Real-Life Effectiveness of Smoking Cessation Delivery Modes: A Comparison Against Telephone Counseling and the Role of Individual Characteristics and Health Conditions in Quit Success.

INTRODUCTION: Professional behavioral counseling for smoking cessation can be delivered in many forms, which may not work equally well for everyone. We aim to explore in a real-world setting whether different delivery modes yield different rates of quit success and whether quit success varies based on gender, age, educational level, and being treated for a health condition. AIMS AND METHODS: We used monitoring data (n = 13 747) from a smoking cessation counseling provider in the Netherlands (September 2018 to August 2021) to compare differences in quit success immediately after the end of counseling and at 12-month follow-up between telephone and other modes of counseling. Participants chose which mode of counseling they received. At the 12-month follow-up, we also examined differences in quit success based on demographic characteristics and whether one is being treated for various health conditions. RESULTS: Participants of in-person group counseling and online in-company group counseling were significantly more likely to have quit immediately after the counseling compared with telephone counseling (OR = 1.25, 95% CI = 1.08-1.44; OR = 1.63, 95% CI = 1.18-2.24). Analyses revealed no significant differences in quit success between telephone and other modes of counseling after 12 months. Those treated for a respiratory or psychological condition were less likely to have maintained quit success, as were women, and participants with a lower educational level. CONCLUSIONS: When chosen by oneself, the mode of smoking cessation counseling received does not appear to be important for long-term quit success. However, certain groups warrant extra support to prevent excessive program attrition and unsuccessful quit attempts. IMPLICATIONS: Our findings suggest that when chosen by oneself, the delivery mode of smoking cessation counseling does not appear to be important for long-term quit success. This finding is of particular relevance for those who are unable to attend in-person cessation counseling due to, for instance, reduced accessibility or mobility. We also found that women, lower educated, and younger participants were more likely to dropout of the cessation program or to not have maintained a quit attempt, signaling that disparities in smoking cessation persist when standardized counseling is given, and therefore more tailored counseling may be necessary for these groups.

Trends in Individualized Affordability of Factory-Made Cigarettes: Findings of the 2008-2020 International Tobacco Control Netherlands Surveys.

INTRODUCTION: Cigarette affordability, the price of tobacco relative to consumer income, is a key determinant of tobacco consumption. AIMS AND METHODS: This study examined trends over 12 years in individualized factory-made cigarette affordability in the Netherlands, and whether these trends differed by sex, age, and education. Data from 10 waves (2008-2020) of the International Tobacco Control Netherlands Surveys were used to estimate individualized affordability, measured as the percentage of income required to buy 100 cigarette packs (Relative Income Price [RIP]), using self-reported prices and income. The higher the RIP, the less affordable cigarettes are. Generalized estimating equation regression models assessed trends in individualized affordability over time and by sex, age, and education. RESULTS: Affordability decreased significantly between 2008 and 2020, with RIP increasing from 1.89% (2008) to 2.64% (2020) (p ≤ .001), except for 2008-2010, no significant year-on-year changes in affordability were found. Lower affordability was found among subgroups who have a lower income level: Females (vs. males), 18-24 and 25-39-year-olds (vs. 55 years and over) and low or moderate-educated individuals (vs. highly educated). Interactions between wave and education (p = .007) were found, but not with sex (p = .653) or age (p = .295). A decreasing linear trend in affordability was found for moderately (p = .041) and high-educated (p = .025), but not for low-educated individuals (p = .149). CONCLUSIONS: Cigarettes in the Netherlands have become less affordable between 2008 and 2020, yet this was mostly because of the decrease in affordability between 2008 and 2010. There is a need for more significant increases in tax to further decrease affordability. IMPLICATIONS: Our findings suggest that cigarettes have become less affordable in the Netherlands between 2008 and 2020. But, this appears to be the result of a steep decrease in affordability between 2008 and 2010. Affordability was lower among groups who have on average lower incomes (females, young adults, and low- and moderate-educated individuals), and differences in trends across education levels could be explained by per capita income changes. Our individualized measure indicated lower affordability than published aggregate affordability estimations. Future tax increases should be large enough to result in a lower affordability.

Exploring the gateway hypothesis of e-cigarettes and tobacco: a prospective replication study among adolescents in the Netherlands and Flanders.

BACKGROUND: Studies demonstrated that adolescent e-cigarette use is associated with subsequent tobacco smoking, commonly referred to as the gateway effect. However, most studies only investigated gateways from e-cigarettes to tobacco smoking. This study replicates a cornerstone study revealing a positive association between both adolescent e-cigarette use and subsequent tobacco use; and tobacco and subsequent e-cigarette use in the Netherlands and Flanders. DESIGN: The longitudinal design included baseline (n=2839) and 6-month (n=1276) and 12-month (n=1025) follow-up surveys among a school-based cohort (mean age: 13.62). Ten high schools were recruited as a convenience sample. The analyses involved (1) associations of baseline e-cigarette use and subsequent tobacco smoking among never smokers; (2) associations of e-cigarette use frequency at baseline and tobacco smoking frequency at follow-up; and (3) the association of baseline tobacco smoking and subsequent e-cigarette use among non-users of e-cigarettes. FINDINGS: Consistent with prior findings, baseline e-cigarette use was associated with higher odds of tobacco smoking at 6-month (OR=1.89; 95% CI 1.05 to 3.37) and 12-month (OR=5.63; 95% CI 3.04 to 10.42) follow-ups. More frequent use of e-cigarettes at baseline was associated with more frequent smoking at follow-ups. Baseline tobacco smoking was associated with subsequent e-cigarette use (OR=3.10; 95% CI 1.58 to 6.06 at both follow-ups). CONCLUSION: Our study replicated the positive relation between e-cigarette use and tobacco smoking in both directions for adolescents. This may mean that the gateway works in two directions, that e-cigarette and tobacco use share common risk factors, or that both mechanisms apply.

Smokers' strategies to reduce tobacco spending: self-reported use and differences across subgroups. Findings from the International Tobacco Control (ITC) Netherlands Survey.

BACKGROUND: The cost of tobacco is one of the most reported reasons for smoking cessation. Rather than quitting, smokers can use also strategies to reduce tobacco expenditure while continuing smoking, such as smoking less or using price-minimising strategies. The Netherlands announced to increase the price of a pack cigarettes from seven (2018) to ten euros (2023), to reduce tobacco prevalence and consumption. This study explores the self-reported strategies to reduce tobacco spending among Dutch smokers, and whether this differed per age, income, and education. Additionally, we analysed among quitters in these subgroups whether price played a role in their decision to quit. METHODS: Cross-sectional survey data from the International Tobacco Control (ITC) Netherlands Wave 2 (September-November 2020, N = 1915) was used. Strategies to reduce spending among smokers (N = 1790) were: reducing consumption, bulk buying, switching to cheaper products or buying from low-taxed sources. These were collapsed into: reducing consumption (solely or in combination with other behaviours), solely price-minimising behaviours (such as buying cheaper brands), or no strategies to reduce spending. Associations between strategies and characteristics were analysed through multinomial and binary logistic regression models. Second, we explored which subgroups were more likely to report that price played a role in their decision to quit among quitters (N = 125). RESULTS: The majority of smokers used strategies to reduce tobacco spending: 35.6% reduced consumption and 19.3% used solely price-minimising strategies. 82.1% of quitters reported that price played a role in their decision to quit. Low-income individuals were more likely to report price as a reason for quitting and reduce consumption, but also to buy cheaper products. Highly nicotine dependent smokers were more likely to use price-minimising behaviours, and less likely to reduce consumption. CONCLUSIONS: The majority reported using strategies to reduce spending or that price played a role in their decision to quit. Reducing consumption was the most reported strategy. Low-income smokers were more likely to reportedly reduce consumption, buy cheaper products, or quit. Price policies have the potential to reduce socioeconomic inequalities in smoking. To discourage price-minimising behaviours, such as switching to cheaper products, reducing price differences between products should be prioritized.

Demand for Factory-Made Cigarettes and Roll-Your-Own Tobacco and Differences Between Age and Socioeconomic Groups: Findings From the International Tobacco Control Netherlands Survey.

INTRODUCTION: Macroeconomic studies have shown that young individuals who smoke, and have a low socioeconomic status respond more strongly to price increases. Most of this evidence stems from research on factory-made (FM) cigarettes. With the rising popularity of roll-your-own (RYO) tobacco, there is a need for studies on cigarette demand that distinguish between both. AIMS AND METHODS: This study examined whether individual demand differed for FM and RYO tobacco, and across age, and socioeconomic (income and education) groups. Purchase tasks for FM and RYO cigarettes were included in the 2020 International Tobacco Control (ITC) Netherlands Survey. Adults who smoke daily (n = 1620) stated how many cigarettes they would smoke in 24 hours across eight prices. Four demand indices were derived: intensity (consumption at zero costs), alpha (rate of change in elasticity), Pmax (turning point elasticity), and breakpoint (lowest price where consumption equals zero). The indices were tested for subgroup differences. RESULTS: Individuals who smoke RYO tobacco indicated higher intensity, and greater alpha than individuals who smoke FM cigarettes. Participants aged 25-39 had lower Pmax, and 18-24 year olds displayed higher breakpoints. Participants with low income displayed higher intensity, and lower Pmax than other income groups. No associations were found with education. CONCLUSIONS: Individuals who smoke RYO tobacco indicated higher price sensitivity than those smoking FM cigarettes, supporting the need to harmonize tobacco taxation. Taxation may be especially beneficial to reducing consumption among individuals with a low income or smoke RYO tobacco. Substantially higher prices are needed in the Netherlands to achieve the desired results. IMPLICATIONS: Individuals who smoke daily were willing to pay substantially higher prices than the current market prices, indicating the room and need for much higher taxation levels. Demand for RYO tobacco was more sensitive to price changes than demand for FM cigarettes. Taxation should be raised at equivalent rates for FM and RYO cigarettes. Taxation appears to be especially effective in reducing consumption among people who smoke RYO tobacco and low-income individuals. It remains important to combine increased taxation with other tobacco control measures.

Price minimizing behaviours by smokers in Europe (2006-20): evidence from the International Tobacco Control Project.

BACKGROUND: Effectiveness of tobacco taxation can be undermined through smokers applying price-minimizing behaviours rather than quitting or reducing consumption. Common price-minimizing strategies are buying cheaper tobacco [discount brands or roll-your-own (RYO) tobacco], bulk buying and cross-border purchasing. This study analyses trends in and factors associated with such behaviours in four European countries from 2006 to 2020. METHODS: Data came from adult smokers participating in the International Tobacco Control (ITC) Surveys conducted between 2006 and 2020 in England (9 waves, n = 768-4149), France (4 waves, n = 1415-1735), Germany (5 waves, n = 513-1515) and the Netherlands (10 waves, n = 1191-2177). Country-specific generalized estimating equation regression models were fit to assess trends in smoking RYO tobacco, discount brands, bulk buying and cross-border purchasing within the European Union. RESULTS: Buying discount brands or RYO tobacco was the most common strategy in all countries, except France. Except for buying discount brands, estimates of price-minimizing behaviours were highest in France (2019: RYO = 27.2%, discount brands = 17.3%, bulk buying = 34.1%, cross-border purchasing = 34.2%), and lowest in Germany (2018: RYO = 18.6%, discount brands = 43.7%, bulk buying = 8.0%, cross-border purchasing = 9.8%). Direction and magnitude of trends differed by country, and behaviour. Young smokers were less likely to buy in bulk. Low-income and low-education smokers were more likely to purchase RYO tobacco or discount brands. The association with discount brands was not found for French low-income smokers. CONCLUSIONS: Smoking cheaper tobacco is the most prevalent price-minimizing strategy in three countries (England, Germany and Netherlands), and more prevalent among low-income individuals. Harmonizing prices across products and countries would reduce switching to cheaper tobacco.

How Financial Incentives Increase Smoking Cessation: A Two-Level Path Analysis.

INTRODUCTION: Financial incentives effectively increase smoking cessation rates, but it is unclear via which psychological mechanisms incentives influence quit behavior. The current study examines how receiving financial incentives for smoking cessation leads to quitting smoking and investigates several mediators and moderators of that relationship. AIMS AND METHODS: The study sample consisted of 604 tobacco-smoking employees from 61 companies in the Netherlands who completed a baseline and follow-up questionnaire. The current study is a secondary analysis from a cluster randomized trial where employees received smoking cessation group counseling at the workplace. Participants in the intervention group additionally received financial incentives of €350 in total for 12-month continuous smoking abstinence. We used a two-level path analysis to test a model that assesses the effects of financial incentives through smoking cessation program evaluation, medication use, nicotine replacement use, attitudes, self-efficacy, and social influences on quit success. We additionally tested whether an individual's reward responsiveness moderated the influence of incentives on quit success. RESULTS: The effect of financial incentives on quit success was mediated by a higher self-efficacy. Financial incentives were also associated with a higher use of cessation medication. A more positive program evaluation was related to higher self-efficacy, more social influence to quit, and more positive attitudes about quitting. The results did not differ significantly by individual reward responsiveness. CONCLUSIONS: The results of the current study suggest that financial incentives may be used to increase medication use and self-efficacy for quitting smoking, which offers an indirect way to increase successful smoking cessation. IMPLICATIONS: (1) This is the first study investigating via which psychological pathways financial incentives for quitting smoking can lead to long-term quit success. (2) The results showed a path between financial incentives and a higher likelihood of medication use. Incentives may encourage smokers to use medication in order to increase their chance of quitting smoking and receive the reward. (3) There was a path from financial incentives to quit success via a higher self-efficacy. (4) The effects of financial incentives did not depend on individual reward responsiveness.

Moral distress and ethical climate in intensive care medicine during COVID-19: a nationwide study.

BACKGROUND: The COVID-19 pandemic has created ethical challenges for intensive care unit (ICU) professionals, potentially causing moral distress. This study explored the levels and causes of moral distress and the ethical climate in Dutch ICUs during COVID-19. METHODS: An extended version of the Measurement of Moral Distress for Healthcare Professionals (MMD-HP) and Ethical Decision Making Climate Questionnaire (EDMCQ) were online distributed among all 84 ICUs. Moral distress scores in nurses and intensivists were compared with the historical control group one year before COVID-19. RESULTS: Three hundred forty-five nurses (70.7%), 40 intensivists (8.2%), and 103 supporting staff (21.1%) completed the survey. Moral distress levels were higher for nurses than supporting staff. Moral distress levels in intensivists did not differ significantly from those of nurses and supporting staff. "Inadequate emotional support for patients and their families" was the highest-ranked cause of moral distress for all groups of professionals. Of all factors, all professions rated the ethical climate most positively regarding the culture of mutual respect,  ethical awareness and support. "Culture of not avoiding end-of-life-decisions" and "Self-reflective and empowering leadership" received the lowest mean scores. Moral distress scores during COVID-19 were significantly lower for ICU nurses (p < 0.001) and intensivists (p < 0.05) compared to one year prior. CONCLUSION: Levels and causes of moral distress vary between ICU professionals and differ from the historical control group. Targeted interventions that address moral distress during a crisis are desirable to improve the mental health and retention of ICU professionals and the quality of patient care.

Factors associated with primary health care providers' alcohol screening behavior in Colombia, Mexico and Peru.

Background: Screening for unhealthy alcohol use in routine consultations can aid primary health care (PHC) providers in detecting patients with hazardous or harmful consumption and providing them with appropriate care. As part of larger trial testing strategies to improve implementation of alcohol screening in PHC, this study investigated the motivational (role security, therapeutic commitment, self-efficacy) and organizational context (leadership, work culture, resources, monitoring, community engagement) factors that were associated with the proportion of adult patients screened with AUDIT-C by PHC providers in Colombia, Mexico and Peru. Additionally, the study investigated whether the effect of the factors interacted with implementation strategies and the country. Methods: Pen-and-paper questionnaires were completed by 386 providers at the start of their study participation (79% female, Mage = 39.5, 37.6% doctors, 15.0% nurses, 9.6% psychologists, 37.8% other professional roles). They were allocated to one of four intervention arms: control group; short training only; short training in presence of municipal support; and standard (long) training in presence of municipal support. Providers documented their screening practice during the five-month implementation period. Data were collected between April 2019 and March 2020. Results: Negative binomial regression analysis found an inverse relationship of role security with the proportion of screened patients. Self-efficacy was associated with an increase in the proportion of screened patients only amongst Mexican providers. Support from leadership (formal leader in organization) was the only significant organizational context factor, but only in non-control arms. Conclusion: Higher self-efficacy is a relevant factor in settings where screening practice is already ongoing. Leadership support can enhance effects of implementation strategies.

Maximin design of cluster randomized trials with heterogeneous costs and variances.

Cluster randomized trials evaluate the effect of a treatment on persons nested within clusters, with clusters being randomly assigned to treatment. The optimal sample size at the cluster and person level depends on the study cost per cluster and per person, and the outcome variance at the cluster and the person level. The variances are unknown in the design stage and can differ between treatment arms. As a solution, this paper presents a Maximin design that maximizes the minimum relative efficiency (relative to the optimal design) over the variance parameter space, for trials with two treatment arms and a quantitative outcome. This maximin relative efficiency design (MMRED) is compared with a published Maximin design which maximizes the minimum efficiency (MMED). Both designs are also compared with the optimal designs for homogeneous costs and variances (balanced design) and heterogeneous costs and homogeneous variances (cost-conscious design), for a range of variances based upon three published trials. Whereas the MMED is balanced under high uncertainty about the treatment-to-control variance ratio, the MMRED then tends towards a balanced budget allocation between arms, leading to an unbalanced sample size allocation if costs are heterogeneous, similar to the cost-conscious design. Further, the MMRED corresponds to an optimal design for an intraclass correlation (ICC) in the lower half of the assumed ICC range (optimistic), whereas the MMED is the optimal design for the maximum ICC within the ICC range (pessimistic). Attention is given to the effect of the Welch-Satterthwaite degrees of freedom for treatment effect testing on the design efficiencies.

Relative efficiencies of two-stage sampling schemes for mean estimation in multilevel populations when cluster size is informative.

In multilevel populations, there are two types of population means of an outcome variable ie, the average of all individual outcomes ignoring cluster membership and the average of cluster-specific means. To estimate the first mean, individuals can be sampled directly with simple random sampling or with two-stage sampling (TSS), that is, sampling clusters first, and then individuals within the sampled clusters. When cluster size varies in the population, three TSS schemes can be considered, ie, sampling clusters with probability proportional to cluster size and then sampling the same number of individuals per cluster; sampling clusters with equal probability and then sampling the same percentage of individuals per cluster; and sampling clusters with equal probability and then sampling the same number of individuals per cluster. Unbiased estimation of the average of all individual outcomes is discussed under each sampling scheme assuming cluster size to be informative. Furthermore, the three TSS schemes are compared in terms of efficiency with each other and with simple random sampling under the constraint of a fixed total sample size. The relative efficiency of the sampling schemes is shown to vary across different cluster size distributions. However, sampling clusters with probability proportional to size is the most efficient TSS scheme for many cluster size distributions. Model-based and design-based inference are compared and are shown to give similar results. The results are applied to the distribution of high school size in Italy and the distribution of patient list size for general practices in England.

Efficient design of cluster randomized trials with treatment-dependent costs and treatment-dependent unknown variances.

Cluster randomized trials evaluate the effect of a treatment on persons nested within clusters, where treatment is randomly assigned to clusters. Current equations for the optimal sample size at the cluster and person level assume that the outcome variances and/or the study costs are known and homogeneous between treatment arms. This paper presents efficient yet robust designs for cluster randomized trials with treatment-dependent costs and treatment-dependent unknown variances, and compares these with 2 practical designs. First, the maximin design (MMD) is derived, which maximizes the minimum efficiency (minimizes the maximum sampling variance) of the treatment effect estimator over a range of treatment-to-control variance ratios. The MMD is then compared with the optimal design for homogeneous variances and costs (balanced design), and with that for homogeneous variances and treatment-dependent costs (cost-considered design). The results show that the balanced design is the MMD if the treatment-to control cost ratio is the same at both design levels (cluster, person) and within the range for the treatment-to-control variance ratio. It still is highly efficient and better than the cost-considered design if the cost ratio is within the range for the squared variance ratio. Outside that range, the cost-considered design is better and highly efficient, but it is not the MMD. An example shows sample size calculation for the MMD, and the computer code (SPSS and R) is provided as supplementary material. The MMD is recommended for trial planning if the study costs are treatment-dependent and homogeneity of variances cannot be assumed.

Efficient treatment allocation in 2 × 2 multicenter trials when costs and variances are heterogeneous.

At the design stage of a study, it is crucial to compute the sample size needed for treatment effect estimation with maximum precision and power. The optimal design depends on the costs, which may be known at the design stage, and on the outcome variances, which are unknown. A balanced design, optimal for homogeneous costs and variances, is typically used. An alternative to the balanced design is a design optimal for the known and possibly heterogeneous costs, and homogeneous variances, called costs considering design. Both designs suffer from loss of efficiency, compared with optimal designs for heterogeneous costs and variances. For 2 × 2 multicenter trials, we compute the relative efficiency of the balanced and the costs considering designs, relative to the optimal designs. We consider 2 heterogeneous costs and variance scenarios (in 1 scenario, 2 treatment conditions have small and 2 have large costs and variances; in the other scenario, 1 treatment condition has small, 2 have intermediate, and 1 has large costs and variances). Within these scenarios, we examine the relative efficiency of the balanced design and of the costs considering design as a function of the extents of heterogeneity of the costs and of the variances and of their congruence (congruent when the cheapest treatment has the smallest variance, incongruent when the cheapest treatment has the largest variance). We find that the costs considering design is generally more efficient than the balanced design, and we illustrate this theory on a 2 × 2 multicenter trial on lifestyle improvement of patients in general practices.

Construct and Predictive Validity of Three Measures of Intention to Quit Smoking: Findings From the International Tobacco Control (ITC) Netherlands Survey.

Introduction: The aim of the study was to compare the construct validity and the predictive validity of three instruments to measure intention to quit smoking: a Stages of Change measure, the Motivation To Stop Scale (MTSS), and a Likert scale. We used the Theory of Planned Behavior as theoretical framework. Methods: We used data from the International Tobacco Control Netherlands Survey. We included smokers who participated in three consecutive survey waves (n = 980). We measured attitude, subjective norm, and perceived behavioral control in 2012, intention to quit with three instruments in 2013, and having made a quit attempt in the last year in 2014. We conducted Structural Equation Modeling with three models for the instruments of intention separately and with one model that included the three instruments simultaneously. Results: All three instruments of intention were significantly and positively related to attitude and perceived behavioral control but none was related to subjective norm. All three instruments were significantly and positively related to making a quit attempt. The relation of the Likert scale with making a quit attempt (ß = 0.38) was somewhat stronger than that of the Stages of Change measure (ß = 0.35) and the MTSS (ß = 0.22). When entering the three instruments together into one model, only the Likert scale was significantly related to making a quit attempt. Conclusions: All three instruments showed reasonable construct validity and comparable predictive validity. Under the studied conditions, the Likert scale performed slightly better than the Stages of Change measure and the MTSS. Implications: An assessment of the Stages of Change, the Motivation To Stop Scale, and a Likert scale showed comparable predictive and construct validity as measures for intention to quit smoking. All three instruments can be used in future research; however, under the studied theoretical framework, that is, the Theory of Planned Behavior, the Likert scale performed slightly better than the other two instruments.

Support for a point-of-sale cigarette display ban among smokers: findings from the international tobacco control (ITC) Netherlands survey.

BACKGROUND: Displaying tobacco products at point-of-sale (PoS) has become an important marketing strategy for the tobacco industry. This study was designed to (1) examine how support for a PoS cigarette display ban changed among Dutch smokers between 2010 and 2015 and (2) identify the variables that predict support among smokers for a PoS cigarette display ban. METHODS: Longitudinal data from six annual survey waves (2010-2015) from the International Tobacco Control (ITC) Netherlands Survey were analyzed. The sample consisted of between 1279 and 1800 smokers per year. Smokers were asked whether they supported a complete ban on displays of cigarettes inside shops and stores. RESULTS: Support for a PoS cigarette display ban increased from 28.9% in 2010 to 42.5% in 2015 (OR = 1.40, p < 0.001). A multiple logistic regression analysis revealed that support for a PoS display ban of cigarettes was more likely among smokers who had more knowledge about the health risks of smoking (OR = 3.97, p < 0.001), believed smoking-related health risks to be severe (OR = 1.39, p < 0.001), had a more positive attitude towards quitting smoking (OR = 1.44, p = 0.006), reported stronger social norms to quit smoking (OR = 1.29, p = 0.035), had a higher self-efficacy for quitting smoking (OR = 1.31, p = 0.001), and had stronger intentions to quit smoking (OR = 1.23, p = 0.006). CONCLUSIONS: This paper showed that support for a PoS display ban of cigarettes increased among smokers in the Netherlands over the years. To further increase support, educational campaigns about the dangers of smoking, and campaigns that encourage quitting may be needed.

Repairing the efficiency loss due to varying cluster sizes in two-level two-armed randomized trials with heterogeneous clustering.

In two-armed trials with clustered observations the arms may differ in terms of (i) the intraclass correlation, (ii) the outcome variance, (iii) the average cluster size, and (iv) the number of clusters. For a linear mixed model analysis of the treatment effect, this paper examines the expected efficiency loss due to varying cluster sizes based upon the asymptotic relative efficiency of varying versus constant cluster sizes. Simple, but nearly cost-optimal, correction factors are derived for the numbers of clusters to repair this efficiency loss. In an extensive Monte Carlo simulation, the accuracy of the asymptotic relative efficiency and its Taylor approximation are examined for small sample sizes. Practical guidelines are derived to correct the numbers of clusters calculated under constant cluster sizes (within each treatment) when planning a study. Because of the variety of simulation conditions, these guidelines can be considered conservative but safe in many realistic situations. Copyright © 2016 John Wiley & Sons, Ltd.

Exploring individual cognitions, self-regulation skills, and environmental-level factors as mediating variables of two versions of a Web-based computer-tailored nutrition education intervention aimed at adults: A randomized controlled trial.

BACKGROUND: This study explored whether the determinants that were targeted in two versions of a Web-based computer-tailored nutrition education intervention mediated the effects on fruit, high-energy snack, and saturated fat intake among adults who did not comply with dietary guidelines. METHOD: A RCT was conducted with a basic (tailored intervention targeting individual cognitions and self-regulation), plus (additionally targeting environmental-level factors), and control group (generic nutrition information). Participants were recruited from the general Dutch adult population and randomly assigned to one of the study groups. Online self-reported questionnaires assessed dietary intake and potential mediating variables (behavior-specific cognitions, action- and coping planning, environmental-level factors) at baseline and one (T1) and four (T2) months post-intervention (i.e. four and seven months after baseline). The joint-significance test was used to establish mediating variables at different time points (T1-mediating variables - T2-intake; T1-mediating variables - T1-intake; T2-mediating variables - T2-intake). Educational differences were examined by testing interaction terms. RESULTS: The effect of the plus version on fruit intake was mediated (T2-T2) by intention and fruit availability at home and for high-educated participants also by attitude. Among low/moderate-educated participants, high-energy snack availability at home mediated (T1-T1) the effect of the basic version on high-energy snack intake. Subjective norm mediated (T1-T1) the effect of the basic version on fat intake among high-educated participants. DISCUSSION: Only some of the targeted determinants mediated the effects of both intervention versions on fruit, high-energy snack, and saturated fat intake. A possible reason for not finding a more pronounced pattern of mediating variables is that the educational content was tailored to individual characteristics and that participants only received feedback for relevant and not for all assessed mediating variables. TRIAL REGISTRATION: Netherlands Trial Registry NTR3396.

Effectiveness of a systematic approach to promote intersectoral collaboration in comprehensive school health promotion-a multiple-case study using quantitative and qualitative data.

BACKGROUND: We report on the longitudinal quantitative and qualitative data resulting from a two-year trajectory (2008-2011) based on the DIagnosis of Sustainable Collaboration (DISC) model. This trajectory aimed to support regional coordinators of comprehensive school health promotion (CSHP) in systematically developing change management and project management to establish intersectoral collaboration. METHODS: Multilevel analyses of quantitative data on the determinants of collaborations according to the DISC model were done, with 90 respondents (response 57 %) at pretest and 69 respondents (52 %) at posttest. Nvivo analyses of the qualitative data collected during the trajectory included minutes of monthly/bimonthly personal/telephone interviews (N = 65) with regional coordinators, and documents they produced about their activities. RESULTS: Quantitative data showed major improvements in change management and project management. There were also improvements in consensus development, commitment formation, formalization of the CSHP, and alignment of policies, although organizational problems within the collaboration increased. Content analyses of qualitative data identified five main management styles, including (1) facilitating active involvement of relevant parties; (2) informing collaborating parties; (3) controlling and (4) supporting their task accomplishment; and (5) coordinating the collaborative processes. CONCLUSIONS: We have contributed to the fundamental understanding of the development of intersectoral collaboration by combining qualitative and quantitative data. Our results support a systematic approach to intersectoral collaboration using the DISC model. They also suggest five main management styles to improve intersectoral collaboration in the initial stage. The outcomes are useful for health professionals involved in similar ventures.

Short- and medium-term efficacy of a Web-based computer-tailored nutrition education intervention for adults including cognitive and environmental feedback: randomized controlled trial.

BACKGROUND: Web-based, computer-tailored nutrition education interventions can be effective in modifying self-reported dietary behaviors. Traditional computer-tailored programs primarily targeted individual cognitions (knowledge, awareness, attitude, self-efficacy). Tailoring on additional variables such as self-regulation processes and environmental-level factors (the home food environment arrangement and perception of availability and prices of healthy food products in supermarkets) may improve efficacy and effect sizes (ES) of Web-based computer-tailored nutrition education interventions. OBJECTIVE: This study evaluated the short- and medium-term efficacy and educational differences in efficacy of a cognitive and environmental feedback version of a Web-based computer-tailored nutrition education intervention on self-reported fruit, vegetable, high-energy snack, and saturated fat intake compared to generic nutrition information in the total sample and among participants who did not comply with dietary guidelines (the risk groups). METHODS: A randomized controlled trial was conducted with a basic (tailored intervention targeting individual cognition and self-regulation processes; n=456), plus (basic intervention additionally targeting environmental-level factors; n=459), and control (generic nutrition information; n=434) group. Participants were recruited from the general population and randomly assigned to a study group. Self-reported fruit, vegetable, high-energy snack, and saturated fat intake were assessed at baseline and at 1- (T1) and 4-months (T2) postintervention using online questionnaires. Linear mixed model analyses examined group differences in change over time. Educational differences were examined with group×time×education interaction terms. RESULTS: In the total sample, the basic (T1: ES=-0.30; T2: ES=-0.18) and plus intervention groups (T1: ES=-0.29; T2: ES=-0.27) had larger decreases in high-energy snack intake than the control group. The basic version resulted in a larger decrease in saturated fat intake than the control intervention (T1: ES=-0.19; T2: ES=-0.17). In the risk groups, the basic version caused larger decreases in fat (T1: ES=-0.28; T2: ES=-0.28) and high-energy snack intake (T1: ES=-0.34; T2: ES=-0.20) than the control intervention. The plus version resulted in a larger increase in fruit (T1: ES=0.25; T2: ES=0.37) and a larger decrease in high-energy snack intake (T1: ES=-0.38; T2: ES=-0.32) than the control intervention. For high-energy snack intake, educational differences were found. Stratified analyses showed that the plus version was most effective for high-educated participants. CONCLUSIONS: Both intervention versions were more effective in improving some of the self-reported dietary behaviors than generic nutrition information, especially in the risk groups, among both higher- and lower-educated participants. For fruit intake, only the plus version was more effective than providing generic nutrition information. Although feasible, incorporating environmental-level information is time-consuming. Therefore, the basic version may be more feasible for further implementation, although inclusion of feedback on the arrangement of the home food environment and on availability and prices may be considered for fruit and, for high-educated people, for high-energy snack intake. TRIAL REGISTRATION: Netherlands Trial Registry NTR3396; http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=3396 (Archived by WebCite at http://www.webcitation.org/6VNZbdL6w).

Sample size calculation in cost-effectiveness cluster randomized trials: optimal and maximin approaches.

In this paper, the optimal sample sizes at the cluster and person levels for each of two treatment arms are obtained for cluster randomized trials where the cost-effectiveness of treatments on a continuous scale is studied. The optimal sample sizes maximize the efficiency or power for a given budget or minimize the budget for a given efficiency or power. Optimal sample sizes require information on the intra-cluster correlations (ICCs) for effects and costs, the correlations between costs and effects at individual and cluster levels, the ratio of the variance of effects translated into costs to the variance of the costs (the variance ratio), sampling and measuring costs, and the budget. When planning, a study information on the model parameters usually is not available. To overcome this local optimality problem, the current paper also presents maximin sample sizes. The maximin sample sizes turn out to be rather robust against misspecifying the correlation between costs and effects at the cluster and individual levels but may lose much efficiency when misspecifying the variance ratio. The robustness of the maximin sample sizes against misspecifying the ICCs depends on the variance ratio. The maximin sample sizes are robust under misspecification of the ICC for costs for realistic values of the variance ratio greater than one but not robust under misspecification of the ICC for effects. Finally, we show how to calculate optimal or maximin sample sizes that yield sufficient power for a test on the cost-effectiveness of an intervention.