Environmental tobacco smoke and ischemic heart disease

Impact of Scotland's comprehensive, smoke-free legislation on stroke

Background

Previous studies have reported a reduction in acute coronary events following smoke-free legislation. Evidence is lacking on whether stroke is also reduced. The aim was to determine whether the incidence of stroke, overall and by sub-type, fell following introduction of smoke-free legislation across Scotland on 26 March 2006.

Methods and Findings

A negative binomial regression model was used to determine whether the introduction of smoke-free legislation resulted in a step and/or slope change in stroke incidence. The model was adjusted for age-group, sex, socioeconomic deprivation quintile, urban/rural residence and month. Interaction tests were also performed. Routine hospital administrative data and death certificates were used to identify all hospital admissions and pre-hospital deaths due to stroke (ICD10 codes I61, I63 and I64) in Scotland between 2000 and 2010 inclusive. Prior to the legislation, rates of all stroke, intracerebral haemorrhage and unspecified stroke were decreasing, whilst cerebral infarction was increasing at 0.97% per annum. Following the legislation, there was a dramatic fall in cerebral infarctions that persisted for around 20 months. No visible effect was observed for other types of stroke. The model confirmed an 8.90% (95% CI 4.85, 12.77, p<0.001) stepwise reduction in cerebral infarction at the time the legislation was implemented, after adjustment for potential confounders.

Conclusions

Following introduction of national, comprehensive smoke-free legislation there was a selective reduction in cerebral infarction that was not apparent in other types of stroke.

Smoking ban in public areas is associated with a reduced incidence of hospital admissions due to ST-elevation myocardial infarctions in non-smokers. Results from the Bremen STEMI Registry

INTRODUCTION

Laws banning tobacco smoking from public areas have been passed in several countries, including the region of Bremen, Germany at the end of 2007. The present study analyses the incidence of hospital admissions due to ST-elevation myocardial infarctions (STEMIs) before and after such a smoking ban was implemented, focusing on differences between smokers and non-smokers. In this respect, data of the Bremen STEMI Registry (BSR) give a complete epidemiological overview of a region in northwest Germany with approximately 800,000 inhabitants since all STEMIs are admitted to one central heart centre.

METHODS AND RESULTS

Between January 2006 and December 2010, data from the BSR was analysed focusing on date of admission, age, gender, and prior nicotine consumption. A total of 3545 patients with STEMI were admitted in the Bremen Heart Centre during this time period. Comparing 2006-2007 vs. 2008-2010, hence before and after the smoking ban, a 16% decrease of the number of STEMIs was observed: from a mean of 65 STEMI/month in 2006-2007 to 55/month in 2008-2010 (p < 0.01). The group of smokers showed a constant number of STEMIs: 25/month in 2006-2007 to 26/month in 2008-2010 (+4%, p = 0.8). However, in non-smokers, a significant reduction of STEMIs over time was found: 39/month in 2006-2007 to 29/month in 2008-2010 (-26%, p < 0.01). The decline of STEMIs in non-smokers was consistently observed in all age groups and both sexes. Adjusting for potentially confounding factors like hypertension, obesity, and diabetes mellitus did not explain the observed decline.

CONCLUSIONS

In the BSR, a significant decline of hospital admissions due to STEMIs in non-smokers was observed after the smoking ban in public areas came into force. No reduction of STEMI-related admissions was found in smokers. These results may be explained by the protection of non-smokers from passive smoking and the absence of such an effect in smokers by the dominant effect of active smoking.

Reductions in cardiovascular, cerebrovascular, and respiratory mortality following the national irish smoking ban: interrupted time-series analysis

Background

Previous studies have shown decreases in cardiovascular mortality following the implementation of comprehensive smoking bans. It is not known whether cerebrovascular or respiratory mortality decreases post-ban. On March 29, 2004, the Republic of Ireland became the first country in the world to implement a national workplace smoking ban. The aim of this study was to assess the effect of this policy on all-cause and cause-specific, non-trauma mortality.

Methods

A time-series epidemiologic assessment was conducted, utilizing Poisson regression to examine weekly age and gender-standardized rates for 215,878 non-trauma deaths in the Irish population, ages ≥35 years. The study period was from January 1, 2000, to December 31, 2007, with a post-ban follow-up of 3.75 years. All models were adjusted for time trend, season, influenza, and smoking prevalence.

Results

Following ban implementation, an immediate 13% decrease in all-cause mortality (RR: 0.87; 95% CI: 0.76–0.99), a 26% reduction in ischemic heart disease (IHD) (RR: 0.74; 95% CI: 0.63–0.88), a 32% reduction in stroke (RR: 0.68; 95% CI: 0.54–0.85), and a 38% reduction in chronic obstructive pulmonary disease (COPD) (RR: 0.62; 95% CI: 0.46–0.83) mortality was observed. Post-ban reductions in IHD, stroke, and COPD mortalities were seen in ages ≥65 years, but not in ages 35–64 years. COPD mortality reductions were found only in females (RR: 0.47; 95% CI: 0.32–0.70). Post-ban annual trend reductions were not detected for any smoking-related causes of death. Unadjusted estimates indicate that 3,726 (95% CI: 2,305–4,629) smoking-related deaths were likely prevented post-ban. Mortality decreases were primarily due to reductions in passive smoking.

Conclusions

The national Irish smoking ban was associated with immediate reductions in early mortality. Importantly, post-ban risk differences did not change with a longer follow-up period. This study corroborates previous evidence for cardiovascular causes, and is the first to demonstrate reductions in cerebrovascular and respiratory causes.

The biology behind the atherothrombotic effects of cigarette smoke

Cigarette smoke is an aerosol that contains >4,000 chemicals, including nicotine, carbon monoxide, acrolein, and oxidant compounds. Exposure to cigarette smoke induces multiple pathological effects in the endothelium, several of which are the result of oxidative stress initiated by reactive oxygen species, reactive nitrogen species, and other oxidant constituents of cigarette smoke. Cigarette-smoke exposure interferes adversely with the control of all stages of plaque formation and development and pathological thrombus formation. The reactive oxygen species in cigarette smoke contribute to oxidative stress, upregulation of inflammatory cytokines, and endothelial dysfunction, by reducing the bioavailability of nitric oxide. Plaque formation and the development of vulnerable plaques also result from exposure to cigarette smoke via the enhancement of inflammatory processes and the activation of matrix metalloproteases. Moreover, exposure to cigarette smoke results in platelet activation, stimulation of the coagulation cascade, and impairment of anticoagulative fibrinolysis. Many cigarette-smoke-mediated prothrombotic changes are quickly reversible upon smoking cessation. Public health efforts should urgently promote our understanding of current cigarette-smoke-induced cardiovascular pathology to encourage individuals to reduce their exposure to cigarette smoke and, therefore, the detrimental consequences of associated atherothrombotic disease.

Secondhand smoke exposure and osteoporosis in never-smoking postmenopausal women: the Fourth Korea National Health and Nutrition Examination Survey

SUMMARY

The association between secondhand smoke (SHS) exposure and lumbar and femoral neck osteoporosis was assessed in postmenopausal never-smoking Korean women. The presence of family members who actively smoked was associated with femoral neck osteoporosis. The number of cigarettes consumed by cohabitant smokers was positively associated with lumbar and femoral neck osteoporosis.

INTRODUCTION

This study aimed to assess the association between SHS and postmenopausal osteoporosis.

METHODS

Of 2,067 postmenopausal women (age, ≥55 years) participating in the Fourth Korea National Health and Nutrition Examination Survey, 925 never-smokers identified through interviews and urinary cotinine level verification were enrolled. Cross-sectional relationships between self-reported SHS exposure and osteoporosis of the lumbar vertebrae and femoral neck (defined using the World Health Organization T-score criteria) were investigated by bone densitometry.

RESULTS

Participants having actively smoking family members showed increased adjusted odds ratio (aOR) for femoral neck osteoporosis compared with participants not exposed to SHS (aOR, 3.68; 95 % confidence interval [CI], 1.23-10.92). Participants whose cohabitant smokers consumed any number of cigarettes per day showed increased occurrences for lumbar and femoral neck osteoporosis compared with the nonexposed group. Participants whose cohabitant smokers consumed ≥20 cigarettes/day showed increased aORs for lumbar (aOR, 5.40; 95 % CI, 1.04-28.04) and femoral neck (aOR, 4.35; 95 % CI, 1.07-17.68) osteoporosis compared with participants not exposed to SHS.

CONCLUSIONS

In postmenopausal never-smoking Korean women, exposure to SHS was positively associated with osteoporosis. This finding further emphasizes a need to identify vulnerable groups exposed to SHS to increase bone health.

Secondhand smoke exposure induces acutely airway acidification and oxidative stress

Previous studies have shown that secondhand smoke induces lung function impairment and increases proinflammatory cytokines. The aim of the present study was to evaluate the acute effects of secondhand smoke on airway acidification and airway oxidative stress in never-smokers. In a randomized controlled cross-over trial, 18 young healthy never-smokers were assessed at baseline and 0, 30, 60, 120, 180 and 240 min after one-hour secondhand smoke exposure at bar/restaurant levels. Exhaled NO and CO measurements, exhaled breath condensate collection (for pH, H(2)O(2) and NO(2)(-)/NO(3)(-) measurements) and spirometry were performed at all time-points. Secondhand smoke exposure induced increases in serum cotinine and exhaled CO that persisted until 240 min. Exhaled breath condensate pH decreased immediately after exposure (p < 0.001) and returned to baseline by 180 min, whereas H(2)O(2) increased at 120 min and remained increased at 240 min (p = 0.001). No changes in exhaled NO and NO(2)/NO(3) were observed, while decreases in FEV(1) (p < 0.001) and FEV(1)/FVC (p < 0.001) were observed after exposure and returned to baseline by 180 min. A 1-h exposure to secondhand smoke induced airway acidification and increased airway oxidative stress, accompanied by significant impairment of lung function. Despite the reversal in EBC pH and lung function, airway oxidative stress remained increased 4 h after the exposure. Clinical trial registration number (EudraCT): 2009-013545-28.

Low-dose nonlinear effects of smoking on coronary heart disease risk

Some recent discussions of adverse human health effects of active and passive smoking have suggested that low levels of exposure are disproportionately dangerous, so that "The effects of even brief (minutes to hours) passive smoking are often nearly as large (averaging 80% to 90%) as chronic active smoking" (Barnoya and Glantz, 2005). Recent epidemiological evidence (Teo et al., 2006) suggests a more linear relation. This paper reexamines the empirical relation between self-reported low levels of active smoking and risk of coronary heart disease (CHD) in public-domain data from the National Health and Nutrition Examination Survey (NHANES). Consistent with biological evidence on J-shaped and U-shaped relations between smoking-associated risk factors and CHD risks, we find that low levels of active smoking do not appear to be associated with increased CHD risk. Several methodological challenges in epidemiology may explain how model-derived estimates can predict low-dose linear or concave dose-response estimates, even if the empirical (i.e., data-based) relation does not show a clear increased risk at the lowest doses.

Cerium oxide nanoparticles inhibit oxidative stress and nuclear factor-κB activation in H9c2 cardiomyocytes exposed to cigarette smoke extract

Cigarette smoke contains and generates a large amount of reactive oxygen species (ROS) that affect normal cellular function and have pathogenic consequences in the cardiovascular system. Increased oxidative stress and inflammation are considered to be an important mechanism of cardiovascular injury induced by cigarette smoke. Antioxidants may serve as effective therapeutic agents against smoke-related cardiovascular disease. Because of the presence of oxygen vacancies on its surface and self-regenerative cycle of its dual oxidation states, Ce(3+) and Ce(4+), cerium oxide (CeO(2)) nanoparticles offer a potential to quench ROS in biological systems. In this study, we determined the ability of CeO(2) nanoparticles to protect against cigarette smoke extract (CSE)-induced oxidative stress and inflammation in cultured rat H9c2 cardiomyocytes. CeO(2) nanoparticles pretreatment of H9c2 cells resulted in significant inhibition of CSE-induced ROS production and cell death. Pretreatment of H9c2 cells with CeO(2) nanoparticles suppressed CSE-induced phosphorylation of IκBα, nuclear translocation of p65 subunit of nuclear factor-κB (NF-κB), and NF-κB reporter activity in H9c2 cells. CeO(2) nanoparticles pretreatment also resulted in a significant down-regulation of NF-κB-regulated inflammatory genes tumor necrosis factor-α, interleukin (IL)-1β, IL-6, and inducible nitric-oxide synthase and further inhibited CSE-induced depletion of antioxidant enzymes, such as copper zinc superoxide dismutase, manganese superoxide dismutase, and intracellular glutathione content. These results indicate that CeO(2) nanoparticles can inhibit CSE-induced cell damage via inhibition of ROS generation, NF-κB activation, inflammatory gene expression, and antioxidant depletion and may have a great potential for treatment of smoking-related diseases.

The role of smoking cessation in the prevention of coronary artery disease

Smoking (tobacco addiction) is the most significant of the modifiable cardiovascular risk factors. Mistakenly described as a "habit" or "behavioral choice," the onset of tobacco addiction quickly follows the acquisition of an ability to inhale cigarette smoke and is reflected in a transformation of neurophysiologic function and nicotine-receptor density. Thereafter, comfort and a degree of neurophysiologic "equanimity" require the regular administration of nicotine. Smokers inhale thousands of other chemicals, many of which play critical roles in the initiation and accentuation of atherosclerosis by influencing vasomotor activity, vascular dysfunction, oxidation of lipids, atheroma development, and thrombosis. Smoking cessation is a priority in the management of any patient with cardiovascular disease. The benefits of cessation accrue rapidly in such patients and have a pronounced effect on the likelihood of disease progression, hospital readmission, and mortality. All physicians must be familiar with the principles of cessation practice and be able to initiate smoking cessation attempts.

Exposure to acrolein by inhalation causes platelet activation

Acrolein is a common air pollutant that is present in high concentrations in wood, cotton, and tobacco smoke, automobile exhaust and industrial waste and emissions. Exposure to acrolein containing environmental pollutants such as tobacco smoke and automobile exhaust has been linked to the activation of the coagulation and hemostasis pathways and thereby to the predisposition of thrombotic events in human. To examine the effects of acrolein on platelets, adult male C57Bl/6 mice were subjected acute (5ppm for 6h) or sub-chronic (1ppm, 6h/day for 4days) acrolein inhalation exposures. The acute exposure to acrolein did not cause pulmonary inflammation and oxidative stress, dyslipidemia or induce liver damage or muscle injury. Platelet GSH levels in acrolein-exposed mice were comparable to controls, but acrolein-exposure increased the abundance of protein-acrolein adducts in platelets. Platelets isolated from mice, exposed to both acute and sub-chronic acrolein levels, showed increased ADP-induced platelet aggregation. Exposure to acrolein also led to an increase in the indices of platelet activation such as the formation of platelet-leukocyte aggregates in the blood, plasma PF4 levels, and increased platelet-fibrinogen binding. The bleeding time was decreased in acrolein exposed mice. Plasma levels of PF4 were also increased in mice exposed to environmental tobacco smoke. Similar to inhalation exposure, acrolein feeding to mice also increased platelet activation and established a pro-thrombotic state in mice. Together, our data suggest that acrolein is an important contributing factor to the pro-thrombotic risk in human exposure to pollutants such as tobacco smoke or automobile exhaust, or through dietary consumption.

Passive smoking is associated with lower serum HDL-C levels in school children

BACKGROUND

In recent years, a number of studies have reported that exposure to environmental tobacco smoke (ETS) reduces high-density lipoprotein cholesterol (HDL-C) levels in children, as well as in adults. Further, a number of countries have indicated that passive smoking increases the risk of early arteriosclerosis onset. Here, to evaluate the effects of ETS exposure, we conducted a cross-sectional epidemiological study on primary school children in Japan using answers from a questionnaire survey, as well as urine cotinine and lipid metabolism-related variable measurements.

METHODS

A total of 121 sixth-grade primary school children participated in this study by completing a questionnaire about their food intake, lifestyle and family smoking habits. Early in the morning, we also measured height, weight, blood pressure, serum levels of total cholesterol, triglyceride, HDL-C, and blood sugar, as well as urine levels of cotinine and creatinine under unfed conditions.

RESULTS

From the questionnaire, 40 and 81 children reported being exposed and not exposed to ETS, respectively. Serum HDL-C levels, which were adjusted for the degree of corpulence and exercise habits, were significantly lower in the passive smoker group than the non-passive-smoker group (65.3 and 72.1 mg/dL, respectively; P= 0.012). In addition, proportional differences in serum HDL-C levels were also observed based on the amount of cigarettes smoked at home by family members of the child.

CONCLUSIONS

Results suggest that ETS exposure at home is associated in a dose-related manner with lower serum HDL-C levels in primary school children. In addition, our results suggest that smoking in the presence of children who are not usually exposed to ETS increases the risk of arteriosclerosis. Given these findings, we strongly recommend the establishment of anti-passive-smoking measures.

Cardiovascular effect of bans on smoking in public places: a systematic review and meta-analysis

OBJECTIVES

A systematic review and a meta-analysis were performed to determine the association between public smoking bans and risk for hospital admission for acute myocardial infarction (AMI).

BACKGROUND

Secondhand smoke (SHS) is associated with a 30% increase in risk of AMI, which might be reduced by prohibiting smoking in work and public places.

METHODS

PubMed, EMBASE, and Google Scholar databases plus bibliographies of relevant studies and reviews were searched for peer-reviewed original articles published from January 1, 2004, through April 30, 2009, using the search terms "smoking ban" and "heart" or "myocardial infarct." Investigators supplied additional data. All published peer-reviewed original studies identified were included. Incidence rates of AMI per 100,000 person-years before and after implementation of the smoking bans and incidence rate ratios (IRRs) with 95% confidence intervals (CIs) were calculated. Random effects meta-analyses estimated the overall effect of the smoking bans. Funnel plot and meta-regression assessed heterogeneity among studies.

RESULTS

Using 11 reports from 10 study locations, AMI risk decreased by 17% overall (IRR: 0.83, 95% CI: 0.75 to 0.92), with the greatest effect among younger individuals and nonsmokers. The IRR incrementally decreased 26% for each year of observation after ban implementation.

CONCLUSIONS

Smoking bans in public places and workplaces are significantly associated with a reduction in AMI incidence, particularly if enforced over several years.

[Strategies for reducing risks in smoking: opportunity or threat]

The smoking control policies recommended by the World Health Organisation have achieved a slight decrease in smoking prevalence in the developed countries, although associated mortality is still very high. The use of tobacco products other than cigarettes and even medicinal nicotine (known as nicotine replacement therapy (NRT)) has been proposed as a risk reduction strategy. Among the tobacco products with less individual risk than cigarettes would be any type of tobacco without smoke (smokeless) with a low content in nitrosamines and modified cigarettes; both forms included under the PREP (Potentially Reduced Exposure Products) concept. The idea would be to promote these products among those who cannot quit smoking or wish to reduce their risk without giving up nicotine intake. The possible effects of risk reduction strategies, including PREP, on the decreased prevalence and morbidity and mortality are reviewed, and the possible implications that this measure could have in our country are analysed. Tobacco control measures in Spain are recent and still insufficient. Therefore, the current priority in Spain is the development of policies of control that have shown to more than effective. The marketing and advertising of new tobacco products, even with reduced potential risk, seems more a serious threat than an opportunity for the development of smoking control policies.

Association of metabolic syndrome with smoking and alcohol intake in Japanese men

INTRODUCTION

There have been conflicting findings on whether metabolic syndrome (MetS) is associated with smoking and alcohol intake. This study investigated the association of MetS with smoking and alcohol intake.

METHODS

MetS was defined according to the International Diabetes Federation criteria, and smoking and alcohol intake were evaluated for 1,215 Japanese male workers using a questionnaire. The association of MetS with smoking and alcohol intake was assessed using logistic regression after adjusting for potential confounders. Proportional analyses for the prevalence of MetS among smoking and alcohol intake were performed as well.

RESULTS

Among the subjects, 148 (12%) were diagnosed with MetS, 485 (40%) were smokers, and 954 (79%) were regular alcohol users. The prevalence of MetS was the highest (19%) in smokers who did not drink, followed by smokers who also drank (13%), nonsmokers who drank (12%), and those who neither smoked nor drank (7%). Smoking itself was positively related to MetS (odds ratio [OR] = 1.4; 95% CI = 1.1-2.1) and MetS components, including larger waist circumference (OR = 1.5; 95% CI = 1.2-1.9), elevated triglyceride (OR = 1.9; 95% CI = 1.4-2.4), and reduced high-density lipoprotein cholesterol (OR = 1.7; 95% CI = 1.1-2.7). Alcohol intake was not significantly related to MetS; it was positively correlated only to higher fasting plasma glucose (OR = 1.7; 95% CI = 1.1-2.6).

DISCUSSION

These results suggest that cigarette smoking is an independent risk factor for MetS, but the risk does not seem to be exaggerated by alcohol intake.

Global burden of disease from alcohol, illicit drugs and tobacco

The use of alcohol, tobacco and illicit drugs entails considerable burden of disease: in 2000, about 4% of the global burden as measured in disability adjusted life years was attributable to each alcohol and tobacco, and 0.8% to illicit drugs. The burden of alcohol in the above statistic was calculated as net burden, i.e. incorporating the protective health effects. Tobacco use was found to be the most important of 25 risk factors for developed countries in the comparative risk assessment underlying the data. It had the highest mortality risk of all the substance use categories, especially for the elderly. Alcohol use was also important in developed countries, but constituted the most important of all risk factors in emerging economies. Alcohol use affected younger people than tobacco, both in terms of disability and mortality. The burden of disease attributable to the use of legal substances clearly outweighed the use of illegal drugs. A large part of the substance-attributable burden would be avoidable if known effective interventions were implemented.

Environmental tobacco smoke and cardiometabolic risk in young children: results from a survey in south-west Germany

AIMS

We explored the association between exposure to environmental tobacco smoke (ETS) and various cardiometabolic biomarkers in 10-year-old children.

METHODS AND RESULTS

A population-based cross-sectional study was carried out. Data on ETS exposure and potential confounders were collected by parental questionnaire. Adiponectin, leptin, markers of inflammation, apolipoproteins (apo) AI and B, and lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) were measured. Linear and logistic regression models were applied using the 90th percentile as a cut-off point except for adiponectin and apoAI (10th percentile). In linear models, ETS exposure was significantly associated with increasing plasma concentrations of leptin, C-reactive protein, fibrinogen, interleukin (IL)-6, and Lp-PLA(2). When compared with none, ETS exposure of more than 10 cigarettes per day was associated with elevated concentrations of leptin (OR 6.40; 95% CI, 2.67-15.39), C-reactive protein (OR 3.17; 95% CI, 1.31-7.68), Lp-PLA(2) (OR 2.97 95% CI, 1.32-6.68), low adiponectin (OR 2.69; 95% CI, 1.10-6.57), and low apoAI (OR 4.48; 95% CI, 2.16-10.85). Increasing dose of ETS exposure was related to an increasing number of abnormal cardiometabolic markers.

CONCLUSION

Among children, ETS exposure was associated with a low-grade inflammatory response and altered markers of lipid metabolism, which may initiate atherosclerosis in early life. However, longitudinal studies are necessary to determine the potential causal relevance of these associations.

[Changes in the population smoking patterns: Barcelona, 1983-2006]

OBJECTIVE

To describe the distribution of smoking in the population and to assess existing trends.

SUBJECTS AND METHODS

Cross sectional study in a sample of the resident non-institutionalized population over 14 years of age (n = 6,050) in Barcelona (Catalonia, Spain) using the Health Survey of 2006 and comparing trends for 1983-2006 with previous surveys. Independent variables included sex and age. Dependent variables were having ever been a smoker, quitting, and being a current smoker. Prevalence and proportions were estimated, stratifying or adjusting for age.

RESULTS

The prevalence of daily smokers was 27.3% for men and 20.6% for women. Age groups smoking more were 25-34 years for men and 35-44 for women. From 1983 to 2006 the decline for men was sharp, and the prevalence for women is now decreasing. The change accelerated progressively for men, in absolute and relative terms. Estimating the probability of quitting for smokers, there was an increase in cessations over this period. The proportion of smokers of an older age is now much smaller.

CONCLUSIONS

The evolution of the smoking epidemic over the last years shows promising trends. Quit rates have increased, and the decline in prevalence increases among men and has started in women. Smokers are increasingly becoming a minority, although to improve public health it would be desirable to speed the process of change.

Cardiovascular benefits of smoking regulations: The effect of decreased exposure to passive smoking

OBJECTIVES

Decreases in population rates of acute myocardial infarction (AMI) have been repeatedly seen in the first months after the introduction of regulations banning smoking in public places. By decreasing the exposure to passive smoking and its acute cardiovascular effects, smoking regulations may cause an immediate drop in AMI incidence, beginning from the initial days after their introduction. Using simulations, we quantified this expected decrease.

METHODS

Expected AMI decreases were estimated using several parameters, including prevalence of exposure to passive and active smoking, relative risks of AMI associated with active and passive smoking, decrease in exposure to passive smoking after the introduction of the regulation, and level of susceptibility of active smokers to exposure to passive smoking.

RESULTS

After evaluating several possible combinations of these parameters, we found that AMI reductions of 5-15% seem likely. For example, a scenario with a population average of 5 hours per week of overall exposure to passive smoking, a 50% reduction in this exposure after the introduction of the regulation, an acute relative risk (RR) of AMI of 4.5 in the first hour after passive smoking exposure, and similar susceptibility to passive smoking among both active and passive smokers translates into a 8.6% decrease in AMI.

CONCLUSIONS

Smoking regulations can cause immediate and relevant decreases in AMI through the prevention of exposure to passive smoking.

Coronary heart disease attributable to passive smoking: CHD Policy Model

BACKGROUND

Passive smoking is a major risk factor for coronary heart disease (CHD), and existing estimates are out of date due to recent and substantial changes in the level of exposure.

OBJECTIVE

To estimate the annual clinical burden and cost of CHD treatment attributable to passive smoking.

OUTCOME MEASURES

Annual attributable CHD deaths, myocardial infarctions (MI), total CHD events, and the direct cost of CHD treatment.

METHODS

A Monte Carlo simulation estimated the CHD events and costs as a function of the prevalence of CHD risk factors, including passive-smoking prevalence and a low (1.26) and high (1.65) relative risk of CHD due to passive smoking. Estimates were calculated using the CHD Policy Model, calibrated to reproduce key CHD outcomes in the baseline Year 2000 in the U.S.

RESULTS

At 1999-2004 levels, passive smoking caused 21,800 (SE=2400) to 75,100 (SE=8000) CHD deaths and 38,100 (SE=4300) to 128,900 (SE=14,000) MIs annually, with a yearly CHD treatment cost of $1.8 (SE=$0.2) to $6.0 (SE=$0.7) billion. If recent trends in the reduction in the prevalence of passive smoking continue from 2000 to 2008, the burden would be reduced by approximately 25%-30%.

CONCLUSIONS

Passive smoking remains a substantial clinical and economic burden in the U.S.

Oxidative stress and accelerated vascular aging: implications for cigarette smoking

Cigarette smoking is the major cause of preventable morbidity and mortality in the United States and constitutes a major risk factor for atherosclerotic vascular disease, including coronary artery disease and stroke. Increasing evidence supports the hypothesis that oxidative stress and inflammation provide the pathophysiological link between cigarette smoking and CAD. Previous studies have shown that cigarette smoke activates leukocytes to release reactive oxygen and nitrogen species (ROS/RNS) and secrete pro-inflammatory cytokines, increases the adherence of monocytes to the endothelium and elicits airway inflammation. Here we present an overview of the direct effects of water-soluble cigarette smoke constituents on endothelial function, vascular ROS production and inflammatory gene expression. The potential pathogenetic role of peroxynitrite formation, and downstream mechanisms including poly(ADP-ribose) polymerase (PARP) activation in cardiovascular complications in smokers are also discussed.

Glutathione S-transferase polymorphisms, passive smoking, obesity, and heart rate variability in nonsmokers

BACKGROUND

Disturbances of heart rate variability (HRV) may represent one pathway by which second-hand smoke (SHS) and air pollutants affect cardiovascular morbidity and mortality. The mechanisms are poorly understood.

OBJECTIVES

We investigated the hypothesis that oxidative stress alters cardiac autonomic control. We studied the association of polymorphisms in oxidant-scavenging glutathione S-transferase (GST) genes and their interactions with SHS and obesity with HRV.

METHODS

A total of 1,133 nonsmokers > 50 years of age from a population-based Swiss cohort underwent ambulatory 24-hr electrocardiogram monitoring and reported on lifestyle and medical history. We genotyped GSTM1 and GSTT1 gene deletions and a GSTP1 (Ile105Val) single nucleotide polymorphism and analyzed genotype-HRV associations by multiple linear regressions.

RESULTS

Homozygous GSTT1 null genotypes exhibited an average 10% decrease in total power (TP) and low-frequency-domain HRV parameters. All three polymorphisms modified the cross-sectional associations of HRV with SHS and obesity. Homozygous GSTM1 null genotypes with > 2 hr/day of SHS exposure exhibited a 26% lower TP [95% confidence interval (CI), 11 to 39%], versus a reduction of -5% (95% CI, -22 to 17%) in subjects with the gene and the same SHS exposure compared with GSTM1 carriers without SHS exposure. Similarly, obese GSTM1 null genotypes had, on average, a 22% (95% CI, 12 to 31%) lower TP, whereas with the gene present obesity was associated with only a 3% decline (95% CI, -15% to 10%) compared with nonobese GSTM1 carriers.

CONCLUSIONS

GST deficiency is associated with significant HRV alterations in the general population. Its interaction with SHS and obesity in reducing HRV is consistent with an impact of oxidative stress on the autonomous nervous system.

Smoke-free legislation and hospitalizations for acute coronary syndrome

BACKGROUND

Previous studies have suggested a reduction in the total number of hospital admissions for acute coronary syndrome after the enactment of legislation banning smoking in public places. However, it is unknown whether the reduction in admissions involved nonsmokers, smokers, or both.

METHODS

Since the end of March 2006, smoking has been prohibited by law in all enclosed public places throughout Scotland. We collected information prospectively on smoking status and exposure to secondhand smoke based on questionnaires and biochemical findings from all patients admitted with acute coronary syndrome to nine Scottish hospitals during the 10-month period preceding the passage of the legislation and during the same period the next year. These hospitals accounted for 64% of admissions for acute coronary syndrome in Scotland, which has a population of 5.1 million.

RESULTS

Overall, the number of admissions for acute coronary syndrome decreased from 3235 to 2684--a 17% reduction (95% confidence interval, 16 to 18)--as compared with a 4% reduction in England (which has no such legislation) during the same period and a mean annual decrease of 3% (maximum decrease, 9%) in Scotland during the decade preceding the study. The reduction in the number of admissions was not due to an increase in the number of deaths of patients with acute coronary syndrome who were not admitted to the hospital; this latter number decreased by 6%. There was a 14% reduction in the number of admissions for acute coronary syndrome among smokers, a 19% reduction among former smokers, and a 21% reduction among persons who had never smoked. Persons who had never smoked reported a decrease in the weekly duration of exposure to secondhand smoke (P<0.001 by the chi-square test for trend) that was confirmed by a decrease in their geometric mean concentration of serum cotinine from 0.68 to 0.56 ng per milliliter (P<0.001 by the t-test).

CONCLUSIONS

The number of admissions for acute coronary syndrome decreased after the implementation of smoke-free legislation. A total of 67% of the decrease involved nonsmokers. However, fewer admissions among smokers also contributed to the overall reduction.

Smoking reduction fails to improve clinical and biological markers of cardiac disease: a randomized controlled trial

Cigarette reduction has been proposed as a treatment goal for smokers who are not interested in stopping completely. This randomized controlled trial was designed to determine the effect of a smoking reduction intervention on smoking behavior, symptoms of heart disease, and biomarkers of tobacco exposure. It included 152 patients with heart disease who did not intend to stop smoking in the next 30 days. Participants were randomly assigned to smoking reduction (SR) or usual care (UC). SR subjects received counseling and nicotine replacement therapy to encourage > or =50% reduction in cigarettes per day (CPD). They were followed at 1, 3, 6, 12 and 18 months to assess smoking, heart disease symptoms, quality of life and nicotine, cotinine, carbon monoxide (CO), white blood cell (WBC) count, fibrinogen, hs-C-reactive protein (hs-CRP), F2-isoprostane, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol and its glucuronides (total NNAL), and 1-hydroxypyrene (1-HOP). At 6 months SR participants reduced by 10.9 CPD, compared with 7.4 CPD in UC (difference NS). At 18 months, 9/78 SR vs. 9/74 UC participants quit smoking. There were no significant differences between treatment groups in angina, quality of life or adverse events, nicotine, cotinine, CO, WBC count, fibrinogen, hs-CRP, F2-isoprostane, total NNAL or 1-HOP levels at any time point. To determine if smoking reduction, regardless of treatment condition, was associated with improved outcomes, we compared all subjects at 6 months to baseline (mean reduction in CPD from 27.4 to 18.1, p<.01). There were no significant changes in outcome variables except CO, which decreased by 5.5 ppm (p<.01). There were also no significant improvements considering only subjects who reduced by > or =50%, or those who had no history of reduction prior to enrollment in the study. The SR intervention did not significantly reduce CPD or toxin exposure, or improve smoking cessation or clinical outcomes compared to UC. These results emphasize the importance of abstinence for smokers with heart disease to minimize health risks from tobacco.

Oncocalyxone A inhibits human platelet aggregation by increasing cGMP and by binding to GP Ibalpha glycoprotein

BACKGROUND AND PURPOSE

Oncocalyxone A (OncoA) has a concentration-dependent anti-platelet activity. The present study aimed to further understand the mechanisms related to this effect.

EXPERIMENTAL APPROACH

Human platelet aggregation was measured by means of a turbidimetric method. OncoA (32-256 microM) was tested against several platelet-aggregating agents, such as adenosine diphosphate (ADP), collagen, arachidonic acid (AA), ristocetin and thrombin.

KEY RESULTS

OncoA completely inhibited platelet aggregation with a calculated mean inhibitory concentration (IC50-microM) of 122 for ADP, 161 for collagen, 159 for AA, 169 for ristocetin and 85 for thrombin. The anti-aggregatory activity of OncoA was not inhibited by 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ). OncoA, at a concentration that caused no significant anti-aggregatory activity, potentiated sodium nitroprusside (SNP) anti-aggregatory activity (18.8+/-2.9%-SNP vs 85.0+/-8.2%-SNP+OncoA). The levels of nitric oxide (NO) or cAMP were not altered by OncoA while cGMP levels were increased more than 10-fold by OncoA in resting or ADP-activated platelets. Flow cytometry revealed that OncoA does not interact with receptors for fibrinogen, collagen or P-selectin. Nevertheless, OncoA decreased the binding of antibodies to GP Ibalpha, a glycoprotein that is related both to von Willebrand factor and to thrombin-induced platelet aggregation.

CONCLUSION AND IMPLICATIONS

OncoA showed anti-aggregatory activity in platelets that was associated with increased cGMP levels, not dependent on NO and with blocking GP Ibalpha glycoprotein. This new mechanism has the prospect of leading to new anti-thrombotic drugs.

Implications of a public smoking ban

OBJECTIVES

Legislation to ban smoking in public places is currently a major area of interest across Canada. The main objectives of the study were to 1) determine the effect of the smoking ban on incidence of acute myocardial infarction, 2) determine if the new legislation altered population-based smoking prevalence, and 3) measure public support for the public smoking ban.

METHODS

The city of Saskatoon initiated a public smoking ban on July 1, 2004. We retrospectively reviewed all hospital discharges for acute MI from July 2000 to June 2005. We reviewed CCHS survey information on smoking prevalence for Saskatoon, Saskatchewan and Canada from 2003 to 2005. We prospectively contacted 1,255 Saskatoon residents by telephone to determine support for the public smoking ban.

RESULTS

The age-standardized incidence rate of acute MI fell from 176.1 (95% CI 165.3-186.8) cases per 100,000 population (July 1, 2000 to June 30, 2004) to 152.4 (95% CI 135.3-169.3) cases per 100,000 population (July 1, 2004 to June 30, 2005). Smoking prevalence in Saskatoon fell from 24.1% in 2003 (95% CI 20.4-27.7) to 18.2% in 2005 (95% CI 15.7-20.9) while smoking prevalence in Saskatchewan remained unchanged at 23.8% (95% CI 22.6-25.3) and Canada reduced from 22.9% (95% CI 22.5-23.3) to 21.3% (95% CI 20.8-21.8). Seventy-nine percent of Saskatoon residents believed the smoking ban was a good idea.

INTERPRETATION

The public smoking ban in Saskatoon, Canada, is associated with reduced incidence rates of acute MI, lower smoking prevalence and high levels of public support.

Substance-attributable morbidity and mortality changes to Canada's epidemiological profile: measurable differences over a ten-year period

BACKGROUND

Substance use is responsible for a large burden of disease in Canada, however updated data are needed for health care planning and policy development. This study replicates and makes improvements on 1992 estimates of substance-attributable morbidity and mortality for the year 2002. There are two objectives, the main one being to compare the substance-attributable morbidity and mortality in 1992 with 2002 using the same methods of calculation, and the second, to compare the two different methods of estimating the substance-attributable mortality and morbidity in 2002.

METHOD

Estimates of substance-attributable burden were made by combining relative risk data with exposure prevalence data and disease-related mortality and morbidity information from national databases. First, identical relative risk estimates for 1992 were used with the 2002 data in order to draw direct comparisons. In a second analysis, updated relative risk and attributable disease information (post-1992) was used to better estimate the mortality and morbidity for Canada in 2002.

RESULTS

Overall, from 1992 to 2002, there were relative increases in substance-attributable mortality estimates for alcohol and illegal drugs, where the latter relatively increased more; and a relative decrease in tobacco-attributable mortality. In terms of absolute numbers in combined risk factors, deaths and hospital days for those under 70 years of age decreased mainly due to tobacco. Comparisons of the two methods showed that the updated method resulted in more conservative numbers than previous calculations.

INTERPRETATION

There is an unacceptably high burden of substance-attributable disease in Canada in the early 2000s. Exposure changes and epidemiological shifts in population and diseases over the last 10 years have affected where the burden lies, but it is still vital to incorporate policy-based initiatives that have proven to be effective in reducing substance-attributable burden in practice.

Smoking-attributable morbidity: acute care hospital diagnoses and days of treatment in Canada, 2002

Background

Smoking is one of the most important risk factors for burden of disease. Our objective was to estimate the number of hospital diagnoses and days of treatment attributable to smoking for Canada, 2002.

Methods

Distribution of exposure was taken from a major national survey of Canada, the Canadian Community Health Survey. For chronic diseases, risk relations were taken from the published literature and combined with exposure to calculate age- and sex-specific smoking-attributable fractions (SAFs). For fire deaths, SAFs were taken directly from available statistics. Information on morbidity, with cause of illness coded according to the International Classification of Diseases version 10, was obtained from the Canadian Institute for Health Information.

Results

For Canada in 2002, 339,179 of all hospital diagnoses were estimated to be attributable to smoking and 2,210,155 acute care hospital days. Ischaemic heart disease was the largest single category in terms of hospital days accounting for 21 percent, followed by lung cancer at 9 percent. Smoking-attributable acute care hospital days cost over $2.5 billion in Canada in 2002.

Conclusion

Since the last major project produced estimates of this type, the rate of hospital days per 100,000 population has decreased by 33.8 percent. Several possible factors may have contributed to the decline in the rate of smoking-attributable hospital days: a drop in smoking prevalence, a decline in overall hospital days, and a shift in distribution of disease categories. Smoking remains a significant health, social, and economic burden in Canada.

Prognostic factors for tobacco consumption reduction after relapse

INTRODUCTION

It is not properly estimated the cigarette consumption after a relapse compared with the consumption before a smoking cessation therapy. The aim of this study was to know if tobacco consumption among relapsed smokers that visited a smoking cessation unit is higher or lower than consumption preceding dishabituation therapy and the related factors to this consumption change.

SUBJECTS AND METHODS

1,516 smokers who received a multicomponent program for smoking cessation have been studied. The percentage of reduction after the relapse in relation to previous consumption and the consumption difference with regard to basal variables among 994 relapsed smokers has been calculated. A logistic regression model was used in order to analyze the predictors to reduce more than 50% of previous cigarette consumption.

RESULTS

Relapsed patients smoked 20.4% less than before the smoking cessation therapy. Smokers with chronic obstructive pulmonary disease, and with the age of 50 years or more, had the highest rate of reduction consumption. The best predictors for cigarette reduction were those of low nicotine dependence and being heavy smokers.

CONCLUSIONS

Heavy smokers or low nicotine dependence smokers have a higher probability to reduce their cigarette consumption. Other predictor variables are age of more than 50 years, high previous consumption or previous abstinence period of more than 6 months.

Trends in body mass index, blood pressure and parental smoking habits in middle socio-economic level Turkish adolescents

Patterns of cardiovascular risk factors in populations are not static over time. We examined trends in body mass index (BMI), parental smoking and blood pressure over a 15-year period in Turkish children aged 15-17 years. Two cross-sectional studies were performed in secondary schools in Turkey in 1989-1990 and 2004-2005. Study participants were 673 children in 1989-1990 and 640 adolescents in 2004-2005. Main outcome measures were weight, height, BMI, presence and amount of parental smoking, systolic and diastolic blood pressure. Age and sex matched comparisons were performed to assess temporal trends in these measures. Children in 2004-2005 had increased weight, height, BMI and decreased systolic and diastolic blood pressure in all age groups compared with children in 1989-1990. According to the international criteria, 3.4% of children were obese and 15.8% were overweight in 2005, compared to 0.7% obese and 4.2% overweight in 1990 (P<0.001). However, a decrease was noted in blood pressure; 16% were classified as hypertensive in 1989-1990 versus 8% in 2004-2005 (P<0.001). The prevalence and amount of parental smoking also decreased over the last 15 years. We observed significant changes in BMI and blood pressure in Turkish children over the last 15 years. Temporal trends in these parameters may indicate a change in the pattern of cardiovascular disease in this population.

The impact of a smoking ban on hospital admissions for coronary heart disease

OBJECTIVE

In March 2002, the city of Bowling Green, Ohio, implemented a clean indoor air ordinance banning smoking in workplaces and public places. This study evaluates the effect of this ordinance on hospital admissions for smoking-related diseases.

METHODS

A quasi-experimental design with interrupted time-series was used including a matched control city (Kent, Ohio) with no clean indoor air ordinance. Data on hospital admissions during the period of January 1999 to June 2005 were analyzed using Autoregressive Integrated Moving Average (ARIMA) models.

RESULTS

A reduction in admission rates for smoking-related diseases was achieved in Bowling Green compared to the control city. The largest reduction was for coronary heart disease, where rates were decreased significantly by 39% after 1 year and by 47% after 3 years following the implementation of the ordinance. ARIMA models revealed a statistically significant downward trend in monthly admission rates for coronary heart disease (Bowling Green, omega=-1.69, p=0.036 vs. Kent, omega=-1.14, p=0.183) and support the hypothesis that the ordinance had a significant impact on admission rates for coronary heart disease.

CONCLUSION

The findings of this study suggest that clean indoor air ordinances lead to a reduction in hospital admissions for coronary heart disease, thus reducing health care costs.

Selective hair analysis of nicotine by molecular imprinted solid-phase extraction: An application for evaluating tobacco smoke exposure

A method using a molecularly imprinted polymer (MIP) as the selective sorbent for solid-phase extraction (SPE) has been developed. Its application to the assay of hairy nicotine level among smokers and non-smokers with high-performance liquid chromatography (HPLC) and evaluation of exposures to the environmental tobacco smoke (ETS) were validated. The MIP was synthesized using nicotine as the template molecule and methacrylic acid (MAA) as the functional monomer. This MIP-SPE method provided inherent selectivity and a sensitive response to nicotine with a detection limit of 0.2 ng/ml hair at a signal-to-noise ratio of 3:1 and the limit of quantification was 0.5 ng/ml. The linearity was assessed in the range of 0.5-80 ng/ml hair, with a coefficient (r(2)) greater than 0.987. The amounts of nicotine determined in smokers and non-smokers hair were in the range of 5.1-69.5 ng/mg hair and 0.50-9.3 ng/mg hair, respectively. The reported measures of ETS exposure were significantly associated with hairy nicotine levels. This assay of nicotine in hair using MISPE provided a very selective and reliable method for the evaluation of the exposure to tobacco smoke.

Exposure to secondhand smoke and biomarkers of cardiovascular disease risk in never-smoking adults

BACKGROUND

Exposure to secondhand smoke has been associated with a disproportionately high risk of coronary heart disease, thought to be mediated through inflammation, platelet aggregation, and/or endothelial dysfunction. The epidemiological association between objectively measured exposure to secondhand smoke and biomarkers of heart disease risk has not been investigated, however.

METHODS AND RESULTS

We have investigated the cross-sectional relation between secondhand smoke exposure, measured objectively as cotinine, and recognized biomarkers of heart disease risk, namely C-reactive protein, homocysteine, fibrinogen, and white blood cell count, in 7599 never-smoking adults from the Third National Health and Nutrition Examination Survey. Compared with subjects with no detectable cotinine, those with detectable but low-level cotinine (range, 0.05 to 0.215 ng/mL) had significantly higher levels of both fibrinogen (adjusted mean difference, 8.9 mg/dL; 95% CI, 0.9 to 17.0; P=0.03) and homocysteine (0.8 micromol/L; 95% CI, 0.4 to 1.1; P<0.001) but not C-reactive protein or white blood cell count. Effect estimates of similar magnitude and significance were seen in subjects in the high category of cotinine exposure (>0.215 ng/mL). The increased levels of fibrinogen and homocysteine seen in relation to secondhand smoke exposure were equivalent to approximately 30% to 45% of those seen for active smoking.

CONCLUSIONS

Passive smokers appear to have disproportionately increased levels of 2 biomarkers of cardiovascular disease risk, fibrinogen and homocysteine. This finding provides further evidence to suggest that low-level exposure to secondhand smoke has a clinically important effect on susceptibility to cardiovascular disease.

Smoking and Aortic Diseases

Cigarette smoking is a major vascular risk factor and in this context, it is an independent risk factor for the development of aortic disease, especially the formation and growth of abdominal aortic aneurysms (AAA). Medline was searched up to January 31, 2007 for the relevant literature for this review of the mechanisms by which smoking causes aortic wall damage and its subsequent impact on the clinical manifestation of this process. Idiopathic AAAs and aortic dissection are considered, as well as other aortic diseases (eg, Takayasu, Kawasaki, Behcet and Buerger). There is evidence suggesting an abnormal homeostasis between proteolytic and antiproteolytic activity in the vascular wall during the development of AAAs, and these mechanisms can be influenced by smoking. Smoking cessation plays an important role in the management of aortic disease.

Tobacco, heart disease, and practical counseling

As a large part of the care for children is preventive health, knowledge about the effects of tobacco exposure, risk factors, prevention strategies, and intervention are important. Because most smokers begin smoking while being cared for by physicians who care for children, pediatricians are particularly well suited to identify those at risk and to provide meaningful prevention. As physicians, we need to also assist parents to quit smoking, thereby setting a good example to their children, while improving their health as well as that of their children. Likewise, when identifying a youth experimenting or regularly smoking tobacco, intervention needs to be offered through counseling, referral, or medical therapy.

Tobacco use and risk of myocardial infarction in 52 countries in the INTERHEART study: a case-control study

BACKGROUND

Tobacco use is one of the major avoidable causes of cardiovascular diseases. We aimed to assess the risks associated with tobacco use (both smoking and non-smoking) and second hand tobacco smoke (SHS) worldwide.

METHODS

We did a standardised case-control study of acute myocardial infarction (AMI) with 27,089 participants in 52 countries (12,461 cases, 14,637 controls). We assessed relation between risk of AMI and current or former smoking, type of tobacco, amount smoked, effect of smokeless tobacco, and exposure to SHS. We controlled for confounders such as differences in lifestyles between smokers and non-smokers.

FINDINGS

Current smoking was associated with a greater risk of non-fatal AMI (odds ratio [OR] 2.95, 95% CI 2.77-3.14, p<0.0001) compared with never smoking; risk increased by 5.6% for every additional cigarette smoked. The OR associated with former smoking fell to 1.87 (95% CI 1.55-2.24) within 3 years of quitting. A residual excess risk remained 20 or more years after quitting (1.22, 1.09-1.37). Exclusion of individuals exposed to SHS in the never smoker reference group raised the risk in former smokers by about 10%. Smoking beedies alone (indigenous to South Asia) was associated with increased risk (2.89, 2.11-3.96) similar to that associated with cigarette smoking. Chewing tobacco alone was associated with OR 2.23 (1.41-3.52), and smokers who also chewed tobacco had the highest increase in risk (4.09, 2.98-5.61). SHS was associated with a graded increase in risk related to exposure; OR was 1.24 (1.17-1.32) in individuals who were least exposed (1-7 h per week) and 1.62 (1.45-1.81) in people who were most exposed (>21 h per week). Young male current smokers had the highest population attributable risk (58.3%; 95% CI 55.0-61.6) and older women the lowest (6.2%, 4.1-9.2). Population attributable risk for exposure to SHS for more than 1 h per week in never smokers was 15.4% (12.1-19.3).

CONCLUSION

Tobacco use is one of the most important causes of AMI globally, especially in men. All forms of tobacco use, including different types of smoking and chewing tobacco and inhalation of SHS, should be discouraged to prevent cardiovascular diseases.

Exposure to environmental tobacco smoke in a general population

AIMS

To estimate how the level of exposure to environmental tobacco smoke (ETS) in pregnancy, childhood and adulthood vary with personal characteristics in a general population.

METHODS

In 1996/1997, a community sample of 3181 adults, aged 26-82, received a mailed questionnaire, to which 2819 subjects responded. The prevalences of ETS exposure were estimated according to sex, age, educational level, smoking, occupational dust or gas exposure and exposure to moulds. Logistic regression was used to estimate the adjusted odds ratios for the different ETS exposures with respect to these covariates.

RESULTS

Altogether 9% reported exposure to maternal smoking in foetal life and 23% in childhood. Fourteen percent reported current domestic ETS exposure, while 13% reported current occupational ETS. Occupational ETS exposure was more frequent among men (16%) than women (10%). The oldest subjects (61-82 years) reported less ETS exposures than the younger subjects. Current smokers and subjects with occupational dust or fumes exposure had a higher prevalence for all the ETS exposures compared to ex- and never smokers and subjects without occupational exposure, respectively.

CONCLUSION

From a general population sample male sex, younger age, current smoking, and occupational dust or fumes exposure were associated with higher level of ETS exposure.

Secondhand smoke as an acute threat for the cardiovascular system: a change in paradigm

The evidence that active smoking is a risk factor for cardiovascular disease (CVD) and the leading cause of preventable death is overwhelming. However, numerous epidemiological findings indicate that even passive exposure to cigarette smoke may exert detrimental effects on vascular homoeostasis. Recent experimental data provide a deeper insight into the pathophysiological mechanisms linking secondhand smoke (SHS) to CVD. Importantly, most of these effects appear to be characterized by a rapid onset. For example, the relatively low doses of toxins inhaled by passive smoking are sufficient to elicit acute endothelial dysfunction, and these effects may be related, at least in part, to the inactivation of nitric oxide. Moreover, passive smoking may directly impair the viability of endothelial cells and reduce the number and functional activity of circulating endothelial progenitor cells. In addition, platelets of non-smokers appear to be susceptible to pro-aggregatory changes with every passive smoke exposure. Overall, SHS induces oxidative stress and promotes vascular inflammation. Apart from vasoconstriction and thrombus formation, however, the myocardial oxygen balance is further impaired by SHS-induced adrenergic stimulation and autonomic dysfunction. These data strongly suggest that passive smoking is capable of precipitating acute manifestations of CVD (atherothrombosis) and may also have a negative impact on the outcome of patients who suffer acute coronary syndromes.

The impact of environmental tobacco smoke on women's risk of dying from heart disease: a meta-analysis

OBJECTIVE

To review systematically and analyze the association between environmental tobacco smoke (ETS) exposure and the risk of dying from heart disease in women.

METHODS

We searched the English-language literature using MEDLINE (1966-April 2004), CINAHL, PsychInfo, and bibliographies of selected studies. We included studies that specifically addressed the association of ETS and heart disease mortality in women and had adequate controls and retrievable risk estimates. We looked for either cohort studies or randomized controlled trials. Studies were evaluated independently by two of the authors. Nine cohort studies were finally selected for analysis. We estimated the summary relative risk (RR) and associated 95% confidence intervals (95% CI) using a random-effects model.

RESULTS

Mean follow-up periods for these cohorts ranged from 6 to 39 years. Among non-smoking women, exposure to ETS was associated with a 15% increase in the risk of dying from heart disease compared with nonsmoking women not exposed to ETS (RR = 1.15, 95% CI 1.03-1.28, p < 0.05).

CONCLUSIONS

Among nonsmoking women, exposure to passive smoke increases the risk of dying from heart disease. In accordance with the newly developed guidelines by the American Heart Association for prevention of cardiovascular disease (CVD) in women, we recommend counseling women on reducing or avoiding ETS exposure.

Effect of smoking on platelet count and platelet parameters: an observation

Arterial thrombosis occurs with increased frequency in cigarette smokers. It is believed that disturbance of platelet function, especially aggregation, is the essential mechanism responsible for this pathology. However, the effect of smoking on the quantity of platelets might be another contributing factor. The effect of smoking on platelet count is still controversial. We performed a cross section-al study to compare the platelet count and platelet parameters in Thai police who are smokers and non-smokers. A total of 30 Thai police in Bangkok were included in this study. Of the 30 police, there are 5 non-smokers and 25 smokers. The platelet counts and platelet parameters of the subjects were not significantly different between smokers and non-smokers.