A focus on adolescent substance use in Europe, central Asia and Canada. Health Behaviour in School-aged Children international report from the 2021/2022 survey. Volume 3

The Health Behaviour in School-aged Children (HBSC) study is a large school-based survey carried out every four years in collaboration with the WHO Regional Office for Europe. HBSC data are used at national/regional and international levels to gain new insights into adolescent health and well-being, understand the social determinants of health and inform policy and practice to improve young people’s lives. The 2021/2022 HBSC survey data are accompanied by a series of volumes that summarize the key findings around specific health topics. This report, Volume 3 in the series, focuses on adolescent substance use, using the unique HBSC evidence on adolescents aged 11, 13 and 15 years across 44 countries and regions in Europe, central Asia and Canada. It describes the status of adolescent substance use (cigarette smoking, electronic cigarette use, alcohol consumption, drunkenness and cannabis use), the role of gender, age and social inequality, and how adolescent substance use has changed over time. Findings from the 2021/2022 HBSC survey provide an important evidence benchmark for current research, intervention and policy-planning.

Smoking is a Risk Factor for Generation Z, Too: The Evolution of the Attitudes.

Objectives: Generation Z, defined as "post-millennial," is considered to be the first generation that could end smoking. The objective is also to take into account the evolutionary aspect of the smoking and attitudes of the Generation Z. The aim of this study was to explore the willingness of Generation Z in Slovakia to comply with the legislation adopted in the field of anti-tobacco policy and to investigate some selected social factors-intention, subjective norm and percevied behavioral control-that contribute to a lower rate of compliance. Methods: Global Youth Tobacco Survey (GYTS) data on cigarette smoking among 3,557 adolescents (age range 13-15) in 2016 as well as on attitudes towards tobacco use and control measures were used to explore the level of compliance of adolescents with anti-tobacco regulations in Slovakia within the Framework Convention of Tobacco Control (FCTC). We used the concept of intention as explained in Ajzen's theory of planned behaviour (1985), focusing on the role of subjective norm and perceived behavioural control. Results: We found a decrease in ever smoking, current smoking and frequent smoking. We found that these adolescents start experimenting with dependence-causing substances, such as tobacco, regardless of existing rules. Conclusion: Adolescents were attracted to smoking, although they were aware of health effects of passive smoking, and a vast majority liked smoke-free places. They are also influenced by their peers and parental models.

Does tobacco use among adolescents come out of style in Czechia and Slovakia? Findings from the Global Youth Tobacco Survey between 2002 and 2016.

OBJECTIVES: The aim of this study is to analyse Global Youth Tobacco Survey (GYTS) data on a prevalence of tobacco use, indicators of tobacco control and pro-tobacco activities in Czechia and Slovakia between 2002 and 2016. METHODS: GYTS is a school-based survey of students aged 13-15 years carried out in Czechia and Slovakia in 2002/2003, 2007, 2011 and 2016. Standardized uniform questionnaires provided representative data. RESULTS: Between 2002 and 2016 the current cigarette smoking declined both in Czechia and Slovakia (from 34.6% and 26.4% to 15.2% and 17.1%, respectively). Indicators of tobacco control activities either did not change (access to buy cigarettes by minors) or decreased (school-based and mass media interventions). Indicators of pro-tobacco activities declined (being ever offered by a free tobacco product and having something with a tobacco product brand logo on it). CONCLUSIONS: Tobacco use is on decline and the situation becomes similar to the most of European countries. Preventive activities are only partially responsible for the process. Rather effect of global trends accelerated by widespread use of social media can play a role.

Forecasting Frequent Alcohol Use among Adolescents in HBSC Countries: A Bayesian Framework for Making Predictions.

(1) Aim: To summarize alcohol trends in the last 30 years (1985/6-2017/8) among 15-year-olds in Health Behaviour in School-aged Children (HBSC) countries (overall sample size: 413,399 adolescents; 51.55% girls) and to forecast the potential evolution in the upcoming 2021/22 HBSC survey. (2) Methods: Using 1986-2018 prevalence data on weekly alcohol consumption among 15-year-olds related to 40 HBSC countries/regions, a Bayesian semi-parametric hierarchical model was adopted to estimate trends making a clusterization of the countries, and to give estimates for the 2022 HBSC survey. (3) Results: An overall declining trend in alcohol consumption was observed over time in almost all the countries. However, compared to 2014, some countries showed a new increase in 2018 and 2021/22 estimates forecast a slight increase in the majority of countries, pointing out a potential bounce after a decreasing period in frequent drinking habits. (4) Conclusions: The clusterization suggested a homogenization of consumption habits among HBSC countries. The comparison between 2022 observed and expected data could be helpful to investigate the effect of risk behaviour determinants, including the pandemic impact, occurring between the last two waves of the survey.

Alcohol Use and Its Affordability in Adolescents in Slovakia between 2010 and 2018: Girls Are Less Adherent to Policy Measures.

BACKGROUND: The article analyzes selected indicators of alcohol use (weekly use, drunkenness within last month) and the ability of adolescents to buy alcohol in Slovakia between 2010 and 2018. METHODS: Health Behavior in School-Aged Children (HBSC) is a cross-sectional questionnaire study. A standardized uniform questionnaire was used to create a representative sample of 15-year-old adolescents. Two surveys carried out in Slovakia in 2010 (n = 1568) and 2018 (n = 1298) were analyzed. RESULTS: Weekly alcohol use and drunkenness declined only in boys, not in girls. Affordability of alcohol (not being prevented from buying it) declined among weekly drinking boys (from 60.4 to 34.1%) but remained almost unchanged in girls from a higher socioeconomic group compared to those from a lower one (57.9% vs. 30.6% in 2018). CONCLUSIONS: Affordability of alcohol in boys decreased with a decline in alcohol use, corresponding with implemented legislative measures. However, it remained unchanged in girls from a higher socioeconomic group.

Determination of Cadmium and Chromium in Fruit Spirits Intended for Own Consumption Using Graphite Furnace Atomic Absorption Spectrometry.

INTRODUCTION: Analysis of the occurrence of cadmium and chromium in selected samples of fruit spirits intended for own consumption. MATERIAL AND METHODS: In our pilot study, we analysed 89 samples of fruit spirits intended for own consumption. The samples were mineralized with use of microwave decomposition system MULTIWAVE 60 50 Hz and analysed by atomic absorption spectrometry with a graphite furnace (AAS GBC XPLORAA 5000 with GF 5000). RESULTS: Most of the analysed samples originated from plums (39), apples (38) and pears (5). The average ethanol concentration was 53.7%. Cadmium and chromium were detected in all samples. The highest concentration of chromium and cadmium was found in the apple spirit (31.9 ± 6.6 µg/l and 40.1 ± 8.3 µg/l). CONCLUSIONS: The ethanol concentration in the samples was higher than in distribution spirits. Concentrations of chromium in all samples did not exceed the limit given by the Slovak legislation or the limit of the AMPHORA. The permissible cadmium concentration (10 µg/l according to the AMPHORA) was exceeded in 9 samples. This indicates the potential importance of cadmium compared to chromium. Due to the lack of information in this field, the study presents an important starting point for further research.

Private wells as potential sources of heavy metal exposure: a pilot study in northwest Slovakia.

OBJECTIVES: The aim of this study is to analyse levels of selected heavy metals: chromium (Cr), cadmium (Cd), copper (Cu), manganese (Mn), and lead (Pb), and to recognize factors related to wells' stewardship. METHODS: The pilot study was realized in May 2018 in three villages in northwest of Slovakia. We analysed 69 water samples from private wells. The data on wells and well owners were obtained by self-administered questionnaire. The samples were analysed by atomic absorption spectroscopy with graphite furnace GF AAS (AAS GBC XplorAA 5000 with GBC GF 5000) equipped with hollow cathode lamps. Levels of heavy metals were compared with parametric values for drinking water stated in the Resolution of the Ministry of Health of the Slovak Republic No. 247/2017 Coll. RESULTS: The results indicated spatial variability in some heavy metal levels. Cadmium was not quantified in any sample. Copper and chromium levels were below the parametric value. Parametric values for manganese and lead were exceeded in 19 (27.5%) and 2 (2.9%) samples, respectively. Only 18 owners tested water quality. Busyness and financial cost most frequently discouraged users to carry out the water quality analysis. CONCLUSIONS: The presence of heavy metals in well water can pose a serious public health problem, especially in rural areas without public water supply. Education on heavy metals' risks targeted at well owners could increase the awareness of the issue and minimize possible public health consequences.

Measles Outbreak in a Roma Community in the Eastern Region of Slovakia, May to October 2018.

BACKGROUND: Despite the effective National Immunization Programme of Slovakia, some population groups are incompletely vaccinated or unvaccinated. We aimed to describe the measles outbreak spread in Eastern Slovakia between May and October 2018, affecting the Roma communities in relation to the existing immunity gaps. METHODS: We defined a group of persons living in socially closed communities with low vaccination coverage. RESULTS: Of 439 measles cases (median age: 10 years), 264 (60.1%) were vaccinated, 137 (31.2%) received two doses and 127 (28.9%) one dose of measles vaccines, 155 (35.3%) were unvaccinated and 20 (4.6%) had an unknown vaccination status. Samples from 102 patients (with two-dose vaccination status) were additionally tested for antibodies against rubella and mumps. Of 102 cases, 68 (66.7%) cases had a positive IgM and 23 (22.5 %) IgG antibodies against measles. For rubella, only 20 (19.6%) cases had seropositive IgG levels, for mumps higher positivity was detected in 60 persons (58.8%). We could detect only a small percentage with positive serology results of rubella IgG antibodies across all age groups. We have assumed that rubella antibodies had to be produced following the vaccination. Their absence in the cases with two doses of MMR suggests that these vaccines could not have been administrated despite the fact that this data was included in the medical records. Sequential analysis of two samples showed measles genotype B3. CONCLUSION: This outbreak can outline the existence of a vulnerable group of the Roma. Low vaccinate coverage represents a serious public health threat.

Selected Behavioural Factors Affecting Oral Health in Schoolchildren: Results from the Health Behaviour in School-Aged Children (HBSC) Slovak Study.

Oral diseases, particularly dental caries, affect as much as nine in 10 persons globally. Its development starts during childhood. Behavioural factors play an important role in its aetiology. The aim of the research was to analyse the prevalence of selected behavioural factors associated with dental caries in Slovak adolescents. Selected factors, such as toothbrushing less than once a day, consumption of sweets and sweetened soft drinks daily and their combination, were analysed using data from Health Behaviour in School-Aged Children surveys carried out in 2005/2006, 2009/2010, 2013/2014 and 2017/2018 in Slovakia. The target group consisted of 11- to 13-year-old schoolchildren. The results were analysed by sex and socioeconomic status. The consumption of sweets and sweetened soft drinks, despite declining, remains widespread (41.3% of boys and 39.6% of girls in 2017/2018). The absence of daily toothbrushing, similarly as a co-occurrence of factors, were more frequent in boys (10.6% and 5.0% in 2017/2018, respectively) than in girls (5.1% and 2.3% in 2017/2018, respectively). The absence of daily toothbrushing was associated with a lower socioeconomic situation. In conclusion, behavioural risk factors affecting oral health are widespread in Slovak adolescents. Despite the positive development of the epidemiological situation, effective interventions, as well as the improvement of oral hygiene in lower socioeconomic groups, are needed.

Eating-Disordered Behavior in Adolescents: Associations with Body Image, Body Composition and Physical Activity.

Eating disorders (EDs) represent a disparate group of mental health problems that significantly impair physical health or psychosocial functioning. The aim of this study was to present some evidence about the prevalence of eating-disordered behavior (EDB) in adolescents, and explore its associations with body image (BI), body composition (BC) and physical activity (PA) in this age group. Data from 780 adolescents participating in a health behavior in school-aged children (HBSC) study conducted in Slovakia in 2018 were used (mean age 13.5 ± 1.3; 56% boys). Differences in mean values of numerical indicators were evaluated using the independent samples t-test. Differences between nominal variables were assessed by the chi-square test. Pearson correlation was used to describe the associations between all the selected variables. EDB was positively screened in 26.7% (208/780) of adolescents, with a higher prevalence in girls (128/344, 37.2%) than in boys (80/436, 18.3%). Significantly higher means of BI, body weight (BW), body mass index (BMI), body fat mass (BFM), body fat percentage (BFP), body fat mass index (BFMI), fat free mass index (FFMI), and SCOFF questionnaire score (SCOFF QS) were found in those positively screened for EDB. Pearson correlation analysis revealed positive associations between EDB and BI, BW, BMI, BFM, BFP and BFMI. The prevalence of EDB is high in Slovak adolescents. Positive associations between EDB, BI, BMI and fat-related body composition parameters support the idea of a more integrated approach in EDs and obesity prevention and treatment. At the same time, gender differences suggest the need for considering gender-specific strategies aimed at girls and boys separately.

Lead contamination of fruit spirits intended for own consumption as a potential overlooked public health issue? A pilot study.

OBJECTIVE: The aim of the study was to analyse the occurrence of lead in selected samples of fruit distilled spirits for own consumptions in terms of possible contribution to the occurrence of alcohol-attributable diseases. METHODS: In a pilot study, we analysed 18 samples of fruit spirits for own consumption. Most of the samples were distilled in the local growing distilleries in the Zilina Region with exception of 3 samples collected in the Trnava Region (one of them was of Hungarian origin). Sample preparation included previous mineralization with use of microwave decomposition system Multiwave 60 50 Hz. The samples were analysed by atomic absorption spectroscopy with graphic furnace (AAS GBC XplorAA 5000 with GF 5000). RESULTS: The average ethanol level in our samples was higher in comparison with distributed spirits. We detected lead in all samples. In two of them the concentration was lower than the limit of quantitation (LOQ). The highest lead concentrations were observed in plum spirit from Hungary (581.0 µg/l), and in grape spirit made in the Trnava Region (466.3 µg/l). CONCLUSIONS: Lead is a widespread contaminant of fruit spirits prepared for own consumption. Taking into consideration its common occurrence and possible multiplicative effect with ethanol, we can assume that lead can contribute to the occurrence of several alcohol-attributable chronic diseases. Due to the insufficient information in this field, our results provide significant insight into the issue and present an important starting point for further research.

The Effects of a Workplace Health Promotion Program to Decrease Cadmium Exposure Levels in Nickel-Cadmium Battery Workers.

OBJECTIVE: Cadmium exposure is a common problem in the production of nickel-cadmium batteries. However, keeping the respective legislative occupational and safety policies is essential, but there are problems with compliance. We analysed the effect of strategies to increase compliance with precautions during 20132015 on 59 workers at a nickel-cadmium battery factory. MATERIAL AND METHODS: A health promotion program was implemented in two phases. The first phase included comprehensive education on the importance of appropriate behaviour and changes to the sanitation program. The second phase included renovation of sanitary facilities and modernization of the air exhaust ventilation. RESULTS: The initial median cadmium urinary level in workers was 1.9 µg/g creatinine. After the first phase of interventions, levels dropped to 1.0 µg/g creatinine. After the second phase no significant further decrease was observed. CONCLUSION: Comprehensive education and changes in the sanitation program were able to halve cadmium levels and can be considered a useful and cost-effective preventive tool.

Body-image Dissatisfaction and Weight-control Behaviour in Slovak Adolescents.

OBJECTIVES: The aim of the study was to examine body-image dissatisfaction in adolescents aged 13-15 years reporting to be on a diet and to assess gender and age differences in weight-reduction behaviour in Slovak adolescents. METHODS: Data on a representative sample of 2,765 adolescents (mean age 14.37 years) from the Slovak part of Health Behaviour in School Aged Children Study carried out in 2014 were analysed. Self-reported body-image dissatisfaction and engagement in weight-reduction behaviour of 13 to 15-year-old adolescents was assessed using multiple logistic regression models. RESULTS: More that 20% of boys and 35% of girls perceived themselves to be too fat. Girls reported being on a diet more frequently than boys (28.8% vs. 14.9%). The most frequent weight-reduction behaviours were drinking more water (67.7%), eating more fruits and vegetables (67.1%), and consuming fewer sweets (60.5%) and soft drinks (51.7%). Girls prevailed above boys in the use of these dietary methods. Age differences were not apparent, except for smoking, believed to help in weight reduction and used upmost by 15-year-olds (8.9%) followed by 14 and 13-year-olds, 6.0% and 4.1%, respectively. CONCLUSIONS: Body-image dissatisfaction and weight-control behaviour are issues particularly in girls, however, they did not necessarily correspond with actual obesity. The most commonly used weight-reduction behaviours are in the same way important aspects of a healthy lifestyle. There is room to improve obesity control, particularly within primary health care.

Estimation of the Population Susceptibility Against Measles in Slovakia.

OBJECTIVE: In Slovakia, thanks to a highly effective vaccination programme, no domestic cases of measles have been reported since 1999. However, there are several outbreaks of measles currently hitting some countries in Europe. Difficulties in reaching the goal of measles elimination make it necessary to monitor the status of the population susceptibility to prevent similar outbreaks in the future. We hypothesize that immunity wanes overtime, which can substantially impact the population susceptibility. This work introduces a model that estimates a proportion of individuals susceptible to measles in the Slovak population in 2015. METHODS: Our analysis is based on an age-cohort model that incorporates waning immunity, vaccination schedule and changes in demographic structure. The inputs of the model are data on the vaccination coverage, last seroprevalence survey in 2002 and age structure of the population. RESULTS: In a short-term horizon, waning immunity does not affect the estimated proportion of the susceptible population. However, in a long-term horizon, the antibody titers can fall below the level of protection, which would result in a substantial transfer of initially immune individuals to the compartment of the susceptible ones. Incorporating of waning immunity in the cohort model has indicated that the most susceptible cohorts are not-vaccinated youngest children and cohorts born between 1969 and 1986. CONCLUSIONS: Applying the model to the current situation shows that people aged 30-45 years and unvaccinated infants represent the most susceptible groups. Model partially replaces missing seroprevalence survey, but, because the parameters of model and phenomenon of waning immunity are not exactly known, we suggest reintroducing the regular national serosurveys in order to empirically determine the level of susceptibility for measles in Slovakia.

Legislative Norms to Control Cannabis Use in the Light of Its Prevalence in Czech Republic, Poland, Slovakia, and Hungary.

OBJECTIVES: Cannabis control legislation ranks among key measures to prevent social-health impacts of its use. The article qualitatively analyses respective legislation in the Czech Republic, Poland, Slovakia, and Hungary (Visegrad Four, V4) considering level of decriminalisation of cannabis use in relation to current epidemiological situation. METHODS: Qualitative analysis of the cannabis control legislation in V4 countries from 1995 to 2016 focusing on criminal liability, differentiation of cannabis from other illicit substances, definition of a small amount intended for personal use, sentences for possessing and dealership of the drug. Results: Slovakia, Hungary and Poland share similar restrictive legislative approach throughout the studied period. In the Czech Republic, the situation has been different and since 2010 cannabis has been further decriminalised: possession of defined small amount of drug not being under prosecution and milder sentences for cannabis than for other illicit psychoactive substances. RESULTS: Slovakia, Hungary and Poland share similar restrictive legislative approach throughout the studied period. In the Czech Republic, the situation has been different and since 2010 cannabis has been further decriminalised: possession of defined small amount of drug not being under prosecution and milder sentences for cannabis than for other illicit psychoactive substances. CONCLUSION: Although the prevalence of cannabis use among adolescents is the highest in the Czech Republic, partial decriminalisation did not show further increase. Slovakia, Hungary and Poland show different trends in epidemiological situation despite of similar legislative approach. Results indicate that beside legislation other social factors play a role and measures to change attitudes and decrease social tolerance are important.

Is educational differentiation associated with smoking and smoking inequalities in adolescence? A multilevel analysis across 27 European and North American countries.

This study aims to determine whether educational differentiation (i.e. early and long tracking to different school types) relate to socioeconomic inequalities in adolescent smoking. Data were collected from the WHO-Collaborative 'Health Behaviour in School-aged Children (HBSC)' study 2005/2006, which included 48,025 15-year-old students (Nboys = 23,008, Ngirls = 25,017) from 27 European and North American countries. Socioeconomic position was measured using the HBSC family affluence scale. Educational differentiation was determined by the number of different school types, age of selection, and length of differentiated curriculum at the country-level. We used multilevel logistic regression to assess the association of daily smoking and early smoking initiation predicted by family affluence, educational differentiation, and their interactions. Socioeconomic inequalities in both smoking outcomes were larger in countries that are characterised by a lower degree of educational differentiation (e.g. Canada, Scandinavia and the United Kingdom) than in countries with higher levels of educational differentiation (e.g. Austria, Belgium, Hungary and The Netherlands). This study found that high educational differentiation does not relate to greater relative inequalities in smoking. Features of educational systems are important to consider as they are related to overall prevalence in smoking and smoking inequalities in adolescence.

Nanomaterials - a New and Former Public Health Issue. The Case of Slovakia.

Nanoparticles exist for a long time as both inorganic and organic parts of nature. Recently, massive expansion of nanotechnologies is evidenced, together with intentional production of new nanoparticles which have not been in contact with living organisms until now. Besides obvious positive aspects, potential threats related to their exposure should be taken into consideration. Unique physical-chemical properties of nanoparticles cause a high bioactivity following their intake (through air, ingestion and skin) and unrestricted spread in exposed organs. Primary effects of nanoparticles on cellular level represent oxidative stress and reactions leading to apoptosis, autophagocytosis and necrosis. Number of studies indicating contribution of nanoparticles to numerous disorders has been recently increasing. However, detailed mechanisms of health effects are not well known. Similarly, there is insufficient information on life cycle of nanoparticles in the environment. Research in this field as well as legislation is behind rapid development and use of nanotechnologies. Considering absence of mandatory exposure limits and other protective measures, nanomaterials represent a potential threat for population health. Recommendations and guidelines of international institutions can contribute to deal with situation, however, passing of effective legislation both on national and European level is urgently needed.

Socioeconomic inequalities in the impact of tobacco control policies on adolescent smoking. A multilevel study in 29 European countries.

INTRODUCTION: There are concerns that tobacco control policies may be less effective in reducing smoking among disadvantaged socioeconomic groups and thus may contribute to inequalities in adolescent smoking. This study examines how the association between tobacco control policies and smoking of 15-year-old boys and girls among 29 European countries varies according to socioeconomic group. METHODS: Data were used from the Health Behaviour in School-aged Children (HBSC) study conducted in 2005/2006 comprising 50,338 adolescents aged 15 years from 29 European countries. Multilevel logistic regression analyses were conducted to assess the association of weekly smoking with components of the Tobacco Control Scale (TCS), and to assess whether this association varied according to family affluence (FAS). Analyses were carried out per gender and adjusted for national wealth and general smoking rate. RESULTS: For boys, tobacco price was negatively associated with weekly smoking rates. This association did not significantly differ between low and high FAS. Levels of tobacco-dependence treatment were significantly associated with weekly smoking. This association varied between low and high FAS, with higher treatment levels associated with higher probability of smoking only for low FAS boys. For girls, no tobacco policy was significantly associated with weekly smoking, irrespective of the FAS. CONCLUSIONS: Results indicated that most tobacco control policies are not clearly related to adolescent weekly smoking across European countries. Only tobacco price seemed to be adequate decreasing smoking prevalence among boys, irrespective of their socioeconomic status.

Trends in the co-occurrence of tobacco and cannabis use in 15-year-olds from 2002 to 2010 in 28 countries of Europe and North America.

BACKGROUND: Cannabis and tobacco use frequently co-occur. Adolescents who consume both substances experience more respiratory distress and psychosocial problems and are less likely to stop compared with those who use either tobacco or cannabis alone. This study examined time trends in tobacco and cannabis use among 15-year-olds in Europe and North America between 2002 and 2010. METHODS: Twenty-eight countries were included and merged into six regions based on their welfare systems. Adolescents (n = 142 796) were divided in four 'user groups': 'no-users', 'tobacco and cannabis users', 'tobacco-only users' and 'cannabis-only users'. Prevalence rates are reported by study-wave and region. Logistic regressions with study wave as independent variable were used to study trends in the user groups and regions. Interaction effects between time and gender were considered. RESULTS: Overall, tobacco use, and concurrent tobacco and cannabis use decreased by 3 and 3.7%, respectively, but prevalence rates varied by region. Only in North America, an interaction effect between time and gender was found in tobacco and cannabis users. CONCLUSIONS: Although this study demonstrates a decrease in tobacco and cannabis use in most regions, it also shows that the use of both substances is related. Therefore, studying the co-occurring use of tobacco and cannabis is necessary.

Perceived teacher unfairness and headache in adolescence: a cross-national comparison.

OBJECTIVES: The present study examines the prevalence of headache in early adolescents in 21 European and North-American countries and the role of perceived teacher unfairness in predicting this health complaint across different countries. METHODS: Data were taken from the "Health Behaviour in School-aged Children" study (HBSC), a World Health Organization cross-national survey on health behaviors in 11-, 13- and 15-year-old students. Headache and perceived teacher unfairness were measured through a self-administered questionnaire filled out by 115,212 adolescents. RESULTS: The overall prevalence of frequent headaches (at least once a week) was 28.8%, ranging from 18.9% in Slovenia to 49.4% in Israel. After adjusting for gender, grade, family affluence, school achievement, being bullied and lifestyles (drinking, smoking, eating and physical activity), teacher unfairness showed a significant association with frequent headache in all but two countries (Ukraine and Luxembourg). CONCLUSIONS: Our results show that headache is a common health symptom in European and North-American countries, even though there are substantial differences in its prevalence across countries. The study indicates that perceived teacher unfairness can be a significant predictor of frequent headache during adolescence, and this association is consistent across countries.