Longitudinal Trajectories of Television Watching Across Childhood and Adolescence Predict Bone Mass at Age 20 Years in the Raine Study

The association between screen time trajectories and the comorbidity of depression and anxiety

Depression and anxiety are often comorbid among adolescents. Adolescent screen time changes over time. This study investigates the association between screen time trajectories and the comorbidity of depression and anxiety from a longitudinal perspective. The data were collected from an ongoing prospective puberty cohort which was established in 2014 from Chongqing, China. 838 participants (52.03 % female; wave 1 mean age = 8.62, SD = 1.15) were followed up from 2014 to 2020. Questions about screen time were administered every six months. Trajectories of screen time were identified using latent class growth analysis. Children's Depression Inventory (CDI) and Screen for Child Anxiety Related Disorders (SCARED) were used to measure depression and anxiety. Latent profile analysis was used to identify the subtypes of comorbidity of depression and anxiety. Logistic regression was used to explore the association between screen time trajectory and the comorbidity of depression and anxiety. Three distinct trajectories of screen time were identified: Group Low (68.26 %) had consistently low screen time, Group High (26.37 %) had high screen time and Group Increasing (5.37 %) was characterized by an increasing screen time. Four subtypes of the comorbidity of depression and anxiety were fitted ("High comorbidity", "Low comorbidity", "Low depression symptoms" and "No symptoms"). Group Increasing and Group High were associated with "Low comorbidity" and "Low depression symptoms". Group Increasing was more likely to be the "high comorbidity" both boys and girls. However, Group High was associated with "high comorbidity" only in girls. The results of this study may inform future research and provide possible intervention targets.

Physical Activity and Sedentary Behavior on Bone Health in Adults: A Systematic Review

The objective was to analyze the longitudinal associations of physical activity (PA) and Sedentary behavior (SB) on bone health indicators (BHI) in healthy young adults. Articles were selected from five databases and 17 longitudinal studies were selected after meeting the inclusion and exclusion criteria. Among these, only one study assessed the association between childhood PA and adult BHI, the results showed no significant association between PA and BHI. Positive associations between adolescence and adulthood were observed between PA with bone mineral content and density and bone microarchitecture. In adulthood, the results were divergent; among the three studies located, two found a positive association. SB was negatively associated with bone mineral density and content from childhood to adulthood. However, from adolescence to adulthood, it was negatively associated with total tibia area but positively associated with trabecular thickness, cortical thickness, and cortical bone mineral. The evidence of the positive effect of PA and its intensities between adolescence and adulthood on BHI seems to be more consolidated, and it is still necessary to understand the role of intensities, volume of PA and SB in different periods of life with BHI in adulthood.

Association between sedentary behavior and bone mass, microstructure and strength in children, adolescents and young adults: a systematic review

Sedentary behavior (SED) research is currently receiving increasing attention in the field of public health. While it has been shown to have negative effects on cardiovascular or metabolic health, there is limited knowledge regarding the relationship between SED and bone health in children, adolescents, and young adults. Thus, the purpose of this review is to investigate the associations between SED and bone health status, specifically bone mass, microstructure, and strength. A comprehensive literature search was conducted across five electronic databases, including EMBASE, PubMed, Medline, Cochrane, Web of Science and CNKI. The inclusion criteria were as follows: healthy participants aged 24 years or younger, with measured SED and measured bone outcomes. The quality of the included articles was assessed using the National Institute of Health Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. After excluding, the final sample included 25 cross-sectional, 9 observational and 2 both cross-sectional and longitudinal studies. Among these, seven were rated as 'high quality', twenty-three were rated as 'moderated quality', and six were rated as 'low quality' according to the quality assessment criteria. After summarizing the evidence, we found no strong evidence to support an association between BMC or BMD and SED, even when considering gender or adjusting for moderate-to-vigorous physical activity (MVPA). However, a strong level of evidence was found indicating a negative relationship between objectively measured SED and cortical bone mineral density (Ct.BMD) in the tibia or stiffness index (SI) in the Calcaneus across all age groups. While the association between adverse bone health outcomes and SED still cannot be confirmed due to insufficient evidence, these findings suggest that bone microstructure and strength may be more sensitive to SED than bone mass. Thus, further evidence is needed to fully understand the connection between sedentary behavior and bone health, particularly regarding the relationship between SED and bone strength.

Associations between socioeconomic status and screen time among children and adolescents in China: A cross-sectional study

Background

Socioeconomic status (SES) is an important determinant of screen time (ST) in children and adolescents, however, the association between SES and ST is not fully understood in China. This study aimed to investigate the association between SES and ST (operationalized as meeting the ST guidelines; no more than 2 hours per day) in Chinese children and adolescents.

Methods

Cross-sectional data of 2,955 Chinese children and adolescents aged 8 to 17(53.4% girls) were used. SES was measured using indicators of parental education and perceived family wealth. ST was assessed with detailed items from the Health Behaviour School-aged Children survey questionnaires. Descriptive statistics and a Chi-square test were used to report the sample characteristics and analyse ST differences across different sociodemographic groups. A binary logistic regression was then applied to analyse the association of SES indicators with ST in children and adolescents.

Results

Overall, 25.3% of children and adolescents met the ST guidelines. Children and adolescents with higher parental education levels were 1.84 [95% CI 1.31–2.57; father] and 1.42 [95% CI 1.02–1.98; mother] times more likely to meet the ST guidelines than those with lower parental education levels. Associations between SES and ST varied across sex and grade groups. Moreover, the associations of SES with ST on weekdays and weekends were different.

Conclusions

This study demonstrated the association between SES and ST in children and adolescents, highlighting the importance of targeting children and adolescents with low SES levels as an intervention priority. Based on our findings, specific interventions can be tailored to effectively reduce ST. Future studies are encouraged to use longitudinal or interventional designs to further determine the association between SES and ST.

Relationship between TV watching during childhood and adolescence and fitness in adulthood in the Raine Study cohort

To investigate: (1) whether TV watching habits throughout childhood and adolescence, a proxy of sedentary behaviour, impacted cardiorespiratory fitness (CRF) in adulthood, and (2) whether any potential impact of TV watching in childhood and adolescence on CRF in adulthood was changed by adult physical activity (PA) levels. A longitudinal study with questionnaire data available regarding TV watching collected at ages 5, 8, 10, 14, 17 and 20 yrs, allowed trajectories of TV watching to be developed. At age 28 yrs, participants completed a V̇O₂peak test and the International Physical Activity Questionnaire. General linear models tested for differences in CRF (time to exhaustion TTE and V̇O₂peak mL·kg^-1·min^-1) between TV watching trajectories. The secondary analysis tested the potential effect current PA levels has on the relationship between TV trajectory and fitness. In total, 449 participants [male n = 255 (56.8%), 28.3 ± 0.5 yrs; female n = 194 (43.2%), 28.2 ± 0.4 yrs] were included in the study. Three distinct trajectories of TV watching were identified: High TV, Increasing TV and Low TV. CRF was lowest in the High TV watching trajectory and increased progressively from High to Increasing TV and Increasing to Low TV (all P < .05). Within each of the TV trajectories, those engaging in high levels of current PA had greater CRF than those engaging in low and moderate PA. TV watching in childhood and adolescence negatively impacts upon adult fitness at the age of 28 years. However, this negative impact of historical TV watching on CRF can largely be attenuated by engaging in higher levels of PA in adulthood.

Physical activity estimated by osteogenic potential and energy expenditure has differing associations with bone mass in young adults: the raine study

Ground impacts during physical activity may be important for peak bone mass. We found differences in how energy expenditure and impact scores estimated from a physical activity questionnaire related to bone health in young adults. Using both estimate types can improve our understanding of the skeletal benefits of physical activity.

PURPOSE

It is unclear whether mechanical loading during physical activity, estimated from physical activity questionnaires which assess metabolic equivalents of task (METs), is associated with skeletal health. This longitudinal study investigated how physical activity loading scores, assessed at ages 17 and 20 years, (a) compares with physical activity measured in METs, and (b) is associated with bone mass at age 20 years.

METHODS

A total of 826 participants from the Raine Study Gen2 were assessed for physical activity energy expenditure via the International Physical Activity Questionnaire (IPAQ) at age 17 and 20 years. Loading scores (the product of peak force and application rate) per week were subsequently estimated from the IPAQ. Whole-body and appendicular bone mineral density (BMD) at age 20 years were assessed by dual-energy X-ray absorptiometry.

RESULTS

Bland-Altman minimal detectable difference for physical activity Z- scores at age 17 and 20 years were 1.59 standard deviations (SDs) and 1.33 SDs, respectively, greater than the a priori minimal clinically important change of 0.5 SDs. Loading score, but not IPAQ score, had significant positive associations with whole-body and leg BMD after adjustment for covariates (β = 0.008 and 0.012 g/cm², respectively, for age 17 and 20 years loading scores). IPAQ score at age 20 years, but not loading score, had a significant positive association with arm BMD (β = 0.007 g/cm²).

CONCLUSION

This study revealed disagreement in associations of self-reported METs and loading score estimates with bone health in young adults. Coupling traditional energy expenditure questionnaire outcomes with bone-loading estimates may improve understanding of the location-specific skeletal benefits of physical activity in young adults.

Osteoporosis in 10 years time: a glimpse into the future of osteoporosis

Patients living with osteoporosis are projected to increase dramatically in the next decade. Alongside the forecasted increased societal and economic burden, we will live a crisis of fractures. However, we will have novel pharmacological treatment to face this crisis and, more importantly, new optimized treatment strategies. Fracture liaison services will be probably implemented on a large scale worldwide, helping to prevent additional fractures in high-risk patients. In the next decade, novel advances in the diagnostic tools will be largely available. Moreover, new and more precise fracture risk assessment tools will change our ability to detect patients at high risk of fractures. Finally, big data and artificial intelligence will help us to move forward into the world of precision medicine. In the present review, we will discuss the future epidemiology and costs of osteoporosis, the advances in early and accurate diagnosis of osteoporosis, with a special focus on biomarkers and imaging tools. Then we will examine new and refined fracture risk assessment tools, the role of fracture liaison services, and a future perspective on osteoporosis treatment.

Technology integration for young children during COVID-19: Towards future online teaching

To support young children's learning during the coronavirus 2019 (COVID-19) pandemic, preschool educators in Hong Kong were required to teach with digital technologies. In this study, 1035 educators from 169 preschools reported their views and practices in an online survey, which we examined via multilevel mixed-response analysis and thematic analysis. More than half of the respondents (53%) expected future online teaching to continue, and only 11% of educators believed that parents would reject this form of delivery. Administrators and teaching assistants were more likely than teachers to expect online preschool teaching to continue in the future. In addition, respondents with existing online platform experience, who taught the upper levels of preschool, or incorporated specific teaching practices (eg, after the online lesson, they assessed children and assigned homework tasks), were more likely than others to expect online teaching in the future. Many of these respondents also reported (a) difficulty with engaging their children when online and (b) inadequate support from parents for learning activities, which reduced the respondents' perceived likelihood of future online teaching. Administrators and teaching assistants were more likely than teachers to believe that parents would accept online teaching in the future. Respondents who felt they had inadequate training to teach online, children in families with inadequate technical skills and parents who believed that online lessons harmed children's well-being, were less likely than others to believe that parents would accept online teaching in the future. These educators believed that online learning communities could connect parents and schools and foster interaction that could help align with educator's support for children's learning needs.

Screen Time and Bone Status in Children and Adolescents: A Systematic Review

Introduction: Technological advances over the last 2 decades have led to an increase in the time spent by children and youth engaged in screen-based activities, and growing recognition of deleterious effects on health. In this systematic review of cohort and cross-sectional studies, we assess current data on the relationship between screen time and bone status in children and teenagers. Methods: We searched PUBMED and SCOPUS databases for studies of children and adolescents that assessed screen time and bone status, determined by measuring bone mineral content or density, bone stiffness index, bone speed of sound, bone broadband ultrasound attenuation, or frame index. Searches were limited to studies published between 1900 and 2020, and performed in accordance with Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines. The studies included were evaluated using the Newcastle-Ottawa quality assessment scale. Results: Ten cohort and cross-sectional studies including pediatric population were selected. The combined study population was 20,420 children/adolescents, of whom 18,444 participated in cross-sectional studies. Four studies assessed the effects of total screen time, seven the consequences of TV viewing time, and six the effects of recreational computer use on bone health. Our findings indicate an inverse association between total and weekly screen time and bone health in children and adolescents. In 57% of the studies included also a negative correlation between television viewing time and bone status was observed, while recreational computer time did not have a significant impact on bone health. According to the only four studies that included dietetic factors, no relevant differences were found between calcium intake and screen time or bone broadband ultrasound attenuation and bone speed of sound. Conclusions: Review of the literature of the past three decades provides strong support for comprehensive education of screen time on bone status. The findings of this systematic review support a negative association between screen time and bone status in children and adolescents, with a different impact when considering the different technological devices. As peak bone mass in adolescents is the strongest predictor of osteoporosis risk, strategies aimed at improving bone health should incorporate conscious use of digital technology.

Osteosarcopenia in Reproductive-Aged Women with Polycystic Ovary Syndrome: A Multicenter Case-Control Study

CONTEXT

Osteosarcopenia (loss of skeletal muscle and bone mass and/or function usually associated with aging) shares pathophysiological mechanisms with polycystic ovary syndrome (PCOS). However, the relationship between osteosarcopenia and PCOS remains unclear.

OBJECTIVE

We evaluated skeletal muscle index% (SMI% = [appendicular muscle mass/weight (kg)] × 100) and bone mineral density (BMD) in PCOS (hyperandrogenism + oligoamenorrhea), and contrasted these musculoskeletal markers against 3 reproductive phenotypes (i): HA (hyperandrogenism + eumenorrhea) (ii); OA (normoandrogenic + oligoamenorrhea) and (iii), controls (normoandrogenic + eumenorrhea). Endocrine predictors of SMI% and BMD were evaluated across the groups.

DESIGN, SETTING, AND PARTICIPANTS

Multicenter case-control study of 203 women (18-48 years old) in New York State.

RESULTS

PCOS group exhibited reduced SMI% (mean [95% confidence interval (CI)]; 26.2% [25.1,27.3] vs 28.8% [27.7,29.8]), lower-extremity SMI% (57.6% [56.7,60.0] vs 62.5% [60.3,64.6]), and BMD (1.11 [1.08,1.14] vs 1.17 [1.14,1.20] g/cm2) compared to controls. PCOS group also had decreased upper (0.72 [0.70,0.74] vs 0.77 [0.75,0.79] g/cm2) and lower (1.13 [1.10,1.16] vs 1.19 [1.16,1.22] g/cm2) limb BMD compared to HA. Matsuda index was lower in PCOS vs controls and positively associated with SMI% in all groups (all Ps ≤ 0.05). Only controls showed associations between insulin-like growth factor (IGF) 1 and upper (r = 0.84) and lower (r = 0.72) limb BMD (all Ps < 0.01). Unlike in PCOS, IGF-binding protein 2 was associated with SMI% in controls (r = 0.45) and HA (r = 0.67), and with upper limb BMD (r = 0.98) in HA (all Ps < 0.05).

CONCLUSIONS

Women with PCOS exhibit early signs of osteosarcopenia when compared to controls likely attributed to disrupted insulin function. Understanding the degree of musculoskeletal deterioration in PCOS is critical for implementing targeted interventions that prevent and delay osteosarcopenia in this clinical population.

Negative impact of polycystic ovary syndrome on bone health: a systematic review and meta-analysis

BACKGROUND

Polycystic ovary syndrome (PCOS) has reproductive and metabolic aspects that may affect bone health. Controversial results from different studies regarding the risk of fractures, bone mineral density (BMD) or bone markers led to uncertainty whether PCOS might improve or deteriorate bone health.

OBJECTIVE AND RATIONALE

This study aimed to investigate the impact of PCOS on bone markers, BMD and fracture risk.

SEARCH METHODS

A systematic review and a meta-analysis were carried out. PubMed, EMBASE and Cochrane databases were searched for eligible studies from 1st of January of 1990 to 9th of October of 2018. Eligible studies enrolled women older than 18 years with PCOS, which should be diagnosed according to the Rotterdam Consensus, the Androgen Excess Society, the National Institutes of Health Consensus or the International Classification of Diseases. The studies were grouped according to patient mean BMI: <27 kg/m2 or ≥27 kg/m2. The results were polled as mean difference (MD), standardized MD (SMD) and hazard ratio (HR).

OUTCOMES

Overall, 921 studies were retrieved, and 31 duplicated studies were removed. After screening the titles and abstracts, 80 studies were eligible for full text reading. Of those, 23 studies remained for qualitative synthesis. With the exception of one study, all studies were considered high quality based on the Newcastle-Ottawa scale (NOS; score ≥6). Meta-analysis was performed in 21 studies, with a total of 31 383 women with PCOS and 102 797 controls. Women with PCOS with BMI <27 kg/m2 had lower BMD of the total femur (MD, -0.04; 95% CI, -0.07 to 0.00; I2 = 31%; P = 0.22) and spine (MD, -0.07; 95% CI, -0.13 to -0.01; I2 = 70%; P < 0.01) when compared with the control group, whereas for women with BMI ≥27 kg/m2 no difference was observed (femur: MD, 0.02; 95% CI, -0.02 to 0.05; I2 = 20%, P = 0.29; spine: MD, 0.02; 95% CI, -0.06 to 0.05; I2 = 0%; P = 0.84). Osteocalcin was remarkably reduced in women with PCOS with BMI <27 kg/m2 (SMD, -2.68; 95% CI, -4.70 to -0.67; I2 = 98%; P < 0.01), but in women with BMI ≥27 kg/m2, there were no differences between PCOS and controls. Few studies (n = 3) addressed the incidence of bone fractures in women with PCOS. The HR for total bone fractures did not identify differences between women with PCOS and controls.

WIDER IMPLICATIONS

On the basis of the available evidence, it is possible to assume that PCOS in women with BMI <27 kg/m2 is associated with reduced BMD in the spine and femur, and decreased bone formation, as manifested by lower levels of circulating osteocalcin. These findings suggest that bone parameters in PCOS may be linked, to some extent, to adiposity. These studies included premenopausal women, who have already achieved peak bone mass. Hence, further prospective studies are necessary to clarify the existence of increased risk of fractures in women with PCOS.

Cross-sectional and longitudinal associations between physical activity, sedentary behaviour and bone stiffness index across weight status in European children and adolescents

Background

The associations between physical activity (PA), sedentary behaviour (SB) and bone health may be differentially affected by weight status during growth. This study aims to assess the cross-sectional and longitudinal associations between PA, SB and bone stiffness index (SI) in European children and adolescents, taking the weight status into consideration.

Methods

Calcaneus SI was first measured by quantitative ultrasound among children aged 2–9 years old in 2007/08. It was measured again after 2 years in the IDEFICS study and after 6 years in the I. Family study. A sample of 2008 participants with time spent at sports clubs, watching TV and playing computer/games self-reported by questionnaire, and a subsample of 1037 participants with SB, light PA (LPA) and moderate-to-vigorous PA (MVPA) objectively measured using Actigraph accelerometers were included in the analyses. Weight status was defined as thin/normal and overweight/obese according to the extended International Obesity Task Force criteria. Linear mixed-effects models were used to estimate the cross-sectional and longitudinal associations between PA, SB and SI percentiles, stratified by weight status.

Results

The cross-sectional association between weekly duration of watching TV and SI percentiles was negative in thin/normal weight group (β = − 0.35, p = 0.008). However, baseline weekly duration of watching TV (β = − 0.63, p = 0.021) and change after 2 years (β = − 0.63, p = 0.022) as well as the change in weekly duration of playing computer/games after 6 years (β = − 0.75, p = 0.019) were inversely associated with corresponding changes in SI percentiles in overweight/obese group. Change in time spent at sports clubs was positively associated with change in SI percentiles after 2 years (β = 1.28, p = 0.001), with comparable effect sizes across weight status. In the subsample with accelerometer data, we found a positive cross-sectional association between MVPA and SI percentiles in thin/normal weight group. Baseline MVPA predicted changes in SI percentiles after 2 and 6 years in all groups.

Conclusions

Our results suggested the beneficial effect of PA on SI. However, the increasing durations of screen-based SB might be risk factors for SI development, especially in overweight/obese children and adolescents.

The trajectory of patterns of light and sedentary physical activity among females, ages 14-23

PURPOSE

Light physical activity (LPA) and patterns of sedentary behavior influence cardio-metabolic health independently of moderate-to-vigorous physical activity. Understanding the trajectory and determinants of these activity levels over time may provide insights relevant to public health practice.

METHODS

We measured a cohort of young women recruited in middle school (age 14) using accelerometry for 1 week and remeasured them in high school (age 17) and again at age 23 (n = 385). We assessed changes in LPA and patterns of sedentary behavior by hours in a day. We examined the association of social and contextual factors, including employment status, screen time, and neighborhood context with LPA and sedentary behavior patterns.

RESULTS

The amount of LPA decreased over time, while the length of LPA bouts tended to increase. Sedentary bout durations increased over time and sedentary breaks decreased. Sedentary time and bout length were correlated with internet use, rather than with TV or videogaming. Employment was associated with less sedentary time; being a student was associated with longer sedentary time and bouts.

CONCLUSIONS

Because LPA and sedentary breaks can be protective for cardio-metabolic health, and the duration of sedentary bouts increase as women age from adolescence to young adulthood, worksites and college campuses should remind employees and students to take frequent activity breaks when they use computers and the internet for long stretches.

Organized Sport Participation From Childhood to Adolescence Is Associated With Bone Mass in Young Adults From the Raine Study

There is a critical need for longitudinal cohort studies to consider the association of the cumulative exposure of physical activity during childhood and adolescence and bone mass. The aim of this study was to investigate the relationship between organized sports trajectories (that capture distinct and potentially meaningful patterns over critical developmental periods) and bone mass at age 20 years. Participation in organized sport was recorded by parental report at ages 5, 8, 10, 14, and 17 years in 984 offspring (48% female) of a pregnancy cohort (Raine Study). Latent class analysis identified three trajectory classes in each sex. In females, these were "consistent sport participators" (48%), "dropouts" (34%), and "non-participators" (18%); in males, "consistent sport participators" (55%), "dropouts" (37%), and "sport joiners" (8%). Whole-body bone mineral content (BMC) at age 20 years was assessed by dual-energy X-ray absorptiometry (DXA). At age 20 years, after adjustment for covariates measured at age 20 years, including height, lean mass, physical activity, calcium intake, serum 25-hydroxyvitamin D, alcohol, and smoking, males who were "consistent sport participators" had significantly greater whole-body and leg BMC than those who dropped out of sport (p < 0.001), whereas males who joined sports had significantly greater leg BMC than those who dropped out of sport (p = 0.002). Females in the "consistent sport participator" trajectory had significantly greater leg BMC than those who dropped out (all p = 0.004). Participation in organized sport during childhood and adolescence is associated with bone mass at age 20 years. Because attainment of optimal peak bone mass in young adulthood is protective against osteoporosis in later life, this may have long-term skeletal benefits. © 2018 American Society for Bone and Mineral Research.

Association of 12-Year Trajectories of Sitting Time With Frailty in Middle-Aged Women

Prolonged sitting time is associated with several health outcomes; limited evidence indicates associations with frailty. Our aims in this study were to identify patterns of sitting time over 12 years in middle-aged (ages 50-55 years) women and examine associations of these patterns with frailty in older age. We examined 5,462 women born in 1946-1951 from the Australian Longitudinal Study on Women's Health who provided information on sociodemographic attributes, daily sitting time, and frailty in 2001 and then again every 3 years until 2013. Frailty was assessed using the FRAIL (fatigue, resistance, ambulation, illness, loss of weight) scale (0 = healthy; 1-2 = prefrail; 3-5 = frail), and group-based trajectory analyses identified trajectories of sitting time. We identified 5 sitting-time trajectories: low (26.9%), medium (43.1%; referent), increasing (6.9%), decreasing (18.1%), and high (4.8%). In adjusted models, the likelihoods of being frail were statistically higher for women in the increasing (odds ratio (OR) = 1.29, 95% confidence interval (CI): 1.03, 1.61) and high (OR = 1.42, 95% CI: 1.10, 1.84) trajectories. In contrast, women in the low trajectory group were less likely to be frail (OR = 0.86, 95% CI: 0.75, 0.98), and there was no difference in the likelihood of frailty in the decreasing trajectory group. Our study suggests that patterns of sitting time over 12 years in middle-aged women predict frailty in older age.

Parental Education and Pre-School Children's Objectively Measured Sedentary Time: The Role of Co-Participation in Physical Activity

Parental co-participation in physical activity (PA) may be a beneficial parenting practice for diminishing children's sedentary time (ST). Less information is available, however, on the explanatory role of co-participation in PA regarding parental educational differences in children's ST. Preschool-aged children (N = 864, mean age 4.8, 52% boys) with their parents participated in a cross-sectional DAGIS (Increased Health and Wellbeing in Pre-schools) study between years 2015 and 2016. Children (N = 821) wore an accelerometer for one week. Parents were informed of their educational background, and the frequency of visits with their child in nature, to parks or playgrounds, their own yard, and indoor sport facilities (N = 808). Testing the associations required multiple regression analyses. Parents with a low educational background reported more frequent visits with their child to their own yard, and these visits were associated with children's lower ST. More highly educated parents co-visited indoor sport facilities more frequently, although this did not have a significant association with children's ST. More frequent visits in nature were associated with a lower ST at weekends, regardless of educational background. Future health promotion strategies should inform parents that frequent co-participation in PA, for example, in one's own yard, is beneficial for lowering children's ST.

A collaborative approach to adopting/adapting guidelines - The Australian 24-Hour Movement Guidelines for the early years (Birth to 5 years): an integration of physical activity, sedentary behavior, and sleep

BACKGROUND

In 2017, the Australian Government funded the update of the National Physical Activity Recommendations for Children 0-5 years, with the intention that they be an integration of movement behaviours across the 24-h period. The benefit for Australia was that it could leverage research in Canada in the development of their 24-h guidelines for the early years. Concurrently, the Grading of Recommendations Assessment, Development and Evaluation (GRADE) working group published a model to produce guidelines based on adoption, adaption and/or de novo development using the GRADE evidence-to-decision framework. Referred to as the GRADE-ADOLOPMENT approach, it allows guideline developers to follow a structured and transparent process in a more efficient manner, potentially avoiding the need to unnecessarily repeat costly tasks such as conducting systematic reviews. The purpose of this paper is to outline the process and outcomes for adapting the Canadian 24-Hour Movement Guidelines for the Early Years to develop the Australian 24-Hour Movement Guidelines for the Early Years guided by the GRADE-ADOLOPMENT framework.

METHODS

The development process was guided by the GRADE-ADOLOPMENT approach. A Leadership Group and Consensus Panel were formed and existing credible guidelines identified. The draft Canadian 24-h integrated movement guidelines for the early years best met the criteria established by the Panel. These were evaluated based on the evidence in the GRADE tables, summaries of findings tables and draft recommendations from the Canadian Draft Guidelines. Updates to each of the Canadian systematic reviews were conducted and the Consensus Panel reviewed the evidence for each behaviour separately and made a decision to adopt or adapt the Canadian recommendations for each behaviour or create de novo recommendations. An online survey was then conducted (n = 302) along with five focus groups (n = 30) and five key informant interviews (n = 5) to obtain feedback from stakeholders on the draft guidelines.

RESULTS

Based on the evidence from the Canadian systematic reviews and the updated systematic reviews in Australia, the Consensus Panel agreed to adopt the Canadian recommendations and, apart from some minor changes to the wording of good practice statements, keep the wording of the guidelines, preamble and title of the Canadian Guidelines. The Australian Guidelines provide evidence-informed recommendations for a healthy day (24-h), integrating physical activity, sedentary behaviour (including limits to screen time), and sleep for infants (<1 year), toddlers (1-2 years) and preschoolers (3-5 years).

CONCLUSIONS

To our knowledge, this is only the second time the GRADE-ADOLOPMENT approach has been used. Following this approach, the judgments of the Australian Consensus Panel did not differ sufficiently to change the directions and strength of the recommendations and as such, the Canadian recommendations were adopted with very minor alterations. This allowed the Guidelines to be developed much faster and at lower cost. As such, we would recommend the GRADE-ADOLOPMENT approach, especially if a credible set of guidelines, with all supporting materials and developed using a transparent process, is available. Other countries may consider using this approach when developing and/or revising national movement guidelines.

Preschool children's context-specific sedentary behaviours and parental socioeconomic status in Finland: a cross-sectional study

OBJECTIVES

This study examined the associations of parental socioeconomic status (SES) with preschoolers' objectively measured sedentary time (SED) over the course of a week and with parent-reported children's screen and reading times at home as indicators of sedentary behaviours (SB).

DESIGN

Cross-sectional.

SETTING

In years 2015 and 2016 in Finland.

PARTICIPANTS

864 children, aged 3-6 years, with their parents.

OUTCOME MEASURES

Children's accelerometer data were transformed into average SED minutes per hour in different contexts (preschool, home during preschool days, weekend and total). Parent-reported children's screen and reading times were expressed as average daily minutes. The SES indicators (maternal and paternal education and relative household income) were grouped into three categories. Linear or logistic regression analyses were used, with municipality, season, and children's gender and age as covariates. CIs were adjusted for clustering at the preschool group level.

RESULTS

Children with low maternal (β=17.21, 95% CI: 8.71 to 25.71) and paternal (β=10.54, 95% CI: 0.77 to 20.30) education had more overall screen time at home than their more advantaged counterparts. SES differences in overall screen time were mostly explained by TV viewing. Children with low as opposed to high maternal education (β=-2.66, 95% CI: -4.95 to -0.38) had less reading time at home. Children whose fathers were on the middle (β=-1.15, 95% CI: -2.01 to -0.29) educational level had less weekend SED than those with high paternal education. Otherwise, parental SES was not related to objectively measured SED.

CONCLUSIONS

The results of this study highlight the fact that the associations between parental SES and preschoolers' SB are dependent on the indicators of SES and SBs, and vary between different contexts. Generally, parental SES was not associated with SED, whereas some SES differences existed in screen time and reading time at home. Interventions aiming to diminish SES differences in children's SB should focus on home hours.

TRIAL REGISTRATION NUMBER

ISRCTN57165350.

Critical issues and current challenges in osteoporosis and fracture prevention. An overview of unmet needs

Osteoporosis is a silent disease with increasing prevalence due to the global ageing population. Decreased bone strength and bone quality is the hallmark of osteoporosis which leads to an increased risk of fragility fractures in elderly. It has been estimated that approximately ~50% of women will suffer during their lifetime from an osteoporotic fracture. This must be considered as a major health concern, as it has previously been established that fragility fracture has been associated with decreased quality of life due to increased disability, more frequent hospital admission and most importantly, osteoporotic fractures have been related to an augmented mortality risk. Anti-osteoporotic drugs are available for improving bone quality. Although there is access to these therapeutic options, there remain multiple unmet needs in the field of osteoporosis and fracture care, for example, the primary prevention of osteoporosis in young individuals (to reach a high peak bone mass), the optimization of the use of imaging techniques [dual-energy X-ray absorptiometry (DXA), vertebral fracture assessment (VFA) and new techniques measuring bone quality], the use of nonmedical treatment options and surgical techniques of fracture healing. In this review, we will discuss topics that play a role in the occurrence and prevention of fractures, and we give an overview of and insight into the critical issues and challenges around osteoporosis and fracture prevention.

Understanding Adolescent Low Back Pain From a Multidimensional Perspective: Implications for Management

Synopsis Low back pain (LBP) is the leading cause of disability worldwide. It often begins in adolescence, setting a course for later in life. We have tracked the course of LBP in the Raine Study cohort from the age of 14 years into early adulthood. Our work has found that LBP is already prevalent in individuals at 14 years of age and increases throughout adolescence and into early adulthood. It is often comorbid with other musculoskeletal pain. For some adolescents, LBP has little impact; for others, its impact includes care seeking, taking medication, taking time off from school and work, as well as modifying physical and functional activity. Of concern is the increasing prevalence of LBP with impact across adolescence, reaching adult rates by 22 years of age. The predictors of disabling LBP in adolescence are multidimensional. They include female sex, negative back pain beliefs, poor mental health status, somatic complaints, involvement in sports, and altered stress responses. Genetics also plays a role. Ironically, the factors that we have historically thought to be important predictors of LBP, such as "poor" spinal posture, scoliosis, carrying school bags, joint hypermobility, and poor back muscle endurance, are not strong predictors. This challenges our clinical beliefs and highlights that adolescent LBP needs a flexible and targeted multidimensional approach to assessment and management. In most cases, we recommend a cognitive functional approach that challenges negative LBP beliefs, educates adolescents regarding factors associated with their LBP, restores functional capacity where it is impaired, and encourages healthy lifestyle habits. J Orthop Sports Phys Ther 2017;47(10):741-751. Epub 12 Sep 2017. doi:10.2519/jospt.2017.7376.

The mediating role of the home environment in relation to parental educational level and preschool children's screen time: a cross-sectional study

Background

Previous studies suggest that preschoolers from low socioeconomic backgrounds engage in more screen time. Still, the factors in the social and physical home environment driving these differences in preschool children’s screen time are poorly understood. This study examines potential home environment mediators in the associations between parental educational level and preschoolers’ screen time.

Methods

A total of 864 children aged 3–6 years and their parents participated in a cross-sectional DAGIS study in 2015–2016. Parents recorded their children’s screen time in a diary (N = 823). For the analyses, the daily average screen time at home was calculated. Parental questionnaires (N = 808) assessed educational level and eight social and physical environment factors in the home (i.e., descriptive norm for children’s screen time, parental screen use in front of children, parental importance for limiting children’s screen time, parental attitude toward societal pressures for children’s screen time, access to screens at home, parental self-efficacy for limiting children’s screen time, satisfaction of children’s screen time, and rules for limiting children’s screen time). Parental education was grouped into low, middle, and high education. The associations were tested by conducting mediation analyses adjusted by season and children’s sex and age. The significant mediators in the single-mediator models were included in the final multiple-mediator models.

Results

Of the potential eight mediators, the following four had a significant indirect association: descriptive norm for children’s screen time, parental screen use in front of children, parental importance for limiting children’s screen time, and parental attitude toward societal pressures for children’s screen time. Parents with high education had lower descriptive norm and used fewer screens in front of children compared to parents with middle or low education, and in turn, these factors were associated with less screen time among children from parents with a higher education level. Parents with high education placed greater importance on limiting children’s screen time and felt less societal pressures about children’s screen time compared to parents with low education, and in turn, these factors were associated with less screen time among children from parents with a higher education level.

Conclusions

Our study recognized multiple modifiable mediators in the associations between parental education and preschool children’s screen time. When aiming to diminish socioeconomic status differences in preschool children’s screen time, the focus should be on parental role models, attitudes, and norm related to children’s screen time.

Sedentary behaviour and bone health in children, adolescents and young adults: a systematic review

Sedentary behaviour (SB) is increasing in Western societies and some studies suggest a deleterious effect of SB on bone. The aim of this systematic review was to examine the association between SB and bone health in children, adolescents and young adults. Electronic databases (PubMed, MEDLINE, PsycINFO and Science Citation Index) were searched for relevant articles up to January 9, 2017. Studies were included when results on bone health (e.g. strength, mass and structure) and either subjectively (questionnaires) or objectively (accelerometry) measured SB were reported in healthy participants ≤24 years. Two reviewers independently screened titles and abstracts for eligibility, rated methodological quality and extracted data. Seventeen observational studies were included. Several studies that used DXA or quantitative ultrasound suggested that objectively measured SB was negatively associated with lower extremity bone outcomes, such as femoral neck bone mineral density. The magnitude of this negative association was small and independent of moderate-to-vigorous physical activity. In contrast to the lower extremities, there was insufficient evidence for an association of lumbar spine bone outcomes with objectively measured SB. In high-quality studies that used DXA, no association was observed between objectively measured SB and total body bone outcomes. In studies using questionnaires, none of these relationships were observed. Well-designed longitudinal studies, objectively measuring SB, are needed to further unravel the effect of SB, physical activity and their interaction on bone health.

Tracking of vitamin D status from childhood to early adulthood and its association with peak bone mass

Background: To our knowledge, there are few longitudinal studies of vitamin D status from childhood to early adulthood, and it is uncertain whether vitamin D predicts peak bone mass in young adults.Objectives: The purpose of this longitudinal study was to evaluate the long-term stability of vitamin D status from ages 6 to 20 y in healthy individuals and to study associations between serum 25-hydroxyvitamin D [25(OH)D] at different developmental stages and bone mass measured at age 20 y.Design: Participants were offspring of the Western Australian Pregnancy Cohort (Raine) study. Serum 25(OH)D was assessed at ages 6, 14, 17, and 20 y, and whole-body bone mineral content (BMC) and bone mineral density (BMD) were measured at age 20 y through the use of dual-energy X-ray absorptiometry (DXA). Our analysis included 821 participants (385 females) who had ≥3 serum 25(OH)D measures and DXA data. We used latent class growth analysis and identified 4 vitamin D status trajectories: consistently lower (n = 259), decreasing (n = 125), increasing (n = 138), and consistently higher (n = 299).Results: There were significant correlations between serum 25(OH)D concentrations at different time points in both sexes (r = 0.346-0.560, P < 0.001), with stronger correlations at adjacent time points. In males, but not in females, serum 25(OH)D at ages 6, 17, and 20 y was positively associated with total-body BMC and BMD at age 20 y [covariate-adjusted increments of 40.7-53.9 g and 14.7-18.6 mg/cm², respectively, per 25 nmol/L 25(OH)D]; when 25(OH)D at all 4 ages was included in the same model, the concentration at age 6 y remained significant. Males in the "consistently higher" trajectory had 3.2-3.4% higher total body BMC and BMD than those who were in the "consistently lower" trajectory, accounting for age and anthropometric and lifestyle factors.Conclusions: Within both sexes, there are moderate associations between vitamin D status measured in prepuberty, adolescence, and early adulthood. Vitamin D status in childhood is a significant predictor of peak bone mass in male but not female subjects.