Secondhand smoke exposure induces acutely airway acidification and oxidative stress

Towards Reference Values for Malondialdehyde on Exhaled Breath Condensate: A Systematic Literature Review and Meta-Analysis

Many pathological conditions and certain airway exposures are associated with oxidative stress (OS). Malondialdehyde (MDA) is an end-product of the oxidation of lipids in our cells and is present in all biological matrices including exhaled breath condensate (EBC). To use MDA as a biomarker of OS in EBC, a reference interval should be defined. Thus, we sought to summarize reference values reported in healthy adult populations by performing a systematic review and meta-analysis using a standardized protocol registered in PROSPERO (CRD42020146623). Articles were retrieved from four major databases and 25 studies with 28 subgroups were included. Defining the distribution of MDA measured in reference populations with a detection combined with a separation technique still represents a challenge due to the low number of studies available, different analytical methods used, and questionable methodological qualities of many studies. The most salient methodological drawbacks have been in data collection and reporting of methods and study results by the researchers. The lack of compliance with the recommendations of the European Respiratory Society and American Thoracic Society was the major limitation in the current research involving EBC. Consequently, we were unable to establish a reference interval for MDA in EBC.

Exposure to lead-free frangible firing emissions containing copper and ultrafine particulates leads to increased oxidative stress in firing range instructors

Background

Since the introduction of copper based, lead-free frangible (LFF) ammunition to Air Force small arms firing ranges, instructors have reported symptoms including chest tightness, respiratory irritation, and metallic taste. These symptoms have been reported despite measurements determining that instructor exposure does not exceed established occupational exposure limits (OELs). The disconnect between reported symptoms and exposure limits may be due to a limited understanding of LFF firing byproducts and subsequent health effects. A comprehensive characterization of exposure to instructors was completed, including ventilation system evaluation, personal monitoring, symptom tracking, and biomarker analysis, at both a partially enclosed and fully enclosed range.

Results

Instructors reported symptoms more frequently after M4 rifle classes compared to classes firing only the M9 pistol. Ventilation measurements demonstrated that airflow velocities at the firing line were highly variable and often outside established standards at both ranges. Personal breathing zone air monitoring showed exposure to carbon monoxide, ultrafine particulate, and metals. In general, exposure to instructors was higher at the partially enclosed range compared to the fully enclosed range. Copper measured in the breathing zone of instructors, on rare occasions, approached OELs for copper fume (0.1 mg/m³). Peak carbon monoxide concentrations were 4–5 times higher at the partially enclosed range compared to the enclosed range and occasionally exceeded the ceiling limit (125 ppm). Biological monitoring showed that lung function was maintained in instructors despite respiratory symptoms. However, urinary oxidative stress biomarkers and urinary copper measurements were increased in instructors compared to control groups.

Conclusions

Consistent with prior work, this study demonstrates that symptoms still occurred despite exposures below OELs. Routine monitoring of symptoms, urinary metals, and oxidative stress biomarkers can help identify instructors who are particularly affected by exposures. These results can assist in guiding protective measures to reduce exposure and protect instructor health. Further, a longitudinal study is needed to determine the long-term health consequences of LFF firing emissions exposure.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12989-022-00471-0.

Passive Smoking and Risk of Gestational Diabetes Mellitus among Nonsmoking Women: A Prospective Cohort Study in China

Background: Increasing evidence has shown that active smoking can increase the risk of gestational diabetes mellitus (GDM), but the effect of passive smoking is still unknown. Women in pregnancy are vulnerable to secondhand smoke. This study explored the association of passive smoking with GDM in China. Method: A total of 3083 nonsmoking pregnant women living in Beijing were recruited into a prospective cohort study. Sociodemographic and passive smoking data were collected with structured questionnaires during face-to-face interviews. Glucose levels were measured by physicians according to standard protocols. Multivariate logistic regression was performed for the association estimation after accounting for potential confounders. Result: In total, 562 of the 3083 participants developed GDM (18.23%); 779 participants (25.27%) reported exposure to passive smoking. After adjusting for age, BMI, ethnicity, education, occupation, and parity, passive smoking conferred an approximately 1.4-fold risk increase in GDM (adjusted odds ratio (OR) = 1.37, 95% confidence interval (CI): (1.11, 1.70)). The adjusted ORs with 95% CIs for passive smoking levels of <1, 1−6, and ≥7 times per week were 1.21 (0.94, 1.55), 1.81 (1.22, 2.69), and 1.70 (1.02, 2.84), respectively. An obvious passive-smoking−GDM association was observed among only nulliparous women (adjusted OR = 1.45, 95% CI: (1.14, 1.85)). Conclusion: Frequent exposure to secondhand smoke could increase the risk of GDM among nonsmoking pregnant women. Parity status might modify their association. Public policies should be advocated to prevent passive smoking among this population.

Biomarkers for the adverse effects on respiratory system health associated with atmospheric particulate matter exposure

Large amounts of epidemiological evidence have confirmed the atmospheric particulate matter (PM_2.5) exposure was positively correlated with the morbidity and mortality of respiratory diseases. Nevertheless, its pathogenesis remains incompletely understood, probably resulting from the activation of oxidative stress, inflammation, altered genetic and epigenetic modifications in the lung upon PM_2.5 exposure. Currently, biomarker investigations have been widely used in epidemiological and toxicological studies, which may help in understanding the biologic mechanisms underlying PM_2.5-elicited adverse health outcomes. Here, the emerging biomarkers to indicate PM_2.5-respiratory system interactions were summarized, primarily related to oxidative stress (ROS, MDA, GSH, etc.), inflammation (Interleukins, FE_NO, CC16, etc.), DNA damage (8-OHdG, γH2AX, OGG1) and also epigenetic modulation (DNA methylation, histone modification, microRNAs). The identified biomarkers shed light on PM_2.5-elicited inflammation, fibrogenesis and carcinogenesis, thus may favor more precise interventions in public health. It is worth noting that some inconsistent findings may possibly relate to the inter-study differentials in the airborne PM_2.5 sample, exposure mode and targeted subjects, as well as methodological issues. Further research, particularly by -omics technique to identify novel, specific biomarkers, is warranted to illuminate the causal relationship between PM_2.5 pollution and deleterious lung outcomes.

Second-Hand Smoke Exposure Associated with Risk of Respiratory Symptoms, Asthma, and COPD in 20,421 Adults from the General Population

Rationale

Individuals exposed to second-hand smoking may be more susceptible to asthma and chronic obstructive pulmonary disease (COPD). We investigated the risk of respiratory symptoms, asthma, and COPD in adults exposed to second-hand smoking at different stages of life in the general population.

Methods

We identified individuals who had been exposed to second-hand smoking in childhood only, adulthood only, or lifelong in a cohort of 20,421 adults from the Danish General Suburban Population Study and recorded respiratory symptoms, lung function, asthma, and COPD as outcomes.

Results

Among 20,421 adults from the general population, 2,551 (12%) had been lifelong exposed to second-hand smoking, 459 (2%) had been exposed in adulthood only, and 13,998 (69%) had been exposed in childhood only; the mean ages of the three groups were 54 years, 55 years, and 57 years, respectably, compared with 56 years in non-exposed individuals (P<0.001). Equivalent values for the prevalence of current smoking were 25%, 20%, and 18% versus 12% (P<0.001). After adjustment for age, smoking, and sex, the odds ratios for wheezing, severe dyspnoea, cough on exertion, and asthma increased as a function of second-hand smoke exposure (Ps≤0.004); individuals who had been exposed to second-hand smoking lifelong, in adulthood only, or in childhood only versus non-exposed had increased odds ratios for wheezing of 1.62 (95% CI=1.41–1.87), 1.50 (1.15–1.94), and 1.16 (1.04–1.30). Corresponding values were 2.08 (1.52–2.85), 2.05 (1.22-3-44), and 1.23 (0.95–1.59) for severe dyspnoea, 1.56 (1.33–1.83), 1.53 (1.15–2.02), and 1.19 (1.05–1.35) for cough on exertion, 1.36 (1.14–1.63), 1.49 (1.09–2.05), and 1.13 (0.99–1.30) for asthma, and 1.24 (1.03–1.48), 1.25 (0.90–1.74), and 1.09 (0.96–1.24) for COPD. The population attributable fractions of asthma and COPD due to lifelong second-hand smoke exposure were 4.3% and 2.9%.

Conclusion

Individuals exposed to lifelong second-hand smoking have increased risks of respiratory symptoms, asthma, and COPD, and may account for 4.3% and 2.9% of people with asthma and COPD in the general population.

Lung function changes in patients with chronic obstructive pulmonary disease (COPD) and asthma exposed to secondhand smoke in outdoor areas

BACKGROUND

Further evidence is needed on the effects that short- and long-term exposure to secondhand smoke (SHS) have on the respiratory health of patients with lung disease. Within the TackSHS project we aimed to assess the acute respiratory effects in lung function that result from short-term SHS exposure among patients with asthma and chronic obstructive pulmonary disease (COPD).

METHODS

The study design was an intervention trial with measurements before/after exposure to SHS in legal outdoor smoking areas. We studied patients with asthma or COPD from Czechia, Ireland, and Spain. Forced spirometry, peak flow and carbon monoxide (CO) measurements were performed pre- and 24 h post- exposure.

RESULTS

Overall, 60 patients were studied, 30 with asthma, and 30 with COPD; 35 (58.3%) were female. There were no significant differences observed in exhaled CO between pre- and 24 h post-exposure neither in women (p = 0.210), nor in men (p = 0.169).A statistically significant decrease in forced vital capacity (FVC) was seen, overall, in asthma participants (p = 0.02) and in forced expiratory volume in the first second (FEV₁), (p = 0.02), FVC (p = 0.04) and peak expiratory flow rate (PEFR) (p = 0.04) in female asthmatic participants. The observed decreases in respiratory measurements in COPD were not significant. There were no reported increases in symptoms, respiratory medication, or use of health services 24 h after the exposure.

CONCLUSION

We conclude that acute, short-term SHS exposure had a statistically significant effect on spirometry in female asthma patients but did not significantly modify spirometric indices 24 h later in COPD patients.

Adrenal βarrestin1 targeting for tobacco-associated cardiac dysfunction treatment: Aldosterone production as the mechanistic link

Tobacco kills 6 million people annually and its global health costs are continuously rising. The main addictive component of every tobacco product is nicotine. Among the mechanisms by which nicotine, and its major metabolite, cotinine, contribute to heart disease is the renin-angiotensin-aldosterone system (RAAS) activation. This increases aldosterone production from the adrenals and circulating aldosterone levels. Aldosterone is a mineralocorticoid hormone with various direct harmful effects on the myocardium, including increased reactive oxygen species (ROS) generation, which contributes significantly to cardiac mitochondrial dysfunction and cardiac aging. Aldosterone is produced in the adrenocortical zona glomerulosa (AZG) cells in response to angiotensin II (AngII), activating its type 1 receptor (AT1R). The AT1R is a G protein-coupled receptor (GPCR) that leads to aldosterone biosynthesis and secretion, via signaling from both Gq/11 proteins and the GPCR adapter protein βarrestin1, in AZG cells. Adrenal βarrestin1 is essential for AngII-dependent adrenal aldosterone production, which aggravates heart disease. Since adrenal βarrestin1 is essential for raising circulating aldosterone in the body and tobacco compounds are also known to elevate aldosterone levels in smokers, accelerating heart disease progression, our central hypothesis is that nicotine and cotinine increase aldosterone levels to induce cardiac injury by stimulating adrenal βarrestin1. In the present review, we provide an overview of the current literature of the physiology and pharmacology of adrenal aldosterone production regulation, of the effects of tobacco on this process and, finally, of the effects of tobacco and aldosterone on cardiac structure and function, with a particular focus on cardiac mitochondrial function. We conclude our literature account with a brief experimental outline, as well as with some therapeutic perspectives of our pharmacological hypothesis, that is that adrenal βarrestin1 is a novel molecular target for preventing tobacco-induced hyperaldosteronism, thereby also ameliorating tobacco-related heart disease development.

The Asti Study: The Induction of Oxidative Stress in A Population of Children According to Their Body Composition and Passive Tobacco Smoking Exposure

Obesity and exposure to second-hand tobacco smoking (SHS) may influence oxidative stress (OS) levels, especially in children. This study investigated body composition and SHS influence on OS induction in the paediatric population. The first purpose was identifying an appropriate BMI standard for adiposity assessment in OS investigations. Secondly, SHS and obesity were analysed as inductors of OS. The epidemiologic sample involved 330 children. Three BMI (body mass index) references (IOTF, CDC, and WHO) and an impedentiometric scale supplied body-composition measurements. Partecipants filled out a questionnaire and provided urinary samples for biomarker quantifications: isoprostane (15-F2t IsoP) and cotinine as OS and SHS biomarker, respectively. Obesity prevalence changed over different BMI references (14%, 21%, and 34% for IOTF, CDC, and WHO, respectively). Obese children, by IOTF, showed an increase of 56% in 15-F2t IsoP compared to those normal weight (p = 0.020). Children belonging to the third and the fourth cotinine quartile compared to those of the first quartile had higher 15-F2t IsoP (1.45 ng/mg, 95% CI: 1.06⁻1.97, p = 0.020 and 2.04 ng/mg, 95% CI: 1.55⁻2.69, p < 0.0001, respectively). Obesity assessment in children requires appropriate BMI reference depending on research field. Both SHS exposure and obesity may increase OS in children.

Associations Between Secondhand Tobacco Smoke Exposure and Nicotine Dependence and Smoking Cessation Attempts Among Adult Tobacco Users With a Psychiatric Disorder

INTRODUCTION

Secondhand smoke exposure (SHSe) is predictive of greater nicotine dependence (ND) and poor smoking cessation (SC) outcomes. SHSe and its impact on ND and SC attempts in people with psychiatric disorders (PD) remain poorly understood. Hence, the objectives of this study were to (1) quantify SHSe, (2) examine the association of SHSe with ND, and (3) assess the association between SHSe and SC among tobacco users with PD.

METHOD

A cross-sectional survey of 118 tobacco users in an inpatient psychiatric facility was conducted. Data on demographics, tobacco use and SHSe history, motivation to quit smoking, ND, and SC attempts were obtained. Participants' environmental and psychosocial sources of and perceived SHSe were described. Multivariate linear regression analyses were used to examine the associations between SHSe and ND, while logistic regression analyses were used to assess the associations between SHSe and SC.

RESULTS

The primary sources of environmental SHSe were from the car (63.6%) and home (51.7%); primary sources of psychosocial SHSe were close friends (67.8%) and parents/grandparents (65.3%); and mean perceived SHSe was 6.2 ( SD = 3.5). Although perceived SHSe was significantly associated with ND (β = .39, p < .0001) in multivariate analyses, no SHSe variable was associated with SC. However, scores on items measuring motivation to quit smoking were associated with SC attempts.

DISCUSSION

Patients with PD reported high levels of SHSe, which was associated with higher ND. Routine screening for SHSe should be implemented as part of health assessments in this population to address ND treatment options. Moreover, targeted interventions and policies should be considered toward reducing SHSe in this vulnerable population.

Acute Response to Cigarette Smoking Assessed in Exhaled Breath Condensate in Patients with Chronic Obstructive Pulmonary Disease and Healthy Smokers

The effect of acute exposure to cigarette smoke (CS) on the respiratory system has been less extensively studied than the long term effects of smoking. The aim of the present study was to evaluate the acute response to CS in smokers suffering from chronic obstructive pulmonary disease (COPD) and in healthy smokers. Nineteen stable COPD patients and 19 young healthy smokers were enrolled. Tumor necrosis factor alpha (TNF-α), IL-1β, and malondialdehyde (MDA) were measured in exhaled breath condensate (EBC) before and 60 min after smoking a cigarette. When pre- and post-CS levels of the evaluated biomarkers were compared, no differences were found in either group. However, the post-CS MDA was significantly greater in healthy smokers than that in COPD patients; 20.41 vs. 16.81 nmol/L, p = 0.01, respectively. Post-CS TNF-α correlated inversely with FEV1/FVC in healthy smokers. We conclude that CS does not acutely increase the EBC concentration of the inflammatory markers either in COPD patients or healthy smokers. The short term CS-induced oxidative stress is higher in young smokers than in COPD patients, which what may indicate a higher susceptibility to CS content of the former.

Antioxidant responses following active and passive smoking of tobacco and electronic cigarettes

CONTEXT

It has been indicated that acute active and passive tobacco cigarette smoking may cause changes on redox status balance that may result in significant pathologies. However, no study has evaluated the effects of active and passive e-cigarette smoking on redox status of consumers.

OBJECTIVE

To examine the acute effects of active and passive e-cigarette and tobacco cigarette smoking on selected redox status markers.

METHODS

Using a randomized single-blind crossover design, 30 participants (15 smokers and 15 nonsmokers) were exposed to three different experimental conditions. Smokers underwent a control session, an active tobacco cigarette smoking session (smoked 2 cigarettes within 30-min) and an active e-cigarette smoking session (smoked a pre-determined number of puffs within 30-min using a liquid with 11 ng/ml nicotine). Similarly, nonsmokers underwent a control session, a passive tobacco cigarette smoking session (exposure of 1 h to 23 ± 1 ppm of CO in a 60 m(3) environmental chamber) and a passive e-cigarette smoking session (exposure of 1 h to air enriched with pre- determined number of puffs in a 60 m(3) environmental chamber). Total antioxidant capacity (TAC), catalase activity (CAT) and reduced glutathione (GSH) were assessed in participants' blood prior to, immediately after, and 1-h post-exposure.

RESULTS

TAC, CAT and GSH remained similar to baseline levels immediately after and 1-h-post exposure (p > 0.05) in all trials.

CONCLUSIONS

Tobacco and e-cigarette smoking exposure do not acutely alter the response of the antioxidant system, neither under active nor passive smoking conditions. Overall, there is not distinction between tobacco and e-cigarette active and passive smoking effects on specific redox status indices.

Increase in oxidative stress levels following welding fume inhalation: a controlled human exposure study

BACKGROUND

Tungsten inert gas (TIG) welding represents one of the most widely used metal joining processes in industry. It has been shown to generate a large majority of particles at the nanoscale and to have low mass emission rates when compared to other types of welding. Despite evidence that TIG fume particles may produce reactive oxygen species (ROS), limited data is available for the time course changes of particle-associated oxidative stress in exposed TIG welders.

METHODS

Twenty non-smoking male welding apprentices were exposed to TIG welding fumes for 60 min under controlled, well-ventilated settings. Exhaled breathe condensate (EBC), blood and urine were collected before exposure, immediately after exposure, 1 h and 3 h post exposure. Volunteers participated in a control day to account for oxidative stress fluctuations due to circadian rhythm. Biological liquids were assessed for total reducing capacity, hydrogen peroxide (H2O2), malondialdehyde (MDA), and 8-hydroxy-2'-deoxyguanosine (8-OHdG) concentrations at each time point. A linear mixed model was used to assess within day and between day differences.

RESULTS

Significant increases in the measured biomarkers were found at 3 h post exposure. At 3 h post exposure, we found a 24 % increase in plasma-H2O2 concentrations ([95%CI: 4 % to 46 %], p = 0.01); a 91 % increase in urinary-H2O2 ([2 % to 258 %], p = 0.04); a 14 % increase in plasma-8-OHdG ([0 % to 31 %], p = 0.049); and a 45 % increase in urinary-8-OHdG ([3 % to 105 %], p = 0.03). Doubling particle number concentration (PNC) exposure was associated with a 22 % increase of plasma-8-OHdG at 3 h post exposure (p = 0.01).

CONCLUSION

A 60-min exposure to TIG welding fume in a controlled, well-ventilated setting induced acute oxidative stress at 3 h post exposure in healthy, non-smoking apprentice welders not chronically exposed to welding fumes. As mass concentration of TIG welding fume particles is very low when compared to other types of welding, it is recommended that additional exposure metrics such as PNC are considered for occupational risk assessments. Our findings highlight the importance of increasing awareness of TIG welding fume toxicity, especially given the realities of welding workplaces that may lack ventilation; and beliefs among interviewed welders that TIG represents a cleaner and safer welding process.

Changes in PH in exhaled breath condensate after specific bronchial challenge test in patients with chronic hypersensitivity pneumonitis: a prospective study

Background

The aim of this study was to investigate the influence of the specific inhalation challenge (SIC) on changes of pH values in exhaled breath condensate (EBC) in patients with hypersensitivity pneumonitis (HP).

Methods

A prospective study of 85 patients with suspected HP, of whom 63 were diagnosed with HP due to exposure to avian or fungal antigens. In all cases, EBC samples were collected before and after completion of the SIC and pH values were determined.

Results

Taken as a whole, patients with HP did not present changes in EBC pH after SIC. However, considering only patients with exposure to molds, those diagnosed with HP had a significantly more acid pH post-SIC than those with another diagnosis (p = 0.011). This fact is not observed in patients exposed to bird’s antigens. A ROC curve showed that a reduction in EBC pH of 0.3 units or more after SIC in patients diagnosed with HP due to exposure to molds had a sensitivity of 30 % (CI: 12.8 to 54.3 %) and a specificity of 100 % (CI: 65.5 to 100 %).

Conclusion

EBC pH may be useful in interpreting SIC results in patients with HP, especially in those patients exposed to molds. Further studies are now required to test the validity of these proposals.

Exhaled Breath Condensate: Technical and Diagnostic Aspects

Purpose. The aim of this study was to evaluate the 30-year progress of research on exhaled breath condensate in a disease-based approach. Methods. We searched PubMed/Medline, ScienceDirect, and Google Scholar using the following keywords: exhaled breath condensate (EBC), biomarkers, pH, asthma, gastroesophageal reflux (GERD), smoking, COPD, lung cancer, NSCLC, mechanical ventilation, cystic fibrosis, pulmonary arterial hypertension (PAH), idiopathic pulmonary fibrosis, interstitial lung diseases, obstructive sleep apnea (OSA), and drugs. Results. We found 12600 related articles in total in Google Scholar, 1807 in ScienceDirect, and 1081 in PubMed/Medline, published from 1980 to October 2014. 228 original investigation and review articles were eligible. Conclusions. There is rapidly increasing number of innovative articles, covering all the areas of modern respiratory medicine and expanding EBC potential clinical applications to other fields of internal medicine. However, the majority of published papers represent the results of small-scale studies and thus current knowledge must be further evaluated in large cohorts. In regard to the potential clinical use of EBC-analysis, several limitations must be pointed out, including poor reproducibility of biomarkers and absence of large surveys towards determination of reference-normal values. In conclusion, contemporary EBC-analysis is an intriguing achievement, but still in early stage when it comes to its application in clinical practice.

Biomarker as a research tool in linking exposure to air particles and respiratory health

Some of the environmental toxicants from air pollution include particulate matter (PM₁₀), fine particulate matter (PM_2.5), and ultrafine particles (UFP). Both short- and long-term exposure could result in various degrees of respiratory health outcomes among exposed persons, which rely on the individuals' health status. Methods. In this paper, we highlight a review of the studies that have used biomarkers to understand the association between air particles exposure and the development of respiratory problems resulting from the damage in the respiratory system. Data from previous epidemiological studies relevant to the application of biomarkers in respiratory system damage reported from exposure to air particles are also summarized. Results. Based on these analyses, the findings agree with the hypothesis that biomarkers are relevant in linking harmful air particles concentrations to increased respiratory health effects. Biomarkers are used in epidemiological studies to provide an understanding of the mechanisms that follow airborne particles exposure in the airway. However, application of biomarkers in epidemiological studies of health effects caused by air particles in both environmental and occupational health is inchoate. Conclusion. Biomarkers unravel the complexity of the connection between exposure to air particles and respiratory health.

Domestic airborne black carbon levels and 8-isoprostane in exhaled breath condensate among children in New York City

BACKGROUND

Exposure to airborne black carbon (BC) has been associated with asthma development, respiratory symptoms and decrements in lung function. However, the mechanism through which BC may lead to respiratory symptoms has not been completely elucidated. Oxidative stress has been suggested as a potential mechanism through which BC might lead to adverse health outcomes. Exhaled breath condensate (EBC) allows for the non-invasive collection of airway lining fluid containing biomarkers of oxidative stress like 8-isoprostane, a stable by-product of lipid peroxidation. Therefore, we sought to characterize the association between domestic airborne BC concentrations and 8-isoprostane in EBC.

MATERIALS AND METHODS

Seven- and eight-year-old children participated in an asthma case-control study in New York City. During home visits, air samples and EBC were collected. Seven day averages of domestic levels of particulate matter <2.5μm (PM2.5), BC and environmental tobacco smoke (ETS) were measured. Urea and 8-isoprostane were measured by liquid chromatography tandem mass spectrometry (LC/MS/MS) in EBC.

RESULTS

In univariate models, PM2.5 and BC, but not ETS, were significantly associated with increases in 8-isoprostane in the EBC (β=0.006 and β=0.106 respectively, p<0.05 for both). These associations remained statistically significant for both PM2.5 and BC after adjustment for covariates. In a co-pollutant model including PM2.5, BC and ETS, only BC remained a statistically significant predictor of 8-isoprostane (p<0.05).

CONCLUSIONS

Our findings suggest the BC fraction of PM might contain exposure relevant to increased oxidative stress in the airways.

Association between exposure to environmental tobacco smoke and biomarkers of oxidative stress among patients hospitalised with acute myocardial infarction

OBJECTIVE

To determine whether exposure to environmental tobacco smoke was associated with oxidative stress among patients hospitalised for acute myocardial infarction.

DESIGN

An existing cohort study of 1,261 patients hospitalised for acute myocardial infarction.

SETTING

Nine acute hospitals in Scotland.

PARTICIPANTS

Sixty never smokers who had been exposed to environmental tobacco smoke (admission serum cotinine ≥3.0 ng/mL) were compared with 60 never smokers who had not (admission serum cotinine ≤0.1 ng/mL).

INTERVENTION

None.

MAIN OUTCOME MEASURES

Three biomarkers of oxidative stress (protein carbonyl, malondialdehyde (MDA) and oxidised low-density lipoprotein (ox-LDL)) were measured on admission blood samples and adjusted for potential confounders.

RESULTS

After adjusting for baseline differences in age, sex and socioeconomic status, exposure to environmental tobacco smoke was associated with serum concentrations of both protein carbonyl (beta coefficient 7.96, 95% CI 0.76, 15.17, p = 0.031) and MDA (beta coefficient 10.57, 95% CI 4.32, 16.81, p = 0.001) but not ox-LDL (beta coefficient 2.14, 95% CI -8.94, 13.21, p = 0.703).

CONCLUSIONS

Exposure to environmental tobacco smoke was associated with increased oxidative stress. Further studies are requires to explore the role of oxidative stress in the association between environmental tobacco smoke and myocardial infarction.