Secondhand smoke exposure and survival following acute coronary syndrome: prospective cohort study of 1261 consecutive admissions among never-smokers

Relation between secondhand smoke exposure and cardiovascular risk factors in never smokers

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Objective:

Secondhand smoke exposure (SHSE) in nonsmokers has been associated with premature cardiovascular mortality and ischemic heart disease. We conducted a cross-sectional, population-based study evaluating the relationship between SHSE, measured by subjective and objective methods, and conventional cardiovascular risks such as blood pressure, lipid profiles, and fasting glucose.

Methods:

We extracted information on 7376 healthy adults who had never smoked, for whom there were available urine cotinine levels, from the Korea National Health and Nutrition Examination Survey 2008–2011. SHSE was defined using self-report questionnaires and urine cotinine levels. The main outcomes included SBP and DBP, serum lipid profiles, and fasting glucose.

Results:

The mean age of the study population was 45.4 ± 0.4 years and 75.2% were women. Self-reported SHSE had no significant association with study outcomes except for DBP, which had marginally positive relationships (P = 0.060). Unadjusted analysis showed higher cotinine levels were associated with lower SBP, total cholesterol, LDL cholesterol, and triglyceride. All associations lost statistical significance after multivariable adjustment. Fasting glucose had a positive relationship with urine cotinine in quartiles but not with logarithm-transformed cotinine.

Conclusion:

Although SHSE is associated with increased risk of cardiovascular mortality and morbidity, we did not find any consistent relationship among SHSE and blood pressure, lipid, or fasting glucose levels in this cross-sectional study. Using objective measurements of urine cotinine did not alter this relationship. Further long-term prospective studies are needed to evaluate the effect of SHSE as a cardiovascular risk factor.

Cigarette Smoking and Oxidative Stress in Patients with Coronary Artery Disease

AIM:

To determine whether cigarette smoking, as a risk factor for CAD, affects (anti)oxidant status.

MATERIAL AND METHODS:

The study included patients with CAD, divided according to their smoking status and the number of cigarettes smoked during a day. Biological markers of oxidative stress (concentration of oxidants and activity of antioxidant enzymes) were measured in all subjects.

RESULTS:

The study included 300 patients with CAD, (average age of 63 ± 11 years), predominantly males. Of the total, 34.0% were active smokers, 23.0% were former smokers, and 43.0% were non-smokers. Most of the active smokers smoked 1-20 cigarettes/day. In terms of concentration of oxidants (MDA and HP) there was not a significant difference between smokers versus non-smokers. As for the activity of antioxidant enzymes (SOD, CAT and GPX), a statistically significant difference was found in the activity of GPX among the active smokers with CAD and the non-smokers with CAD (p = 0.039).

CONCLUSION:

Smoking as a risk factor for CAD is closely associated with increased oxidative stress, and the number of cigarettes smoked plays an important role in increasing the level of oxidative damage and reducing antioxidant defence.

Legislative smoking bans for reducing harms from secondhand smoke exposure, smoking prevalence and tobacco consumption

BACKGROUND

Smoking bans have been implemented in a variety of settings, as well as being part of policy in many jurisdictions to protect the public and employees from the harmful effects of secondhand smoke (SHS). They also offer the potential to influence social norms and the smoking behaviour of those populations they affect. Since the first version of this review in 2010, more countries have introduced national smoking legislation banning indoor smoking.

OBJECTIVES

To assess the effects of legislative smoking bans on (1) morbidity and mortality from exposure to secondhand smoke, and (2) smoking prevalence and tobacco consumption.

SEARCH METHODS

We searched the Cochrane Tobacco Addiction Group Specialised Register, MEDLINE, EMBASE, PsycINFO, CINAHL and reference lists of included studies. We also checked websites of various organisations. Date of most recent search; February 2015.

SELECTION CRITERIA

We considered studies that reported legislative smoking bans affecting populations. The minimum standard was having an indoor smoking ban explicitly in the study and a minimum of six months follow-up for measures of smoking behaviour. Our search included a broad range of research designs including: randomized controlled trials, quasi-experimental studies (i.e. non-randomized controlled studies), controlled before-and-after studies, interrupted time series as defined by the Cochrane Effective Practice and Organisation of Care Group, and uncontrolled pre- and post-ban data.

DATA COLLECTION AND ANALYSIS

One author extracted characteristics and content of the interventions, participants, outcomes and methods of the included studies and a second author checked the details. We extracted health and smoking behaviour outcomes. We did not attempt a meta-analysis due to the heterogeneity in design and content of the studies included. We evaluated the studies using qualitative narrative synthesis.

MAIN RESULTS

There are 77 studies included in this updated review. We retained 12 studies from the original review and identified 65 new studies. Evidence from 21 countries is provided in this update, an increase of eight countries from the original review. The nature of the intervention precludes randomized controlled trials. Thirty-six studies used an interrupted time series study design, 23 studies use a controlled before-and-after design and 18 studies are before-and-after studies with no control group; six of these studies use a cohort design. Seventy-two studies reported health outcomes, including cardiovascular (44), respiratory (21), and perinatal outcomes (7). Eleven studies reported national mortality rates for smoking-related diseases. A number of the studies report multiple health outcomes. There is consistent evidence of a positive impact of national smoking bans on improving cardiovascular health outcomes, and reducing mortality for associated smoking-related illnesses. Effects on respiratory and perinatal health were less consistent. We found 24 studies evaluating the impact of national smoke-free legislation on smoking behaviour. Evidence of an impact of legislative bans on smoking prevalence and tobacco consumption is inconsistent, with some studies not detecting additional long-term change in existing trends in prevalence.

AUTHORS' CONCLUSIONS

Since the first version of this review was published, the current evidence provides more robust support for the previous conclusions that the introduction of a legislative smoking ban does lead to improved health outcomes through reduction in SHS for countries and their populations. The clearest evidence is observed in reduced admissions for acute coronary syndrome. There is evidence of reduced mortality from smoking-related illnesses at a national level. There is inconsistent evidence of an impact on respiratory and perinatal health outcomes, and on smoking prevalence and tobacco consumption.

An intervention to address secondhand tobacco smoke exposure among nonsmokers hospitalized with coronary heart disease

Secondhand tobacco smoke (SHS) exposure increases nonsmokers' risk of coronary heart disease and worsens outcomes after hospitalization for acute coronary syndrome, but it is rarely addressed in inpatient cardiac care. We developed and assessed a hospital-based intervention to increase nonsmokers' awareness of SHS as a cardiovascular risk factor. Nonsmokers admitted to 2 cardiac units of a large Boston, Massachusetts, hospital were surveyed before (May 2010 to January 2011) and after (November 2011 to March 2012) a system-level nurse-delivered intervention was implemented in October 2011. It consisted of a revised admission form that prompted nurses to document SHS exposure at admission, provide a pamphlet about SHS risks, and advise nonsmokers to make their home and car smoke free. The primary outcome was patients' short-term recall of advice to keep their home and car smoke free. The secondary outcome was patients' awareness of the cardiovascular risk of SHS exposure. We enrolled 190 nonsmokers before and 142 nonsmokers after implementation. Adjusting for group differences, patients admitted after the system change were more likely to recall being asked if a household member smokes (24% vs 10%, adjusted odds ratio [AOR] 3.6, 95% confidence interval [CI] 1.8 to 7.1, p=0.0002) and being advised to keep their home and car smoke free (28% vs 2%, AOR 27.3, 95% CI 7.8 to 95.7, p<0.0001). After the intervention, more patients believed that SHS exposure increased cardiovascular risk for nonsmokers (42% vs 21%, AOR 2.6, 95% CI 1.6 to 4.4) and for themselves (39% vs 22%, AOR 2.2, 95% CI 1.3 to 3.8). In conclusion, a system-level intervention in cardiac units successfully increased hospitalized nonsmokers' awareness of the cardiovascular risk of SHS exposure.

Epidemiology and public health policy of tobacco use and cardiovascular disorders in low- and middle-income countries

All forms of tobacco lead to an increased risk of cardiovascular disorders. During the past few decades, the number of people who consume tobacco has increased worldwide because of an overall increase in the global population. It is estimated that close to 80% of the >1.3 billion people who smoke tobacco in the world are in low- and middle-income countries. Smokeless forms of tobacco are also widely consumed in low- and middle-income countries, including chewable and snuffed forms. Lack of targeted and effective strategies to control tobacco consumption contributes to a large burden of cardiovascular disorders in low- and middle-income countries, where cardiovascular disorders have become the leading cause of morbidity and mortality. In this review, we evaluate the epidemiology of tobacco use in low- and middle-income countries and assess the public health policies needed to control tobacco use in such regions for the prevention of cardiovascular disorders and other tobacco-related morbidities and mortality.

Modeling the effects of indoor passive smoking at home, work, or other households on adult cardiovascular and mental health: the Scottish Health Survey, 2008-2011

Passive smoking has contributed increased risks of cardiovascular disease, mental health, and mortality, but the cumulative effects from work or other households were less studied. Therefore, it was aimed to model the effects of indoor passive smoking from own home, work, and other households in a country-wide, population-based setting. Data in the Scottish Health Survey between 2008 and 2011 after the law banning smoking in public places were analyzed. Information including demographics, lifestyle factors, and self-reported cardiovascular disease and mental health was obtained by household interview. Analyses included chi-square test and survey-weighted logistic regression modeling. After full adjustment, it was observed that being exposed to indoor passive smoking, in particular in more than two places of exposure, was significantly associated with risks of stroke, angina, heart attack, abnormal heart rhythms, and GHQ ≥ 12. The significance remained for angina, GHQ ≥ 12 and probably heart attack in never smokers. The cumulative risks also impacted on sleep problems, self-recognition, making decisions, self-confidence, under strain constantly, depressed, happiness and self-worth. The significance remained for sleep problems, self-confidence, under strain constantly, depressed, and happiness in never smokers. Elimination of indoor passive smoking from different sources should still be a focus in future public health programs.

Association between exposure to environmental tobacco smoke and biomarkers of oxidative stress among patients hospitalised with acute myocardial infarction

OBJECTIVE

To determine whether exposure to environmental tobacco smoke was associated with oxidative stress among patients hospitalised for acute myocardial infarction.

DESIGN

An existing cohort study of 1,261 patients hospitalised for acute myocardial infarction.

SETTING

Nine acute hospitals in Scotland.

PARTICIPANTS

Sixty never smokers who had been exposed to environmental tobacco smoke (admission serum cotinine ≥3.0 ng/mL) were compared with 60 never smokers who had not (admission serum cotinine ≤0.1 ng/mL).

INTERVENTION

None.

MAIN OUTCOME MEASURES

Three biomarkers of oxidative stress (protein carbonyl, malondialdehyde (MDA) and oxidised low-density lipoprotein (ox-LDL)) were measured on admission blood samples and adjusted for potential confounders.

RESULTS

After adjusting for baseline differences in age, sex and socioeconomic status, exposure to environmental tobacco smoke was associated with serum concentrations of both protein carbonyl (beta coefficient 7.96, 95% CI 0.76, 15.17, p = 0.031) and MDA (beta coefficient 10.57, 95% CI 4.32, 16.81, p = 0.001) but not ox-LDL (beta coefficient 2.14, 95% CI -8.94, 13.21, p = 0.703).

CONCLUSIONS

Exposure to environmental tobacco smoke was associated with increased oxidative stress. Further studies are requires to explore the role of oxidative stress in the association between environmental tobacco smoke and myocardial infarction.

Secondhand tobacco smoke exposure and heart rate variability and inflammation among non-smoking construction workers: a repeated measures study

BACKGROUND

Although it has been well recognized that exposure to secondhand tobacco smoke (SHS) is associated with cardiovascular mortality, the mechanisms and time course by which SHS exposure may lead to cardiovascular effects are still being explored.

METHODS

Non-smoking workers were recruited from a local union and monitored inside a union hall while exposed to SHS over approximately 6 hours. Participants were fitted with a continuous electrocardiographic monitor upon enrollment which was removed at the end of a 24-hr monitoring period. A repeated measures study design was used where resting ECGs and blood samples were taken from individuals before SHS exposure (baseline), immediately following SHS exposure (post) and the morning following SHS exposure (next-morning).Inflammatory markers, including high sensitivity C-reactive protein (CRP) and white blood cell count (WBC) were analyzed. Heart rate variability (HRV) was analyzed from the ECG recordings in time (SDNN, rMSSD) and frequency (LF, HF) domain parameters over 5-minute periods. SHS exposure was quantified using a personal fine particulate matter (PM2.5) monitor.Linear mixed effects regression models were used to examine within-person changes in inflammatory and HRV parameters across the 3 time periods. Exposure-response relationships with PM2.5 were examined using mixed effects models. All models were adjusted for age, BMI and circadian variation.

RESULTS

A total of 32 male non-smokers were monitored between June 2010 and June 2012. The mean PM2.5 from SHS exposure was 132 μg/m3. Immediately following SHS exposure, a 100 μg/m3 increase in PM2.5 was associated with declines in HRV (7.8% [standard error (SE) =3%] SDNN, 8.0% (SE = 3.9%) rMSSD, 17.2% (SE = 6.3%) LF, 29.0% (SE = 10.1%) HF) and increases in WBC count 0.42 (SE = 0.14) k/μl. Eighteen hours following SHS exposure, a 100 μg/m3 increase in PM2.5 was associated with 24.2% higher CRP levels.

CONCLUSIONS

Our study suggest that short-term SHS exposure is associated with significantly lower HRV and higher levels of inflammatory markers. Exposure-associated declines in HRV were observed immediately following exposure while higher levels of CRP were not observed until 18 hours following exposure. Cardiovascular autonomic and inflammation responses may contribute to the pathophysiologic pathways that link SHS exposure with adverse cardiovascular outcomes.

Second-hand tobacco smoke and cardiovascular disease risk: an epidemiological review

In this review, we have sought to examine the epidemiological, basic science, and public health data regarding the association between second-hand smoke (SHS) exposure and the development of coronary heart disease (CHD). SHS increases the risk of CHD by 25-30% according to multiple cohort, case-control, and meta-analytical studies. Physiologic and basic science research suggest that the mechanisms by which SHS affects the cardiovascular system are multiple and include increased thrombogenesis and low-density lipoprotein oxidation, decreased exercise tolerance, dysfunctional flow-mediated vasodilatation, and activation of inflammatory pathways with concomitant oxidative damage and impaired vascular repair. As a result, chronic exposure promotes atherogenesis and the development of cardiovascular disease, increasing the risk of having an acute coronary syndrome (ACS). With the implementation of statewide and nationwide public smoke-free legislation across the United States and Europe, respectively, over the last 10-15 years, there has been a significant and reciprocal decline in the incidence of emergency admissions for ACS by an average 17% despite persistent attempts on the part of the tobacco industry to diminish the correlation between SHS exposure and CHD. These findings underscore the importance of the effects of smoking legislation on community health.

Gender differences in acute coronary syndrome in Arab Emirati women--implications for clinical management

Gender differences exist in many aspects of acute coronary syndrome (ACS), including presentation and delay in diagnosis and treatment. The aim of the study was to evaluate gender-related differences in ACS patients in the United Arab Emirates (UAE). We analyzed a subset (n = 1697) of the Gulf Registry of Acute Coronary Events (Gulf RACE) data collected in 2007 of patients with ACS from 18 UAE hospitals. Women were significantly older (mean age: 64.0 ± 12.4 years for females and 50.9 ± 10.6 years for males, P < .001), more often had cardiac risk factors and were significantly less treated with β-blockers and reperfusion therapy. The adjusted mortality rate of women was 4.6% versus 1.2% in men (P < .001). Heart failure was higher in females compared with men (24.6% vs 12.5%; P < .001). Reasons for the high in-hospital mortality in women need to be investigated further.

What are candidate biobehavioral mechanisms underlying the association between secondhand smoke exposure and mental health?

There is a consistent positive and significant association between secondhand smoke exposure and mental health outcomes in the literature. There are potential genetic and behavioral confounders (e.g., psychological stress, maternal depression, and family functioning) were discussed, as well as potential causal neurobiological pathways (e.g., dopamine system). Further neurobiological research to establish causal pathways is needed as well as the integration of positive observational findings into clinical and public health prevention practices.

The case for a worldwide ban on smoking in public places

PURPOSE OF REVIEW

Second-hand smoke (SHS) is a major cause of morbidity and mortality on a global scale. Governments have increasingly sought to mitigate the effects of SHS by introducing legislation that restricts tobacco consumption in public places. There is emerging evidence that such legislation leads to direct and indirect health benefits.

RECENT FINDINGS

Exposure to SHS is now shown to be associated with development of cardiovascular disease, and poorer health outcomes in patients with established chronic obstructive pulmonary disease. Childhood (including in-utero) exposure to SHS has recently been linked with increased risk of cleft palate, demonstrable signs of atherosclerosis, and the development of emphysema and lung cancer in adulthood. Comprehensive bans on smoking in public lead to a reduction in overall exposure to SHS for both adults and children and have also been shown to immediately attenuate the incidence of myocardial infarction and paediatric hospital attendances with acute asthma.

SUMMARY

Banning smoking in public places is an effective tool for reducing tobacco-related morbidity across a multiplicity of diseases. Countries that have not already done so should introduce legislation to enforce effective legislation that prohibits smoking in public places.

Recent contributions of air- and biomarkers to the control of secondhand smoke (SHS): a review

Since the publication of the US Surgeon General Reports in 1996 and 2006 and the report of the California Environmental Protection Agency in 1999, many reports have appeared on the contribution of air and biomarkers to different facets of the secondhand smoke (SHS) issue, which are the targets of this review. These recent studies have allowed earlier epidemiological surveys to be biologically validated, and their plausibility demonstrated, quantified the levels of exposure to SHS before the bans in various environments, showed the deficiencies of mechanical control methods and of partial bans and the frequently correct implementation of the efficient total bans. More stringent regulation remains necessary in the public domain (workplaces, hospitality venues, transport sector, etc.) in many countries. Personal voluntary protection efforts against SHS are also needed in the private domain (homes, private cars). The effects of SHS on the cardiovascular, respiratory and neuropsychic systems, on pregnancy and fertility, on cancers and on SHS genotoxicity are confirmed through experimental human studies and through the relationship between markers and prevalence of disease or of markers of disease risk.

Legislative smoking bans for reducing secondhand smoke exposure, smoking prevalence and tobacco consumption

BACKGROUND

Smoking bans have been implemented in a variety of settings, as well as being part of policy in many jurisdictions to protect the public and employees from the harmful effects of secondhand smoke (SHS). They also offer the potential to influence social norms and smoking behaviour of those populations they affect.

OBJECTIVES

To assess the extent to which legislation-based smoking bans or restrictions reduce exposure to SHS, help people who smoke to reduce tobacco consumption or lower smoking prevalence and affect the health of those in areas which have a ban or restriction in place.

SEARCH STRATEGY

We searched the Cochrane Tobacco Addiction Group Specialised Register, MEDLINE, EMBASE, PsycINFO, CINAHL, Conference Paper Index, and reference lists and bibliographies of included studies. We also checked websites of various organisations. Date of most recent search; July 1st 2009.

SELECTION CRITERIA

We considered studies that reported legislative smoking bans and restrictions affecting populations. The minimum standard was having a ban explicitly in the study and a minimum of six months follow-up for measures of smoking behaviour. We included randomized controlled trials, quasi-experimental studies (i.e. non-randomized controlled studies), controlled before and after studies, interrupted-time series as defined by the Cochrane Effective Practice and Organization of Care Group, and uncontrolled pre- and post-ban data.

DATA COLLECTION AND ANALYSIS

Characteristics and content of the interventions, participants, outcomes and methods of the included studies were extracted by one author and checked by a second. Because of heterogeneity in the design and content of the studies, we did not attempt a meta-analysis. We evaluated the studies using qualitative narrative synthesis.

MAIN RESULTS

There were 50 studies included in this review. Thirty-one studies reported exposure to secondhand smoke (SHS) with 19 studies measuring it using biomarkers. There was consistent evidence that smoking bans reduced exposure to SHS in workplaces, restaurants, pubs and in public places. There was a greater reduction in exposure to SHS in hospitality workers compared to the general population. We failed to detect any difference in self-reported exposure to SHS in cars. There was no change in either the prevalence or duration of reported exposure to SHS in the home as a result of implementing legislative bans. Twenty-three studies reported measures of active smoking, often as a co-variable rather than an end-point in itself, with no consistent evidence of a reduction in smoking prevalence attributable to the ban. Total tobacco consumption was reduced in studies where prevalence declined. Twenty-five studies reported health indicators as an outcome. Self-reported respiratory and sensory symptoms were measured in 12 studies, with lung function measured in five of them. There was consistent evidence of a reduction in hospital admissions for cardiac events as well as an improvement in some health indicators after the ban.

AUTHORS' CONCLUSIONS

Introduction of a legislative smoking ban does lead to a reduction in exposure to passive smoking. Hospitality workers experienced a greater reduction in exposure to SHS after implementing the ban compared to the general population. There is limited evidence about the impact on active smoking but the trend is downwards. There is some evidence of an improvement in health outcomes. The strongest evidence is the reduction seen in admissions for acute coronary syndrome. There is an increase in support for and compliance with smoking bans after the legislation.

Changes in U.S. hospitalization and mortality rates following smoking bans

U.S. state and local governments have increasingly adopted restrictions on smoking in public places. This paper analyzes nationally representative databases, including the Nationwide Inpatient Sample, to compare short-term changes in mortality and hospitalization rates in smoking-restricted regions with control regions. In contrast with smaller regional studies, we find that smoking bans are not associated with statistically significant short-term declines in mortality or hospital admissions for myocardial infarction or other diseases. An analysis simulating smaller studies using subsamples reveals that large short-term increases in myocardial infarction incidence following a smoking ban are as common as the large decreases reported in the published literature.