Associations between adolescents' energy drink consumption frequency and several negative health indicators.

BACKGROUND: The purpose of this study was to identify how various negative health indicators are associated with energy drink consumption frequency among 13- and 15-year-old Finnish adolescents. METHODS: Data (N = 2429) from the nationally representative international Health Behaviour in School-aged Children study (2018) were analyzed via descriptive analysis and logistic regression analyses, with control for salient covariates. Relative risks (RR) were derived from the adjusted odds ratios. RESULTS: Even infrequent energy drink consumption was associated with various negative health indicators. Moreover, as compared to non-users, frequent energy drink consumers were more likely to report several health-compromising behaviors: current smoking (RR = 9.85, 95% CI: 5.68-16.02), current snus use (RR = 3.62, 95% CI: 1.80-6.85), cannabis use (RR = 3.42, 95% CI: 1.69-6.52), alcohol consumption (RR = 3.08, 95% CI: 2.49-3.71), problematic social media use (RR = 2.53, 95% CI:1.68-3.72), short sleep (RR = 2.12, 95% CI: 1.69-2.60), skipping breakfast (RR = 1.87, 95% CI: 1.51-2.29), drunkenness (RR = 1.59, 95% CI: 1.11-2.23), inadequate tooth brushing (RR = 1.28, 95% CI: 1.05-1.54). In addition, frequent energy drink consumption was associated with perceived negative health indicators: feelings of insufficient sleep (RR = 1.56, 95% CI: 1.11-2.15), low self-rated health (RR = 1.48, 95% CI: 1.15-1.87), and multiple health complaints (RR = 1.31, 95% CI: 1.07-1.56). CONCLUSIONS: Energy drink consumption, even infrequent, was associated with several negative health indicators, and the reporting of these increased with the frequency of energy drink consumption. The findings support the concerns of health authorities regarding the negative associations between energy drink consumption and health, even among persons as young as 13 years. There is evidence to support specific policy level actions, including restrictions on the sale of energy drinks to adolescents. This measure has been proposed in a Finnish government program, but implementation has yet to occur. Moreover, marketing of these beverages in platforms that are popular among adolescents (e.g., the social media) should be rigorously evaluated, and comprehensive interventions and actions implemented to ensure that adolescents, parents/guardians, and professionals working with adolescents (e.g., in schools) have a good understanding of the links between energy drink consumption and health.

Loneliness, subjective health complaints, and medicine use among Finnish adolescents 2006-2018.

AIMS: Loneliness is an important public health challenge for all ages. This study reports time trends of loneliness among adolescents over a 12-year period and analyses the strength of the associations between loneliness, health complaints, and medicine use. METHODS: Data were derived from the cross-sectional Finnish Health Behaviour in School-aged Children study conducted in 2006, 2010, 2014, and 2018. The study population is based on a random sample of schools with 20,444 participants aged 11-15 years. The trends were analysed with a Mantel-Haenszel test, and the strength of the associations was evaluated by mixed-effects logistic and linear regressions. RESULTS: An increasing prevalence in frequent loneliness (2006: 11%; 2018: 15%) was evident over the 12-year study period, especially in girls and 15-year-olds. Among all adolescents, loneliness was associated with a higher risk of recurrent health complaints and medicine use to treat the corresponding health issues, especially nervousness (odds ratio 5.8) and sleeping difficulties (odds ratio 7.6). CONCLUSIONS: Adolescence is a period of higher risk of frequent loneliness and associated health complaints. In this study, loneliness was common among adolescence and an increasing trend of loneliness was observed between 2006 and 2018. Also, psychosomatic health complaints and medicine use were strongly associated with loneliness. Persistent loneliness is a significant health risk and failure to resolve loneliness before entering adulthood may imply significant concerns for future well-being.

Does health literacy explain regional health disparities among adolescents in Finland?

Health literacy (HL)-as a broad range of health-related competencies-has been proposed to be a promising construct in understanding health disparities better, also among adolescents. Several factors have been found to explain differences in adolescents' HL levels; however, not much is known about how different regions of a country or majority/minority status is associated with HL, or whether HL is associated with regional health disparities. The aim of this study was to examine and compare HL and health levels among majority- and minority-language-speaking adolescents living in different regions of Finland, and to explore if HL explains regional health disparities, taking into account other important structural stratifying factors. The study uses Health Behaviour in School-aged Children survey data, collected among 13- and 15-year-old pupils in Finnish- and Swedish-speaking schools in Finland in 2014 (N = 3853/1123; 85/83%). Findings suggest that regional differences in HL levels and regional health disparities exist in both language groups. Health disparities were present in the Finnish-speaking sample among boys, the proportion rating their health as excellent ranging from 23 to 31% across regions, and in the Swedish-speaking sample among girls, the corresponding numbers ranging from 13 to 20%. In addition to other important structural stratifying factors, comprehensive HL explains these regional health disparities. This study adds to prior studies on the role of HL as a modifiable health resource by showing that regional health disparities among adolescents can partially be attributed to corresponding HL differences.

Empowerment-enabling home and school environments and self-rated health among Finnish adolescents.

Perceived health during adolescence has not only immediate consequences for individuals and for society, but also long-term. We need to understand better the health development in this period of the lifespan. Empowerment may be one pathway through which social factors and conditions translate into health effects. This study aimed to examine whether empowerment-enabling home and school environments are associated with self-rated health among adolescents, and whether the associations differ between genders, age or majority/minority language groups. Anonymous questionnaire data from respondents aged 11, 13 and 15 years were obtained from the Health Behaviour in School-aged Children study, conducted in Finland in 2014 in Finnish- and Swedish-speaking schools (n = 5925/1877). The proportion rating their health as excellent varied between 33.6 (11-year-olds) and 23.1% (15-year-olds), boys rating their health as excellent more often than girls in all age groups. Findings showed that indicators of both empowerment-enabling home and school environments were independently and positively related to adolescents' self-rated health. Whereas a respectful, accepting, kind and helpful attitude among classmates and a good home atmosphere were quite consistently associated with excellent health, there were gender and age differences with concern to the other empowerment-enabling indicators. Moreover, there were gender-, age- and language-related differences regarding adolescents' perceptions of how empowerment enabling their environments were. Home and school environments that create opportunities through encouragement and care, and through strengthening feelings of being secure, accepted and respected are potentially empowerment enabling. This study suggests that such environmental qualities are important for the perceived health of young people.

Leisure-time physical activity and participation in organized sports: Changes from 1985 to 2014 in Finland and Norway.

Participation in organized sports is a popular and important part of the lives of children and adolescents and is associated with improved psychological and social health, as well as an increased likelihood of meeting physical activity (PA) recommendations. Changes in modern society, including increased car ownership and use of technology and electronic media, have led to an additional focus on the importance of health-enhancing PA among children and adolescents. The aim of this article was to study the secular changes in self-reports of participation in organized sports clubs and leisure-time vigorous physical activity (LVPA), and whether the relationship between participation in organized sports clubs and LVPA has changed from 1985 to 2014. Questionnaire data were collected in two cross-sectional samples of Finnish and Norwegian 11-, 13- and 15-year-olds in 1985/1986 (n = 7137) and 2014 (n = 9218). Overall, participation in organized sports clubs and level of LVPA appears to have changed in the same direction in the two Nordic countries. The proportion of 11-year-olds reporting to be participants in organized sports clubs increased from 1985/1986 to 2014. There was an overall increase in self-reported LVPA. The association between participation in sports clubs and LVPA was stronger in 2014 than in 1985/1986. The findings indicated subgroup differences, in particular with regard to a steeper increase in LVPA and participation in sports clubs among Finnish girls. We suggest that attention should be given to the role of organized sports to better understand secular changes in PA.

Does health literacy explain the link between structural stratifiers and adolescent health?

BACKGROUND: The concept of health literacy (HL) may help us to better understand the mechanisms leading to health disparities, and to focus on the factors that can be influenced. However, not much is yet known about how HL is related to health disparities, or whether the association exists among adolescents. The aim of the study was to examine the associations between structural stratifiers, HL and health indicators among adolescents. METHODS: The nationally representative Finnish Health Behaviour in School-aged Children survey data (n=3833) were collected from 13- and 15-year-old pupils in the spring of 2014. Pearson correlation coefficients were calculated, and separate path models were estimated for the perceived health and health behaviour measures. RESULTS: HL was found to be an independent factor explaining disparities in health. Higher HL was related to positive health outcomes. HL also acted as a mediator between health behaviours and structural stratifiers, except for gender. School achievement and educational aspirations were among the factors explaining the HL level, which in turn, explained the health indicators. CONCLUSION: The concept of HL is of use in understanding health disparities. In particular, HL provides a mechanism via which school achievement and educational plans affect health outcomes. Low HL places adolescents who have poor school achievement and who do not intend to continue on an academic path in an unequal position with respect to their health.

Loneliness and subjective health complaints among school-aged children.

AIM: The first aim of this study was to explore the prevalence of loneliness and subjective health complaints (SHCs) among school-aged children in Finland. The second aim was to analyse to what extent perceived loneliness explains any variance in SHCs among school-aged children. METHOD: A representative sample of 5925 Finnish children and adolescents from grades 5 ( Mage=11.8 years), 7 ( Mage=13.8) and 9 ( Mage=15.8) completed the Health Behaviour in School-aged Children (HBSC) survey. Descriptive statistics were used to examine the prevalence of health complaints and loneliness. Structural equation modelling was used to test how strongly loneliness was associated with SHCs. RESULTS: The prevalence of loneliness and SHCs was higher among girls and increased with age. Loneliness was a significant predictor of health complaints, especially of psychological symptoms among girls and among ninth grade students. CONCLUSIONS: The findings indicate that loneliness is a major risk to the health and well-being of school-aged children. The strong association between loneliness and SHCs highlights the importance of active preventive actions to reduce loneliness.

Socioeconomic differences in the use of alcohol and drunkenness in adolescents: Trends in the Health Behaviour in School-aged Children study in Finland 1990-2014.

AIMS: The aims of this study were to explore time-based trends of socioeconomic differences in alcohol use and drunkenness in Finnish adolescents from 1990 to 2014 and to investigate the significance of two indicators in detecting socioeconomic differences in alcohol use and drunkenness. METHODS: Data were retrieved from seven surveys conducted as part of the Health Behaviour in School-aged Children (HBSC) study in Finland from 1990 to 2014. The alcohol use and drunkenness of 15-year-old students, as well as socioeconomic status, including educational aspiration and perceived family wealth, were assessed via a self-report questionnaire. Logistic regression models were used to investigate the relationships between alcohol use, drunkenness and indicators of socioeconomic status. RESULTS: The study showed that the alcohol use and drunkenness of Finnish 15-year-old adolescents have decreased since the late 1990s. However, the level of decrease is not consistent among different socioeconomic groups and socioeconomic differences in drinking behaviour between two educational aspiration groups have persisted over two decades. Girls from the groups with low perceived family wealth were more likely to be frequently drunk in the time period 2006-2014. CONCLUSIONS: This study suggests that students with low educational aspiration should be the target population for interventions aiming at reducing the alcohol use and drunkenness of Finnish adolescents. In future interventions aimed at reducing heavier drinking, adolescents (especially girls) from less wealthy families should be the first priority. Further studies on trends in socioeconomic differences in alcohol use and drunkenness in adolescence should be conducted using different indicators of socioeconomic status and other social context factors should also be taken into account.

Health literacy and participation in sports club activities among adolescents.

AIMS: The aim of this research was to compare the levels of perceived health literacy among adolescents who do or do not participate in sports club activities. Organized sport club activities reach a high proportion of adolescents, and have the potential to contribute to the development of their health literacy. METHODS: The cross-sectional data on health literacy among school children in Finland (aged 13 and 15, n=3852) were measured, as a part of the Health Behaviour in School-Aged Children (HBSC) study, using the Health Literacy for School-aged Children (HLSAC) instrument. Sports club participation and its association with health literacy were examined in relation to age, gender, family affluence, school achievement, and physical activity. The statistical analyses included cross-tabulation and the multilevel mixed-effects logistic regression analyses. RESULTS: Perceived health literacy was higher among adolescents who participated in sports club activities. This conclusion was valid for boys and girls, for both age groups, among those who were physically active 6-7 days a week, had at least moderate school achievement, and those who belonged to the middle or high affluence families. From the health literacy perspective, participation in sports club activities was especially beneficial for those having low or moderate school achievement level. CONCLUSIONS: The sports club setting may work towards equalizing health literacy differences related to school achievement. However, the clubs should ensure that access is available to as many adolescents as possible; by this means they may spread beneficial influences, supporting the development of health literacy among broader population groups.

Physical Activity Among Adolescents With Long-Term Illnesses or Disabilities in 15 European Countries.

Physical activity (PA) is an important health-promoting behavior from which adolescents with long-term illnesses or disabilities (LTID) can benefit. It is important to monitor differences across countries in adherence with PA recommendations for health. The aim of this study was to compare PA levels among 15 European countries after disaggregating data by disability. Data from pupils (mean age = 13.6 years, SD = 1.64) participating in the 2013/2014 Health Behavior in School-aged Children study were analyzed to compare adolescents without LTID, with LTID, and with LTID that affects their participation (affected LTID). Logistic regression models adjusted for age and family affluence, stratified by gender and country group with PA recommendations for health as the outcome variable. With the data pooled, 15% (n = 9,372) of adolescents reported having LTID and 4% (n = 2,566) having affected LTID. Overall, fewer boys with LTID met PA recommendations for health than boys without LTID, although it was not statistically significant either at the national levels or for girls.

Socioeconomic differences in adolescents' smoking: a comparison between Finland and Beijing, China.

BACKGROUND: Various studies have demonstrated the associations between socioeconomic status (SES) and health and health behaviour among adolescents. However, few studies have compared the socioeconomic difference in adolescent smoking between countries with different stage of smoking. The purpose of this study was to examine and compare the relationship between socioeconomic status (SES) and adolescent smoking in Beijing, China and Finland through the Health Behaviour in School-aged Children (HBSC) study. METHODS: The data used in this study were derived from the Chinese HBSC linked project survey 2008 in Beijing and the Finnish HBSC survey 2006. The final sample included 2005 Chinese and 1685 Finnish 15-year-old schoolchildren. The associations between Family Affluence Scale (FAS), as the SES measure, and adolescents' smoking behaviour, including ever smoked, weekly smoking and the early onset of smoking were examined separately in two countries through binary logistic regression. RESULTS: Compared to students from the high FAS group, Chinese boys from the low FAS group were more likely to report having ever smoked (OR = 2.12, 95 % CI = 1.49-3.01) and being early onset of smoking (OR = 2.17, 95 % CI = 1.44-3.26). Finnish girls from the low FAS group were more likely to report being weekly smokers (OR = 1.68, 95 % CI = 1.07-2.65). No significant difference was found for Chinese girls and Finnish boys. CONCLUSIONS: This study indicated different patterns of socioeconomic difference in smoking between Chinese and Finnish adolescents by gender and by smoking behaviour, which suggests that socioeconomic inequalities in smoking are different among adolescents in countries with different stage of smoking. Country specific policies and interventions for different target groups should be encouraged and designed for reducing the prevalence of adolescents' smoking.

Trends in self-reported sleep problems, tiredness and related school performance among Finnish adolescents from 1984 to 2011.

The aim of this study was to investigate long-term trends in insomnia symptoms, tiredness and school performance among Finnish adolescents. A time-series from 1984 to 2011 was analysed from two large-scale survey studies, the Finnish School Health Promotion Study and the Health Behavior in School-Aged Children study. A total of 1,136,583 adolescents aged 11-18 years answered a standardized questionnaire assessing frequency of insomnia symptoms, tiredness and school performance. A clear approximately twofold increasing trend in insomnia symptoms and tiredness was found from the mid-1990s to the end of the 2000s. The increase was evident in all participating age groups and in both genders. After 2008, the increase seems to have stopped. Insomnia symptoms and tiredness were associated with lower school performance and they were more prevalent among girls (11.9 and 18.4%) compared to boys (6.9 and 9.0%, respectively). Unexpectedly, we also observed an increasingly widening gap in school performance between normally vigilant and chronically tired pupils. The underlying causes of these phenomena are unknown, but may concern changes in the broader society. The observed recent increasing trend in adolescents' sleep problems is worrisome: poor sleep quality has also been suggested to associate with clinical or subclinical mood or anxiety disorders and behavioural problems and predispose to sleep and psychiatric disorders later in life. Our results justify further studies and call for serious attention to be paid to adolescent's sleep in the Finnish educational system and society at large.

Secular trends in moderate-to-vigorous physical activity in 32 countries from 2002 to 2010: a cross-national perspective.

BACKGROUND: Sufficient levels of moderate to vigorous physical activity (MVPA) give substantial health benefits to adolescents. This article examines trends in physical activity (PA) from 2002 to 2010 across 32 countries from Europe and North America. METHODS: Representative samples included 479 674 pupils (49% boys) aged 11 years (n = 156 383), 13 years (n = 163 729) and 15 years (n = 159 562). The trends in meeting the recommendations for PA (at least 60 min daily) were evaluated using logistic regression. RESULTS: There was a slight overall increase between 2002 and 2010 (17.0% and 18.6%, respectively). MVPA increased significantly (P ≤ 0.05) among boys in 16 countries. Conversely, nine countries showed a significant decrease. Among girls, 10 countries showed a significant increase (P ≤ 0.05). Eight countries showed a significant decrease. For all countries combined, girls were slightly less likely to show an increase in PA over time. CONCLUSIONS: The majority of adolescents do not meet current recommendations of PA. Further investment at national and international levels is therefore necessary to increase PA participation among children and adolescents and reduce the future health burden associated with inactivity.

Adolescent use of social media and associations with sleep patterns across 18 European and North American countries.

OBJECTIVE: Over the past decade, concurrent with increasing social media use (SMU), there has been a shift toward poorer sleep among adolescents in many countries. The purpose of this study was to examine the cross-national associations between adolescent SMU and sleep patterns, by comparing 4 different categories of SMU (nonactive, active, intense, and problematic use). DESIGN, SETTING, AND PARTICIPANTS: Data were from 86,542 adolescents in 18 European and North American countries that participated in the 2017/18 Health Behaviour in School-aged study. MEASUREMENTS: Mixed-effects linear regression models were used to examine cross-national associations between 4 SMU categories and adolescent sleep duration, bedtime and social jetlag derived from self-reported data. RESULTS: For all countries combined, nonactive SMU was associated with longer sleep, earlier bedtimes, and less social jetlag, compared to active SMU, although the differences were minor. By comparison, intense and problematic SMU were associated with less sleep and later bedtimes on both school and nonschool days, and greater social jetlag, compared to active SMU. While findings were relatively consistent between countries, some differences were observed, suggesting that the national and cultural context may be important in interpreting results. CONCLUSIONS: These findings suggest that both intense and problematic SMU are associated with poorer sleep patterns in adolescents across most countries. Further research is needed to identify effective policies, programs, and messaging to promote the healthy use of social media and prevent potential negative impacts on adolescent sleep.

Is physical activity associated with low-risk health behaviours among 15-year-old adolescents in Finland?

AIMS: To investigate the associations between physical activity and the pattern of risk health behaviour consisting of smoking, alcohol consumption, snuff (snus), cannabis, and condom use among 15-year-old adolescents, taking their educational aspirations and family affluence into account. METHODS: The data were collected in the Health Behaviour in School-aged Children (HBSC) study in Finland in 2006. Standardised questionnaires were issued at schools to a 15-year-old nationally representative sample, of which 84.5% (1710 pupils) participated. Logistic regression analysis was used to explore the associations between physical activity, pattern of risk health behaviour, family affluence, and educational aspirations. Separate models for daily moderate-to-vigorous physical activity (MVPA) and leisure-time physical activity (LTPA) were tested. Multi-level analysis was performed in order to control the nested characteristics of the data. RESULTS: Boys were significantly more physically active and used alcohol, cannabis, and snuff more often than girls. Girls had used a condom in their last intercourse less often than boys. The educational aspirations for higher education had the strongest association with the low-risk health behaviour, with the odds ratios in the MVPA model 3.30 (95% CI 2.41-4.55) for the boys and 3.46 (95% CI 2.56-4.67) for the girls. In the LTPA model, the corresponding odds ratios were 3.31 (95% CI 2.40-4.56) for the boys and 3.52 (95% CI 2.60-4.56) for the girls. CONCLUSIONS: Physical activity was not significantly associated with the low-risk health behaviour, whereas educational aspirations for higher education showed the strongest association. The results support the earlier studies indicating a social gradient in health-related behaviour already in adolescence.

The medicine use and corresponding subjective health complaints among adolescents, a cross-national survey.

BACKGROUND: Medicine use among children and young people is under-researched. Studies that investigated cross-national patterns in adolescents' medicine use practice are rare. This study aims to investigate adolescents' medicine use for corresponding health complaints in Europe and USA. METHODS: Nationally representative samples of adolescents from 19 countries and regions in Europe and USA completed an anonymous, standardised questionnaire as part of the Health Behaviour in School-aged Children 2005/2006 survey. The prevalence of health complaints and medicine use were determined. The influence of the frequency of medicine use, age, gender and country of residence, on the likelihood of medicine use was assessed using multilevel multivariate logistic regression, with separate analyses for boys and girls. RESULTS: Both health complaints and medicine use were common among adolescents. Medicine use was strongly associated with the frequency of health complaints. The prevalence of both medicine use and health complaints was higher among girls than boys. Boys and girls with weekly health complaints were both similarly likely to report elevated rates of medicine use. CONCLUSIONS: The findings indicated that adolescents who report more frequent recurrent health complaints are also more likely to report more frequent medicine use for their health complaints. Adolescent boys with weekly health complaints have the same risk of medicine use as girls with weekly health complaints. The importance of educating school-aged children to interpret their bodily feelings and complaints and to use medicines appropriately is of high priority.

Energy Drink Consumption Among Finnish Adolescents: Prevalence, Associated Background Factors, Individual Resources, and Family Factors.

Objectives: Energy drink consumption among adolescents has become a notable global phenomenon, and has been associated with numerous negative health outcomes. In order to understand the popularity of energy drinks among adolescents, and to target interventions, it is important to identify the determinants underpinning consumption. Methods: The nationally representative data (cross-sectional) were drawn from the Health Behaviour in School-aged Children (HBSC) surveys, conducted in 2014 and 2018, each comprising 13- and 15-year-old Finnish adolescents (n = 7405). Results: Weekly energy drink consumption increased among Finnish adolescents between 2014 (18.2%) and 2018 (24.4%), especially among girls. In 2018, boys typically consumed more than girls, and 15-year-olds more than 13-year-olds. Moreover, in 2018, weekly energy drink consumption was more prevalent among 15-year-old adolescents with a non-academic educational aspiration (46.0%) than among adolescents with an academic aspiration (18.3%). Gender (boys more than girls), older age (only in 2018), less parental monitoring, lower school achievement, and a lower level of health literacy explained around 28% of the variance in weekly energy drink consumption in both years. Conclusion: According to the findings, interventions to decrease the energy drink consumption, should be targeted at all adolescents, but especially at those with fewer individual resources. The interventions should also pay attention to family-level factors.

Problematic Social Media Use and Health among Adolescents.

(1) Background: The use of social media has become an integral part of adolescents' daily lives. However, the intensive use of social media can develop into a health-threatening addiction, but unfavourable health consequences can occur even with less use. Social media user groups categorized as no-risk, moderate risk (of developing problematic behaviour), and problematic use were examined with reference to their prevalence, their associations with individual determinants and health, and the increased health risk between groups. (2) Methods: The Finnish nationally representative HBSC data (persons aged 11, 13, and 15, n = 3408) and descriptive and binary logistic regression analysis were applied. (3) Results: Problematic social media use (9.4%) was most common among older age groups, and among persons with moderate/low school achievement, low health literacy, and low parental monitoring. Belonging to a moderate risk group (33.5%) was most frequent among girls, and among adolescents with low/moderate parental monitoring and health literacy. All the negative health indicators systematically increased if the respondent belonged to a moderate risk or problematic use group. (4) Conclusions: The study confirmed the association between problematic social media use and negative health outcomes and highlighted the need to pay close attention to adolescents at moderate risk who exhibited negative health outcomes.

Test-retest reliability of selected items of Health Behaviour in School-aged Children (HBSC) survey questionnaire in Beijing, China.

BACKGROUND: Children's health and health behaviour are essential for their development and it is important to obtain abundant and accurate information to understand young people's health and health behaviour. The Health Behaviour in School-aged Children (HBSC) study is among the first large-scale international surveys on adolescent health through self-report questionnaires. So far, more than 40 countries in Europe and North America have been involved in the HBSC study. The purpose of this study is to assess the test-retest reliability of selected items in the Chinese version of the HBSC survey questionnaire in a sample of adolescents in Beijing, China. METHODS: A sample of 95 male and female students aged 11 or 15 years old participated in a test and retest with a three weeks interval. Student Identity numbers of respondents were utilized to permit matching of test-retest questionnaires. 23 items concerning physical activity, sedentary behaviour, sleep and substance use were evaluated by using the percentage of response shifts and the single measure Intraclass Correlation Coefficients (ICC) with 95% confidence interval (CI) for all respondents and stratified by gender and age. Items on substance use were only evaluated for school children aged 15 years old. RESULTS: The percentage of no response shift between test and retest varied from 32% for the item on computer use at weekends to 92% for the three items on smoking. Of all the 23 items evaluated, 6 items (26%) showed a moderate reliability, 12 items (52%) displayed a substantial reliability and 4 items (17%) indicated almost perfect reliability. No gender and age group difference of the test-retest reliability was found except for a few items on sedentary behaviour. CONCLUSIONS: The overall findings of this study suggest that most selected indicators in the HBSC survey questionnaire have satisfactory test-retest reliability for the students in Beijing. Further test-retest studies in a large and diverse sample, as well as validity studies, should be considered for the future Chinese HBSC study.

How Are Adolescents Sleeping? Adolescent Sleep Patterns and Sociodemographic Differences in 24 European and North American Countries.

PURPOSE: 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 (2013-2014 and 2017-2018). For each country, we calculated the age-standardized mean in sleep duration, timing, and consistency and the proportions meeting sleep recommendations on school and nonschool days from self-reported bedtimes and wake times. We conducted stratified analyses by gender, age, and family affluence group. RESULTS: Adolescent sleep patterns varied cross-nationally. The average sleep duration ranged between 7:47 and 9:07 hours on school days and between 9:31 and 10:22 hours on nonschool days, and the proportion of adolescents meeting sleep recommendations ranged between 32% and 86% on school days and between 79% and 92% on nonschool days. Sleep patterns by gender and affluence groups were largely similar, but older adolescents slept less and went to bed later on school days than younger adolescents in all countries. CONCLUSIONS: The sleep patterns of adolescents vary across countries and sociodemographic groups. Insufficient sleep on school days is common in many countries. Public health and policy efforts to promote healthy adolescent sleep are encouraged.