Prevalence of physical fitness in Chinese school-aged children： Findings from the 2016 Physical Activity and Fitness in China -The Youth Study

Purpose： This study was to present the 2016 prevalence estimates of Chinese school-aged children meeting physical fitness standards and to examine differences by sex and residence locales in children who did not meet fitness standards. Methods： We conducted cross-sectional analyses of 171,991 children and adolescents （boy： 50.0%, Grades 1-12） who participated in the 2016 Physical Activity and Fitness in China--The Youth Study. The main outcomes were fitness measures, assessed by the 2014 revised Chinese National Student Physical Fitness Standard （CNSPFS）, covering areas of aerobic capacity, upper body strength, flexibility, body mass index, abdominal strength, and trunk strength. Children＇s overall physical fitness performance was categorized, per CNSPFS standards, as excellent, good, pass, or no pass. Data on the prevalence of physical fitness categories and not meeting fitness standards （i.e., among children who received a ＂no pass＂ mark） were analyzed, through logistic regression, by sex （boy, girl） and residence locales （urban, rural） across 3 school grades （primary, junior middle, and junior high）. Results： In 2016, 5.95% of Chinese children and adolescents achieved an ＂excellent＂ mark, 25.80% received a ＂good＂ rating, 59.90% received a ＂pass＂, and 8.35% received a ＂no pass＂. Overall, boys were more likely to not pass the fitness standards compared with girls （adjusted odds ratio （aOR） = 1.710; 95% confidence interval （CI）： 1.708-1.712） and children living in urban areas were more likely to not pass the standards than those living in rural areas （aOR = 1.298; 95%CI： 1.296-1.299）. Consistent patterns of not meeting fitness standards were also found by sex and residence locales across all 3 school grades. Conclusion： In the Chinese school-aged population, about 3 in 10 children achieved an ＂excellent＂ or ＂good＂ fitness standard in 2016, and about 8% of this population did not meet CNSPFS standards. Children living in urban areas were more likely to not meet minimum fitness performance levels, and boys in school were more likely to not meet minimum fitness performance levels than girls. 2017 Production and hosting by Elsevier B.V. on behalf of Shanghai University of Sport. This is an open access article under the CC BY-NC-ND license （http：//creativecommons.org/licenses/by-nc-nd/4.0/）.

Physical activity among Chinese school-aged children:National prevalence estimates from the 2016 Physical Activity and Fitness in China The Youth Study

Purpose: This study was to present national estimates of participating in moderate-to-vigorous physical activity(MVPA) and adherence to the recommendations of 60 min/day of MVPA among Chinese school-aged children and to assess demographic differences in MVPA.Methods: Cross-sectional analyses of data from the 2016 Physical Activity and Fitness in China—The Youth Study. Participants were 90,712 primary, junior middle, and junior high school children(boy: 47%; girl: 53%), recruited from 1204 rural and urban schools across 32 administrative provinces and regions in the Mainland of China. Main outcomes were(a) average MVPA minutes per day in the previous 7 days by self-reports and(b) percentage meeting MVPA recommendations.Results: Average MVPA time was 45.4 min/day, with boys having more MVPA(47.2 min/day) than girls(43.7 min/day) overall and across the 3 school grade categories. About 30% of participants met MVPA recommendations, with a higher percentage of boys(32%) than girls(28%) overall and across the 3 grades categories. Urban school children outperformed rural children in terms of MVPA time. Overall, boys were more likely to meet MVPA recommendations(adjusted odds ratio(a OR) = 1.19, 95% confidence interval(CI): 1.16–1.22) compared with girls; children in higher grades(junior middle(a OR = 0.92, 95%CI: 0.87–0.98) and junior high(a OR = 0.59, 95%CI: 0.53–0.66)) were less likely to meet recommendations compared with primary school children. The odds of meeting recommendations did not differ between urban and rural children(p = 0.07),but urban boys were found to be more likely to meet recommendations compared with rural boys(a OR = 1.14, 95%CI: 1.06–1.19).Conclusion: Overall, the average MVPA minutes per day among Chinese school-aged children is low, and less than one-third of them meet MVPA recommendations. These results were most evident among junior middle and junior high school children and those living rural areas.

Prevalence and correlates of meeting the muscle-strengthening exercise recommendations among Chinese children and adolescents:Results from 2019 Physical Activity and Fitness in China—The Youth Study

Purpose This study aimed to describe the national prevalence of Chinese children and adolescents who met the World Health Organization muscle-strengthening exercise(MSE)recommendations and identify correlates of meeting the MSE recommendations.Methods Cross-sectional data from the 2019 Physical Activity and Fitness in China—The Youth Study,a nationally representative sample of Chinese children and adolescents(n=80,413;mean age=13.7 years;53.9%girls)and their parents,were analyzed.Children and adolescents who reported engaging≥3 days(up to 7 days)of MSE per week were classified as meeting the MSE recommendations.MSE,demographics,lifestyle behaviors(sport participation,moderate-to-vigorous physical activity,screen time,and sleep duration),exercise intention,peer and parental support,and parental MSE participation were assessed through self-reports.Logistic regression models were used to determine the correlates of meeting the MSE recommendations.The analyses were completed in 2020.Results Overall,39.3%of children and adolescents met the MSE recommendations.Girls,10th-12th graders,minorities,those from lower income households and those from families with lower parental education were less likely to meet the MSE recommendations.Children and adolescents who were proficient in≥2 sports were more likely to meet the MSE recommendations(adjusted odds ratio(aOR)=1.44,95%confidence interval(95%CI):1.26-1.65),as were those with more moderate-to-vigorous physical activity(aOR=1.57,95%CI:1.53-1.61).Additionally,children and adolescents with high exercise intention(aOR=1.60,95%CI:1.51-1.69),those whose parents met the adult MSE recommendations(aOR=1.46,95%CI:1.40-1.52),and those who received high peer(aOR=1.27,95%CI:1.20-1.34)and parental support(aOR=1.07,95%CI:1.04-1.12)were more likely to meet the MSE recommendations.Conclusion Less than two-fifths of Chinese children and adolescents met the World Health Organization MSE recommendations.The correlates identified in our study can help inform the development of school and community based strategies and policies to enhance participation in MSE and improve muscular fitness of all Chinese children and adolescents.

School and community physical activity characteristics and moderate-to-vigorous physical activity among Chinese school-aged children： A multilevel path model analysis

Purpose: The purpose of this study was to examine the association between school and community physical activity(PA) characteristics and levels of moderate-to-vigorous physical activity(MVPA) among Chinese school children.Methods: Data were obtained from the 2016 Physical Activity and Fitness in China—The Youth Study project. Participants were 80,928 school children(Grades 4–12; 39,747 boys, 41,181 girls; mean age = 13 years) and 935 physical education(PE) teachers who completed a study survey.Independent variables included both school-related factors(school-level PA support, availability of and access to PA facilities, and the duration of school PE classes) and community-related factors(the frequency of sports events, sports training opportunities, availability of sports clubs and organizations, and access to PA facilities). The dependent variable was the children's self-reported participation in MVPA. The data were analyzed,in 2017, via multilevel modeling.Results: PA support from school administrators was the only school-level factor significantly related to children's participation in MVPA.Children's perceptions of the frequency of community-sponsored sports events, availability of sports clubs and organizations, and convenient access to PA facilities were associated with a high level of MVPA participation. In regard to residency in urban and rural areas, children attending urban schools who perceived high availability of PA facilities were associated with a low level of participation in MVPA.Conclusion: School support for PA and community PA resources are associated with MVPA among Chinese school children. School PA facilities appear underutilized among urban schools as evidenced by low levels of MVPA among school children.

Associations between parental support for physical activity and moderate-to-vigorous physical activity among Chinese school children： A cross-sectional study

Purpose: The objective of this study was to examine the associations between parental support for physical activity(PA) and levels of moderate-to-vigorous physical activity(MVPA) among Chinese school children.Methods: Study participants were 81,857 school-aged children(aged 9–17 years; mean age = 13 years; 49.0% boys) and their parents or guardians who took part in the 2016 Physical Activity and Fitness in China—The Youth Study project. The independent variables included various forms of parental support for PA ascertained through a survey completed by parents or guardians. The dependent variable was the children's average MVPA in minutes per day by self-report. Structure equation modeling was used to examine the associations between parental support for PA and children's MVPA minutes.Results: The overall mean for MVPA participation time for the child participants was 48.82 ± 28.71 min/day. Significant associations between various forms of parental support and MVPA among children were found. Parental encouragement, accompanying, financial support, involvement,and role modeling for PA were positively associated with a high level of student MVPA participation. Parental PA knowledge-sharing was not associated with MVPA. The patterns of the associations were similar across sex, residence locale(i.e., urban and rural), and school grades(primary,junior middle, and junior high schools).Conclusion: Findings from this study suggest that, among Chinese school children, parental support for PA is important in promoting and facilitating children's participation in MVPA.

Promoting physical activity among Chinese youth:No time to wait

Dear Editor,In the December 2016 issue of Journal of Sport and Health Science,Dr.Barbara E.Ainsworth highlighted a global view of youth physical activity(PA)based on the results from the Global Matrix 2.0.~1Joining 38 countries on 6 continents,China,as the most populous country in the world,has for the first time presented its 2016 Report Card on 9 indicators of PA.Unfortunately,China’s inaugural Report Card shows an F rating assigned to both the overall PA level and sedentary

Determination of functional fitness age in women aged 50 and older

Background: The construction of useful and attainable indicators of fitness assessment deserves special attention in clinical practice. We aimed to construct an indicator of the functional fitness age(FFA) of women aged 50 and older by an equation using fitness outcomes and its correlation with chronological age(CA) and to analyze the external validity of our results by comparing our sample to others.Methods: Participants(n=459, age: 70.3 ± 7.9 years, mean ± SD) were evaluated using the Senior Fitness Test battery. We applied a multiple regression and a subsequent Holt's exponential smoothing to analyze the outcomes.Results: We obtained a statistically significant expression of F(6, 452) = 328.384; p < 0.0005 in which the coefficients of the equation explain81% of variability(R_(corrected)~2 = 0.813). The equation correlates fitness assessment in women aged 50 and over with regards to CA:FFA = 40.146 + 0.350 X CS(stand)-0.714 X AC(rep)-0.110 X ST(step)-0.177 X CSR(cm)-0.101 X BS(cm) + 8.835 X FUG(s) where CS means chair stand test, AC. means arm curl test, ST means 2-min step test, CSR means chair sit-and-reach test, BS means back scratch test, FUG means 8-foot up-and-go test. We compared this index with percentiles distribution from our sample and from other studies.Conclusion: We suggest the use of FFA as a valid indicator of fitness in adult and senior women as well as a useful motivational tool to undertake exercise programs.

The Association between Physical Education and Mental Health Indicators in Adolescents:A Cross-Sectional Study

Objective:To explore the associations between physical education attendance and mental health indicators.Methods:Using data from the Global Student Health Survey,the frequency of physical education attendance,suicidality-related indicators,loneliness,bullying,and anxiety were all assessed using a standardized self-reported questionnaire.Multivariable logistic regression was used to estimate the association between physical education attendance and mental health-related indicators.Results:The study included 276,169 participants from 71 coun-tries(47.3%males,aged 11–18 years old).After controlling for sex,age,food insecurity,close friends,physical activity,sedentary time,others’help,and parents’understanding,physical education attendance was not signifi-cantly associated with suicidal attempts,suicidal ideation,and anxiety.However,compared with no physical edu-cation attendance,individuals attending physical education for 1,2,as well as 5 or more days had significantly reduced odds/ratios of suicide;only 2 days of physical education attendance was associated with a lower odds ratio for suffering from loneliness.Even 1 day of physical education was associated with not being bullied by others.Conclusion:This study suggests that physical education attendance may not have an effective role in reducing mental health illnesses in children and adolescents.Future studies are encouraged to corroborate or negate our research discoveries by using better and further improved study designs.

Meeting 24-h movement guidelines: Prevalence, correlates, and the relationships with overweight and obesity among Chinese children and adolescents

Background:Meeting 24-h movement guidelines by children and adolescents has been associated with improved indicators of health,although it has been under-studied in China.Hence,this study aimed to investigate the prevalence of meeting the 24-h movement guidelines,its correlates,and its relationships with body mass index in children and adolescents in China.Methods:Cross-sectional data from the 2017 Youth Study in China of 114,072 children and adolescents(mean age=13.75 years,49.18%boys)were used.Meeting 24-h movement guidelines(60 min of daily moderate-to-vigorous physical activity,2 h of daily leisure screen time,911 h and 810 h nightly sleep duration for 613-year-olds and 1417-year-olds,respectively)and height and weight of all participants were assessed.The prevalence of meeting the 24-h movement guidelines and World Health Organization weight status categories were determined.Generalized linear models were used to determine the correlates of meeting the 24-h movement guidelines and the relationships of meeting the 24-h movement guidelines with overweight(OW)and obesity(OB).Results:Only 5.12%of Chinese children and adolescents met the 24-h movement guidelines,and 22.44%were classified as OW/OB.Older children and adolescents were less likely to meet the 24-h movement guidelines.Parental education level and family income were positively related to meeting the 24-h movement guidelines.Children and adolescents meeting the 24-h movement guidelines showed lower odds ratios for OW/OB.Compared with participants meeting the 24-h movement guidelines,boys in 4th6th grades met none of the recommendations(OR=1.22,95%CI:1.061.40),met the screen time recommendation only(OR=1.13,95%CI:1.011.28),met the nightly sleep duration recommendation only(OR=1.14,95%CI:1.031.28),and had significantly higher odds ratios for OW/OB.Similar trends were observed for girls in 4th6th grades:meeting none of the guidelines(OR=1.35,95%CI:1.141.59),meeting sleep duration guidelines only(OR=1.23,95%CI:1.081.39),and meeting moderate-to-vigorous physical activity+nightly sleep duration guidelines(OR=1.24,95%CI:1.011.54).For girls in 7th9th grades,the following trend was observed:meeting none of the guidelines(OR=1.30,95%CI:1.011.67).Conclusion:Very few Chinese children and adolescents met the 24-h movement guidelines.Age(negatively correlated),parental education level,and family income(both positively correlated)were correlates of meeting the 24-h movement guidelines.Children and adolescents meeting the 24-h movement guidelines were more likely to have lower risks for OW/OB,especially in the youngest age group(Grades 46);and girls in the middle age group(Grades 79)were also more likely to have lower risks for OW/OB.Further research studies should explore additional correlates and determinants for meeting the 24-h movement guidelines.Also,future studies should use longitudinal or interventional designs to determine the relationships between meeting the 24-h movement guidelines and OW/OB and other health indicators,while taking sex and age differences into account.

Aerobic exercise combined with huwentoxin-I mitigates chronic cerebral ischemia injury

Ca2＋ channel blockers have been shown to protect neurons from ischemia, and aerobic exercise has significant protective effects on a variety of chronic diseases. The present study injected huwentoxin-I （HWTX-I）, a spider peptide toxin that blocks Ca2＋ channels, into the caudal vein of a chronic cerebral ischemia mouse model, once every 2 days, for a total of 15 injections. During this time, a subgroup of mice was subjected to treadmill exercise for 5 weeks. Results showed amelioration of cortical injury and improved neurological function in mice with chronic cerebral ischemia in the HWTX-I ＋ aerobic exercise group. The combined effects of HWTX I and exercise were superior to HWTX-I or aerobic exercise alone. HWTX-I effectively activated the Notch signal transduction pathway in brain tissue. Aerobic exercise up-regulated synaptophysin mRNA expression. These results demonstrated that aerobic exercise, in combination with HWTX-I, effectively relieved neuronal injury induced by chronic cerebral ischemia via the Notch signaling pathway and promoting synaptic regeneration.

Quantification of intermuscular and intramuscular adipose tissue using magnetic resonance imaging after neurodegenerative disorders

Ectopic adiposity has gained considerable attention because of its tight association with metabolic and cardiovascular health in persons with spinal cord injury（SCI）. Ectopic adiposity is characterized by the storage of adipose tissue in non-subcutaneous sites. Magnetic resonance imaging（MRI） has proven to be an effective tool in quantifying ectopic adiposity and provides the opportunity to measure different adipose depots including intermuscular adipose tissue（IMAT） and intramuscular adipose tissue（Intra MAT） or intramuscular fat（IMF）. It is highly important to distinguish and clearly define these compartments, because controversy still exists on how to accurately quantify these adipose depots. Investigators have relied on separating muscle from fat pixels based on their characteristic signal intensities. A common technique is plotting a threshold histogram that clearly separates between muscle and fat peaks. The cut-offs to separate between muscle and fat peaks are still not clearly defined and different cut-offs have been identified. This review will outline and compare the Midpoint and Otsu techniques, two methods used to determine the threshold between muscle and fat pixels on T1 weighted MRI. The process of water/fat segmentation using the Dixon method will also be outlined. We are hopeful that this review will trigger more research towards accurately quantifying ectopic adiposity due to its high relevance to cardiometabolic health after SCI.

A 6-week diet and exercise intervention alters metabolic syndrome risk factors in obese Chinese children aged 11-13 years

Purpose:A randomized,controlled trial was conducted to determine whether a 6-week low calorie diet and aerobic exercise intervention could alter metabolic syndrome(MetS) risk factors in pre-pubescent obese Chinese children.Methods:The subjects were randomized into diet and exercise(DE) and control(C) groups.The DE group ingested 1600-2000 kcal/day adjusted to each participant’s basal metabolic rate,and engaged in high-volume aerobic exercise(6 days/week,twice daily,for 3 h per session) for 6 weeks.A total of 215 obese children between the ages of 11 and 13 years were recruited into the study,with 167 subjects(DE,n=95;C,n=72) completing all phases.Pre-and post-study measures included body weight,body mass index,waist circumference,body fat percentage,blood pressure and other MetS-related markers from fasting blood samples(serum cholesterol,triglycerides,insulin,and glucose).Results:Compared to controls,the DE subjects experienced significantly reduced levels for all outcome markers(p 【 0.05),except for fasting blood glucose in boys(p=0.09).Conclusion:An intensive,6-week diet and exercise intervention had favorable effects in altering MetS risk factors in obese Chinese children aged 11 to 13.

Nerve growth factor promotes in vitro proliferation of neural stem cells from tree shrews

Neural stem cells promote neuronal regeneration and repair of brain tissue after injury,but have limited resources and proliferative ability in vivo.We hypothesized that nerve growth factor would promote in vitro proliferation of neural stem cells derived from the tree shrews,a primate-like mammal that has been proposed as an alternative to primates in biomedical translational research.We cultured neural stem cells from the hippocampus of tree shrews at embryonic day 38,and added nerve growth factor（100 μg/L） to the culture medium.Neural stem cells from the hippocampus of tree shrews cultured without nerve growth factor were used as controls.After 3 days,fluorescence microscopy after DAPI and nestin staining revealed that the number of neurospheres and DAPI/nestin-positive cells was markedly greater in the nerve growth factor-treated cells than in control cells.These findings demonstrate that nerve growth factor promotes the proliferation of neural stem cells derived from tree shrews.

Relationship between biological factors and catastrophizing and clinical outcomes for female patients with knee osteoarthritis

AIM To investigate the correlations between clinical outcomes and biopsychological variables in female patients with knee osteoarthritis(OA).METHODS Seventy-seven patients with symptomatic knee OA were enrolled in this study.We investigated the age,body mass index(BMI),pain catastrophizing scale(PCS)and radiographic severity of bilateral knees using a Kellgren-Lawrence(K-L)grading system of the subjects.Subsequently,a multiple linear regression was conducted to determine which variables best correlated with main outcomes of knee OA,which were pain severity,moving capacity by measuring timed-up-and-go test and Japanese Knee Osteoarthritis Measure(JKOM).RESULTS We found that the significant contributor to pain severity was PCS(β=0.555)and BMI(β=0.239),to moving capacity was K-L grade(β=0.520)and to PCS(β=0.313),and to a JKOM score was PCS(β=0.485)and K-L grade(β=0.421),respectively.CONCLUSION The results suggest that pain catastrophizing as well as biological factors were associated with clinical outcomes in female patients with knee OA,irrespective of radiographic severity.

Effect of aging on the relationship between capillary supply and muscle fiber size

A quantitative analysis of capillary supply to skeletal muscle is important for understanding the upper limit of the capacity for delivery of oxygen and substrates to muscle cells. It has been well documented that the number of capillaries is altered by several factors including development, aging, and alteration of muscle activity level such as exercise training and inactivation. There is, however, a contradiction in animal studies for aging-related change in the number of capillaries. Human studies using biopsy technique also displayed an inconsistency on that point, in which capillary supply was not influenced or decreased with aging. This review discussed an inconsistency among studies for aging-related change in muscle capillary supply. In conclusion, the relationship between capillary supply and muscle fiber size is similar for both young and elderly population, and the morpho- logical balance between capillaries and each muscle fiber was maintained with advancing age.

Parabiotic strategy alleviate Alzheimer s neuropathology through peripheral cireulation

To investigate the impact of systemic circulation on Alzheimer's disease(AD)like neuropathology and the recruitment of peripheral immune cells to the brain in the pathogenic process of AD.We performed parabiotic surgeries between C57BL/6(B6)congenic APP/PS1 transgenic(Tg)mice(ParaAPP/PS1)and sex/age matched B6 congenic green-fluorescent-protein(GFP;βactin promoter)Tg mice(ParaWT)at3 to6 months.The mice remained parabiosed until 7 to 10 months,followed by dissection for tissue collection and analyses.

Strategies for Managing Chronic Pain: Case of a Skilled Orthopaedic Physician and Mini-Review

Epidemiological surveys have recently revealed a high prevalence of chronic musculoskeletal pain in Japan;however, 30% of the patients in the survey were not satisfied with their pain treatment. This indicates that standard strategies in the management of chronic pain are poorly shared among physicians in Japan. Herein we report a case of a patient with intractable chronic pain who is a skilled orthopaedic physician. A 43-year-old man who was a skilled orthopaedic surgeon presented at our center complaining of severe buttock pain especially around the right hip region for more than three years. At begging of pain onset, he was diagnosed with femoacetabular impingement syndrome (FAI) with labral tear. Despite biophysical interventions including twice surgeries and alternative conservative treatment, his pain persisted, and he occasionally had to take a day off work due to the severe pain. Therefore we had to evaluate his pathological condition using a multidimensional approach based on a biopsychosocial model. We had provided him with cognitive behavioral therapy (CBT) approach, and simultaneously suggestion for short leaving from work. Three months after the start of CBT training, his disabilities had begun to improve. About six months later, he could continue to do his work. Finally, 19 months have passed since we started implementing the CBT approach;he has regained both his previous work-life balance and his health, although the pain has not completely subsided. In conclusion, we think it is important for physicians treating chronic pain to learn the management strategies for chronic pain and to re-consider their management policy when conventional biomedical interventions were not succeeded, even in cases where medication and surgical intervention are warranted.

Effect of acupuncture at acupoint of Shenshu (BL 23) on the bones of ovariectomized rats

OBJECTIVE： To investigate the effect of acupuncture at acupoint of Shenshu （BL 23） in ovariectomized rats and sham-operated rats. METHODS： Female Sprague-Dawley rats were divided into the following four groups （n = 12 each）： sham operation only （Sham）, sham operation with acupuncture （Sham ＋ ACP）, ovariectomy only （OVX）, and ovariectomy with acupuncture （OVX ＋ ACP）. Operations were performed at the 9th week of age. Acupuncture of Shenshu （BL 23） was started at the 1 lth week of age and conducted 3 times per week until the 26th week of age. RESULTS： Among ovariectomized rats, the acupuncture-treated rats had significantly lower body weights and cross-linked N-telopeptide of type 1 collagen levels in the urine after 3 weeks of acu- puncture treatment, higher bone mineral density of the lumbar vertebra after 7 weeks, and smaller trabecular separation of the sixth lumbar vertebra, measured by micro-computed tomography, after 17 weeks than control rats. These effects were not observed in sham-operated rats. Blood concentrations of estradiol were significantly higher in the OVX ＋ ACP group than in the untreated group. Acupuncture treatment increased plasma testosterone levels in sham-operated rats, while this increase was not observed in OVX rats. CONCLUSION： Acupuncture of Shenshu （BL 23） prevents bone loss and structural changes by sup- pressing bone resorption.

Move More,Sit Less and Sleep Well:An analysis of WHO movement guidelines for children under 5 years of age

Insufficient physical activity(PA),prolonged sedentary behavior(SB)and inadequate sleep(SLP)are detrimental factors to population health.To address health issues caused by insufficient PA,excessive SB and poor SLP,the World Health Organization(WHO)updated PA and SB guidelines for all populations aged from 5 years to 65 years and older in 2020.For children under 5 years old,the WHO issued the first global guidelines for PA,SB and SLP(collectively refer to movement behaviors)in April 2019.The guidelines applied a holistic approach to promote health behaviors,filling the gap of no comprehensive global movement guidelines for young children.Although the guidelines for young children offer guidance for health promotion,some research and practice implications and other issues should be mentioned.This commentary includes considerations for the importance of the WHO guidelines for younger children,critical analysis of evidence for developing the guidelines,and recommendations for future research and practice.The aim of this paper is to further advance health research in younger populations.

The Prevalence and Trends of Obesity in Chinese Preschool Children from 1996 to 2019:A Meta-analysis

Purpose Understanding the prevalence and trends of obesity in preschool children is of critical importance for public health policy.Thus,the object of the present study was to assess the prevalence and trends of obesity in Chinese preschool children from 1996 to 2019,and to examine the differences among different population according to year,gender,age,urban/rural and geographical area.Methods Four online databases(Chinese National Knowledge Infrastructure,Wanfang Data Resource System,Weipu Chi-nese Journal Service Platform and PubMed)were searched for studies published from January 1990 to May 2019 using predefined inclusion/exclusion criteria.Random effects meta-analysis was used to calculate the prevalence of obesity.Results Forty-three studies with a total of 765,255 Chinese preschool children aged 3-6 years were included in this meta-analysis.The prevalence of obesity in the whole sample was 6.41%(95%CI:5.74%-7.78%,P<0.000,I^(2)=99.79%;obtained after trim-and-fill adjustment).There was no significant difference(P=0.222)in the prevalence of obesity during five peri-ods(1996-2000,2001-2005,2006-2010,2011-2015,2016-2019).The obesity prevalence of boys was higher than girls(P=0.007),and the obesity prevalence increased with age(P=0.000).In 2006-2010,the prevalence of obesity among urban areas was about three times than that of rural areas(P=0.001).However,the difference was decreased during 2011-2015(P=0.788).In rural areas,the obesity prevalence in 2011-2015 was two times more than that in 2006-2010(P=0.005).Geographical area was a strong determinant of heterogeneity for Chinese preschool children(P=0.001).Conclusion There was no significant difference of the obesity prevalence among any five-year periods from 1996 to 2019.The prevalence of obesity in boys was higher than girls and increased with age.Though the prevalence of obesity in rural area was lower than the urban area,the speed of the increasing of the prevalence after 2010 in rural area should be noted.Public health intervention such as physical activity promotion and nutrition education should be conducted on preschool children for obesity prevention to promote their healthy development.