Passive smoking and risk of coronary heart disease and stroke: prospective study with cotinine measurement

Very low nicotine content cigarettes and potential consequences on cardiovascular disease

Cigarette smoking remains highly prevalent in the U.S. and contributes significantly to cardiovascular disease (CVD). Tobacco control policies, including product regulation, can reduce smoking-related harm. One approach being considered in the U.S. is for the FDA to set a low nicotine standard for cigarettes. Such a standard could result in multiple beneficial outcomes including reduced cardiovascular toxicity related to nicotine, reduced smoking intensity in current smokers, increased cessation rates, decreased development of smoking dependence in youth, and decreased passive smoke exposure. Consequently, CVD risk in the U.S. could be dramatically improved by nicotine reduction in cigarettes. Possible pathways linking nicotine reduction in cigarettes to decreased CVD risk are discussed, while potential unintended consequences that could offset expected gains are also presented. Gaps in the literature, including limited data on CVD biomarkers and long-term CVD outcomes following the use of very low nicotine cigarettes, are discussed to highlight areas for new research.

Second hand smoke and cardiovascular disease in Low and Middle Income Countries: a case for action

Second hand tobacco smoke (SHS) is an environmental toxin and an established cause of cardiovascular disease in nonsmokers. Smoke free laws reduce SHS and its downstream cardiovascular disease, but until recently evidence to support smoke free law implementation in low and middle income country settings was limited. In 14 low and middle income nations surveyed by the Global Adult Tobacco Survey active smoking prevalence in adults (≥15 years old) was universally higher in males (range 21.6-60.2%) compared with females (0.5-24.4%), and the highest burden of SHS exposure was in women (strong positive association between male/female active smoking ratio and female SHS exposure prevalence). A systematic review was conducted of MEDLINE-indexed studies of self-reported SHS exposure and cardiovascular harms in low or middle income nations. Eight papers reported the association of SHS with ischemic heart disease and four reported the association of SHS with stroke. For all the studies, and almost all sources of SHS surveyed, a strong positive association between SHS and ischemic heart disease (main relative odds ratio range 1.17-2.36) and SHS and stroke (odds ratio or hazard ratio 1.41-1.49). Prevalence of SHS exposure is high in low and middle income nations, especially among women. Epidemiologic evidence supports the conclusion that SHS harms are the same across low, middle and high income nations. Governments have an obligation to protect citizens from SHS exposure, enforcing smoke-free legislation and providing public education about SHS harms.

Exposure to environmental tobacco smoke and absence from work in women in Nis, Serbia

Exposure to environmental tobacco smoke leads to very serious health effects, especially on the respiratory system. The objective of this paper was to estimate the influence of passive smoking on absence from work because of respiratory problems in women. The study sample consisted of 497 women aged 40-56 who live in an area with identical outdoor air pollution. Environmental tobacco smoke exposure was recorded in 346 women. Data about respiratory symptoms in women were entered into a structured questionnaire. Statistics tests showed no significant difference of living conditions, keeping pets, hereditary predisposition among women. The occurrence of congested nose (OR = 3.47; 95% Cl = 1.38-9.01), nasal secretion (OR = 3.48; 95% Cl = 1.38-9.02) and sinusitis (OR = 2.88; 95% Cl = 1.22-6.89) was significantly higher in women who were exposed to environmental tobacco smoke. Primary health care need for respiratory symptoms due to the effect of passive smoking is higher in the exposed women. Passive smoking can be a risk factor for the appearance of respiratory symptoms and illness in women that causes absence from work.

Parental Smoking in Childhood and Brachial Artery Flow-Mediated Dilatation in Young Adults

Objective—

Passive smoking has been associated with increased cardiovascular morbidity. The present study aimed to examine the long-term effects of childhood exposure to tobacco smoke on endothelium-dependent vasodilation in adults.

Methods and Results—

The analyses were based on 2171 participants in the population-based Cardiovascular Risk in Young Finns (N=2067) and Childhood Determinants of Adult Health (N=104) studies who had measures of conventional risk factors (lipids, blood pressure, adiposity, socioeconomic status) and self-reported parental smoking status when aged 3 to 18 years at baseline. They were re-examined 19 to 27 years later when aged 28 to 45 years. Brachial artery flow-mediated dilatation was measured at follow-up with ultrasound. In analyses adjusting for age, sex, and childhood risk factors, flow-mediated dilatation was reduced among participants who had parents that smoked in youth compared to those whose parents did not smoke (Young Finns: 9.2±0.1% (mean±SEM) versus 8.6±0.1%, P =0.001; Childhood Determinants of Adult Health: 7.4±0.6% versus 4.9±0.9%, P =0.04). These effects remained after adjustment for adult risk factors including own smoking status (Young Finns, P =0.003; Childhood Determinants of Adult Health, P =0.03).

Conclusion—

Parental smoking in youth is associated with reduced flow-mediated dilatation in young adulthood measured over 20 years later. These findings suggest that passive exposure to cigarette smoke among children might cause irreversible impairment in endothelium-dependent vasodilation.

Did smokefree legislation in England reduce exposure to secondhand smoke among nonsmoking adults? Cotinine analysis from the Health Survey for England

BACKGROUND

On 1 July 2007, smokefree legislation was implemented in England, which made virtually all enclosed public places and workplaces smokefree.

OBJECTIVES

We examined trends in and predictors of secondhand smoke exposure among nonsmoking adults to determine whether exposure changed after the introduction of smokefree legislation and whether these changes varied by socioeconomic status (SES) and by household smoking status.

METHODS

We analyzed salivary cotinine data from the Health Survey for England that were collected in 7 of 11 annual surveys undertaken between 1998 and 2008. We conducted multivariate regression analyses to examine secondhand smoke exposure as measured by the proportion of nonsmokers with undetectable levels of cotinine and by geometric mean cotinine.

RESULTS

Secondhand smoke exposure was higher among those exposed at home and among lower-SES groups. Exposure declined markedly from 1998 to 2008 (the proportion of participants with undetectable cotinine was 2.9 times higher in the last 6 months of 2008 compared with the first 6 months of 1998 and geometric mean cotinine declined by 80%). We observed a significant fall in exposure after legislation was introduced--the odds of having undetectable cotinine were 1.5 times higher [95% confidence interval (CI): 1.3, 1.8] and geometric mean cotinine fell by 27% (95% CI: 17%, 36%) after adjusting for the prelegislative trend and potential confounders. Significant reductions were not, however, seen in those living in lower-social class households or homes where smoking occurs inside on most days.

CONCLUSIONS

We found that the impact of England's smokefree legislation on secondhand smoke exposure was above and beyond the underlying long-term decline in secondhand smoke exposure and demonstrates the positive effect of the legislation. Nevertheless, some population subgroups appear not to have benefitted significantly from the legislation. This finding suggests that these groups should receive more support to reduce their exposure.

Clean Indoor Air Acts reduce the burden of adverse cardiovascular outcomes

OBJECTIVES

Second-hand smoke is associated with an increased risk of adverse health outcomes, such as acute myocardial infarction (AMI) and coronary heart disease (CHD). At present, 38 US states/territories have enacted Clean Indoor Air Acts (CIAAs). The purpose of the current study was to compare the prevalence of self-reported health outcomes on a state/territory-wide level 1 year prior to CIAA implementation and at least 1 year after CIAA implementation for each respective state/territory.

STUDY DESIGN

Pre-test, post-test study.

METHODS

Seventeen states/territories with pre- and post-CIAA data were included in the current study. All data (AMI, CHD/angina, former and current smoker rates) were collected from the Behavioral Risk Factor Surveillance System (BRFSS) in the year prior to each state/territory's respective CIAA implementation (baseline) and 2009 (most recent year with BRFSS data).

RESULTS

Between baseline and 2009, 10 states/territories (58.8%) had a significant decrease in the prevalence of CHD/angina or AMI, 11 states/territories (64.7%) had a significant decrease in the prevalence of current smokers, and three states/territories (17.7%) had a significant decrease in the prevalence of both current and former smokers. Six states/territories (35.3%) had a significant increase in the prevalence of former smokers.

CONCLUSIONS

State/territory-wide CIAAs are beneficial in reducing adverse cardiovascular health outcomes in the short term. The prevalence of AMI, CHD/angina, and former and current smokers decreased significantly following CIAA implementation. The current study adds further support for the passage and implementation of CIAAs on a state/territory-wide level. However, further studies need to be conducted to assess the long-term outcomes of CIAAs.

Smoke-free laws, gender, and reduction in hospitalizations for acute myocardial infarction

OBJECTIVE

We examined gender differences in the incidence of acute myocardial infarction (AMI) after the passage of a smoke-free law in Lexington, Kentucky. The initial legislation had exemptions not covering manufacturing facilities and government buildings, which may have put men at greater risk for AMI.

METHODS

We examined the effect of Lexington's smoke-free public places law on hospitalizations for AMI (i.e., heart attack) among men and women 40 months prior to and 32 months after enactment of the law. We used the statewide administrative database (Comp Data) for all hospital billing records for the four health-care systems in Lexington-Fayette County. Cases were included in the analysis if (1) the patient was $35 years of age; (2) the patient had a primary discharge diagnosis of AMI, with an International Classification of Diseases, Ninth Revision code in the range of 410.00 to 410.99; and (3) the date of service was between January 1, 2001, and December 31, 2006.

RESULTS

Among women, AMI hospitalizations declined 23% after the law took effect. The rate of AMI events among men did not change significantly. There was an overrepresentation of women in the hospitality industry and a disproportionate number of men working in manufacturing facilities and government worksites not mandated by the law.

CONCLUSIONS

We found gender differences in the reduction of AMI hospitalizations following implementation of a smoke-free law that covered only some sectors of the workforce. Enacting smoke-free laws that cover all places of employment and strengthening existing partial laws may extend protection against AMIs to female and male workers.

In vitro assessment of tobacco smoke toxicity at the BBB: do antioxidant supplements have a protective role?

BACKGROUND

Tobacco smoke (TS) contains highly reactive oxygen species (such as hydrogen peroxide, peroxynitrite, etc), which cause oxidative damage in vascular tissue and may exacerbate inflammatory events leading to the blood-brain barrier damage (BBBD) which accompanies the development of a variety of neurological disorders. Smokers often have elevated leukocyte counts (primarily neutrophils and monocytes), and significant decreases in plasma alpha-tocopherol (vitamin E) and ascorbic acid (vitamin C) levels due to increased anti-oxidative mobilization in response to oxidative stress evoked by TS. For this purpose, using static culture systems and a well-established dynamic in vitro BBB model (DIV-BBB) we tested the hypothesis that antioxidant vitamin supplementation (E and/or C) can protect the BBB during exposure to whole soluble TS.

RESULTS

TS exacerbates inflammatory events and leads to endothelial overexpression of vascular adhesion molecules (VCAM-1, P-selectin and E-selectin), release of pro-inflammatory cytokines (TNF-α and IL-6) and nitric oxide (NO), release and activation of matrix metalloproteinases (MMP-2 and MMP-9), monocytic maturation into macrophages, and adhesion to the vascular endothelium. Furthermore, TS altered the normal glucose metabolic behaviour of in vitro BBB capillaries and caused a period of transient anaerobic respiration to meet the cellular bioenergetic demand. Pre-treatment with antioxidant vitamins (C and/or E) effectively reduced the pro-inflammatory activity associated with TS, protecting the viability and functions of the BBB.

CONCLUSION

Our results have shown that loss of endothelial viability as well as BBB function and integrity caused by TS exposure can be prevented or at least reduced by normal physiologic concentrations of antioxidant vitamins in vitro.

Associations between respiratory illnesses and secondhand smoke exposure in flight attendants: A cross-sectional analysis of the Flight Attendant Medical Research Institute Survey

ABSTRACT: BACKGROUND: Secondhand tobacco smoke (SHS) is associated with increased risk of respiratory illness, cancer, and cardiovascular disease. Prior to smoking bans on airlines in the late 1980s, flight attendants were exposed to a significant amount of SHS. In the present study, we examine associations between flight attendant SHS exposure and development of respiratory illnesses and cardiovascular disease. METHODS: Between December 2006 and October 2010, three hundred sixty-two flight attendants completed an online questionnaire with information regarding experience as a flight attendant, medical history, smoking history, and SHS exposure. Rates of illnesses in flight attendants were compared with an age and smoking history matched population sample from NHANES 2005-2006. Logistic regression analysis was used to examine the association of reported medical conditions and pre-ban years of exposure. RESULTS: Compared with the sample from NHANES 2005-2006, flight attendants had increased prevalence of chronic bronchitis (11.7% vs. 7.2%, p < 0.05), emphysema/COPD (3.2% vs. 0.9%, p < 0.03), and sinus problems (31.5% vs. 20.9%, p < 0.002), despite a lower prevalence of medical illnesses including high blood pressure, diabetes, high cholesterol, heart failure, cancer, and thyroid disease. Amongst flight attendants who reported never smoking over their lifetimes, there was not a significant association between years of service as a flight attendant in the pre-smoking ban era and illnesses. However, in this same group, there was a significantly increased risk of daily symptoms (vs. no symptoms) of nasal congestion, throat, or eye irritation per 10-year increase of years of service as a flight attendant prior to the smoking ban (OR 2.14, 95% CI 1.41 - 3.24). CONCLUSIONS: Flight attendants experience increased rates of respiratory illnesses compared to a population sample. The frequency of symptoms of nasal congestion, throat or eye irritation is associated with occupational SHS exposure in the pre-smoking ban era.

Interactions between smoking, pulmonary surfactant protein B, and atherosclerosis in the general population: the Dallas Heart Study

OBJECTIVE

Pulmonary surfactant protein B (SP-B), an alveolar protein normally detectable at only very low concentrations in blood, circulates at higher levels among smokers and those with alveolar injury and inflammation. We hypothesized that SP-B may serve as a marker of the vascular effects of smoking and would thus be associated with subclinical measures of atherosclerosis.

METHODS AND RESULTS

Plasma levels of SP-B were measured in 3294 subjects, ages 30 to 65, enrolled in the Dallas Heart Study, a probability-based population sample of Dallas County adults. Coronary artery calcium (CAC) was measured by computed tomography and abdominal aortic plaque (AP) by magnetic resonance imaging. The cohort comprised 29% current and 17% former smokers. The overall prevalence of CAC was 22%, and that of AP was 39%. Median SP-B levels were 5-fold higher among current versus never smokers (P<0.0001) and were significantly correlated with estimated pack-years smoked (Spearman ρ=0.35, P<0.0001). Increasing levels of SP-B also associated with other traditional cardiac risk factors and higher levels of inflammatory biomarkers. In univariable analyses, increasing SP-B quartiles associated with higher prevalence of both CAC and AP (P(trend)<0.0001 for each). In multivariable analyses adjusting for traditional cardiovascular risk factors, SP-B remained associated with AP (OR 1.87 for the 4th versus 1st quartiles, 95% confidence interval 1.39 to 2.51; P<0.0001) but not CAC. An interaction was observed between SP-B, smoking status, and AP (P(interaction)=0.01), such that SP-B associated with AP in current smokers (adjusted OR 2.15 for the 4th versus 1st quartile, 95% confidence interval 1.26 to 3.67; P=0.005) but not in former or never smokers.

CONCLUSIONS

Circulating levels of SP-B increase with greater smoking burden and independently associate with abdominal AP among current smokers. Our findings support further investigation of the role of SP-B as a marker of the vascular effects of smoking.

Fine particle air pollution and secondhand smoke exposures and risks inside 66 US casinos

Smoking bans often exempt casinos, exposing occupants to fine particles (PM(2.5)) from secondhand smoke. We quantified the relative contributions to PM(2.5) from both secondhand smoke and infiltrating outdoor sources in US casinos. We measured real-time PM(2.5), particulate polycyclic aromatic hydrocarbons (PPAH), and carbon dioxide (CO(2)) (as an index of ventilation rate) inside and outside 8 casinos in Reno, Nevada. We combined these data with data from previous studies, yielding a total of 66 US casinos with smoking in California, Delaware, Nevada, New Jersey, and Pennsylvania, developing PM(2.5) frequency distributions, with 3 nonsmoking casinos for comparison. Geometric means for PM(2.5) were 53.8 μg/m(3) (range 18.5-205 μg/m(3)) inside smoking casinos, 4.3 μg/m(3) (range 0.26-29.7 μg/m(3)) outside those casinos, and 3.1 μg/m(3) (range 0.6-9 μg/m(3)) inside 3 nonsmoking casinos. In a subset of 21 Reno and Las Vegas smoking casinos, PM(2.5) in gaming areas averaged 45.2 μg/m(3) (95% CI, 37.7-52.7 μg/m(3)); adjacent nonsmoking casino restaurants averaged 27.2 μg/m(3) (95% CI, 17.5-36.9 μg/m(3)), while PM(2.5) outside the casinos averaged 3.9 μg/m(3) (95% CI, 2.5-5.3 μg/m(3)). For a subset of 10 Nevada and Pennsylvania smoking casinos, incremental (indoor-outdoor) PM(2.5) was correlated with incremental PPAH (R(2)=0.79), with ventilation rate-adjusted smoker density (R(2)=0.73), and with smoker density (R(2)=0.60), but not with ventilation rates (R(2)=0.15). PPAH levels in 8 smoking casinos in 3 states averaged 4 times outdoors. The nonsmoking casinos' PM(2.5) (n=3) did not differ from outdoor levels, nor did their PPAH (n=2). Incremental PM(2.5) from secondhand smoke in approximately half the smoking casinos exceeded a level known to produce cardiovascular morbidity in nonsmokers after less than 2h of exposure, posing acute health risks to patrons and workers. Casino ventilation and air cleaning practices failed to control secondhand smoke PM(2.5). Drifting PM(2.5) from secondhand smoke contaminated unseparated nonsmoking areas. Smoke-free casinos reduced PM(2.5) to the same low levels found outdoors.

The Magnitude of Mortality from Ischemic Heart Disease Attributed to Occupational Factors in Korea - Attributable Fraction Estimation Using Meta-analysis

Objectives

Ischemic heart disease (IHD) is a major cause of death in Korea and known to result from several occupational factors. This study attempted to estimate the current magnitude of IHD mortality due to occupational factors in Korea.

Methods

After selecting occupational risk factors by literature investigation, we calculated attributable fractions (AFs) from relative risks and exposure data for each factor. Relative risks were estimated using meta-analysis based on published research. Exposure data were collected from the 2006 Survey of Korean Working Conditions. Finally, we estimated 2006 occupation-related IHD mortality.

Results

For the factors considered, we estimated the following relative risks: noise 1.06, environmental tobacco smoke 1.19 (men) and 1.22 (women), shift work 1.12, and low job control 1.15 (men) and 1.08 (women). Combined AFs of those factors in the IHD were estimated at 9.29% (0.3-18.51%) in men and 5.78% (-7.05-19.15%) in women. Based on these fractions, Korea's 2006 death toll from occupational IHD between the age of 15 and 69 was calculated at 353 in men (total 3,804) and 72 in women (total 1,246).

Conclusion

We estimated occupational IHD mortality of Korea with updated data and more relevant evidence. Despite the efforts to obtain reliable estimates, there were many assumptions and limitations that must be overcome. Future research based on more precise design and reliable evidence is required for more accurate estimates.

The effect of secondhand smoke exposure on markers of elastin degradation

BACKGROUND

Tobacco smoke is a major risk factor in the development of COPD. Secondhand smoke (SHS) exposure is a known risk factor in asthma, bronchitis, and coronary artery disease. Elastin is a recognized target for injury in COPD, and the amino acids desmosine and isodesmosine (D/I), which are specific for elastin degradation, are elevated in COPD. This study determined whether exposure to SHS affects elastin degradation in asymptomatic individuals.

METHODS

Two cohorts of asymptomatic individuals without evidence of respiratory or circulatory disease, exposed to SHS, were studied. Both cohorts comprised normal nonsmokers, active smokers, and those exposed to SHS. D/I were measured in plasma and quantified by high-performance liquid chromatography and tandem mass spectrometry by published methods. Plasma cotinine, a metabolite of nicotine, was also measured.

RESULTS

In each cohort, the levels of D/I in plasma were statistically significantly higher in secondhand-smoke-exposed subjects than in the normal nonexposed subjects. Smokers had the highest levels of D/I but their levels were not statistically significantly higher than those of the secondhand-smoke-exposed. Cotinine levels were elevated in secondhand-smoke-exposed subjects and active smokers but not in most nonsmoking control subjects.

CONCLUSIONS

Results indicate a tissue matrix effect of degradation of body elastin from SHS exposure and possible lung structure injury, which may result in COPD. Long-term studies of individuals exposed to SHS for the development of COPD are warranted.

Smoking, secondhand smoke, and cotinine levels in a subset of EPIC cohort

BACKGROUND

Several countries are discussing new legislation regarding the ban on smoking in public places, based on the growing evidence of the hazards of secondhand smoke (SHS) exposure. The objective of the present study is to quantitatively assess the relationship between smoking, SHS, and serum cotinine levels in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort.

METHODS

From a study on lung cancer in the EPIC cohort, questionnaire information on smoking was collected at enrolment, and cotinine was measured in serum. Three statistical models were applied by using samples available in a cross-section design: (i) cotinine levels by categories combining smoking and SHS (n = 859); (ii) the effect of hours of passive smoking exposure in nonsmokers only (n = 107); (iii) the effect of the number of cigarettes consumed per day in current smokers only (n = 832). All models were adjusted for country, sex, age, and body mass index.

RESULTS

Among nonsmokers, passive smokers presented significant differences in cotinine compared with nonexposed, with a marked (but not significant) difference among former-smokers. A one hour per day increment of SHS gave rise to a significant 2.58 nmol/L (0.45 ng/mL) increase in mean serum cotinine (P < 0.001). In current smokers, a one cigarette per day increment gave rise to a significant 22.44 nmol/L (3.95 ng/mL) increase in cotinine mean (P < 0.001).

CONCLUSIONS

There is clear evidence that not only tobacco smoking but also involuntary exposure increases cotinine levels.

IMPACT

This study strengthens the evidence for the benefits of a smoking ban in public places.

Comparison of urine cotinine and the tobacco-specific nitrosamine metabolite 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) and their ratio to discriminate active from passive smoking

OBJECTIVES

Cotinine is the most widely used biomarker to distinguish active versus passive smoking. However, there is an overlap in cotinine levels when comparing light or occasional smokers versus heavily exposed passive smokers. 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) is a tobacco-specific nitrosamine measurable in urine with a much longer half-life than cotinine. The aim of the study was to determine optimal cutoff points to discriminate active versus passive smokers and to compare sensitivity and specificity for the use of cotinine, NNAL, and the ratio of the NNAL/cotinine in urine.

METHODS

Cotinine and NNAL were measured in urine of 373 active smokers and 228 passive smokers.

RESULTS

Geometric mean cotinine levels were 2.03 ng/ml (interquartile interval: 0.43-8.60) and 1,043 ng/ml (658-2,251) and NNAL levels were 5.80 pg/ml (2.28-15.4) and 165 pg/ml (90.8-360) pg/ml in passive and active smokers, respectively. NNAL/cotinine ratio in urine was significantly higher for passive smokers when compared with active smokers (2.85 vs. 0.16, p < .01). The receiver operating characteristics analysis determined optimal cutoff points to discriminate passive versus active smokers: 31.5 ng/ml for cotinine (sensitivity: 97.1% and specificity: 93.9%), 47.3 pg/ml for NNAL (87.4% and 96.5%), and 0.74 x 10⁻³ for NNAL/cotinine ratio (97.3% and 87.3%).

CONCLUSIONS

Both urine cotinine and NNAL are sensitive and specific biomarkers for discriminating the source of tobacco smoke exposure. Cotinine is the best overall discriminator when biomarkers are measured while a person has ongoing exposure to tobacco smoke. NNAL because of its long half-life would be particularly useful when there is a delay between exposure and biomarker measurement. The NNAL/cotinine ratio provides similar sensitivity but poorer specificity at discriminating passive versus active smokers when compared with NNAL alone.

Guidelines for the primary prevention of stroke: a guideline for healthcare professionals from the American Heart Association/American Stroke Association

BACKGROUND AND PURPOSE

This guideline provides an overview of the evidence on established and emerging risk factors for stroke to provide evidence-based recommendations for the reduction of risk of a first stroke.

METHODS

Writing group members were nominated by the committee chair on the basis of their previous work in relevant topic areas and were approved by the American Heart Association (AHA) Stroke Council Scientific Statement Oversight Committee and the AHA Manuscript Oversight Committee. The writing group used systematic literature reviews (covering the time since the last review was published in 2006 up to April 2009), reference to previously published guidelines, personal files, and expert opinion to summarize existing evidence, indicate gaps in current knowledge, and when appropriate, formulate recommendations using standard AHA criteria (Tables 1 and 2). All members of the writing group had the opportunity to comment on the recommendations and approved the final version of this document. The guideline underwent extensive peer review by the Stroke Council leadership and the AHA scientific statements oversight committees before consideration and approval by the AHA Science Advisory and Coordinating Committee.

RESULTS

Schemes for assessing a person's risk of a first stroke were evaluated. Risk factors or risk markers for a first stroke were classified according to potential for modification (nonmodifiable, modifiable, or potentially modifiable) and strength of evidence (well documented or less well documented). Nonmodifiable risk factors include age, sex, low birth weight, race/ethnicity, and genetic predisposition. Well-documented and modifiable risk factors include hypertension, exposure to cigarette smoke, diabetes, atrial fibrillation and certain other cardiac conditions, dyslipidemia, carotid artery stenosis, sickle cell disease, postmenopausal hormone therapy, poor diet, physical inactivity, and obesity and body fat distribution. Less well-documented or potentially modifiable risk factors include the metabolic syndrome, excessive alcohol consumption, drug abuse, use of oral contraceptives, sleep-disordered breathing, migraine, hyperhomocysteinemia, elevated lipoprotein(a), hypercoagulability, inflammation, and infection. Data on the use of aspirin for primary stroke prevention are reviewed.

CONCLUSIONS

Extensive evidence identifies a variety of specific factors that increase the risk of a first stroke and that provide strategies for reducing that risk.

Passive smoking in never-smokers is associated with increased plasma homocysteine levels

Smoking is associated with increased plasma homocysteine levels, and both are associated with an increased risk of cardiovascular disease. However, little information is available on the effects of passive smoking on the level of homocysteine in nonsmokers. We analyzed the data of self-reported never-smokers (aged > or = 20 years, n = 3,232), who were from the Third National Health and Nutrition Examination Survey. We quantified the passive nicotine exposure by dividing the never-smokers into quartiles as based on the serum cotinine values. Multiple linear and logistic regression models were used to determine any independent relationships between serum cotinine concentration and levels of homocysteine, vitamin B12, and folate. An elevated homocysteine level was defined as a concentration greater than the 80th percentile. A reduced folate or vitamin B12 level was defined as a concentration less than the 20th percentile.After adjusting for age, gender, body mass index, race, folate and vitamin B12 levels, increased cotinine levels (quartile III and IV) were found to be associated with hyperhomocysteinemia. There was a strong nonlinear increase in the serum homocysteine levels across the quartiles of cotinine. Multivariate analysis showed that age, male gender, non-Caucasian, low levels of folate and vitamin B12, and increased serum cotinine (quartile II-IV) were independently associated with elevated homocysteine levels. In conclusion, these findings indicate that passive smoke exposure in never-smokers is positively and independently associated with plasma homocysteine levels in a dose-dependent manner. These findings may help further determine the link between passive smoking and cardiovascular events.

Cotinine-assessed second-hand smoke exposure and risk of cardiovascular disease in older adults

Objectives

To examine whether second-hand smoke (SHS) exposure measured by serum cotinine is associated with increased coronary heart disease (CHD) and stroke risk among contemporary older British adults.

Design

Prospective population-based study with self-reported medical history and health behaviours. Fasting blood samples were analysed for serum cotinine and cardiovascular disease (CVD) risk markers.

Setting

Primary care centres in 25 British towns in 1998–2001.

Patients

8512 60–79-year-old men and women selected from primary care registers.

Main outcome measures

Fatal and non-fatal myocardial infarction (MI; n=445) and stroke (n=386) during median 7.8-year follow-up.

Main exposure

Observational study of serum cotinine assayed from fasting blood sample using liquid chromatography tandem mass spectrometry method, and self-reported smoking history.

Results

Among 5374 non-smokers without pre-existing CVD, geometric mean cotinine was 0.15 ng/ml (IQR 0.05–0.30). Compared with non-smokers with cotinine ≤0.05 ng/ml, higher cotinine levels (0.06–0.19, 0.2–0.7 and 0.71–15.0 ng/ml) showed little association with MI; adjusted HRs were 0.92 (95% CI 0.63 to 1.35), 1.07 (0.73 to 1.55) and 1.09 (0.69 to 1.72), p(trend)=0.69. Equivalent HRs for stroke were 0.82 (0.55 to 1.23), 0.74 (0.48 to 1.13) and 0.69 (0.41 to 1.17), p(trend)=0.065. The adjustment for sociodemographic, behavioural and CVD risk factors had little effect on the results. The HR of MI for smokers (1–9 cigarettes/day) compared with non-smokers with cotinine ≤0.05 ng/ml was 2.14 (1.39 to 3.52) and 1.03 (0.52 to 2.04) for stroke.

Conclusions

In contemporary older men and women, SHS exposure (predominantly at low levels) was not related to CHD or stroke risks, but we cannot rule out the possibility of modest effects at higher exposure levels.

Urine cotinine underestimates exposure to the tobacco-derived lung carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone in passive compared with active smokers

OBJECTIVES

Cotinine and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) are widely used biomarkers for tobacco-derived nicotine and the lung carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), respectively. The discrepancy between cotinine levels in relation to disease risk comparing active versus passive smoking suggests a nonlinear tobacco smoke dose-response and/or that cotinine is not providing an accurate measure of exposure to the toxic constituents of secondhand tobacco smoke.

METHODS

Cotinine and NNAL were measured in the urine of 373 active smokers and 228 passive smokers.

RESULTS

Average cotinine levels were 1,155 (interquartile range, 703-2,715) for active smokers and 1.82 (0.45-7.33) ng/mg creatinine for passive smokers. Average NNAL levels were 183 (103-393) and 5.19 (2.04-11.6) pg/mg creatinine, respectively. NNAL/cotinine ratio in urine was significantly higher for passive smokers when compared with active smokers (2.85 × 10(3) versus 0.16 × 10(3), P < 0.0001).

CONCLUSIONS

Passive smoking is associated with a much higher ratio of NNAL/cotinine in the urine compared with active smoking.

IMPACT

Cotinine measurement leads to an underestimation of exposure to the carcinogen NNK from secondhand smoke when compared with active smoking.

Objectively measured secondhand smoke exposure and risk of cardiovascular disease: what is the mediating role of inflammatory and hemostatic factors?

OBJECTIVES

The aim of this study was to examine the association between objectively measured secondhand smoke (SHS) exposure and incident cardiovascular disease (CVD) death and assess the extent to which this association can be explained through novel circulating markers of inflammation and hemostasis.

BACKGROUND

Existing evidence suggests there is an association between SHS and CVD risk, although the mechanisms remain poorly understood.

METHODS

In a prospective study of 13,443 participants living in England and Scotland (age 53.5 +/- 12.6 years, 52.3% women), we measured salivary cotinine (an objective marker of SHS exposure) and novel CVD biomarkers (C-reactive protein, fibrinogen) at baseline.

RESULTS

Of the sample, 20.8% had high SHS exposure on the basis of elevated levels of salivary cotinine (range 0.71 to 14.99 ng/ml). During a mean follow-up of 8 years, there were 1,221 all-cause deaths and 364 CVD deaths. High SHS was associated with all-cause (age-adjusted hazard ratio [HR]: 1.25, 95% confidence interval [CI]: 1.02 to 1.53) and CVD death (age-adjusted HR: 1.21, 95% CI: 0.85 to 1.73). High SHS was also associated with elevated CRP, which explained 48% of the association between SHS and CVD death. The excess risk of CVD associated with active smoking was exaggerated in relation to self report (age-adjusted HR: 3.27, 95% CI: 2.48 to 4.31) compared with objective assessment (age-adjusted HR: 2.44, 95% CI: 1.75 to 3.40).

CONCLUSIONS

Among a large representative sample of British adults we observed elevated levels of low-grade inflammation in otherwise healthy participants exposed to high SHS, and this partly explained their elevated risk of CVD death.

Short term impact of smoke-free legislation in England: retrospective analysis of hospital admissions for myocardial infarction

OBJECTIVE

To measure the short term impact on hospital admissions for myocardial infarction of the introduction of smoke-free legislation in England on 1 July 2007.

DESIGN

An interrupted time series design with routinely collected hospital episode statistics data. Analysis of admissions from July 2002 to September 2008 (providing five years' data from before the legislation and 15 months' data from after) using segmented Poisson regression.

SETTING

England. Population All patients aged 18 or older living in England with an emergency admission coded with a primary diagnosis of myocardial infarction.

MAIN OUTCOME MEASURES

Weekly number of completed hospital admissions.

RESULTS

After adjustment for secular and seasonal trends and variation in population size, there was a small but significant reduction in the number of emergency admissions for myocardial infarction after the implementation of smoke-free legislation (-2.4%, 95% confidence interval -4.06% to -0.66%, P=0.007). This equates to 1200 fewer emergency admissions for myocardial infarction (1600 including readmissions) in the first year after legislation. The reduction in admissions was significant in men (3.1%, P=0.001) and women (3.8%, P=0.007) aged 60 and over, and men (3.5%, P<0.01) but not women (2.5% P=0.38) aged under 60.

CONCLUSION

This study adds to a growing body of evidence that smoke-free legislation leads to reductions in myocardial infarctions. It builds on previous work by showing that such declines are observed even when underlying reductions in admissions and potential confounders are controlled for. The considerably smaller decline in admissions observed in England compared with many other jurisdictions probably reflects aspects of the study design and the relatively low levels of exposure to secondhand smoke in England before the legislation.

A sensitive enzyme immunoassay for measuring cotinine in passive smokers

BACKGROUND

Both active smoking and passive exposure to tobacco smoke are major risk factors for cardiovascular, pulmonary, and oncological diseases. The serum level of cotinine, a major proximate metabolite of nicotine, reflects active or passive exposure to tobacco smoke. However, currently available enzyme-linked immunosorbent assays (ELISAs) for cotinine have limited sensitivity, and a high-throughput quantification of the severity of passive exposure to tobacco smoke has not been possible thus far.

METHODS

We generated a phage display of combinatorial antibody library, from which we selected a recombinant antibody against cotinine, developed a sensitive ELISA using this antibody, and evaluated the method in a clinical setting and an animal model.

RESULTS

The limits of detection and the lower limit of quantification were 31pg/mL and 1ng/mL cotinine, respectively. The intra- and inter-assay precisions based on three quality control samples were 3.8-13.5% and 14.0-15.0%, respectively. No significant interference from nicotine, trans-3'-hydroxy cotinine, tobacco alkaloids, or other serum components was found. When we applied our ELISA to serum samples from 36 volunteers, the serum cotinine levels were clustered into two groups, which exactly corresponded to their smoking behavior and this ELISA yielded reproducible and accurate results, which were comparable to those of LC/MS in a split assay. In animal studies, we were able to distinguish between rats injected with a nicotine dose equivalent to that of passive exposure to tobacco and rats without exposure.

CONCLUSION

The competitive ELISA described here is useful for the detection and quantification of the severity of risk of passive smoking.

Assessing the effects of the introduction of the New Zealand Smokefree Environment Act 2003 on acute myocardial infarction hospital admissions in Christchurch, New Zealand

OBJECTIVE

To examine trends in Acute Myocardial Infarction (AMI) hospital admissions in Christchurch, New Zealand before and after the implementation of the New Zealand Smokefree Environments Act 2003 in December 2004.

METHODS

Data on AMI hospital admissions to Christchurch Public Hospital were extracted for the period 2003 to 2006. Poisson regression was used to calculate rate ratios by comparing for AMI rates of hospital admissions before (2003/04) and after (2005/06) the introduction of the Smokefree legislation, and to assess whether there was a significant change over time.

RESULTS

The introduction of the smokefree legislation was associated with a 5% reduction in AMI admissions. The 55-74 age group recorded the greatest decrease in admissions (9%) and this figure rose to 13% among never smokers in this group. Reductions were more marked for men. Adding the effects of area deprivation increased the reduction to 21% among 55-74 year olds living in more affluent (quintile 2) areas. Overall however, the statistical association of changing levels of AMI admissions with smoking status and with deprivation was not consistently significant.

CONCLUSION

At this early stage following the smokefree legislation, there are hints emerging of a positive impact on AMI admissions but these suggestions cannot yet be treated with certainty. Further research could usefully evaluate the longer-term effects of smoking legislation on the prevalence of smoking and exposure to second hand smoke, especially in more deprived urban communities.

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.

Cardiovascular disease in women

Cardiovascular disease (CVD) remains the most important health issue facing women and continues to be their number one cause of morbidity and mortality. Women are disproportionately affected by CVD compared with men. It is diagnosed less often and treated less aggressively in the inpatient and outpatient settings; as a result, women have poorer outcomes. It is therefore imperative that physicians take steps to screen women for the risks associated with CVD and actively education them on primary and secondary prevention.

Declines in acute myocardial infarction after smoke-free laws and individual risk attributable to secondhand smoke

BACKGROUND

The estimated effects of recent pubic and workplace smoking restriction laws suggest that they produce significant declines in community rates of heart attack. The consistency of these declines with existing estimates of the relative risk of heart attack in individuals attributable to passive smoking exposure is poorly understood. The objective is to determine the consistency of estimates of reductions in community rates of heart attacks resulting from smoking restriction laws with estimates of the relative risk of heart disease in individuals exposed to passive smoking.

METHODS AND RESULTS

Meta-analyses of existing estimates of declines in community rates were compared with a mathematical model of the relationship between individual risk and community rates. The outcome measure is the ratio of community rates of acute myocardial infarction (after divided by before implementation of a smoking restriction law). There is a significant drop in the rate of acute myocardial infarction hospital admissions associated with the implementation of strong smoke-free legislation. The primary reason for heterogeneity in results of different studies is the duration of follow-up after adoption of the law. The pooled random-effects estimate of the rate of acute myocardial infarction hospitalization 12 months after implementation of the law is 0.83 (95% confidence interval, 0.80 to 0.87), and this benefit grows with time. This drop in admissions is consistent with a range of plausible individual risk and exposure scenarios.

CONCLUSIONS

Passage of strong smoke-free legislation produces rapid and substantial benefits in terms of reduced acute myocardial infarctions, and these benefits grow with time.

Secondhand smoke (SHS) exposure is associated with circulating markers of inflammation and endothelial function in adult men and women

AIMS

Secondhand smoke (SHS) exposure is associated with elevated CHD risks. Yet the pathways through which this may operate have not been investigated in epidemiologic studies with objective SHS exposure measures and a wide range of CHD risk factors associated with active smoking. Therefore we investigate associations between SHS exposure and CHD risk factors, to clarify how SHS exposure may raise risk of CHD.

METHODS

Cross-sectional population-based study of 5029 men and women aged 59-80 years from primary care practices in Great Britain. Smoking, behavioural and demographic information was reported in questionnaires; nurses made physical measurements and took blood samples for analysis of serum cotinine and markers of inflammation, hemostasis and endothelial dysfunction.

RESULTS

Active cigarette smokers had lower albumin and higher triglycerides, CRP, IL-6, white cell count, fibrinogen, blood viscosity, factor VIII, VWF and t-PA than non-smokers. Among non-smokers, serum cotinine levels were independently positively associated with CRP, fibrinogen, factor VIII, VWF and t-PA and inversely associated with albumin, after adjustment for age, gender, social and behavioural factors. The differences in CRP, fibrinogen and albumin between cotinine < or =0.05 and >0.7 ng/ml were one-third to one half the size of differences between cotinine < or =0.05 ng/ml and current smokers, but were of similar magnitude for VWF and t-PA.

CONCLUSIONS

Endothelial, inflammatory and haemostatic markers related to CHD risk showed independent associations with SHS exposure in the same direction as those for active smoking. Results aid understanding of the associations between SHS exposure and elevated CHD risks.

Urine nicotine metabolite concentrations in relation to plasma cotinine during low-level nicotine exposure

INTRODUCTION

Plasma or saliva cotinine concentrations are used widely as biomarkers of secondhand smoke (SHS) exposure and have been associated with the risk of SHS-related disease. Concentrations of cotinine and other nicotine metabolites are considerably higher in urine than in plasma or saliva, making chemical analysis easier. In addition, urine is often more convenient to collect in some SHS exposure studies. The optimal use of nicotine metabolites in urine, singly or in combination, with or without correction for urine creatinine concentration, to estimate plasma cotinine concentration with low-level nicotine exposure has not been determined.

METHODS

We dosed 36 nonsmokers with 100, 200, or 400 microg deuterium-labeled nicotine (simulating exposure to SHS) by mouth daily for 5 days and then measured plasma and urine cotinine and metabolites at various intervals over 24 hr.

RESULTS

A plasma cotinine concentration of 1 ng/ml corresponds on average to a daily intake of 100 microg nicotine. Cotinine concentrations in urine averaged four to five times those in plasma. Correction of urine cotinine for creatinine concentration improved the correlation between urine and plasma cotinine. Measuring multiple cotinine metabolites in urine did not improve the correlation with plasma cotinine, compared with the use of urine cotinine alone.

DISCUSSION

Measurement of urine cotinine corrected for creatinine concentration appears to be the best predictor of plasma cotinine.

Changes in environmental tobacco smoke (ETS) exposure over a 20-year period: cross-sectional and longitudinal analyses

AIMS

To examine long-term changes in environmental tobacco smoke (ETS) exposure in British men between 1978 and 2000, using serum cotinine.

DESIGN

Prospective cohort: British Regional Heart Study.

SETTING

General practices in 24 towns in England, Wales and Scotland.

PARTICIPANTS

Non-smoking men: 2125 studied at baseline [questionnaire (Q1): 1978-80, aged 40-59 years], 3046 studied 20 years later (Q20: 1998-2000, aged 60-79 years) and 1208 studied at both times. Non-smokers were men reporting no current smoking with cotinine < 15 ng/ml at Q1 and/or Q20.

MEASUREMENTS

Serum cotinine to assess ETS exposure.

FINDINGS

In cross-sectional analysis, geometric mean cotinine level declined from 1.36 ng/ml [95% confidence interval (CI): 1.31, 1.42] at Q1 to 0.19 ng/ml (95% CI: 0.18, 0.19) at Q20. The prevalence of cotinine levels < or = 0.7 ng/ml [associated with low coronary heart disease (CHD) risk] rose from 27.1% at Q1 to 83.3% at Q20. Manual social class and northern region of residence were associated with higher mean cotinine levels both at Q1 and Q20; older age was associated with lower cotinine level at Q20 only. Among 1208 persistent non-smokers, cotinine fell by 1.47 ng/ml (95% CI: 1.37, 1.57), 86% decline. Absolute falls in cotinine were greater in manual occupational groups, in the Midlands and Scotland compared to southern England, although percentage decline was very similar across groups.

CONCLUSIONS

A marked decline in ETS exposure occurred in Britain between 1978 and 2000, which is likely to have reduced ETS-related disease risks appreciably before the introduction of legislation banning smoking in public places.

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.

Second-hand smoke exposure in Canada: prevalence, risk factors, and association with respiratory and cardiovascular diseases

OBJECTIVES

The aims of the present study were to estimate the prevalence of second-hand smoke exposure in Canada, to identify sociodemographic risk factors for second-hand smoke exposure, and to examine the relationship between second-hand smoke exposure and respiratory and cardiovascular diseases.

METHODS

Data from the 2000/2001 Statistics Canada Canadian Community Health Survey (n=130,880, aged 12 years or older) were analyzed. Second-hand smoke exposure was based on self-report within the past month. The presence of chronic health conditions was also based on self-report. Because ex-smokers would be expected a priori to have poorer health than never-smokers, the analysis was stratified by previous smoking status.

RESULTS

Approximately 25% of never-smokers and 30% of ex-smokers self-reported recent second-hand smoke exposure. The following factors were identified as risk factors for second-hand smoke exposure: men; residences in Quebec, Atlantic Canada and the Territories; younger ages; nonimmigrant status; low education and income levels; social assistance receipt; and households without children younger than 12 years of age. After controlling for potential confounders, both never- and ex-smokers exposed to second-hand smoke had significantly higher odds of self-reporting asthma (20% to 30%) and chronic bronchitis (50%) than those not exposed to second-hand smoke. Among ex-smokers, those exposed to second-hand smoke also had significantly higher odds of self-reporting hypertension (20%) than those not exposed to second-hand smoke. No associations were observed between second-hand smoke exposure and emphysema or heart disease.

CONCLUSIONS

Self-reported recent second-hand smoke exposure in Canada in 2000/2001 was high, and was associated with asthma, chronic bronchitis and hypertension in never- and ex-smokers. Potential causal associations and public health implications warrant additional research.

Renal, vascular and cardiac fibrosis in rats exposed to passive smoking and industrial dust fibre amosite

Passive smoking is an independent risk factor for cardiovascular diseases. Industrial fibrous dust, e.g. the asbestos group member, amosite, causes lung cancer and fibrosis. No data are available on renal involvement after inhalational exposure to these environmental pollutants or of their combination, or on cardiovascular and renal toxicity after exposure to amosite. Male Wistar rats were randomized into four groups (n= 6): control and amosite group received initially two intratracheal instillations of saline and amosite solution, respectively. Smoking group was subjected to standardized daily exposure to tobacco smoke for 2 hrs in a concentration resembling human passive smoking. Combined group was exposed to both amosite and cigarette smoke. All rats were killed after 6 months. Rats exposed to either amosite or passive smoking developed significant glomerulosclerosis and tubulointerstitial fibrosis. Combination of both exposures had additive effects. Histomorphological changes preceded the clinical manifestation of kidney damage. In both groups with single exposures, marked perivascular and interstitial cardiac fibrosis was detected. The additive effect in the heart was less pronounced than in the kidney, apparent particularly in changes of vascular structure. Advanced oxidation protein products, the plasma marker of the myeloperoxidase reaction in activated monocytes/macrophages, were increased in all exposed groups, whereas the inflammatory cytokines did not differ between the groups. In rats, passive smoking or amosite instillation leads to renal, vascular and cardiac fibrosis potentially mediated via increased myeloperoxidase reaction. Combination of both pollutants shows additive effects. Our data should be confirmed in subjects exposed to these environmental pollutants, in particular if combined.

Passive smoking and risk of peripheral arterial disease and ischemic stroke in Chinese women who never smoked

BACKGROUND

The association between secondhand smoke (SHS) and risk of peripheral arterial disease (PAD) and stroke remains uncertain.

METHODS AND RESULTS

We examined the relationship between SHS and cardiovascular diseases, particularly PAD and stroke, in Chinese women who never smoked from a population-based cross-sectional study in Beijing, China. SHS exposure was defined as exposure to another person's tobacco smoke at home or in the workplace. Cardiovascular disease events included coronary heart disease, stroke, and PAD. PAD was defined by signs of intermittent claudication as measured by the World Health Organization Rose questionnaire and an ankle-brachial index of <0.90. Among 1209 women who never smoked, 39.5% were exposed to SHS at home or in workplaces. Those individuals who were exposed to SHS had a significantly higher risk of coronary heart disease (adjusted odds ratio [OR], 1.69; 95% CI, 1.31 to 2.18) and ischemic stroke (OR, 1.56; 95% CI, 1.03 to 2.35) than those never exposed to SHS after adjustment for 13 potential risk factors. The adjusted ORs of PAD defined by intermittent claudication, by ankle-brachial index <0.90, and by either intermittent claudication or ankle-brachial index <0.90 were 1.87 (95% CI, 1.30 to 2.68), 1.47 (95% CI, 1.07 to 2.03), and 1.67 (95% CI, 1.23 to 2.16), respectively. Dose-response relationships were found between SHS exposure amount (cigarettes per day) and duration (minutes per day) and increasing prevalence of coronary heart disease, ischemic stroke, and PAD.

CONCLUSIONS

In China, SHS exposure in women is highly prevalent. In addition to being a risk factor for coronary heart disease, SHS should be considered an important risk factor for ischemic stroke and PAD in nonsmoking women.

Passive tobacco exposure may impair symptomatic improvement in patients with chronic angina undergoing enhanced external counterpulsation

Background

The adverse effects of tobacco abuse on cardiovascular outcomes are well-known. However, the impact of passive smoke exposure on angina status and therapeutic response is less well-established. We examined the impact of second-hand smoke (SHS) exposure on symptomatic improvement in patients with chronic ischemic coronary disease undergoing enhanced external counterpulsation (EECP).

Methods

This observational study included 1,026 non-smokers (108 exposed and 918 not-exposed to SHS) from the Second International EECP Patient Registry. We also assessed angina response in 363 current smokers. Patient demographics, symptomatic improvement and quality of life assessment were determined by self-report prior and after EECP treatment.

Results

Non-smoking SHS subjects had a lower prevalence of prior revascularization (85% vs 90%), and had an increased prevalence of stroke (13% vs 7%) and prior smoking (72% vs 61%; all p < 0.05) compared to non-smokers without SHS exposure. Despite comparable degrees of coronary disease, baseline angina class, medical regimens and side effects during EECP, fewer SHS non-smokers completed a full 35-hour treatment course (77% vs 85%, p = 0.020) compared to non-smokers without SHS. Compared to non-smokers without SHS, non-smoking SHS subjects had less angina relief after EECP (angina class decreased ≥ 1 class: 68% vs 79%; p = 0.0082), both higher than that achieved in current smokers (66%). By multivariable logistic regression, SHS exposure was an independent predictor of failure to symptomatic improvement after EECP among non-smokers (OR 1.81, 95% confidence intervals 1.16–2.83).

Conclusion

Non-smokers with SHS exposure had an attenuated improvement in anginal symptoms compared to those without SHS following EECP.

Mortality attributable to passive smoking in Spain, 2002

OBJECTIVE

Exposure to environmental tobacco smoke (ETS) is associated with a variety of health effects, including lung cancer and ischaemic heart disease. The objective of this study was to estimate the number of deaths caused by exposure to ETS among non-smokers in Spain during the year 2002

METHODS

Prevalence of ETS exposure among never smokers was gathered from three region based health interview surveys. The relative risks of lung cancer and ischaemic heart diseases were selected from three meta-analyses. Population attributable risk (PAR) was computed using a range of prevalences (minimum-maximum). The number of deaths attributable to ETS was calculated by applying PARs to mortality not attributable to active smoking in 2002. The analyses were stratified by sex, age and source of exposure (home, workplace and both combined). In addition, a sensitivity analysis was performed for different scenarios.

RESULTS

Among men, deaths attributable to ETS ranged from 408 to 1703. From 247 to 1434 of these deaths would be caused by the exposure only at home, 136-196 by exposure only in the workplace and 25-73 by exposure at both home and the workplace. Among women, the number of attributable deaths ranged from 820 to 1534. Between 807 and 1477 of these deaths would be caused by exposure only at home, 9-32 by exposure only in the workplace and 4-25 by exposure both at home and in the workplace.

CONCLUSION

Exposure to ETS at home and at work in Spain could be responsible for 1228-3237 of deaths from lung cancer and ischaemic heart disease. These data confirm that passive smoking is an important public health problem in Spain that needs urgent attention.

Tobacco industry efforts undermining evidence linking secondhand smoke with cardiovascular disease

BACKGROUND

The scientific consensus that secondhand smoke (SHS) increases cardiovascular disease (CVD) risk by 30% is based on epidemiological and biological evidence. The tobacco industry has contested this evidence that SHS causes CVD, but how and why they have done it has not been described.

METHODS AND RESULTS

About 50 million pages of tobacco industry documents were searched using general keywords and names of industry consultants and scientists. Tobacco industry-funded epidemiological analyses of large data sets were used to argue against an epidemiological association between SHS and CVD and smoke-free regulations, but these analyses all suffered from exposure misclassification problems that biased the results toward the null. More recent industry-funded publications report an increased risk of CVD associated with SHS but claim a low magnitude of risk. When early tobacco industry-funded work demonstrated that SHS increased atherosclerosis, the industry criticized the findings and withdrew funding. RJ Reynolds focused on attacking the biological plausibility of the association between SHS and CVD by conducting indirect platelet aggregation studies, exposure chamber experiments, and literature reviews. Although these studies also suffered from exposure misclassification problems, several produced results that were consistent with a direct effect of SHS on blood and vascular function. Instead, RJ Reynolds attributed these results to an unproven epinephrine-related stress response from odor or large smoke exposure, which supported their regulatory and "reduced-harm" product development efforts. Philip Morris' recent "reduced-harm" efforts seem supportive of a similar corporate agenda.

CONCLUSIONS

The tobacco industry attempted to undermine the evidence that SHS causes CVD to fight smoke-free regulations while developing approaches to support new products that claim to reduce harm. The industry interest in preserving corporate viability has affected the design and interpretation of their cardiovascular studies, indicating the need for great caution in current debates about future tobacco industry regulation and development of reduced-harm tobacco products.