Latent transition analysis (LTA) is a useful statistical modelling approach for describe transitions between latent classes over time. LTA may be characterized in terms of prevalence at each time point and through transition probabilities over time. Investigating predictors of these transitions is often of key interest. Currently, LTA can mostly be carried out using commercial and specialized software and only to some limited extent by means of open source statistical software. This tutorial demonstrates a flexible and modular approach for LTA, providing a powerful alternative using R through a combination latent class analysis and multiple logistic regression models. This approach has several advantages from a modelling perspective, as demonstrated through revisiting a previously conducted LTA, published in PLoS ONE recently. In short, results were very similar to the original analysis using commercial software although some additional novel results were also obtained. The proposed alternative approach offers more options in terms of choice of effect measures, model assumptions such as hierarchical structures and covariate adjustment, and differential handling of missing data. R code snippets are provided in the tutorial. A detailed accompanying script is also provided for full reproducibility.

Preventing young people's cigarette smoking is a major public health priority, and smoking is especially prevalent in vocational schools. Well-enforced comprehensive school tobacco policies accompanied by preventive efforts show potential to reduce smoking, but the implementation process is crucial to achieve the intended effect. We investigate whether and how implementation fidelity of a multi-component smoking prevention intervention impacted student smoking outcomes after 4-5 months among students in Danish vocational education and training (national age range 15-65 years, mean 25.6) and preparatory basic education (national age range 15-25 years, mean 17.6) institutions using questionnaire data from a cluster-RCT. The intervention included a smoke-free school hours policy, educational curriculum, and class competition. We calculated an overall implementation fidelity measure combining staff-reported school-level delivery (fidelity) and student-reported receipt (participation, responsiveness), and used multilevel regression models to analyze associations with smoking outcomes (smoking daily, regularly, and during school hours). We supplemented the analysis with restricted cubic spline regression. Additionally, we stratified the analyses by school types and analyzed associations between implementation fidelity of the separate intervention components and smoking outcomes. High implementation was associated with lower odds of regular smoking (OR: 0.37, 95% CI: 0.18-0.78) and smoking during school hours, but not daily smoking, and these associations varied between the school settings. When analyzed separately, implementation fidelity of the components did not affect the outcomes significantly. Our findings underline the need to support the implementation process of school tobacco policy interventions to ensure the intended effects of reducing students' smoking.

Objective The escalating trends in poly-tobacco use among young people are worrying due to the heightened health consequences associated with use. This study aims to re-analyze data from a smoking reduction intervention applying latent transition analysis (LTA) to explore the effect of a smoking reduction intervention on the transition between tobacco and nicotine use behavior patterns, particularly poly-tobacco use, over time. Additionally, the effect of sociodemographic variables on transition patterns was explored. Methods From 2018 to 2020, a two-armed randomized controlled trial was conducted to evaluate a smoking reduction intervention focusing on a comprehensive school tobacco policy across 14 vocational schools in Denmark. Baseline and five-month follow-up surveys assessed self-reported use of cigarettes, e-cigarettes, smokeless tobacco, and waterpipe. This study was a secondary data analysis using latent transition analysis (LTA). The primary analysis of the trial did not find a significant overall effect of the intervention on tobacco use. Results A total of 2,158 students completed the baseline and/or follow-up surveys (mean age: 20.8 years, 49.5 % female). At both time points, three latent classes of tobacco and nicotine use behavior emerged (non-users, cigarette users, and poly-tobacco users). Intervention school students had 36 % lower odds of transitioning from cigarette use at baseline to poly-tobacco use at follow-up (OR = 0.64; 95 % CI 0.41,0.99, p = 0.047) compared to control school students. Males and younger students had increased odds of transitioning from cigarette use to poly-tobacco. In contrast, students of non-Danish origins had increased odds of transitioning from poly-tobacco use to non-use. Conclusions This study demonstrates the effectiveness of a smoking reduction intervention in reducing the progression toward poly-tobacco use among vocational school students.

Introduction: Understanding factors influencing the transition from non-use to tobacco and nicotine product initiation among adolescents is crucial for designing and implementing effective preventive strategies. This study explores transition patterns among 13-15-year-old adolescents in lower secondary school, focusing on the transition from non-use to tobacco and nicotine product initiation and the influence of individual, social, risk behavioral, and mental health factors on this transition. Methods: Based on data from a Danish smoking prevention trial between 2017 and 2019, this study employed questionnaire surveys at three time points: baseline (start of seventh grade, n = 1,990, response rate = 86.3%), eight-month follow-up (end of seventh grade, n = 1,666, response rate = 74,8%), and 20-month follow-up (end of eighth grade, n = 1,149, response rate = 70,6%). Tobacco and nicotine use indicators included current and lifetime use of cigarettes and lifetime use of e-cigarettes, smokeless tobacco, and hookah. A latent transition analysis was applied to identify longitudinal transition patterns across waves and to explore predictors of these patterns. Results: Three user classes emerged across all waves: none-use, lifetime e-cigarette and cigarette use, and polytobacco use. While the most prevalent class was the non-user class (71%-86%), the proportion of the lifetime e-cigarette and cigarette class increased over time (from 12% to 17%). Similarly, the poly-tobacco user class increased from 2% to 12%. The probability of transitioning from non-use to lifetime e-cigarette and cigarette use increased from 0.5% at baseline to 12% by the second follow-up, while the probability of transitioning from lifetime e-cigarette and cigarette use remained stable over time (12%-15%). Across all waves, elevated risk behavior predicted this transition. For instance, binge-drinking (OR = 3.76, 95% CI: 1.51-9.34), susceptibility to smoking (OR = 7.63, 95% CI: 3.68-16.83), and truancy (OR = 7.00, 95% CI: 1.98-24.59) influenced the transition from non-use at baseline to lifetime e-cigarette and cigarette use at first follow-up. Additionally, boys, adolescents with low socioeconomic status, low life satisfaction, and those with smoking friends or parents were more likely to transition from non-use to lifetime e-cigarette and cigarette use. Conclusion: This study demonstrates that sociodemographic, social risk, behavioral, and mental health factors impact the transition from non-use to lifetime e-cigarette and cigarette use. The findings provide valuable insights for developing targeted preventive strategies focusing on these influencing factors.

Despite much attention on digital media use and young peoples' sleep, the literature on digital media and its impact on sleep in older adolescents and young adults remains to be synthesized. We conducted a systematic review of studies including young people aged 16-25 years. We searched Medline, Web of Science, and CINAHL for observational studies, identifying 60 studies. These studies were assessed for methodological quality. Only studies rated as moderate or high-quality studies were included (n 1/4 42). A narrative synthesis summarized the impact of digital media use on eight sleep outcomes: Bedtime; Sleep onset latency or problems falling asleep; Sleep duration; Early awakening; Sleep disturbance; Daytime tiredness and function; Sleep deficits; Sleep quality. In summary, digital media use was associated to shorter sleep duration and poorer sleep quality. These associations were found for general screen use and use of mobile phone, computer, internet, and social media, but not for television, game console, and tablet use. Most studies investigating bedtime or nighttime use found associations to poor sleep outcomes. Later bedtime and daytime tiredness were associated with mobile phone use at night. Additional research is warranted to draw solid conclusions about the causal direction and to understand the underlying mechanisms. (c) 2023 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Abstract Background Distinct use patterns of tobacco and nicotine products are evolving among young people, notably after the market expansion of today's products. This study aims to identify and characterize subgroups of distinct tobacco and nicotine use patterns and to determine how a smoking reduction intervention and sociodemographic factors affected the transition patterns. Methods Data were from a Danish smoking reduction intervention targeting vocational school students. A latent transition analysis (LTA) was applied to identify patterns in latent classes of tobacco and nicotine use (use of cigarettes, smokeless tobacco, e-cigarettes, and hookah) from baseline to follow-up and to evaluate intervention effects on these patterns. Results A total of 2,158 students completed baseline and/or follow-up (FU) surveys (mean age = 20.8 years, 49.5% female). Three classes were identified: non-users (baseline: 31.3%, FU:33.9%), cigarette users (baseline: 36.0%, FU: 38.2%), and poly-users (baseline:33.7%, FU:27.9%). Students at intervention schools had 36% lower odds of transitioning from cigarette use at baseline to poly-use at follow-up (OR = 0.64; 0.41-0.99, p = 0.047) than control school students. Male and younger students were more likely to transition from cigarette use to poly-use. In contrast, students with origins other than Danish were more likely to transition from poly-use to non-use. Conclusions Intervention efforts must address tobacco and nicotine use progression towards high-risk use patterns, targeting those at greater risk of these progressions, such as males and younger students. Future research could benefit from using the LTA approach when evaluating intervention effects. Key messages • Three distinct latent nicotine and tobacco use classes emerged among Danish young adults attending vocational schools: non-use, mainly smoking, and poly-use. • Students at intervention schools had lower odds of transitioning from cigarette use at baseline to poly-use at follow-up than control school students.

Background Social inequality in smoking remains an important public health issue. Upper secondary schools offering vocational education and training (VET) comprise more students from lower socioeconomic backgrounds and have higher smoking prevalence than general high schools. This study examined the effects of a school-based multi-component intervention on students’ smoking. Methods A cluster randomized controlled trial. Eligible participants were schools offering VET basic courses or preparatory basic education in Denmark, and their students. Schools were stratified by subject area and eight schools were randomly allocated to intervention (1,160 invited students; 844 analyzed) and six schools to control (1,093 invited students; 815 analyzed). The intervention program comprised smoke-free school hours, class-based activities, and access to smoking cessation support. The control group was encouraged to continue with normal practice. Primary outcomes were daily cigarette consumption and daily smoking status at student level. Secondary outcomes were determinants expected to impact smoking behavior. Outcomes were assessed in students at five-month follow-up. Analyses were by intention-to-treat and per protocol (i.e., whether the intervention was delivered as intended), adjusted for covariates measured at baseline. Moreover, subgroup analyses defined by school type, gender, age, and smoking status at baseline were performed. Multilevel regression models were used to account for the cluster design. Missing data were imputed using multiple imputations. Participants and the research team were not blinded to allocation. Results Intention-to-treat analyses showed no intervention effect on daily cigarette consumption and daily smoking. Pre-planned subgroup analyses showed statistically significant reduction in daily smoking among girls compared with their counterparts in the control group (OR = 0.39, 95% CI: 0.16, 0.98). Per-protocol analysis suggested that schools with full intervention had higher benefits compared with the control group (daily smoking: OR = 0.44, 95% CI: 0.19, 1.02), while no marked differences were seen among schools with partial intervention. Conclusion This study was among the first to test whether a complex, multicomponent intervention could reduce smoking in schools with high smoking risk. Results showed no overall effects. There is a great need to develop programs for this target group and it is important that they are fully implemented if an effect is to be achieved. Trial registration https://www.isrctn.com/ISRCTN16455577 , date of registration 14/06/2018.

Many young adolescents experiment with substance use which can have substantial health implications later in life. This study examined trends in substance use among Danish adolescents from 2002 to 2018, including exclusive and dual current use of alcohol and cigarettes. Data on 13- and 15-year-olds (N = 15,295) from five comparable cross-sectional Health Behavior in School-aged Children (HBSC) surveys were used. Cochran-Armitage test for trend assessed the development in substance use patterns over time. Overall, a decreasing trend in current use of alcohol and cigarettes was found among Danish adolescents during the 16-year study period: from 71.7% in 2002 to 51.6% in 2018. In 2018, most adolescents (41.8%) currently used alcohol exclusively, 8.6% had a dual current use of cigarettes and alcohol, and 1.3% smoked cigarettes exclusively. Trends in alcohol use differed according to age groups, while no gender-specific trends in substance use were found. Findings suggest that a significant prevention potential in adolescent substance use remains, and future initiatives may focus on dual use of substances as well as tailored efforts to specific subgroups in high risk of using substances.

PURPOSE:While smoking is declining among young people, smokeless tobacco use is increasing. Identifying who is using smokeless tobacco and why is essential in preventing smokeless tobacco use. This study aimed to comprehensively explore the factors of young people's use of smokeless tobacco in western countries and identify research gaps. METHODS:We conducted a systematic scoping review of studies that examined factors associated with smokeless tobacco use among young people (ages 13-29) from western countries published between January 2011 and September 2021. Searches were conducted in CINAHL, Medline, and Scopus. Studies on adults, total tobacco use (i.e., did not differentiate between tobacco product types), dual and multiple uses of tobacco, and studies on smokeless tobacco cessation programs were excluded. RESULTS:A total of 160 studies were included in this scoping review. The studies were primarily undertaken in the US and the Scandinavian countries, and the majority explored smokeless tobacco use without distinguishing between the specific types. Smokeless tobacco users were more likely to be male, non-Hispanic white, engaging in physical activity, and using other substances, including cigarettes and alcohol. The role of friends and family were identified as critical factors that were related to the use of smokeless tobacco. CONCLUSIONS:This scoping review suggests that preventative measures against smokeless tobacco use should focus on peer and family members' roles and that these measures may benefit from targeting males. Additional research, including systematic reviews on this area to validate the identified associated factors, would improve the understanding of smokeless tobacco use.

Background Sleep is essential for child and adolescent health and well-being. There is an increasing interest in whether electronic media use affects children and young adolescents’ sleep. Prior reviews have focused on a school-aged population. Moreover, it is crucial that research continuously addresses the processes of technology and media use and the implication on sleep. This systematic review examines the evidence of electronic media use related to sleep among 0–15-year-olds. Methods Searches were carried out in four databases (CINAHL, Web of Science, EMBASE, and Medline). Inclusion criteria included age ≤ 15 years, and intervention, cohort, or cross-sectional studies from western countries. Methodological quality was rated using the Quality Assessment Tool for Quantitative Studies by two independent reviewers. Data was extracted using a standardized data extraction form. Synthesis was done by summarizing results across studies by age groups of 0–5, 6–12, and 13–15 years within four sleep domains: Bedtime and sleep onset; Sleep quality; Sleep duration; Daytime tiredness. Results The search identified 10,719 unique studies, of which 109 fulfilled inclusion and exclusion criteria and were assessed for methodological quality. In total, 49 studies were included in the review. The study designs were randomized controlled trials ( n = 3), quasi-experimental studies ( n = 2), prospective cohort studies ( n = 15), and cross-sectional studies ( n = 29). Evidence for an association between electronic media use and sleep duration was identified, with stronger evidence for 6–15-years-olds than 0–5-year-olds. The evidence for a relationship between electronic media use and other sleep outcomes was more inconclusive. However, for 6–12-year-old children, there was evidence for associations of electronic media use with delayed bedtime and poor sleep quality. For 13–15-year-olds, there was evidence for associations between screen time and problems falling asleep, and between social media use and poor sleep quality. Conclusions Overall, electronic media use was generally associated with shorter sleep duration in children and adolescents. Studies with stronger research design and of higher quality are needed to draw solid conclusions about electronic media’s impact on other sleep outcomes. Public awareness and interventions could be promoted about the potential negative impact on children’s sleep of electronic media devices that are used excessively and close to bedtime.

Aims: There are well-known gender differences in smoking, including the pattern of use and the effectiveness of smoking prevention programs. However, little is known about the differences between boys and girls in their attitudes towards smoking prevention interventions. This study explores gender differences in attitudes towards a school-based intervention to prevent smoking. Methods: We used data from the X:IT II intervention study conducted in 46 Danish elementary schools. Results: Compared to boys, girls were more positive towards smoke-free school time, both concerning rules for teachers smoking (odds ratio (OR) = 1.69, 95% confidence interval (CI): 1.35–2.12) and for students smoking (OR = 1.41, 95% CI: 1.13–1.76). No difference was observed in students signing the smoke-free agreement. However, a larger proportion of girls reported that the agreement was a good occasion to talk about smoking with their parents (OR = 1.36, 95% CI: 1.13–1.76). Girls were also more positive towards the smoke-free curriculum (OR = 1.52, 95% CI: 1.19–1.94). Conclusions: This study showed that girls were, overall, more positive towards the components of the smoking preventive intervention. Our findings highlight the importance of considering differences in intervention preferences for boys and girls in future health prevention initiatives.

Aims: We examined characteristics (smoking in social relations, binge drinking, and well-being measures) of Danish 13-year-olds in relation to their tobacco use patterns. Ever use of cigarettes exclusively, ever use of alternative tobacco products (ATPs; e-cigarettes, snus, or waterpipe) exclusively, and use of both cigarettes and ATPs were studied. Methods: We used self-reported data from students at 46 Danish schools in 2017 comprising 2,307 students (response rate = 86%). Multi-level logistic regression analyses were used to examine the associations between student characteristics and the odds for having ever used any tobacco products, smoked cigarettes exclusively, used ATPs exclusively, or used both cigarettes and ATPs compared with never use of any tobacco products. Unadjusted estimates and estimates adjusted for gender were reported. Results: A significant minority of youth (13.2%) had used one or more tobacco products. Of these, 2.0% had exclusively smoked cigarettes, 7.2% had exclusively used ATPs, and 4.0% had used both. Findings showed that all included characteristics (families' and friends' smoking, binge drinking, and well-being characteristics) were associated with using any tobacco product; however, students with friends who smoked, had been binge drinking, and had low well-being at home had notably higher odds for having both smoked cigarettes and used ATPs compared to the other tobacco use patterns. Conclusion: ATPs were popular among Danish adolescents compared with conventional cigarettes. Thus, prevention efforts among adolescents should not merely focus on the health risks of conventional cigarette smoking but also on ATPs. Students with diverse tobacco use patterns were similar on various characteristics. However, findings indicate that adolescents who had used both conventional cigarettes and ATPs constitute a more risk-averse group in special need of prevention efforts. Gender did not markedly influence the results. These findings may help future strategies aiming at the youngest adolescents at risk of using tobacco products.

Aims: Socio-economic inequalities in health behaviour may be influenced by health interventions. We examined whether the X:IT II intervention, aiming at preventing smoking in adolescence, was equally effective among students from different occupational social classes (OSC). Methods: We used data from the multi-component school-based smoking preventive intervention X:IT II, targeting 13- to 15-year-olds in Denmark. The intervention was tested in 46 schools with 2307 eligible students at baseline (response rate=86.6%) and had three main intervention components: smoke-free school time, smoke-free curriculum and parental involvement. We used a difference-in-difference design and estimated the change in current smoking after the first year of implementation in high versus low OSC. Analyses were based on available cases (N=1190) and imputation of missing data at follow-up (N=1967). Results: We found that 1% of the students from high OSC and 4.9% from low OSC were smokers at baseline (imputed data), and 8.2% of the students from high OSC and 12.2% from low OSC were smokers at follow-up. Difference-in-difference estimates were close to zero, indicating no differential trajectory. Conclusions: As intended, the X:IT II intervention, designed to apply equally to students from all socio-economic groups, did not seem to create different trajectories in current smoking among adolescents in high and low socio-economic groups. To diminish social inequality in health, future studies should carefully consider the ability to affect all socio-economic groups equally, or even to appeal mainly to participants from lower socio-economic groups, as they are often the ones most in need of intervention.

Objective: We examined whether schools participating in a school-based smoking prevention intervention (X:IT II) differed from other schools in Denmark. Methods: We used national data to compare schools in X:IT II (N = 46) to all other schools nationwide having a 7th grade (N = 1299). Using binary logistic regression analyses, we examined whether school characteristics and measures of pupils' well-being were associated with participation. Results: We found lower odds for participating in X:IT II among private schools compared to public schools (OR = .433, p = .026) and higher odds for participating among schools with many pupils reporting high social well-being (OR = 1.034, p = .023) and low well-being concerning support and inspiration (OR = 1.055, p = .019). Conclusions: Findings suggest that schools in X:IT II are representative in terms of pupil enrollment, proportion of pupils with foreign origin, organizational resources, average grades, academic well-being, and well-being concerning peace and order compared to schools nationwide. On the other hand, type of institution (private vs public), social well-being, and well-being concerning support and inspiration were significantly associated with participation in the intervention. These findings are relevant for guiding future interventions targeting health areas among school children and adolescents.

Background: The aim of the present study was to conduct a systematic review to identify documented mental health promotion interventions developed and tested among population-based older adults. Methods: A systematic review based on PRISMA guidelines. The literature was searched in PsycINFO and PubMed between June and September 2016. The Effective Public Health Practice Project tool was used to assess the quality of the included study. Results: In total 53 randomized controlled trial studies qualified for the systematic review. Across studies, three types of common conceptual themes emerged for interventions, including: 1) individual characteristics; 2) content and structure of the interventions; and 3) implementation of the interventions. Conclusions: No specific interventions could be recommended on the aforementioned basis. We conclude that a number of factors are of central importance for an intervention to have the desired effect. If these factors are considered, mental health can be successfully promoted among older adults.