There is wide variation in the Cessation Ratios among the 28 EU MS sampled, with the highest Cessation Ratios found in Northern Europe. On an individual level, having some financial difficulty, a proxy measure for SES status, was associated with a less successful quit attempt, which echoes the existing evidence base [3, 12, 14, 16, 22, 23]. We did not find significant associations between other sociodemographic factors including age and gender and the likelihood of a successful quit attempt. On a country level, we found a quadratic relationship between smoking prevalence and odds of a successful quit attempt. There were no significant associations between odds of success and a country’s GDP per capita, unemployment rates, prevalence of e-cigarettes or TCS treatment score.
In our analysis some Northern European countries had higher Cessation Ratios compared to Southern European countries, although during our modelling no significant association between odds of success and European region of residence was demonstrated. Previous literature have suggested that Southern Europeans are less likely to use smoking cessation aids when attempting to quit [27], which has been associated with lower likelihood of success, but this association is inconsistent [28, 29]. Southern European countries may also have less comprehensive community healthcare and primary care framework to support smoking cessation activities, which can affect motivation, efficacy and likelihood of success [30].
We found a quadratic relationship between smoking prevalence and the Cessation Ratio, with a transition point at a prevalence of around 26.3%. The relationship was U-shaped indicating that the odds of quitting were optimal when smoking prevalence is either very low or very high. Although socioeconomic and cultural differences between European countries pose major challenges in formulating an overarching explanation of this finding, it might reflect a true phenomenon. In communities where smoking prevalence is high, there may be a large number of smokers who are able to quit relatively easily, when effective tobacco control measures such as smoking bans or tax increases are implemented. With higher smoking prevalence, the proportion of ‘easy quitters’ might be lower, hence smokers find it, on average, more difficult to quit. This could explain the upper end of the association and provide some support to the so-called ‘Hardening Hypothesis’ [31], although there has been a growing body of evidence against this where ‘hardening’ has not been demonstrated [32, 33].
However, on the other end of the U-shape relationship, the odds of success is higher where prevalence is lower. It is possible that as with lower prevalence of tobacco smoking, smoking becomes denormalised and less socially appropriate, which might motivate smokers to quit and make them more effective in their quit attempts. This is echoed in existing literature [32, 33]. There is also literature suggesting ‘softening’ of the smoking population as opposed to ‘hardening’ – with lower overall smoking prevalence, there could be a higher prevalence of ‘light smokers’ and a lower prevalence of ‘hardcore smokers’, and as a result the overall population-level likelihood of successful cessation increases [34, 35]. Lower smoking prevalence also implies that there are more former smokers, who can provide support and serve as role models. This is supported by a study by Giovino et al. showing that self-efficacy for quitting, intention to quit and successful abstinence at 3 months or more are all higher where prevalence is lower [36]. Self-efficacy itself is a predictor of successful cessation [7, 15], which could explain the trend we found.
We found a significant association between having financial difficulties, a proxy for socioeconomic status, and the odds of a successful quit attempt, which is in line with current evidence [3, 12, 14, 16, 22, 23]. It possibly reflects the fact that having financial difficulties is likely a confluence of conditions that influence successful cessation, rather than an independent factor. Existing tobacco control policies have been found to be most effective in higher SES groups [9], and having access to healthcare and therefore medical advice and cessation assistance through insurance, is also associated with higher likelihood of successful cessation [5]. In addition, lower odds of success have been demonstrated in high levels of nicotine dependence [7, 37], poorer mental health [38, 39] and living in a home that permitted smoking [5], all of which are conditions that are more likely amongst smokers in lower SES groups [40]. These factors would be an important area for future research assessing associations with successful cessation, but had not been included in our study as they were beyond the scope of our data set.
Aside from socioeconomic status, we found no significant associations between other sociodemographic factors and odds of successful cessation. Earlier analyses have found similar results [15, 16, 41]. Although in one study males were found to be more likely to make a quit attempt [10], they were not more likely to be successful in it.
Previous studies have shown that a higher TCS treatment score, or having policies to increase access to cessation aids, was associated with higher rates of smoking cessation [42–44]. In contrast, we did not find any association between TCS treatment score and having been successful in a recent quit attempt. However, our analysis was restricted to those who had made an attempt. Treatment provisions could influence both a smoker’s decision to make a quit attempt and their chances of success through complex mechanisms; our study was not able to disentangle such associations but further research in this area would be beneficial to clarify the mechanisms through which availability of cessation support affects cessation efforts and success. For instance, there has been a significant increase in the use of e-cigarettes by the public as a smoking cessation aid [45], but their effectiveness is still unclear and therefore have not been included in most national treatment efforts [16–18, 46]. Our analysis echoes previous studies and did not find any significant positive associations between the prevalence of e-cigarettes and the likelihood of successful cessation [16, 18].
4.1 Strengths and Limitations
The Eurobarometer survey is representative of the EU population 15 years and older, and the sampling methodology has been standardised across 28 EU MS, allowing valid comparisons and generalisation of results across EU populations. Although there can be discrepancies between the Eurobarometer and national surveys due to differences in phrasing, sampling methods and sample sizes, existing literature finds a positive and significant correlation between Eurobarometer and national survey data [47]. Our study also looks at attempts to quit within approximately the last 12 months, providing a more focused time frame and allows interpretation alongside any concurrent tobacco control policies. It improves upon the more commonly used quit ratio, which is a cumulative measure including all former smokers, regardless of when they achieved abstinence.
However, the selection of current and former smokers who were included in the analysis was based on different questions suggesting a slightly different time frame for recent successful or unsuccessful quit attempts. As a result, the Cessation Ratio we estimated should not be interpreted as an actual ratio of successful over unsuccessful quitters, which was impossible to estimate with the available data. Nevertheless, the standardised methodology of Eurobarometer across Member States allowed us to make country-level comparisons using this ratio as a proxy indicator of smoking cessation success. The sample of current and former smokers with recent quit attempts was small across the countries, which introduces uncertainty in some of the estimates. Additionally, although there is high agreement between self-reported cigarette use and biochemical testing [48, 49], self-reporting is less accurate for smoking cessation [50, 51], especially considering that Eurobarometer questions did not define a time frame for smoking abstinence.