Bullying at School, Cyberbullying, and Loneliness: National Representative Study of Adolescents in Denmark.

AIMS: The aim was to examine how loneliness was associated with bullying victimization at school and online. METHODS: We used data from the Danish arm of the international Health Behavior in School-aged Children (HBSC) study from 2022. The study population was a nationally representative sample of 11-15-year-olds who completed the internationally standardized HBSC questionnaire at school, n = 5382. Multilevel logistic regression was applied to study the associations between bullying victimization and loneliness. RESULTS: The prevalence of reporting loneliness often or very often was 9.0%; 6.3% of the sample experienced habitual bullying victimization at school, and 4.8% incurred cyberbullying. There was a strong and graded association between loneliness and bullying victimization at school and cyberbullying. The associations were significant for boys and girls, and the association between exposure to bullying at school and loneliness was steeper for boys than girls. The gradients were steeper for physical bullying than for cyberbullying. Students exposed to habitual bullying in both contexts had an adjusted OR (95% CI) of 11.21 (6.99-17.98) for loneliness. CONCLUSION: Exposure to bullying at school and cyberbullying are strongly associated with loneliness. It is important to reduce bullying at school and on the internet and to promote effective interventions to reduce continuing loneliness.

Loneliness and the risk of type 2 diabetes.

INTRODUCTION: The incidence of type 2 diabetes is increasing globally. Recent research suggests that loneliness could be a potential risk factor for the development of type 2 diabetes. We aimed to investigate the association between loneliness and type 2 diabetes and the modifying effect of mental disorders. RESEARCH DESIGN AND METHODS: We conducted a prospective study including 465 290 adults (aged ≥16 years) who participated in either the Danish Health and Morbidity Survey or the Danish National Health Survey between 2000 and 2017. Loneliness was based on self-report, while type 2 diabetes was measured using an algorithm combining several health registers including type 2 diabetes patients treated both within the hospital sector and general practice. Cox proportional hazards regressions were used to estimate hazard ratios (HRs) and 95% confidence intervals (95% CIs). RESULTS: During a mean follow-up time of 6.3 years, 13 771 individuals (3%) developed type 2 diabetes. Feeling lonely once in a while was associated with a 14% increased risk of type 2 diabetes (95% CI 1.09 to 1.20), while feeling lonely often was associated with a 24% increased risk (95% CI 1.14 to 1.34), independent of sociodemographic factors and body mass index. The association was stronger among individuals without a mental disorder (HR 1.21, 95% CI 1.10 to 1.34 among those feeling lonely often) compared with those with a mental disorder (HR 1.07, 95% CI 0.93 to 1.23). CONCLUSIONS: Loneliness independently increased the risk of type 2 diabetes. The effect was more pronounced in individuals without a mental disorder, as having a mental disorder itself likely increases the risk of type 2 diabetes. These findings emphasize the importance of addressing loneliness as a modifiable risk factor in preventing type 2 diabetes.

Trends in social inequality in breastfeeding duration in Denmark 2002-2019.

AIMS: The aim of the present study was to analyse trends in full breastfeeding for at least 4 months across socioeconomic position in Denmark over a 17-year-long period from 2002 to 2019 using parental education as the indicator of socioeconomic position. METHODS: The study used data on full breastfeeding collected between 2002 and 2019 by community health nurses in the collaboration Child Health Database, n=143,075. Data were linked with five categories of parental education from population registers. Social inequality was calculated as both the relative (odds ratio) and absolute social inequality (slope index of inequality). A trend test was conducted to assess changes in social inequality over time. RESULTS: A social gradient in full breastfeeding was found for the entire study period. The odds ratio for not being fully breastfed for at least 4 months ranged from 3.30 (95% confidence interval 2.83-3.84) to 5.09 (95% confidence interval 4.28-6.06) during the study period for infants of parents with the lowest level of education (primary school) compared with infants of parents with the highest level of education (5+ years of university education). The slope index of inequality was between -38.86 and -48.81 during the entire study period, P=0.80. This indicated that both the relative and absolute social inequality in full breastfeeding to at least 4 months of age was unchanged in the study period from 2002 to 2019. CONCLUSIONS: This study showed a persistent relative and absolute social inequality in full breastfeeding for at least 4 months from 2002 to 2019 in Denmark.

Recurrent headache, stomachache, and backpain among adolescents: association with exposure to bullying and parents' socioeconomic status.

OBJECTIVES: Recurrent pain is a prevalent and severe public health problem among adolescents and is associated with several negative health outcomes. In a representative sample of adolescents this study examined 1) whether exposure to bullying and low socioeconomic status (SES) were associated with recurrent headache, stomachache and backpain, 2) the combined effect of exposure to bullying and low SES on recurrent pain and 3) whether SES modified the association between bullying and recurrent pain. METHODS: Data derived from the Danish contribution to the international collaborative study Health Behaviour in School-aged Children (HBSC). The study population was students in three age groups, 11-, 13- and 15-year-olds from nationally representative samples of schools. We pooled participants from the surveys in 2010, 2014 and 2018, n=10,738. RESULTS: The prevalence of recurrent pain defined as pain 'more than once a week' was high: 11.7 % reported recurrent headache, 6.1 % stomachache, and 12.1 % backpain. The proportion who reported at least one of these pains 'almost every day' was 9.8 %. Pain was significantly associated with exposure to bullying at school and low parental SES. The adjusted odds ratio (AOR, 95 % CI) for recurrent headache when exposed to both bullying and low SES was 2.69 (1.75-4.10). Equivalent estimates for recurrent stomachache were 5.80 (3.69-9.12), for backpain 3.79 (2.58-5.55), and for any recurrent pain 4.81 (3.25-7.11). CONCLUSIONS: Recurrent pain increased with exposure to bullying in all socioeconomic strata. Students with double exposure, i.e., to bullying and low SES, had the highest OR for recurrent pain. SES did not modify the association between bullying and recurrent pain.

Circulating and Intratumoral Immune Determinants of Response to Atezolizumab plus Bevacizumab in Patients with Variant Histology or Sarcomatoid Renal Cell Carcinoma.

Renal cell carcinoma (RCC) of variant histology comprises approximately 20% of kidney cancer diagnoses, yet the optimal therapy for these patients and the factors that impact immunotherapy response remain largely unknown. To better understand the determinants of immunotherapy response in this population, we characterized blood- and tissue-based immune markers for patients with variant histology RCC, or any RCC histology with sarcomatoid differentiation, enrolled in a phase II clinical trial of atezolizumab and bevacizumab. Baseline circulating (plasma) inflammatory cytokines were highly correlated with one another, forming an "inflammatory module" that was increased in International Metastatic RCC Database Consortium poor-risk patients and was associated with worse progression-free survival (PFS; P = 0.028). At baseline, an elevated circulating vascular endothelial growth factor A (VEGF-A) level was associated with a lack of response (P = 0.03) and worse PFS (P = 0.021). However, a larger increase in on-treatment levels of circulating VEGF-A was associated with clinical benefit (P = 0.01) and improved overall survival (P = 0.0058). Among peripheral immune cell populations, an on-treatment decrease in circulating PD-L1+ T cells was associated with improved outcomes, with a reduction in CD4+PD-L1+ [HR, 0.62; 95% confidence interval (CI), 0.49-0.91; P = 0.016] and CD8+PD-L1+ T cells (HR, 0.59; 95% CI, 0.39-0.87; P = 0.009) correlated with improved PFS. Within the tumor itself, a higher percentage of terminally exhausted (PD-1+ and either TIM-3+ or LAG-3+) CD8+ T cells was associated with worse PFS (P = 0.028). Overall, these findings support the value of tumor and blood-based immune assessments in determining therapeutic benefit for patients with RCC receiving atezolizumab plus bevacizumab and provide a foundation for future biomarker studies for patients with variant histology RCC receiving immunotherapy-based combinations.

Adolescent loneliness across the world and its relation to school climate, national culture and academic performance.

BACKGROUND: Loneliness during adolescence has adverse consequences for mental health, education and employment outcomes. Yet, we know little about common correlates of loneliness among adolescents, making intervention work difficult. AIMS: In this study, we (1) explore individual-, school- and country-level correlates of loneliness to help identify potential intervention targets, and (2) examine the influence of loneliness on academic performance. SAMPLE: A total of 518,210 students aged 15 years from 75 countries provided self-reported loneliness data. RESULTS: Using multilevel modelling, we found individual-, school- and country-level correlates of self-reported school-based loneliness, and showed that loneliness negatively influenced academic performance. CONCLUSIONS: Based on the findings, interventions that focus on enhancing social and emotional skills, increasing trust between teachers and students and changing school climate to be more inclusive are likely to be the most effective for adolescents; they should also be culturally sensitive.

Preventing Stress among High School Students in Denmark through the Multicomponent Healthy High School Intervention-The Effectiveness at First Follow-Up.

Stress is a widespread phenomenon and young people especially are experiencing high levels of stress. School-related factors are the most frequently self-reported stressors among adolescents, but few interventions have targeted the school environment. This study evaluated the effectiveness of the Healthy High School (HHS) intervention on stress at a 9-month follow-up. The study included 5201 first-year high school students (~16 years) in Denmark. Participating schools were randomized into the HHS intervention (N = 15) or control group (N = 15). Baseline measurements were conducted in August 2016 and the follow-up was conducted in May 2017. The intervention was designed to promote well-being (primary outcome) by focusing on physical activity, meals, sleep, sense of security, and stress (secondary outcomes). The intervention comprised: structural initiatives at the school level; a teaching material; peer-led innovation workshops; and a smartphone app. The 10-item Perceived Stress Scale was used to measure stress. Intervention effects on perceived stress were estimated using an intention-to-treat approach with multiple imputations of missing data and multilevel general linear regression modelling. A total of 4577 students answered the baseline questionnaire. No statistically significant difference was found in stress between students at intervention and control schools at the follow-up (mean score: 16.7 versus 16.7, adjusted b = 0.42, 95% CI: -0.16;1.00). The HHS Study is one of the first large randomized controlled trials targeting school environmental stressors. Potential implementation failures and the failures of the program theory are discussed.

Binary outcomes of enhancer activity underlie stable random monoallelic expression.

Mitotically stable random monoallelic gene expression (RME) is documented for a small percentage of autosomal genes. We developed an in vivo genetic model to study the role of enhancers in RME using high-resolution single-cell analysis of natural killer (NK) cell receptor gene expression and enhancer deletions in the mouse germline. Enhancers of the RME NK receptor genes were accessible and enriched in H3K27ac on silent and active alleles alike in cells sorted according to allelic expression status, suggesting enhancer activation and gene expression status can be decoupled. In genes with multiple enhancers, enhancer deletion reduced gene expression frequency, in one instance converting the universally expressed gene encoding NKG2D into an RME gene, recapitulating all aspects of natural RME including mitotic stability of both the active and silent states. The results support the binary model of enhancer action, and suggest that RME is a consequence of general properties of gene regulation by enhancers rather than an RME-specific epigenetic program. Therefore, many and perhaps all genes may be subject to some degree of RME. Surprisingly, this was borne out by analysis of several genes that define different major hematopoietic lineages, that were previously thought to be universally expressed within those lineages: the genes encoding NKG2D, CD45, CD8α, and Thy-1. We propose that intrinsically probabilistic gene allele regulation is a general property of enhancer-controlled gene expression, with previously documented RME representing an extreme on a broad continuum.

Trends in Use of Alcohol and Cigarettes among Danish Adolescents, 2002-2018: Exclusive and Dual Use.

Many young adolescents experiment with substance use which can have substantial health implications later in life. This study examined trends in substance use among Danish adolescents from 2002 to 2018, including exclusive and dual current use of alcohol and cigarettes. Data on 13- and 15-year-olds (N = 15,295) from five comparable cross-sectional Health Behavior in School-aged Children (HBSC) surveys were used. Cochran-Armitage test for trend assessed the development in substance use patterns over time. Overall, a decreasing trend in current use of alcohol and cigarettes was found among Danish adolescents during the 16-year study period: from 71.7% in 2002 to 51.6% in 2018. In 2018, most adolescents (41.8%) currently used alcohol exclusively, 8.6% had a dual current use of cigarettes and alcohol, and 1.3% smoked cigarettes exclusively. Trends in alcohol use differed according to age groups, while no gender-specific trends in substance use were found. Findings suggest that a significant prevention potential in adolescent substance use remains, and future initiatives may focus on dual use of substances as well as tailored efforts to specific subgroups in high risk of using substances.

Effect of the multicomponent healthy high school intervention on meal frequency and eating habits among high school students in Denmark: a cluster randomized controlled trial.

BACKGROUND: Previous studies have shown that multicomponent interventions may improve meal frequency and eating habits in children, but evidence among young people is limited. This study evaluated the effect of the Healthy High School (HHS) intervention on daily intake of breakfast, lunch, water, fruit, and vegetables at 9-month follow-up. METHODS: The study included first-year students (≈16 years) attending high school in Denmark. Participating schools were randomized into the HHS intervention (N = 15) or control group (operating as usual) (N = 15). The intervention was designed to promote well-being (primary outcome) by focusing on healthy habits including meals, stress prevention, and strong peer relations. It included a curriculum, structural and organisational initiatives, a workshop, and a smartphone application. Students completed self-administered online questionnaires at the beginning of the school year and nine months later. To account for clustering of data, we used multilevel logistic regression analyses to estimate odds ratios (OR). We applied an intention-to-treat approach with multiple imputations of missing data. RESULTS: At baseline 4577 of 5201 students answered the questionnaire and 4512 at follow-up. In both groups the proportion of students eating breakfast decreased from approximately 50% to 40% from baseline to follow-up, and lunch frequency decreased from approximately 50% to 47%. Daily water intake, intake of fresh fruit and intake of vegetables remained unchanged from baseline to follow-up. There were no significant between group differences on any of the outcomes at first follow-up: breakfast: OR = 0.85 (95% CI: 0.65;1.10), lunch: OR = 0.96 (95% CI: 0.75;1.22), water intake: OR = 1.14 (95% CI: 0.92;1.40), intake of fresh fruit: (OR = 1.07, 95% CI: 0.84;1.37), vegetables: (OR = 1.01, 95% CI: 0.77;1.33). CONCLUSION: No evidence of an effect of the HHS intervention was found for any of the outcomes. Future studies are warranted to explore how health promoting interventions can be integrated in further education to support educational goals. Moreover, how to fit interventions to the lives and wishes of young people, by also including systems outside of the school setting. TRIAL REGISTRATION: ISRCTN, ISRCTN43284296 . Registered 28 April 2017 - retrospectively registered.

The Infant Health Study - Promoting mental health and healthy weight through sensitive parenting to infants with cognitive, emotional, and regulatory vulnerabilities: protocol for a stepped-wedge cluster-randomized trial and a process evaluation within municipality settings.

BACKGROUND: Child mental health problems are a major public health concern associated with poor mental and physical health later in development. The study evaluates a new community-based intervention to promote sensitive parenting and reduce enduring mental health problems and unhealthy weight among vulnerable infants aged 9-24 months. METHODS: We use a step-wedge cluster randomized controlled trial design conducted within a home visiting program offered by community health nurses to infant families in Denmark. Sixteen municipalities are randomly allocated to implement the intervention starting at three successive time points from May 1, 2022 to January 1, 2023. A total of 900-1000 families will be included. A standardized program, Psykisk Udvikling og Funktion (PUF), is used to identify infants with major problems of eating, sleep, emotional or behavioral regulation or developmental problems. The intervention builds on the Video-Feedback Intervention to Promote Positive Parenting (VIPP) program, adapted to the PUF-context and named the VIPP-PUF. Children will be followed up at ages 18 and 24 months. Primary outcome measure is the Strengths and Difficulties Questionnaire (SDQ) at child age 24 months. The other outcome measures include body mass index z-scores, the Ages and Stages Questionnaire Social-Emotional (ASQ:SE2); the Child Behavior Checklist (CBCL 1½ -5); Eating behavior Questionnaires; the Being a Mother-questionnaire (BaM13); the Parental Stress Scale (PSS); and the WHO-5 well-being index (WHO-5). Data on child and family factors are obtained from National registries and the Child Health Database. Quantitative measures are applied to examine the effectiveness of the VIPP-PUF intervention and the implementation process. Qualitative measures include interviews with CHNs, parents and municipality stakeholders to explore factors that may influence the adherence and effectiveness of the intervention. DISCUSSION: The study examines a service-setting based intervention building on the promotion of sensitive parenting to vulnerable infants. We use a mixed methods approach to evaluate the intervention, taking into account the influences of COVID-19 pandemic running since March 2020. Overall, the study has potential to add to the knowledge on the possibilities of prevention within the municipality child health care to reduce the risk of mental health problems and unhealthy weight in early childhood. TRIAL REGISTRATION: www.ClinicalTrials.gov ; ID NCT04601779 ; Protocol ID 95-110-21307. Registered 25 June 2021.

Chronic backpain among adolescents in Denmark: trends 1991-2018 and association with socioeconomic status.

Chronic backpain among adolescents is important because the prevalence is high, above 10%, and more than 10% of all adolescents experience impacts on important day-to-day activities. Chronic backpain tracks into adulthood and is associated with several health problems. The objective was to study trends in the prevalence of chronic backpain among adolescents 1991-2018, to examine the association with socioeconomic status (SES), and whether this association changed over time. The study used data from eight comparable cross-sectional school surveys of nationally representative samples of 11-15-year-olds in 1991, 1994, 1998, 2002, 2006, 2010, 2014, and 2018, which constitute the Danish arm of the international Health Behaviour in School-aged Children (HBSC) study. The participation rate was 74.6% of the eligible study population, n = 29,952. Chronic backpain was defined as self-reported backpain daily or several days a week during the last 6 months. The prevalence of chronic backpain was 11.1%, significantly increasing from 8.9% in 1991 to 11.7% in 2018. The OR for chronic backpain was 1.20 (95% CI: 1.10-1.31) in middle, and 1.56 (95% CI: 1.41-1.73) in low compared to high SES. Sensitivity analyses with two other cut-points for backpain frequency showed similar associations.Conclusion: Chronic backpain is common among adolescents and the prevalence increased from 1991 to 2018. The prevalence was highest in lower SES families. We recommend increased efforts to prevent chronic backpain. What is Known: • Chronic backpain among adolescents is common, has a high burden of disability, is associated with several health problems, and tracks into adulthood. What is New: • The prevalence of chronic backpain among adolescents in Denmark increased from 8.9% in 1991 to 11.7% in 2018. • The prevalence was highest among adolescents from lower SES families.

Peer mentors' role in school-based health promotion: qualitative findings from the Young & Active study.

Peer-led interventions are highlighted as promising strategies to promote health among adolescents, but little is known about the mechanisms underlying this approach. To better understand the role of peer mentors (PMs) as implementers in school-based health promotion, we combined participant observations, focus group interviews and video recordings to explore high school students' reception of a peer-led intervention component (Young & Active). Young & Active aimed to increase well-being among first-year high school students (∼16 years of age) through the promotion of movement and sense of community and was implemented during the school year 2016-2017 in a larger school-based intervention study, the Healthy High School study in Denmark. The Healthy High School study was designed as a cluster-randomized controlled trial with 15 intervention schools and 15 control schools. At each intervention school, university students in Sports Science and Health (members of the research group) facilitated an innovation workshop aiming at inspiring all first-year students to initiate movement activities at schools. The findings illustrate potentials and challenges implied in the PM role. The peer mentors' profound commitment, as well as their response and sensibility to situational contingencies, were found to be significant for the students' reception and experience of the intervention. In conclusion, the specific job of PMs as implementers seems to consist of simultaneously following a manual and situationally adjusting in an emerging context balancing commitment and identification to the target group and the intervention project.

Peer-delivery of health promotion is highlighted as a promising strategy to reach adolescents, but little is known about the mechanisms underlying this approach. To better understand the role of peer mentors (PMs) as implementers, we used qualitative methods to explore high school students' reception of a peer-led workshop (Young & Active) in a school-based intervention in Denmark. Young & Active aimed to increase well-being among first-year high school students (∼16 years of age) through the promotion of movement and sense of community and was implemented during the school year 2016­2017. At each intervention school, university students in Sports Science and Health facilitated an innovation workshop to inspire all first-year students to initiate movement activities at schools. We found different potentials and challenges implied in the PM approach. Balancing peer mentors' commitment and identification to the recipients and the intervention seems central.

Underweight among adolescents in Denmark: prevalence, trends (1998-2018), and association of underweight with socioeconomic status.

BACKGROUND: Underweight among adolescents is an important clinical and public health issue. It is associated with adverse health outcomes throughout the life-span and may reflect food poverty, unhealthy eating habits, or some underlying health conditions. OBJECTIVE: To study prevalence and trends in underweight among adolescents 1998-2018, to examine social inequality in underweight, and whether social inequality changed over time. METHODS: Data were derived from 6 cross-sectional school surveys from The Health Behaviour in School-aged Children study in Denmark. The study included 11-, 13-, and 15-year-old schoolchildren in random samples of schools in 1998, 2002, 2006, 2010, 2014, and 2018 (n = 22,177). Underweight was determined by body mass index-for-age thinness grade 2-3 (the Cole and Lobstein method). Socioeconomic status was determined using occupational social class (the Danish OSC Measurement). RESULTS: The overall prevalence of underweight was 3.1% among boys and 5.3% among girls (P < 0.0001) and decreased by age (P < 0.0001) among both boys and girls. The prevalence of underweight was almost stable from 1998 to 2018. There was no observed absolute or relative social inequality in the prevalence of underweight among boys or girls. CONCLUSION: The prevalence of underweight in 11- to 15-year-olds was significantly higher among girls than boys. The prevalence remained stable from 1998 to 2018. There was no significant association between SES and prevalence of underweight. It is important to elucidate the underlying causes of underweight such as malnutrition, eating disorders, eating problems, loss of appetite, chronic diseases, insufficient knowledge of nutrients effects on bodily functions, and persistent pain.

Underweight among adolescents is an important clinical and public health issue as it may reflect food poverty, unhealthy eating habits, or some underlying health problem. The aim was to study prevalence and trends in underweight among adolescents 1998­2018 and to examine social inequality in underweight. We used data from 6 cross-sectional school surveys from Denmark. Across all surveys, the number of participants was 22,177 11-, 13-, and 15-year-old students. The prevalence of thinness grades 2 and 3 were taken as indicators of underweight and were 3.1% among boys and 5.3% among girls. This prevalence was almost stable from 1998 to 2018. Contrary to overweight, which is usually more prevalent in lower socioeconomic groups, underweight was not associated with socioeconomic status. There were 2 exceptions: the prevalence of underweight among girls was highest in those from high socioeconomic groups in1998, while the prevalence among boys was highest in those from low socioeconomic groups in 2018. Underweight conditions in adolescents need careful medical examinations to elucidate the underlying causes of underweight, for example, malnutrition, eating disorders, eating problems, loss of appetite, voluntary uptake of fad diets, chronic disease, insufficient knowledge of nutrients that impact their bodily functions, mental health problems, and persistent pain.

Lonely, but Not Alone: Qualitative Study among Immigrant and Native-Born Adolescents.

This paper explores loneliness as it is understood and experienced by adolescents, with a special focus on the importance of their migration status. We recruited students from five schools following a maximum variation sampling scheme, and we conducted 15 semi-structured, individual interviews with eighth-grade adolescents (aged 14-15 years) that were immigrants, descendants, and with a Danish majority background. A thematic analysis was applied with a special focus on differences and similarities in understanding and experiencing loneliness between adolescents with diverse migration status. The results showed more similarities than differences in loneliness. Generally, loneliness was described as an adverse feeling, varying in intensity and duration, and participants referenced distressing emotions. Feeling lonely was distinguished from being alone and characterized as an invisible social stigma. A variety of perceived social deficiencies were emphasized as causing loneliness, emerging in the interrelation between characteristics of the individual and their social context. The results add to the current literature by highlighting that it is not the presence of specific individual characteristics that causes loneliness; instead, loneliness is dependent on the social contexts the individual is embedded in. Differences across migration status were few and related to variations in the adolescents' individual characteristics. The findings highlight the importance of (1) studying the characteristics of both the individual and the social context in research on the antecedents to adolescents' loneliness, and (2) applying this perspective in other studies on the importance of migration status.

Coordinated maintenance of H3K36/K27 methylation by histone demethylases preserves germ cell identity and immortality.

Germ cells have evolved unique mechanisms to ensure the transmission of genetically and nongenetically encoded information, whose alteration compromises germ cell immortality. Chromatin factors play fundamental roles in these mechanisms. H3K36 and H3K27 methyltransferases shape and propagate a pattern of histone methylation essential for C. elegans germ cell maintenance, but the role of respective histone demethylases remains unexplored. Here, we show that jmjd-5 regulates H3K36me2 and H3K27me3 levels, preserves germline immortality, and protects germ cell identity by controlling gene expression. The transcriptional and biological effects of jmjd-5 loss can be hindered by the removal of H3K27demethylases, indicating that H3K36/K27 demethylases act in a transcriptional framework and promote the balance between H3K36 and H3K27 methylation required for germ cell immortality. Furthermore, we find that in wild-type, but not in jmjd-5 mutants, alterations of H3K36 methylation and transcription occur at high temperature, suggesting a role for jmjd-5 in adaptation to environmental changes.

What characterizes schools and students participating in health promoting school-based intervention studies? Findings from the healthy high school study.

The Healthy High School (HHS) intervention was developed to promote well-being among first-year high school students (~16 years of age) in Denmark by targeting stress, physical activity, meal habits, sleep, and sense of community. Thirty-one schools were randomly allocated to intervention (16 schools) or control (15 schools) groups in a cluster-randomized controlled trial. The purpose of this short communication was to compare characteristics of students and schools between 1) schools accepting to participate in the HHS study and non-participating schools using national survey data and 2) intervention and control schools using HHS baseline data. We included cross-sectional data from the Danish National Youth Study 2014 on 119 schools and 22,935 first-year students to characterize participating schools and students. At baseline (August 2016), students (n = 4577; 88.0%) and principals (n = 29; 96.7%) completed online questionnaires. Compared to non-participating schools, fewer HHS schools perceived their school as being popular and offered weekly sport activities outside school hours. More HHS schools had teachers engaged in health promotion activities and focused on stress prevention. The characteristics of HHS students did not differ markedly from non-participating high school students. There were no socio-demographic, outcome or contextual differences between the study arms. To ensure successful recruitment of schools it is important that the intervention meets the need of the schools and that the advantages of participation are explicit. This underlines the need for a thorough needs assessment prior to intervention development, co-creation of intervention activities with school staff, and a well-planned recruitment strategy.