Mortality in relation to smoking history: 13 years' follow-up of 68,000 Norwegian men and women 35-49 years

Impact of global smoking prevalence on mortality: a study across income groups

BACKGROUND

Smoking significantly contributes to the mortality rates worldwide, particularly in non-communicable and preventable diseases such as cardiovascular ailments, respiratory conditions, stroke, and lung cancer. This study aims to analyse the impact of smoking on global deaths, and its association with mortality across the main income groups.

METHODS

The comprehensive analysis spans 199 countries and territories from 1990 to 2019. The study categorises countries into four income groups: high income, upper middle income, lower middle income, and low income.

RESULTS

The findings underscore the profound impact of global tobacco smoking on mortality. Notably, cardiovascular disease mortality is notably affected in both upper-middle-income and high-income groups. Chronic respiratory disease mortality rates show a significant impact across all income groups. Moreover, stroke-related mortality is observed in the lower-middle, upper-middle, and high-income groups. These results highlight the pervasive influence of smoking prevalence on global mortality, affecting individuals across various socioeconomic levels.

CONCLUSION

The study underscores the critical implications of smoking on mortality rates, particularly in high-income countries. It emphasises the urgency of targeted interventions in these regions to address the specific challenges posed by tobacco smoking on public health. Policy recommendations include implementing prohibitive measures extending to indoor public areas such as workplaces and public transportation services. Furthermore, allocating funds for research on tobacco and health, is imperative to ensure policymakers are consistently informed about emerging facts and trends in this complex domain.

Smoking history and all-cause, ischaemic heart disease and lung cancer mortality: follow-up study of 358 551 men and women aged 40-43 years

AIMS

We studied the health consequences of quitting smoking before age 43 by time since quitting, number of years smoked and cigarettes smoked per day. The outcomes were all-cause, ischaemic heart disease and lung cancer mortality.

DESIGN

Prospective study.

SETTING

Norwegian counties.

PARTICIPANTS

Men and women aged 40-43 years who participated in a national cardiovascular screening programme and who were followed from 1985 to 2018.

MEASUREMENTS

Self-reports from questionnaire on time since quitting smoking, years smoked and number of cigarettes per day, and measurements of height, weight and blood pressure, and a blood sample where serum was analysed for total serum cholesterol and triglycerides.

FINDINGS

The all-cause mortality rate was 30% higher among quitters less than 1 year ago compared with never smokers (adjusted HR=1.30, 95% CI 1.18-1.43 in men and HR=1.31, 95% CI 1.16 to 1.50 in women). Quitters who had smoked longer than 20 years had 23% higher mortality in men (HR=1.23, 95% CI 1.14 to 1.34) and 32% higher mortality in women (HR=1.32, 95% CI 1.18 to 1.49). Past smoking of more than 20 cigarettes/day was associated with HR=1.14 (1.05-1.23) in men and HR=1.16 (1.01-1.32) in women. The HR for lung cancer was 6.77 (95% CI 4.86 to 9.45) for quitting men who had smoked for more than 20 years compared with never smokers. The corresponding figure for women was 5.75 (95% CI 4.08 to 8.09).

CONCLUSIONS

The mortality among quitters was close to that of never smokers, except for a higher mortality for lung cancer, which on the other hand was much lower than the lung cancer mortality in current smokers.

Proposal for the Inclusion of Tobacco Use in Suicide Risk Scales: Results of a Meta-Analysis

There is an association between smoking and suicide, even though the direction and nature of this relationship remains controversial. This meta-analysis aimed to evaluate the association between smoking and suicidal behaviours (ideation, planning, suicide attempts, and death by suicide). On 24 August 2020, we searched the PubMed, Cochrane library, Scopus, Web of Science, TRIP, and SCIENCE DIRECT databases for relevant articles on this topic. Twenty prospective cohort studies involving 2,457,864 participants were included in this meta-analysis. Compared with never smokers, former and current smokers had an increased risk of death by suicide (relative risk [RR] = 1.31; 95% CI [1.13, 1.52] and RR = 2.41; 95% CI [2.08, 2.80], respectively), ideation (RR = 1.35; 95% CI [1.31, 1.39] and RR = 1.84; 95% CI [1.21, 2.78]), and attempted suicide (RR = 1.27; 95% CI [0.56, 2.87] and RR = 1.71; 95% CI [0.73, 3.97]). Moreover, compared to never smokers, current smoker women (RR = 2.51; 95% CI [2.06–3.04] had an increased risk of taking their own life (Q = 13,591.53; p < 0.001) than current smoker men (RR = 2.06; 95% CI [1.62–2.62]. Furthermore, smoking exposure (former and current smokers) was associated with a 1.74-fold increased risk (95% CI [1.54, 1.96]) of suicidal behaviour (death by suicide, ideation, planning, or attempts). Thus, because of the prospective relationship between smoking and suicidal behaviours, smoking should be included in suicide risk scales as a useful and easy item to evaluate suicide risk.

Gender Differences in Residual Risk Factors for Major Adverse Cardiovascular Events Following ACS and How to Bridge the Gap

PURPOSE OF REVIEW

The review aims to describe the differences between men and women in those factors that can influence a worse prognosis in women after an acute cardiovascular event.

RECENT FINDINGS

Women adequately treated with current evidence-based medications for acute myocardial infarction and for conventional cardiovascular risk factors, such as hypertension, diabetes, smoking, and dyslipidemia, still have an extra risk of death compared with men. Additional factors that increase the risk of poor prognosis for the index event have been identified. The residual risk can be due to factors affecting the prognosis of the women from outside (they are external to the patient's body) and also to factors that, on the contrary, belong to the female body (female being/female sex). The review will give an update on those residual risk factors, including young age, vulnerability for de novo heart failure, time from symptom onset to treatment, heath care delivered during the weekend, and depression, which generally negatively influence the outcome of women with an acute myocardial infarction.

Association of smoking with incident CKD risk in the general population: A community-based cohort study

BACKGROUND

Chronic kidney disease (CKD) is a public health problem, and an unfavorable lifestyle has been suggested as a modifiable risk factor for CKD. Cigarette smoking is closely associated with cardiovascular disease and cancers; however, there is a lack of evidence to prove that smoking is harmful for kidney health. Therefore, we aimed to determine the relationship between cigarette smoking and CKD among healthy middle-aged adults.

METHODS

Using the database from the Korean Genome and Epidemiology Study, we analyzed 8,661 participants after excluding those with baseline estimated glomerular filtration rate (eGFR)<60 ml/min/1.72 m2 or proteinuria. Exposure of interest was smoking status: never-, former-, and current-smokers. Primary outcome was incident CKD defined as eGFR <60 ml/min/1.73 m2 or newly developed proteinuria.

RESULTS

The mean age of the subjects was 52 years, and 47.6% of them were males. There were 551 (6.4%) and 1,255 (14.5%) subjects with diabetes and hypertension, respectively. The mean eGFR was 93.0 ml/min/1.73 m2. Among the participants, 5,140 (59.3%), 1,336 (15.4%), and 2,185 (25.2%) were never-smokers, former-smokers, and current-smokers, respectively. During a median follow-up of 11.6 years, incident CKD developed in 1,941 (22.4%) subjects with a crude incidence rate of 25.1 (24.0-26.2) per 1,000 person-years. The multivariable Cox regression analysis after adjustment of confounding factors showed hazard ratios (95% confidence interval) of 1.13 (0.95-1.35) and 1.26 (1.07-1.48) for CKD development in the former- and current-smokers, compared with never-smokers.

CONCLUSION

This study showed that smoking was associated with a higher risk of incident CKD among healthy middle-aged adults.

Predictors of tobacco smoking among acutely ill patients in a Moscow hospital: A cross-sectional study

INTRODUCTION

Tobacco smoking is a major preventable risk factor for non-communicable diseases. The aim of this study was to investigate predictors of tobacco smoking among acute medically ill patients admitted to a Moscow hospital, and the association between smoking and alcohol use.

METHODS

Patients admitted to the V. P. Demikhov hospital in Moscow from November 2016 through December 2017 were asked to participate in this study (inclusion criteria were acute medically ill patients aged ≥18 years). Sociodemographic data were collected, in addition to questionnaires on mental distress (Hopkins Symptom Checklist 5), alcohol use (Alcohol Use Disorder Identification Test 4, AUDIT-4) and smoking (Fagerström Test for Nicotine Dependence).

RESULTS

A total of 3009 patients were recruited to the study. Using a binary logistic regression model adjusted for all variables, it was found that living without a partner resulted in a higher risk of smoking tobacco compared to being married or living with a partner (odds ratio, OR=1.60 for divorced, p=0.001; and OR=1.62 for single, p=0.002), and being economically non-active resulted in a higher risk compared to being economically active (OR=1.47; p=0.003). Harmful alcohol use (AUDIT-4 score ≥5 [for females] / 7 [for males]) resulted in a higher risk of smoking compared to those without harmful alcohol use (OR=4.04; p<0.001).

CONCLUSIONS

Smoking was highly prevalent and associated with other adverse sociodemographic and lifestyle factors such as harmful alcohol use.

Effects of cigarette smoking on blood lipids in Korean men: Cardiovascular and Metabolic Diseases Etiology Research Center cohort

BACKGROUND/AIMS

Cigarette smoking and abnormal blood lipids are major risk factors for cardiovascular disease. The results of previous studies on the relationship between cigarette smoking and dyslipidemia are controversial. In the present study, we investigated the independent association between cigarette smoking and blood lipid levels in a male Korean population.

METHODS

A total of 1,932 men aged from 30 to 64 years old participated in the Cardiovascular and Metabolic Diseases Etiology Research Center cohort study. Smoking history was obtained by in-person interviews. In all regression models, measurements of triglyceride levels were log-transformed.

RESULTS

Triglyceride levels were higher in current smokers than in never-smokers (median: 149 mg/dL vs. 115 mg/dL, p < 0.001) even after adjusting age, body mass index, alcohol intake, systolic blood pressure, fasting glucose, physical activity, and nutrition intake (β = 0.14, p < 0.001). We further divided people into heavy and light smokers using 20 pack-years as the cut-off. Higher triglyceride were found in current heavy smokers (β = 0.18, p < 0.001), current light smokers (β = 0.13, p < 0.001), as well as in past heavy smokers (β = 0.08, p = 0.037), as compared to never-smokers. Moreover, significantly lower high-density lipoprotein cholesterol (HDL-C) were observed in current heavy smokers (β = -2.27 mg/dL, p = 0.009).

CONCLUSION

Cigarette smoking is associated with higher triglyceride in Korean men, with the most dramatic effect seen in current smokers with a smoking history of more than 20 pack-years. HDL-C were also lower in current smokers with more than 20 pack-years.

Differential Impact of Cigarette Smoking on Prognosis in Women and Men Undergoing Percutaneous Coronary Intervention

We sought to compare the effects of smoking on clinical outcomes in women and men with coronary artery disease undergoing percutaneous coronary intervention (PCI). We prospectively followed up 10 369 patients undergoing elective PCI. All patients were stratified according to smoking status and sex. The impacts of smoking on long-term major adverse cardiovascular events (MACEs, the composite of all-cause death, myocardial infarction, or target vessel revascularization) were assessed. Among 7773 men and 2596 women undergoing PCI, the prevalence of cigarette smoking was 66.7% (n = 5185) and 11.0% (n = 286; P < .001). During the 3 years of follow-up (median: 20.6 months), smoking increased MACE in both men and women (men 10.8% vs 8.1%, P < .001; women 23.2% vs 6.4%; P < .001). After adjusting for baseline characteristics, smoking had a greater effect on MACE in women (hazard ratio [HR]: 3.68, 95% confidence interval [CI]: 1.86-7.28; P < .001) compared with men (HR: 1.35, 95% CI: 1.03-1.77; P = .005, interaction P = .026). There was a lower prevalence of smoking in women compared to men among patients undergoing PCI. However, smoking confers a higher excess risk for MACE among women compared with men.

Dose-risk relationships between cigarette smoking and ovarian cancer histotypes: a comprehensive meta-analysis

PURPOSE

Although smoking has not been associated with overall ovarian cancer risk, a different impact on various histotypes has been reported. Our aim is to provide an accurate, up-to-date estimate of the dose-risk relationships between cigarette smoking and epithelial ovarian cancer, overall and by histotypes.

METHODS

Using an innovative approach for the identification of original study publications, we conducted a systematic review and meta-analysis of epidemiological studies published on the topic until September 2018. Summary relative risks (RR) for cigarette smoking were estimated using random-effects models; dose-risk relationships were evaluated using one-stage random-effects models with restricted cubic splines.

RESULTS

Thirty-seven studies were considered in the meta-analysis. The summary RRs for current versus never smokers were 1.05 (95% confidence interval CI 0.95-1.16) for overall ovarian cancer, 1.78 (95% CI 1.52-2.07) for mucinous, 0.77 (95% CI 0.65-0.93) for clear cell, 0.81 (95% CI 0.73-0.91) for endometrioid, and 1.05 (95% CI 0.94; 1.17) for serous cancer. The risk of borderline mucinous (RR 2.09) and serous (RR 1.16) tumors was higher than for invasive cancers (RR 1.44 and 0.95, respectively). For mucinous cancer, risk was noticeably higher with smoking intensity and duration (RR 2.35 for 20 cigarettes/day, and 2.11 for 20 years of smoking). A non-significant linear relation was found with smoking intensity, duration, and time since quitting for overall ovarian cancer and other histotypes.

CONCLUSIONS

This uniquely large and comprehensive meta-analysis confirms that although cigarette smoking does not appear to be a risk factor for ovarian cancer, and it is even slightly protective for some rare histotypes, there is a strong dose-risk relationship with mucinous ovarian cancer.

Smoking status and subsequent gastric cancer risk in men compared with women: a meta-analysis of prospective observational studies

Background

Smoking is one of the well-established risk factors for gastric cancer incidence, yet whether men are more or equally susceptible to gastric cancer due to smoking compared with women is a matter of controversy. The aim of this study was to investigate and compare the effect of sex on gastric cancer risk associated with smoking.

Methods

We conducted a systemic literature search in MEDLINE, EMBASE, and the Cochrane CENTRAL databases to identify studies published from inception to December 2018. We included prospective observational studies which reported effect estimates with 95% confidence intervals (CIs) for associations of current or former smokers with the incidence of gastric cancer by sex. We calculated the ratio of relative risk (RRR) with corresponding 95% CI based on sex-specific effect estimates for current or former smokers versus non-smokers on the risk of gastric cancer.

Results

We included 10 prospective studies with 3,381,345 participants in our analysis. Overall, the summary RRR (male to female) for gastric cancer risk in current smokers was significantly increased compared with non-smokers (RRR: 1.30; 95% CI: 1.05–1.63; P = 0.019). Furthermore, there was no significant sex difference for the association between former smokers and gastric cancer risk (RRR: 1.20; 95% CI: 0.92–1.55; P = 0.178). However, the result of sensitivity analysis indicated the pooled result was not stable, which was altered by excluding a nested case-control study (RRR: 1.31; 95% CI: 1.10–1.57; P = 0.002).

Conclusion

This systematic review showed a potential sex difference association between current smokers and the risk of gastric cancer. The sex differential in smokers can give important clues for the etiology of gastric cancers and should be examined in further studies.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5601-9) contains supplementary material, which is available to authorized users.

Is externalizing psychopathology a robust risk factor for suicidal thoughts and behaviors? A meta-analysis of longitudinal studies

OBJECTIVE

Our primary objective was to determine the potency of externalizing psychopathology as a risk factor for suicidal thoughts and behaviors (STBs).

METHOD

We conducted a random effects meta-analysis of 174 prospective studies (839 unique statistical tests) examining externalizing psychopathology and suicidal thoughts and behaviors (STBs) published prior to December 8, 2017. The weighted mean odds ratios for the overall relationship between externalizing psychopathology and STBs were below 2.00 in magnitude, and all risk factor subcategories were also fairly modest predictors of STBs. Taking publication bias into account reduced the magnitude of these associations, particularly for death. Although externalizing psychopathology modestly predicts STBs, this may be due to design limitations of existing studies. Future research should employ shorter follow-up periods, consider risk factors in combination, and focus on forms of externalizing psychopathology that have not been studied extensively.

RESULTS

The weighted mean odds ratios for the overall relationship between externalizing psychopathology and STBs were below 2.00 in magnitude, and all risk factor subcategories were also fairly modest predictors of STBs. Taking publication bias into account reduced the magnitude of these associations, particularly for death. Additionally, our results were mostly consistent regardless of sample age, sample severity, follow-up length, and predictor scale.

CONCLUSIONS

Although externalizing psychopathology modestly predicts STBs, this may be due to design limitations of existing studies. Future research should employ shorter follow-up periods, consider risk factors in combination, and focus on forms of externalizing psychopathology that have not been studied extensively.

Brief exposure to Swedish snus causes divergent vascular responses in healthy male and female volunteers

Introduction

The use of Swedish oral moist snuff, known as snus, has for a long time been limited to the Scandinavian countries. With declining cigarette sales in the western world, tobacco companies have looked to the development of alternative tobacco products. In 2006 snus products were launched in the US. Even though several studies have demonstrated negative health effects, snus is often depicted as harmless.

The aim of the present study was to investigate acute vascular effects of snus as measured by arterial stiffness as well as blood pressure and heart rate.

Methods

Two separate randomized double-blind crossover studies with the same study design were pooled for analysis. Twenty-nine healthy snus-users (17 females, 12 males) were included. Snus (Göteborgs Rapé) and tobacco free snus (Onico) were administered in a randomized order at two separate visits. Arterial stiffness, blood pressure and heart rate were measured at baseline as well as every five minutes for 40 minutes during exposure. Following snus removal, measurements continued for 30 minutes post exposure. Arterial stiffness was measured using pulse wave velocity (Vicorder) and pulse wave analysis (Sphygmocor).

Results

Compared to placebo, snus significantly increased systolic and diastolic blood pressure as well as heart rate, however, only in females (p = 0.004, p = 0.006 and p<0.001 respectively). No changes were seen in arterial stiffness measurements in either gender.

Conclusion

We observed an increase in blood pressure and heart rate only in females, but not in males due to snus usage as compared to placebo. This novel finding was surprising and needs to be further investigated considering most of the earlier studies have mainly focused on male snus users and the increasing usage of snus among females.

Tobacco addiction in the psychiatric population and in the general population

Objective:

To estimate the degree of tobacco addiction and identify independently associated factors by comparing the psychiatric population of secondary and tertiary care with the general population of the primary healthcare network.

Method:

This is a cross-sectional epidemiological study, conducted in a municipality of São Paulo, with 134 smokers of a Mental Health Outpatient Unit (MHOU), a Psychiatric Hospital (PH), and a Primary Healthcare Unit (PHU). Data were collected by means of individual interviews, recorded on a mobile device. Data were statistically processed using Stata/12

Results:

Of the 134 participants, 54.5% were women. While 49.1% of the psychiatric population (MHOU/PH) had medium/high nicotine addiction, 58.3% of smokers of the general population had very low/low dependency. The Poisson regression model indicated a higher prevalence of smokers with high dependence among men (PR = 1.41), people aged 49 years or less (15 - 29 years, PR = 4.06, 30 - 39 PR = 2.96 years, 40 - 49 years PR = 1.84), with severe mental disorders (PR = 3.05), with anxiety disorders/other (PR = 3.98), and with high suicide risk (PR = 1.55).

Conclusion:

Nicotine dependence was greater in the psychiatric population than in the general population. The independent factors associated with severe dependence were sex, age group, diagnosis, and current risk of suicide. These results trigger reflection among nurses on the need to focus more attention on a neglected subject in mental health services.

Prospective association between tobacco smoking and death by suicide: a competing risks hazard analysis in a large twin cohort with 35-year follow-up

BACKGROUND

The relationship between smoking and suicide remains controversial.

METHOD

A total of 16 282 twin pairs born before 1958 in Finland and alive in 1974 were queried with detailed health and smoking questionnaires in 1975 and 1981, with response rates of 89% and 84%. Smoking status and dose, marital, employment, and socio-economic status, and indicators of psychiatric and somatic illness were assessed at both time points. Emergent psychiatric and medical illness and vital status, including suicide determined by forensic autopsy, were evaluated over 35-year follow-up through government registries. The association between smoking and suicide was determined in competing risks hazard models. In twin pairs discordant for smoking and suicide, the prospective association between smoking and suicide was determined using a matched case-control design.

RESULTS

Smokers had a higher cumulative suicide incidence than former or never smokers. Heavy smokers had significantly higher suicide risk [hazard ratio (HR) 3.47, 95% confidence interval (CI) 2.31-5.22] than light smokers (HR 2.30, 95% CI 1.61-3.23) (p = 0.017). Compared with never smokers, smokers, but not former smokers, had increased suicide risk (HR 2.56, 95% CI 1.43-4.59), adjusting for depressive symptoms, alcohol and sedative-hypnotic use, and excluding those who developed serious somatic or psychiatric illness. In twin pairs discordant for smoking and suicide, suicide was more likely in smokers [odds ratio (OR) 6.0, 95% CI 2.06-23.8].

CONCLUSIONS

Adults who smoked tobacco were more likely to die by suicide, with a large, dose-dependent effect. This effect remained after consideration of many known predictors of suicide and shared familial effects, consistent with the hypothesis that exposure to tobacco smoke increases the risk of suicide.

The Role of DNA Methylation in Cardiovascular Risk and Disease: Methodological Aspects, Study Design, and Data Analysis for Epidemiological Studies

Epidemiological studies have demonstrated that genetic, environmental, behavioral, and clinical factors contribute to cardiovascular disease development. How these risk factors interact at the cellular level to cause cardiovascular disease is not well known. Epigenetic epidemiology enables researchers to explore critical links between genomic coding, modifiable exposures, and manifestation of disease phenotype. One epigenetic link, DNA methylation, is potentially an important mechanism underlying these associations. In the past decade, there has been a significant increase in the number of epidemiological studies investigating cardiovascular risk factors and outcomes in relation to DNA methylation, but many gaps remain in our understanding of the underlying cause and biological implications. In this review, we provide a brief overview of the biology and mechanisms of DNA methylation and its role in cardiovascular disease. In addition, we summarize the current evidence base in epigenetic epidemiology studies relevant to cardiovascular health and disease and discuss the limitations, challenges, and future directions of the field. Finally, we provide guidelines for well-designed epigenetic epidemiology studies, with particular focus on methodological aspects, study design, and analytical challenges.

Cardiovascular risk prediction: a comparative study of Framingham and quantum neural network based approach

PURPOSE

Currently cardiovascular diseases (CVDs) are the main cause of death worldwide. Disease risk estimates can be used as prognostic information and support for treating CVDs. The commonly used Framingham risk score (FRS) for CVD prediction is outdated for the modern population, so FRS may not be accurate enough. In this paper, a novel CVD prediction system based on machine learning is proposed.

METHODS

This study has been conducted with the data of 689 patients showing symptoms of CVD. Furthermore, the dataset of 5,209 CVD patients of the famous Framingham study has been used for validation purposes. Each patient's parameters have been analyzed by physicians in order to make a diagnosis. The proposed system uses the quantum neural network for machine learning. This system learns and recognizes the pattern of CVD. The proposed system has been experimentally evaluated and compared with FRS.

RESULTS

During testing, patients' data in combination with the doctors' diagnosis (predictions) are used for evaluation and validation. The proposed system achieved 98.57% accuracy in predicting the CVD risk. The CVD risk predictions by the proposed system, using the dataset of the Framingham study, confirmed the potential risk of death, deaths which actually occurred and had been recorded as due to myocardial infarction and coronary heart disease in the dataset of the Framingham study. The accuracy of the proposed system is significantly higher than FRS and other existing approaches.

CONCLUSION

The proposed system will serve as an excellent tool for a medical practitioner in predicting the risk of CVD. This system will be serving as an aid to medical practitioners for planning better medication and treatment strategies. An early diagnosis may be effectively made by using this system. An overall accuracy of 98.57% has been achieved in predicting the risk level. The accuracy is considerably higher compared to the other existing approaches. Thus, this system must be used instead of the well-known FRS.

Long-term smoking cessation and heart rate dynamics in an aging healthy cohort: Is it possible to fully recover?

AIM

To evaluate the long-term influence of smoking cessation on the regulation of the autonomic cardiovascular system in an aging general population, using the subpopulation of lifelong non-smokers as control group.

METHODS

We analyzed 1481 participants aged ≥50 years from the SAPALDIA cohort. In each participant, heart rate variability and heart rate dynamics were characterized by means of various quantitative analyzes of the inter-beat interval time series generated from 24-hour electrocardiogram recordings. Each parameter obtained was then used as the outcome variable in multivariable linear regression models in order to evaluate the association with smoking status and time elapsed since smoking cessation. The models were adjusted for known confounding factors and stratified by the time elapsed since smoking cessation.

RESULTS

Our findings indicate that smoking triggers adverse changes in the regulation of the cardiovascular system, even at low levels of exposure since current light smokers exhibited significant changes as compared to lifelong non-smokers. Moreover, there was evidence for a dose-response effect. Indeed, the changes observed in current heavy smokers were more marked as compared to current light smokers. Furthermore, full recovery was achieved in former smokers (i.e., normalization to the level of lifelong non-smokers). However, while light smokers fully recovered within the 15 first years of cessation, heavy former smokers might need up to 15-25 years to fully recover.

CONCLUSION

This study supports the substantial benefits of smoking cessation, but also warns of important long-term alterations caused by heavy smoking.

Using the Negative Exponential Model to Describe Changes in Risk of Smoking-Related Diseases following Changes in Exposure to Tobacco

Recently published analyses for four smoking-related diseases show that the declining excess relative risk by time quit is well fitted by the negative exponential model. These analyses estimated the half-life of this excess, that is, the time after quitting when the excess relative risk reaches half that for continuing smokers. We describe extensions of the simple model. One quantifies the decline following an exposure reduction. We show that this extension satisfactorily predicts results from studies investigating the effect of reducing cigarette consumption. It may also be relevant to exposure reductions following product-switching. Another extension predicts changes in excess relative risk occurring following multiple exposure changes over time. Suitable published epidemiological data are unavailable to test this, and we recommend its validity to be investigated using large studies with data recorded on smoking habits at multiple time points in life. The basic formulae described assume that the excess relative risk for a continuing smoker is linearly related to exposure and that the half-life is invariant of age. We describe model adaptations to allow for nonlinear dose-response and for age-dependence of the half-life. The negative exponential model, though relatively simple, appears to have many potential uses in epidemiological research for summarizing variations in risk with exposure changes.

Psychosocial interventions for smoking cessation in patients with coronary heart disease

BACKGROUND

This is an update of a Cochrane review previously published in 2008. Smoking increases the risk of developing atherosclerosis but also acute thrombotic events. Quitting smoking is potentially the most effective secondary prevention measure and improves prognosis after a cardiac event, but more than half of the patients continue to smoke, and improved cessation aids are urgently required.

OBJECTIVES

This review aimed to examine the efficacy of psychosocial interventions for smoking cessation in patients with coronary heart disease in short-term (6 to 12 month follow-up) and long-term (more than 12 months). Moderators of treatment effects (i.e. intervention types, treatment dose, methodological criteria) were used for stratification.

SEARCH METHODS

The Cochrane Central Register of Controlled Trials (Issue 12, 2012), MEDLINE, EMBASE, PsycINFO and PSYNDEX were searched from the start of the database to January 2013. This is an update of the initial search in 2003. Results were supplemented by cross-checking references, and handsearches in selected journals and systematic reviews. No language restrictions were applied.

SELECTION CRITERIA

Randomised controlled trials (RCTs) in patients with CHD with a minimum follow-up of 6 months.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial eligibility and risk of bias. Abstinence rates were computed according to an intention to treat analysis if possible, or if not according to completer analysis results only. Subgroups of specific intervention strategies were analysed separately. The impact of study quality on efficacy was studied in a moderator analysis. Risk ratios (RR) were pooled using the Mantel-Haenszel and random-effects model with 95% confidence intervals (CI).

MAIN RESULTS

We found 40 RCTs meeting inclusion criteria in total (21 trials were new in this update, 5 new trials contributed to long-term results (more than 12 months)). Interventions consist of behavioural therapeutic approaches, telephone support and self-help material and were either focused on smoking cessation alone or addressed several risk factors (eg. obesity, inactivity and smoking). The trials mostly included older male patients with CHD, predominantly myocardial infarction (MI). After an initial selection of studies three trials with implausible large effects of RR > 5 which contributed to substantial heterogeneity were excluded. Overall there was a positive effect of interventions on abstinence after 6 to 12 months (risk ratio (RR) 1.22, 95% confidence interval (CI) 1.13 to 1.32, I² 54%; abstinence rate treatment group = 46%, abstinence rate control group 37.4%), but heterogeneity between trials was substantial. Studies with validated assessment of smoking status at follow-up had similar efficacy (RR 1.22, 95% CI 1.07 to 1.39) to non-validated trials (RR 1.23, 95% CI 1.12 to 1.35). Studies were stratified by intervention strategy and intensity of the intervention. Clustering reduced heterogeneity, although many trials used more than one type of intervention. The RRs for different strategies were similar (behavioural therapies RR 1.23, 95% CI 1.12 to 1.34, I² 40%; telephone support RR 1.21, 95% CI 1.12 to 1.30, I² 44%; self-help RR 1.22, 95% CI 1.12 to 1.33, I² 40%). More intense interventions (any initial contact plus follow-up over one month) showed increased quit rates (RR 1.28, 95% CI 1.17 to 1.40, I² 58%) whereas brief interventions (either one single initial contact lasting less than an hour with no follow-up, one or more contacts in total over an hour with no follow-up or any initial contact plus follow-up of less than one months) did not appear effective (RR 1.01, 95% CI 0.91 to 1.12, I² 0%). Seven trials had long-term follow-up (over 12 months), and did not show any benefits. Adverse side effects were not reported in any trial. These findings are based on studies with rather low risk of selection bias but high risk of detection bias (namely unblinded or non validated assessment of smoking status).

AUTHORS' CONCLUSIONS

Psychosocial smoking cessation interventions are effective in promoting abstinence up to 1 year, provided they are of sufficient duration. After one year, the studies showed favourable effects of smoking cessation intervention, but more studies including cost-effectiveness analyses are needed. Further studies should also analyse the additional benefit of a psychosocial intervention strategy to pharmacological therapy (e.g. nicotine replacement therapy) compared with pharmacological treatment alone and investigate economic outcomes.

Impact of smoking on clinical outcomes in female patients with acute myocardial infarction

Background and Objectives

Cigarette smoking has been recognized as a prominent threat to women's health. We investigated the impact of smoking on clinical outcomes in Korean female patients after acute myocardial infarction (AMI).

Subjects and Methods

Out of the AMI patients who enrolled in the Korea AMI Registry, 4444 female patients were included in this study. Patients were divided into two groups-non-smoker and smoker-according to their current smoking status. We compared in-hospital mortality and major adverse cardiac events (MACE), including cardiac death, myocardial infarction, repeated percutaneous coronary intervention (PCI), or coronary artery bypass grafting during the one-year clinical follow-up period between two groups.

Results

The non-smoker group had more hypertension (HTN) and diabetes mellitus. The levels of total cholesterol, triglyceride, and low-density lipoprotein cholesterol were higher in the non-smoker group. However, in-hospital mortality was significantly higher in the smoker group (1.0% vs. 2.4%, p=0.002), and cardiac death during the 12-month clinical follow-up was significantly more frequent in the smoker group (2.2% vs. 4.5%, p=0.003). Total MACEs during the 12 months were higher in the smoker group (4.9% vs. 6.8%, p=0.014). Smoking and HTN were independent predictors of MACE {odds ratio (OR): 1.742, 95% confidence interval (CI): 1.010-3.000, p=0.046; OR: 1.573, 95% CI: 1.003-2.466, p=0.049, respectively}.

Conclusion

Female smokers with AMI showed significantly higher in-hospital mortality and MACE rates during the one-year clinical follow-up period.

Trends in educational inequalities in cause specific mortality in Norway from 1960 to 2010: a turning point for educational inequalities in cause specific mortality of Norwegian men after the millennium?

Background

Educational inequalities in total mortality in Norway have widened during 1960–2000. We wanted to investigate if inequalities have continued to increase in the post millennium decade, and which causes of deaths were the main drivers.

Methods

All deaths (total and cause specific) in the adult Norwegian population aged 45–74 years over five decades, until 2010 were included; in all 708,449 deaths and over 62 million person years. Two indices of inequalities were used to measure inequality and changes in inequalities over time, on the relative scale (Relative Index of Inequality, RII) and on the absolute scale (Slope Index of Inequality, SII).

Results

Relative inequalities in total mortality increased over the five decades in both genders. Among men absolute inequalities stabilized during 2000–2010, after steady, significant increases each decade back to the 1960s, while in women, absolute inequalities continued to increase significantly during the last decade. The stabilization in absolute inequalities among men in the last decade was mostly due to a fall in inequalities in cardiovascular disease (CVD) mortality and lung cancer and respiratory disease mortality. Still, in this last decade, the absolute inequalities in cause-specific mortality among men were mostly due to cardiovascular diseases (CVD) (34% of total mortality inequality), lung cancer and respiratory diseases (21%). Among women the absolute inequalities in mortality were mostly due to lung cancer and chronic lower respiratory tract diseases (30%) and CVD (27%).

Conclusions

In men, absolute inequalities in mortality have stopped increasing, seemingly due to reduction in inequalities in CVD mortality. Absolute inequality in mortality continues to widen among women, mostly due to death from lung cancer and chronic lung disease. Relative educational inequalities in mortality are still on the rise for Norwegian men and women.

A systematic review and meta-analysis of tobacco use and prostate cancer mortality and incidence in prospective cohort studies

CONTEXT

An association between tobacco smoking and prostate cancer (PCa) incidence and mortality was suggested in an earlier meta-analysis of 24 prospective studies in which dose-response associations and risks per unit of tobacco use were not examined.

OBJECTIVE

We investigated the association between several measures of tobacco use and PCa mortality (primary outcome) and incidence (secondary outcome) including dose-response association.

EVIDENCE ACQUISITION

Relevant articles from prospective studies were identified by searching the PubMed and Web of Science databases (through January 21, 2014) and reference lists of relevant articles. Combined relative risks (RRs) and 95% confidence intervals (CIs) were calculated using random effects methods. We also calculated population attributable risk (PAR) for smoking and PCa mortality.

EVIDENCE SYNTHESIS

We included 51 articles in this meta-analysis (11823 PCa deaths, 50349 incident cases, and 4,082,606 cohort participants). Current cigarette smoking was associated with an increased risk of PCa death (RR: 1.24; 95% CI, 1.18-1.31), with little evidence for heterogeneity and publication bias. The number of cigarettes smoked per day had a dose-response association with PCa mortality (p=0.02; RR for 20 cigarettes per day: 1.20). The PAR for cigarette smoking and PCa deaths in the United States and Europe were 6.7% and 9.5%, respectively, corresponding to >10000 deaths/year in these two regions. Current cigarette smoking was inversely associated with incident PCa (RR: 0.90; 95% CI, 0.85-0.96), with high heterogeneity in the results. However, in studies completed in 1995 or earlier (considered as completed before the prostate-specific antigen screening era), ever smoking showed a positive association with incident PCa (RR: 1.06; 95% CI, 1.00-1.12) with little heterogeneity.

CONCLUSIONS

Combined evidence from observational studies shows a modest but statistically significant association between cigarette smoking and fatal PCa. Smoking appears to be a modifiable risk factor for PCa death.

PATIENT SUMMARY

Smoking increases the chance of prostate cancer death. Not smoking prevents this harm and many other tobacco-related diseases.

The impact of life tables adjusted for smoking on the socio-economic difference in net survival for laryngeal and lung cancer

BACKGROUND

Net survival is a key measure in cancer control, but estimates for cancers that are strongly associated with smoking may be biased. General population life tables represent background mortality in net survival, but may not adequately reflect the higher mortality experienced by smokers.

METHODS

Life tables adjusted for smoking were developed, and their impact on net survival and inequalities in net survival for laryngeal and lung cancers was examined.

RESULTS

The 5-year net survival estimated with smoking-adjusted life tables was consistently higher than the survival estimated with unadjusted life tables: 7% higher for laryngeal cancer and 1.5% higher for lung cancer. The impact of using smoking-adjusted life tables was more pronounced in affluent patients; the deprivation gap in 5-year net survival for laryngeal cancer widened by 3%, from 11% to 14%.

CONCLUSIONS

Using smoking-adjusted life tables to estimate net survival has only a small impact on the deprivation gap in survival, even when inequalities are substantial. Adjusting for the higher, smoking-related background mortality did increase the estimates of net survival for all deprivation groups, and may be more important when measuring the public health impact of differences or changes in survival, such as avoidable deaths or crude probabilities of death.

Tobacco use disorder and the risk of suicide mortality

BACKGROUND AND AIMS

Tobacco use may be a risk factor for suicide mortality; however, prior research has produced equivocal findings and has been limited by relatively small sample sizes to study the rare event of suicide, as well as a lack of adjustment for other important factors, including psychiatric illness. We estimate the predictive association between tobacco use disorder and the risk of suicide mortality, adjusting for other important variables.

DESIGN

A prospective cohort study.

SETTING

The United States Veterans Health Administration (VHA).

PARTICIPANTS

All individuals who received VHA services in fiscal year (FY) 2005 and were alive at the start of FY 2006 (n = 4 863 086).

MEASUREMENTS

Tobacco use disorder was assessed via FYs 2004-05 VHA National Patient Care Database records. The outcome of suicide mortality was assessed during the follow-up interval from the beginning of FY 2006 to the end of FY 2008 using National Death Index records.

FINDINGS

Of the 4 863 086 individuals in the study, 4823 died by suicide during the follow-up interval. In the unadjusted model, tobacco use disorder was associated with an increased risk of suicide [hazard ratio (HR) = 1.88; 95% confidence interval (CI) = 1.76, 2.02]. After adjustment for model covariates, the association remained statistically significant, although attenuated (HR = 1.36, 95% CI = 1.27, 1.46).

CONCLUSIONS

Tobacco use disorder may confer a modest excess risk of death by suicide. Psychiatric disorders may partially explain the relationship between tobacco use disorder and suicide.

Cigarette smoking and completed suicide: results from 3 prospective cohorts of American adults

BACKGROUND

Prior reports have indicated a potential dose-response relationship between smoking and suicide. However, this relationship is controversial.

METHODS

This study evaluated the association between smoking and risk of death from suicide in three large-scale cohorts of U.S. men and women (n=253,033). Suicides were identified from death certificates among 43,816 men enrolled in the Health Professionals Follow-up Study (HPFS) between 1986 and 2008, 116,566 women in the Nurses' Health Study (NHS) between 1976 and 2008, and 92,651 women in the NHS II between 1989 and 2007. Information on smoking was obtained at baseline and updated every 2 years. Relative risks (RRs) of suicide were estimated using Cox proportional hazards regression models. Cohort specific RRs were pooled using random-effects models. Suicide deaths were determined by physician review of death certificates.

RESULTS

A total of 457 deaths from suicide were documented. Compared to never smokers, the pooled multivariate RR (95% confidence interval [CI]) of suicide was 1.15 (0.91-1.45) for former smokers and 2.69 (2.11-3.42) for current smokers. A nonmonotonic dose-response relationship was noted between the number of cigarettes smoked per day (CPD) and suicide risk (P trend<0.001). Compared to never smokers, the pooled multivariate RR (95% CI) was 2.59 (1.77-3.79) for those with 1-14 CPD, 2.03 (1.39-2.94) for those with 15-24 CPD, and 4.13 (2.96-5.78) for those with ≥ 25 CPD.

LIMITATIONS

Smoking was self-reported and had some degree of measurement error. Participants were not a representative sample of the U.S. population.

CONCLUSIONS

Results from three large cohorts suggest a nonmonotonic dose-response association between smoking and suicide risk.

Dose-response relationship of lung cancer to amount smoked, duration and age starting

AIM: To quantify smoking/lung cancer relationships accurately using parametric modelling.

METHODS: Using the International Epidemiological Studies on Smoking and Lung Cancer database of all epidemiological studies of 100+ lung cancer cases published before 2000, we analyzed 97 blocks of data for amount smoked, 35 for duration of smoking, and 27 for age started. Pseudo-numbers of cases and controls (or at risk) estimated from RRs by dose level formed the data modelled. We fitted various models relating log_e RR to dose (d), including βd, βd^Y and βlog_e (1 + Wd), and investigated goodness-of-fit and heterogeneity between studies.

RESULTS: The best-fitting models for log_e RR were 0.833 log_e [1 + (8.1c/10)] for cigarettes/d (c), 0.792 (y/10)^0.74 for years smoked (y) and 0.176 [(70 - a)/10]^1.44 for age of start (a). Each model fitted well overall, though some blocks misfitted. RRs rose from 3.86 to 22.31 between c = 10 and 50, from 2.21 to 13.54 between y = 10 and 50, and from 3.66 to 8.94 between a = 30 and 12.5. Heterogeneity (P < 0.001) existed by continent for amount, RRs for 50 cigarettes/d being 7.23 (Asia), 26.36 (North America) and 22.16 (Europe). Little heterogeneity was seen for duration of smoking or age started.

CONCLUSION: The models describe the dose-relationships well, though may be biased by factors including misclassification of smoking status and dose.

Risk of colorectal cancer associated with active smoking among female teachers

PURPOSE

The objective of this study was to examine the risk of colorectal cancer associated with active smoking among members of the California Teachers Study (CTS), a large cohort of female public school employees for whom highly detailed smoking information is available.

METHODS

The analysis was conducted among the 122,264 CTS participants who lived in California at cohort entry in 1995/1996, had no prior history of colorectal cancer, and provided detailed smoking information. 1,205 cases of invasive colorectal cancer prospectively diagnosed in 1995-2009 were identified from the California Cancer Registry, including 650 in the proximal colon, 267 in the distal colon, and 288 in the rectum. Hazard ratios and 95% confidence intervals were estimated using Cox proportional hazards models, stratified by age at cohort entry, and adjusted for race/ethnicity.

RESULTS

Compared to never smokers, current smokers had an approximately 30% increased risk of colorectal cancer. Overall, a slightly elevated risk was also noted for former smokers. Among former smokers, risks appeared to remain elevated for up to 20 years following cessation. Risks among former and current smokers increased with greater intensity and duration of smoking. Little evidence for heterogeneity in risk was noted for colon versus rectal cancer or for different subsites within the colon.

CONCLUSIONS

These results provide convincing evidence that heavy and/or long-term smoking is a risk factor for cancers of the colon and rectum. Such evidence should be considered when updating screening guidelines to include targeting people with long active smoking histories.

Cigarette smoking and risk of completed suicide: a meta-analysis of prospective cohort studies

BACKGROUND

Epidemiologic studies have reported conflicting results relating smoking to suicide risk. We conducted a meta-analysis of prospective cohort studies to evaluate the association of cigarette smoking with completed suicide.

METHODS

Eligible prospective cohort studies were identified from PubMed and EMbase databases (from 1966 to May 2011) and the reference lists of retrieved articles. Two authors independently extracted data and assessed study quality using the Newcastle-Ottawa Scale. Study-specific risk estimates were pooled using random-effects model and generalized least squares trend estimation was used to assess dose-response relationship.

RESULTS

Fifteen prospective cohort studies involving 2395 cases among 1,369,807 participants were included in the meta-analysis. Our data suggested that cigarette smoking significantly increased the risk of completed suicide. Compared with never smokers, the pooled RR was 1.28 (95% CI: 1.001-1.641) for former smokers, and 1.81 (95% CI: 1.50-2.19) for current smokers, respectively. Subgroup analyses showed that the increased suicide risk among current smokers appeared to be consistent, although there was heterogeneity among studies of current smoking (p < 0.001). Significant dose-response relationship was found between smoking and suicide, and the risk of suicide was increased by 24% for each increment of 10 cigarettes smoked per day (RR, 1.24; 95% CI: 1.20-1.28).

CONCLUSIONS

Our meta-analysis robustly demonstrates that cigarette smoking is associated with an increased risk of completed suicide, consistent with a dose-response relationship. This conclusion has an important public health message for countries with high smoking prevalence and high suicide rate such as China.

Systematic review with meta-analysis of the epidemiological evidence in the 1900s relating smoking to lung cancer

BACKGROUND

Smoking is a known lung cancer cause, but no detailed quantitative systematic review exists. We summarize evidence for various indices.

METHODS

Papers published before 2000 describing epidemiological studies involving 100+ lung cancer cases were obtained from Medline and other sources. Studies were classified as principal, or subsidiary where cases overlapped with principal studies. Data were extracted on design, exposures, histological types and confounder adjustment. RRs/ORs and 95% CIs were extracted for ever, current and ex smoking of cigarettes, pipes and cigars and indices of cigarette type and dose-response. Meta-analyses and meta-regressions investigated how relationships varied by study and RR characteristics, mainly for outcomes exactly or closely equivalent to all lung cancer, squamous cell carcinoma ("squamous") and adenocarcinoma ("adeno").

RESULTS

287 studies (20 subsidiary) were identified. Although RR estimates were markedly heterogeneous, the meta-analyses demonstrated a relationship of smoking with lung cancer risk, clearly seen for ever smoking (random-effects RR 5.50, CI 5.07-5.96) current smoking (8.43, 7.63-9.31), ex smoking (4.30, 3.93-4.71) and pipe/cigar only smoking (2.92, 2.38-3.57). It was stronger for squamous (current smoking RR 16.91, 13.14-21.76) than adeno (4.21, 3.32-5.34), and evident in both sexes (RRs somewhat higher in males), all continents (RRs highest for North America and lowest for Asia, particularly China), and both study types (RRs higher for prospective studies). Relationships were somewhat stronger in later starting and larger studies. RR estimates were similar in cigarette only and mixed smokers, and similar in smokers of pipes/cigars only, pipes only and cigars only. Exceptionally no increase in adeno risk was seen for pipe/cigar only smokers (0.93, 0.62-1.40). RRs were unrelated to mentholation, and higher for non-filter and handrolled cigarettes. RRs increased with amount smoked, duration, earlier starting age, tar level and fraction smoked and decreased with time quit. Relationships were strongest for small and squamous cell, intermediate for large cell and weakest for adenocarcinoma. Covariate-adjustment little affected RR estimates.

CONCLUSIONS

The association of lung cancer with smoking is strong, evident for all lung cancer types, dose-related and insensitive to covariate-adjustment. This emphasises the causal nature of the relationship. Our results quantify the relationships more precisely than previously.

Using the negative exponential distribution to quantitatively review the evidence on how rapidly the excess risk of ischaemic heart disease declines following quitting smoking

No previous review has formally modelled the decline in IHD risk following quitting smoking. From PubMed searches and other sources we identified 15 prospective and eight case-control studies that compared IHD risk in current smokers, never smokers, and quitters by time period of quit, some studies providing separate blocks of results by sex, age or amount smoked. For each of 41 independent blocks, we estimated, using the negative exponential model, the time, H, when the excess risk reduced to half that caused by smoking. Goodness-of-fit to the model was adequate for 35 blocks, others showing a non-monotonic pattern of decline following quitting, with a variable pattern of misfit. After omitting one block with a current smoker RR 1.0, the combined H estimate was 4.40 (95% CI 3.26-5.95) years. There was considerable heterogeneity, H being <2years for 10 blocks and >10years for 12. H increased (p<0.001) with mean age at study start, but not clearly with other factors. Sensitivity analyses allowing for reverse causation, or varying assumed midpoint times for the final open-ended quitting period little affected goodness-of-fit of the combined estimate. The US Surgeon-General's view that excess risk approximately halves after a year's abstinence seems over-optimistic.

HIV infection, aging and cardiovascular disease: epidemiology and prevention

In the developed world, HIV infection is now well managed with very effective and less toxic antiretroviral treatment. HIV-positive patients therefore are living longer, but are now faced by challenges associated with aging. Several non-AIDS associated morbidities are increased in this population, including cardiovascular disease (CVD). It is suggested that CVD occurs earlier among HIV-positive patients compared with HIV-negative patients, and at a higher rate. Several factors have been proposed to contribute to this. First, the traditional CVD risk factors are highly prevalent in this population. High rates of smoking, dyslipidaemia and a family history of CVD have been reported. This population is also aging, with estimates of more than 25% of HIV-positive patients in the developed world being over the age of 50. Antiretroviral treatment, both through its effect on lipids and through other, sometimes less well understood, mechanisms, has been linked to increased CVD risk. HIV infection, especially untreated, is a further contributing factor to increased CVD risk in HIV-positive patients. As the HIV-positive population continues to age, the risk of CVD will continue to increase. Guidelines for the management and prevention of CVD risk have been developed, and are largely modelled on those used in the general population. However, the data currently suggest that these interventions, such as the use of lipid-lowering medications and smoking cessation programs, remain quite low. A better understanding the mechanisms of CVD risk in this aging population and further efforts in improving uptake of prevention strategies will remain an important research area.

The effect of risky alcohol use and smoking on suicide risk: findings from the German MONICA/KORA-Augsburg Cohort Study

BACKGROUND

Smoking and heavy alcohol use predicts suicidal behaviour. Whether the simultaneous presentation of both conditions induces an amplified effect on risk prediction has not been investigated so far.

METHODS

In a community-based cohort study, a total of 12,888 subjects (6,456 men, 6,432 women; age range of 25-74 years at assessment) from three independent population-based cross-sectional MONICA surveys (conducted in 1984/85, 1989/90, and 1994/95), representative for the Southern German population, was followed up until 31 December 2002. Standardized mortality ratios (SMR) for deaths from suicide using German population rates were calculated for smoking and high alcohol consumption.

RESULTS

After a mean follow-up time of 12.0 (SD 4.4) years and 154,275 person-years at risk, a total of 1,449 persons had died from all causes and 38 of them from suicide. Compared to the general population, mortality from suicide was increased for risky alcohol consumption (SMR = 2.37; 95% CI 1.14-4.37) and for smoking (SMR = 2.30; 95% CI 1.36-3.63). A substantial increase in suicide mortality (SMR = 4.80; 95% CI 2.07-9.46) was observed for smokers with risky alcohol consumption.

CONCLUSIONS

The approximately fourfold increased relative risk for completed suicide in subjects with smoking and risky alcohol consumption indicates a synergistic effect which deserves an increased alertness.

Rates of cardiovascular disease following smoking cessation in patients with HIV infection: results from the D:A:D study(*)

OBJECTIVES

The aim of the study was to estimate the rates of cardiovascular disease (CVD) events after stopping smoking in patients with HIV infection.

METHODS

Patients who reported smoking status and no previous CVD prior to enrolment in the Data Collection on Adverse Events of Anti-HIV Drugs (D:A:D) study were included in this study. Smoking status is collected at each visit as current smoker (yes/no) and ever smoker (yes/no). Time since stopping smoking was calculated for persons who had reported current smoking during follow-up and no current smoking subsequently. Endpoints were: myocardial infarction (MI); coronary heart disease (CHD: MI plus invasive coronary artery procedure or death from other CHD); CVD (CHD plus carotid artery endarterectomy or stroke); and all-cause mortality. Event rates were calculated for never, previous and current smokers, and smokers who stopped during follow-up. Incidence rate ratios (IRRs) were determined using Poisson regression adjusted for age, sex, cohort, calendar year, family history of CVD, diabetes, lipids, blood pressure and antiretroviral treatment.

RESULTS

A total of 27 136 patients had smoking status reported, with totals of 432, 600, 746 and 1902 MI, CHD, CVD and mortality events, respectively. The adjusted IRR of CVD in patients who stopped smoking during follow-up decreased from 2.32 within the first year of stopping to 1.49 after >3 years compared with those who never smoked. Similar trends were observed for the MI and CHD endpoints. Reductions in risk were less pronounced for all-cause mortality.

CONCLUSION

The risk of CVD events in HIV-positive patients decreased with increasing time since stopping smoking. Smoking cessation efforts should be a priority in the management of HIV-positive patients.

Smoking and aggressive prostate cancer: a review of the epidemiologic evidence

Although tobacco use has been recognized as one of the leading causes of cancer morbidity and mortality, a role of smoking in the occurrence of prostate cancer has not been established. However, evidence indicates that factors that influence the incidence of prostate cancer may differ from those that influence progression and fatality from the disease. Thus, we reviewed and summarized results from prospective cohort studies that assessed the relation between smoking and fatal prostate cancer risk, as well as epidemiological and clinical studies that focused on aggressive behavior in prostate cancer, such as poorer survival, advanced stage, or poorer differentiation at diagnosis. The majority of the prospective cohort studies showed that current smoking is associated with a moderate increase of ~30% in fatal prostate cancer risk compared to never/non-smokers. This association is likely to be an underestimate of the effect of smoking because most studies had a single assessment of smoking at baseline and long follow-up times, and the association was considerably stronger in some sub-groups of heaviest smokers, or when smoking was assessed in a relatively short period (within 10 years) prior to cancer mortality. Using aggressive behavior of prostate cancer as outcome, current smoking was associated with significantly elevated risk, ranging from around twofold to threefold or higher. Although alternative explanations, such as publication bias, residual confounding, screening bias, and the influence of smoking-related comorbidities cannot be ruled out entirely, these findings suggest that smoking is associated with aggressive behavior of prostate cancers or with a sub-group of rapidly progressing prostate cancer. Based on evidence presented in this review, cigarette smoking is likely to be a risk factor for prostate cancer progression and should be considered as a relevant exposure in prostate cancer research and prevention of mortality from this cancer.

Systematic review with meta-analysis of the epidemiological evidence relating smoking to COPD, chronic bronchitis and emphysema

BACKGROUND

Smoking is a known cause of the outcomes COPD, chronic bronchitis (CB) and emphysema, but no previous systematic review exists. We summarize evidence for various smoking indices.

METHODS

Based on MEDLINE searches and other sources we obtained papers published to 2006 describing epidemiological studies relating incidence or prevalence of these outcomes to smoking. Studies in children or adolescents, or in populations at high respiratory disease risk or with co-existing diseases were excluded. Study-specific data were extracted on design, exposures and outcomes considered, and confounder adjustment. For each outcome RRs/ORs and 95% CIs were extracted for ever, current and ex smoking and various dose response indices, and meta-analyses and meta-regressions conducted to determine how relationships were modified by various study and RR characteristics.

RESULTS

Of 218 studies identified, 133 provide data for COPD, 101 for CB and 28 for emphysema. RR estimates are markedly heterogeneous. Based on random-effects meta-analyses of most-adjusted RR/ORs, estimates are elevated for ever smoking (COPD 2.89, CI 2.63-3.17, n = 129 RRs; CB 2.69, 2.50-2.90, n = 114; emphysema 4.51, 3.38-6.02, n = 28), current smoking (COPD 3.51, 3.08-3.99; CB 3.41, 3.13-3.72; emphysema 4.87, 2.83-8.41) and ex smoking (COPD 2.35, 2.11-2.63; CB 1.63, 1.50-1.78; emphysema 3.52, 2.51-4.94). For COPD, RRs are higher for males, for studies conducted in North America, for cigarette smoking rather than any product smoking, and where the unexposed base is never smoking any product, and are markedly lower when asthma is included in the COPD definition. Variations by sex, continent, smoking product and unexposed group are in the same direction for CB, but less clearly demonstrated. For all outcomes RRs are higher when based on mortality, and for COPD are markedly lower when based on lung function. For all outcomes, risk increases with amount smoked and pack-years. Limited data show risk decreases with increasing starting age for COPD and CB and with increasing quitting duration for COPD. No clear relationship is seen with duration of smoking.

CONCLUSIONS

The results confirm and quantify the causal relationships with smoking.

Smoking habits and the risk of non-fatal acute myocardial infarction in Costa Rica

BACKGROUND

Smoking is a major risk factor for cardiovascular diseases, but there is little information on Latin America.

METHODS

We used data from a case-control study comprising 2094 cases with a first acute non-fatal myocardial infarction (MI) and 2094 matched controls (by age, sex, and area of residence) living in Costa Rica between 1994 and 2004. Relative risks (RRs) were obtained from conditional logistic regression models.

RESULTS

Compared to never smokers, the risk of MI was not higher in ex-smokers, but the RR was 2.71 for current smokers, and increased with the number of cigarettes smoked per day. Smoking ≥25 cigarettes per day was associated with an eight-fold risk of MI. The RR was higher for women (4.39) than for men (2.38). There was no trend in risk with duration and age at starting smoking. RRs were respectively 4.8, 5.6 and 6.1 for smokers of ≥15 cigarettes per day with obesity, diabetes or hypertension compared to non-smokers. Subjects living with a smoker had a 23% higher MI risk. Active and passive smoking accounted for 38% and 8% of MI cases. It explained 25% and 9% of female and 42% and 7% of male cases, 47% and 15% of cases below age 50, and 35% and 5% cases above age 50 years. Stopping smoking reduced the risk of MI already after one year, and after five years the risk approached that of never smokers.

CONCLUSION

In Costa Rica, like elsewhere, inducing smokers to stop is a public health priority.

Tobacco smoking and colorectal cancer: a population-based case-control study in Newfoundland and Labrador

OBJECTIVE

Newfoundland and Labrador (NL) has the highest incidence rate of both colorectal cancer (CRC) and smoking prevalence in Canada. The objective of this study was to examine if CRC is associated with smoking in this population.

METHODS

Newly diagnosed cases identified between 1999 and 2003 were frequency-matched by 5-year age group and sex with controls selected from the residents of NL through random digit dialing. A total of 702 cases and 717 controls consented to participate in the study and completed a set of self-administered questionnaires. Measures of tobacco use included type of tobacco, age of initiation of smoking, years of smoking, years since started smoking, number of cigarettes smoked daily, pack years, and years since abstention from smoking. Odds ratios were estimated using multivariate logistic regression.

RESULTS

In comparison with non-smokers, former and current smokers were at a significantly elevated risk of CRC with corresponding odds ratios of 1.36 and 1.96. The risk significantly increased with cigarette smoking years, the amount of cigarettes smoked daily, and cigarette pack years. The risk significantly decreased with years of abstention from smoking cigarettes. This association was stronger among drinkers and in men. In addition, this effect was observed to be slightly stronger for rectum than colon cancer.

DISCUSSION

In summary, cigarette smoking increased the risk of CRC in the NL population. The risk of CRC associated with cigarette smoking varies by sex, drinking status, and site of CRC.

Women and tobacco dependence

Millions of American girls and women have been drawn to smoking by an industry that has been clearly and systematically targeting women of all ages and life circumstances. Tobacco marketing strategies skillfully link cigarette use to typical female values. Biologically speaking, women are especially vulnerable to the legion of health problems of tobacco use. Smoking is a critical hazard for women in their reproductive years, particularly when they are pregnant.

Medical history, body size, and cigarette smoking in relation to fatal prostate cancer

OBJECTIVES

Prostate cancer has few known risk factors. As part of a population-based case-control study conducted in four health maintenance organizations, the authors examined the associations between fatal prostate cancer and several medical and behavioral characteristics.

METHODS

Cases were 768 health plan members who died of prostate adenocarcinoma during the period 1997-2001. We randomly selected controls (929) from the health plan membership and matched them to cases on health plan, age, race, and pattern of health plan membership. We examined medical records to obtain information on potential risk factors during the 10 years before the date on which prostate cancer was first suspected; the same reference date was used for the matched controls.

RESULTS

Anthropometric characteristics, as well as personal histories of benign prostatic hypertrophy, transurethral prostatectomy, cancer, diabetes, prostatitis, hypertension, and vasectomy were largely similar for cases and controls. Men who died from prostate cancer were more likely than controls to have been cigarette smokers according to the most recent smoking notation before the reference date (odds ratio 1.5, 95% confidence interval 1.1-2.0).

CONCLUSIONS

The observed increase in risk associated with recent cigarette smoking is consistent with the findings of several other studies. However, in contrast with some reports, we observed no connection between fatal prostate cancer and some prior health conditions or measures of body size.

Consequences of smoking during pregnancy on maternal health

OBJECTIVE

To estimate the incidence of maternal cardiovascular and pulmonary events and the prevalence of other comorbid conditions among pregnant smokers.

METHODS

We queried the Nationwide Inpatient Sample (NIS) from the Healthcare Cost and Utilization Project (HCUP) of the Agency for Healthcare Research and Quality (AHRQ) for pregnancy-related discharge codes for the years 2000-2004. The prevalence of various conditions and the incidence of various complications were compared between smokers and nonsmokers.

RESULTS

The majority of smokers were young and white and had public insurance. Smokers were more likely to have experienced deep vein thrombosis (odds ratio [OR] 1.3, 95% confidence interval [CI] 1.1, 1.6), stroke (OR 1.7, 95% CI 1.2, 2.5), pulmonary embolus (OR 2.5, 95% CI 2.1, 3.0), and myocardial infarction (OR 4.6, 95% CI 3.3, 6.4). They were 3 times more likely to have experienced influenza or pneumonia (OR 2.9, 95% CI 2.7, 3.2) and 15 times more likely to have bronchitis (OR 15.2, 95% CI 12.8, 18.2). They were more likely to suffer from a number of comorbidities, including asthma (OR 4.0, 95% CI 3.7, 4.2) and gastrointestinal ulcers (OR 3.7, 95% CI 2.6, 5.5). Although they were less likely to have experienced gestational diabetes (OR 0.9, 95% CI 0.9, 1.0), preeclampsia (OR 0.8, 95% CI 0.8, 0.9), or eclampsia (OR 0.7, 95% CI 0.6, 0.9), they were more than 5 times as likely to have experienced an ectopic pregnancy (OR 5.4, 95% CI 4.6, 6.3).

CONCLUSIONS

Smoking has a negative impact on maternal health. Counseling about the risks of smoking in pregnancy should include not only fetal risks but maternal risks as well.

Smoking as a risk factor for prostate cancer: a meta-analysis of 24 prospective cohort studies

OBJECTIVES

We evaluated the relationship between smoking and adenocarcinoma of the prostate.

METHODS

We pooled data from 24 cohort studies enrolling 21 579 prostate cancer case participants for a general variance-based meta-analysis. Summary relative risks (RRs) and 95% confidence intervals (CIs) were calculated separately for mortality and incidence studies. We tested the robustness of effect measures and evaluated statistical heterogeneity with sensitivity analyses.

RESULTS

In the pooled data, current smokers had no increased risk of incident prostate cancer (RR = 1.04; 95% CI = 0.87, 1.24), but in data stratified by amount smoked they had statistically significant elevated risk (cigarettes per day or years: RR = 1.22; 95% CI = 1.01, 1.46; pack years of smoking: RR = 1.11; 95% CI = 1.01, 1.22). Former smokers had an increased risk (RR = 1.09; 95% CI = 1.02, 1.16). Current smokers had an increased risk of fatal prostate cancer (RR = 1.14; 95% CI = 1.06, 1.19). The heaviest smokers had a 24% to 30% greater risk of death from prostate cancer than did nonsmokers.

CONCLUSIONS

Observational cohort studies show an association of smoking with prostate cancer incidence and mortality. Ill-defined exposure categories in many cohort studies suggest that pooled data underestimate risk.

Cigarette smoking and colorectal cancer incidence and mortality: systematic review and meta-analysis

The association between cigarette smoking and colorectal cancer (CRC) has been controversial. To synthesize the available data, we conducted a comprehensive meta-analysis of all prospective studies. A total of 36 studies were included in our meta-analysis. We examined the association between smoking and CRC, colon cancer and rectal cancer in terms of incidence and mortality. Separate analyses were conducted for smoking status, daily cigarette consumption, duration, pack-years and age of initiation. Relative to nonsmokers, current and former smokers had a significantly increased risk of CRC incidence and mortality, respectively. When CRC data were combined with colon/rectal cancer data, current smokers had a significantly increased risk of CRC incidence. All 4 dose-response variables examined-daily cigarette consumption (RR = 1.38 for an increase of 40 cigarettes/day), duration (RR = 1.20 for an increase of 40 years of duration), pack-years (RR = 1.51 for an increase of 60 pack-years) and age of initiation (RR = 0.96 for a delay of 10 years in smoking initiation)-were significantly associated with CRC incidence (all p-values < 0.0001). The relationship between duration of smoking and rectal cancer incidence was also significant. Among the subset of studies that distinguished cancer by site, a higher risk was seen for rectal cancer than for colon cancer for all analyses. Among prospective studies, a consistent association exists between smoking and CRC. The association is stronger for rectal cancer than for colon cancer in the subset of studies that differentiated cancer by site.

Cardiorespiratory risk factors as predictors of 40-year mortality in women and men

OBJECTIVE

Most historical studies of cardiorespiratory risk factors as predictors of mortality have been based on men. This study examines whether they predict mortality over long periods in women and men.

DESIGN

Prospective cohort study.

SETTING

Participants were employees of the General Post Office.

METHODS

Risk factor data were collected via clinical examination and questionnaire, 1966-7. Associations between cardiorespiratory risk factors and 40-year mortality were determined for 644 women and 1272 men aged 35-70 at examination.

MAIN OUTCOME MEASURES

All-cause, cardiovascular (CVD), cancer and respiratory mortality.

RESULTS

Associations between systolic blood pressure and all-cause and stroke mortality were equally strong for women and men, hazard ratio (95% confidence interval) 1.25 (1.1 to 1.4) and 1.18 (1.1 to 1.3); and 2.17 (1.7 to 2.8) and 1.69 (1.4 to 2.1), respectively. Cholesterol was higher in women and was associated with all-cause 1.22 (1.1 to 1.4) and CVD 1.39 (1.2 to 1.7) mortality, while associations between 2-hour glucose and all-cause 1.15 (1.1 to 1.2), coronary heart disease (CHD) 1.25 (1.1 to 1.4) and respiratory mortality 1.21 (1.0 to 1.5) were observed in men. Obesity was associated with stroke in women (2.42 (1.12 to 5.24)) and CHD in men (1.59 (1.02 to 2.49)), while ECG ischaemia was associated with CVD in both sexes. The strongest, most consistent predictor of mortality was smoking in women and poor lung function in men. However, evidence of sex differences in associations between the cardiorespiratory risk factors measured and mortality was sparse.

CONCLUSIONS

Data from a 40-year follow-up period show remarkably persistent associations between risk factors and cardiorespiratory and all-cause mortality in women and men.

Smoking differently modifies suicide risk of affective disorders, substance use disorders, and social factors

BACKGROUND

Although an association between smoking and suicide has repeatedly been shown, information about a modifying influence of smoking on other risk factors for suicide is lacking.

METHODS

Axis I and Axis II disorders, sociodemographic factors, and tobacco use were assessed by a semi-structured interview including the Structured Clinical Interview for DSM-IV Axis I (SCID-I) and Personality Disorders (SCID-II) in 163 suicides (mean age 49.6+/-19.3 years; 64.4% men;) by psychological autopsy method and by personal interview in 396 living population-based control persons (mean age 51.6+/-17.0 years; 55.8% men).

RESULTS

Smoking status (current smokers, lifetime non-smokers, and former smokers) differently modifies the effects of psychiatric disorders and sociodemographic variables on suicide risk. Former and current smoking modified suicide risk associated with affective disorders, but only current smoking increased suicide risk for substance use disorders. Ex-smokers with affective disorders, particularly with major depression, had less increased suicide risk than current smokers and non-smokers with affective disorders. Estimated suicide risks for personality disorders and 'no professional training' were strongly increased by smoking.

LIMITATIONS

Due to the small size of some of the subgroups, confidence intervals are wide. Therefore, precise risk estimation is not possible.

CONCLUSIONS

Clinicians should interpret smoking as an indicator of increased risk of suicide for individuals with substance use disorders, personality disorders, and adverse social factors. Further studies are needed to investigate the effects of smoking cessation on suicide risk of patients with psychiatric disorders such as major depression and substance use disorders.

Lifestyle, genes, and cancer

It is estimated that almost 1.5 million people in the USA are diagnosed with cancer every year. However, due to the substantial effect of modifiable lifestyle factors on the most prevalent cancers, it has been estimated that 50% of cancer is preventable. Physical activity, weight loss, and a reduction in alcohol use can strongly be recommended for the reduction of breast cancer risk. Similarly, weight loss, physical activity, and cessation of tobacco use are important behavior changes to reduce colorectal cancer risk, along with the potential benefit for the reduction of red meat consumption and the increase in folic acid intake. Smoking cessation is still the most important prevention intervention for reducing lung cancer risk, but recent evidence indicates that increasing physical activity may also be an important prevention intervention for this disease. The potential benefit of lifestyle change to reduce prostate cancer risk is growing, with recent evidence indicating the importance of a diet rich in tomato-based foods and weight loss. Also, in the cancers for which there are established lifestyle risk factors, such as physical inactivity for breast cancer and obesity for colorectal cancer, there is emerging information on the role that genetics plays in interacting with these factors, as well as the interaction of combinations of lifestyle factors. Integration of genetic information into lifestyle factors can help to clarify the causal relationships between lifestyle and genetic factors and assist in better identifying cancer risk, ultimately leading to better-informed choices about effective methods to enhance health and prevent cancer.

Substance use disorders and risk for completed suicide

Substance use disorders are among the most frequent psychiatric disorders found in suicides. In psychological autopsy studies between 19% and 63% of all suicides suffered from substance use disorders, mostly from alcohol use disorders. Suicide risk is highly increased in substance use disorders, particularly in alcohol use disorders, and in co-morbid alcoholism and depression. So far, some risk factors for suicide have been identified in alcoholism. Nevertheless, various questions about the relationship between substance use disorders and suicide remain open, which indicate directions for future research.