Perceived effectiveness of tobacco packaging and cigarette stick warnings as anti-tobacco interventions

Introduction: Tobacco use remains the largest preventable cause of mortality in Australia, despite significant reductions in the prevalence of daily smoking over the past 25 years. Multiple public health interventions have contributed to these reductions, including health warnings and graphic images on cigarette packaging. Whilst initially effective in curbing tobacco use, recent research has identified that these packaging health warnings have become less effective as an anti-tobacco intervention. As tobacco is still the cause of death of an estimated 15 000 Australians per year, further improvements in anti-tobacco interventions are needed. A novel anti-tobacco medium being investigated is the cigarette stick itself. As the primary packaging of tobacco leaf used whilst smoking, it represents a logical and appropriate medium for communicating the consequences of smoking. This research first aimed to confirm recent findings suggesting that current cigarette packaging warnings have lost their effectiveness. It also evaluated the perceptions of a diverse participant cohort towards the use of cigarette sticks as a novel anti-tobacco intervention medium, and to inform on the development of warnings and messages effective both in preventing non-smokers from experimenting with cigarettes, and prompting current smokers to quit smoking. Methods: A mixed methods approach was utilised, incorporating the use of online surveys, and semi-structured focus groups and interviews. Established health warnings on current cigarette packaging, and novel warnings and messages on individual cigarette sticks were presented to a range of participants, including adolescents and young adults, pharmacists, an international cohort of current smokers, and the wider Australian community. The Health Belief Model (HBM) was utilised in developing the interventional materials. These materials aimed to increase readers' perceived susceptibility and severity of the negative consequences of tobacco use, whilst also outlining the benefits of not smoking, and acting as an additional prompt for quit attempts. A sequential explanatory design was used, where initial survey and focus group findings were triangulated and used to refine the health warnings and messages used in subsequent surveys, focus groups and interviews. Quantitative data on participants' perceived effectiveness of cigarette packaging and cigarette stick warnings were collected using 5-point Likert scales, and analysed using Chi squared and proportional odds logistic regression analyses. In-depth qualitative information was gathered to support and expand upon the quantitative data, achieved through free-text comments in the surveys, and from focus groups and interviews, which were analysed using content and thematic analyses respectively. Results and Discussion: A total of 2 045 participants were involved in the research, of which 75% were Australian, 60% were female, 37% were smokers, and 80% were of Caucasian descent. These participants were split amongst five primary populations: the wider Australian community (637), pharmacists (79), school students (150), university students (501), and an international cohort of smokers (678). Perceptions of the effectiveness of current cigarette packaging warnings were generally consistent amongst all participant groups. These warnings were considered minimally effective in prompting current smokers to quit, though slightly more effective in preventing non-smokers from experimenting with cigarettes. Analyses of the qualitative data identified several reasons for these poor ratings, including a loss of shock value due to repetitive exposure over several years, simply ignoring the packaging warnings, and a feeling that the warnings were irrelevant, particularly amongst the younger participants. In comparison, several of the novel warnings and messages on individual cigarette sticks were rated as significantly more effective than current packaging warnings in preventing nonsmokers from smoking, and prompting current smokers to quit. These warnings were considered particularly effective in increasing participants' perceived susceptibility and severity to a wider range of consequences of smoking, and outlining the benefits of not smoking. The financial costs of smoking was a message considered novel, engaging, and widely applicable to the broader population compared to current packaging warnings, particularly by current smokers (Odds Ratio [OR] = 3.42, 95% Confidence Interval [CI] 2.75- 4.25, p<.001). This was supported by the open-text comments, with participants indicating that financial stability is valued over avoiding potential health issues. Other warnings perceived as effective throughout this research in comparison to current packaging warnings include the 'minutes of life lost' per cigarette (OR = 3.60, 95% CI 2.79-4.64, p<.001 amongst university students), and the negative effects of smoking on family members (OR = 2.85, 95% CI 2.29- 3.55, p<.001 amongst current smokers). These warnings were considered novel, relatable, and engaging, making them capable of eliciting strong emotional responses likely to motivate changes in smoking behaviour amongst smokers, and prevent experimentation amongst nonsmokers. Participants were also in favour of the inclusion of warnings and messages on cigarette sticks, with over half (54%) of smokers and over three-quarters (87%) of non-smokers either 'agreeing' or 'strongly agreeing'. They believed that this anti-tobacco intervention would be more difficult to avoid, and would reduce the aesthetic appeal of smoking, particularly amongst adolescents. Conclusions: This research has confirmed shortcomings in the effectiveness of current cigarette packaging warnings, emphasising the need for improvements in anti-tobacco interventions. The inclusion of novel and engaging warnings and messages on individual cigarette sticks was found to be a potentially effective next step in combating the global tobacco epidemic. It is essential that these warnings are able to elicit strong reactions by persons of any age and smoking status. The vast majority of non-smokers, and over half of smokers were in support of this novel anti-tobacco intervention. Future warning and message development for both cigarette packaging and cigarette sticks should therefore include short-term health, and non-health related consequences of tobacco use, since in this research they were found to be the most engaging, and likely to elicit positive public health changes in the community

New Insights into History Matching via Sequential Monte Carlo

The aim of the history matching method is to locate non-implausible regions of the parameter space of complex deterministic or stochastic models by matching model outputs with data. It does this via a series of waves where at each wave an emulator is fitted to a small number of training samples. An implausibility measure is defined which takes into account the closeness of simulated and observed outputs as well as emulator uncertainty. As the waves progress, the emulator becomes more accurate so that training samples are more concentrated on promising regions of the space and poorer parts of the space are rejected with more confidence. Whilst history matching has proved to be useful, existing implementations are not fully automated and some ad-hoc choices are made during the process, which involves user intervention and is time consuming. This occurs especially when the non-implausible region becomes small and it is difficult to sample this space uniformly to generate new training points. In this article we develop a sequential Monte Carlo (SMC) algorithm for implementation which is semi-automated. Our novel SMC approach reveals that the history matching method yields a non-implausible distribution that can be multi-modal, highly irregular and very difficult to sample uniformly. Our SMC approach offers a much more reliable sampling of the non-implausible space, which requires additional computation compared to other approaches used in the literature

Unbiased and Consistent Nested Sampling via Sequential Monte Carlo

We introduce a new class of sequential Monte Carlo methods called Nested Sampling via Sequential Monte Carlo (NS-SMC), which reframes the Nested Sampling method of Skilling (2006) in terms of sequential Monte Carlo techniques. This new framework allows convergence results to be obtained in the setting when Markov chain Monte Carlo (MCMC) is used to produce new samples. An additional benefit is that marginal likelihood estimates are unbiased. In contrast to NS, the analysis of NS-SMC does not require the (unrealistic) assumption that the simulated samples be independent. As the original NS algorithm is a special case of NS-SMC, this provides insights as to why NS seems to produce accurate estimates despite a typical violation of its assumptions. For applications of NS-SMC, we give advice on tuning MCMC kernels in an automated manner via a preliminary pilot run, and present a new method for appropriately choosing the number of MCMC repeats at each iteration. Finally, a numerical study is conducted where the performance of NS-SMC and temperature-annealed SMC is compared on several challenging and realistic problems. MATLAB code for our experiments is made available at https://github.com/LeahPrice/SMC-NS .Comment: 45 pages, some minor typographical errors fixed since last versio

Evidence-based recommendations for medical management of Peripheral Artery Disease

Patients with lower limb artery stenosis or occlusion (peripheral artery disease; PAD) have been determined to be at very high risk of both major adverse cardiovascular events, such as myocardial infarction and stroke, and major adverse limb events, such as amputation and requirement for artery surgery. Effective medical management has been identified as key in reducing this risk; however, this is often poorly implemented in clinical practice. Thus, the aim of this narrative review was to summarize the current evidence on the medical management of PAD in order to inform clinicians and highlight recommendations for clinical practice. International guidelines, randomized controlled trials, and relevant systematic reviews and metaanalyses have been included in this study. The focus was the management of the key modifiable risk factors to mitigate possible adverse events through prescription of anti-platelet and anticoagulation drugs and medications to control low-density lipoprotein cholesterol, blood pressure, and diabetes and aid smoking cessation. The available evidence from randomized clinical trials provide a strong rationale for the need for holistic medical management programs that are effective in achieving uptake of these medical therapies in patients with PAD. In conclusion, people with PAD have some of the highest adverse event rates among those with cardiovascular diseases. Secondary preventive measures have been proven effective in reducing these adverse events; however, they remain to be adequately implemented. Thus, the need for an effective implementation program has emerged to reduce adverse events in this patient group

Pre-processing for approximate Bayesian computation in image analysis

Most of the existing algorithms for approximate Bayesian computation (ABC) assume that it is feasible to simulate pseudo-data from the model at each iteration. However, the computational cost of these simulations can be prohibitive for high dimensional data. An important example is the Potts model, which is commonly used in image analysis. Images encountered in real world applications can have millions of pixels, therefore scalability is a major concern. We apply ABC with a synthetic likelihood to the hidden Potts model with additive Gaussian noise. Using a pre-processing step, we fit a binding function to model the relationship between the model parameters and the synthetic likelihood parameters. Our numerical experiments demonstrate that the precomputed binding function dramatically improves the scalability of ABC, reducing the average runtime required for model fitting from 71 hours to only 7 minutes. We also illustrate the method by estimating the smoothing parameter for remotely sensed satellite imagery. Without precomputation, Bayesian inference is impractical for datasets of that scale.Comment: 5th IMS-ISBA joint meeting (MCMSki IV

Reactions to, and trial intentions for, three dissuasive cigarette designs:A cross-sectional survey of adolescents in Scotland

Objectives There has been growing academic and policy interest in opportunities to decrease the appeal of cigarette sticks, such as making them an unattractive colour or requiring them to display a health warning. We therefore explored reactions to, and trial intentions for, three ‘dissuasive’ cigarette designs among adolescents in Scotland. Methods A cross-sectional survey with 12–17 year olds in Scotland (n=594) was conducted between November 2017 and November 2018. Participants were shown one ‘standard’ cigarette (imitation cork filter with white paper casing) and three dissuasive cigarettes: (1) a cigarette with the warning ‘smoking kills’; (2) a cigarette with the warning ‘toxic’ and a skull and cross-bones image and (3) a dark green cigarette. Participants rated each cigarette on nine five-point reaction measures (eg, appealing/unappealing or attractive/unattractive). A composite reaction score was computed for each cigarette, which was binary coded (overall negative reactions vs neutral/positive reactions). Participants also indicated whether they would try each cigarette (coded: Yes/No). Demographics, smoking status and smoking susceptibility were also measured. Results More participants had negative reactions to the dark green (93% of adolescents), ‘smoking kills’ (94%) and ‘toxic’ (96%) cigarettes, compared with the standard cigarette (85%). For all three dissuasive designs, Chi-square tests found that negative reactions were more likely among younger adolescents (vs older adolescents), never-smokers (vs ever smokers) and non-susceptible never-smokers (vs susceptible never-smokers). Most participants indicated that they would not try any of the cigarettes (range: 84%–91%). Conclusion Dissuasive cigarettes present an opportunity to further reduce the appeal of smoking among adolescents