Does misclassification of former tobacco smokers explain the 'smoker's paradox' in the risk of COVID-19? Insights from the Stockholm Public Health Cohort.

BACKGROUND: The association between tobacco smoking and the risk of COVID-19 and its adverse outcomes is controversial, as studies reported contrasting findings. Bias due to misclassification of the exposure in the analyses of current versus non-current smoking could be a possible explanation because former smokers may have higher background risks of the disease due to co-morbidity. The aim of the study was to investigate the extent of this potential bias by separating non-, former, and current smokers when assessing the risk or prognosis of diseases. METHODS: We analysed data from 43,400 participants in the Stockholm Public Health Cohort, Sweden, with information on smoking obtained prior to the pandemic. We estimated the risk of COVID-19, hospital admissions and death for (a) former and current smokers relative to non-smokers, (b) current smokers relative to non-current smokers, that is, including former smokers; adjusting for potential confounders (aRR). RESULTS: The aRR of a COVID-19 diagnosis was elevated for former smokers compared with non-smokers (1.07; 95% confidence interval (CI) =1.00-1.15); including hospital admission with any COVID-19 diagnosis (aRR= 1.23; 95% CI = 1.03-1.48); or with COVID-19 as the main diagnosis (aRR=1.23, 95% CI= 1.01-1.49); and death within 30 days with COVID-19 as the main or a contributory cause (aRR=1.40; 95% CI=1.00-1.95). Current smoking was negatively associated with risk of COVID-19 (aRR=0.79; 95% CI=0.68-0.91). CONCLUSIONS: Separating non-smokers from former smokers when assessing the disease risk or prognosis is essential to avoid bias. However, the negative association between current smoking and the risk of COVID-19 could not be entirely explained by misclassification.

Health behaviours as a predictor of quitting hazardous alcohol use in the Stockholm Public Health Cohort.

Background: Adopting healthy behaviours may facilitate the transition from hazardous to non-hazardous use of alcohol, yet, longitudinal studies of health behaviours in relation to the cessation of hazardous alcohol use are rare. We addressed this question using data from a large population-based cohort of adults in Sweden (Stockholm Public Health Cohort). Methods: Participants from two sub-cohorts (inception in 2002 and 2010), with follow-up until the year 2014 were included. Health behaviours (tobacco use, diet and physical activity) and alcohol use were self-reported in questionnaire-based surveys. Hazardous alcohol use was defined as either usual weekly consumption (2002 sub-cohort) or heavy occasional alcohol consumption (2010 sub-cohort). Baseline hazardous drinkers with complete data constituted the analytical sample (n = 8946). Logistic regression was used to calculate the Odds Ratios and their 95% confidence intervals of quitting hazardous alcohol use, with tobacco use, diet and physical activity as predictors of change. Results: In the 2002 sub-cohort, 28% reported non-hazardous use sustained through two consecutive follow-up points. In the 2010 sub-cohort, 36% of the participants reported non-hazardous use of alcohol at follow-up. Favourable health behaviours at baseline (e.g. no tobacco use, sufficient fruit intake and physical activity) were associated with a 19% to 75% higher of odds quitting hazardous alcohol use. Further, favourable changes in diet and tobacco cessation were associated with non-hazardous alcohol use at follow-up. Conclusions: As many as one-third of hazardous alcohol users may quit this drinking pattern in a medium-long term. Holding or achieving a healthy lifestyle may facilitate this transition.

Association between adolescents' academic aspirations and expectations and mental health: a one-year follow-up study.

Background: Mental health problems among youth have increased in Sweden in recent decades, as has competition in higher education and the labour market. It is unknown whether the increasing emphasis put on educational achievement might negatively affect adolescents' mental health. We aimed to investigate the relationship between adolescents' academic aspirations and expectations and the risk of mental health problems. Methods: We studied 3343 Swedish 7th grade adolescents (age 13), who participated in the first two waves of the KUPOL longitudinal study; participants answered a questionnaire encompassing the five-item Future Aspirations and Goals (FG) subscale of the Student Engagement Instrument, two questions about their own academic aspirations and expectations and two mental health instruments: the Center for Epidemiological studies for Children (CES-DC) (α=.90) and the Strengths and Difficulties Questionnaire (SDQ) (α=.78). The association between aspirations and expectations at baseline and mental health at follow-up was analysed using logistic regression models adjusting for baseline mental health, socio-demographic and family factors. Results: The FG subscale was inversely and linearly associated with the odds of high CES-DC score [adjusted OR (odds ratio) 0.71, 95% CI (confidence interval): 0.59-0.86], total Strengths and Difficulties Questionnaire score (OR 0.59, 95% CI 0.49-0.71), and its internalizing (OR 0.70, 95% CI 0.59-0.84) and externalizing problems scores (OR 0.58, 95% CI 0.48-0.71). Conclusions: Adolescents with high individual academic aspirations have less mental health problems at 1-year follow-up. Future studies should investigate whether interventions aimed at increasing aspirations and engagement in school may prevent mental health problems in adolescence.

Are changes in occupational physical activity level compensated by changes in exercise behavior?

Background: Physically active occupations with high-energy expenditure may lead to lower motivation to exercise during leisure time, while the reverse can be hypothesized for sedentary occupations. The aim of this study was to investigate the impact of changing occupational activity level on exercise behavior. Methods: Data on occupational physical activity and leisure time exercise were taken from a population-based cohort, with surveys completed in 2010 and 2014. Using data on those employed in both years, two trajectories were analyzed: (i) participants who changed from sedentary to active occupations and (ii) participants who changed from active to sedentary occupations. Exercise was reported in hours per week and changes from 2010 to 2014 were categorized as decreased, increased or stable. Associations were expressed as ORs and 95% CIs adjusting for age, gender and education. Results: Data were available for 12 969 participants (57% women, aged 45 ± 9 years, 57% highly educated). Relative to participants whose occupational activity was stable, participants who changed to active occupations (n = 549) were more likely to decrease exercise (OR = 1.22, 95% CI = 1.02-1.47) and those who changed to sedentary occupations (n = 373) more likely to increase exercise levels (OR = 1.21, 95% CI = 0.97-1.52). Conclusion: People changing from sedentary to active occupations compensate by exercising less, and those changing from physically active to sedentary occupations seem to compensate by exercising more in their leisure time. When developing and evaluating interventions to reduce occupational sedentary behavior or to promote exercise, mutual influences on physical activity of different contexts should be considered.

Do unfavourable alcohol, smoking, nutrition and physical activity predict sustained leisure time sedentary behaviour? A population-based cohort study.

Comparing lifestyle of people remaining sedentary during longer periods of their life with those favourably changing their behaviour can provide cues to optimize interventions targeting sedentary behaviour. The objective of this study was to determine lifestyle predictors of sustained leisure time sedentary behaviour and assess whether these predictors were dependent on gender, age, socioeconomic position and occupational sedentary behaviour. Data from a large longitudinal population-based cohort of adults (aged 18-97years) in Stockholm responding to public health surveys in 2010 and 2014 were analysed (n=49,133). Leisure time sedentary behaviour was defined as >3h per day of leisure sitting time e.g. watching TV, reading or using tablet. Individuals classified as sedentary at baseline (n=9562) were subsequently categorized as remaining sedentary (n=6357) or reduced sedentary behaviour (n=3205) at follow-up. Lifestyle predictors were unfavourable alcohol consumption, smoking, nutrition, and physical activity. Odds ratios (OR) and corresponding 95% Confidence Intervals (CI) were calculated, adjusting for potential confounders. Unfavourable alcohol consumption (OR=1.22, CI:1.11-1.34), unfavourable candy- or cake consumption (OR=1.15, CI:1.05-1.25), and unfavourable physical activity in different contexts were found to predict sustained sedentary behaviour, with negligible differences according to gender, age, socioeconomic position and occupational sedentary behaviour. People with unfavourable lifestyle profiles regarding alcohol, sweets, or physical activity are more likely to remain sedentary compared to sedentary persons with healthier lifestyle. The impact of combining interventions to reduce leisure time sedentary behaviour with reducing alcohol drinking, sweet consumption and increasing physical activity should be tested as a promising strategy for behavioural modification.

Evaluation of a brief counseling for tobacco cessation in dental clinics among Swedish smokers and snus users. A cluster randomized controlled trial (the FRITT study).

OBJECTIVE: The aim of this study is to assess the effectiveness of a very brief structured counseling for tobacco cessation in dentistry clinics. METHOD: A cluster randomized trial was conducted in Sweden in 2012-2013. Twenty-seven dentistry clinics in two Swedish counties were randomized to provide either a structured brief advice based on the 5 A's model or usual care. Participants were 467 patients currently using tobacco daily (225 in the intervention group and 242 in usual care), of which 97% were retained at follow-up, six months after enrolment. Study outcomes were: 7-day abstinence (primary outcome); 3-month sustained abstinence; 50% reduction of the amount tobacco used; quit attempts lasting at least 24h. RESULTS: Compared to usual care, brief counseling was not associated to statistically significant increase in the proportion abstinent from tobacco use after 6months. However, there was a statistically significant association with reduction of tobacco consumption (OR=2.07 95% CI 1.28-3.35). Changes in the expected direction for all outcomes were more frequent in the intervention than in the usual care group, and larger among exclusive snus users than among smokers. CONCLUSIONS: Very brief and structured counseling in dentistry may achieve positive behavioral modifications among tobacco users, with significant reduction of tobacco consumption, particularly among smokeless tobacco users.

Electronic cigarette use and smoking cessation in cohort studies and randomized trials: A systematic review and meta-analysis.

INTRODUCTION: The aim of this systematic review and meta-analysis was to assess the association between e-cigarette use and subsequent smoking cessation in cohort studies and randomized controlled trials (RCT). METHODS: A systematic literature search was finalized 11 November 2019 using EMBASE, Cochrane Library, Scopus, PubMed Health, NICE evidence search, PROSPERO, CRD, PsycInfo, and PubMed including Medline. Inclusion criteria were: reporting empirical results; longitudinal observational design with a minimum of 3 months of follow-up; including general population samples; and allowing for comparison between users and non-users of e-cigarettes. Studies rated as having high risk of bias were excluded. The procedures described by PRISMA were followed, and the quality of evidence was rated using GRADE. RESULTS: Twenty-eight longitudinal, peer-reviewed publications from 26 cohort studies, and eight publications from seven RCTs assessing the association between e-cigarette use and smoking cessation were included in this review. A random-effects meta-analysis based on 39147 participants in cohort studies showed a pooled unadjusted odds ratio (OR) for smoking cessation among baseline e-cigarette users compared with baseline non-users of 0.97 (95% CI: 0.67-1.40), while the adjusted OR was 0.90 (95% CI: 0.63-1.27). The pooled odds ratio for smoking cessation in RCTs was 1.78 (95% CI: 1.41-2.25). The evidence for cohort studies was graded as very low and for RCTs as low. CONCLUSIONS: We did not find quality evidence for an association between e-cigarette use and smoking cessation. Although RCTs tended to support a more positive association between e-cigarette use and smoking cessation than the cohort studies, the grading of evidence was consistently low.

Protocol for the evaluation of cost-effectiveness and health equity impact of a school-based tobacco prevention programme in a cluster randomised controlled trial (the TOPAS study).

INTRODUCTION: Despite a long-term downward trend in smoking prevalence, tobacco remains the number one risk factor for death and disability in Sweden. Globally, tobacco use generates a substantial economic burden for health systems and is also a major driver of socioeconomic inequalities in health. This article describes the planned cost-effectiveness and health equity impact evaluation of a multicomponent school-based programme to prevent the onset of tobacco use in adolescents. METHODS AND ANALYSIS: Cost-effectiveness of the multicomponent Tobacco-Free Duo programme will be evaluated against the educational component of the same programme only. An incremental cost-effectiveness ratio (ICER) will be calculated in terms of the cost per case prevented using the trial primary outcome and within-trial payer costs. If the ICER is negative, an incremental net benefit ratio will be calculated. Robustness of the results will be assessed through one-way sensitivity analyses. The slope index of inequality will be computed to assess the potential impact of the Tobacco-free Duo programme on education-related inequalities in the onset of smoking and in adult smoking cessation, comparing the two trial arms. ETHICS AND DISSEMINATION: Ethical approval was obtained from the Regional Ethics Review Board, Umeå (registration number 2017/255-31). The Public Health Agency of Sweden commissioned the study. The findings will be disseminated internationally within academia and to national and local policy-makers. TRIAL REGISTRATION NUMBER: ISRCTN52858080; Pre-results.

Unfavourable sedentary and physical activity behaviour before and after retirement: a population-based cohort study.

BACKGROUND: During transition to retirement there is often a rearrangement of daily life which might provide a key opportunity for interventions to promote a non-sedentary and active lifestyle. To be able to design effective interventions, it is essential to know which sedentary and physical behaviour domains (eg, at home or during leisure time) have potential to facilitate healthy ageing during the retirement transition. OBJECTIVE: To determine whether unfavourable sedentary and physical activity behaviour before retirement predict unfavourable sedentary and physical activity behaviour after retirement. DESIGN: Population-based cohort. SETTING AND PARTICIPANTS: Adults (n=3272) employed in 2010 but retired in 2014. METHODS: Self-reported preretirement job activity, sedentary leisure time, physical activity at home, and walking-cycling and exercise were assessed as predictors for unfavourable sedentary and physical activity behaviours after retirement using logistic regression. Unfavourable behaviours were defined based on the respective median of the cohort distribution. Furthermore, the OR for having multiple unfavourable behaviours after retirement was determined, based on the amount of unfavourable behaviours before retirement. All models were adjusted for gender and education. RESULTS: Unfavourable preretirement physical activity and sedentary behaviour at home or during leisure time were the strongest predictors of the same behaviours after retirement. Unfavourable job activity did not predict physical activity but did predict unfavourable sedentary behaviour after retirement (OR=1.66, 95% CI 1.41 to 1.96). Unfavourable exercise behaviour before retirement predicted unfavourable sedentary and physical activity after retirement in all domains. With all behaviours being unfavourable before retirement, the OR of having at least three unfavourable behaviours after retirement was 36.7 (95% CI 16.8 to 80.5). CONCLUSIONS: Adults with a higher number of unfavourable preretirement physical activity and sedentary behaviours are likely to carry these unfavourable behaviours into retirement age. Interventions should target those with more unfavourable preretirement physical activity and sedentary behaviours before retirement, and those interventions focusing on exercise might have greatest potential.

Effect of tobacco control policies on the Swedish smoking quitline using intervention time-series analysis.

OBJECTIVES: To coherently examine the responsiveness of the Swedish National Tobacco Quitline (SNTQ) to different types of anti-smoking policies over an extended period of calendar time. DESIGN: Quasi-experimental design with an intervention time-series analysis based on 19 years series of data collected between January 1999 and August 2017 (224 months). Statistical inference on calling rates and rate ratios was obtained using intervention time-series models (Poisson regression and transfer functions). PARTICIPANTS: A total of 179 851 phone calls to the SNTQ. INTERVENTIONS: Recent application of the 2014/40/ European Union (EU) Tobacco Products Directive in 2016. Historical interventions such as a campaign on passive smoking in January 2001; introduction of larger text warnings on cigarette packages since September 2002; banning smoking in restaurants since June 2005; and tobacco tax increase by 10% since January 2012. OUTCOME MEASURE: Calling rates to the SNTQ expressed per 100 000 smokers. SETTING: Sweden. RESULTS: The introduction of large pictorial warnings together with text warnings on cigarette packages (May 2016) was associated with a 35% increase in SNTQ calling rate (95% CI 1.16 to 1.57). The campaign on passive smoking (Jan 2001) was associated with a 61% higher calling rate (95% CI 1.06 to 2.45). Larger text warnings on cigarette packs (Sept 2002) conferred a 28% increment in the calling rate (95% CI 1.15 to 1.42); and prohibition to smoke in restaurants (Jun 2005) was associated with a 15% increase in the calling rate (95% CI 1.01 to 1.30). The 10% tobacco tax increase (Jan 2012) was associated with a 3% higher calling rate (95% CI 0.90 to 1.19). CONCLUSIONS: Within an overall decreasing trend of daily smoking in Sweden, we found that the recent introduction of pictorial warnings together with text warnings and referral text had a discernible positive impact on the calling rates to the smoking quitline. We were also able to detect a likely impact of earlier nationwide interventions.

Maternal smoking during pregnancy: a comparison between concurrent and retrospective self-reports.

Retrospective reports of smoking in pregnancy are of importance for clinical or scientific purposes. Careful analyses of stability and accuracy of recalled behaviour are, therefore, needed. In 1998, the mothers of 2369 pre-teens born in Sweden retrospectively reported their smoking behaviour during the first trimester of the index pregnancy. We matched these reports with those recorded by midwives at the beginning of the index pregnancy, using information from the Swedish Medical Birth Registry. Using this registry as gold standard, the sensitivity and specificity of the retrospective reports containing any smoking were 83.9% and 92.8% respectively, but the sensitivity was low for daily smoking, 56.0%. Of the 222 discordant reports, 19.0% were due to mothers recalling daily smoking which was not reported at the time of pregnancy, and 42% were due to failure to recall smoking reported at the time of pregnancy, while the remaining 39% retrospectively reported occasional smoking, whereas they were registered as non-daily smokers when pregnant. Retrospective recall of pregnancy smoking is fairly stable over time.

Economic evaluation of a brief counselling for smoking cessation in dentistry: a case study comparing two health economic models.

OBJECTIVES: This study aimed to compare the cost-effectiveness estimates of a brief counselling of smoking cessation in dentistry by using two different health economic models. DESIGN AND OUTCOME MEASURES: Intervention effectiveness was estimated in a cluster randomised controlled trial. The number of quitters was estimated based on 7-day abstinence and on smoking reduction at follow-up. Health economic evaluation was performed using two models: (1) a population-based model employing potential impact fractions and (2) a Markov model estimating the cost-effectiveness of the intervention for the actual participants. The evaluation was performed from healthcare and societal perspectives, and health gains were expressed in quality-adjusted life-years (QALYs). SETTING: Dental clinics in Sweden. PARTICIPANTS: 205 Swedish smokers aged 20-75 years. INTERVENTIONS: A brief, structured behavioural intervention was compared with 'usual care'. RESULTS: The cost per quitter was US$552 in the intervention and US$522 in the 'usual care' condition. The net saving estimated with the population-based model was US$17.3 million for intervention and US$49.9 million for 'usual care', with health gains of 1428 QALYs and 2369 QALYs, respectively, for the whole Swedish population during 10 years. The intervention was thus dominated by 'usual care'. The reverse was true when using the Markov model, showing net societal savings of US$71 000 for the intervention and US$57000 for 'usual care', with gains of 5.42 QALYs and 4.74 QALYs, respectively, for lifelong quitters. CONCLUSION: The comparison of intervention and 'usual care' derived from small-scale studies may be highly sensitive to the choice of the model used to calculate cost-effectiveness. TRIAL REGISTRATION: The cluster randomised trial is registered in the ISRCTN register of controlled trials with identification number ISRCTN50627997.

Beyond intention-to-treat: The effect of brief counseling for tobacco cessation in secondary analyses of a cluster randomized controlled trial in Swedish dental clinics.

In experimental studies the assigned intervention measures the received intervention if full protocol adherence is achieved, but this is rarely the case in public health. The objective of this study was to estimate the effect of a brief counseling intervention delivered in Swedish dental clinics on tobacco use cessation, taking non-adherence into account. We conducted three secondary analyses. In a per-protocol analysis the experimental counseling delivered as intended was contrasted to usual care (control). In an as-treated analysis individuals were compared according to the counseling components actually received, disregarding randomization. In an instrumental variable analysis the effect of the intervention among those who would always be treated as assigned was estimated. Logistic regression was used to examine the association between tobacco cessation outcomes (seven-day abstinence, three-month abstinence, half-reduction, quit attempts) and the defined exposure to the intervention. Protocol adherence in the intervention group was 73.4%. The per-protocol analysis closely replicated the results of the intention-to-treat analysis, showing a statistically significant effect of the brief counseling on the reduction in tobacco consumption OR = 1.81, 95% CI [1.06, 3.07], but no significant effect for other outcomes. In the as-treated analysis, receiving more counseling components compared with no tobacco counseling increased the likelihood of half-reduction. The instrumental variable yielded biased results. We conclude that despite application problems, conducting per-protocol, as-treated and instrumental variable analyses in randomized trials where experimental conditions are not strictly standardized strengthens and puts in context the inference based on intention-to-treat analysis.