Pre-proenkephalin 1 is Downregulated Under Unloading and is Involved in Osteoblast Biology.

Pre-proenkephalin 1 (Penk1) is a pro-neuropeptide that belongs to the typical opioid peptide's family, having analgesic properties. We previously found Penk1 to be the most downregulated gene in a whole gene profiling analysis performed in osteoblasts subjected to microgravity as a model of mechanical unloading. In this work, Penk1 downregulation was confirmed in the bones of two in vivo models of mechanical unloading: tail-suspended and botulinum toxin A (botox)-injected mice. Consistently, in the sera from healthy volunteers subjected to bed rest, we observed an inverse correlation between PENK1 and bed rest duration. These results prompted us to investigate a role for this factor in bone. Penk1 was highly expressed in mouse bone, but its global deletion failed to impact bone metabolism in vivo. Indeed, Penk1 knock out (Penk1-/-) mice did not show an overt bone phenotype compared to the WT littermates. Conversely, in vitro Penk1 gene expression progressively increased during osteoblast differentiation and its transient silencing in mature osteoblasts by siRNAs upregulated the transcription of the Sost1 gene encoding sclerostin, and decreased Wnt3a and Col1a1 mRNAs, suggesting an altered osteoblast activity due to an impairment of the Wnt pathway. In line with this, osteoblasts treated with the Penk1 encoded peptide, Met-enkephalin, showed an increase of Osx and Col1a1 mRNAs and enhanced nodule mineralization. Interestingly, primary osteoblasts isolated from Penk1-/- mice showed lower metabolic activity, ALP activity, and nodule mineralization, as well as a lower number of CFU-F compared to osteoblasts isolated from WT mice, suggesting that, unlike the transient inhibition, the chronic Penk1 deletion affects both osteoblast differentiation and activity. Taken together, these results highlight a role for Penk1 in the regulation of the response of the bone to mechanical unloading, potentially acting on osteoblast differentiation and activity in a cell-autonomous manner.

24-H movement behaviors and physical fitness in preschoolers: A compositional and isotemporal reallocation analysis.

Background/Objectives: This study examined the relationships between 24-h movement behaviors and physical fitness (PF) in preschool children. Methods: The study was conducted on 474 children aged 3-6 years in Zhuhai. Physical activity (PA) and sedentary behavior (SB) were collected by the accelerometer, and sleep time was assessed through the parent-report questionnaire. Balance, cardiorespiratory fitness (CRF), flexibility, muscle strength, muscular endurance, and speed-agility were measured using a balance beam test, 20 m shuttle run test, sit and reach test, handgrip test, sit-ups, and 4 × 10 m shuttle run test respectively. The compositional data analysis was used to examine the association between 24-h movement behaviors and PF, and the compositional isotemporal substitution analysis was used for the time reallocation. Results: The daily composition, adjusted for age, gender, and body mass index (BMI), was significantly associated with CRF (p < 0.001, r2 = 0.20), flexibility (p < 0.001, r2 = 0.07), muscular strength (p < 0.001, r2 = 0.37), muscular endurance (p < 0.001, r2 = 0.26), and speed-agility (p < 0.001, r2 = 0.26). The addition of moderate-to-vigorous PA (MVPA) at the expense of SB and sleep, MVPA at the cost of sleep, was associated with significant muscular strength and speed-agility improvements respectively. The impact of SB and sleep replacing MVPA is stronger than MVPA replacing SB and sleep on muscular strength. Conclusion: These findings offer useful insight for the replacement of movement behaviors within the recommended range to facilitate PF development in early childhood.

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.

Parental role-modeling on 24-hour movement behaviors among preschoolers during the COVID-19 pandemic.

INTRODUCTION: Little is known about the association between parents' and children's 24-h movement behaviors during the pandemic. This cross-sectional study examined the association between the 24-h movement behaviors of parents and their preschoolers and investigated sex differences in this association. METHODS: A total of 1740 preschoolers (4.5 ± 0.8 years old, 50.3% boys) and their parents (35.4 ± 4.9 years old, 24.3% males) in China participated in this study and provided valid and complete data. Parents completed an online survey or a written questionnaire in the period between October and December 2020. Preschoolers' and parents' movement behaviors (physical activity [PA], sedentary behavior [SB], screen time, and sleep) and demographic information were reported by the parents. Generalized linear models and logistic regression models were performed. RESULTS: Positive associations were found between parents' and preschoolers' moderate-to-vigorous intensity PA (ß = 0.28; 95% confidence interval [CI]: 0.20, 0.36), total PA (ß = 0.21; 95% CI: 0.17, 0.24), and sleep (ß = 0.05; 95% CI: 0.03, 0.06) with no apparent sex difference. No significant association was found between parents' and preschoolers' SB or screen time. Girls were more likely to meet all three 24-h movement guidelines when their parents met them (odds ratio = 2.38; 95% CI: 1.42, 4.01), but the relationship was not significant for boys. CONCLUSIONS: Parental role-modeling was positively associated with children's PA and sleep. This finding suggests that supporting parents' movement behaviors has the potential to promote a healthy lifestyle among preschoolers.

24-Hour movement behaviors and executive functions in preschoolers: A compositional and isotemporal reallocation analysis.

This cross-sectional study explored the relationship between 24-hour movement behaviors and executive function (EF) in preschool children. A total of 426 Han Chinese preschoolers (231 males; 3.8 ± 0.6 years old) from Zhuhai, Guangdong Province, China were selected from October 2021 to December 2021. Accelerometers were used to measure physical activity (PA) and sedentary behavior (SB), while sleep duration was obtained via a parent-report questionnaire. Components of EF (cognitive flexibility, inhibitory control, and working memory) were assessed using computerized behavioral tasks. The daily composition was significantly associated with inhibitory control and working memory. Inhibitory control improvements were linked to the addition of moderate-to-vigorous physical activity (MVPA) at the expense of SB and sleep. The reallocation between MVPA, SB, sleep, and light physical activity yielded a significant association with working memory.

Do acute and chronic physical activity interventions affect the cognitive function of preschool children? A meta-analysis.

This meta-analysis aims to investigate the effects of acute and chronic physical activity (PA) interventions on multiple domains of cognitive function (CF) in preschool children. Electronic databases (PsycINFO, PubMed, SPORTDiscus, Embase, Web of Science, MEDLINE, and ERIC) were searched for relevant studies between January 2000 and February 2022. Studies that examined the effects of acute or chronic physical activity interventions on CF in preschool children aged 2-6 years were included. A total of 16 articles were eligible for this meta-analysis. Results showed that there was no effect of acute PA interventions on CF (Hedges' g = 0.04; 95% CI = -0.12, 0.19). Chronic PA interventions had a moderate and positive effect on overall CF (Hedges' g = 0.49; 95% CI = 0.29, 0.69), a large effect on perception (Hedges' g = 1.19; 95% CI = 0.64, 1.75), and a moderate effect on inhibitory control (Hedges' g = 0.73; 95% CI = 0.22, 1.24). The moderator analyses showed that overall CF performance was significantly moderated by intervention modality and assessment of cognitive outcomes, and no other moderator (study design, sample size, frequency, duration, and session length) was found to have an effect. Chronic PA intervention might be a promising way to promote multiple aspects of CF, especially executive function and perception. Future studies should explore the effect of different intensities of PA on the CF of preschool children to discern the most effective PA prescription to, in turn, enhance the CF of preschool children.

Associations between exposure to ambient particulate matter and advanced liver fibrosis in Chinese MAFLD patients.

BACKGROUND & AIMS: Liver fibrosis is an important feature in patients with metabolic dysfunction-associated fatty liver disease (MAFLD). This study aimed to explore the association between long-term ambient particulate matter (PM) exposure and advanced liver fibrosis (ALF) in MAFLD participants. METHODS: A cross-sectional study of 23170 adults recruited from 33 provinces of China from 2010 to 2020. ALF was detected using the nonalcoholic fatty liver disease fibrosis score (NFS). The annual average levels of particulate matter with aerodynamic diameters of ≤ 1 µm (PM1), ≤ 2.5 µm (PM2.5) and ≤ 10 µm (PM10) were calculated using validated spatiotemporal models. Generalized additive models were applied to analyze the association between PM and ALF in patients with MAFLD. RESULTS: One-year exposure to higher levels of all PM was found to increase the risk of ALF, with odds ratios (ORs) of 1.10 (95% CI 1.06-1.14), 1.05 (1.03-1.07), and 1.03(1.02-1.04) for each 10 µg/m3 increase in PM1, PM2.5 and PM10, respectively. With the dissection of the impact of PM1 in PM2.5, PM2.5 in PM10 and PM1 in PM10, we found that PM2.5 had a stronger impact on ALF (both Pinteraction＜0.05) in comparison with PM1 and PM10. CONCLUSIONS: Long-term exposure to PM is associated with ALF in patients with MAFLD, with PM2.5 playing a dominant role.

Hepatitis E virus seropositivity in an ethnically diverse community blood donor population.

BACKGROUND AND OBJECTIVES: Hepatitis E virus (HEV) is an underrecognized and emerging infectious disease that may threaten the safety of donor blood supply in many parts of the world. We sought to elucidate whether our local community blood supply is at increased susceptibility for transmission of transfusion-associated HEV infections. MATERIALS AND METHODS: We screened 10,002 randomly selected donations over an 8-month period between 2017 and 2018 at the Stanford Blood Center for markers of HEV infection using commercial IgM/IgG serological tests and reverse transcriptase quantitative polymerase chain reaction assays (RT-qPCR). Donor demographic information, including gender, age, self-identified ethnicity, location of residence and recent travel, were obtained from the donor database and used to generate multivariate binary logistic regressions for risk factors of IgG seropositivity. RESULTS: A total of 10,002 blood donations from 7507 unique donors were screened, and there was no detectable HEV RNA by RT-qPCR. The overall seropositivity rate was 12.1% for IgG and 0.56% for IgM. Multivariate analysis of unique donors revealed a significantly higher risk of IgG seropositivity with increasing age, White/Asian ethnicities and residence in certain local counties. CONCLUSION: Although HEV IgG seroprevalence in the San Francisco Bay Area is consistent with ongoing infection, the screening of a large donor population did not identify any viraemic blood donors. While HEV is an underrecognized and emerging infection in other regions, there is no evidence to support routine blood screening for HEV in our local blood supply currently; however, periodic monitoring may still be required to assess the ongoing risk.

Associations between long-term exercise participation and lower limb joint and whole-bone geometry in young and older adults.

Introduction: Features of lower limb bone geometry are associated with movement kinematics and clinical outcomes including fractures and osteoarthritis. Therefore, it is important to identify their determinants. Lower limb geometry changes dramatically during development, partly due to adaptation to the forces experienced during physical activity. However, the effects of adulthood physical activity on lower limb geometry, and subsequent associations with muscle function are relatively unexplored. Methods: 43 adult males were recruited; 10 young (20-35 years) trained i.e., regional to world-class athletes, 12 young sedentary, 10 older (60-75 years) trained and 11 older sedentary. Skeletal hip and lower limb geometry including acetabular coverage and version angle, total and regional femoral torsion, femoral and tibial lateral and frontal bowing, and frontal plane lower limb alignment were assessed using magnetic resonance imaging. Muscle function was assessed recording peak power and force of jumping and hopping using mechanography. Associations between age, training status and geometry were assessed using multiple linear regression, whilst associations between geometry and muscle function were assessed by linear mixed effects models with adjustment for age and training. Results: Trained individuals had 2° (95% CI:0.6°-3.8°; p = 0.009) higher femoral frontal bowing and older individuals had 2.2° (95% CI:0.8°-3.7°; p = 0.005) greater lateral bowing. An age-by-training interaction indicated 4° (95% CI:1.4°-7.1°; p = 0.005) greater acetabular version angle in younger trained individuals only. Lower limb geometry was not associated with muscle function (p > 0.05). Discussion: The ability to alter skeletal geometry via exercise in adulthood appears limited, especially in epiphyseal regions. Furthermore, lower limb geometry does not appear to be associated with muscle function.

Development and evaluation of a blocking ELISA for serological diagnosis of equine infectious anemia.

Equine infectious anemia (EIA) is an important viral disease characterized by persistent infection in equids worldwide. Most EIA cases are life-long virus carriers with low antibody reactions and without the appearance of clinical symptoms. A serological test with high sensitivity and specificity is required to detect inapparent infection. In this study, a B-cell common epitope-based blocking ELISA (bELISA) was developed using a monoclonal antibody together with the EIAV p26 protein labelled with HRP. The test has been evaluated against the standard and with field serum samples globally. This bELISA test can be completed within 75 min, and the sensitivity is higher than those of either the AGID or one commercial cELISA kit. This bELISA assay was 8-16 times more analytically sensitive than AGID, and 2 to 4 times more analytically sensitive than one cELISA kit by testing three sera from the USA, Argentina, and China, respectively. The 353 serum samples from Argentina were tested, in comparison with AGID, the diagnostic sensitivity and specificity of our bELISA assay were 100% (154/154) and 97.0% (193/199), respectively, and the accuracy of the bELISA test was 98.3%. The bELISA test developed in this study is a rapid, sensitive, specific method for the detection of EIAV infection, and could be a promising candidate for use in the monitoring of the EIA epidemic worldwide. KEY POINTS: • A universal epitope-based blocking enzyme-linked immunosorbent assay (bELISA) was developed for detection of antibodies to EIAV. • The bELISA assay can be used to test EIAV serum samples from different regions of the world including North America, South America, Europe, and Asia. • The bELISA assay was evaluated in three different international labs and showed a better performance than other commercial kits.

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.

Long-term human spaceflight and inflammaging: Does it promote aging?

Spaceflight and its associated stressors, such as microgravity, radiation exposure, confinement, circadian derailment and disruptive workloads represent an unprecedented type of exposome that is entirely novel from an evolutionary stand point. Within this perspective, we aimed to review the effects of prolonged spaceflight on immune-neuroendocrine systems, brain and brain-gut axis, cardiovascular system and musculoskeletal apparatus, highlighting in particular the similarities with an accelerated aging process. In particular, spaceflight-induced muscle atrophy/sarcopenia and bone loss, vascular and metabolic changes, hyper and hypo reaction of innate and adaptive immune system appear to be modifications shared with the aging process. Most of these modifications are mediated by molecular events that include oxidative and mitochondrial stress, autophagy, DNA damage repair and telomere length alteration, among others, which directly or indirectly converge on the activation of an inflammatory response. According to the inflammaging theory of aging, such an inflammatory response could be a driver of an acceleration of the normal, physiological rate of aging and it is likely that all the systemic modifications in turn lead to an increase of inflammaging in a sort of vicious cycle. The most updated countermeasures to fight these modifications will be also discussed in the light of their possible application not only for astronauts' benefit, but also for older adults on the ground.

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.

Association of fast-food restaurants with overweight and obesity in school-aged children and adolescents: A systematic review and meta-analysis.

We aimed to explore associations between the accessibility of fast-food restaurants (FFRs) and weight-related outcomes in children and adolescents through a systematic review and meta-analysis of studies. We searched three databases for studies published before October 21, 2022. Study quality was assessed using the National Institutes of Health's Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. Meta-analysis was performed, and the leave-one-out method was used for sensitivity analysis. A total of 60 studies were included. According to our analysis, FFRs within a smaller buffer radius from residences or that provide unhealthy foods may have a more significant influence on children's and adolescents' weight. Children of younger ages and girls may have a higher possibility of being overweight due to FFRs. Though we could hardly avoid bias, the estimates in low-and middle-income countries (only six studies) are much higher than those in high-income countries (54 studies). More research analyses based on microscope data and individual economic levels are needed. This study yields quantitative results, provides policymakers and urban planners with a theoretical support for building resilient and sustainable human settlements, and promotes the translation of research findings from public health to environmental planning.

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.

Longitudinal Shifts in Movement Behaviors during the COVID-19 Pandemic: Relations to Posttraumatic Stress Disorder among University Students.

This study examined the longitudinal changes of movement behaviors and their relationships with posttraumatic stress disorder (PTSD) among university students during the coronavirus disease 2019 in China. A total of 569 university students completed online surveys twice (Time 1: between December 2020 and January 2021; Time 2: between November and December 2021). Physical activity, sedentary behavior, sleep duration and quality, as well as PTSD were self-reported. According to Canadian 24-h movement guidelines, the longitudinal shifts in each movement behavior from Time 1 to Time 2 were divided into four categories (consistently meeting the guidelines, from meeting to not meeting the guidelines, from not meeting to meeting the guidelines, and consistently not meeting the guidelines). Generalized linear mixed models were conducted using 410 valid responses (20.2 ± 1.0 years old at Time 2, 41.2% males). From Time 1 to Time 2, 22.2%, 2.0%, and 45.6% of the students consistently met the physical activity, sedentary behavior, and sleep guidelines, respectively. Compared to those who consistently met the sedentary behavior guideline, students who consistently failed to meet or changed from meeting to not meeting the guidelines had higher levels of PTSD. Students who had poor sleep quality at both time points or changed from good to bad sleep quality had higher levels of PTSD than those who maintained good sleep quality over time. Compared to those who consistently failed to meet the guideline, students who consistently met the PA guideline had higher levels of PTSD. These findings highlight the needs to improve and maintain healthy behaviors for mental health.

The effectiveness of Facebook as a social network intervention to increase physical activity in Chinese young adults.

Introduction: Facebook, one of the worlds' most popular online social networks, is easy to access and cost-effective. Its use to enhance individual's physical activity (PA) participation should be examined. This research reviews the effectiveness and successful features of Facebook for influencing PA behaviors in young adults (Study 1), and empirically examines the efficacy of the features purported in increase PA via a Facebook intervention (Study 2). Methods: In Study 1, PubMed, Medline, SPORT Discus, ERIC, and Embase were searched for articles that identified successful features and effectiveness of Facebook PA interventions published between January 2005 and February 2022. In Study 2, a 4-week Facebook PA intervention with University students was conducted using features identified in Study 1. The PA behaviors with objective (ActiGraph) and subjective (questionnaire) measures, perceived PA level, stage of readiness, effectiveness, and efficiency of Facebook were examined. Results: Study 1 concluded that the most effective strategies for producing significant PA changes in young adults using a PA Facebook intervention included the following: Adding behavior modification (goal setting and self-monitoring), using influence agents, recruiting members of an existing network with the snowball technique, being attentive to group size, enhancing social support with motivational quotes, interactive posts, opinion polls, increasing tailored feedback, and providing educational information. Study 2 found no significant difference in PA between the intervention and the control groups, as measured objectively, but the subjective reporting of PA behavior was higher in the intervention group. Compared to the control group, the Facebook PA intervention group reported more positive change in perceived stage of readiness in PA participation, commuting type, sport type, sport venue, sport emotion, and fast breathing or sweating. When features were ranked by the Facebook PA intervention group, motivation (supports from your friends) and tailored feedback (the responses from your friends are really personal and fits you) were the top two ranked features. Conclusion: The use of influence agents in the Facebook PA intervention could address exercise preference and facilitate higher program engagement. Significant differences related to commuting type, sport types, sport venue barriers, and exercise intensity across groups were noteworthy and warrant additional investigation in the future.

Movement behaviors and posttraumatic stress disorder during the COVID-19 pandemic: A retrospective study of Chinese university students.

Background/objective: This study aimed to examine the associations between physical activity (PA), sedentary behavior, sleep and posttraumatic stress disorder (PTSD) among undergraduate students during the coronavirus disease 2019 (COVID-19) pandemic in China. Methods: A total of 3178 university students responded to an online questionnaire between December 2020 and January 2021. Participants self-reported the time they spent on PA, screen time and sleep after (over the past seven days) and during the outbreak peak (from January to March 2020). Their sleep quality was measured using the Chinese version of the Pittsburgh Sleep Quality Index. The Chinese version of the Posttraumatic Stress Disorder Checklist - Civilian Version was used to measure PTSD. Logistic regressions and generalized linear mixed models were conducted. Results: The final analysis included data from 2070 university students (20.2 ±â€¯1.3 years old, 37.0% males). The prevalence of PTSD was 7.1%. Better sleep quality both during and after the outbreak peak, and longer sleep duration after the outbreak peak were associated with a lower odds ratio of having PTSD and lower re-experiencing, avoidance and hyperarousal scores. Higher total PA levels during the outbreak peak were associated with a higher odds ratio of having PTSD and higher levels of re-experiencing and avoidance. Conclusion: Sleep quality and duration were negatively associated with PTSD among university students during the COVID-19 pandemic. The associations between PA, screen time and PTSD require further examination. Future interventions to enhance mental health could consider targeting university students' sleep hygiene.

Dissociation of Bone Resorption and Formation in Spaceflight and Simulated Microgravity: Potential Role of Myokines and Osteokines?

The dissociation of bone formation and resorption is an important physiological process during spaceflight. It also occurs during local skeletal unloading or immobilization, such as in people with neuromuscular disorders or those who are on bed rest. Under these conditions, the physiological systems of the human body are perturbed down to the cellular level. Through the absence of mechanical stimuli, the musculoskeletal system and, predominantly, the postural skeletal muscles are largely affected. Despite in-flight exercise countermeasures, muscle wasting and bone loss occur, which are associated with spaceflight duration. Nevertheless, countermeasures can be effective, especially by preventing muscle wasting to rescue both postural and dynamic as well as muscle performance. Thus far, it is largely unknown how changes in bone microarchitecture evolve over the long term in the absence of a gravity vector and whether bone loss incurred in space or following the return to the Earth fully recovers or partly persists. In this review, we highlight the different mechanisms and factors that regulate the humoral crosstalk between the muscle and the bone. Further we focus on the interplay between currently known myokines and osteokines and their mutual regulation.