Research paper
Smoking status, nicotine dependence and happiness in nine countries of the former Soviet Union Andrew Stickley,1,2,3 Ai Koyanagi,4,5 Bayard Roberts,1 Mall Leinsalu,2,6 Yevgeniy Goryakin,7 Martin McKee1 ▸ Additional material is published online only. To view please visit the journal online (http://dx.doi.org/10.1136/ tobaccocontrol-2014-052092). 1
European Centre on Health of Societies in Transition, London School of Hygiene and Tropical Medicine, London, UK 2 Stockholm Centre on Health of Societies in Transition (SCOHOST), Södertörn University, Huddinge, Sweden 3 Department of Human Ecology, Graduate School of Medicine, University of Tokyo, Tokyo, Japan 4 Research and Development Unit, Parc Sanitari Sant Joan de Déu, Fundació Sant Joan de Déu, Sant Boi de Llobregat, Barcelona, Spain 5 Instituto de Salud Carlos III, Centro de Investigación Biomédica en Red de Salud Mental, Cibersam, Spain 6 Department of Epidemiology and Biostatistics, National Institute for Health Development, Tallinn, Estonia 7 Health Economics Group, Norwich Medical School, University of East Anglia, Norwich, UK Correspondence to Dr Andrew Stickley, Stockholm Centre on Health of Societies in Transition, (SCOHOST), Södertörn University, Huddinge 141 89, Sweden; [email protected] Received 9 October 2014 Accepted 16 December 2014 Published Online First 6 January 2015
To cite: Stickley A, Koyanagi A, Roberts B, et al. Tob Control 2015;24:190–197. 190
ABSTRACT Background The US Food and Drug Administration has established a policy of substantially discounting the health benefits of reduced smoking in its evaluation of proposed regulations because of the cost to smokers of the supposed lost pleasure they suffer by no longer smoking. This study used data from nine countries of the former Soviet Union (fSU) to explore this association in a setting characterised by high rates of (male) smoking and smoking-related mortality. Methods Data came from a cross-sectional populationbased study undertaken in 2010/2011 in Armenia, Azerbaijan, Belarus, Georgia, Kazakhstan, Kyrgyzstan, Moldova, Russia and Ukraine. Information was collected from 18 000 respondents aged ≥18 on smoking status (never, ex-smoking and current smoking), cessation attempts and nicotine dependence. The association between these variables and self-reported happiness was examined using ordered probit regression analysis. Results In a pooled country analysis, never smokers and ex-smokers were both significantly happier than current smokers. Smokers with higher levels of nicotine dependence were significantly less happy than those with a low level of dependence. Conclusions This study contradicts the idea that smoking is associated with greater happiness. Moreover, of relevance for policy in the fSU countries, given the lack of public knowledge about the detrimental effects of smoking on health but widespread desire to quit reported in recent research, the finding that smoking is associated with lower levels of happiness should be incorporated in future public health efforts to help encourage smokers to quit by highlighting that smoking cessation may result in better physical and emotional health.
INTRODUCTION Since the seminal research of the 1950s and the subsequent reports of the Royal College of Physicians in the UK in 1962 and Surgeon General in the USA in 1964 stating that smoking causes lung cancer,1 the effects of smoking on physical health have been documented extensively. Smoking has been linked to cardiovascular, metabolic and respiratory diseases, various types of cancer and adverse perinatal outcomes2 with tobacco use having been estimated to have caused approximately 100 million deaths in the 20th century.3 There is, however, a question of how smoking affects psychological well-being. This has recently acquired much greater importance since the US Food and Drug Administration began to introduce the concept of ‘consumer surplus’ into its economic
evaluations of tobacco control measures.4 In essence, this argues that, as smokers are willing to pay more than the actual price for cigarettes, as utility maximising individuals, this implies that they place a value on the assumed pleasure that they obtain from smoking. This argument is supported by reference to observations that show nicotine increases positive mood in healthy as well as in psychiatrically ill individuals,5 and that smokers frequently cite ‘enjoyment’ as a motive for smoking.6 Yet while the theoretical underpinning of the rational choice theory on which the argument of consumer surplus is based has been severely challenged, given factors such as the addictive nature of nicotine,7 the decision by the Food and Drug Administration to invoke it, while providing little empirical justification for doing so, does raise the key question of whether smoking is, indeed, associated with improved mood, especially as discounting the health benefits of reduced smoking may have potentially important consequences for reducing smoking and its effects. In practice, much of the existing research on tobacco use and psychological health has explored its detrimental effects, with studies showing that smoking may precede depression and anxiety disorder or vice versa.8–10 The relationship between tobacco use and negative affect has been described as complex,11 with the pharmacological effect of nicotine in cigarettes possibly having a central role in this association. Specifically, imbibed nicotine binds to nicotine cholinergic receptors in the brain and can affect neurotransmitter activation.12 Through the effects of dopamine, this can produce feelings of pleasure, and alleviate stress and anxiety,12 which possibly helps explain why stress relief is often cited as one of the main reasons for smoking.6 However, neuroadaptation, receptor desensitisation and subsequent dependence in the presence of ongoing nicotine exposure mean that its absence as a result of smoking cessation can also result in withdrawal symptoms such as depressed mood and anxiety,12 especially among those with higher levels of usage. A complementary body of research has examined regret for starting smoking, evaluating responses to the question “If you had to do it over again, you would not have started smoking?” This has found that about 90% of smokers in high-income countries express regret, with the highest levels among women, older smokers, smokers who have made multiple quit attempts, individuals with higher levels of perceived addiction and those worried about subsequent damage to their health.13 High levels are also seen in middle-income countries, but these are
Stickley A, et al. Tob Control 2015;24:190–197. doi:10.1136/tobaccocontrol-2014-052092
Research paper influenced by the overall social acceptability of smoking, itself a function of tobacco control policies, in the country concerned.14 There have been comparatively few studies on how smoking impacts on aspects of positive affect such as happiness.15 As positive and negative affect are not simply end points on a continuum but, rather, as Shahab and West15 have highlighted, distinct dimensions, it is possible that they may have potentially variable relations to smoking. Moreover, tobacco industry documents show that the idea of happiness has been used in the promotion and marketing of cigarettes,16 while cigarette companies when designing brands to appeal to consumers with specific psychological and psychosocial needs found that unhappiness was linked to a greater value being attached to the ‘salience of the delivery level’.17 The limited research undertaken to date on smoking and happiness has produced conflicting results. While one study at the regional level has revealed that higher levels of smoking are linked to lower levels of happiness,18 research on different study populations in various locations has produced more variable findings. Studies have shown that smoking is associated with increased happiness,19 or that there is no relationship20 or that ex-smokers are happier than current smokers21 but that this relationship is conditional on the time since quitting.15 22 Further, in terms of tobacco intake or its pharmacological effect, although some research has indicated that the number of cigarettes consumed among smokers is not related to happiness,21 other studies have indicated that an increase in daily smoking frequency is linked to reduced happiness.23 Smokers who attempt to quit have also been found to be unhappier than those who have never attempted to quit.21 However, the situation is complicated by the observation that heavy smokers demonstrate optimism bias and, compared to non-smokers, markedly underestimate the impact of smoking on mortality.24 25 The current study examined the association between smoking and happiness in nine countries in the former Soviet Union (fSU). This is a particularly apposite site to examine this relationship. Life satisfaction and happiness ratings are especially low in Eastern Europe and fSU countries such as Russia,26 27 while tobacco has a large impact on the disease burden in Eastern Europe,28 with smoking-related mortality being especially high in the fSU countries.29 Although there is evidence that the prevalence of smoking has stabilised in the countries in this region in recent years, it nevertheless remains very high among men,30 and understanding of the effects of tobacco use on health is still limited among the general public,31 as manifest, possibly, in low quit ratios.32 On the other hand, there is a high desire to stop smoking among individuals in these countries.32 In such circumstances, determining how smoking affects mood (happiness) may provide a motivating factor for cessation.15 Against this backdrop, the specific aims of the current study were to: (1) determine the association between smoking status and happiness; (2) examine the association between attempting to quit smoking and happiness; and (3) explore whether nicotine dependence is linked to happiness.
METHODS Study participants The data used in this study came from the Health in Times of Transition (HITT) survey. This cross-sectional survey was undertaken in nine countries: Armenia, Azerbaijan, Belarus, Georgia, Kazakhstan, Moldova, Russia and Ukraine in 2010, and in Kyrgyzstan in early 2011 (due to political violence). Multistage
random sampling was employed in each country to obtain household samples that were nationally representative. Random route procedures were used to select households from within primary sampling units (approximately 100–200 per country). One person aged 18 or above was randomly chosen to participate (determined by the nearest birthday) from within each household. Face-to-face interviews were conducted in the respondents’ homes by trained interviewers using a standard questionnaire. All respondents had the choice of answering in either their country’s language or Russian except for in Russia and Belarus, where Russian was used. Information was collected from 18 000 respondents in total. The sample size was 1800 respondents in six of the nine countries. Russia (n=3000) and Ukraine (n=2000) had larger sample sizes to reflect their larger and more regionally diverse populations. Georgia also had a larger sample size (n=2200). This was the result of a booster survey of 400 additional interviews that was undertaken in late 2010 to ensure that the sample was more representative. Response rates varied from 47% in Kazakhstan to 83% in Georgia. More details of the survey can be obtained from the survey’s website (http://www.hitt-cis.net).
Measures To assess happiness, respondents were asked “Taking all things together, how would you say things are these days—would you say you are?” and then presented with a single-item 10-point scale that ranged from ‘very unhappy’ (scored 1) to ‘very happy’ (scored 10). This single-item measure has been widely employed in subjective well-being research and has been found to be valid and reliable.33 Smoking status was determined using two questions: ‘Do you smoke at least one cigarette per day (1 papirossi, 1 pipe, cigar etc)?’ (with those who answered yes being categorised as current smokers), and ‘Have you ever smoked?’ with answer options ‘Yes, I smoked but stopped’ (ex-smokers) and ‘No, I don’t smoke and I have never smoked’ (never smokers). Attempting to stop smoking (cessation attempts) was assessed by asking smokers, ‘How many times have you tried to give up smoking?’ with response options ‘never’, ‘once’, ‘twice’ and ‘more than twice’. Nicotine dependence was assessed using the Fagerström Test for Nicotine Dependence,34 which is comprised of 6 questions, the answers to which when summed form a score ranging from 0–10 with cut points of 0–2 (very low), 3–4 (low), 5 (medium), 6–7 (high) and 8–10 (very high).35 Eight factors were controlled for in the analyses as various demographic and socioeconomic factors have been reported to be linked to happiness across countries26 and may also affect smoking. Age in years was divided into five categories: 18–29, 30–39, 40–49, 50–59 and 60 and above. Three marital status categories were created: married/cohabiting, never married and divorced/widowed. Educational attainment was also divided into three categories: high (complete/incomplete higher education), middle (complete secondary/secondary special education) and low (incomplete secondary education or lower). Wealth was assessed using a household asset index that consisted of 10 items (fridge, TV, computer, etc). Principal component analysis was used to generate wealth tertiles (high, average and low). Self-rated health was categorised as either very good/good/fair or poor/very poor. The residential location of respondents was classified as either urban or rural. In addition, as recent research has suggested that alcohol consumption is related to lower happiness in these countries,36 and that heavy drinking and smoking are associated in this region,37 we also controlled for heavy episodic drinking. Following the definition employed in
Stickley A, et al. Tob Control 2015;24:190–197. doi:10.1136/tobaccocontrol-2014-052092
191
Research paper several recent studies in these countries, this was defined as consumption of at least one of the following on one occasion: ≥2 L of beer, ≥750 g of wine, or ≥200 g of strong spirits.38 39
Statistical analysis The prevalence of the smoking status categories and mean (SD) happiness scores by baseline characteristics were calculated (table 1). Next, multivariable ordered probit regression analysis was used to examine the relationship between the different smoking status categories and happiness in each individual country, and in a pooled analysis of all countries while controlling for age, sex, marital status, education, wealth, self-rated health, location, heavy episodic drinking and individual country effects (table 2). Multivariable ordered probit regression analysis was also used to test the association between happiness and (1) smoking cessation attempts; (2) nicotine dependence among current smokers (table 3). These models were also adjusted for age, sex, marital status, education, wealth, self-rated health, location and heavy episodic drinking. For this analysis, as the restriction only to those who currently smoke resulted in a small sample size in some countries, countries’ data were combined in order to increase the statistical power. Pooled country analyses were all adjusted for country. All regression analyses were performed using ordered probit regression analysis, which is theoretically more efficient than ordinary least squares (OLS) for analysing ordered outcomes40 and has been extensively used in happiness research. The β-coefficients and SEs are reported in the tables. In order to facilitate understanding of these estimates, we also report the results (OR and 95% CIs) obtained from ordinal logistic regression analyses, which are presented in an online appendix (see online supplementary tables A1 and A2). The statistical analysis was carried out with Stata V.12.1 (Stata Corp LP, College Station, Texas, USA). The level of statistical significance was set at p
Smoking status, nicotine dependence and happiness in nine countries of the former Soviet Union Andrew Stickley,1,2,3 Ai Koyanagi,4,5 Bayard Roberts,1 Mall Leinsalu,2,6 Yevgeniy Goryakin,7 Martin McKee1 ▸ Additional material is published online only. To view please visit the journal online (http://dx.doi.org/10.1136/ tobaccocontrol-2014-052092). 1
European Centre on Health of Societies in Transition, London School of Hygiene and Tropical Medicine, London, UK 2 Stockholm Centre on Health of Societies in Transition (SCOHOST), Södertörn University, Huddinge, Sweden 3 Department of Human Ecology, Graduate School of Medicine, University of Tokyo, Tokyo, Japan 4 Research and Development Unit, Parc Sanitari Sant Joan de Déu, Fundació Sant Joan de Déu, Sant Boi de Llobregat, Barcelona, Spain 5 Instituto de Salud Carlos III, Centro de Investigación Biomédica en Red de Salud Mental, Cibersam, Spain 6 Department of Epidemiology and Biostatistics, National Institute for Health Development, Tallinn, Estonia 7 Health Economics Group, Norwich Medical School, University of East Anglia, Norwich, UK Correspondence to Dr Andrew Stickley, Stockholm Centre on Health of Societies in Transition, (SCOHOST), Södertörn University, Huddinge 141 89, Sweden; [email protected] Received 9 October 2014 Accepted 16 December 2014 Published Online First 6 January 2015
To cite: Stickley A, Koyanagi A, Roberts B, et al. Tob Control 2015;24:190–197. 190
ABSTRACT Background The US Food and Drug Administration has established a policy of substantially discounting the health benefits of reduced smoking in its evaluation of proposed regulations because of the cost to smokers of the supposed lost pleasure they suffer by no longer smoking. This study used data from nine countries of the former Soviet Union (fSU) to explore this association in a setting characterised by high rates of (male) smoking and smoking-related mortality. Methods Data came from a cross-sectional populationbased study undertaken in 2010/2011 in Armenia, Azerbaijan, Belarus, Georgia, Kazakhstan, Kyrgyzstan, Moldova, Russia and Ukraine. Information was collected from 18 000 respondents aged ≥18 on smoking status (never, ex-smoking and current smoking), cessation attempts and nicotine dependence. The association between these variables and self-reported happiness was examined using ordered probit regression analysis. Results In a pooled country analysis, never smokers and ex-smokers were both significantly happier than current smokers. Smokers with higher levels of nicotine dependence were significantly less happy than those with a low level of dependence. Conclusions This study contradicts the idea that smoking is associated with greater happiness. Moreover, of relevance for policy in the fSU countries, given the lack of public knowledge about the detrimental effects of smoking on health but widespread desire to quit reported in recent research, the finding that smoking is associated with lower levels of happiness should be incorporated in future public health efforts to help encourage smokers to quit by highlighting that smoking cessation may result in better physical and emotional health.
INTRODUCTION Since the seminal research of the 1950s and the subsequent reports of the Royal College of Physicians in the UK in 1962 and Surgeon General in the USA in 1964 stating that smoking causes lung cancer,1 the effects of smoking on physical health have been documented extensively. Smoking has been linked to cardiovascular, metabolic and respiratory diseases, various types of cancer and adverse perinatal outcomes2 with tobacco use having been estimated to have caused approximately 100 million deaths in the 20th century.3 There is, however, a question of how smoking affects psychological well-being. This has recently acquired much greater importance since the US Food and Drug Administration began to introduce the concept of ‘consumer surplus’ into its economic
evaluations of tobacco control measures.4 In essence, this argues that, as smokers are willing to pay more than the actual price for cigarettes, as utility maximising individuals, this implies that they place a value on the assumed pleasure that they obtain from smoking. This argument is supported by reference to observations that show nicotine increases positive mood in healthy as well as in psychiatrically ill individuals,5 and that smokers frequently cite ‘enjoyment’ as a motive for smoking.6 Yet while the theoretical underpinning of the rational choice theory on which the argument of consumer surplus is based has been severely challenged, given factors such as the addictive nature of nicotine,7 the decision by the Food and Drug Administration to invoke it, while providing little empirical justification for doing so, does raise the key question of whether smoking is, indeed, associated with improved mood, especially as discounting the health benefits of reduced smoking may have potentially important consequences for reducing smoking and its effects. In practice, much of the existing research on tobacco use and psychological health has explored its detrimental effects, with studies showing that smoking may precede depression and anxiety disorder or vice versa.8–10 The relationship between tobacco use and negative affect has been described as complex,11 with the pharmacological effect of nicotine in cigarettes possibly having a central role in this association. Specifically, imbibed nicotine binds to nicotine cholinergic receptors in the brain and can affect neurotransmitter activation.12 Through the effects of dopamine, this can produce feelings of pleasure, and alleviate stress and anxiety,12 which possibly helps explain why stress relief is often cited as one of the main reasons for smoking.6 However, neuroadaptation, receptor desensitisation and subsequent dependence in the presence of ongoing nicotine exposure mean that its absence as a result of smoking cessation can also result in withdrawal symptoms such as depressed mood and anxiety,12 especially among those with higher levels of usage. A complementary body of research has examined regret for starting smoking, evaluating responses to the question “If you had to do it over again, you would not have started smoking?” This has found that about 90% of smokers in high-income countries express regret, with the highest levels among women, older smokers, smokers who have made multiple quit attempts, individuals with higher levels of perceived addiction and those worried about subsequent damage to their health.13 High levels are also seen in middle-income countries, but these are
Stickley A, et al. Tob Control 2015;24:190–197. doi:10.1136/tobaccocontrol-2014-052092
Research paper influenced by the overall social acceptability of smoking, itself a function of tobacco control policies, in the country concerned.14 There have been comparatively few studies on how smoking impacts on aspects of positive affect such as happiness.15 As positive and negative affect are not simply end points on a continuum but, rather, as Shahab and West15 have highlighted, distinct dimensions, it is possible that they may have potentially variable relations to smoking. Moreover, tobacco industry documents show that the idea of happiness has been used in the promotion and marketing of cigarettes,16 while cigarette companies when designing brands to appeal to consumers with specific psychological and psychosocial needs found that unhappiness was linked to a greater value being attached to the ‘salience of the delivery level’.17 The limited research undertaken to date on smoking and happiness has produced conflicting results. While one study at the regional level has revealed that higher levels of smoking are linked to lower levels of happiness,18 research on different study populations in various locations has produced more variable findings. Studies have shown that smoking is associated with increased happiness,19 or that there is no relationship20 or that ex-smokers are happier than current smokers21 but that this relationship is conditional on the time since quitting.15 22 Further, in terms of tobacco intake or its pharmacological effect, although some research has indicated that the number of cigarettes consumed among smokers is not related to happiness,21 other studies have indicated that an increase in daily smoking frequency is linked to reduced happiness.23 Smokers who attempt to quit have also been found to be unhappier than those who have never attempted to quit.21 However, the situation is complicated by the observation that heavy smokers demonstrate optimism bias and, compared to non-smokers, markedly underestimate the impact of smoking on mortality.24 25 The current study examined the association between smoking and happiness in nine countries in the former Soviet Union (fSU). This is a particularly apposite site to examine this relationship. Life satisfaction and happiness ratings are especially low in Eastern Europe and fSU countries such as Russia,26 27 while tobacco has a large impact on the disease burden in Eastern Europe,28 with smoking-related mortality being especially high in the fSU countries.29 Although there is evidence that the prevalence of smoking has stabilised in the countries in this region in recent years, it nevertheless remains very high among men,30 and understanding of the effects of tobacco use on health is still limited among the general public,31 as manifest, possibly, in low quit ratios.32 On the other hand, there is a high desire to stop smoking among individuals in these countries.32 In such circumstances, determining how smoking affects mood (happiness) may provide a motivating factor for cessation.15 Against this backdrop, the specific aims of the current study were to: (1) determine the association between smoking status and happiness; (2) examine the association between attempting to quit smoking and happiness; and (3) explore whether nicotine dependence is linked to happiness.
METHODS Study participants The data used in this study came from the Health in Times of Transition (HITT) survey. This cross-sectional survey was undertaken in nine countries: Armenia, Azerbaijan, Belarus, Georgia, Kazakhstan, Moldova, Russia and Ukraine in 2010, and in Kyrgyzstan in early 2011 (due to political violence). Multistage
random sampling was employed in each country to obtain household samples that were nationally representative. Random route procedures were used to select households from within primary sampling units (approximately 100–200 per country). One person aged 18 or above was randomly chosen to participate (determined by the nearest birthday) from within each household. Face-to-face interviews were conducted in the respondents’ homes by trained interviewers using a standard questionnaire. All respondents had the choice of answering in either their country’s language or Russian except for in Russia and Belarus, where Russian was used. Information was collected from 18 000 respondents in total. The sample size was 1800 respondents in six of the nine countries. Russia (n=3000) and Ukraine (n=2000) had larger sample sizes to reflect their larger and more regionally diverse populations. Georgia also had a larger sample size (n=2200). This was the result of a booster survey of 400 additional interviews that was undertaken in late 2010 to ensure that the sample was more representative. Response rates varied from 47% in Kazakhstan to 83% in Georgia. More details of the survey can be obtained from the survey’s website (http://www.hitt-cis.net).
Measures To assess happiness, respondents were asked “Taking all things together, how would you say things are these days—would you say you are?” and then presented with a single-item 10-point scale that ranged from ‘very unhappy’ (scored 1) to ‘very happy’ (scored 10). This single-item measure has been widely employed in subjective well-being research and has been found to be valid and reliable.33 Smoking status was determined using two questions: ‘Do you smoke at least one cigarette per day (1 papirossi, 1 pipe, cigar etc)?’ (with those who answered yes being categorised as current smokers), and ‘Have you ever smoked?’ with answer options ‘Yes, I smoked but stopped’ (ex-smokers) and ‘No, I don’t smoke and I have never smoked’ (never smokers). Attempting to stop smoking (cessation attempts) was assessed by asking smokers, ‘How many times have you tried to give up smoking?’ with response options ‘never’, ‘once’, ‘twice’ and ‘more than twice’. Nicotine dependence was assessed using the Fagerström Test for Nicotine Dependence,34 which is comprised of 6 questions, the answers to which when summed form a score ranging from 0–10 with cut points of 0–2 (very low), 3–4 (low), 5 (medium), 6–7 (high) and 8–10 (very high).35 Eight factors were controlled for in the analyses as various demographic and socioeconomic factors have been reported to be linked to happiness across countries26 and may also affect smoking. Age in years was divided into five categories: 18–29, 30–39, 40–49, 50–59 and 60 and above. Three marital status categories were created: married/cohabiting, never married and divorced/widowed. Educational attainment was also divided into three categories: high (complete/incomplete higher education), middle (complete secondary/secondary special education) and low (incomplete secondary education or lower). Wealth was assessed using a household asset index that consisted of 10 items (fridge, TV, computer, etc). Principal component analysis was used to generate wealth tertiles (high, average and low). Self-rated health was categorised as either very good/good/fair or poor/very poor. The residential location of respondents was classified as either urban or rural. In addition, as recent research has suggested that alcohol consumption is related to lower happiness in these countries,36 and that heavy drinking and smoking are associated in this region,37 we also controlled for heavy episodic drinking. Following the definition employed in
Stickley A, et al. Tob Control 2015;24:190–197. doi:10.1136/tobaccocontrol-2014-052092
191
Research paper several recent studies in these countries, this was defined as consumption of at least one of the following on one occasion: ≥2 L of beer, ≥750 g of wine, or ≥200 g of strong spirits.38 39
Statistical analysis The prevalence of the smoking status categories and mean (SD) happiness scores by baseline characteristics were calculated (table 1). Next, multivariable ordered probit regression analysis was used to examine the relationship between the different smoking status categories and happiness in each individual country, and in a pooled analysis of all countries while controlling for age, sex, marital status, education, wealth, self-rated health, location, heavy episodic drinking and individual country effects (table 2). Multivariable ordered probit regression analysis was also used to test the association between happiness and (1) smoking cessation attempts; (2) nicotine dependence among current smokers (table 3). These models were also adjusted for age, sex, marital status, education, wealth, self-rated health, location and heavy episodic drinking. For this analysis, as the restriction only to those who currently smoke resulted in a small sample size in some countries, countries’ data were combined in order to increase the statistical power. Pooled country analyses were all adjusted for country. All regression analyses were performed using ordered probit regression analysis, which is theoretically more efficient than ordinary least squares (OLS) for analysing ordered outcomes40 and has been extensively used in happiness research. The β-coefficients and SEs are reported in the tables. In order to facilitate understanding of these estimates, we also report the results (OR and 95% CIs) obtained from ordinal logistic regression analyses, which are presented in an online appendix (see online supplementary tables A1 and A2). The statistical analysis was carried out with Stata V.12.1 (Stata Corp LP, College Station, Texas, USA). The level of statistical significance was set at p
