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

AIMS

The aim was to examine how loneliness was associated with bullying victimization at school and online.

METHODS

We used data from the Danish arm of the international Health Behavior in School-aged Children (HBSC) study from 2022. The study population was a nationally representative sample of 11-15-year-olds who completed the internationally standardized HBSC questionnaire at school, n = 5382. Multilevel logistic regression was applied to study the associations between bullying victimization and loneliness.

RESULTS

The prevalence of reporting loneliness often or very often was 9.0%; 6.3% of the sample experienced habitual bullying victimization at school, and 4.8% incurred cyberbullying. There was a strong and graded association between loneliness and bullying victimization at school and cyberbullying. The associations were significant for boys and girls, and the association between exposure to bullying at school and loneliness was steeper for boys than girls. The gradients were steeper for physical bullying than for cyberbullying. Students exposed to habitual bullying in both contexts had an adjusted OR (95% CI) of 11.21 (6.99-17.98) for loneliness.

CONCLUSION

Exposure to bullying at school and cyberbullying are strongly associated with loneliness. It is important to reduce bullying at school and on the internet and to promote effective interventions to reduce continuing loneliness.

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.

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.

On the time trends among school-aged children in the Nordic countries

Long-term trends in mental health of school-aged children can be analysed in the HBSC study. In Sweden the proportion of the children that report at least two weekly health complaints during the last six months has increased from the first data collection 1985/1985 to the latest 2017/2018 among all age groups for both girls and boys. Among the 11-year-old it reached 41 % among girls and 30 % boys, and among 15-year-old girls 62 % and boys 35 %. Can we trust this?

The prevalence of two or more weekly health complaints showed large differences by country over time and especially in 2014, when Iceland and Sweden showed an almost 10%-point larger prevalence of multiple weekly symptoms (about 35%) than Denmark, Finland and Norway (about 25%). Norway was the only country to show a decline during 2002-2014.

The prevalence of sleep difficulties has increased over the 12-year period in Denmark, Iceland, and Finland. In Sweden the prevalence fell from 26% to 21% from 2002 to 2006 but rose by 10% points from 2010 to 2014. Only Norway showed a positive development over the 12-year period; the prevalence declined in 2014 to 17% the lowest prevalence of sleep difficulties in any of the five Nordic countries.

The trend of excellent self-rated health for Nordic adolescents indicates a small overall improvement between 2002 and 2006 but a stable trend in the following periods up until 2014. Finland and especially Sweden shows a decline in the prevalence of students having an excellent self-rated health. The only country to show a positive development in the prevalence of students having excellent self-rated health from 2002 to 2014, is Norway. The overall prevalence of adolescents having high life satisfaction has declined in most of the Nordic countries examined.

Setting the scene: controversies on trends in mental health among adolescents in the Nordic countries

At present there are different positions regarding trends in adolescent mental health. Can we trust trend data on the mental health among adolescents in the Nordic countries? Some question the trustworthiness of adolescent self-reports, which describe ordinary daily hassles as health complaints, which cannot be interpreted as signs of mental disorders. In addition, today there is a more open climate for talking about mental issues, which can lead to an overestimation of the prevalence of mental disorders.

Statistics on mental health services statistics report increased psychopharmaceutic prescriptions as well as consumption of professional care. Such data argues for increased governmental investment in adolescent mental health services. Is this pattern due to increased availability of mental health services and/or increased prevalence of mental health problems in the adolescent population?

A concern is that data availability influences policymaking and allocation of resources. If there is an emphasis on self-reported data from adolescents that may an increased risk of medicalization of young people's dealing with their daily lives. If on the other hand the reported problems among young people is disregarded, this would be against the UN Child Convention.

The survey data has important qualities especially if the data is analysed and reported properly. The validation of survey measure has been done both regarding psychometric quality and content validity. Advanced analysis of the data can draw a more nuanced picture. Moreover, some screening instruments have been developed as a first step towards making diagnosis. Instead the HBSC surveys ask boys and girls about their health and well-being, social environment and health behaviours. HBSC uses findings at national and international levels to gain new insights into young people's health and wellbeing, understand the social determinants of health, and inform policy and practice to improve young people's lives.

Trends in social inequality in loneliness among adolescents 1991-2014

BACKGROUND

Loneliness and social inequality in health are important public health concerns. We examined (i) trends in loneliness among adolescents from 1991 to 2014 in Denmark and (ii) trends in social inequality in loneliness.

METHODS

Study population: 11-15-year olds in random samples of schools in 1991, 1994, 1998, 2006 and 2014, n = 19 096. Loneliness was measured by a single item and social background by parents' occupational social class (OSC). We calculated absolute (%) differences in loneliness between high and low OSC and relative differences by odds ratio for loneliness.

RESULTS

Across all surveys, 6.3% reported feeling lonely. The prevalence increased from 4.4% in 1991 to 7.2% in 2014. The prevalence of loneliness in high, middle and low OSC was 5.8, 5.9 and 8.0%. The increase in loneliness was more pronounced in higher than lower OSC, resulting in a decreasing absolute social inequality in loneliness. The statistical interaction between OSC and survey year was significant, P = 0.0176, i.e. the relative social inequality in loneliness also decreased from 1991 to 2014.

CONCLUSION

The prevalence of loneliness increased from 1991 to 2014. The social inequality in loneliness decreased in both absolute and relative terms because of a rising prevalence of loneliness among children from high OSC.

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.

Difficulties falling asleep among adolescents: Social inequality and time trends 1991-2018

Sleep problems in adolescence are increasingly common, and associated with adverse health and psychological outcomes. Adolescents' sleep problems may be related to the family's socioeconomic status, but studies are few and no study has examined whether social inequality in sleep problems changes as sleep problems become increasingly common. This study examined trends in difficulties falling asleep among adolescents in Denmark, whether this sleep problem was associated with socioeconomic status, and whether this association changed from 1991 to 2018. The study applied data from eight comparable surveys among 11-15 year olds in Denmark 1991-2018, the Danish arm of the international Health Behaviour in School-aged Children study, N = 30,002. The prevalence of daily difficulties falling asleep increased from 7.0% to 13.4% in 1991-2018 with higher frequencies among girls and younger adolescents. The odds ratio (95% confidence interval) for daily difficulties was 1.14 (1.05-1.24) in middle and 1.52 (1.37-1.69) in low compared with high socioeconomic status. The absolute social inequality in difficulties falling asleep was persistent in 1991-2018 whereas the relative social inequality may have decreased. The increasing prevalence and the social inequality in difficulties falling asleep among adolescents is a serious public health concern that calls for more attention and efforts.

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.

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.

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.

Measurement of alienation among adolescents: construct validity of three scales on powerlessness, meaninglessness and social isolation

Background

Psychological alienation is an important concept in the study of adolescents’ health and behavior but no gold standard for measuring alienation among adolescents exists. There is a need for new scales with high validity for use in adolescent health and social research. The purpose of the present study was to develop and validate alienation scales in accordance with Seeman’s conceptualization of alienation focusing on three independent variants specifically relevant in adolescent health research: powerlessness, meaninglessness and social isolation.

Methods

Cross-sectional data from 3083 adolescents aged 13 to 15 years from the Danish contribution to the cross-national study Health Behaviour in School-aged Children (HBSC) were used. We identified and developed items, addressed content and face validity through interviews, and examined the criterion-related construct validity of the scales using graphical loglinear Rasch models (GLLRM).

Results

The three scales each comprised three to five face valid items. The powerlessness scale reflected the adolescent’s expectancy as to whether his/her behavior can determine the outcome or reinforcement he/she seeks. The meaninglessness scale reflected the expectancy as to whether satisfactory predictions regarding the effects of one’s behavior are possible. Finally, the social isolation scale reflected whether the adolescent had a low expectancy for inclusion and social acceptance. All scales contained some uniform local dependency and differential item functioning. However, only to a limited degree, which could be accounted for using GLLRM. Thus the scales fitted GLLRMs and can therefore be considered to be essentially construct valid and essentially objective.

Conclusion

The three alienation scales appear to be content and face valid and fulfill the psychometric properties of a good construct valid reflective scale. This suggests that the scales may be appropriate in future large-scale surveys to examine the relation between alienation and a range of adolescent health outcomes such as health, behavior and wellbeing.

Electronic supplementary material

The online version of this article (10.1186/s41687-018-0040-y) contains supplementary material, which is available to authorized users.

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.

Socioeconomic position and smoking behaviour in Danish adults

Aims: The associations between smoking and various socioeconomic indicators may have different implications and causes, which may also vary according to sex and birth cohort. This study analyses how two dimensions of socioeconomic position, an individual ( education) and a structural ( occupation) indicator, are associated with ever, current and ex-smoking. Methods: Data on smoking behaviour were collected in five cross-sectional surveys of random samples of the general Danish population aged 20 years or more at intervals between 1982 and 1994. In total, 8,054 men and 8,281 women participated. Logistic regression was used to analyse the infl uence of education and occupation on smoking behaviour controlling for sex and birth cohort. Results: In cohorts born after 1930 ever and current smoking were related to years of school education and current occupation. The prevalences of ever and current smoking were highest among the least educated, unskilled workers, unemployed persons and persons who received welfare benefits. A significant interaction between birth cohort and education indicated that the educational difference in ever and current smoking increased significantly with increasing year of birth. In multivariate analysis controlling for sex and birth cohort, ex-smoking seemed to be more strongly associated with education than occupation .Those with 12 or more years of school education had twice as high a chance of being ex-smokers as those with 7 years of school or less. Conclusion: Smoking behaviour is strongly associated with both individual and structural indicators of socioeconomic position in Danish adults in all cohorts except for those born before 1930.

Loneliness and Ethnic Composition of the School Class: A Nationally Random Sample of Adolescents

Loneliness is a public health concern that increases the risk for several health, behavioral and academic problems among adolescents. Some studies have suggested that adolescents with an ethnic minority background have a higher risk for loneliness than adolescents from the majority population. The increasing numbers of migrant youth around the world mean growing numbers of heterogeneous school environments in many countries. Even though adolescents spend a substantial amount of time at school, there is currently very little non-U.S. research that has examined the importance of the ethnic composition of school classes for loneliness in adolescence. The present research aimed to address this gap by exploring the association between loneliness and three dimensions of the ethnic composition in the school class: (1) membership of ethnic majority in the school class, (2) the size of own ethnic group in the school class, and (3) the ethnic diversity of the school class. We used data from the Danish 2014 Health Behaviour in School-aged Children survey: a nationally representative sample of 4383 (51.2 % girls) 11-15-year-olds. Multilevel logistic regression analyses revealed that adolescents who did not belong to the ethnic majority in the school class had increased odds for loneliness compared to adolescents that belonged to the ethnic majority. Furthermore, having more same-ethnic classmates lowered the odds for loneliness. We did not find any statistically significant association between the ethnic diversity of the school classes and loneliness. The study adds novel and important findings to how ethnicity in a school class context, as opposed to ethnicity per se, influences adolescents' loneliness.

Trends in overweight prevalence among 11-, 13- and 15-year-olds in 25 countries in Europe, Canada and USA from 2002 to 2010

BACKGROUND

The purpose of this study was to assess recent changes in the prevalence of overweight (including obesity) among 11-, 13- and 15-year-olds in 33 countries from 2002 to 2010.

METHODS

Data from 25 countries from three consecutive survey cycles (2002, 2006 and 2010) that had at least 80% response rate for self-reported height, weight and age were analysed using logistic regression analysis.

RESULTS

Overweight prevalence increased among boys in 13 countries and among girls in 12 countries; in 10 countries, predominantly in Eastern Europe, an increase was observed for both boys and girls. Stabilization in overweight rates was noted in the remaining countries; none of the countries exhibited a decrease over the 8-year period examined. In the majority of countries (20/25) there were no age differences in trends in overweight prevalence.

CONCLUSION

In over half of the countries examined overweight prevalence did not change during 2002-2010. However, increasing overweight prevalence was noted in many Eastern European countries over this time period. Overweight prevalence remained high in several countries in Europe and North America. These patterns call for continued research in youth overweight and highlight the need to understand cross-national differences by examining macro-level indicators. Such research should feed into developing sound translations and practices to prevent and reduce overweight in youth.

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.

Adolescent alcohol use: a reflection of national drinking patterns and policy?

AIMS

To analyse how adolescent drunkenness and frequency of drinking were associated with adult drinking patterns and alcohol control policies.

DESIGN, SETTING AND PARTICIPANTS

Cross-sectional survey data on 13- and 15-year-olds in 37 countries who participated in the Health Behaviour in School-Aged Children (HBSC) Study in 2010 (n = 144 788) were linked to national-level indicators on alcohol control policies and adult drinking patterns.

MEASUREMENTS

Outcome measures were self-reported weekly drinking and life-time drunkenness (drunk once or more). Data were analysed using multi-level logistic regression models.

FINDINGS

In the mutually adjusted models, adolescent drunkenness was associated significantly with high adult alcohol consumption [odds ratio (OR) = 3.15 among boys, 95% confidence interval (CI) = 2.13-4.64, OR girls = 2.44, CI = 1.57-3.80] and risky drinking patterns in the adult population (OR boys = 2.02, CI = 1.33-3.05, OR girls = 1.61, CI = 1.18-2.18). The level of abstainers in the adult population was also associated significantly with girls' drunkenness; a 10% increase in the number of abstainers in a country reduced the odds of drunkenness with 21% (OR = 0.79, CI = 0.68-0.90). Weekly drinking was associated significantly with weak restrictions on availability (OR boys = 2.82, CI = 1.74-4.54, OR girls = 2.00, CI = 1.15-3.46) and advertising (OR boys = 1.56, CI = 1.02-2.40, OR girls = 1.79, CI = 1.10-2.94).

CONCLUSIONS

Comparing data cross-nationally, high levels of adult alcohol consumption and limited alcohol control policies are associated with high levels of alcohol use among adolescents.

Do eating behaviors in the general population account for country variance in glycemic control among adolescents with diabetes: the Hvidoere Study Group and the Health Behaviour in School-Aged Children study

BACKGROUND

The Hvidoere Study Group (HSG) has demonstrated major differences in glycemic control between pediatric diabetes centers which remain largely unexplained. This study investigates whether these differences are partly attributable to healthy eating norms in the background population.

METHODS

The study involved adolescents from 18 countries from (i) the Health Behaviour in School-Aged Children study (HBSC) and (ii) the HSG. There were 94 387 participants from representative HBSC samples of 11-, 13- and 15-yr-olds and 1483 11- to 15-yr-old adolescents with diabetes from the HSG. The frequency of intake of fruit, vegetables, sweets, sugary soft drinks, and daily breakfast was compared between the two groups. The glycemic control of the adolescents in the HSG cohort was determined by measuring glycated hemoglobin (HbA1c).

RESULTS

Across countries in the HSBC survey, there was substantial variation in prevalence of healthy eating behavior and even greater variation between adolescents from the HSG centers. In all countries more adolescents with diabetes reported healthy eating behavior compared to national norms. In individuals healthy eating behavior had a significant effect on the individual level HbA1c. There was no significant correlation between the frequencies of these healthy eating behaviors at (i) the national level and (ii) diabetes center level and the center mean HbA1c.

CONCLUSIONS

Although individual healthy eating behavior is associated with better glycemic control at the individual level, such eating behavior does not explain the center differences in HbA1c. Similarly, the reported healthy eating norm of the background populations does not explain the variation in glycemic control among centers.

Adolescent alcohol use reflects community-level alcohol consumption irrespective of parental drinking

PURPOSE

Risk factors for adolescent alcohol use are typically conceptualized at the individual level, and school- and community-level risk factors have received little attention. Based on the theoretical understanding of youth alcohol consumption as a reflection of community social practice, we analyzed whether adolescent drunkenness was related to community-level adult alcohol use (AAC), when taking individual and school-level risk factors for drunkenness into account. Furthermore, we investigated whether the association between community-level AAC and adolescent drunkenness was attenuated after inclusion of parental drinking.

METHODS

We used data from three sources: data about adolescent drunkenness from the Health Behavior in School-Aged Children 2010 survey (N = 2,911; 13- to 15-year-olds nested in 175 school classes and 51 schools); data about community-level AAC derived from the Danish National Health Survey 2010 (177,639 participants); and data on school-level variables from Health Behavior in School-Aged Children School Leader Survey 2010. We performed multilevel logistic regression analysis with data from students nested within school classes and schools.

RESULTS

Overall, 33.5% of students had been drunk twice or more. High community-level AAC was significantly associated with adolescent drunkenness (odds ratio [95% confidence interval], 1.94 [1.21-3.11]). Parental drinking was strongly related to adolescent drunkenness but did not attenuate the relationship between community-level AAC and adolescent drunkenness. We found no association between adolescent drunkenness and school-level variables (youth friendly environment, alcohol education, and exposure to alcohol outlets).

CONCLUSIONS

Adolescent drunkenness was associated with community-level AAC and was not explained by parental drinking.

Validity of self-reported height and weight among adolescents: the importance of reporting capability

Background

This study proposes a new approach for investigating bias in self-reported data on height and weight among adolescents by studying the relevance of participants’ self-reported response capability. The objectives were 1) to estimate the prevalence of students with high and low self-reported response capability for weight and height in a self-administrated questionnaire survey among 11–15 year old Danish adolescents, 2) to estimate the proportion of missing values on self-reported height and weight in relation to capability for reporting height and weight, and 3) to investigate the extent to which adolescents’ response capability is of importance for the accuracy and precision of self-reported height and weight. Also, the study investigated the impact of students’ response capability on estimating prevalence rates of overweight.

Methods

Data was collected by a school-based cross-sectional questionnaire survey among students aged 11–15 years in 13 schools in Aarhus, Denmark, response rate =89%, n = 2100. Response capability was based on students’ reports of perceived ability to report weight/height and weighing/height measuring history. Direct measures of height and weight were collected by school health nurses.

Results

One third of the students had low response capability for weight and height, respectively, and every second student had low response capability for BMI. The proportion of missing values on self-reported weight and height was significantly higher among students who were not weighed and height measured recently and among students who reported low recall ability. Among both boys and girls the precision of self-reported height and weight tended to be lower than among students with low response capability. Low response capability was related to BMI (z-score) and overweight prevalence among girls. These findings were due to a larger systematic underestimation of weight among girls who were not weighed recently (−1.02 kg, p < 0.0001) and among girls with low recall ability for weight (−0.99 kg, p = 0.0024).

Conclusion

This study indicates that response capability may be relevant for the accuracy of girls’ self-reported measurements of weight and height. Consequently, by integrating items on response capability in survey instruments, participants with low capability can be identified. Similar analyses based on other and less selected populations are recommended.

Postthrombotic syndrome and quality of life in patients with iliofemoral venous thrombosis treated with catheter-directed thrombolysis

BACKGROUND

Postthrombotic syndrome (PTS) is a common complication after iliofemoral venous thrombosis, often resulting in poor quality of life (QOL) among the affected patients. This study assessed development of PTS and its effect on QOL among patients treated for iliofemoral venous thrombosis by catheter-directed thrombolysis.

METHODS

Patients admitted with an iliofemoral venous thrombosis and treated with catheter-directed thrombolysis at Gentofte University Hospital from 1999 to 2008 were invited to participate. Duplex ultrasound imaging was used to assess venous patency and valve function. Each patient completed the generic Short-Form 36-item (SF-36) health survey assessment, producing physical component (PCS) and mental component summary (MCS) scores, and the disease-specific Venous Insufficiency Epidemiological and Economic Study (VEINES)-Quality of Life (QOL)/Symptoms (Sym), questionnaires to assess QOL. PTS was assessed using the Villalta scale.

RESULTS

The study included 109 patients. Median follow-up was 71 months. PTS developed in 18 patients (16.5%) and of those, initial thrombolysis was successful in 13. Patients with PTS had significantly worse mean ± standard deviation scores than patients without PTS on VEINES-QOL (34.2 ± 9.6 vs 53.1 ± 6.6; P < .0001), VEINES-Sym (34.0 ± 8.8 vs 53.2 ± 6.6; P < .0001), SF-36 MCS (44.2 ± 15.5 vs 52.3 ± 11.0; P = .005), and SF-36 PCS (42.3 ± 9.1 vs 53.5 ± 7.8; P < .0001) subscales. Patients with reflux or chronic occlusions, or both, had significantly lower mean ± SD scores than patients with patent veins without reflux on VEINES-QOL (43.5 ± 14.3 vs 51.0 ± 8.8; P = .044) and SF-36 PCS (47.2 ± 10.9 vs 52.4 ± 8.5; P = .049) scales.

CONCLUSION

PTS was associated with worse QOL, although only a few patients developed PTS after catheter-directed thrombolysis of iliofemoral venous thrombosis. Patients with patent veins and sufficient valves have higher QOL scores than patients with reflux and occluded veins.

Pathways and mechanisms in adolescence contribute to adult health inequalities

AIMS

This paper presents a model that encompasses pathways and mechanisms working over adolescence that contribute to adult health inequalities. We review evidence on the four mechanisms: socially differential exposure, tracking, socially differential tracking, and socially differential vulnerability.

METHODS

We conducted literature searches in English-language peer-reviewed journals using PubMed (from 1966 to May 2009) and PsycINFO, and combined these with hand-searches of reference lists, journals, and authors of particular relevance.

RESULTS

Most health indicators are socially patterned in adolescence and track into adulthood, with higher risks of adverse outcomes among individuals from lower socioeconomic positions. Adolescent health behaviours track into adulthood. Smoking, physical activity, and especially fruit and vegetable intake are socially patterned, while evidence for social patterning of alcohol use is less consistent. Relational dimensions like lone parenthood and bullying are socially patterned and track over time, and there are indications of a socially differential vulnerability to the effects of these types of relational strain. Very little research has investigated the social patterning of the above indicators over time or studied social vulnerability of these indicators from adolescence to adulthood. However, all four mechanisms seem to be active in establishing social differences in adult educational attainment.

CONCLUSIONS

We find the Adolescent Pathway Model useful for providing an overview of what elements and mechanisms in adolescence may be of special importance for adult health inequalities. There is a lack of knowledge of how social patterns of health, health behaviours, and social relations in adolescence transfer into adulthood and to what extent they reflect themselves in adult health.

Socioeconomic position, macroeconomic environment and overweight among adolescents in 35 countries

OBJECTIVE

It is important to understand levels and social inequalities in childhood overweight within and between countries. This study examined prevalence and social inequality in adolescent overweight in 35 countries, and associations with macroeconomic factors.

DESIGN

International cross-sectional survey in national samples of schools.

SUBJECTS

A total of 11-, 13- and 15-year-olds from 35 countries in Europe and North America in 2001-2002 (N=162 305).

MEASUREMENTS

The main outcome measure was overweight based on self-reported height and weight (body mass index cut-points corresponding to body mass index of 25 kg/m(2) at the age of 18 years). Measures included family and school affluence (within countries), and average country income and economic inequality (between countries).

RESULTS

There were large variations in adolescent overweight, from 3.5% in Lithuanian girls to 31.7% in boys from Malta. Prevalence of overweight was higher among children from less affluent families in 21 of 24 Western and 5 of 10 Central European countries. However, children from more affluent families were at higher risk of overweight in Croatia, Estonia and Latvia. In Poland, Lithuania, Macedonia and Finland, girls from less affluent families were more overweight whereas the opposite was found for boys. Average country income was associated with prevalence and inequality in overweight when considering all countries together. However, economic inequality as measured by the Gini coefficient was differentially associated with prevalence and socioeconomic inequality in overweight among the 23-high income and 10-middle income countries, with a positive relationship among the high income countries and a negative association among the middle income countries.

CONCLUSION

The direction and magnitude of social inequality in adolescent overweight shows large international variation, with negative social gradients in most countries, but positive social gradients, especially for boys, in some Central European countries. Macroeconomic factors are associated with the heterogeneity in prevalence and social inequality of adolescent overweight.

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.

The mediation proportion: a structural equation approach for estimating the proportion of exposure effect on outcome explained by an intermediate variable

It is often of interest to assess how much of the effect of an exposure on a response is mediated through an intermediate variable. However, systematic approaches are lacking, other than assessment of a surrogate marker for the endpoint of a clinical trial. We review a measure of "proportion explained" in the context of observational epidemiologic studies. The measure has been much debated; we show how several of the drawbacks are alleviated when exposures, mediators, and responses are continuous and are embedded in a structural equation framework. These conditions also allow for consideration of several intermediate variables. Binary or categorical variables can be included directly through threshold models. We call this measure the mediation proportion, that is, the part of an exposure effect on outcome explained by a third, intermediate variable. Two examples illustrate the approach. The first example is a randomized clinical trial of the effects of interferon-alpha on visual acuity in patients with age-related macular degeneration. In this example, the exposure, mediator and response are all binary. The second example is a common problem in social epidemiology-to find the proportion of a social class effect on a health outcome that is mediated by psychologic variables. Both the mediator and the response are composed of several ordered categorical variables, with confounders present. Finally, we extend the example to more than one mediator.

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.

Revitalising the Metropolit 1953 Danish male birth cohort: background, aims and design

Recent research indicates that factors operating during childhood are related to adult health. Thus, longitudinal studies with information on subsequent phases may be key to understanding later health outcomes. The main objective of this paper is to describe the history and design of a Danish birth cohort, and its revitalisation. In 1965, information from birth certificates for 11 591 of a total of 12 270 males born in 1953 in the Metropolitan area of Copenhagen, Denmark were traced. These boys were the study population of a sociological investigation conducted with the aim of describing social mobility. At age 12 years, 9537 of these cohort members completed a questionnaire in school, which included cognitive measures and information on social aspirations and leisure time activities. In 1966 educational performance tests were administered for these boys and, in 1968, mothers of 2890 cohort members were interviewed regarding family social backgrounds. With the establishment of the Civil Registration System (CRS) in 1968, it was possible to identify 11 532 cohort members. In 2002 we began the process of revitalising this study with the aim of investigating the influence of early life factors on later health. We succeeded in ascertaining the vital status of all subjects in the CRS. This showed that 863 subjects had died between 1968 and 2002. Linkages to the Register of Causes of Death, the National Hospital Register, Psychiatric Central Register and Danish Cancer Registry have been completed. In total, 7969 cohort members had been hospitalised for any somatic illness and, according to the Psychiatric Central Register, 1382 men had been admitted to a psychiatric hospital or ward. In the Cancer Registry we found 363 of our study participants. Analyses exploring the influence of social conditions in early life, birth dimensions, and childhood cognition on adult health experience are at various stages of completion. A questionnaire-based postal follow-up survey is planned. Thus, the Metropolit study provides an important opportunity to examine the processes by which factors that operate over the life course influence adult health.

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.

Socioeconomic position in early life, birth weight, childhood cognitive function, and adult mortality. A longitudinal study of Danish men born in 1953

OBJECTIVE

To examine the relation between socioeconomic position in early life and mortality in young adulthood, taking birth weight and childhood cognitive function into account.

DESIGN

A longitudinal study with record linkage to the Civil Registration System and Cause of Death Registry. The data were analysed using Cox regression.

SETTING

The metropolitan area of Copenhagen, Denmark.

SUBJECTS

7493 male singletons born in 1953, who completed a questionnaire with various cognitive measures, in school at age 12 years, and for whom birth certificates with data on birth and parental characteristics had been traced manually in 1965. This population was followed up from April 1968 to January 2002 for information on mortality.

MAIN OUTCOME MEASURES

Mortality from all causes, cardiovascular diseases, and violent deaths.

RESULTS

Men whose fathers were working class or of unknown social class at time of birth had higher mortality rates compared with those whose fathers were high/middle class: hazard ratio 1.39 (95% CI 1.15 to 1.67) and 2.04 (95% CI 1.48 to 2.83) respectively. Birth weight and childhood cognitive function were both related to father's social class and inversely associated with all cause mortality. The association between father's social class and mortality attenuated (HR(working class)1.30 (1.08 to 1.56); HR(unknown class)1.81 (1.30 to 2.52)) after control for birth weight and cognitive function. Mortality from cardiovascular diseases and violent deaths was also significantly higher among men with fathers from the lower social classes.

CONCLUSION

The inverse association between father's social class at time of birth and early adult mortality remains, however somewhat attenuated, after adjustment for birth weight and cognitive function.

Tiredness in daily activities among nondisabled old people as determinant of onset of disability

The purpose of this article was to examine whether self-reported tiredness in daily activities at age 75 is an independent determinant of onset of disability at 5-year follow-up. The investigation is based on two subgroups of nondisabled participants of 75 year olds who survived and participated in the follow-up study 5 years later (n = 510 and 429). Persons who felt tired in their daily activities had a larger risk of becoming disabled in mobility (OR = 3.2, 95% CI = 1.4-7.6) and in daily activities (OR = 2.1, 95% CI = 1.0-4.2) compared to persons without tiredness. In addition, persons with poor cognitive function, little diversity in social relations and no physical activity had an independent risk of onset of disability. The results indicate that it is important to take it seriously when older people complain about tiredness in daily activities, as these people are at higher risk of becoming disabled than others.

Exposure to teachers smoking and adolescent smoking behaviour: analysis of cross sectional data from Denmark

OBJECTIVE

To determine whether adolescent smoking behaviour is associated with their perceived exposure to teachers or other pupils smoking at school, after adjustment for exposure to smoking at home, in school, and best friends smoking.

DESIGN

Logistic regression analysis of cross sectional data from students in Denmark.

SUBJECTS

1515 grade 9 students (mean age 15.8) from 90 classes in 48 Danish schools.

OUTCOME MEASURE

Self reported smoking behaviour; daily smoking and heavy smoking, defined as those smoking more than 20 cigarettes per week.

RESULTS

Of the students in this study, 62% of boys and 60% of girls reported being exposed to teachers smoking outdoors on the school premises. The proportion of boys and girls reporting to have been exposed to teachers smoking inside the school building were 86% and 88%, respectively. Furthermore, 91% of boys and 92% of girls reported that they had seen other students smoking outdoors on the school premises. Adolescents' perceived exposure to teachers smoking outdoors on the school premises was significantly associated with daily smoking, having adjusted for sex, exposure to teachers smoking indoors at school and pupils smoking outdoors at school, as well as the smoking behaviour of mother, father, and best friend (odds ratio (OR) 1.8, 95% confidence interval 1.2 to 2.8). Adolescents' perceived exposure to teachers smoking inside the school building was not associated with daily smoking (OR 0.9, 95% CI 0.5 to 1.6) and perceived exposure to pupils smoking outdoors was not associated with daily smoking (adjusted OR 1.5, 95% CI 0.5 to 4.4). There were similar findings with heavy smoking as the outcome variable.

CONCLUSIONS

Teachers smoking during school hours is associated with adolescent smoking. This finding has implications for future tobacco prevention strategies in schools in many countries with liberal smoking policies where it might provide support for those working to establish smokefree schools.

Cohabitation and marital status as predictors of mortality--an eight year follow-up study

In a follow-up study of 1265 women and men aged 50, 60 and 70 years, we analysed how mortality was associated with cohabitation status (living alone/not living alone), living with/without a partner, and marital status respectively. Data originate from a longitudinal questionnaire study of a random sample of people born in 1920, 1930 and 1940 with baseline in 1990. Survival time for all individuals were established during the next 8 years until May 1998. Multivariate Cox analysis stratified by age and gender showed that individuals living alone experienced a significantly increased mortality compared to individuals living with somebody HR = 1.42(1.04-1.95) adjusted for functional ability, self-rated health, having children, smoking, diet and physical activity. Similar analyses were performed for the variable living with/without a partner HR = 1.38(1.01-1.88) and marital status HR = 1.25(0.93-1.69), adjusted for the same covariates. Inclusion of the health behaviour variables--smoking, diet and physical activity--one by one to a model with functional ability, self-rated health and one of the three determinants (cohabitation status, living with/without partner, marital status) showed no effect on the association with mortality. Hereby, we found no evidence of an indirect effect of health behaviours on the association between living arrangements and mortality. In contrast to many previous studies, we found no significant gender and age differences in the association between living arrangement and mortality. We suggest that in future studies of social relations and mortality, cohabitation status is considered to replace marital status as this variable may account for more of the variation in mortality.

Tiredness as determinant of subsequent use of health and social services among nondisabled elderly people

OBJECTIVE

To examine whether self-reported tiredness in daily activities at age 75 is an independent determinant of incident hospitalization and use of home services 5 years later.

METHODS

In all, 275 people participated in a prospective study in Glostrup, Denmark, when they were 75 and 80 years old. Four subgroups were created according to whether participants had been hospitalized or used home care in the year before the baseline study and whether or not they were disabled at the time. The key predictor variables were measured by two scales about tiredness in daily activities.

RESULTS

Nondisabled individuals who felt tired in their daily activities had about twice the risk of being hospitalized and of being users of home help 5 years later.

CONCLUSIONS

Because tiredness in daily activities is related to subsequent hospitalization and use of home help, it should be taken seriously in preventive services among elderly people.

Socioeconomic position and smoking behaviour in Danish adults

AIMS

The associations between smoking and various socioeconomic indicators may have different implications and causes, which may also vary according to sex and birth cohort. This study analyses how two dimensions of socioeconomic position, an individual (education) and a structural (occupation) indicator, are associated with ever, current and ex-smoking.

METHODS

Data on smoking behaviour were collected in five cross-sectional surveys of random samples of the general Danish population aged 20 years or more at intervals between 1982 and 1994. In total, 8,054 men and 8,281 women participated. Logistic regression was used to analyse the influence of education and occupation on smoking behaviour controlling for sex and birth cohort.

RESULTS

In cohorts born after 1930 ever and current smoking were related to years of school education and current occupation. The prevalences of ever and current smoking were highest among the least educated, unskilled workers, unemployed persons and persons who received welfare benefits. A significant interaction between birth cohort and education indicated that the educational difference in ever and current smoking increased significantly with increasing year of birth. In multivariate analysis controlling for sex and birth cohort, ex-smoking seemed to be more strongly associated with education than occupation. Those with 12 or more years of school education had twice as high a chance of being ex-smokers as those with 7 years of school or less.

CONCLUSION

Smoking behaviour is strongly associated with both individual and structural indicators of socioeconomic position in Danish adults in all cohorts except for those born before 1930.

Tests of data quality, scaling assumptions, and reliability of the Danish SF-36

We used general population data (n = 4084) to examine data completeness, response consistency, tests of scaling assumptions, and reliability of the Danish SF-36 Health Survey. We compared traditional multitrait scaling analyses to analyses using polychoric correlations and Spearman correlations. The frequency of missing values was low, except for elderly people and people with lower levels of education. Response consistency was high and compared well with results for the U.S. SF-36. For respondents with computable scales in all eight domains, scaling assumptions (item internal consistency, item discriminant validity, equal item-own scale correlations, and equal variances) were satisfactory in the total sample and in all subgroups. The SF-36 could discriminate between levels of health in all subgroups, but there were skewness, kurtosis, and ceiling effects in many subgroups (elderly people and people with chronic diseases excepted). Concerning correlation methods, we found interesting differences indicating advantages of using methods that do not assume a normal distribution of answers as an addition to traditional methods.

Differential item functioning in the Danish translation of the SF-36

Statistical analyses of Differential Item Functioning (DIF) can be used for rigorous translation evaluations. DIF techniques test whether each item functions in the same way, irrespective of the country, language, or culture of the respondents. For a given level of health, the score on any item should be independent of nationality. This requirement can be tested through contingency-table methods, which are efficient for analyzing all types of items. We investigated DIF in the Danish translation of the SF-36 Health Survey, using two general population samples (USA, n = 1,506; Denmark, n = 3,950). DIF was identified for 12 out of 35 items. These results agreed with independent ratings of translation quality, but the statistical techniques were more sensitive. When included in scales, the items exhibiting DIF had only a little impact on conclusions about cross-national differences in health in the general population. However, if used as single items, the DIF items could seriously bias results from cross-national comparisons. Also, the DIF items might have larger impact on cross-national comparison of groups with poorer health status. We conclude that analysis of DIF is useful for evaluating questionnaire translations.

Social relations and mortality. An eleven year follow-up study of 70-year-old men and women in Denmark

PURPOSE

To identify which aspects of social relations among 70-year-old men and women are predictive of mortality 11 years later.

METHODS

The baseline study in 1984 included 734 70-year-old men and women in Glostrup (county of Copenhagen). The variables comprised the structure and the function of the social network, education, income and functional ability. Eleven years later, in November 1995, information about deaths was obtained from the Central National Register.

RESULTS

The study showed an independent association between social relations and mortality. Men who did not help others with repairs and who lived alone and women with no social support to other tasks had increased risk of dying during the follow-up period.

CONCLUSIONS

This study supports (1) that there is an association between social relations and mortality, (2) that two aspects of the function of social relations matters: (a) to receive support for small or larger tasks needed, (b) to help others with different tasks, and (3) that social relations may serve different functions for men and women.

[Late effects of occupational organic brain damage in painters 6-8 years after diagnosis. Occurrence of mental and psychosomatic health problems and utilization of health services]

With the object of illustrating effects on health and social functions of occupational organic brain damage, a questionnaire study was carried out in 1986 concerning 192 brain-damaged painters and a reference group of 341 other painters. The study was repeated in 1990 to elucidate effects six to eight years after diagnosis. In 1986 a high prevalence of mental and psychosomatic symptoms was found among the brain-damaged painters. The prevalence correlated with severity of the disease, occupational situation and social network. In 1990 the same level of symptoms was found. In the reference group the prevalence of symptoms increased from 1986 to 1990. Besides the major difference in the prevalence of symptoms between the two groups, the level of symptoms correlated to the occupational situation in both groups. Twenty-seven percent of the brain-damaged painters were still at work in 1990. The high symptom level among the brain-damaged painters is considered to be chronic.

[Work load and cardiovascular risk factors. A cross-sectional study of employed Danish men and women]

As part of World Health Organisation initiated MONICA project, 2000 men and women aged 30, 40, 50 and 60 from the general population were invited to undergo a medical examination with special emphasis on cardiovascular disease. A total of 1504 (75%) participated, 1209 of whom were employed. The participants answered a questionnaire on working, social, and health conditions and underwent clinical examinations that included the measurement of blood pressure and serum cholesterol triglycerides, high density lipoprotein, fibrinogen and glycosylated haemoglobin (HbA1C) concentrations. Using the demand control model for measuring job strain suggested by Karasek, the employed people were classified according to those who had suffered job strain and those who had not in two different ways. The subjective classification was based on the participants' statements regarding demand and control in their jobs, whereas the objective classification was based on job title and mode of payment. More women than men were classified as having high strain jobs. After adjusting for age and sex no significant association was found between coronary risk factors and subjective job strain. A tendency for an association between fibrinogen and job strain was found. Body mass index and HbA1C concentration were significantly associated with objective job strain independent of confounders.

[Methylmethacrylate and organic dementia. A dose-response analysis among dental technicians and opticians]

The substance methylmethacrylate (MMA) is an organic solvent which is employed inter alii for prostheses which is suspected of being neurotoxic. With the object of illustrating whether there is a connection between exposure to MMA and symptoms of organic dementia, a cross-sectional investigation was carried out on a population consisting of occupationally active dental technicians and opticians (n = 528) and a group of dental technicians who were no longer occupationally active (n = 173). No noteworthy difference in the background variables, apart from age, was observed. Age was taken into consideration in the analysis. The results show a statistically significant increase in the prevalence of the chronic symptoms on increasing exposure. Where the acute symptoms are concerned, the connection is not statistically significant, but a tendency is observed. A chronic symptom index constructed on the basis of 13 questions concerning chronic symptoms is compared with the life exposure and the age. A statistically significant increase in the index was found with exposure to MMA, although not for the oldest age group. The pattern symptoms, presence of bias and other forms of exposure are discussed. It is concluded that this investigation confirms the hypothesis that symptoms of organic dementia have a connection the exposure to MMA. The results support the presumption that MMA causes acute and chronic damage to the central nervous system even with exposure below the safety limits. It is recommended that the occupational environment of dental technicians, including the present safety limits, should be revised.

A double-blind randomized study of the effect of erythromycin in preventing pelvic inflammatory disease after first trimester abortion

OBJECTIVE

To assess the prophylactic use of erythromycin in prevention of post-abortal pelvic inflammation disease (PID) in first trimester abortion.

DESIGN

Double-blind, randomized controlled trial.

SETTING

Department of Surgery, County Hospital, Denmark.

SUBJECTS

Four hundred and thirty two women who were to undergo induced abortion before 12 weeks gestation were randomized to be treated either with prophylactic erythromycin or a placebo.

INTERVENTION

The women were randomized to receive a placebo or erythromycin, 500 mg twice a day for 7 1/2 days starting the evening before the abortion. All the women were investigated for Chlamydia trachomatis and Neisseria gonorrhoea before the abortion.

MAIN OUTCOME MEASURES

Frequency of cervical C. trachomatis and N. gonorrhoea and frequency of PID after abortion.

RESULTS

Fifty four women were excluded after randomization. The frequency of PID was 11% (20/189) in the erythromycin group and 16% (30/189) in the placebo group (P = 0.13, chi 2-test). The prevalence of C. trachomatis was 19% (15/78) in women less than or equal to 20 years of age, 13% (14/109) in women between 21 and 25 years and 2% (5/241) in women greater than or equal to 26 years of age. In women positive for C. trachomatis erythromycin prophylaxis significantly reduced the frequency of PID to 8% (1/13) compared with 43% (6/14) in the placebo group (P = 0.051, logistic regression analysis). Erythromycin had no effect on other potential high risk groups (first pregnancy, nulliparous, less than 20 years of age, and women with previous PID).

CONCLUSION

Prophylactic erythromycin is not warranted for all women having an abortion. Cervical C. trachomatis is a risk factor for postabortal PID, and prophylaxis with erythromycin significantly reduces the frequency of PID. However, only a few women with PID had cervical C. trachomatis, and the prevention of post-abortal PID remains a major challenge requiring further studies.

General practitioners' attitudes to a recent change in their remuneration system

The study examines the attitudes of general practitioners in Copenhagen to a recent change in their remuneration system from capitation to a mixed capitation and fee-for-service system. The study was based on two questionnaires, one before and one 18 months after the change, distributed to a primarily self-selected sample of 100 general practioners in Copenhagen City. The questionnaires provided information about certain basic characteristics of the respondents, attitudes to the new remuneration system as compared with the former, and possible changes in attitudes towards professional competence and responsibilities in secondary versus primary care. The majority of the respondents did not feel any changes under the new remuneration system in terms of diagnostic and curative possibilities and their relations to colleagues and patients. Attitudes to secondary versus primary care responsibilities also changed little. The majority felt that there had been an increase in their total work load, but also an improved economic situation in their practice. 21% felt that there was more competition with colleagues and 30% that doctor-patient relationships had suffered as a result of the introduction of a fee-for-service.