Coronary events and exposure to environmental tobacco smoke: a case-control study from Australia and New Zealand

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.

Female vulnerability to the effects of smoking on health outcomes in older people

Cigarette smoking is among the leading risk factors for mortality and morbidity. While men have a higher smoking prevalence, mechanistic experiments suggest that women are at higher risk for health problems due to smoking. Moreover, the comparison of smoking effects on multiple conditions and mortality for men and women has not yet been done in a population-based group with race/ethnic diversity. We used proportional hazards models and restricted mean survival time to assess differences in smoking effects by sex for multiple health outcomes using data from the U.S. Health and Retirement Study (HRS), a population-representative cohort of individuals aged 50+ (n = 22,708, 1992-2014). Men had experienced more smoking pack-years than women (22.0 vs 15.6 average pack-years). Age of death, onset of lung disorders, heart disease, stroke, and cancer showed dose-dependent effects of smoking for both sexes. Among heavy smokers (>28 pack-years) women had higher risk of earlier age of death (HR = 1.3, 95%CI:1.03-1.65) and stroke (HR = 1.37, 95%CI:1.02-1.83). Risk of cancer and heart disease did not differ by sex for smokers. Women had earlier age of onset for lung disorders (HR = 2.83, 95%CI:1.74-4.6), but men risk due to smoking were higher (Smoking-Sex interaction P<0.02) than women. Passive smoke exposure increased risk of earlier heart disease (HR = 1.33, 95%CI:1.07-1.65) and stroke (HR:1.54, 95%CI:1.07-2.22) for non-smokers, mainly in men. Smoking cessation after 15 years partially attenuated the deleterious smoking effects for all health outcomes. In sum, our results suggest that women are more vulnerable to ever smoking for earlier death and risk of stroke, but less vulnerable for lung disorders. From an epidemiological perspective, sex differences in smoking effects are important considerations that could underlie sex differences in health outcomes. These findings also encourage future mechanistic experiments to resolve potential mechanisms of sex-specific cigarette smoke toxicity.

Cardiovascular risk factors of hypertension, smoking and obesity: Emerging concerns among Pathan and Persian young adults?

Background: Hypertension was considered as a disease of the elderly but due to unhealthy dietary and lifestyle changes its incidence has increased in younger population. Smoking and obesity are emerging concerns the world is facing globally in younger age groups. This study is therefore aimed to identify these cardiovascular risk factors among Pathan and Persian young adults.

Methods: It was a cross-sectional study carried out at multiple undergraduate, postgraduate educational institutes and hospitals using non-probability convenient sampling among young adults aged between 15 to 40 years for a period of six months from Apr 1st, 2017 to Sep 30th, 2017. Mean±SD was calculated for continuous variables and categorical variables were expressed as frequencies. Chi-square test and Fisher exact test were used for statistical analysis.

Results: A total of 708 subjects were included. Mean±SD age was 26.12±3.7 years. Out of 708, 300(42.37%) were smokers with 209 (29.52%) active and 91 (12.85%) passive smokers. Among smokers, 216 (30.5%) were males while 84 (11.87%) were females. A total of 432 (61.02%) subjects were not doing any exercise, and 636 (89.83%) were consuming junk food. A total of 165 (23.3%) subjects were overweight, and 15 (2.1%) were obese. Stage-1 hypertension was present in 72 (10.2%), while 16 (2.25%) subjects had stage-2 hypertension.

Conclusion: There is an increased prevalence of cardiovascular risk factors which includes hypertension, smoking, and obesity among Pathan and Persian young adults.

Environmental tobacco smoke exposure and heart disease: A systematic review

AIM

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

METHODS

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

RESULTS

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

CONCLUSION

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

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.

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 tobacco smoke and cardiovascular disease risk: an epidemiological review

In this review, we have sought to examine the epidemiological, basic science, and public health data regarding the association between second-hand smoke (SHS) exposure and the development of coronary heart disease (CHD). SHS increases the risk of CHD by 25-30% according to multiple cohort, case-control, and meta-analytical studies. Physiologic and basic science research suggest that the mechanisms by which SHS affects the cardiovascular system are multiple and include increased thrombogenesis and low-density lipoprotein oxidation, decreased exercise tolerance, dysfunctional flow-mediated vasodilatation, and activation of inflammatory pathways with concomitant oxidative damage and impaired vascular repair. As a result, chronic exposure promotes atherogenesis and the development of cardiovascular disease, increasing the risk of having an acute coronary syndrome (ACS). With the implementation of statewide and nationwide public smoke-free legislation across the United States and Europe, respectively, over the last 10-15 years, there has been a significant and reciprocal decline in the incidence of emergency admissions for ACS by an average 17% despite persistent attempts on the part of the tobacco industry to diminish the correlation between SHS exposure and CHD. These findings underscore the importance of the effects of smoking legislation on community health.

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

Objectives

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

Methods

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

Results

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

Conclusion

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

The impact of a 100% smoke-free law on the health of hospitality workers from the city of Neuquén, Argentina

Objectives

The objective of this study was to evaluate the impact of 100% smoke-free environment legislation on respiratory and sensory irritation symptoms and respiratory function among bar and restaurant workers from the city of Neuquén, Argentina.

Methods

Pre-ban and post-ban studies without a comparison group in an Argentinean city were conducted. A baseline survey and spirometric measurements were performed with a total of 80 bar and restaurant workers 1 month before (October 2007) and 3 months after (March 2008) the implementation of the new 100% smoke-free legislation.

Results

A significant reduction in secondhand smoke exposure was observed after the enactment and enforcement of the new legislation, and an important reduction in respiratory symptoms (from a pre-ban level of 57.5% to a post-ban level of only 28.8%). The reduction of sensory irritation symptoms was even higher. From 86.3% of workers who reported at least one sensory irritation symptom in October 2007, only 37.5% reported the same symptoms in March 2008. Also, data obtained by spirometry showed a significant forced vital capacity increase.

Conclusions

Consistent with other studies, 100% smoke-free legislation improved short-term health outcomes in the sample and should be implemented nationwide. Furthermore, undertaking this study has been highly important in promoting 100% smoke-free environment legislation at the workplace as a legitimate right of hospitality workers, and in reducing social acceptance of designated smoking areas in bars and restaurants.

Prevalence and Predictors of Environmental Tobacco Smoke Exposure among Adolescents in Cambodia

OBJECTIVE

To estimate the prevalence and predictors of environmental tobacco smoke (ETS) exposure among nonsmoking adolescents in Cambodia.

MATERIALS AND METHODS

Analysis of data from the Global Youth Tobacco Survey (GYTS) conducted in 2003 in Cambodia. Data were analysed to obtain the prevalence of ETS exposure at home and elsewhere by age and gender. Logistic regression analysis was conducted to assess the association between ETS and gender, age, smoking status of parents and friends.

RESULTS

67.1% (64.0, 70.0) males and 67.4% (64.2, 70.5) females reported being exposed to ETS either at home or elsewhere. Adolescents who had one or both smoking parents had a more than three times the odds of ETS exposure at home (OR = 3.71; 95% CI (3.02, 4.57)). Those who had smoking friends were more likely to be exposed to ETS both at home and outside home (OR = 1.74; 95% CI (1.36, 2.24)). The overall proportion of adolescents exposed to ETS outside home was higher than those exposed at home (P < 0.001), suggesting that exposure in public areas was the main form of ETS among adolescents in Cambodia.

CONCLUSIONS

Exposure to ETS is high among adolescent in Cambodia, which indicates an urgent need for specific measures, policies and regulations to protect nonsmoker Cambodian adolescents both within and outside home.

Are there health benefits associated with comprehensive smoke-free laws

INTRODUCTION

In the past few years, comprehensive smoke-free laws that prohibit smoking in all workplaces have been introduced in many jurisdictions in the US, Canada, and Europe. In this paper, we review published studies to ascertain if there is any evidence of health benefits resulting from the implementation of these laws.

METHODS

All papers relating to smoke-free legislation published in or after 2004 were considered for inclusion in this review. We used Pubmed, Google scholar, and Web of Science as the main search tools. The primary focus of the paper is on health outcomes, and thus many papers that only report exposure data are not included.

RESULTS

Studies using subjective measures of respiratory health based on questionnaire data alone consistently reported that workers experience fewer respiratory and irritant symptoms following the introduction of smoke-free laws. Some studies also found measured improvements in the lung function of workers. However, the most dramatic health outcome associated with smoke-free laws has been the reduction in myocardial infarction in the general population. This outcome has been observed in the US, Canada, and Europe, with studies reporting reductions of between 6 and 40%, post-legislation, the larger reductions being mostly from studies with smaller population groups. The evidence as to whether these smoke-free laws have helped smokers to stop smoking or to reduce tobacco consumption is less clear.

CONCLUSIONS

There is now significant body of published literature that demonstrates that smoke-free laws can lead to improvements in the health of both workers who are occupationally exposed and of the general population. There is no longer any reason why non-smokers should be exposed to SHS in any workplace. We recommend that all countries adopt national smoke-free laws that are in line with article 8 of the WHO Framework Convention on Tobacco Control that sets out recommendations for the development, implementation, and enforcement of national, comprehensive smoke-free laws.

Secondhand smoke exposure, pulmonary function, and cardiovascular mortality

PURPOSE

Cardiovascular disease and obstructive lung disease are leading global causes of death. Despite this, the impact of secondhand smoke (SHS) exposure on pulmonary function and cardiovascular disease remains uncertain. Our goal was to elucidate the association between baseline SHS exposure and the risk of lung function decline and cardiovascular mortality over a period of nearly a decade.

METHODS

We used data from a longitudinal cohort study of 1,057 older adults to study the association between baseline SHS exposure and the risk of lung function decline and cardiovascular mortality. The effect of SHS exposure on cardiovascular mortality may be mediated by its influence on FEV1 and biological processes captured by measurement of FEV1. Alternatively, the effect of SHS may be mediated by baseline cardiovascular disease status, which reflects the combined effects of traditional cardiovascular risk factors. To correctly estimate the effect of SHS and FEV1 on cardiovascular mortality, we used marginal structural models (MSMs) that took into account the mediating effects of FEV1 and baseline cardiovascular disease in the causal pathway.

RESULTS

In longitudinal multivariate analyses, lifetime cumulative home and work SHS exposure were associated with a greater decline of FEV1 (-15 mL/s; 95% CI, -29 to -1.3 mL/s and -41 mL/s; 95% CI, -55 to -28 mL/s per 10-year cumulative exposure, respectively). Lifetime home SHS exposure was associated with a greater risk of cardiovascular mortality in both conventional multivariate analysis (HR, 1.10 per 10 years of exposure; 95% CI, 0.99 to 1.24) and the MSM for FEV1 (HR, 1.06; 95% CI, 0.95 to 1.19) and baseline cardiovascular disease (HR for subjects with no baseline cardiovascular disease, 1.39; 95% CI, 1.17 to 1.66).

CONCLUSIONS

Lifetime SHS exposure appears to result in a greater decline in lung function and risk of cardiovascular mortality, taking into account confounders and the mediating effect of FEV1 and baseline cardiovascular disease.

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.

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.

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.