The use of existing data sources to evaluate the impact of tobacco control policies on quitting behaviour

Background In England there is a comprehensive framework of tobacco control policies to reduce smoking-related harm. Policy evaluation helps to ascertain how policies may be improved so that they have the greatest impact; ineffective policies can be dropped or improved, while effective policies can be kept and improved further in order to optimise their impact. The evaluation of tobacco control policy requires high quality and timely data on smoking and smoking cessation behaviour. Time series analysis (TSA) is a robust way of evaluating policy, as it takes existing trends into account, but requires frequently collected data in large samples over long time periods. The aims of this thesis were to investigate the suitability of a range of existing data sources for evaluating the impact of tobacco control policies in England on quitting behaviour, validate potentially suitable measures, and use validated measures to evaluate the impact of recent tobacco control initiatives in England using TSA. Methods A range of data sources which provide information on smoking cessation behaviour were analysed to determine their adequacy for evaluating tobacco control policies, and previously unvalidated measures were validated. Different approaches to TSA – interrupted time series analysis and multiple time series analysis - were employed to evaluate the impact of the introduction of a new smoking cessation medication, varenicline, the broadening of the indications for nicotine replacement therapy (NRT) to include people with cardiovascular disease and adolescents, and the effect of anti-tobacco mass media campaigns on quitting behaviour. Results Two key indicators of quitting behaviour are quit attempts and smoking prevalence; however, there are currently no frequently collected data from large enough samples covering a long time period on these measures. Survey data are generally not suitable for policy evaluation because they are infrequently carried out and often have small sample sizes, making it difficult to detect small and transient changes in behaviour. In contrast, routine sources of data such as electronic medical records data are often frequently collected in large samples over long time periods. A validation study showed that primary care data from The Health Improvement Network are an accurate source of data on prescribing of smoking cessation medication. Time series analyses of these data showed that both the introduction of varenicline, and the broadening of the indications for NRT, did not increase rates of prescribing for smoking cessation medication. Another study found that tobacco control mass media campaigns appear to be more effective at triggering quitting behaviour than pharmaceutical company NRT campaigns. Conclusions Although there are significant gaps in the existing data available, there are some high quality time series data which can be used to evaluate the impact of tobacco control policies in England. There is a need for regular collection of data on key indicators of quitting behaviour, and the use of time series analysis in policy evaluation can play a vital role in strengthening the evidence for the effectiveness of policies, both in tobacco control, and in other areas of public health. The time series studies in this thesis suggest that recent changes to the availability of pharmacological smoking cessation aids have not had a significant impact on public health, and that recent cuts in tobacco control advertising are likely to have reduced quitting behaviour. .EThOS - Electronic Theses Online ServiceGBUnited Kingdo