Case-control study of passive smoking at home and risk of acute myocardial infarction. Argentine FRICAS Investigators. Factores de Riesgo Coronario en América del Sur

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.

Effects of passive smoking on severe nausea and vomiting of pregnancy among urban Chinese nonsmoking women

Background

Nausea and vomiting of pregnancy (NVP) is one of the most common pregnancy-associated symptoms, but little is known about the effects of passive smoking on this symptom. Passive smoking among women is widespread and severe in China due to the high proportion of men who smoke actively. The aim of this study is to examine the association between maternal passive smoking and severe NVP in early pregnancy among nonsmoking women in urban China.

Methods

We collected information on passive smoking status and severe NVP in early pregnancy based on an ongoing prospective cohort study conducted from October 2017 to May 2019 in Beijing, China. We used multivariable logistic model to calculate adjusted odds ratios (ORs) and 95% confidence intervals (95% CIs) after controlling for confounding factors.

Results

Among 3064 participants who were involved in the final analysis, 7.4% (n = 227) were passive smokers and 9.8% (n = 299) reported severe NVP. After adjusting for potential confounders, passive smoking conferred an increased risk of NVP (adjusted OR = 1.62, 95% CI: 1.08, 2.43). The frequency of exposure to second-hand smoke showed a positive relationship with the risk of severe NVP, and significant subgroup differences were also observed in stratified analyses by parity and education level.

Conclusions

Our results suggested that maternal exposure to second-hand smoke remained to be a major public health problem in urban China, and that passive smoking during the first trimester may increase the risk of severe NVP among nonsmoking pregnant women. Measures should be taken to reduce the impact of second-hand smoke exposure on pregnant 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.

Steps Toward Scalability: Illustrations From a Smoke-Free Homes Program

Scalable interventions remain effective across a range of real-world settings and can be modified to fit organizational and community context. "Smoke-Free Homes: Some Things are Better Outside" has been effective in promoting smoke-free home rules in low-income households in efficacy, effectiveness, generalizability, and dissemination studies. Using data from a dissemination study in collaboration with five 2-1-1 call centers in Ohio, Florida, Oklahoma, and Alabama (n = 2,345 households), this article examines key dimensions of scalability, including effectiveness by subpopulation, secondary outcomes, identification of core elements driving effectiveness, and cost-effectiveness. Evaluated by 2-1-1 staff using a pre-post design with self-reported outcomes at 2 months postbaseline, the program was equally effective for men and women, across education levels, with varying number of smokers in the home, and whether children were present in the home or not. It was more effective for nonsmokers, those who smoked fewer cigarettes per day, and African Americans. Creating a smoke-free home was associated with a new smoke-free vehicle rule (odds ratio [OR] = 3.38, confidence interval [CI 2.58, 4.42]), decreased exposure to secondhand smoke among nonsmokers (b = -2.33, p < .0001), and increased cessation among smokers (OR = 5.8, CI [3.81, 8.81]). Use of each program component was significantly associated with success in creating a smoke-free home. Using an intent-to-treat effect size of 40.1%, program benefits from 5 years of health care savings exceed program costs yielding a net savings of $9,633 for delivery to 100 households. Cost effectiveness, subpopulation analyses, and identification of core elements can help in assessing the scalability potential of research-tested interventions such as this smoke-free homes program.

Effects of smoke-free air law on acute myocardial infarction hospitalization in Indianapolis and Marion County, Indiana

BACKGROUND

A comprehensive smoke-free air law was enacted on June 1, 2012 in most of Marion County, Indiana, including all of the City of Indianapolis. We evaluated changes in acute myocardial infarction (AMI) admission rates in Indianapolis and Marion County before compared to after the law.

METHODS

We collected AMI admissions from five Marion County hospitals between May 2007 and December 2014. We used Poisson regression to evaluate the overall effects of the law on monthly AMI hospitalizations, adjusting for month, seasonality, meteorology, air pollution, and hospital utilization. We tested the interactions between the law and AMI risk factors on monthly AMI admission rates to identify subpopulations for which the effects might be stronger.

RESULTS

Monthly AMI admissions declined 20% (95% CI 14-25%) in Marion County and 25% (95% CI 20-29%) in Indianapolis after the law was implemented. We observed decreases among never (21%, 95% CI 13-29%), former (28%, 95% CI 21-34%), and current smokers (26%, 95% CI 11-38%); Medicaid beneficiaries (19%, 95% CI 9-29%) and non-beneficiaries (26%, 95% CI 20-31%). We observed decreases among those with a history of diabetes (Yes: 22%, 95% CI 14-29%; No: 25%, 95% CI 18-31%), congestive heart failure (Yes: 23%, 95% CI 16-30%; No: 24%, 95% CI 17-31%), and hypertension (Yes: 23%, 95% CI 17-28%: No: 26%, 95% CI 15-36%).

CONCLUSIONS

We observed decreases in AMI admissions comparable with previous studies. We identified subpopulations who benefitted from the law, such as former and current smokers, and those without comorbidities such as congestive heart failure and hypertension.

The impact of passive and active smoking on inflammation, lipid profile and the risk of myocardial infarction

Objective

To investigate the effect of passive smoking, active smoking and smoking cessation on inflammation, lipid profile and the risk of myocardial infarction (MI).

Methods

A total of 423 cases with a first MI and 465 population controls from the Maltese Acute Myocardial Infarction (MAMI) Study were analysed. Data were collected through an interviewer-led questionnaire, and morning fasting blood samples were obtained. ORs adjusted for the conventional risk factors of MI (aORs) were calculated as an estimate of the relative risk of MI. The influence of smoking on biochemical parameters was determined among controls.

Results

Current smokers had a 2.7-fold (95% CI 1.7 to 4.2) and ex-smokers a 1.6-fold (95% CI 1.0 to 2.4) increased risk of MI. Risk increased with increasing pack-years and was accompanied by an increase in high-sensitivity C reactive protein levels and an abnormal lipid profile. Smoking cessation was associated with lower triglyceride levels. Exposure to passive smoking increased the risk of MI (aOR 3.2 (95% CI 1.7 to 6.3)), with the OR being higher for individuals exposed to passive smoking in a home rather than in a public setting (aOR 2.0 (95% CI 0.7 to 5.6) vs aOR 1.2 (95% CI 0.7 to 2.0)). Passive smoke exposure was associated with higher levels of total cholesterol, triglycerides and total cholesterol:high-density lipoprotein cholesterol ratio compared with individuals not exposed to passive smoking.

Conclusions

Both active and passive smoking are strong risk factors for MI. This risk increased with increasing pack-years and decreased with smoking cessation. Such effects may be partly mediated through the influence of smoking on inflammation and lipid metabolism.

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.

Effects of passive smoking on hypertension in rural Chinese nonsmoking women

BACKGROUND

Increasing evidence suggest that active smoking is a risk factor for hypertension, but little is known about the effects of passive smoking on this condition. In China, female passive smoking is widespread and severe due to the high proportion of men who smoke, particularly in rural areas. This study assessed whether passive smoking is associated with increased risk of hypertension among nonsmoking women in rural China.

METHODS

A total of 392 nonsmoking women from a rural area of Shanxi Province (northern China) participated in this cross-sectional study. Data on female passive smoking, and other factors known to influence hypertension, were collected during face-to-face interviews. Logistic regression was used to evaluate the association analyses after adjusting for potential confounders.

RESULTS

In total, 162 of the 392 participants were hypertensive (41.3%); 118 participants (30.1%) reported exposure to passive smoking, of whom 88.4% were exposed to smoke in the home. After adjusting for age, BMI, education, occupation, drinking status, physical activity, and menopause status, passive smoking conferred an approximately two-fold risk increase of hypertension (adjusted odds ratio = 1.99, 95% confidence interval 1.16, 3.39). The adjusted odds ratios for passive smoking exposure levels of one to three, four to six, and more than six occasions per week were 1.01 (0.39-2.62), 2.57 (1.05-6.30), and 2.59 (1.18-5.69), respectively.

CONCLUSION

In rural areas of northern China, female passive smoking in the home is prevalent. Frequent exposure to secondhand smoke is a risk factor for hypertension among nonsmoking women, which suggests that measures should be taken to prevent passive smoking among this population.

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.

Association between second-hand smoking and acute coronary heart disease among Arab women with multiple risk factors

BACKGROUND

Active smoking is a well-established risk factor for coronary heart disease (CHD). However, the role of second-hand smoking (SHS) needs further investigation. We aimed to study the association between SHS and CHD in Arab women in Israel.

METHODS

A matched case-control study among non-smoking Arab women. The case group included women discharged from hospital after having acute coronary event. The control group was women without CHD who were individually matched for age and type-2 diabetes. The women were interviewed with structured questionnaires on exposure to SHS and on attitudes towards such exposure, and underwent anthropometric measurements.

RESULTS

A total of 146 women were included, the majority had type-2 diabetes (68.5%) and were overweight or obese (89.4% of cases and 93.2% of controls, P = 0.727). The prevalence of exposure to domestic-SHS after marriage was higher among the cases than controls (91.8% vs. 53.4%, P < 0.001). After adjustment for hypertension, body mass index > 25 and family history, exposure to domestic-SHS after marriage was an independent risk factor for CHD (OR = 6.1, 95% CI 1.93-19.3). Compared with no exposure, the exposed for 2-6 h a day had an OR of 5.68 (1.48-21.73), and for >6 h a day the OR reached 26.12 (4.26-159.92). Women with CHD felt less comfortable voicing their concern about smoking near them and more highly agreed with prohibition of smoking.

CONCLUSIONS

Exposure to domestic-SHS is independently associated with CHD in Arab women, with a strong dose-response relationship, emphasizing the need for public health initiatives to reduce exposure to domestic-SHS.

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.

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

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

Work-related risk factors of myocardial infarction

OBJECTIVES

The aim of the study was to find out which occupational factors account for the risk of the myocardial infarction.

MATERIAL AND METHODS

A questionnaire survey was performed during the period of one calendar year in all patients (1053 subjects, 692 men and 361 women) hospitalized at the Medical University of Łódź because of the first myocardial infarction. The questionnaire was prepared especially for the purpose of this study and consisted of two parts. The first part comprised: demographic data, health status at admittance, traditional risk factors for the ischaemic heart disease and was filled-in by physicians. Part II was done by occupational hygiene specialists and referred to education, job title and characteristics, employment data, self assessment of work-related and general stress, fatigue, socio-economic status, physical activity, alcohol intake, tobacco smoking, dietary habits.

RESULTS

Mean age in the study group was 59.9 ± 10.4 years (26-85 years), 58.7 ± 10.0 (26-84 years) for men and 62.3 ± 10.7 (32-85 years) for women, employment duration was 32.9±8.8 (4-65 years), for men 34.0 ± 8.6 (5-65 years), for women 30.7 ± 8.8 (4-60 years. Most of myocardial infarction cases both in the group of men and women were noted in the age interval 56-60 years, 22.3% vs. 17.4%, respectively. The majority of examined men were farmers, low and middle management and self-employed workers. Among women prevailed clerks, seamstresses and farmers. The most frequent occupational risk factors were: work-related stress, experienced by 54.2% of the examined subjects, occupational noise (45,5%), dust (41,7%) and various chemical factors (33%). A majority of the study group (76.5% women and 54.4% men) linked the cardiac infarction with stress, while 39.1% men vs. 16.5% women correlated it with physical effort.

CONCLUSION

Our studies indicate that, among a wide spectrum of occupational factors, stress, noise and fine particulate dust are major contributors to the increased risk of myocardial infarction.

Cardiovascular disease in Latin American women

Cardiovascular disease is a leading cause of death and disability in adults in Latin America. Women are more affected by these diseases than by all forms of cancer. Latin American countries have experienced rapid and uneven socioeconomic changes with a significant effect on lifestyle, demographic and health-related indicators. Differences in methodological approaches make it difficult to compare studies and health statistics across countries in the region. According to available statistics, female population in Latin American countries have lower mortality rate from coronary heart disease and higher mortality rate from cerebrovascular disease than North America. Current rates of obesity and type 2 diabetes are alarming in female in some countries. The high prevalence of risk factors forecasts an increase in cardiovascular disease for the coming decades in this region of the world. More systematic and sustained efforts for research, education, surveillance, prevention, early detection and affordable treatment are required across all Latin American countries to improve health conditions for adult population and particularly for women, who are more affected by obesity and diabetes. This article reviews the available information on cardiovascular disease and related risk factors in Latin American countries with a focus on female and to provide a brief description of selected multinational and national efforts to study and prevent this threat.

Association of cigarette smoking with albuminuria in the United States: the third National Health and Nutrition Examination Survey

BACKGROUND

The association of cigarette smoking with albuminuria has been reported but not examined in a representative U.S. population. No study has evaluated the association between serum cotinine (a biological marker for tobacco exposure) and kidney damage.

METHODS

A cross-sectional analysis was conducted among 15,719 adult participants of the third National Health and Nutrition Examination Survey to assess the association between smoking exposure and kidney damage. Smoking was assessed by self-reported lifetime cigarette use and serum cotinine. Kidney damage was assessed by urine albumin-to-creatinine ratio (ACR), with albuminuria defined as ACR of > or =17 microg/mg in males and > or =25 microg/mg in females.

RESULTS

The analysis included 13,121 with normal albumin (mean ACR 6.3 microg/mg) and 2,414 with albuminuria (mean ACR 143 microg/mg); hypertension was prevalent in 27% and 59%, respectively. Former smoking was similar between groups (21%), while current smoking was more common in persons with albuminuria (26%) compared to normal ACR (21%). Adjusted for other risk factors, among hypertensives, current smokers were 1.85 (95% CI: 1.29, 2.64) times more likely to have albuminuria than never smokers. Current smokers with a > or =40 pack-year history were at highest risk for albuminuria. Among non-smoking hypertensives, those exposed to passive smoke (highest versus lowest quartile of serum cotinine) were 1.41 (95% CI: 1.04, 1.90) times more likely to have albuminuria. Former smoking with cessation of > or =1 year among hypertensives was not associated with albuminuria. Among non-hypertensives, smoking and albuminuria were not consistently associated.

CONCLUSION

Current and passive smoking, but not former smoking, were associated with the presence of albuminuria in the general U.S. population with hypertension, indicating a benefit to the kidney from smoking cessation.

Analysis and evaluation of environmental tobacco smoke exposure as a risk factor for chronic cough

Exposure to environmental tobacco smoke (ETS) and active tobacco smoking has been shown to increase symptoms of bronchial asthma such as bronchoconstriction but effects on other respiratory symptoms remain poorly assessed. Current levels of exposure to tobacco smoke may also be responsible for the development of chronic cough in both children and adults. The present study analyses the effects of tobacco smoke exposure as potential causes of chronic cough. A panel of PubMed-based searches was performed relating the symptom of cough to various forms of tobacco smoke exposure. It was found that especially prenatal and postnatal exposures to ETS have an important influence on children's respiratory health including the symptom of cough. These effects may be prevented if children and pregnant women are protected from exposure to ETS. Whereas the total number of studies adressing the relationship between cough and ETS exposure is relatively small, the present study demonstrated that there is a critical amout of data pointing to a causative role of environmental ETS exposure for the respiratory symptom of cough. Since research efforts have only targeted this effect to a minor extent, future epidemiological and experimental studies are needed to further unravel the relation between ETS and cough.

Chronic exposure to second hand smoke and 30-day prognosis of patients hospitalised with acute coronary syndromes: the Greek study of acute coronary syndromes

OBJECTIVE

To investigate the association between chronic exposure to second hand smoke (SHS) and the short-term prognosis of patients hospitalised with acute coronary syndromes.

METHODS

Between 1 October 2003 and 30 September 2004, 2172 consecutive patients enrolled with acute coronary syndromes at the cardiology clinics or the emergency units of six major hospitals, in Greece were studied. Exposure to SHS was measured through a questionnaire administered during a specific interview, after the second day of hospitalisation. The main outcome of interest was the 30-day status of these patients (death, or rehospitalisation due to coronary heart disease).

RESULTS

1003 (46%) of the patients were exposed to SHS. Patients reporting exposure to SHS had 61% (95% CI 14% to 118%) higher risk of having an event during the first 30 days after hospitalisation as compared with patients who were not exposed to SHS, after taking into account the effect of several potential confounders. A dose-response linear relationship was observed between the risk of having recurrent events and the years of exposure to SHS (rho = 0.17, p<0.001).

CONCLUSIONS

Exposure to SHS increases considerably the risk of recurrent events in patients who had survived a cardiac event.

Cardiovascular effects of secondhand smoke: nearly as large as smoking

BACKGROUND

Secondhand smoke increases the risk of coronary heart disease by approximately 30%. This effect is larger than one would expect on the basis of the risks associated with active smoking and the relative doses of tobacco smoke delivered to smokers and nonsmokers.

METHODS AND RESULTS

We conducted a literature review of the research describing the mechanistic effects of secondhand smoke on the cardiovascular system, emphasizing research published since 1995, and compared the effects of secondhand smoke with the effects of active smoking. Evidence is rapidly accumulating that the cardiovascular system--platelet and endothelial function, arterial stiffness, atherosclerosis, oxidative stress, inflammation, heart rate variability, energy metabolism, and increased infarct size--is exquisitely sensitive to the toxins in secondhand smoke. The effects of even brief (minutes to hours) passive smoking are often nearly as large (averaging 80% to 90%) as chronic active smoking.

CONCLUSIONS

The effects of secondhand smoke are substantial and rapid, explaining the relatively large risks that have been reported in epidemiological studies.

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

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

Second-hand smoke-induced cardiac fibrosis is related to the Fas death receptor apoptotic pathway without mitochondria-dependent pathway involvement in rats

Exposure to environmental tobacco smoke has been epidemiologically linked to heart disease among nonsmokers. However, the molecular mechanism behind the pathogenesis of cardiac disease is unknown. In this study, we found that Wistar rats, exposed to tobacco cigarette smoke at doses of 5, 10, or 15 cigarettes for 30 min twice a day for 1 month, had a dose-dependently reduced heart weight to body weight ratio and enhanced interstitial fibrosis as identified by histopathologic analysis. The mRNA and activity of matrix metalloprotease-2 (MMP-2), representing the progress of cardiac remodeling, were also elevated in the heart. In addition, we used reverse-transcriptase polymerase chain reaction and Western blotting to demonstrate significantly increased levels of the apoptotic effecter caspase-3 in treated animal hearts. Dose-dependently elevated mRNA and protein levels of Fas, and promoted apoptotic initiator caspase-8 (active form), a molecule of a death-receptor-dependent pathway, coupled with unaltered or decreased levels of cytosolic cytochrome c and the apoptotic initiator caspase-9 (active form), molecules of mitochondria-dependent pathways, may be indicative of cardiac apoptosis, which is Fas death-receptor apoptotic-signaling dependent, but not mitochondria pathway dependent in rats exposed to second-hand smoke (SHS). With regard to the regulation of survival pathway, using dot blotting, we found cardiac insulin-like growth factor-1 (IGF-1) and IGF-1 receptor mRNA levels to be significantly increased, indicating that compensative effects of IGF-1 survival signaling could occur. In conclusion, we found that the effects of SHS on cardiomyocyte are mediated by the Fas death-receptor-dependent apoptotic pathway and might be related to the epidemiologic incidence of cardiac disease of SHS-exposed nonsmokers.

Environmental tobacco smoke and ischemic heart disease

Cohort and case control studies show a 30% excess risk of ischemic heart disease in nonsmokers whose spouses smoke compared with that in nonsmokers whose spouses do not smoke. There is a nonlinear dose-response; the excess risk from actively smoking 20 cigarettes/day is only 80%. Large cohort studies of active smoking support the nonliner dose-response (the excess risk in smokers of 5 cigarettes/day is about 50%). Animal studies show a pronounced vascular effect of environmental tobacco smoke. In experimental studies passive and active smoking have similar effects on platelet aggregation. The collective evidence supports a significant effect of low dose tobacco smoke exposure in causing ischaemic heart disease.

Association between exposure to environmental tobacco smoke and the development of acute coronary syndromes: the CARDIO2000 case-control study

OBJECTIVE

To investigate the association between environmental tobacco smoke (ETS) exposure (at least 30 minutes a day) and the risk of developing acute coronary syndromes (ACS).

DESIGN AND SETTING

The CARDIO2000 is a case-control study which was conducted in Greece from 2000 to 2001. Cases included 847 individuals with a first event of ACS and 1078 cardiovascular disease-free controls. Cases and controls were frequency matched on age (within three years of age), sex, and region.

MAIN OUTCOME MEASURES

ACS was defined as a diagnosis of first acute myocardial infarction or unstable angina. Main independent variable: Exposure to ETS was measured by self report as follows: after the second day of hospitalisation for the cases, and at the entry for the controls, participants were asked whether they were currently exposed to tobacco smoke from other people (home and/or work) for more than 30 minutes a day. The responses were categorised into three levels: no exposure, occasional exposure (< 3 times per week), and regular exposure. In addition participants were asked how many years they had been exposed. Because these were self reported assessments and prone to bias, the results were compared to reports obtained from subjects' relatives or friends, using the Kendal's tau coefficient that showed high agreement.

RESULTS

731 (86%) of the patients and 605 (56%) of the controls reported current exposure of 30 minutes per day or more to ETS. Among current non-smokers, cases were 47% more likely to report regular exposure to ETS (odds ratio (OR) 1.47, 95% confidence interval (CI) 1.26 to 1.80) compared to controls. Exposure to ETS at work was associated with a greater risk of ACS compared to home exposure (+97% v +33%). The risk of ACS was also raised in active smokers (OR 2.83, 95% CI 2.07 to 3.31) regularly exposed to ETS.

CONCLUSIONS

This study supports the hypothesis that exposure to ETS increases the risk of developing ACS. The consistency of these findings with the existing totality of evidence presented in the literature supports the role of ETS in the aetiology of ACS.

The association between secondhand smoke and the risk of developing acute coronary syndromes, among non-smokers, under the presence of several cardiovascular risk factors: The CARDIO2000 case-control study

BACKGROUND

The purpose of this study was to investigate the association between secondhand smoke and the risk of developing a first event of acute coronary syndromes (ACS), i.e. acute myocardial infarction or unstable angina, among non-smokers, in relation to the presence of several other cardiovascular risk factors.

METHODS

Eight hundred and forty-eight patients with first event of ACS and 1078 cardiovascular disease-free matched controls completed a detailed questionnaire regarding their exposure to secondhand smoke, among other investigated parameters.

RESULTS

Two hundred and ninety-seven (35%) of the patients and 259 (24%) of the controls were defined as secondhand smokers. After controlling for several potential confounders, the results showed that non-smokers occasionally (< 3 time per week) exposed to cigarette smoke were associated with 26% higher risk of ACS (OR = 1.26, P-value < 0.01) compared to non-smokers not exposed to smoke, while regular exposure is associated with 99% higher risk of developing ACS (OR = 1.99, P-value < 0.001). Moreover, the previous risk increases progressively from 15% to 256% if one or more of the classical cardiovascular risk factors (i.e. hypertension, hypercholesterolemia, diabetes mellitus, sedentary life and family history of premature coronary heart disease) are present.

CONCLUSIONS

Consequently, this study supports the hypothesis that even occasional secondhand smoke increases the risk of developing acute coronary syndromes, especially when other risk factors are present. Given the high prevalence of cigarette smoking, the public health consequences of passive smoking with regard to coronary heart disease are important.

The epidemiology of hypertension in South America

Although cardiovascular disease (CVD) is the leading cause of death and disability in the majority of the countries in Latin America we have few data about regional differences on this topic. Developing countries have scarce epidemiological data on cardiovascular (CV) risk factor prevalence and subsequently in their control and treatment. The load of the CV risk factors, especially hypertension, remains uncertain. The methodology of investigation varies from country to country and the criteria to define 'hypertension' is different according to the survey year. Data on CVD from USA and Europe have been extrapolated to our continent but recently two large epidemiological studies have been conducted in the southern region: FRICAS, primary prevention, and PRESEA, secondary prevention. The first pointed out the importance of each cardiovascular risk factor, including hypertension, in the development of acute myocardial infarction (AMI), and the second showed the poor control of them and the necessity to improve them.

Exposure to environmental tobacco smoke: association with personal characteristics and self reported health conditions

STUDY OBJECTIVE

To examine the association between exposure to environmental tobacco smoke (ETS) and demographic, lifestyle, occupational characteristics and self reported health conditions.

DESIGN

Cross sectional study, using data from multiphasic health checkups between 1979 and 1985.

SETTING

Large health plan in Northern California, USA.

PARTICIPANTS

16 524 men aged 15-89 years and 26 197 women aged 15-105 years who never smoked.

RESULTS

Sixty eight per cent of men and 64 per cent of women reported any current ETS exposure (at home, in small spaces other than home or in large indoor areas). The exposure time from all three sources of ETS exposure correlated negatively with age. Men and women reporting high level ETS exposure were more likely to be black and never married or separated/divorced, to have no college or partial college education, to consume three alcoholic drink/day or more and to report exposure to several occupational hazards. Consistent independent relations across sexes were found between any current exposure to ETS and a positive history of hay fever/asthma (odds ratio (OR)=1.22 in men, 1.14 in women), hearing loss (OR=1.30 in men, 1.27 in women), severe headache (OR=1.22 in men, 1.17 in women), and cold/flu symptoms (OR=1.52 in men, 1.57 in women). Any current ETS exposure was also associated with chronic cough (OR=1.22) in men and with heart disease (OR=1.10) in women. Self reported stroke was inversely associated with any current ETS exposure in men (OR=0.27). No associations were noted for cancer or tumour and for migraine.

CONCLUSION

ETS exposure correlated with several personal characteristics potentially associated with adverse health outcomes. Although the study design precluded causal inference, ETS exposure was associated with several self reported acute and chronic medical conditions.

Environmental tobacco smoke and myocardial infarction among never-smokers in the Stockholm Heart Epidemiology Program (SHEEP)

An increased risk for myocardial infarction (MI) related to environmental tobacco smoke (ETS) exposure has previously been reported, but several aspects of the association are still uncertain. We studied the MI risk associated with ETS exposure among 334 nonfatal never-smoking MI cases and 677 population controls, 45-70 years of age, in Stockholm County. A postal questionnaire with a telephone follow-up provided information on ETS exposure and other potential risk factors for MI. After adjustment for age, gender, hospital catchment area, body mass index, socioeconomic status, job strain, hypertension, diet, and diabetes mellitus, the odds ratio for MI was 1.58 (95% confidence interval = 0.97-2.56) for an average daily exposure of 20 cigarettes or more from the spouse. Combined exposure from spouse and work showed an increasing odds ratio for MI, up to 1.55 (95% confidence interval = 1.02-2.34) in the highest category of weighted duration, that is, more than 90 "hour-years" of exposure (1 "hour-year" = 365 hours, or 1 hour per day for 1 year). In addition, more recent exposure appeared to convey a higher risk. Our data confirm an increased risk of MI from exposure to ETS and suggest that intensity of spousal exposure, combined exposure from spouse and work, and time since last exposure are important.

The miseries of passive smoking

Passive smoking is defined as an involuntary exposure to a combined but diluted cigarette sidestream smoke (SS, gas and particle phases that are evolved from the smoldering end of a cigarette while the smoker is not puffing) and the exhaled smoke from smokers. SS contains numerous cytotoxic substances such as polycyclic aromatic hydrocarbons (PAHs), aromatic amines, nitrosamines, heavy metals, poisonous gases, pesticide residues, and radioactive elements in quantities much higher than those found from the cigarette mainstream smoke (MS) which is puffed by smokers. Passive smoking is found to be the cause of death from cancers and cardiac disease. Furthermore, it damagingly involves reproductive organs, the nervous system, genetic materials, and is particularly hazardous to mother and child during pregnancy and to those with a history of asthma, chronic infections, induced or earned immune deficiency, or predisposed susceptibility.

Passive smoking and the risk of coronary heart disease--a meta-analysis of epidemiologic studies

BACKGROUND

The effect of passive smoking on the risk of coronary heart disease is controversial. We conducted a meta-analysis of the risk of coronary heart disease associated with passive smoking among nonsmokers.

METHODS

We searched the Medline and Dissertation Abstracts Online data bases and reviewed citations in relevant articles to identify 18 epidemiologic (10 cohort and 8 case-control) studies that met prestated inclusion criteria. Information on the designs of the studies, the characteristics of the study subjects, exposure and outcome measures, control for potential confounding factors, and risk estimates was abstracted independently by three investigators using a standardized protocol.

RESULTS

Overall, nonsmokers exposed to environmental smoke had a relative risk of coronary heart disease of 1.25 (95 percent confidence interval, 1.17 to 1.32) as compared with nonsmokers not exposed to smoke. Passive smoking was consistently associated with an increased relative risk of coronary heart disease in cohort studies (relative risk, 1.21; 95 percent confidence interval, 1.14 to 1.30), in case-control studies (relative risk, 1.51; 95 percent confidence interval, 1.26 to 1.81), in men (relative risk, 1.22; 95 percent confidence interval, 1.10 to 1.35), in women (relative risk, 1.24; 95 percent confidence interval, 1.15 to 1.34), and in those exposed to smoking at home (relative risk, 1.17; 95 percent confidence interval, 1.11 to 1.24) or in the workplace (relative risk, 1.11; 95 percent confidence interval, 1.00 to 1.23). A significant dose-response relation was identified, with respective relative risks of 1.23 and 1.31 for nonsmokers who were exposed to the smoke of 1 to 19 cigarettes per day and those who were exposed to the smoke of 20 or more cigarettes per day, as compared with nonsmokers not exposed to smoke (P=0.006 for linear trend).

CONCLUSIONS

Passive smoking is associated with a small increase in the risk of coronary heart disease. Given the high prevalence of cigarette smoking, the public health consequences of passive smoking with regard to coronary heart disease may be important.