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

Secondhand Smoking Is Associated With Vascular Inflammation

BACKGROUND

The relative risk for cardiovascular diseases in passive smokers is similar to that of active smokers despite almost a 100-fold lower dose of inhaled cigarette smoke. However, the mechanisms underlying the surprising susceptibility of the vascular tissue to the toxins in secondhand smoke (SHS) have not been directly investigated. The aim of this study was to investigate directly vascular endothelial cell function in passive smokers.

METHODS

Using a minimally invasive method of endothelial biopsy, we investigated directly the vascular endothelium in 23 healthy passive smokers, 25 healthy active smokers, and 23 healthy control subjects who had never smoked and had no regular exposure to SHS. Endothelial nitric oxide synthase (eNOS) function (expression of basal eNOS and activated eNOS [phosphorylated eNOS at serine1177 (P-eNOS)]) and expression of markers of inflammation (nuclear factor-κB [NF-κB]) and oxidative stress (nitrotyrosine) were assessed in freshly harvested venous endothelial cells by quantitative immunofluorescence.

RESULTS

Expression of eNOS and P-eNOS was similarly reduced and expression of NF-κB was similarly increased in passive and active smokers compared with control subjects. Expression of nitrotyrosine was greater in active smokers than control subjects and similar in passive and active smokers. Brachial artery flow-mediated dilation was similarly reduced in passive and active smokers compared with control subjects, consistent with reduced endothelial NO bioavailability.

CONCLUSIONS

Secondhand smoking increases vascular endothelial inflammation and reduces active eNOS to a similar extent as active cigarette smoking, indicating direct toxic effects of SHS on the vasculature.

Immediate effect of passive smoking on microcirculatory flow

OBJECTIVE

Exposure to SHS, as by passive smoking, seems to increase the incidence of cardiovascular events. It has been shown that active smoking of a single cigarette causes an immediate and significant decrease in microcirculatory blood flow velocity, whereas the acute effects of exposure to SHS on microcirculatory flow have as yet not been demonstrated.

METHODS

Healthy nonsmoking volunteers of both genders were studied during acute exposure to SHS of two cigarettes burning up to 10 minutes. Microvessels were examined by in vivo vital capillaroscopy (Capiflow(®)), allowing continuous assessment of CBV.

RESULTS

CBV decreased from 514 mm/sec (CI 383-646) at baseline to 306 mm/sec (CI 191-420) at end of SHS exposure with a further decrease to a nadir of 240 mm/sec (CI 155-325) four minutes after the end of this exposure (p < 0.0001; ANOVA).

CONCLUSIONS

The result of this study shows that passive inhalation of secondhand cigarette smoke induces an immediate and prolonged marked reduction in CBV in nonsmoking healthy volunteers.

Behavioral and Physiological Responses to Nicotine Patch Administration Among Nonsmokers Based on Acute and Chronic Secondhand Tobacco Smoke Exposure

INTRODUCTION

Despite the large amount that is known about the physical health effects of secondhand tobacco smoke (SHS) exposure, little is known about the behavioral health effects. Nicotine, the principle psychoactive substance in SHS, elicits subjective mood and physiological responses in nonsmokers. However, no studies have examined the subjective mood or physiological responses to nicotine in nonsmokers while accounting for prior chronic or acute SHS exposure.

METHODS

A 7-mg nicotine patch was administered to 17 adult nonsmokers for 2 hr. Main outcome measures obtained at ½ hr, 1 hr, and 2 hr were subjective behavioral drug effects (based on eleven 10-cm Visual Analog Scales [VASs]) and the physiological measures of heart rate, blood pressure, and serum nicotine levels. Analysis of outcome data was based on participants' chronic (using hair nicotine) or acute (using saliva cotinine) SHS exposure.

RESULTS

Greater chronic SHS exposure was negatively associated with pleasurable responses to nicotine administration ("drug feels good" score at 2-hr time point, Spearman's ρ = -.65, p < .004), whereas greater acute SHS exposure was associated with positive responses ("like feeling of drug" score at 2-hr time point, Spearman's ρ = .63, p < .01). There were no associations between chronic or acute exposure and physiological changes in response to nicotine administration.

DISCUSSION

The findings of this study may be useful in providing preliminary empirical data for future explorations of the mechanism whereby SHS exposure can influence behavioral outcomes in nonsmokers. Such studies can inform future interventions to reduce the physical and behavioral health risks associated with SHS exposure.

Association between salivary cotinine and cardiovascular biomarkers among nonsmokers and current smokers: cross-sectional study of 10,081 participants

OBJECTIVE

Both active smoking and exposure to secondhand smoke (SHS) are associated with cardiovascular disease, but sidestream smoke contains higher levels of small particles and toxic gases than mainstream smoke. The relationship between the concentration of cotinine and a number of cardiovascular biomarkers among nonsmokers and active smokers was examined.

METHODS

A cross-sectional study using the Scottish Health Surveys conducted between 1998 and 2010 was undertaken. Inclusion was restricted to participants aged ≥16 years who had provided saliva and blood samples. Uni- and multivariate regression models were used to examine the relationships between the concentration of cotinine and C-reactive protein (CRP), high-density lipoprotein (HDL) cholesterol, and fibrinogen concentrations, as well as total:HDL cholesterol ratios.

RESULTS

Of the 10,018 eligible participants, 7,345 (73.3%) were confirmed to be nonsmokers (cotinine <15.0 ng/mL) and 2,673 (26.7%) were confirmed to be current smokers (cotinine ≥15.0 ng/mL). CRP and total:HDL cholesterol increased, and HDL cholesterol decreased, with increasing cotinine concentration across nonsmokers and smokers (all p < .001). However, there were step changes at the interface, whereby nonsmokers with a high exposure to SHS had lower concentrations of cotinine than light active smokers but comparable concentrations of CRP (p = .709), HDL cholesterol (p = .931), and total:HDL cholesterol (p = .405). Fibrinogen concentrations were significantly raised in moderate and heavy active smokers only (both p < .001).

CONCLUSION

Exposure to SHS is associated with disproportionately higher biomarkers of cardiovascular risk compared with active smoking. Protection from exposure to SHS should be a public health priority.

Prevalence and impact of active and passive cigarette smoking in acute respiratory distress syndrome

OBJECTIVES

Cigarette smoke exposure has recently been found to be associated with increased susceptibility to trauma- and transfusion-associated acute respiratory distress syndrome. We sought to determine 1) the incidence of cigarette smoke exposure in a diverse multicenter sample of acute respiratory distress syndrome patients and 2) whether cigarette smoke exposure is associated with severity of lung injury and mortality in acute respiratory distress syndrome.

DESIGN

Analysis of the Albuterol for the Treatment of Acute Lung Injury and Omega Acute Respiratory Distress Syndrome Network studies.

SETTING

Acute Respiratory Distress Syndrome Network hospitals.

PATIENTS

Three hundred eighty-one patients with acute respiratory distress syndrome.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanol, a validated tobacco-specific marker, was measured in urine samples from subjects enrolled in two National Heart, Lung, and Blood Institute Acute Respiratory Distress Syndrome Network randomized controlled trials. Urine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol levels were consistent with active smoking in 36% of acute respiratory distress syndrome patients and with passive smoking in 41% of nonsmokers (vs 20% and 40% in general population, respectively). Patients with 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol levels in the active smoking range were younger and had a higher incidence of alcohol misuse, fewer comorbidities, lower severity of illness, and less septic shock at enrollment compared with patients with undetectable 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol levels. Despite this lower severity of illness, the severity of lung injury did not significantly differ based on biomarker-determined smoking status. Cigarette smoke exposure was not significantly associated with death after adjusting for differences in age, alcohol use, comorbidities, and severity of illness.

CONCLUSIONS

In this first multicenter study of biomarker-determined cigarette smoke exposure in acute respiratory distress syndrome patients, we found that active cigarette smoke exposure was significantly more prevalent among acute respiratory distress syndrome patients compared to population averages. Despite their younger age, better overall health, and lower severity of illness, smokers by 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol had similar severity of lung injury as patients with undetectable 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol. These findings suggest that active cigarette smoking may increase susceptibility to acute respiratory distress syndrome in younger, healthier patients.

Correlates of secondhand tobacco smoke exposure among individuals with a history of substance use and/or psychiatric disorders participating in a tobacco treatment program in Vancouver, Canada

Individuals with substance use (SUD) and/or psychiatric disorders (PD) are disproportionately affected by tobacco use; yet, little is known about secondhand tobacco smoke (SHS) exposure in these populations. An analysis of existing data examined SHS exposure among 497 smokers in community clinics in Vancouver, Canada. Seventy-percent of the participants reported SHS exposure. In sex-stratified multivariate logistic regression analyses correlates of SHS exposure among women were not having a history of using evidence-based smoking cessation treatment and using a single substance (as compared to a polysubstance use history); whereas among men, a history of a respiratory illness and higher nicotine dependence were associated with SHS exposure. Despite limitations about the measures of SHS exposure used in the study, these findings suggest a need to further determine the risks associated with SHS exposure and tobacco use among individuals with SUD and/or PD within mental health and addictions treatment settings.

Levels and risks of particulate-bound PAHs in indoor air influenced by tobacco smoke: a field measurement

Considering tobacco smoke as one of the most health-relevant indoor sources, the aim of this work was to further understand its negative impacts on human health. The specific objectives of this work were to evaluate the levels of particulate-bound PAHs in smoking and non-smoking homes and to assess the risks associated with inhalation exposure to these compounds. The developed work concerned the application of the toxicity equivalency factors approach (including the estimation of the lifetime lung cancer risks, WHO) and the methodology established by USEPA (considering three different age categories) to 18 PAHs detected in inhalable (PM10) and fine (PM2.5) particles at two homes. The total concentrations of 18 PAHs (ΣPAHs) was 17.1 and 16.6 ng m(-3) in PM10 and PM2.5 at smoking home and 7.60 and 7.16 ng m(-3) in PM10 and PM2.5 at non-smoking one. Compounds with five and six rings composed the majority of the particulate PAHs content (i.e., 73 and 78 % of ΣPAHs at the smoking and non-smoking home, respectively). Target carcinogenic risks exceeded USEPA health-based guideline at smoking home for 2 different age categories. Estimated values of lifetime lung cancer risks largely exceeded (68-200 times) the health-based guideline levels at both homes thus demonstrating that long-term exposure to PAHs at the respective levels would eventually cause risk of developing cancer. The high determined values of cancer risks in the absence of smoking were probably caused by contribution of PAHs from outdoor sources.

Cigarette smoke toxins deposited on surfaces: implications for human health

Cigarette smoking remains a significant health threat for smokers and nonsmokers alike. Secondhand smoke (SHS) is intrinsically more toxic than directly inhaled smoke. Recently, a new threat has been discovered - Thirdhand smoke (THS) - the accumulation of SHS on surfaces that ages with time, becoming progressively more toxic. THS is a potential health threat to children, spouses of smokers and workers in environments where smoking is or has been allowed. The goal of this study is to investigate the effects of THS on liver, lung, skin healing, and behavior, using an animal model exposed to THS under conditions that mimic exposure of humans. THS-exposed mice show alterations in multiple organ systems and excrete levels of NNAL (a tobacco-specific carcinogen biomarker) similar to those found in children exposed to SHS (and consequently to THS). In liver, THS leads to increased lipid levels and non-alcoholic fatty liver disease, a precursor to cirrhosis and cancer and a potential contributor to cardiovascular disease. In lung, THS stimulates excess collagen production and high levels of inflammatory cytokines, suggesting propensity for fibrosis with implications for inflammation-induced diseases such as chronic obstructive pulmonary disease and asthma. In wounded skin, healing in THS-exposed mice has many characteristics of the poor healing of surgical incisions observed in human smokers. Lastly, behavioral tests show that THS-exposed mice become hyperactive. The latter data, combined with emerging associated behavioral problems in children exposed to SHS/THS, suggest that, with prolonged exposure, they may be at significant risk for developing more severe neurological disorders. These results provide a basis for studies on the toxic effects of THS in humans and inform potential regulatory policies to prevent involuntary exposure to THS.

Parental smoking during pregnancy and total and abdominal fat distribution in school-age children: the Generation R Study

OBJECTIVE

Fetal smoke exposure may influence growth and body composition later in life. We examined the associations of maternal and paternal smoking during pregnancy with total and abdominal fat distribution in school-age children.

METHODS

We performed a population-based prospective cohort study among 5243 children followed from early pregnancy onward in the Netherlands. Information about parental smoking was obtained by questionnaires during pregnancy. At the median age of 6.0 years (90% range: 5.7-7.4), we measured anthropometrics, total fat and android/gynoid fat ratio by dual-energy X-ray absorptiometry, and preperitoneal and subcutaneous abdominal fat were measured by ultrasound.

RESULTS

The associations of maternal smoking during pregnancy were only present among girls (P-value for sex interaction<0.05). Compared with girls from mothers who did not smoke during pregnancy, those from mothers who smoked during the first trimester only had a higher android/gynoid fat ratio (difference 0.23 (95% confidence interval (CI): 0.09-0.37) s.d. scores (SDS). Girls from mothers who continued smoking throughout pregnancy had a higher body mass index (difference: 0.24 (95% CI: 0.14-0.35) SDS), total fat mass (difference: 0.23 (95% CI: 0.14-0.33) SDS), android/gynoid fat ratio (difference: 0.34 (95% CI: 0.22-0.46) SDS), subcutaneous abdominal fat (difference: 0.22 (95% CI: 0.11-0.33) SDS) and preperitoneal abdominal fat (difference: 0.20 (95% CI: 0.08-0.31) SDS). Similar associations with body fat distribution outcomes were observed for paternal smoking during pregnancy. Both continued maternal and paternal smoking during pregnancy may be associated with an increased risk of childhood overweight. The corresponding odds ratios were 1.19 (95% CI: 0.98-1.46) and 1.32 (1.10-1.58), respectively.

CONCLUSIONS

Maternal and paternal smoking during pregnancy are associated with an adverse body and abdominal fat distribution and increased risk of overweight in children. Similar effects of maternal and paternal smoking suggest that direct intrauterine mechanisms and common family-based lifestyle-related factors explain the associations.

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.

Effect of tobacco smoking and smoking cessation on plasma lipoproteins and associated major cardiovascular risk factors: a narrative review

Cigarette smoking, active or passive, kills about 6 million people each year worldwide. Cardiovascular disease (CVD) is responsible for 40% of all smoking-related deaths, lung cancer accounts for 20% of all smoking-related deaths, and chronic obstructive pulmonary disease is related to another 20% of deaths. In this narrative review we consider the relationship between cigarette smoking and CVD. We discuss disease states and/or CVD risk factors related to smoking, such as dyslipidaemia, vascular inflammation, endothelial dysfunction, arterial stiffness, insulin resistance, type 2 diabetes mellitus (T2DM), chronic kidney disease (CKD), and non-alcoholic fatty liver disease (NAFLD) as well as their complex interrelations. Smoking cessation can correct abnormalities related to smoking; however, success rates are relatively low. In cases of inability to quit, measures to minimize the adverse effects of smoking specifically related to CVD should be taken. Smokers should receive best practice treatment, according to guidelines, as for non-smokers.

Abnormal sympathetic nerve activity in women exposed to cigarette smoke: a potential mechanism to explain increased cardiac risk

In women, cardiac deaths attributable to tobacco exposure have reached the same high levels as men. Normally, sympathetic nerve activity (SNA) fluctuates according to the menstrual phase, but in habitual smokers, SNA levels remain constant. Our purpose is to extend these observations to other groups of women exposed to tobacco smoke and to explore potential mechanisms. We hypothesize that women exposed to secondhand smoke, but not former smokers, have nonfluctuating SNA compared with never smokers, and that impaired baroreflex suppression of SNA, and/or heightened central SNA responses, underlie this nonfluctuating SNA. We also hypothesize that female smokers have impaired nocturnal blood pressure dipping, normally mediated by modulation of SNA. In 49 females (19 never, 12 current, 9 former, 9 passive smokers), SNA was recorded (microneurography) during high- and low-hormone ovarian phases at rest, during pharmacological baroreflex testing, and during the cold pressor test (CPT). Twenty-four hour blood pressure (BP) monitoring was performed. Current and passive smokers, but not former smokers, had a nonfluctuating pattern of SNA, unlike never smokers in whom SNA varied with the menstrual phase. Baroreflex control of SNA was significantly blunted in current smokers, independent of menstrual phase. In passive smokers, SNA response to CPT was markedly increased. Nondipping was unexpectedly high in all groups. SNA does not vary during the menstrual cycle in active and passive smokers, unlike never and former smokers. Baroreflex control of SNA is blunted in current smokers, whereas SNA response to CPT is heightened in passive smokers. Smoking cessation is associated with return of the altered SNA pattern to normal.

Secondhand smoke exposure and intermittent claudication: a Scotland-wide study of 4231 non-smokers

OBJECTIVE

Active smoking is an important risk factor for peripheral arterial disease. In contrast, published evidence on the association with secondhand smoke (SHS) is very limited. The aim of this study was to examine the association between SHS exposure and intermittent claudication (IC) among middle aged non-smokers.

DESIGN

Multivariate logistic regression analyses were used to adjust for potential confounders.

SETTING

The Scottish Health Survey, a pan-Scotland, representative survey of the general population.

PATIENTS

We conducted a cross-sectional study using the Scottish Health Surveys undertaken between 1998 and 2010. Inclusion was restricted to participants aged > 45 years.

MAIN OUTCOME MEASURES

Of the 4231 confirmed non-smokers (self-reported non-smokers with salivary cotinine concentrations < 15 ng/mL), 134 (3.2%) had IC based on the Edinburgh Claudication Questionnaire.

RESULTS

There was evidence of a dose relationship, whereby the risk of IC increased with increasing cotinine concentration. Following adjustment for potential confounders, participants with a cotinine concentration ≥ 2.7 ng/mL were still significantly more likely to have IC (OR 1.76, 95% CI 1.04 to 3.00; p = 0.036) compared with those with a cotinine concentration < 0.7 ng/mL. Among non-smokers, 5.6% (95% CI -0.8% to 11.7%) of cases of IC were attributable to cotinine concentrations ≥ 2.7 ng/mL and a further 3.6% (95% CI -6.6% to 12.8%) to cotinine concentrations of 0.7-2.6 ng/mL.

CONCLUSIONS

As with coronary heart disease and stroke, SHS exposure was independently associated with IC. Our findings add to the published evidence in support of protecting the general public from SHS exposure.

Impaired transcriptional response of the murine heart to cigarette smoke in the setting of high fat diet and obesity

Smoking and obesity are each well-established risk factors for cardiovascular heart disease, which together impose earlier onset and greater severity of disease. To identify early signaling events in the response of the heart to cigarette smoke exposure within the setting of obesity, we exposed normal weight and high fat diet-induced obese (DIO) C57BL/6 mice to repeated inhaled doses of mainstream (MS) or sidestream (SS) cigarette smoke administered over a two week period, monitoring effects on both cardiac and pulmonary transcriptomes. MS smoke (250 μg wet total particulate matter (WTPM)/L, 5 h/day) exposures elicited robust cellular and molecular inflammatory responses in the lung with 1466 differentially expressed pulmonary genes (p < 0.01) in normal weight animals and a much-attenuated response (463 genes) in the hearts of the same animals. In contrast, exposures to SS smoke (85 μg WTPM/L) with a CO concentration equivalent to that of MS smoke (~250 CO ppm) induced a weak pulmonary response (328 genes) but an extensive cardiac response (1590 genes). SS smoke and to a lesser extent MS smoke preferentially elicited hypoxia- and stress-responsive genes as well as genes predicting early changes of vascular smooth muscle and endothelium, precursors of cardiovascular disease. The most sensitive smoke-induced cardiac transcriptional changes of normal weight mice were largely absent in DIO mice after smoke exposure, while genes involved in fatty acid utilization were unaffected. At the same time, smoke exposure suppressed multiple proteome maintenance genes induced in the hearts of DIO mice. Together, these results underscore the sensitivity of the heart to SS smoke and reveal adaptive responses in healthy individuals that are absent in the setting of high fat diet and obesity.

[Statement of the Spanish Interdisciplinary Cardiovascular Prevention Committee (CEIPC for its Spanish acronym) on the 2012 European Cardiovascular Prevention Guidelines]

Based on the two main frameworks for evaluating scientific evidence (SEC and GRADE) European cardiovascular prevention guidelines recommend interventions across all life stages using a combination of population-based and high-risk strategies with diet as the cornerstone of prevention. The evaluation of cardiovascular risk (CVR) incorporates HDL levels and psychosocial factors, a very high risk category, and the concept of age-risk. They also recommend cognitive-behavioural methods (e.g., motivational interviewing, psychological interventions) led by health professionals and with the participation of the patient's family, to counterbalance psychosocial stress and reduce CVR through the institution of positive habits such as a healthy diet, physical activity, smoking cessation, and adherence to treatment. Additionally, public health interventions - such as smoking ban in public areas or the elimination of trans fatty acids from the food chain - are also essential. Other innovations include abandoning antiplatelet therapy in primary prevention and the recommendation of maintaining blood pressure within the 130-139/80-85mmHg range in diabetic patients and individuals with high CVR. Finally, due to the significant impact on patient progress and medical costs, special emphasis is given to the low therapeutic adherence levels observed. In sum, improving cardiovascular prevention requires a true partnership among the political class, public administrations, scientific and professional associations, health foundations, consumer associations, patients and their families. Such partnership would promote population-based and individual strategies by taking advantage of the broad spectrum of scientific evidence available, from clinical trials to observational studies and mathematical models to evaluate population-based interventions, including cost-effectiveness analyses.

Premature coronary heart disease and traditional risk factors-can we do better?

BACKGROUND

Traditional cardiovascular risk factors are strong predictors of an increased likelihood for premature CHD. Considering the benefits of risk factors᾿ management, it is imperative to find and treat them before looking for more unknown and weak risk factors.

OBJECTIVES

Limited information is available about the demographic and historical characteristics of the patients with premature Coronary Heart Disease (CHD) in IR Iran. The main objective of this study was to determine the prevalence of the traditional risk factors in these patients. Also, the researchers hypothesized that there are insufficient risk assessment and preventive intervention methods for the asymptomatic adult population.

METHODS

This study was conducted on 125 patients with premature CHD (age<50 years) who were admitted in two academic hospitals with acute coronary syndromes. The patients were accepted since they had a definite CHD on the basis of acute myocardial infarction (elevated cardiac enzymes) or documented CAD in coronary angiography.

RESULTS

The mean age of the study population was 42.50±5.65 (26 to 49 years). Among the patients,92 (73.6%) were male, 113 (90.4%) were married, 58 (46.4%) were smokers,19 (15.2%) were opium users, 97 (77.6%) had dyslipidemia, 44 (35.2%) had hypertension, and 33 (26.4%) had diabetes mellitus. In addition, family history was presented in 54 patients (43.2%). Among the study population, 120 patients (96%) had at least one of the traditional risk factors, including dyslipidemia, hypertension, diabetes mellitus, cigarette smoking, and family history of CHD. However, none of the dyslipidemic patients had controlled total cholesterol, LDL, HDL, and triglyceride. Also, none of the diabetic patients had hemoglobin A1C<7%. Among the 44 hypertensive patients, blood pressure of 15 ones (34%) was within the normal range. Besides, only 3 patients (2.4%) had regular physical activity (at least 30 minutes, three times a week).

CONCLUSIONS

Premature Coronary Heart Disease is a public health problem. However, there is lack of effective and intensive treatments of well-defined traditional risk factors and prevention methods for the majority of the patients experiencing premature CHD. In sum, there is still plenty of room for improvement of risk management in IR Iran.

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.

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.

Possible involvement of PPARγ-associated eNOS signaling activation in rosuvastatin-mediated prevention of nicotine-induced experimental vascular endothelial abnormalities

Nicotine exposure via cigarette smoking and tobacco chewing is associated with vascular complications. The present study investigated the effect of rosuvastatin in nicotine (2 mg/kg/day, i.p., 4 weeks)-induced vascular endothelial dysfunction (VED) in rats. The development of VED was assessed by employing isolated aortic ring preparation and estimating aortic and serum nitrite/nitrate concentration. Further, scanning electron microscopy and hematoxylin-eosin staining of thoracic aorta were performed to assess the vascular endothelial integrity. Moreover, oxidative stress was assessed by estimating aortic superoxide anion generation and serum thiobarbituric acid-reactive substances. The nicotine administration produced VED by markedly reducing acetylcholine-induced endothelium-dependent relaxation, impairing the integrity of vascular endothelium, decreasing aortic and serum nitrite/nitrate concentration, increasing oxidative stress, and inducing lipid alteration. However, treatment with rosuvastatin (10 mg/kg/day, i.p., 4 weeks) markedly attenuated nicotine-induced vascular endothelial abnormalities, oxidative stress, and lipid alteration. Interestingly, the co-administration of peroxisome proliferator-activated receptor γ (PPARγ) antagonist, GW9662 (1 mg/kg/day, i.p., 2 weeks) submaximally, significantly prevented rosuvastatin-induced improvement in vascular endothelial integrity, endothelium-dependent relaxation, and nitrite/nitrate concentration in rats administered nicotine. However, GW9662 co-administration did not affect rosuvastatin-associated vascular anti-oxidant and lipid-lowering effects. The incubation of aortic ring, isolated from rosuvastatin-treated nicotine-administered rats, with L-NAME (100 μM), an inhibitor of nitric oxide synthase (NOS), significantly attenuated rosuvastatin-induced improvement in acetylcholine-induced endothelium-dependent relaxation. Rosuvastatin prevents nicotine-induced vascular endothelial abnormalities by activating PPARγ and endothelial NOS signaling pathways. Moreover, the PPARγ-independent anti-oxidant and lipid-lowering effects of rosuvastatin might additionally play a role in the improvement of vascular endothelial function.

Students' attitude and smoking behaviour following the implementation of a university smoke-free policy: a cross-sectional study

OBJECTIVE

In view of the high-smoking rate among university students in Lebanon and the known adverse effects of second-hand smoking, the American University of Beirut (AUB) decided to implement a non-smoking policy on campus. This study sought to examine the students' compliance and attitudes following the ban.

DESIGN

Cross-sectional study.

SETTING

A private university in Lebanon.

PARTICIPANTS

545 randomly selected students were approached. A stratified cluster sample of classes offered in the spring semester of the 2008/2009 academic year was selected. Students completed a self-administered paper and pencil survey during class time.

PRIMARY AND SECONDARY OUTCOME MEASURES

The main outcomes were compliance with and attitudes towards the ban. Other secondary outcomes were the perception of barriers to implementation of the ban and attitudes towards tobacco control in general.

RESULTS

535 students participated in the study. Smokers were generally compliant with the ban (72.7%) and for some (20%) it led to a decrease in their smoking. Students' attitude towards the ban and the enforcement of a non-smoking policy in public places across Lebanon varied according to their smoking status whereby non-smokers possessed a more favourable attitude and strongly supported such policies compared with smokers; overall, the largest proportions of students were satisfied to a large extent with the ban and considered it justified (58.6% and 57.2%, respectively). While much smaller percentages reported that the ban would help in reducing smoking to a large extent (16.7%) or it would help smokers quit (7.4%). Perceived barriers to implementation of the non-smoking policy in AUB included the lack of compliance with and strict enforcement of the policy as well as the small number and crowdedness of the smoking areas.

CONCLUSIONS

An education campaign, smoking cessation services and strict enforcement of the policy might be necessary to boost its effect in further reducing students' cigarette use.

Burden of household environmental tobacco smoke on medical expenditure for Japanese women: a population-based cohort study

BACKGROUND

The economic consequences of environmental tobacco smoke (ETS) have been simulated using models. We examined the individual-level association between ETS exposure and medical costs among Japanese nonsmoking women.

METHODS

This population-based cohort study enrolled women aged 40 to 79 years living in a rural community. ETS exposure in homes at baseline was assessed with a self-administered questionnaire. We then collected health insurance claims data on direct medical expenditures from 1995 through 2007. Using generalized linear models with interaction between ETS exposure level and age stratum, average total monthly expenditure (inpatient plus outpatient care) per capita for nonsmoking women highly exposed and moderately exposed to ETS were compared with expenditures for unexposed women. We performed separate analyses for survivors and nonsurvivors.

RESULTS

We analyzed data from 4870 women. After adjustment for potential confounding factors, survivors aged 70 to 79 who were highly exposed to ETS incurred higher expenditures than those who were not exposed. We found no significant difference in expenditures between moderately exposed and unexposed women. Total expenditures were not significantly associated with ETS exposure among survivors aged 40 to 69 or nonsurvivors of any age stratum.

CONCLUSIONS

We calculated individual-level excess medical expenditures attributable to household exposure to ETS among surviving older women. The findings provide direct evidence of the economic burden of ETS, which is helpful for policymakers who seek to achieve the economically attractive goal of eliminating ETS.

The effect of cigarette smoke extract on thrombomodulin-thrombin binding: an atomic force microscopy study

Cigarette smoking is a well-known risk factor for cardiovascular disease. Smoking can cause vascular endothelial dysfunction and consequently trigger haemostatic activation and thrombosis. However, the mechanism of how smoking promotes thrombosis is not fully understood. Thrombosis is associated with the imbalance of the coagulant system due to endothelial dysfunction. As a vital anticoagulation cofactor, thrombomodulin (TM) located on the endothelial cell surface is able to regulate intravascular coagulation by binding to thrombin, and the binding results in thrombosis inhibition. This work focused on the effects of cigarette smoke extract (CSE) on TM-thrombin binding by atomic force microscopy (AFM) based single-molecule force spectroscopy. The results from both in vitro and live-cell experiments indicated that CSE could notably reduce the binding probability of TM and thrombin. This study provided a new approach and new evidence for studying the mechanism of thrombosis triggered by cigarette smoking.

Atherogenic and pulmonary responses of ApoE- and LDL receptor-deficient mice to sidestream cigarette smoke

Plasma lipoproteins play important roles in the development and progression of atherosclerosis. Two widely used mouse models of experimental atherosclerosis, apolipoprotein E-deficient (ApoE -/-) and LDL receptor-deficient (LDLr -/-) mice, have major differences in lipoprotein characteristics. These include differences in lipoprotein cholesterol distribution, lipoprotein compositions, apoliporoteins distribution, and susceptibility to oxidation. In the present study, we compared pulmonary and cardiovascular responses of ApoE -/- and LDLr -/- mice to sidestream cigarette smoke (SSCS) exposure to determine if strain differences influence their predisposition to SSCS-mediated promotion of atherosclerosis. Female ApoE -/- and LDLr -/- mice were maintained on a saturated fat enriched diet and exposed to SSCS in whole body exposure chambers for 15 weeks (4h/day, 5 days/week). At terminations, the levels of pulmonary injury markers in bronchoalveolar lavage (BAL) fluids from 6 mice per group and atherosclerotic lesion formation in 14 mice per group were analyzed. Total BAL cells and polymorphonuclear leukocytes were not significantly altered by SSCS exposure in both mouse models. Total protein, LDH, and cytokine concentrations in cell-free BAL fluids were also not significantly affected by chronic SSCS exposure in either mouse strain. SSCS significantly reduced surfactant protein D levels in both strains to a similar extent. However, SSCS exposure increased significantly the percent atherosclerotic lesion areas covering aortic intimal surfaces of ApoE -/- (control-25.3±1.52 vs. SSCS-31.9±2.02, p=0.012) as well as in LDLr -/- (control-30.97±1.1 vs. SSCS-36.61±1.7, p=0.028) mice. In contrast, the serum cholesterol concentrations of SSCS-exposed ApoE -/- mice were similar to that of controls (control-1255±85 vs. SSCS-1190±61mg/dl, p=0.552) but increased significantly in SSCS-exposed LDLr -/- mice (control-998±114 vs. SSCS-1577±142mg/dl, p=0.008). These results showing different effects of identical SSCS exposure on plasma cholesterol concentrations in these two mouse models suggest a role of multiple mechanisms in SSCS-induced atherosclerosis.