Insufficient and poor sleep patterns are common among adolescents worldwide. Up to now, the evidence on adolescent sleep has been mostly informed by country-specific studies that used different measures and age groups, making direct comparisons difficult. Cross-national data on adolescent sleep that could inform nations and international discussions are lacking. We examined the sleep patterns of adolescents across 24 countries and by gender, age, and affluence groups. Methods: We obtained sleep data on 165,793 adolescents (mean age 13.5 years; 50.5% girls) in 24 European and North American countries from the recent cross-sectional Health Behaviour in School-aged Children surveys (2013e2014 and 2017e2018). For each country, we calculated the age-standardized mean in sleep duration, timing, and consistency and the proportions meeting IMPLICATIONS AND CONTRIBUTION Conflicts of interest: The authors have no conflicts of interest to disclose. Disclosure: This supplement was supported by the World Health Organization European Office and the University of Glasgow. The articles have been peerreviewed and edited by the editorial staff of the Journal of Adolescent Health. The opinions or views expressed in this supplement are those of the authors and do not necessarily represent the official position of the funder.

Social media use is one of the most popular leisure activities among adolescents. Concomitant to this is a growing concern regarding problematic social media use and its relationship with health behaviors. To further increase the body of research into this phenomenon, our study explored the relationship between problematic social media use and physical activity levels, sleep peculiarities, and life satisfaction in Lithuanian children and adolescents. The study was conducted in April to June 2018 during the Health Behaviour in School-aged Children survey in Lithuania, a collaborative project of the World Health Organization. The sample comprised 4,191 school children (mean age 13.9 ± 1.69 years). The findings show that problematic social media use associates with about two times higher odds for worse sleep quality and lower life satisfaction. Problematic social media use was related to lower levels of vigorous physical activity in girls, but the possible effect on moderate physical activity was in boys and was inverse—boys with problematic social media use reported higher levels of moderate physical activity. Overall, in our study, girls with problematic social media use tended to have more negative health perceptions than boys. The results suggest that problematic social media use is an independent risk factor for negative health behaviors. This study adds to the accumulating knowledge that problematic social media use among adolescents may lead to worse health perceptions and, likely, further negative health outcomes.

Background: This study aims to explore how sufficient social support can act as a possible preventive factor against fighting and bullying in school-aged children in 9 European countries. Methods: Data for this study were collected during the 2013/2014 Health Behaviour in School-aged Children (HBSC) survey. The sample consisted of 9 European countries, involving 43,667 school children in total, aged 11, 13 and 15 years. The analysed data focus on social context (relations with family, peers, and school) as well as risk behaviours such as smoking, drunkenness, fighting and bullying in adolescents. The relationships between social support and violent behaviour variables were estimated using multiple regression models and multivariate analyses. Results: Bullying, across 9 countries, was more prevalent than fighting, except for Armenia, Israel, and Poland. The prevalence among countries differed considerably, with fighting being most expressed in Armenia and bullying—in Latvia and Lithuania. The strongest risk factors for bullying and fighting were male gender (less expressed for bullying), smoking and alcohol consumption. In addition, for bullying the social support was similarly strong factor like above-mentioned factors, while for fighting—less significant, but still independent. All forms of social support were significantly relate with lower violent behaviour of school children, and family support was associated most strongly. Regardless the socioeconomic, historical, and cultural differences among selected countries, the enhancement and reinforcement of the social support from possible many different resources should be taken into consideration in prevention programs against school violence behaviours.

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BackgroundInterleukin-10 and tumor necrosis factor α play an important role in breast carcinogenesis. Genes, encoding those two cytokines, contain single nucleotide polymorphisms, which are associated with differential levels of gene transcription. This study analyzes single nucleotide polymorphisms in interleukin 10 and tumor necrosis factor α genes and their contribution to breast cancer phenotype, lymph node status and survival in a group of young Lithuanian women with early-stage breast cancer patients.ResultsWe genotyped 100 premenopausal Eastern European (Lithuanian) patients with stage I-II breast cancer, ≤50 years old at the time of diagnosis, for interleukin 10 -592A > C, −819C > T and -1082A > G and tumor necrosis factor α -308G > A single nucleotide polymorphisms in the gene promoter region. We used the polymerase chain reaction, namely a restriction fragment length polymorphism method, for a SNP analysis. All genotypes were in Hardy-Weinberg equilibrium and had the same distribution as the HapMap CEU population. Holders of IL10 -592A > C heterozygous IL10 -592 AC genotype had a higher probability of estrogen receptor positive breast cancer phenotype than homozygous variants (P = 0.017). Phased ACC haplotype of IL10 polymorphisms was associated with younger age of diagnosis (P = 0.017). Of all the tested single nucleotide polymorphisms, only TNFα -308G > A has revealed a prognostic capability for breast cancer survival. GA genotype carriers, compared to GG, showed a significant disadvantage in progression-free survival (P = 0.005, adjusted hazard ratio (HR) = 4.631, 95 % confidence interval (CI) = 1.587 – 13.512), metastasis-free survival (P = 0.010, HR = 4.708, 95 % CI = 1.445 – 15.345) and overall survival (P = 0.037, HR = 4.829, 95 % CI = 1.098 – 21.243).ConclusionsAccording to our data, IL10 -1082A > G, −819 T > C, −592A > C polymorphisms and phased haplotypes have not revealed a prognostic value for breast cancer. On the contrary, the TNFα -308 polymorphism might modulate the risk and contribute to the identification of patients at a higher risk of breast cancer recurrence, metastasis and worse overall survival among young Lithuanian early-stage breast cancer patients.