Cigarette smoking among spouses: another risk factor for stroke in women

Health effects associated with exposure to secondhand smoke: a Burden of Proof study

Despite a gradual decline in smoking rates over time, exposure to secondhand smoke (SHS) continues to cause harm to nonsmokers, who are disproportionately children and women living in low- and middle-income countries. We comprehensively reviewed the literature published by July 2022 concerning the adverse impacts of SHS exposure on nine health outcomes. Following, we quantified each exposure-response association accounting for various sources of uncertainty and evaluated the strength of the evidence supporting our analyses using the Burden of Proof Risk Function methodology. We found all nine health outcomes to be associated with SHS exposure. We conservatively estimated that SHS increases the risk of ischemic heart disease, stroke, type 2 diabetes and lung cancer by at least around 8%, 5%, 1% and 1%, respectively, with the evidence supporting these harmful associations rated as weak (two stars). The evidence supporting the harmful associations between SHS and otitis media, asthma, lower respiratory infections, breast cancer and chronic obstructive pulmonary disease was weaker (one star). Despite the weak underlying evidence for these associations, our results reinforce the harmful effects of SHS on health and the need to prioritize advancing efforts to reduce active and passive smoking through a combination of public health policies and education initiatives.

Secondhand smoke and the risk of incident cardiovascular disease among never-smoking women

The prospective association between secondhand smoke (SHS) and the risk of incident cardiovascular disease (CVD) remains unclear. This study was the first to examine the association between SHS and risks of ischemic heart disease (IHD), stroke, and total CVD in a large cohort in Asia. The study followed 24,232 never-smoking women aged 40-59 from around Japan (Akita, Iwate, Nagano, Niigata, Ibaraki, Kochi, Nagasaki, and Okinawa prefectures). Their husbands were classified into never, former, and current smokers. After adjustment for age, body mass index, alcohol consumption, histories of hypertension and diabetes mellitus, medication use for hyperlipidemia, menopausal status, and public health center areas, the hazard ratios (HRs) of CVD according to husbands' smoking status were estimated by Cox proportional hazards models. During the 440,360 person-years follow-up, 846 women had total CVDs (103 IHDs, 744 strokes). The proportional hazard assumption was not assured during the total follow-up from 1990 to 2012, but so was then the follow-up of < and ≥ 10 person-years were examined separately. The multivariable HRs (95% confidence intervals) associated with husbands' current versus non-current smoking was 2.02 (1.19-3.45) for IHD, 1.18 (0.98-1.42) for stroke, and 1.25 (1.05-1.49) for total CVD in the follow-up of ≥10 person-years. The SHS from husbands may raise the risk of IHD among middle-aged never-smoking women.

The interaction effects of secondhand smoke exposure and overweight on the prevalence of hypertension in Chinese coke oven workers and NHANES participants (2013-2016)

BACKGROUND

The prevalence of hypertension may be affected by environmental pollution and personal behavior.

OBJECTIVES

We aimed to evaluate the interaction effects of secondhand smoke exposure and overweight on hypertension.

METHODS

In this cross-sectional study, a total of 627 workers from a coking plant in China and 1011 individuals from the NHANES database in the United States from 2013 to 2016 were selected as the research participants. The concentrations of 11 urinary polycyclic aromatic hydrocarbons (PAHs) metabolites and 3 tobacco metabolites were measured. An interaction effect was tested in the modified Poisson regression models.

RESULTS

For smokers among Chinese coke oven workers, the only statistically significant positive association was with hypertension in the highest tertile of nicotine metabolized ratio (NMR) (PR: 1.539, 95% CI: 1.013-2.337). Nonsmoking Chinese workers with 3rd tertile urinary nicotine levels were associated with a 114.8% significantly increased prevalence of hypertension (PR: 2.148, 95% CI: 1.025-4.500) compared to nonsmokers 1st tertile with nicotine levels. Association between tobacco exposure and hypertension is possibly modified by PAHs exposure (PR: 2.335, 95% CI: 0.933-5.841). Nonsmokers in the NHANES database with high urinary nicotine levels were associated with a 17.3% significantly increased prevalence of hypertension (PR: 1.173, 95% CI: 1.028-1.338) compared to those with low nicotine levels. We observed that overweight people with high nicotine levels had a significantly higher likelihood of hypertension than no overweight people with low nicotine levels among nonsmoking Chinese coke oven workers and NHANES participants (PR = 4.686, 95% CI: 1.488-14.754; PR = 1.251, 95% CI: 1.039-1.506).

CONCLUSIONS

Tobacco exposure and overweight are important risk factors for hypertension, and secondhand smoke exposure and overweight have an interactive effect on the incidence of hypertension in nonsmoking Chinese coke oven workers and NHANES participants.

Comparison of Brain Magnetic Resonance Imaging Lesions in Opium Addict and Non-addict Patients with Thrombotic Stroke: A Case-Control Study

Background

There is no consensus on the effect of opium on stroke yet. Some studies show the negative effects of opium on ischemic strokes. Here, we attempt to compare the volume of lesions in opium addict and non-addict patients with thrombotic stroke.

Methods

This case-control study was conducted on patients with thrombotic stroke at Shafa Hospital in Kerman, Iran. The diagnosis was confirmed by clinical examinations, imaging, and laboratory tests. The volume of lesions was calculated by magnetic resonance imaging (MRI), and the data were analyzed by descriptive statistics, Mann-Whitney U test, Chi-square test, and linear regression analysis.

Findings

A total of 60 patients were studied, 30 of whom were opium addicts and the rest were non-addicts. The mean volume of the lesion was 46.008350 ± 7.488990 (in the addict group) and 31.023335 ± 1.441570 (in the non-addict group), indicating a significant difference between the two groups (P = 0.005). Regression analysis results showed a significant relationship between the volume of stroke with opium addiction (P = 0.017), ischemic heart diseases (IHDs) (P = 0.006), hyperlipidemia (HLP) (P = 0.016), age (P = 0.035), and smoking (P = 0.044).

Conclusion

The results of this study showed a higher volume of lesion in opium-addict patients compared to that in non-addicts as an indicator of stroke severity.

Secondhand smoking and neurological disease: a meta-analysis of cohort studies

BACKGROUND

The results of studies on the relationship between secondhand smoking and neurological disease remain controversial. We conducted a meta-analysis to explore the association between secondhand smoking and risk of neurological disease.

METHODS

Literature search was performed in PubMed, Embase and Web of Science through December 2019. We included cohort studies which examined the association between secondhand smoking and risk of neurological disease. According to the type of neurological disease, summary relative risks (RRs) with 95% confidence intervals (CIs) of stroke, cognitive impairment and Parkinson disease (PD) for secondhand smoking exposure were calculated.

RESULTS

A total of 14 unique articles (n=697,185 participants) were eventually included in the analysis. When all studies were pooled, the RR of stroke for secondhand smoking exposure was 1.20 (95% CI: 1.04, 1.38). When studies included only non-smokers, the pooled RR of stroke was 1.20 (95% CI: 1.05, 1.37). Summary RRs of cognitive impairment and PD for secondhand smoking exposure were 1.43 (95% CI: 1.02, 2.00) and 0.83 (95% CI: 0.72, 0.95), respectively. Summary RRs did not change significantly when excluding one study at a time.

CONCLUSIONS

Secondhand smoking was found to be positively associated with risks of stroke and cognitive impairment, while inversely associated with risk of PD. Overall, our finding is a reminder of the need to step up smoking bans to prevent health damage, and also suggests that more researches on biological mechanisms whereby secondhand smoking affect PD may be beneficial to PD prevention and treatment.

Association between secondhand smoke exposure and hypertension: nearly as large as smoking

: Active smoking is a widely accepted risk factor for cardiovascular disease and is recognized as a major public health problem. Passive smoking, also known as secondhand smoke exposure (SHSE), is thought to have similar cardiovascular consequences and the risk has been postulated to be equivalent to that of active smoking. A major component of this risk involves the connection with chronic hypertension. There are several population-based observational studies investigating the relationship between SHSE and chronic hypertension, all of which demonstrate a positive association. Given that SHSE appears to be a risk factor for chronic hypertension, SHSE should also be a risk factor for hypertensive end-organ disease. Many studies have sought to investigate this relationship, but this has yet to be fully elucidated. In this review, we focus on the current evidence regarding the association between SHSE and hypertension as well as exploration of the links between SHSE and hypertensive end-organ damage.

Association of secondhand tobacco smoke exposure during childhood on adult cardiovascular disease risk among never-smokers

PURPOSE

Adult secondhand tobacco smoke (SHS) exposure is related to stroke and coronary heart disease (CHD) risk, but long-term effects are less clear. We evaluated whether childhood SHS exposure affects subsequent stroke or CHD risk among adult black and white never-smokers followed for stroke and CHD.

METHODS

In this prospective cohort study, inverse probability weights were calculated to correct for bias due to attrition and survey nonresponse. Cox proportional hazards models were used to assess hazard ratios and 95% confidence intervals for stroke or CHD, separately, by number of childhood household smokers.

RESULTS

Of 13,142 eligible participants, 6136 had childhood SHS exposure assessed. Baseline mean (SD) age was 63.5 (9.0), 65% were female, 30% black, 46% reported 0 childhood household smokers, 36% reported 1, and 18% reported 2+. In 60,649 person-years, 174 strokes were observed (2.9% of participants), and in 45,195 person-years, 114 CHD events were observed (2.1% of participants). The weighted and adjusted hazard ratios (95% confidence intervals) of stroke for 2+ versus 0 childhood household smokers was 1.66 (1.29-2.13) and was 1.15 (0.82-1.59) for CHD.

CONCLUSIONS

We observed a significant association between childhood SHS exposure and stroke, but not CHD, after age 45 years and adjusting for missing information.

Interaction of diabetes and smoking on stroke: a population-based cross-sectional survey in China

OBJECTIVES

Diabetes and smoking are known independent risk factors for stroke; however, their interaction concerning stroke is less clear. We aimed to explore such interaction and its influence on stroke in Chinese adults.

DESIGN

Cross-sectional study.

SETTING

Community-based investigation in Xuzhou, China.

PARTICIPANTS

A total of 39 887 Chinese adults who fulfilled the inclusion criteria were included.

METHODS

Participants were selected using a multistage stratified cluster method, and completed self-reported questionnaires on stroke and smoking. Type 2 diabetes mellitus (DM2) was assessed by fasting blood glucose or use of antidiabetic medication. Interaction, relative excess risk owing to interaction (RERI), attributable proportion (AP) and synergy index (S) were evaluated using a logistic regression model.

RESULTS

After adjustment for age, sex, marital status, educational level, occupation, physical activity, body mass index, hypertension, family history of stroke, alcohol use and blood lipids, the relationships between DM2 and stroke, and between smoking and stroke, were still significant: ORs were 2.75 (95% CI 2.03 to 3.73) and 1.70 (95% CI 1.38 to 2.10), respectively. In subjects with DM2 who smoked, the RERI, AP and S values (and 95% CIs) were 1.80 (1.24 to 3.83), 0.52 (0.37 to 0.73) and 1.50 (1.18 to 1.84), respectively.

CONCLUSIONS

The results suggest there are additive interactions between DM2 and smoking and that these affect stroke in Chinese adults.

Environmental tobacco smoke exposure and heart disease: A systematic review

AIM

To review evidence relating passive smoking to heart disease risk in never smokers.

METHODS

Epidemiological studies were identified providing estimates of relative risk (RR) of ischaemic heart disease and 95%CI for never smokers for various indices of exposure to environmental tobacco smoke (ETS). “Never smokers” could include those with a minimal smoking experience. The database set up included the RRs and other study details. Unadjusted and confounder-adjusted RRs were entered, derived where necessary using standard methods. The fixed-effect and random-effects meta-analyses conducted for each exposure index included tests for heterogeneity and publication bias. For the main index (ever smoking by the spouse or nearest equivalent, and preferring adjusted to unadjusted data), analyses investigated variation in the RR by sex, continent, period of publication, number of cases, study design, extent of confounder adjustment, availability of dose-response results and biomarker data, use of proxy respondents, definitions of exposure and of never smoker, and aspects of disease definition. Sensitivity analyses were also run, preferring current to ever smoking, or unadjusted to adjusted estimates, or excluding certain studies.

RESULTS

Fifty-eight studies were identified, 20 in North America, 19 in Europe, 11 in Asia, seven in other countries, and one in 52 countries. Twenty-six were prospective, 22 case-control and 10 cross-sectional. Thirteen included 100 cases or fewer, and 11 more than 1000. For the main index, 75 heterogeneous (P < 0.001) RR estimates gave a combined random-effects RR of 1.18 (95%CI: 1.12-1.24), which was little affected by preferring unadjusted to adjusted RRs, or RRs for current ETS exposure to those for ever exposure. Estimates for each level of each factor considered consistently exceeded 1.00. However, univariate analyses revealed significant (P < 0.001) variation for some factors. Thus RRs were lower for males, and in North American, larger and prospective studies, and also where the RR was for spousal smoking, fatal cases, or specifically for IHD. For case-control studies RRs were lower if hospital/diseased controls were used. RRs were higher when diagnosis was based on medical data rather than death certificates or self-report, and where the never smoker definition allowed subjects to smoke products other than cigarettes or have a limited smoking history. The association with spousal smoking specifically (1.06, 1.01-1.12, n = 34) was less clear in analyses restricted to married subjects (1.03, 0.99-1.07, n = 23). In stepwise regression analyses only those associations with source of diagnosis, study size, and whether the spouse was the index, were independently predictive (at P < 0.05) of heart disease risk. A significant association was also evident with household exposure (1.19, 1.13-1.25, n = 37). For those 23 studies providing dose-response results for spouse or household exposure, 11 showed a significant (P < 0.05) positive trend including the unexposed group, and two excluding it. Based on fewer studies, a positive, but non-significant (P > 0.05) association was found for workplace exposure (RR = 1.08, 95%CI: 0.99-1.19), childhood exposure (1.12, 0.95-1.31), and biomarker based exposure indices (1.15, 0.94-1.40). However, there was a significant association with total exposure (1.23, 1.12-1.35). Some significant positive dose-response trends were also seen for these exposure indices, particularly total exposure, with no significant negative trends seen. The evidence suffers from various weaknesses and biases. Publication bias may explain the large RR (1.66, 1.30-2.11) for the main exposure index for smaller studies (1-99 cases), while recall bias may explain the higher RRs seen in case-control and cross-sectional than in prospective studies. Some bias may also derive from including occasional smokers among the “never smokers”, and from misreporting smoking status. Errors in determining ETS exposure, and failing to update exposure data in long term prospective studies, also contribute to the uncertainty. The tendency for RRs to increase as more factors are adjusted for, argues against the association being due to uncontrolled confounding.

CONCLUSION

The increased risk and dose-response for various exposure indices suggests ETS slightly increases heart disease risk. However heterogeneity, study limitations and possible biases preclude definitive conclusions.

Passive smoking and stroke in men and women: a national population-based case-control study in China

An association between passive smoking and stroke is unclear in China, particularly the association with hemorrhagic stroke. This study included 16205 deaths due to stroke aged ≥30 years and 16205 non-stroke controls randomly selected and frequency-matched to cases on gender and age. Smoking of spouses, defined as ≥1 cigarette per day for up to 1 year, was taken as a measure of exposure to passive smoking of subjects that was retrospectively ascertained by interviewing surviving spouses. After adjustment for variables, passive smoking increased the risk of death by 10% (odds ratio (OR), 1.10; 95% confidence interval (CI), 1.05-1.16) for all strokes, by 10% (OR, 1.10; 95% CI, 1.04-1.16) for hemorrhagic stroke, and by 12% (OR, 1.12; 95% CI, 1.03-1.23) for ischemic stroke, compared with non-exposure. This finding was highly consistent in men or women and in smokers or non-smokers, and was generally consistent among zones of China despite geographic diversity. The risk significantly increased with exposure-years and quantity of cigarettes smoked daily by spouses. This study indicated that passive smoking is associated with deaths from all-type strokes. It is highly advisable for the government to promote strong tobacco prevention and cessation programs and smoke-free environments.

Environmental Tobacco Smoke Exposure and Risk of Stroke in Never Smokers: An Updated Review with Meta-Analysis

OBJECTIVES

The study aimed to review the epidemiological evidence relating environmental tobacco smoke exposure to stroke in never smokers.

METHODS

The study is similar to our review in 2006, with searches extended to March 2016.

RESULTS

Twelve further studies were identified. A total of 28 studies varied considerably in design, exposure indices used, and disease definition. Based on 39 sex-specific estimates and the exposure index current spousal exposure (or nearest equivalent), the meta-analysis gave an overall fixed-effect relative risk estimate of 1.23 (95% confidence interval: 1.16-1.31), with significant (P < .05) heterogeneity. There was no significant heterogeneity by sex, continent, fatality, disease end point, or degree of adjustment for potential confounding factors. Relative risks were less elevated in prospective studies (1.15, 1.06-1.24) than in case-control studies (1.44, 1.22-1.60) or cross-sectional studies (1.40, 1.21-1.61). They also varied by publication year, but with no trend. A significant increase was not seen in studies that excluded smokers of any tobacco (1.07, .97-1.17), but was seen for studies that included pipe- or cigar-only smokers, occasional smokers, or long-term former smokers. No elevation was seen for hemorrhagic stroke. Relative risk estimates were similar using ever rather than current exposure, or total rather than spousal exposure. Eleven studies provided dose-response estimates, the combined relative risk for the highest exposure level being 1.56 (1.37-1.79). Many studies have evident weaknesses, recall bias, and particularly publication bias being major concerns.

CONCLUSIONS

Although other reviewers inferred a causal relationship, we consider the evidence does not conclusively demonstrate this. We repeat our call for publication of data from existing large prospective studies.

Meta-analysis of the association between second-hand smoke exposure and ischaemic heart diseases, COPD and stroke

Background

Second-hand smoke (SHS) is the most important contaminant of indoor air in first world countries. The risks associated with SHS exposure are highly relevant, because many people are regularly, and usually involuntarily, exposed to SHS. This study aims to quantify the effects of SHS exposure. Therefore, its impact on ischaemic heart diseases (IHD), chronic obstructive pulmonary diseases (COPD) and stroke will be considered.

Methods

A systematic literature review was conducted to identify articles dealing with the association between SHS and the three outcomes IHD, COPD and stroke. Overall, 24 articles were included in a meta-analysis using a random effects model. Effect sizes stratified for sex and for both sexes combined were calculated.

Results

The synthesis of primary studies revealed significant effect sizes for the association between SHS exposure and all three outcomes. The highest RR for both sexes combined was found for COPD (RR = 1.66, 95 % CI: 1.38–2.00). The RR for both sexes combined was 1.35 (95 % CI: 1.22–1.50) for stroke and 1.27 (95 % CI: 1.10–1.48) for IHD. The risks were higher in women than in men for all three outcomes.

Conclusions

This is the first study to calculate effect sizes for the association between SHS exposure and the disease outcomes IHD, COPD, and stroke at once. Overall, the effect sizes are comparable with previous findings in meta-analyses and therefore assumed to be reliable. The results indicate the high relevance of public health campaigns and legislation to protect non-smokers from the adverse health effects attributable to SHS exposure.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-015-2489-4) contains supplementary material, which is available to authorized users.

Secondhand Smoke Exposure and Stroke: The Reasons for Geographic and Racial Differences in Stroke (REGARDS) Study

INTRODUCTION

Stroke is a major public health concern worldwide given the associated morbidity and mortality. Smoking is a risk factor for stroke, but the relationship between secondhand smoke (SHS) exposure and stroke has been inconsistent to date. The aim of the current study was to examine the association of SHS exposure and risk of stroke and its subtypes (ischemic and hemorrhagic stroke) among nonsmokers.

METHODS

Demographic and clinical characteristics were compared by SHS exposure status for African American and white nonsmokers aged ≥45 years in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study in 2014. Hazard ratios (HRs) and corresponding 95% CIs were calculated by Cox proportional hazards models to assess the relationship between SHS exposure and stroke risk.

RESULTS

Of the 21,743 participants (38% African American, 45% male), SHS exposure in the past year was reported by 23%. Compared with those without SHS exposure, exposed participants were more likely to be female, white, younger, and reside with a smoker (all p<0.001). A total of 428 incident strokes were observed from April 2003 to March 2012 during a mean follow-up of 5.6 years. The risk of overall stroke was increased 30% among those with SHS exposure after adjustment for other stroke risk factors (95% CI=2%, 67%). This relationship appeared to be driven by ischemic strokes.

CONCLUSIONS

SHS exposure is independently associated with an increased risk of stroke. Future studies are needed to confirm these findings and examine the role of long-term effects of SHS exposure on stroke outcomes.

Risk of all-cause mortality and cardiovascular disease associated with secondhand smoke exposure: a systematic review and meta-analysis

BACKGROUND

Emerging studies have assessed the association between secondhand smoke (SHS) exposure and cardiovascular disease (CVD) as well as all-cause mortality. However, findings were not consistent due to the heterogeneity of study characteristics.

METHODS

PubMed and Embase were searched through May 2014 for prospective cohort and case-control studies investigating the associations of SHS exposure in never smokers with all-cause mortality and the risk of CVD. The main analysis was performed in studies using self-reported SHS exposure and secondary analysis was performed in studies using objectively measured SHS exposure. Summary estimates were calculated using random-effects models.

RESULTS

Twenty-three prospective and 17 case-control studies were included. The pooled relative risks (RR) for never smokers exposed to SHS in comparison with those unexposed were 1.18 [95% confidence interval (CI): 1.10-1.27] for all-cause mortality (12 studies), and 1.23 (1.16-1.31) for CVD (38 studies). The association of SHS exposure with CVD was markedly stronger among studies conducted in China (RR=1.65, 95% CI 1.27-2.13) than that in the US (RR=1.09, 95% CI 1.03-1.16). Studies using objectively measured SHS exposure demonstrated a slightly higher risk for CVD compared with those using self-reported SHS exposure.

CONCLUSIONS

Exposure to SHS significantly increased the risk for all-cause mortality and CVD. The risk associated with SHS exposure was large in China while the risk was only modest in the US. Studies using objectively measured SHS exposure may yield a higher risk of CVD than those using self-reported SHS exposure.

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

The aim of this updated statement is to provide comprehensive and timely evidence-based recommendations on the prevention of stroke among individuals who have not previously experienced a stroke or transient ischemic attack. Evidence-based recommendations are included for the control of risk factors, interventional approaches to atherosclerotic disease of the cervicocephalic circulation, and antithrombotic treatments for preventing thrombotic and thromboembolic stroke. Further recommendations are provided for genetic and pharmacogenetic testing and for the prevention of stroke in a variety of other specific circumstances, including sickle cell disease and patent foramen ovale.

Stroke mortality associated with environmental tobacco smoke among never-smoking Japanese women: a prospective cohort study

OBJECTIVE

This study examined the association of exposure to environmental tobacco smoke (ETS) during adulthood with stroke and its subtypes using data from a large-scale prospective cohort study in Japan.

METHODS

The study population included 36,021 never-smoking Japanese women who were enrolled between 1983 and 1985 and were followed-up for 15 years. We used Cox proportional hazard regression models to estimate hazard ratios (HRs) for stroke death associated with ETS exposure at home during adulthood.

RESULTS

A total of 906 cases of stroke death were observed during 437,715 person-years of follow-up. Compared with never-smoking women without smoking family members, HRs for stroke mortality among never-smoking women living with smoking family members in all subjects, in those aged 40-79 years, and in those aged ≥ 80 years were 1.14 (95% confidence interval: 0.99-1.31), 1.24 (95% CI: 1.05-1.46), and 0.89 (95% CI: 0.66-1.19), respectively, after adjustment for possible confounders. The risk was most evident for subarachnoid hemorrhage [HR: 1.66 (95% CI: 1.02-2.70) in all subjects].

CONCLUSION

This study suggests that exposure to ETS at home during adulthood is associated with an increased risk of stroke among never-smoking Japanese women.

Guidelines for the prevention of stroke in patients with stroke and transient ischemic attack: a guideline for healthcare professionals from the American Heart Association/American Stroke Association

The aim of this updated guideline is to provide comprehensive and timely evidence-based recommendations on the prevention of future stroke among survivors of ischemic stroke or transient ischemic attack. The guideline is addressed to all clinicians who manage secondary prevention for these patients. Evidence-based recommendations are provided for control of risk factors, intervention for vascular obstruction, antithrombotic therapy for cardioembolism, and antiplatelet therapy for noncardioembolic stroke. Recommendations are also provided for the prevention of recurrent stroke in a variety of specific circumstances, including aortic arch atherosclerosis, arterial dissection, patent foramen ovale, hyperhomocysteinemia, hypercoagulable states, antiphospholipid antibody syndrome, sickle cell disease, cerebral venous sinus thrombosis, and pregnancy. Special sections address use of antithrombotic and anticoagulation therapy after an intracranial hemorrhage and implementation of guidelines.

Secondhand smoke exposure predicted COPD and other tobacco-related mortality in a 17-year cohort study in China

BACKGROUND

Prospective evidence on the association between secondhand smoke (SHS) and COPD and ischemic stroke is scarce.

METHODS

We prospectively examined the relationship between SHS and major tobacco-related deaths, particularly COPD and stroke, in 910 Chinese (439 men, 471 women) who never smoked from a 17-year follow-up study in Xi’an, China. SHS exposure was defi ned as exposure to another person’s tobacco smoke at home or in the workplace.

RESULTS

At baseline among the 910 subjects, 44.2% were exposed to SHS at home, 52.9% in the workplace, and 67.1% at home, work, or both. From March 1, 1994, to July 1, 2011, 249 (150 men,99 women) died within 14,016 person-years. Those who were exposed to SHS had increased mortality due to coronary heart disease (adjusted relative risk [RR], 2.15; 95% CI, 1.00-4.61), ischemic stroke (RR, 2.88; 95% CI, 1.10-7.55), lung cancer (RR, 2.00; 95% CI, 0.62-6.40), COPD (RR, 2.30;95% CI, 1.06-5.00), and all causes (RR, 1.72; 95% CI, 1.29-2.20), with significant dose-response relationships between cumulative SHS exposure at home and work and the increased risk of cause-specific and total mortality (P for linear trend ranged from .045 to , .001).

CONCLUSIONS

This study shows dose-response relationships between SHS and major tobacco-related mortality and provides new evidence to support causation for COPD and ischemic stroke.

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.

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.

Smoking and stroke: the more you smoke the more you stroke

Cigarette smoking is a well-established risk factor for all forms of stroke. While both the general public and the global healthcare system are aware of the vascular risks associated with smoking, the prevalence of tobacco use has remained largely unchanged over the last quarter of a century. Approximately one in five US adults are classified as regular smokers, with the initiation of smoking typically occurring during the teenage years. Although the increased risk of stroke associated with smoking is generally acknowledged, it is less well recognized that considerable scientific evidence implicates a strong dose-response relationship between smoking and stroke risk. In this article, we summarize the literature regarding smoking-related stroke risk, the dose-response relationship, and the costs of this detrimental habit to both the individual and society as a whole.

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.

Lipid-soluble cigarette smoking particles induce expression of inflammatory and extracellular-matrix-related genes in rat cerebral arteries

AIMS

Cigarette smoking is one of the strongest risk factors for stroke. However, the underlying molecular mechanisms that smoke leads to the pathogenesis of stroke are incompletely understood.

METHODS

Dimethyl sulfoxide (DMSO)-soluble (lipid-soluble) cigarette smoking particles (DSP) were extracted from cigarette smoke (0.8 mg nicotine per cigarette; Marlboro). Rat cerebral arteries were isolated and organ cultured in the presence of DSP (0.2 microl/ml, equivalent to the plasma level in smokers) for 24 h. The expression of matrix metalloproteinase 9 and 13 (MMP9 and MMP13), angiotensin receptor 1 and 2 (AT(1) and AT(2)), interleukin 6 and inducible nitric oxide synthase (iNOS) were investigated at mRNA level by real-time PCR and/or at protein level by immunohistochemistry. In addition, the activity of three mitogen-activated protein kinases (p38, ERK 1/2 and SAPK/JNK) and their downstream transcription factors (ATF-2, Elk-1 and c-Jun) were examined.

RESULTS

We observed that compared with control (DMSO-treated cerebral arteries), the cerebral arteries treated by DSP exhibited enhanced expression of MMP13 and AT(1) receptors, but not of AT(2) receptors, at both mRNA and protein levels, suggesting that a transcriptional mechanism is most likely involved in the DSP effects. This is further supported by the findings that DSP induced phosphorylation of p38 mitogen-activated protein kinases inflammatory signal protein in parallel with activation of its downstream transcription factor ATF-2 and Elk-1. However, ERK 1/2 and SAPK/JNK activities were markedly expressed in the control (organ culture per se with DMSO), and DSP failed to further enhance the activation of ERK 1/2 and SAPK/JNK in the cerebral arteries.

CONCLUSIONS

DSP induces cerebral vessel inflammation with activation of p38 MAPK inflammatory signal and the downstream transcriptional factors (ATF-2 and Elk-1) in parallel with enhanced extracellular-matrix-related gene transcription and increased AT(1) receptor expression in the cerebral arteries, which are key events in stroke pathogenesis.

Spousal smoking and incidence of first stroke: the Health and Retirement Study

BACKGROUND

Few prospective studies have investigated the relationship between spousal cigarette smoking and the risk of incident stroke.

METHODS

Stroke-free participants in the U.S.-based Health and Retirement Study (HRS) aged >or=50 years and married at baseline (n=16,225) were followed, on average, 9.1 years between 1992 and 2006) for proxy or self-report of first stroke (1,130 events). Participants were stratified by gender and own smoking status (never-smokers, former smokers, or current smokers), and the relationship assessed between the spouse's smoking status and the risk of incident stroke. Analyses were conducted in 2007 with Cox proportional hazards models. All models were adjusted for age; race; Hispanic ethnicity; Southern birthstate; parental education; paternal occupation class; years of education; baseline income; baseline wealth; obesity; overweight; alcohol use; and diagnosed hypertension, diabetes, or heart disease.

RESULTS

Having a spouse who currently smoked was associated with an increased risk of first stroke among never-smokers (hazard ratio=1.42, 95% CI=1.05, 1.93) and former smokers (hazard ratio=1.72, 95% CI=1.33, 2.22). Former smokers married to current smokers had a stroke risk similar to respondents who themselves smoked.

CONCLUSIONS

Spousal smoking poses important stroke risks for never-smokers and former smokers. The health benefits of quitting smoking likely extend to both the individual smoker and his or her spouse.

Declines in hospital admissions for acute myocardial infarction in New York state after implementation of a comprehensive smoking ban

OBJECTIVES

Reductions in exposure to environmental tobacco smoke have been shown to attenuate the risk of cardiovascular disease. We examined whether the 2003 implementation of a comprehensive smoking ban in New York State was associated with reduced hospital admissions for acute myocardial infarction and stroke, beyond the effect of moderate, local and statewide smoking restrictions, and independent of secular trends.

METHODS

We analyzed trends in county-level, age-adjusted, monthly hospital admission rates for acute myocardial infarction and stroke from 1995 to 2004 to identify any association between admission rates and implementation of the smoking ban. We used regression models to adjust for the effects of pre-existing smoking restrictions, seasonal trends in admissions, differences across counties, and secular trends.

RESULTS

In 2004, there were 3813 fewer hospital admissions for acute myocardial infarction than would have been expected in the absence of the comprehensive smoking ban. Direct health care cost savings of $56 million were realized in 2004. There was no reduction in the number of admissions for stroke.

CONCLUSIONS

Hospital admission rates for acute myocardial infarction were reduced by 8% as a result of a comprehensive smoking ban in New York State after we controlled for other relevant factors. Comprehensive smoking bans constitute a simple, effective intervention to substantially improve the public's health.

Environmental vascular risk factors: new perspectives for stroke prevention

Despite intensive evaluation of acute stroke patients, perhaps only half of the attributable stroke risk is usually identified. In addition to traditional and non-traditional vascular risk factors-including most recently homocysteine, inflammation, and alterations of coagulation-a number of environmental risk factors for stroke have been identified in the last decade. In this update we review the following: lower education and poor socioeconomic status (probable surrogates for exposure to traditional high-risk behaviors such as smoking, poor nutrition, lack of prenatal control, absence of preventive medical and dental care, and non-compliance of treatment of conditions such as hypertension); depression, stress and affective disorders; obstructive sleep apnea; passive smoking and environmental pollution; infections, in particular periodontal diseases that increase C-reactive protein (CRP); raised body mass index (obesity); exercise, and diet. The possible role of high-fructose corn syrup in the epidemic of obesity in the USA is reviewed. Protective diets include higher consumption of fish, olive oil, grains, fruits and vegetables (Mediterranean diet), as well as probiotic bacteria in yogurt and dairy products. Careful attention should be given to the patient's environment looking for modifiable factors. The effects of clean environmental air and water, adequate diet and appropriate nutrition, healthy teeth, exercise, and refreshing sleep in the prevention of stroke and cardiovascular disease appear to be quite compelling. Although some of these modifiable risk factors lack evidence-based information, judicious clinical sense should be used to counteract the potentially damaging effects of adverse environmental vascular risk factors.

Environmental Tobacco Smoke Exposure and Risk of Stroke in Nonsmokers: A Review With Meta-analysis

Our objective was to provide a comprehensive review of the epidemiologic evidence relating stroke to exposure to environmental tobacco smoke (passive smoking) in lifelong nonsmokers. In all, 7 prospective, 6 case-control, and 3 cross-sectional studies were identified that provided relevant information. The 16 studies varied considerably in design, exposure indices used, and disease definition. Based on 24 sex-specific relative risk estimates, and using current spousal exposure (or nearest equivalent) as the exposure index, meta-analysis gave an overall estimate of 1.25 (95% confidence interval 1.16-1.36), with no significant heterogeneity. There was no significant heterogeneity by sex, year of publication, fatality, or disease end point. There was some indication that relative risks were less elevated in prospective studies and in US or European studies. No elevation was seen for subarachnoid hemorrhage. The estimate was similar using ever rather than current exposure, or total rather than spousal exposure. Adjustment for risk factors other than age had no material effect on the estimate. Eight studies provided dose-response estimates, the combined relative risk for the highest level of exposure being 1.56 (95% confidence interval 1.34-1.82). Many studies have evident weaknesses, and recall bias and particularly publication bias are major concerns. Currently, the association is only suggestive of a possible causal relationship. A clearer picture could be obtained using data from existing very large prospective studies that have already provided risk estimates for passive smoking and heart disease, and by conducting large, well-designed studies of incident stroke.

Dysphagia and Nutritional Status at the Time of Hospital Admission for Ischemic Stroke

BACKGROUND

Dysphagia and poor nutritional status occur frequently after stroke; however, potential associations between them are unknown. We evaluated potential associations between dysphagia and poor nutritional status in patients with acute ischemic stroke. Potential associations between these outcomes and more global stroke severity measures were also assessed.

METHODS

In all, 76 patients with acute ischemic stroke were recruited on admission to the dedicated stroke department of an academic medical center. All patients were assessed with a clinical swallowing evaluation, Functional Oral Intake Scale, Mini Nutritional Assessment, body mass index, percent body fat, National Institutes of Health Stroke Scale, modified Rankin Scale, and modified Barthel Index. Associations were evaluated among dysphagia, nutrition, and stroke severity measures.

RESULTS

On clinical examination 52.6% of study patients demonstrated dysphagia and 26.3% were identified with poor nutritional status. Dysphagia, based on clinical assessment, was associated with stroke severity (National Institutes of Health Stroke Scale, odds ratio [OR] 4.6, 95% confidence interval [CI] 1.6-13.1; modified Rankin Scale, OR 12.3, 95% CI 3.2-47.4) and with functional oral intake (OR 29.2, 95% CI 8.4-101.8), but not with measures of nutritional status (Mini Nutritional Assessment, OR 1.0, 95% CI 0.4-2.8). Nutritional measures did not correlate with swallowing or stroke severity measures.

CONCLUSIONS

Dysphagia and poor nutritional status are prevalent in patients with acute ischemic stroke, however, they are not associated with each other at the time of hospital admission. Furthermore, dysphagia, but not nutritional status, is associated with stroke severity measures.