consulted in three rounds respectively. The questionnaire response rates in 3 rounds were 100.0%, 100.0%, and 94.4%, respectively. The authority coefficients were 0.92, 0.93, and 0.91. The harmony coefficients were 0.63( χ 2=237.10, P <0.01), 0.63( χ 2= 242.60 , P <0.01), and 0.76( χ 2=97.05, P <0.01). It was recommended that students aged 7 to 18 years in China should do moderate to vigorous physical activity for a cumulative total of at least 60 minutes per day, and most of the 60 minutes or more per day should be either moderate or vigorous intensity aerobic physical activity. Of the daily physical activity, students should conduct vigorous intensity aerobic physical activity, muscle strengthening and bone strengthening physical activity on at least 3 days a week. At least 2 hours of daytime outdoor activity was recommended for primary school students and 1 hour for secondary school students. 7-12 year old students should do more physical activities that enhance flexibility, coordination and agility, while 13-18 year old students should do more physical activities that enhance strength, endurance and speed. Sedentary behaviour included one subscale, where students should reduce sedentary behaviour, break up long periods of sitting as often as possible, and limit recreational screen time and online study time. Sleep included one subscale of duration.Students should get sufficient and uninterrupted sleep per night. Conclusion The development of core recommendations on physical activity for Chinese students aged 7 to 18 might help improve physical activity levels and promote health of children and adolescents.

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.

Objective:To establish a method for the simultaneous determination of 22 elements, including beryllium, vanadium, chromium, manganese, iron, calcium, magnesium, barium, cobalt, cadmium, copper, zinc, arsenic, selenium, titanium, strontium, nickel, molybdenum, tin, antimony, thallium and lead, in whole blood by inductively coupled plasma mass spectrometry (ICP-MS) .Methods:In September 2023, the analysis conditions were determined by optimizing the detection mode of the instrument, the pretreatment mode and the dilution factor of the samples, etc. Whole blood samples were diluted with a mixture of 0.1% nitric acid and 0.05% triton X-100, and centrifuged at 2000 r/min by high-speed centrifuge for 2 min. The supernatant was taken into inductively coupled plasma mass spectrometer to determine the content of 22 elements, and the detection limit and precision of the method were analyzed.Results:The 22 elements had a good linear relationship in their respective measurement ranges ( r=0.9991-0.9999), the detection limit ranged from 0.003 μg/L to 0.012 mg/L. The intra-batch precision ranged from 0.5% to 7.2%, the inter-batch precision ranged from 0.4% to 9.4%, and the average recoveries ranged from 80.6% to 114.9%. Conclusion:ICP-MS method has a good effect on the determination of 22 elements in whole blood. The method is fast and simple, and can be used for clinical detection of multiple elements in whole blood.

Objective:To establish a method for the simultaneous determination of 22 elements, including beryllium, vanadium, chromium, manganese, iron, calcium, magnesium, barium, cobalt, cadmium, copper, zinc, arsenic, selenium, titanium, strontium, nickel, molybdenum, tin, antimony, thallium and lead, in whole blood by inductively coupled plasma mass spectrometry (ICP-MS) .Methods:In September 2023, the analysis conditions were determined by optimizing the detection mode of the instrument, the pretreatment mode and the dilution factor of the samples, etc. Whole blood samples were diluted with a mixture of 0.1% nitric acid and 0.05% triton X-100, and centrifuged at 2000 r/min by high-speed centrifuge for 2 min. The supernatant was taken into inductively coupled plasma mass spectrometer to determine the content of 22 elements, and the detection limit and precision of the method were analyzed.Results:The 22 elements had a good linear relationship in their respective measurement ranges ( r=0.9991-0.9999), the detection limit ranged from 0.003 μg/L to 0.012 mg/L. The intra-batch precision ranged from 0.5% to 7.2%, the inter-batch precision ranged from 0.4% to 9.4%, and the average recoveries ranged from 80.6% to 114.9%. Conclusion:ICP-MS method has a good effect on the determination of 22 elements in whole blood. The method is fast and simple, and can be used for clinical detection of multiple elements in whole blood.

Objective:We aimed to assess the effects of outdoor time in preventing incident myopia among primary school students and evaluate its differences among different grades to provide evidence for policy formulation related to myopia prevention.Methods:This study is a cohort study. We investigated 6 046 grade 1 to 5 students in 9 provinces, Jiangsu, Shanghai, Fujian, Shanxi, Henan, Hunan, Gansu, Chongqing, and Guangxi. In 2019, we measured their myopia on site. In 2020, we did a follow-up visit on those students to detect the myopia incidence rate. Information regarding outdoor time and myopia-related behaviors were obtained from a questionnaire within one week of visual acuity measurement in 2020. The chi-square test and Cochran-Armitage trend test compared the differences between groups. The Cox proportional hazards risk model was used to test the relationship between outdoor time and myopia.Results:In 2020, the overall myopia incidence rate of grade 1 to 5 students in the baseline was 27.5%; while 23.0% in grades 1 and 2 students and 31.7% in grades 3 to 5 students, respectively. After controlling for covariates, for students in grade 1 to 2, those with ≥1 hour of outdoor time per day were at 0.76 (95% CI: 0.62-0.93, P=0.008) times risk of being myopia than that of students with <1 hour of outdoor time per day; while for students in grades 3 to 5, an average of ≥3 hours of outdoor time per day was required to have a significant protective effect on myopia. The students with ≥3 hours of outdoor time per day were less likely to be myopia ( OR=0.75, 95% CI: 0.61-0.93, P=0.007) than those students with <3 hours of outdoor time per day. Conclusions:For grade 1 and 2 students, 1 hour of outdoor time per day could reduce the incidence of myopia, whereas for grade 3 to 5 students, 3 hours of outdoor time per day could effectively reduce the incidence of myopia. Therefore, the recommendations for outdoor time as myopia prevention should be different for different grades. The higher the grade is, the more outdoor time should be spent to reduce myopia incidence. Moreover, other factors that affect myopia's incidence should be also paid attention to, and a comprehensive approach should be adopted to prevent and control the incidence of myopia.

Objective:To describe the prevalence of psychological distress and to analyze its influencing factors among Chinese children and adolescents aged 9-18 years in 2019.Methods:Data was from the 2019 Chinese National Survey on Students' Constitution and Health, and 148 892 children and adolescents were included. Psychological distress was measured using the Kessler Psychological Distress Scale (K10): scores ≤19 were defined as no psychological distress, scores between 20-24 were defined as mild psychological distress, scores between 25-29 were defined as moderate psychological distress, and scores ≥30 were defined as severe psychological distress (moderate to severe psychological distress were defined as high psychological distress). The ANOVA, t test, and χ2 test were used to compare the differences in K10 scores and high psychological distress rates among children and adolescents with different characteristics. The ANOVA and trend χ2 test were used to analyze the trends. Modified-Poisson regression models were used to determine influencing factors of high psychological distress. Results:The K10 scores for Chinese children and adolescents aged 9-18 years in 2019 was 21.5±9.2, and their rate of high psychological distress was 31.6%. The rates of high psychological distress among children and adolescents aged 9-12, 13-15, and 16-18 years were 22.3%, 35.9%, and 38.8%. K10 scores and rates of high psychological distress showed an increasing trend as age increased (trends test all P<0.001). K10 scores and rates of high psychological distress were higher among children and adolescents who were older, female, rural, in areas with medium to low GDP per capita level, and with lower parental education (all P<0.001). Multifactorial modified-Poisson regression analysis showed that children and adolescents aged 13-15 years, 16-18 years, female, rural, and in areas with low to moderate GDP per capita level were at higher risk of high psychological distress (all P<0.05), with a OR (95% CI) of 1.55 (1.52-1.58), 1.66 (1.63-1.69), 1.07 (1.05-1.09), 1.02 (1.01-1.04), 1.10 (1.07-1.12). Children and adolescents in areas with medium to high GDP per capita level, whose father had a secondary or high school degree, whose father had a college degree or above, whose mother had a secondary or high school degree, and whose mother had a college degree or above were at lower risk of high psychological distress (all P<0.05), with a OR (95% CI) of 0.96 (0.94-0.98), 0.92 (0.90-0.93), 0.84 (0.82-0.86), 0.95 (0.93-0.97), 0.86 (0.83-0.88). Conclusions:The prevalence of psychological distress was high among Chinese children and adolescents aged 9-18 years in 2019, which is a vital problem. Mental health interventions need to be implemented among children and adolescents that were older, girls, rural, live in areas with lower economic levels, and whose parents have a lower education level.