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

Early-life tobacco smoke exposure and stroke risk: a prospective study of 341,783 and 352,737 UK Biobank participants

INTRODUCTION

Stroke is a life-threatening condition that causes a major medical burden globally. The currently used methods for the prevention or prediction of stroke have certain limitations. Exposure to tobacco in early life, including smoking during adolescence and maternal smoking during pregnancy, can affect adolescent development and lead to several negative outcomes. However, the association between early-life tobacco exposure and stroke is not known.

METHODS

In this prospective cohort study, for the analyses involving exposure to maternal smoking during pregnancy and age of smoking initiation, we included 304,984 and 342,893 participants, respectively., respectively from the UK Biobank. Cox proportional hazard regression model and subgroup analyses were performed to investigate the association between early-life tobacco exposure and stroke. Mediation analyses were performed to identify the mediating role of biological aging in the association between early tobacco exposure and stroke.

RESULTS

Compared with participants whose mothers did not smoke during pregnancy, participants whose mothers smoked during pregnancy showed an 11% increased risk of stroke (HR: 1.11, 95% CI: 1.05-1.18, P < 0.001). Compared with participants who never smoked, participants who smoked during adulthood, adolescence and childhood showed a 22%, 24%, and 38% increased risk of stroke during their adulthood, respectively. Mediation analysis indicated that early-life tobacco exposure can cause stroke by increasing biological aging.

CONCLUSION

This study reveals that exposure to tobacco during early life is associated with an increased risk of experiencing a stroke, and increased biological aging can be the underlying mechanism.

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.

Stroke Risk in Young Women with Primary Dysmenorrhea: A Propensity-Score-Matched Retrospective Cohort Study

BACKGROUND

Studies on strokes associated with dysmenorrhea are limited. We conducted a propensity-score-matched retrospective cohort study to assess the risk of stroke in women with primary dysmenorrhea (PD).

METHODS

From the claims data of one million people in Taiwan's insurance program, we identified 18,783 women aged 15-40 years, newly diagnosed with PD in 2000-2010, without a history of stroke. We randomly selected a comparison cohort without stroke history and dysmenorrhea, with the same sample size matched by age, index date, and propensity score. We began a follow-up with individuals one year after cohort entry to the end of 2013 to capture stroke events.

RESULTS

The two study cohorts were well-matched for age and comorbidities, with 54% of women aged 15-24. Stroke incidence was 1.5-fold higher in the PD cohort than in the comparison cohort (6.05 vs. 4.01 per 10,000 person-years, or 99 vs. 65 cases), with an adjusted hazard ratio (aHR) of 1.51 (95%CI 1.11-2.06) after adjustment for matched pairs. Nearly 70% of strokes were ischemic strokes, which occurred 1.6 times more frequently in the PD cohort than in the comparison cohort (4.40 vs. 2.71 per 10,000 person-years, or 72 vs. 44 cases), aHR = 1.61 (95% CI 1.11-2.33), after adjustment for matched pairs. The incidence of hemorrhagic stroke was also higher in the PD cohort than in the comparison cohort (1.65 vs. 1.29 per 10,000 person-years, or 27 versus 21 cases), but the difference was not significant.

CONCLUSION

Women of reproductive age with PD are at increased risk for ischemic stroke.

Secondhand smoke exposure is independently associated with stroke among non-smoking adults in West Africa

BACKGROUND

Stroke is a leading cause of disability and mortality worldwide, but little is known about the contribution of secondhand smoke exposure (SHSE) to stroke epidemiology among indigenous Africans.

OBJECTIVE

To evaluate the association of SHSE with stroke among indigenous Africans.

METHODS

We analyzed the relationship of SHSE with stroke among 2990 case-control pairs of adults who had never smoked (identified in the SIREN study) using conditional logistic regression at a two-sided P < 0.05.

RESULTS

Multivariable-adjusted odds ratio and 95% confidence interval; 1.25 (1.04, 1.50; P = 0.02) revealed SHSE was positively associated with stroke independent of stroke subtypes.

CONCLUSION

Culturally relevant primary prevention strategies targeted at SHSE might be promising in preventing stroke among Africans.

Comparison and determination of factors associated with smoking status, smoking knowledge, attitude and practice (S-KAP) between smoke-free and non-smoke-free campuses in public universities in Malaysia: a cross-sectional study

OBJECTIVES

We compared the smoking prevalence, smoking knowledge, attitudes and practices (S-KAP) between smoke-free campuses (SFCs) and non-SFCs (NSFCs) and determined the associated factors of smoking status and S-KAP.

DESIGN

Cross-sectional study.

SETTINGS

The research was conducted in four public universities in Malaysia; two SFCs and two NSFCs.

PARTICIPANTS

Students and staff from SFCs (n=1063) and NSFCs (n=1040).

MAIN OUTCOME MEASURES

Compared the smoking prevalence, S-KAP between SFCs and NSFCs and determined the associated factors.

RESULTS

The prevalence of smokers among the SFC and NSFC respondents was 5.2% and 6.7%, respectively. University type and smoking attitude were significantly related (p=0.02). At the SFCs, the factors associated with becoming a smoker were male gender (p<0.001), monthly income ≥RM3000 (p=0.02), positive smoking attitude (p=0.003) and positive smoking practice (p<0.001); at NSFCs, the associated factors were male gender (p<0.001), low smoking knowledge (p=0.004), positive smoking attitude (p=0.001) and practice (p<0.001). The factors associated with good smoking knowledge were female gender (SFCs: p=0.001; NSFCs: p=0.004), and monthly income ≥RM3000 (NSFCs: p=0.02). Male respondents were likely to have positive smoking attitudes (SFCs: p<0.001; NSFCs: p<0.001) and negative smoking practices (SFCs: p<0.001; NSFCs: p<0.001).

CONCLUSION

Overall, smoking prevalence, knowledge and practice were not much different between SFCs and NSFCs. However, there was a significant relationship between university type and smoking attitude due to the existence of the SFC policy likely rendering smoking a less acceptable social norm. Continual education programmes on smoking harms and smoking cessation strategies are highly recommended to aid the SFC policy in preventing secondhand smoke in universities.

Secondhand smoke exposure is associated with abnormal P-wave axis

OBJECTIVES

Secondhand smoke exposure (SHSE) is associated with increased risk of cerebrovascular accident (CVA). Abnormal P-wave axis (aPWA) is a marker for atriopathy that is also associated with CVA risk. We hypothesized that SHSE is associated with aPWA.

METHODS

This analysis included 5986 non-smokers (age 61.7 ± 13.8 years, 45.8% men, 77.4% Whites) from the Third National Health and Nutrition Examination Survey. SHSE was defined as serum cotinine ≥1 ng/ml aPWA was defined as any P-wave axis outside of 0-75°. Multivariable logistic regression was used to examine the association between SHSE and aPWA, overall and among subgroups stratified by demographics and comorbidities.

RESULTS

About 18.5% (n = 1109) of the participants had SHSE. aPWA was more prevalent among those with SHSE than those without (23.9% versus 19.8%, respectively, P-value = 0.003). In a model adjusted for sociodemographic and potential confounders, presence (versus absence) of SHSE was associated with increased odds of aPWA (odds ratio [95% confidence interval]: 1.28 [1.09, 1.50]; P-value = 0.003). This association was stronger among Whites vs non-Whites (interaction P-value = 0.04) and non-obese versus obese (interaction P-value = 0.04). Higher levels of serum cotinine were associated with increased odds of aPWA. Compared with serum cotinine level <1 ng/ml, serum cotinine ≥3 ng/ml and ≥6 ng/ml were associated with 35% (P-value = 0.002) and 38% (P-value = 0.002) increased odds of aPWA, respectively.

CONCLUSIONS

SHSE is associated with abnormal atrial conduction, measured as aPWA, with possible effect modification by ethnicity and obesity. These findings underscore the harmful effects of SHSE on cardiovascular health which merits a personalized risk assessment when counseling patients on SHSE.

Blood-Brain Barrier Transporters: Opportunities for Therapeutic Development in Ischemic Stroke

Globally, stroke is a leading cause of death and long-term disability. Over the past decades, several efforts have attempted to discover new drugs or repurpose existing therapeutics to promote post-stroke neurological recovery. Preclinical stroke studies have reported successes in identifying novel neuroprotective agents; however, none of these compounds have advanced beyond a phase III clinical trial. One reason for these failures is the lack of consideration of blood-brain barrier (BBB) transport mechanisms that can enable these drugs to achieve efficacious concentrations in ischemic brain tissue. Despite the knowledge that drugs with neuroprotective properties (i.e., statins, memantine, metformin) are substrates for endogenous BBB transporters, preclinical stroke research has not extensively studied the role of transporters in central nervous system (CNS) drug delivery. Here, we review current knowledge on specific BBB uptake transporters (i.e., organic anion transporting polypeptides (OATPs in humans; Oatps in rodents); organic cation transporters (OCTs in humans; Octs in rodents) that can be targeted for improved neuroprotective drug delivery. Additionally, we provide state-of-the-art perspectives on how transporter pharmacology can be integrated into preclinical stroke research. Specifically, we discuss the utility of in vivo stroke models to transporter studies and considerations (i.e., species selection, co-morbid conditions) that will optimize the translational success of stroke pharmacotherapeutic experiments.

[An overview of risk factors for stroke]

Stroke is a heterogeneous syndrome, and the definition of risk factors, treatment and prevention tactics depends on the specific pathogenesis of the disease. Risk factors for ischemic and hemorrhagic stroke are similar, but at the same time there are significant differences. The concept of stroke triggers is discussed separately. In addition, a deep understanding of the pathogenetic mechanisms and the development of new strategies for therapy and prevention require an understanding of the genetic mechanisms of stroke risk. Genetic factors may be more modifiable than previously thought. To reduce the burden of stroke in the population, timely identification and management of modifiable risk factors is essential.

Minority Women

Perceptions of illness, pain, and death are not static. They vary among populations according to their cultural and biological characteristics. Older black and Hispanic/Latinx women are unique in their approach to health care with respect to mentation, mobility, medication adherence, and what matters to them. It is the complexity of these components, which affect the ability of these women to age gracefully.

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.

Extension of Public Smoking Ban Was Not Associated with Any Immediate Effect on Stroke Occurrence in Finland

We investigated the association between the widening of a nationwide restaurant smoking ban, enacted on 1 June 2007, and stroke admissions. All acute stroke admissions between 1 May 2005 and 30 June 2009 were retrieved from a mandatory registry covering mainland Finland. Patients aged ≥18 years were included. One annual admission per patient was included. Negative binomial regression accounting for the at-risk population was applied. We found no difference in stroke occurrence before and after the smoking ban within 7 days (p = 0.217), 30 days (p = 0.176), or the whole study period (p = 0.998). Results were comparable for all stroke subtypes (ischemic stroke, intracerebral hemorrhage, and subarachnoid hemorrhage). There was no sign of decreased occurrence in June 2007 compared to June in 2005–2006, and all subtypes of stroke occurred at least as frequently in both May and June of 2008 as in May and June of 2007. In conclusion, the nationwide restaurant smoking ban Finland enacted in June 2007 was not associated with any immediate reduction in stroke occurrence.

Update on smoking. Alternatives for the management of patients with cardiovascular risk

Smoking is the leading cause of morbidity and mortality worldwide and is clearly involved as a cardiovascular risk factor. Smoking has different effects on the cardiovascular system, such as a decrease in nitric oxide, increased inflammatory response, increased adhesion of pro-atherogenic molecules, lipid disturbances, generation of oxidative stress and endothelial dysfunction as can be shown in different biomarkers modifications. Despite the aids currently available for smoking cessation, many smokers are unwilling or unable to achieve this. So alternative tools with potential harm reduction, such as non-combustion tobacco products, could be an option due to the better results they had shown on cardiovascular risk factors. This has led these devices to be taken into account as a risk-modifying tobacco product according to the FDA.

Heart Disease and Stroke Statistics-2021 Update: A Report From the American Heart Association

BACKGROUND

The American Heart Association, in conjunction with the National Institutes of Health, annually reports the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, diet, and weight) and health factors (cholesterol, blood pressure, and glucose control) that contribute to cardiovascular health. The Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, congenital heart disease, rhythm disorders, subclinical atherosclerosis, coronary heart disease, heart failure, valvular disease, venous disease, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The American Heart Association, through its Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States to provide the most current information available in the annual Statistical Update. The 2021 Statistical Update is the product of a full year's worth of effort by dedicated volunteer clinicians and scientists, committed government professionals, and American Heart Association staff members. This year's edition includes data on the monitoring and benefits of cardiovascular health in the population, an enhanced focus on social determinants of health, adverse pregnancy outcomes, vascular contributions to brain health, the global burden of cardiovascular disease, and further evidence-based approaches to changing behaviors related to cardiovascular disease.

RESULTS

Each of the 27 chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policy makers, media professionals, clinicians, health care administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

Tobacco Use: A Major Risk Factor of Intracerebral Hemorrhage

Spontaneous intracerebral hemorrhage (sICH) is one of the deadliest subtypes of stroke, and no treatment is currently available. One of the major risk factors is tobacco use. In this article, we review literature on how tobacco use affects the risk of sICH and also summarize the known effects of tobacco use on outcomes following sICH. Several studies demonstrate that the risk of sICH is higher in current cigarette smokers compared to non-smokers. The literature also establishes that cigarette smoking not only increases the risk of sICH but also increases hematoma growth, results in worse outcomes, and increases the risk of death from sICH. This review also discusses potential mechanisms activated by tobacco use which result in an increase in risk and severity of sICH. Exploring the underlying mechanisms may help alleviate the risk of sICH in tobacco users as well as may help better manage tobacco user sICH patients.

The Association between Secondhand Smoke and Stress, Depression, and Suicidal Ideation in Adolescents

Background: Secondhand smoke (SHS) is an important risk factor for adolescents’ health. Several studies have reported that SHS is as dangerous as active smoking. Therefore, this study aimed to investigate the association between exposure to SHS and mental health, including stress, depression, and suicidal ideation, in adolescents. Methods: Using raw data from the 2018 14th Korea Youth Risk Behavior Web-Based Survey, we analyzed the effects of sociodemographic characteristics on stress, depression, suicidal ideation in 51,500 students, including 85.8% of all sampled students (n = 60,040), after excluding students with a history of smoking, and then we performed logistic regression analysis to determine the level of exposure to SHS and its impact on stress, depression, and suicidal ideation. Results: The increased level of exposure to SHS was positively associated with stress, depression, and suicidal ideation. Furthermore, stress, depression, and suicidal ideation increased as the level of SHS increased, after adjusting for variables such as age, gender, education level of the father and mother, school achievement, economic status, inhabitation, and drinking. Conclusions: This study demonstrates that SHS is positively associated with risk of mental health problems, including stress, depression, and suicidal ideation, in adolescents. Further research and policy strategies and systems to prevent and manage exposure to SHS in adolescents are required.

Public knowledge of risk factors and warning signs for cardiovascular disease among young and middle-aged adults in rural Tanzania

Background

Improving cardiovascular health requires public knowledge and reduction of modifiable cardiovascular disease (CVD) risk factors. This study assessed knowledge of risk factors and warning signs for CVDs among young and middle-aged adults in Morogoro, Tanzania.

Methods

We conducted a community-based survey as part of cluster randomized controlled study of community health workers (CHWs) intervention for reduction of blood pressure among young and middle-aged adults in rural Morogoro. Information on socio-demographic characteristics, knowledge of risk factors and warning signs for CVDs was collected using an interviewer administered questionaire. Knowledge was assessed using open-ended questions followed by closed-ended questions. Descriptive statistics were used to describe knowledge of risk factors and warning signs. Logistic regression analysis was used to investigate factors associated with adequate knowledge of risk factors and warning signs for CVDs.

Results

Two-thirds (65.7%) of the participants had heard about CVDs. The main sources of information were mainly relatives/ neighbors (64.8%) and radio (53.0%). Only 28.3% of the participants reported health care providers as source of information about CVDs. More than half of the participants (52.4%) did not mention even one risk factor spontaneously while 55.2% were unable to mention any warning sign. When asked to select from a list, 6.9% were unable to correctly identify any risk factor whereas 11.8% could not correctly identify even a single warning sign. Quarter of participants (25.4%) had good knowledge score of risk factors, 17.5% had good knowledge score of warning signs and 16.3% had overall good knowledge of both risk factors and warning signs. Residing in Ulanga, having higher education level, having ever checked blood pressure and being overweight/obese predicted adequacy of knowledge score for both risk factors and warning signs.

Conclusion

Knowledge of risk factors and warning signs in this rural population of young and middle-aged adults was generally low. Health care providers were less likely to provide health education regarding risk factors and warning signs for CVDs. Health promotion interventions to increase population knowledge of risk factors and warning signs should be implemented for successful reduction of CVDs in Tanzania.

Impact of secondhand smoke exposure on cognitive function among middle-aged and older women in China: findings from three waves of the China Health and Retirement Longitudinal Study

OBJECTIVES

To examine the association between secondhand smoke (SSH) and women's global cognitive function and cognitive subdomains.

DESIGN

Cohort study.

PARTICIPANTS

Data for this study were obtained from the China Health and Retirement Longitudinal Study (2011-2013-2015), and pooled analysis was applied to wave 1 and wave 2 (2011-2013), wave 2 and wave 3 (2013-2015) and wave 1 and wave 3 (2011-2015). Data from a total of 6875 Chinese women with normal cognitive function at baseline were selected for analysis, including 2981 who were interviewed in 2011, 2471 in 2013, and 1894 in 2015.

MAIN OUTCOME MEASURES AND METHODS

SHS was classified based on the number of exposed years (<25 years, ≥25 years to <30 years, ≥30 years to <40 years, ≥40 years). Global cognitive function, visuospatial ability, orientation and attention, and episodic memory function were used as measures of cognitive function. Three waves of data were pooled using a dummy variable to differentiate between 2-year and 4-year groups. LDV models were used to examine independent associations between SHS and cognitive function. Demographic factors, socioeconomic factors, baseline cognitive functioning and health conditions were controlled for in our models.

RESULTS

SSH was found to be inversely and significantly associated with cognitive function. Compared with those who had not been exposed to household SSH, women who had lived with a smoking husband had a significantly faster cognition decline, especially in global cognitive function (β=-0.33, 95% CI=-0.66 to -0.01, p<0.01), visuospatial ability (β=-0.04, 95% CI=-0.08 to -0.01, p<0.05) and episodic memory function (β=-0.16, 95% CI=-0.31 to -0.01, p=0.031).

CONCLUSIONS

Household SSH exposure for more than 40 years was associated with a more significant decline in global cognitive function, visuospatial ability and episodic memory function, but not in orientation and attention function among older Chinese women.

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.

The moderating role of underlying predictors of survival in patients with brain stroke: a statistical modeling

Determining subclinical Brain stroke (BS) risk factors may allow for early and more operative BS prevention measures to find the main risk factors and moderating effects of survival in patients with BS. In this prospective study, a total of 332 patients were recruited from 2004 up to 2018. Cox's proportional hazard regressions were used to analyze the predictors of survival and the moderating effect by introducing the interaction effects. The survival probability 1-, 5- and 10-year death rates were 0.254, 0.053, and 0. 023, respectively. The most important risk factors for predicting BS were age category, sex, history of blood pressure, history of diabetes, history of hyperlipoproteinemia, oral contraceptive pill, hemorrhagic cerebrovascular accident. Interestingly, the age category and education level, smoking and using oral contraceptive pill moderates the relationship between the history of cerebrovascular accident, history of heart disease, and history of blood pressure with the hazard of BS, respectively. Instead of considerable advances in the treatment of the patient with BS, effective BS prevention remains the best means for dropping the BS load regarding the related factors found in this study.

Childhood Misfortune and Late-Life Stroke Incidence, 2004-2014

BACKGROUND AND OBJECTIVES

Although most strokes occur in later life, recent studies reveal that negative exposures decades earlier are associated with stroke risk. The purpose of this study was to examine whether accumulated and/or specific domains of early misfortune are related to stroke incidence in later life.

RESEARCH DESIGN AND METHODS

A decade of longitudinal data from stroke-free participants 50 years or older in the Health and Retirement Study were analyzed (N = 12,473). Incident stroke was defined as either self-reported first incident stroke or death due to stroke between 2004 and 2014.

RESULTS

Analyses revealed that accumulated misfortune was associated with increased stroke risk, but the relationship was moderated by wealth. Examining specific domains of childhood misfortune revealed that stroke incidence was greater for persons with behavioral/psychological risks, but that this relationship also was moderated by higher wealth for those with only one behavioral/psychological risk.

DISCUSSION AND IMPLICATIONS

Accumulated childhood misfortune and adolescent depression heighten the risk of stroke in later life, but the influence is remediable through adult wealth. Reducing poverty in later life may decrease stroke incidence for persons exposed to negative childhood exposures.

Dose-related effect of secondhand smoke on cardiovascular disease in nonsmokers: Systematic review and meta-analysis

BACKGROUND

Despite the positive association between secondhand smoke (SHS) and cardiovascular diseases (CVD), no comprehensive assessment on the dose-response relationship between SHS and CVD has yet been reported. Therefore, a meta-analysis was conducted to update the binary association, and to elucidate the dose-response relationship of both self-reported and objectively measured SHS exposure with CVD.

METHODS

PubMed and Embase databases were searched for articles published up to November 12, 2019. Random-effects models were used to assess the summary odds ratios (ORs) of CVD with SHS exposure. Restricted cubic splines were used to fit the dose-response relationship.

RESULTS

Fifty-five eligible observational studies were included in this meta-analysis to investigate the association between SHS exposure and CVD. Based on the meta-analysis, the pooled OR of CVD was 1.22 (95% CI 1.17-1.28) for the self-reported SHS individuals as comparing to the non-exposed group. The result of restricted cubic splines showed a risk plateau of SHS exposure at 15 cigarettes per day (P_{non-linearity} = 0.042), while other characteristics s of SHS exposure (amount, daily and cumulative duration, and cotinine) were in linear relationships with CVD (P_{non-linearity} >0.05). In addition, an estimated of 6.77% (95% CI: 5.31%-8.46%) of all CVD cases in men and 7.15% (95% CI: 5.62%-8.93%) in women might be attributed to SHS exposure worldwide.

CONCLUSIONS

Exposure to SHS is associated with an increased risk of CVD regardless of the modes. And thus, well-enforced smoke-free laws could possibly reduce a substantial risk of CVD caused by SHS.

Second-Hand Smoke Exposure Among Coronary Heart Disease Patients

Purpose

The objectives of this study were to assess second-hand smoke (SHS) exposure among coronary heart disease (CHD) patients at home, in transportation, workplace, public and social places; to examine the demographic factors that predict SHS exposure; and to investigate the relationship between SHS exposure and CHD complications, age at the time of diagnosis, and number of admissions in the last year.

Patients and Methods

A descriptive cross-sectional design was used with a convenient sample of 400 CHD patients from three hospitals in Jordan. A modified version of the Smoking Scale for Adults (SS-A) was used.

Results

The percentage of SHS exposure was 64% in public places, 51.5% in social places, 48.5% in the household, 31% in transportation, while it was only 14.8% in the workplace. In addition, being male, employed, having a younger age and lower education significantly predicted higher exposure to SHS. Exposure to SHS was positively associated with CHD complications and the number of admissions, while it was negatively associated with the age at diagnosis with CHD.

Conclusion

Collaboration is needed among all health care sectors to adopt educational strategies about SHS exposure and to activate policies to prohibit smoking in public places.

Heart Disease and Stroke Statistics-2020 Update: A Report From the American Heart Association

BACKGROUND

The American Heart Association, in conjunction with the National Institutes of Health, annually reports on the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, diet, and weight) and health factors (cholesterol, blood pressure, and glucose control) that contribute to cardiovascular health. The Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, congenital heart disease, rhythm disorders, subclinical atherosclerosis, coronary heart disease, heart failure, valvular disease, venous disease, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The American Heart Association, through its Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States to provide the most current information available in the annual Statistical Update. The 2020 Statistical Update is the product of a full year's worth of effort by dedicated volunteer clinicians and scientists, committed government professionals, and American Heart Association staff members. This year's edition includes data on the monitoring and benefits of cardiovascular health in the population, metrics to assess and monitor healthy diets, an enhanced focus on social determinants of health, a focus on the global burden of cardiovascular disease, and further evidence-based approaches to changing behaviors, implementation strategies, and implications of the American Heart Association's 2020 Impact Goals.

RESULTS

Each of the 26 chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policy makers, media professionals, clinicians, healthcare administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

Telomere Length: A Potential Biomarker for the Risk and Prognosis of Stroke

Stroke is one of the leading causes of death and disability worldwide. Age is associated with increased risk of stroke, while telomere length shortening plays a pivotal role in the process of aging. Moreover, telomere length shortening is associated with many risk factors of stroke in addition to age. Accumulated evidence shows that short leukocyte telomere length is not only associated with stroke occurrence but also associated with post-stroke recovery in the elderly population. In this review, we aimed to summarize the association between leukocyte telomere length and stroke, and discuss that telomere length might serve as a potential biomarker to predict the risk and prognosis of stroke.

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.

Stroke in the elderly

Stroke remains the second leading cause of death in the world, and its prevalence is projected to rise in the United States and globally. The main driver for increased stroke prevalence is aging of the population; however, best evidenced-based strategies for stroke treatment and prevention are not always followed for older patients. Furthermore, considerable gaps in knowledge exist for stroke prevention and treatment in elderly and very elderly patients. In this chapter, we discuss various aspects of stroke care in the elderly, including the evidence that guides stroke prevention and treatment. We focus on the challenges in managing stroke in the very elderly including the paucity of data to guide management. The sections span the continuum of stroke care, from primary prevention to management of stroke complications. Finally, we highlight the most significant unanswered questions regarding stroke care in the elderly.

The toxicology of air pollution predicts its epidemiology

The epidemiologic investigation has successively delineated associations of air pollution exposure with non-malignant and malignant lung disease, cardiovascular disease, cerebrovascular disease, pregnancy outcomes, perinatal effects and other extra-pulmonary disease including diabetes. Defining these relationships between air pollution exposure and human health closely parallels results of an earlier epidemiologic investigation into cigarette smoking and environmental tobacco smoke (ETS), two other particle-related exposures. Humic-like substances (HULIS) have been identified as a chemical component common to cigarette smoke and air pollution particles. Toxicology studies provide evidence that a disruption of iron homeostasis with sequestration of host metal by HULIS is a fundamental mechanistic pathway through which biological effects are initiated by cigarette smoke and air pollution particles. As a result of a common chemical component and a shared mechanistic pathway, it should be possible to extrapolate from the epidemiology of cigarette smoking and ETS to predict associations of air pollution exposure with human disease, which are currently unrecognized. Accordingly, it is anticipated that the forthcoming epidemiologic investigation will demonstrate relationships of air pollution with COPD causation, peripheral vascular disease, hypertension, renal disease, digestive disease, loss of bone mass/risk of fractures, dental disease, eye disease, fertility problems, and extrapulmonary malignancies.

Health and Healthcare Needs of Koreans in San Francisco Bay Area: The Korean Needs Assessment (KoNA) Project

Korean Americans (KA) face a significant burden of health disparities. However, limited data are available on their health needs. This health needs assessment includes a community-based sample of 342 KA from the San Francisco Bay Area. The assessment investigated participants' sociodemographic characteristics, health status, and their healthcare needs. Nearly half of the survey participants rated their health as fair or poor, > 30% did not have a usual place for healthcare, and chronic conditions were prevalent. Limited English Proficiency (LEP) was significantly associated with low self-rated health and having no usual source of care, after adjusting for other sociodemographic factors. Older, LEP KA faced the highest health and health care burden. In addition, females were less likely to be physically active. Males were more likely to smoke. The findings provide guidance in identifying major KA health needs and supports local programming and policy development for KA.

Association between serum cotinine levels and electrocardiographic left atrial abnormality

BACKGROUND

Although the harmful effect of tobacco exposure on cardiovascular disease (CVD) and its risk factors are well established, the constituents of cigarette-smoke and the pathophysiological mechanism involved are unknown. Recently, deep terminal negativity of P wave in V1 (DTNPV1) has emerged as a marker of left atrial abnormality that predicts atrial fibrillation, stroke, and death due to all-cause or CVD. Therefore, we examined the association between serum cotinine levels with abnormal DTNPV1 using the Third National Health and Nutrition Examination Survey.

METHODS

This analysis included 4,507 participants (mean age 58 ± 13 years, 53% women, 49% non-Hispanic white) of NHANES III, without history of CVD or major electrocardiographic abnormalities and not on heart rate modifying medications. Multivariable logistic regression analysis was used to examine the association between serum cotinine and abnormal DTNPV1-defined from automatically processed electrocardiograms as values of the amplitude of the terminal negative phase of P wave in lead V1 exceeding 100 μV.

RESULTS

Abnormal DTNPV1 was detected in 2.3% (n = 105) of the participants. In a model adjusted for demographics and CVD risk factors, each 10 ng/ml serum cotinine was associated with 2% increased odds of abnormal DTNPV1 (odds ratio 1.02, 95% confidence interval 1.01-1.03, p-value < 0.001). This association was consistent in subgroups stratified by age, sex, race, smoking status, hypertension, diabetes, dyslipidemia, and chronic obstructive pulmonary disease.

CONCLUSION

Elevated serum cotinine levels are associated with an abnormal DTNPV1. This suggests that nicotine exposure can lead to left atrial abnormalities, a possible mechanism for increased risk of CVD.

Awareness of health effects of exposure to secondhand smoke from cigarettes: A cross-sectional study of never-smoked adult primary care patients in Eastern Nigeria

Background:

Cigarette smoking whether actively or passively is a growing public health problem. Despite the wealth of information on the hazards of active cigarette smoking, awareness of the health effects of passive smoking on human population is often neglected in Nigeria.

Aim:

The study was aimed at describing the awareness of health effects of exposure to secondhand smoke from cigarettes among never-smoked adult primary care patients in Eastern Nigeria.

Materials and Methods:

A hospital-based study carried out on a cross-section of 500 adult patients in a primary care clinic in Nigeria. Data were collected using pretested, structured, and interviewer-administered questionnaire. Exposure to secondhand smoke was defined as exposure to cigarette smoke in a never-smoked adult patient in the previous 1 year. Data were analyzed using Statistical Package for Social Sciences version 21 for the calculation of percentages for categorical variables. Bivariate analysis involving Chi-square test was used to test for significance of association between categorical variables at P < 0.05.

Results:

The age of the respondents ranged from 18 to 74 years, with a mean age of 36 ± 12.4 years. There were 180 (36.0%) males with 320 (64%) females, with a sex ratio of 1.8. Awareness of general health effects of secondhand smoke on adults, children, and pregnant women was 95.6%, 92.8%, and 65.2%, respectively. The most common specific health effects the respondents were aware for adults, children, and obstetric population were lung cancer (95.6%), precipitation of asthmatic condition (92.8%), and delivery of small babies (65.2%), respectively. The predominant source of awareness of information was radio (93.6%). Awareness of general health effects of exposure to secondhand smoke on adults (P = 0.041), children (P = 0.031), and obstetrics population (P = 0.02) was significantly associated with exposure status.

Conclusion:

The most common health effects of secondhand smoke the respondents had highest awareness were lung cancer, precipitation of asthmatic attacks, and delivery of small babies in adults, children, and obstetric population, respectively. Awareness of general health effects on adults, children, and obstetrics population was significantly associated with exposure status. The current level of awareness should be improved while effort should be intensified to address identified areas of low level of awareness.

Environmental Tobacco Smoke Exposure and Smoke-Free Rules in Homes among Socially-Disadvantaged Populations in Poland

This study aims to examine the prevalence of exposure to environmental tobacco smoke (ETS) in homes among socially-disadvantaged populations in Poland, along with the prevalence and correlates of voluntary implementation of smoke-free home rules. Data concerning 1617 respondents from a cross-sectional study completed in the Piotrkowski District were used, which was part of the "Reducing Social Inequalities in Health" program. Overall, 19.4% of the respondents declared exposure to ETS at home. In the non-smokers group, 15.5%, including 6.6% males and 18.3% females, were exposed to ETS in their place of residence (p < 0.0001). Complete smoke-free rules were adopted by 22.1% of the study participants. Two factors, smoker status and lack of ETS-associated health risk awareness, were found to be significantly associated with no adoption of total smoking bans at home. Socially-disadvantaged non-smokers, especially females from rural areas in Poland, still constitute a large population exposed to ETS in their homes-a challenge from the perspective of public health. Focused efforts are required to address social norms around exposing others to ETS.

Ambient PM2.5 and Stroke: Effect Modifiers and Population Attributable Risk in Six Low- and Middle-Income Countries

BACKGROUND AND PURPOSE

Short-term exposure to ambient fine particulate pollution (PM_2.5) has been linked to increased stroke. Few studies, however, have examined the effects of long-term exposure.

METHODS

A total of 45 625 participants were interviewed and included in this study, the participants came from the Study on Global Ageing and Adult Health, a prospective cohort in 6 low- and middle-income countries. Ambient PM_2.5 levels were estimated for participants' communities using satellite data. A multilevel logistic regression model was used to examine the association between long-term PM_2.5 exposure and stroke. Potential effect modification by physical activity and consumption of fruit and vegetables was assessed.

RESULTS

The odds of stroke were 1.13 (95% confidence interval, 1.04-1.22) for each 10 μg/m³ increase in PM_2.5. This effect remained after adjustment for confounding factors including age, sex, smoking, and indoor air pollution (adjusted odds ratio=1.12; 95% confidence interval, 1.04-1.21). Further stratified analyses suggested that participants with higher levels of physical activity had greater odds of stroke, whereas those with higher consumption of fruit and vegetables had lower odds of stroke. These effects remained robust in sensitivity analyses. We further estimated that 6.55% (95% confidence interval, 1.97%-12.01%) of the stroke cases could be attributable to ambient PM_2.5 in the study population.

CONCLUSIONS

This study suggests that ambient PM_2.5 may increase the risk of stroke and may be responsible for the astounding stroke burden in low- and middle-income countries. In addition, greater physical activity may enhance, whereas greater consumption of fruit and vegetables may mitigate the effect.

Stroke Risk Factors, Genetics, and Prevention

Stroke is a heterogeneous syndrome, and determining risk factors and treatment depends on the specific pathogenesis of stroke. Risk factors for stroke can be categorized as modifiable and nonmodifiable. Age, sex, and race/ethnicity are nonmodifiable risk factors for both ischemic and hemorrhagic stroke, while hypertension, smoking, diet, and physical inactivity are among some of the more commonly reported modifiable risk factors. More recently described risk factors and triggers of stroke include inflammatory disorders, infection, pollution, and cardiac atrial disorders independent of atrial fibrillation. Single-gene disorders may cause rare, hereditary disorders for which stroke is a primary manifestation. Recent research also suggests that common and rare genetic polymorphisms can influence risk of more common causes of stroke, due to both other risk factors and specific stroke mechanisms, such as atrial fibrillation. Genetic factors, particularly those with environmental interactions, may be more modifiable than previously recognized. Stroke prevention has generally focused on modifiable risk factors. Lifestyle and behavioral modification, such as dietary changes or smoking cessation, not only reduces stroke risk, but also reduces the risk of other cardiovascular diseases. Other prevention strategies include identifying and treating medical conditions, such as hypertension and diabetes, that increase stroke risk. Recent research into risk factors and genetics of stroke has not only identified those at risk for stroke but also identified ways to target at-risk populations for stroke prevention.

Association of Secondhand Smoke With Stroke Outcomes

Background and Purpose—

Approximately half of never smokers are exposed to secondhand smoke (SHS). Smoking is a well-established stroke risk factor, yet associations between SHS, stroke, and poststroke mortality remain uncertain. We aimed to determine the prevalence of exposure to SHS among those with and without stroke and its impact on mortality.

Methods—

Data were obtained from the US National Health and Nutrition Examination Surveys for 27 836 never smokers with/without self-reported stroke aged ≥18 years, sampled from 1988 to 1994 and 1999 to 2012, with linked mortality through 2010. Household exposure to SHS was determined by self-report; exposure severity was quantified by serum cotinine level. Independent relationships between SHS and all-cause mortality were assessed using Cox regression models, before and after adjusting for sociodemographics and comorbidities.

Results—

From 1988 to 1994 to 1999 to 2012, age-adjusted prevalence of exposure to SHS declined from 11.5% to 6.6% among survivors of stroke ( P =0.08), and 14.6% to 5.9% among persons without stroke ( P <0.01). Factors associated with high exposure to SHS were male sex, black race, ≤12th-grade education, poverty income ratio ≤200%, high alcohol intake, and history of myocardial infarction (all P <0.05). High exposure to SHS was associated with higher odds of previous stroke (odds ratio, 1.46; P =0.026). There was a dose-dependent relationship between exposure to SHS and all-cause mortality after stroke.

Conclusions—

Individuals with previous stroke have 50% greater odds to have been exposed to SHS; SHS is associated with a 2-fold increase in mortality after stroke. This study highlights the importance of obtaining exposure to SHS history and counseling patients and their families on the potential impact of SHS on poststroke outcomes.

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.