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.

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.

Assessing Differences in the Implementation of Smoke-Free Contracts-A Cross-Sectional Analysis from the School Randomized Controlled Trial X:IT.

OBJECTIVE: The X:IT study is a school-based smoking preventive intervention that has previously been evaluated in a large randomized controlled trial (RCT) with good effects. However, the actual effect for participating students depends on the individual implementation. The aim of this study was to examine the implementation of smoke-free contract, which is one of the three main intervention components. Specifically, we examined whether it was implemented equally across family occupational social class (OSC), separately for boys and girls, the joint effect of OSC and gender, and the participants' own reasons for not signing a contract. RESULTS: Overall, the smoke-free contract was well implemented; 81.8% of pupils (total N = 2.015) signed a contract (girls 85.1, boys 78.6%). We found a social gradient among girls; more than 90% were in OSC group I vs. 75% in group VI. Among boys, however, we found no difference across OSC. Boys in all the OSC groups had about half the odds (i.e., medium OSC boys: OR = 0.48 (95% CI: 0.32-0.72) of having a smoke-free contract compared to girls from a high OSC. CONCLUSION: future interventions should include initiatives to involve families from all OSC groups and allow for different preferences among boys and girls.

Recurrent abdominal pain among adolescents: trends and social inequality 1991-2018.

OBJECTIVES: The association between socioeconomic status and recurrent abdominal pain (RAP) among adolescents is an understudied issue. No study has examined whether such an association changes over time. The aim was to examine trends in RAP among adolescents in Denmark from 1991 to 2018, to examine whether there was social inequality in RAP and whether this inequality varied over time. METHODS: The study used data from the Danish part of the international Health Behaviour in School-aged Children (HBSC) study of nationally representative samples of 11-, 13- and 15-year-olds. This study pooled data from eight comparable surveys from 1991 to 2018, overall participation rate 88.0%, n=30,048. The definition of RAP was self-reported stomach-ache daily or several days per week during the past six months. We reported absolute inequality as prevalence difference in RAP between low and high socioeconomic status and relative inequality as odds ratio for RAP by socioeconomic status. RESULTS: In the entire study population, 5.6% reported RAP, 3.1% among boys and 7.8% among girls. There was a significant increase in RAP from 1991 to 2018 among boys and girls, test for trend, p<0.0001. The prevalence of RAP was significantly higher in low than high socioeconomic status, OR=1.63 (95% CI: 1.42-1.87). The absolute social inequality in RAP fluctuated with no consistent increasing or decreasing pattern. CONCLUSIONS: The prevalence of RAP increased from 1991 to 2018. The prevalence was significantly higher among girls than among boys, and significantly higher in low socioeconomic status families. Professionals should be aware of RAP as common and potentially serious health problems among children and adolescents. In addition to clinical examination it is important to focus on improving the child's quality of life, reduce parents' and children's concerns about the seriousness of the condition, and consider supplements to medicine use.

Trends in social inequality in overweight and obesity among adolescents in Denmark 1998-2018.

OBJECTIVES: The aim was to analyze trends in overweight and obesity in relation to socioeconomic position among Danish adolescents in the 20-year period 1998-2018. METHODS: The study used data on self-reported height and weight and parents' occupational social class (OSC) from 11-, 13- and 15-year-old schoolchildren in 1998, 2002, 2006, 2010, 2014 and 2018, n = 22,177. The analyses included absolute social inequality in overweight/obesity (prevalence difference between low and high OSC) and relative social inequality (OR for overweight/obesity). RESULTS: In the total sample, the prevalence of overweight and obesity was 9.7% and 1.4%, respectively, with significantly higher prevalence in low than high OSC. There were significantly increasing trends in both overweight and obesity 1998-2018 in low OSC and no significant increase in high OSC. The OR for overweight was 1.59 (1.42-1.74) in middle and 2.16 (1.89-2.46) in low OSC, OR for obesity 1.74 (1.29-2.34) in middle and 2.97 (2.15-4.11) in low OSC. Associations were not modified by survey year. CONCLUSIONS: There was a persistent absolute and relative social inequality in overweight and obesity 1998-2018 among Danish adolescents.

Intake of sugar sweetened soft drinks among adolescents: Trends and social inequality in Denmark 2002-2018.

BACKGROUND: Intake of sugar sweetened soft drinks (SSSD) has decreased among adolescents, but trends in social inequality in SSSD intake are unknown. AIM: Examine trends in social inequality in SSSD intake among adolescents in Denmark during 2002-2018. METHODS: Five Health Behaviour in School-aged Children surveys with data on SSSD intake and parents' occupational social class (OSC) from nationally representative samples of 11, 13 and 15 year olds, n =20,112. RESULTS: The overall prevalence of daily SSSD intake decreased from 10.1% in 2002 to 6.4% in 2018. The prevalence decreased in both high OSC (from 8% to 5%) and middle OSC (from 10% to 6%) but remained around 12% in low OSC. The odds ratio (OR) estimates of low compared with high OSC increased over the years around an overall OR of 2.01 (1.74-2.34). CONCLUSIONS: Danish adolescents' SSSD intake decreased during 2002-2018 and was higher the lower the parents' OSC. Thus, social inequality increased during 2002-2018.

Trends in socioeconomic differences in daily smoking among 15-year-old Danes 1991-2014.

Aim: To examine trends in socioeconomic differences in daily smoking among 15-year-old Danes between 1991-2014, using occupational social class as indicator of socioeconomic status. Methods: The study included 15-year-olds participating in seven Danish Health Behaviour in School-aged Children studies between 1991-2014, n = 8,641. The analyses focused on absolute socioeconomic differences (prevalence difference between low and high occupational social class) and relative socioeconomic differences communicated by odds ratio for daily smoking. Results: The prevalence of daily smoking declined from 18.6% in 1991 to 4.5% in 2014. Across all surveys, the prevalence was 8.9% in high, 12.8% in middle and 16.5% in low occupational social classes (p < 0.0001). The absolute socioeconomic differences increased from 1991 to 2006 and declined thereafter. Across all survey years, the odds ratio (95% confidence interval) for daily smoking was 1.40 (1.19-1.65) in middle and 1.90 (1.56-2.32) in low versus high occupational social classes. The statistical interaction between occupational social class and survey year was significant (p = 0.0404), suggesting increasing relative socioeconomic differences from 1991 to 2014. Conclusions: There was a substantial decline in daily smoking among 15-year-olds between 1991-2014 in all occupational social class groups. The prevalence of daily smoking was highest in the low occupational social class during the entire period. The absolute socioeconomic differences in daily smoking increased between 1991-2006 and declined thereafter. The relative socioeconomic differences increased over 1991-2014. Studies of change in socioeconomic differences over time should address both absolute and relative socioeconomic differences as they may result in different conclusions and because important improvement in prevalence patterns may be disguised by exclusive focus on changes in relative socioeconomic differences.

Short report: persistent social inequality in poor self-rated health among adolescents in Denmark 1991-2014.

The aim was to examine trends in social inequality in poor self-rated health (SRH) among adolescents in Denmark 1991-2014. The analysis included 18 996 11-15-year-old school children from the cross-sectional Health Behaviour in School-aged Children studies in 1991, 2002, 2006, 2010 and 2014. Across the five surveys, the prevalence of poor SRH was 14.2%, remaining almost unchanged from 1991 to 2014. The proportion with poor SRH was 12.2% in high, 14.3% in middle and 17.6% in low occupational social class. This social inequality in poor SRH was persistent during the entire study period, both in terms of absolute and relative social inequality.

Brief Report: Trends in Social Inequality in Drunkenness Among Danish Adolescents, 1991-2014.

OBJECTIVE: This study examined whether social inequality in frequent drunkenness among Danish adolescents changed from 1991 to 2014. METHOD: We used data from the international Health Behaviour in School-aged Children (HBSC) study, which provided nationally representative samples of 15-year-olds from seven comparable cross-sectional studies in Denmark (N = 8,655). The students provided data about frequency of drunkenness and parents' occupation. RESULTS: In total, 38.6% reported to have been drunk at least four times, decreasing from 44.2% in 1991 to 21.2% in 2014. Most of the decrease took place in the latter part of the period. This decrease was found in all occupational social classes, but there was no change in absolute social inequality in drunkenness four or more times reported from 1991 to 2014. The sex- and yearadjusted odds ratio for frequent drunkenness was 0.80, 95% CI [0.70, 0.93] in low compared with high occupational social class. The statistical interaction between survey year and occupational social class was insignificant (p = .3601); that is, there was no change in relative social inequality in frequent drunkenness over time. CONCLUSIONS: Drunkenness was more prevalent among adolescents from the high occupational social class, and this social inequality did not change from 1991 to 2014.

High impact of implementation on school-based smoking prevention: the X:IT study-a cluster-randomized smoking prevention trial.

BACKGROUND: Implementation fidelity describes how well an intervention is implemented in the real-world setting. Assessing implementation fidelity is essential in the understanding of intervention results. In most studies, implementation fidelity is measured insufficiently, though, not taking into account the complexity of the concept nor the intervention. The objective of the present study was to develop an overall quantitative measure of implementation fidelity, to examine the degree of implementation fidelity and the association of implementation and effect of a randomized school-based smoking prevention trial-the X:IT study. METHODS: A cluster-randomized trial testing is a multi-component intervention to prevent smoking among adolescents in 94 Danish elementary schools (51 intervention, 43 control schools). Participants were grade 7 pupils (mean age 12.5 years). Data was collected by electronic questionnaires among pupils at baseline (n = 4161), the first follow-up (n = 3764), and the second follow-up (n = 3269) and among school coordinators at intervention schools at the first and second follow-up (50 and 39 coordinators). INTERVENTION: The intervention included three components: (1) smoke-free school grounds, (2) smoke-free curriculum, and (3) parental involvement, contracts, and dialogues. Implementation fidelity was assessed by four domains: adherence, dose, quality of delivery, and participant responsiveness. These were combined into an overall school-wise implementation index. The association of implementation and smoking was examined by logistic regression analyses. RESULTS: One fourth of the schools was characterized as high implementers of the program (all three components) at both first (12 schools, 24.0 %) and second follow-up (11 schools, 28.2 %). Implementation fidelity was strongly associated with smoking at the first and second follow-up, e.g., the odds for smoking at schools with high implementation both years were OR = 0.44 (95 % CI 0.32 to 0.68). CONCLUSIONS: Using an overall measure based on several aspects of implementation fidelity, we showed a negative graded association between implementation and smoking. This study suggests that higher degrees of implementation will improve the effect of the X:IT intervention. Studying the association between implementation and effect is extremely important; only by doing so, we can distinguish the quality of the intervention from the success of the implementation. TRIAL REGISTRATION: Current Controlled Trials ISRCTN77415416.

Trends in Social Inequality in Tooth Brushing among Adolescents: 1991-2014.

This study examines whether social inequality in tooth brushing frequency among adolescents changed from 1991 to 2014. The data material was seven comparable cross-sectional studies of nationally representative samples of 11- to 15-year-olds in Denmark with data about frequency of tooth brushing and occupation of parents. The total number of participants was 31,464, of whom 21.7% brushed their teeth less than the recommended 2 times a day. The absolute social inequality measured as prevalence difference between low and high social class increased from 7.7% in 1991 to 14.6% in 2014. The relative social inequality assessed by odds ratios for infrequent tooth brushing also increased from 1991 to 2014.

Socioeconomic differences in emotional symptoms among adolescents in the Nordic countries: recommendations on how to present inequality.

AIMS: This comparative study examines absolute and relative socioeconomic differences in emotional symptoms among adolescents using standardised data from five Nordic countries and gives recommendations on how to present socioeconomic inequality. METHODS: The Health Behaviour in School-aged Children (HBSC) international cross-sectional study from 2005/2006 provided data on 29,642 11-15-year-old adolescents from nationally random samples in Denmark, Finland, Iceland, Norway and Sweden. The outcome was daily emotional symptoms. Family Affluence Scale (FAS) was used as indicator of socioeconomic position. We applied four summary measures of inequality: Prevalence Difference, Odds Ratio, Slope Index of Inequality and Relative Index of Inequality, and presented the socioeconomic inequality by a graphical illustration of the prevalence of emotional symptoms, the size of the FAS groups and the summary indices of inequality in each country. RESULTS: The prevalence of emotional symptoms ranged from 8.1% in Denmark to 13.2% in Iceland. There were large country variations in the size of the low FAS-group ranging from 2% in Iceland to 12% in Finland. The largest absolute and relative socioeconomic inequalities were found in Iceland and the smallest in Finland for girls and in Denmark for boys. CONCLUSIONS: Emotional symptoms were more common among nordic adolescents from low affluence families this association appeared in the study of both absolute and relative inequality. A comprehensive presentation of socioeconomic inequality should include the prevalence of the health outcome, the size of the socioeconomic groups, and the regression line representing the summary indices of inequality.

Close relations to parents and emotional symptoms among adolescents: beyond socio-economic impact?

OBJECTIVES: This study examined the relationship between trustful communication with parents and frequency of emotional symptoms in schoolchildren and whether this relationship was modified by the family's socio-economic position. METHODS: Pooled data (n = 15,646) from the Danish Health Behaviour in School-aged Children surveys 2002, 2006 and 2010 were analysed by multilevel multivariable logistic regression. RESULTS: 8 % of all schoolchildren reported emotional symptoms almost daily. Odds ratio for daily symptoms was 2.1 (1.8-2.4) for children without trustful communication with parents compared to children with trustful communication. This association appears unaffected by family occupational class. A substantial socio-economic gradient in emotional symptoms persisted, independent of parent-child communication. CONCLUSIONS: Trustful communication with parents might have a fundamental importance, regardless of socio-economic position.

Is bullying equally harmful for rich and poor children?: a study of bullying and depression from age 15 to 27.

BACKGROUND: Exposure to bullying in childhood and adolescence is harmful to health, well-being and social competence of the victim. However, little is known about the long-term consequences of bullying victimization. In this paper, we use a longitudinal study from age 15 to 27 to examine whether childhood socioeconomic position (CSP) modifies the association between exposure to bullying in childhood and symptoms of depression in young adulthood. METHODS: Nationally representative baseline sample in 1990 (n = 847), followed up 2002 (n = 614). We used multivariate analyses of variance to examine the influence of bullying on symptoms of depression at age 27. RESULTS: Analyses showed that exposure to bullying, low CSP and female gender significantly increased the risk of depression in young adulthood. There was a statistically significant interaction between bullying and CSP, so that bullying increased the risk of depression for people from low CSP, while there was only a weak association between bullying victimization and depressive symptoms for people from more affluent childhood socioeconomic backgrounds. The same pattern was found for analyses stratified by sex. CONCLUSION: Our study suggests that the effects of bullying may have more serious long-term implications on health for children from less affluent backgrounds. Our study points at bullying exposure as another pathway through which social adversity in childhood influences social inequalities in adult health. Political efforts are needed to improve norms and legislations about how to treat children and more specific interventions should take place in schools to reduce the exposure to bullying.

Socioeconomic inequality in exposure to bullying during adolescence: a comparative, cross-sectional, multilevel study in 35 countries.

OBJECTIVES: We examined the socioeconomic distribution of adolescent exposure to bullying internationally and documented the contribution of the macroeconomic environment. METHODS: We used an international survey of 162,305 students aged 11, 13, and 15 years from nationally representative samples of 5998 schools in 35 countries in Europe and North America for the 2001-2002 school year. The survey used standardized measures of exposure to bullying and socioeconomic affluence. RESULTS: Adolescents from families of low affluence reported higher prevalence of being victims of bullying (odds ratio [OR] = 1.13; 95% confidence interval [CI] = 1.10, 1.16). International differences in prevalence of exposure to bullying were not associated with the economic level of the country (as measured by gross national income) or the school, but wide disparities in affluence at a school and large economic inequality (as measured by the Gini coefficient) at the national level were associated with an increased prevalence of exposure to bullying. CONCLUSIONS: There is socioeconomic inequality in exposure to bullying among adolescents, leaving children of greater socioeconomic disadvantage at higher risk of victimization. Adolescents who attend schools and live in countries where socioeconomic differences are larger are at higher risk of being bullied.

Social position and functional decline among non-disabled old men and women.

BACKGROUND: To examine the relation between different aspects of social position and functional decline at 5 year follow-up in 75 year old men and women. METHODS: The study includes 606 non-disabled 75 year old participants living in Glostrup, Denmark. Functional ability was measured by the Mob-H Scale which measures need of help in six common mobility activities. Three outcome measures were used: a) functional decline, alive, b) functional decline, including death, and c) death. Measures of social position were vocational training, income and tenure. RESULTS: Income and tenure which reflect material wealth were related to functional decline and death in both men and women, but the patterns differed: housing tenure was related to functional decline and death among the men, while income was related to functional decline and death among the women. The associations were not attenuated when adjusted by behavioural factors. CONCLUSION: The results indicate that poor material wealth is associated with functional decline independent of behavioural factors in a selected population of non-disabled older adults. Thus, the cumulative influence of material wealth throughout the life-course cannot be avoided in old age just by a healthy behaviour once you have reached old age.

Cynical hostility, socioeconomic position, health behaviors, and symptom load: a cross-sectional analysis in a Danish population-based study.

OBJECTIVE: To analyze the cross-sectional association between cynical hostility and high symptom load in a Danish population-based study. Furthermore, the aim was to investigate to what extent health risk behaviors mediated this association. METHODS: Data were based on a postal questionnaire in a Danish random sample of 3426 men and 3699 women aged 40 or 50 years. Cynical hostility was measured by the 8-item Cynical Distrust Scale. High symptom load was assessed by physiological and mental symptoms experienced within the last 4 weeks. Confounders were age and socioeconomic position, while potential mediators were alcohol consumption, smoking, physical activity, and BMI. RESULTS: Higher cynical hostility was associated with self-reported symptom load. Health behaviors did not seem to mediate this effect. Socioeconomic position was a strong confounder for the effect on both health and health behaviors. After adjustment the effects of hostility on health remained with odds ratios of 2.1 (1.7-2.6) for women and 2.3 (1.8-2.8) for men. CONCLUSION: After adjustment for socioeconomic position, cynical hostility has an effect on self-reported high symptom load, and this effect is not mediated by health behaviors.