Linsay Gray

Background: E-cigarettes are a popular smoking-cessation tool. Although less harmful than tobacco, use of e-cigarettes by non-smokers should be prevented. There is concern about the use of e-cigarettes by young people and that e-cigarettes may renormalise smoking. In May 2016, Tobacco Products Directive regulations aimed to reduce e-cigarettes’ appeal to young people. Aims: To examine the effects of the Tobacco Products Directive regulations on young people’s use of e-cigarettes, and the role of e-cigarettes in renormalising smoking. Design: A mixed-method natural experimental evaluation combining secondary analyses of survey data, with process evaluation, including interviews with young people, policy stakeholders, retailers and trading standards observers, and observations of retail settings. Settings: Wales, Scotland and England. Participants: Survey participants were aged 13–15 years, living in England, Scotland or Wales and participated in routinely conducted surveys from 1998 to 2019. Process evaluation participants included 14- to 15-year-olds in England, Scotland and Wales, policy stakeholders, trading standards offices and retailers. Intervention: Regulation of e-cigarettes, including bans on cross-border advertising, health warnings and restrictions on product strength. Comparison group: Interrupted time series design, with baseline trends as the comparator. Main outcome measures: The primary outcome was ever e-cigarette use. Secondary outcomes included regular use, ever and regular smoking, smoking attitudes, alcohol and cannabis use. Data capture and analysis: Our primary statistical analysis used data from Wales, including 91,687 young people from the 2013–19 Health Behaviour in School-aged Children and School Health Research Network surveys. In Scotland, we used the Scottish Schools Adolescent Lifestyle and Substance Use Survey and in England we used the Smoking Drinking and Drug Use surveys. The process evaluation included interviews with 73 young people in 2017 and 148 young people in 2018, 12 policy stakeholders, 13 trading standards officers and 27 retailers. We observed 30 retail premises before and after implementation. Data were integrated using the Medical Research Council’s process evaluation framework. Results: Ever smoking continued to decline alongside the emergence of e-cigarettes, with a slight slowing in decline for regular use. Tobacco Products Directive regulations were described by stakeholders as well implemented, and observations indicated good compliance. Young people described e-cigarettes as a fad and indicated limited interaction with the components of the Tobacco Products Directive regulations. In primary statistical analyses in Wales [i.e. short (to 2017) and long term (to 2019)], growth in ever use of e-cigarettes prior to Tobacco Products Directive regulations did not continue after implementation. Change in trend was significant in long-term analysis, although of similar magnitude at both time points (odds ratio 0.96). Data from England and Scotland exhibited a similar pattern. Smoking followed the opposite pattern, declining prior to the Tobacco Products Directive regulations, but plateauing as growth in e-cigarette use stalled. Limitations: Alternative causal explanations for changes cannot be ruled out because of the observational design. Conclusions: Young people’s ever and regular use of e-cigarettes appears to have peaked around the time of the Tobacco Products Directive regulations and may be declining. Although caution is needed in causal attributions, findings are consistent with an effect of regulations. Our analysis provides little evidence that e-cigarettes renormalise smoking. More recent data indicate that declines in smoking are plateauing. Future work: International comparative work to understand differences in use of e-cigarettes, and tobacco, within varying regulatory frameworks is a priority. Study registration: This study is registered as ResearchRegistry4336. Funding: This project was funded by the National Institute for Health and Care Research (NIHR) Public Health Research programme and will be published in full in Public Health Research; Vol. 11, No. 5. See the NIHR Journals Library website for further project information.

It is becoming increasingly possible to obtain additional information about health survey participants, though not usually non-participants, via record linkage. We aimed to assess the validity of an assumption underpinning a method developed to mitigate non-participation bias. We use a survey in Finland where it is possible to link both participants and non-participants to administrative registers. Survey-derived alcohol consumption is used as the exemplar outcome. Data on participants (85.5%) and true non-participants of the Finnish Health 2000 survey (invited survey sample N=7167 aged 30-79 years) and a contemporaneous register-based population sample (N=496,079) were individually linked to alcohol-related hospitalisation and death records. Applying the methodology to create synthetic observations on non-participants, we created ‘inferred samples’ (participants and inferred non-participants). Relative differences (RDs) between the inferred sample and the invited survey sample were estimated overall and by education. Five per cent limits were used to define acceptable RDs. Average weekly consumption estimates for men were 129 g and 131 g of alcohol in inferred and invited survey samples, respectively (RD –1.6%; 95% confidence interval (CI) –2.2 to –0.04%) and 35 g for women in both samples (RD –1.1%; 95% CI –2.4 to –0.8%). Estimates for men with secondary levels of education had the greatest RD (–2.4%; 95% CI –3.7 to –1.1%). The sufficiently small RDs between inferred and invited survey samples support the assumption validity and use of our methodology for adjusting for non-participation. However, the presence of some significant differences means caution is required.

Background: Health surveys provide a rich array of information but on relatively small numbers of individuals and evidence suggests that they are becoming less representative as response levels fall. Routinely collected administrative data offer more extensive population coverage but typically comprise fewer health topics. We explore whether data combination and multiple imputation of health variables from survey data is a simple and robust way of generating these variables in the general population. Methods: We use the UK Integrated Household Survey and the English 2011 population census both of which included self-rated general health. Setting aside the census self-rated health data we multiply imputed self-rated health responses for the census using the survey data and compared these with the actual census results in 576 unique groups defined by age, sex, housing tenure and geographic region. Results: Compared with original census data across the groups, multiply imputed proportions of bad or very bad self-rated health were not a markedly better fit than those simply derived from the survey proportions. Conclusion: While multiple imputation may have the potential to augment population data with information from surveys, further testing and refinement is required.

Background: In the context of declining levels of participation, understanding differences between participants and non-participants in health surveys is increasingly important for reliable measurement of health-related behaviors and their social differentials. This study compared participants and non-participants of the Finnish Health 2000 survey, and participants and a representative sample of the target population, in terms of alcohol-related harms (hospitalizations and deaths) and all-cause mortality. Methods: We individually linked 6,127 survey participants and 1,040 non-participants, aged 30–79, and a register-based population sample (n = 496,079) to 12 years of subsequent administrative hospital discharge and mortality data. We estimated age-standardized rates and rate ratios for each outcome for non-participants and the population sample relative to participants with and without sampling weights by sex and educational attainment. Results: Harms and mortality were higher in non-participants, relative to participants for both men (rate ratios = 1.5 [95% confidence interval = 1.2, 1.9] for harms; 1.6 [1.3, 2.0] for mortality) and women (2.7 [1.6, 4.4] harms; 1.7 [1.4, 2.0] mortality). Non-participation bias in harms estimates in women increased with education and in all-cause mortality overall. Age-adjusted comparisons between the population sample and sampling weighted participants were inconclusive for differences by sex; however, there were some large differences by educational attainment level. Conclusions: Rates of harms and mortality in non-participants exceed those in participants. Weighted participants’ rates reflected those in the population well by age and sex, but insufficiently by educational attainment. Despite relatively high participation levels (85%), social differentiating factors and levels of harm and mortality were underestimated in the participants.

Background: Smoking contributes significantly to socioeconomic health inequalities. Vaping has captured much interest as a less harmful alternative to smoking, but may be harmful relative to non-smoking. Examining inequalities in vaping by smoking status, may offer insights into potential impacts of vaping on socioeconomic inequalities in health. Methods: Data were from 3291 youth (aged 10–15) and 35,367 adults (aged 16+) from wave 7 (2015–17) of the UK Household Longitudinal Study. In order to adjust for biases that could be introduced by stratifying on smoking status, marginal structural models were used to estimate controlled direct effects of an index of socioeconomic disadvantage (incorporating household education, occupation and income) on vaping by smoking status (among adults and youth), adjusting for relevant confounders and for selection into smoking states. We also estimated controlled direct effects of socioeconomic disadvantage on being an ex-smoker by vaping status (among adult ever-smokers; n = 18,128). Results: Socioeconomic disadvantage was associated with vaping among never smoking youth (OR for a unit increase in the socioeconomic index: 1.17; 95%: 1.03–1.34), and among ex-smoking adults (OR: 1.17; 95% CI: 1.09–1.26), with little to no association among never smoking (OR: 0.98; 95% CI: 0.91–1.07) and current smoking (OR: 1.00; 95% CI: 0.93–1.07) adults. Socioeconomic disadvantage was also associated with reduced odds of being an ex-smoker among adult ever-smokers, but this association was moderately weaker among those who vaped (OR: 0.88; 95% CI: 0.82–0.95) than those who did not (OR: 0.82; 95% CI: 0.80–0.84; p-value for difference = 0.081). Conclusions: Inequalities in vaping among never smoking youth and adult ex-smokers, suggest potential to widen health inequalities, while weaker inequalities in smoking cessation among adult vapers indicate e-cigarettes could help narrow inequalities. Further research is needed to understand the balance of these opposing potential impacts, and how any benefits can be maximised whilst protecting the vulnerable.

Background: This study examines primary schoolchildren’s perceptions of e-cigarettes and tobacco cigarettes, and associations with parental smoking, vaping and socioeconomic status. Methods: Survey of 2218 10–11-year-old children in 73 schools in Wales. Results: Overall, 36% reported that a parent figure smoked compared to 21% for vaping, with parental smoking lower in affluent families (OR = 0.72; 95% CI = 0.68 to 0.76). Overall, 1% had tried a cigarette, while 5% had tried an e-cigarette. Most said they would not smoke or vape in 2 years’ time; susceptibility to vaping (20%) was higher than smoking (12%). Exposure to and perceptions of tobacco cigarettes were more positive for children of smokers. Having a parent who vaped was associated with exposure to and positive perceptions of e-cigarettes, but not smoking. Most children perceived e-cigarettes as used by adults to stop smoking (64%). Susceptibility to smoking (OR = 0.57; 95% CI = 0.41 to 0.79) and vaping (OR = 0.78; 95% CI = 0.62 to 0.99) were lower among children who perceived e-cigarettes as cessation aids. Conclusions: Parental smoking continues to be concentrated in poorer families. This study provides no evidence that parental vaping in the absence of smoking is associated with more positive perceptions of tobacco cigarettes. Communicating to children the role of e-cigarettes as cessation devices for smokers may help to limit their appeal to young people.

Background: Young people’s experimentation with e-cigarettes has increased in recent years, although regular use remains rare. In May 2016, the EU Tobacco Products Directive (TPD) introduced regulations aimed in part at preventing use by young people. It imposed warnings on e-cigarette packets, banned many forms of advertising, and restricted nicotine strength. This paper examines change in young people’s e-cigarette use after TPD, as well as complementary and alternative causal explanations for change, from young people’s perspectives. Methods: Quantitative data sources were 2013, 2015 and 2017 School Health Research Network/Health Behaviour in School-aged Children surveys in Wales and 2014 and 2016 Smoking Drinking and Drug Use surveys in England. Data were analysed using segmented binary logistic regression in Wales, with simpler before and after analyses in England. Results were considered alongside qualitative interview data from young people aged 14-15 years in England, Wales and Scotland, collected in 2017 and 2018. Results: Ever-use of e-cigarettes almost doubled from 2013-15, though subsequent increases were smaller. In Wales, where pre-legislation time series data were available, under a range of assumptions, prior growth in e-cigarette ever-use did not continue post-TPD. Change in trend post-TPD did not reach significance (OR = 0.96; 95%CI=0.91 to 1.01), but became significant after adjusting for change in smoking rates across the time-series (OR = 0.93; 95%CI=0.88 to 0.98). Regular use did not increase significantly from 2015 to 2017 in Wales, although ever and regular use in England both increased from 2014 to 2016. Young people described limited interactions with core components of TPD, while commonly describing e-cigarette use as a fad which was beginning to run its course. Conclusions: Growth in youth experimentation with e-cigarettes may be slowing. Qualitative data from young people provide a range of explanations which appear largely unrelated to TPD itself. Key messages: Survey data provide preliminary evidence that use of e-cigarettes may be plateauing among young people in the UK after a rapid initial increase in experimentation. Explanations position e-cigarettes as a passing fad which is beginning to lose its appeal in UK youth. Longer term monitoring of trends and perceptions remain vital.

Background: As a consequence of declining levels of participation in health surveys, the results purported to be population-representative may be biased. Traditional adjustments for non-participation, such as weighting, can fail to correct for such biases. We aim to validate our developed methodology, which simulates non-participants, and compare results from the inferred sample to the ’gold standard’ sample of participants and true non-participants, and participants alone. Methods: Participants and non-participants of the Finnish Health 2000 survey, and a contemporaneous population sample are available, with alcohol-related hospitalisations and deaths (“harms”, individually record-linked for all Health 2000 invitees). Synthetic observations on non-participants were simulated through comparison of participants and population sample. Alcohol consumption of true and inferred non-participants were multiply imputed based on harms and education as well as age and sex, assuming data are Missing At Random (MAR). Results are compared via the relative differences (RD) between the inferred sample and 1) gold standard sample, and 2) participants alone. Results: Average weekly estimates for men are 129g in the inferred sample, and 130g in the gold standard (RD -1.2%, 95%CI -2.0, -0.4%), and 35g for women in both samples (RD -0.8%; -1.9, 0.3%). Estimates for men with secondary levels of education had the greatest RD (-1.9%; -3.3, -0.5%). Comparisons between the participants and the inferred sample revealed few differences. Conclusions: All RD between the inferred and gold standard samples lie within our ±5% acceptability limits, in support of the use of our methodology for adjusting for non-participation in health surveys. However, under MAR, there are no significant differences between the results generated from the inferred sample and the participants alone. Further work exploring Missing Not At Random scenarios is required to ensure utility for reliable population health monitoring. Key messages: Survey weights alone cannot adjust for non-representativeness, but we have shown that data linkage can be used to match the characteristics and outcomes of the selected sample. Non-participation in health surveys may be adjusted for using our methodology, with further exploration into alternative missing data scenarios required.

Surveys are key means of obtaining policy-relevant information not available from routine sources. Bias arising from non-participation is typically handled by applying weights derived from limited socio-demographic characteristics. This approach neither captures nor adjusts for differences in health and related behaviours between participants and non-participants within categories. We addressed non-participation bias in alcohol consumption estimates using novel methodology applied to 2003 Scottish Health Survey responses record-linked to prospective administrative data. Differences were identified in socio-demographic characteristics, alcohol-related harm (hospitalisation or mortality) and all-cause mortality between survey participants and, from unlinked administrative sources, the contemporaneous general population of Scotland. These were used to infer the number of non-participants within each subgroup defined by socio-demographics and health outcomes. Synthetic observations for non-participants were then generated, missing only alcohol consumption. Weekly alcohol consumption values among synthetic non-participants were multiply imputed under missing at random and missing not at random assumptions. Relative to estimates adjusted using previously derived weights, the obtained mean weekly alcohol intake estimates were up to 59% higher among men and 16% higher among women, depending on the assumptions imposed. This work demonstrates the universal value of multiple imputation-based methodological advancement incorporating administrative health data over routine weighting procedures.