Secondhand smoke exposure, pulmonary function, and cardiovascular mortality

Household air pollution as a determinant of health status: A study on older adults in Siliguri Municipal Corporation, India

Household air pollution (HAP), stemming from solid fuels, traditional cooking practices, and indoor pollutants like incense and mosquito oils, poses severe health risks, particularly for older adults. This study assesses the impact of HAP on self-reported health (SRH) among older adults in Siliguri municipal corporation, India. A cross-sectional survey of 400 older adults used multiple binary logistic regression to analyze HAP's impact on poor SRH. Solid fuel use, traditional cooking, lack of ventilation, and exposure to mosquito oil and family smoking were significantly linked to poorer health. Findings underscore the need for policy measures to reduce HAP through cleaner energy and ventilation improvements, aligning with SDG 7 goals to enhance the health of vulnerable populations.

Locus of control and the long-term effects of parental smoking on mental health

RATIONALE

Few studies take a life course perspective to explain if exposure to second-hand smoke in childhood influences mental health in adulthood. Importantly, no study provides empirical evidence on the pathways through which exposure to second-hand smoke in childhood influences mental health in adulthood. There is also limited evidence on the factors that moderate the relationship between second-hand smoke exposure and mental health. To inform policy, it is important to explore the pathways through which second-hand smoke influences mental health and understand factors that are likely to moderate this relationship.

OBJECTIVES

The objective of this paper is to examine if exposure to parental smoking in childhood influences mental health in adulthood. The study examines general health and smoking status in later life as potential channels and if locus of control (LoC), a personality trait developed in childhood and adolescence, moderates the relationship between exposure to parental smoking in childhood and mental health in adulthood.

METHODS

Using 21 waves of longitudinal data from the Household, Income and Labour Dynamics in Australia (HILDA), the study conducts regression analyses that adjust for the potential effects of confounders and other biases.

RESULTS

The results show that exposure to parental smoking in childhood is associated with a decline in mental health in later life, and that general health status and smoking status in adulthood are channels through which exposure to parental smoking in childhood influences mental health in adulthood. Specifically, those who are exposed to parental smoking in childhood tend to have poorer general health and a higher probability of being smokers in adulthood, both of which negatively impact mental health. The findings point to the moderating role of LoC, such that being more internal on LoC dampens the negative effects of exposure to parental smoking on mental health.

CONCLUSION

The findings from this study lend support to the need to address the long-term implications of behaviours that are harmful to health. The findings also suggest that LoC has implications for an individual's psychological resilience against the negative effects from exposure to parental smoking in childhood.

How Do Active and Passive Cigarette Smokers in Iran Evaluate Their Health? A Sex-Specific Analysis on the Full-Spectrum of Quality of Life

INTRODUCTION

This study aimed to determine the sex-specific effects of active and passive cigarette smoking on the full spectrum of health-related quality of life (HRQoL) among a sizeable adult population.

METHODS

This study was conducted within the Tehran Lipid and Glucose Study (TLGS) framework. Participants included 7478 adults in the last examination of the TLGS. We used a quantile regression model to compare sex-specific HRQoL distributions among non-, current, and passive smokers. Two-step cluster analysis was used to consider the synergic effects of confounder variables.

RESULTS

In men, current smoking was negatively associated with only mental HRQoL in all percentiles of its distribution with a decrease in absolute estimation values from the lowest (5th: β = -6.59, p < .001) to the highest (90th: β=-0.93, p = .027). Also, passive smoking was negatively associated with men's physical HRQoL in the upper percentiles of its distribution (75th: β = -1.12, p = .010; 90th: β = -1.26, p = .016). In women, the current (β = -4.17 to -4.45 for 25th to 90th percentiles) and passive smokers (β = -2.05 to -4.25 for 10th to 90th percentiles) had lower mental HRQoL in the mentioned percentiles. Also, the current smoking had a negative association with the 5th percentile (β = -2.04, p = .008), and a positive association with the 50th (β = 1.94, p < .008) and 75th percentile of physical HRQoL (β = 2.25, p = .004).

CONCLUSIONS

The present study showed the harmful effect of smoking on mental HRQol in all participants. In contrast, the physical effect of smoking was only observed in female active smokers and at the extreme levels of the physical HRQoL spectrum.

IMPLICATIONS

According to the harmful effect of smoking on HRQoL, understanding active and passive smokers' perceptions of how smoking impacts their health is critical for tobacco control programs. Since most previous studies of smoking and HRQoL have mainly focused on the extreme parts or central values of the HRQoL distribution, the use of a multiple regression approach enables the evaluation of other parts of the conditional distribution of the outcome variable. This study demonstrated the prominent effect of smoking on the mental HRQoL as well as the more serious public health burden of passive smoking in women.

Association between secondhand smoke exposure and incident heart failure: The Multi-Ethnic Study of Atherosclerosis (MESA)

AIMS

There are no studies on the association between secondhand smoke (SHS) exposure and incident heart failure (HF). This cohort study aimed to examine the associations of self-reported and urinary cotinine-assessed SHS exposure with incident HF.

METHODS AND RESULTS

This study included 5548 non-active smoking participants aged 45-84 years and free of known cardiovascular diseases and HF at baseline who self-reported SHS exposure time in the Multi-Ethnic Study of Atherosclerosis (MESA) at baseline (2000-2002). A cohort subset of 3376 non-active smoking participants underwent urinary cotinine measurements. HF events were verified by medical records or death certificates and ascertained from baseline through 2019. Multivariable Cox proportional hazards regression analysis was used with adjustment for demographic variables, traditional cardiovascular risk factors, physical activity, tobacco pack-years and medications. During a median follow-up of 17.7 years, 353 and 196 HF events were identified in the self-report cohort and cohort subset, respectively. In the self-report cohort, compared with the SHS unexposed group (0 h/week), the highest tertile of the SHS exposed group (7-168 h/week) was not associated with incident HF (hazard ratio [HR] 0.70, 95% confidence interval [CI] 0.49-1.00; p = 0.052). In contrast, in the cohort subset, participants with detectable urinary cotinine >7.07 ng/ml had a higher risk of incident HF than those with undetectable urinary cotinine ≤7.07 ng/ml (HR 1.45, 95% CI 1.03-2.06; p = 0.034). There were no significant heterogeneities in HF risk by age, sex, race/ethnicity, or past smoking status.

CONCLUSION

Secondhand smoke exposure reflected by modestly increased urinary cotinine (>7.07 ng/ml) rather than self-report in non-active smokers was associated with a 40-50% higher risk of any HF event.

Effect of twice daily inhaled albuterol on cardiopulmonary exercise outcomes, dynamic hyperinflation, and symptoms in secondhand tobacco-exposed persons with preserved spirometry and air trapping: a randomized controlled trial

BACKGROUND

In tobacco-exposed persons with preserved spirometry (active smoking or secondhand smoke [SHS] exposure), air trapping can identify a subset with worse symptoms and exercise capacity. The physiologic nature of air trapping in the absence of spirometric airflow obstruction remains unclear. The aim of this study was to examine the underlying pathophysiology of air trapping in the context of preserved spirometry and to determine the utility of bronchodilators in SHS tobacco-exposed persons with preserved spirometry and air trapping.

METHODS

We performed a double-blinded placebo-controlled crossover randomized clinical trial in nonsmoking individuals at risk for COPD due to exposure to occupational SHS who had preserved spirometry and air trapping defined as either a residual volume-to-total lung capacity ratio (RV/TLC) > 0.35 or presence of expiratory flow limitation (EFL, overlap of tidal breathing on maximum expiratory flow-volume loop) on spirometry at rest or during cardiopulmonary exercise testing (CPET). Those with asthma or obesity were excluded. Participants underwent CPET at baseline and after 4-week trials of twice daily inhalation of 180 mcg of albuterol or placebo separated by a 2-week washout period. The primary outcome was peak oxygen consumption (VO2) on CPET. Data was analyzed by both intention-to-treat and per-protocol based on adherence to treatment prescribed.

RESULTS

Overall, 42 participants completed the entire study (66 ± 8 years old, 91% female; forced expiratory volume in 1 s [FEV1] = 103 ± 16% predicted; FEV1 to forced vital capacity [FVC] ratio = 0.75 ± 0.05; RV/TLC = 0.39 ± 0.07; 85.7% with EFL). Adherence was high with 87% and 93% of prescribed doses taken in the treatment and placebo arms of the study, respectively (P = 0.349 for comparison between the two arms). There was no significant improvement in the primary or secondary outcomes by intention-to-treat or per-protocol analysis. In per-protocol subgroup analysis of those with RV/TLC > 0.35 and ≥ 90% adherence (n = 27), albuterol caused an improvement in peak VO2 (parameter estimate [95% confidence interval] = 0.108 [0.014, 0.202]; P = 0.037), tidal volume, minute ventilation, dynamic hyperinflation, and oxygen-pulse (all P < 0.05), but no change in symptoms or physical activity.

CONCLUSIONS

Albuterol may improve exercise capacity in the subgroup of SHS tobacco-exposed persons with preserved spirometry and substantial air trapping. These findings suggest that air trapping in pre-COPD may be related to small airway disease that is not considered significant by spirometric indices of airflow obstruction.

Particle Exposure Hazards of Visiting Outdoor Smoking Areas for Patients with Asthma or COPD Even in EU Countries with Comprehensive Smokefree Laws

Smokefree laws are intended to protect against second-hand smoke (SHS) in outdoor areas. We examined if exposure to PM2.5 particles in outdoor smoking areas changed breathing rates in 60 patients with asthma (n = 30) or with COPD (n = 30), in an open, non-randomised, interventional study model in Czechia, Ireland and Spain. The patients wore a PM2.5 particle monitor (AirSpeck) and a breath monitor (RESpeck) for 24 h to determine changes in breathing rates (Br) at rest and during a visit to an outside smoking area. Spirometry and breath CO were measured before and the day after visiting an outdoor smoking area. The PM2.5 levels at the 60 venues were highly variable, ranging from ≥2000 µg/m3 (in 4 premises) to ≤10 µg/m3 (in 3 premises, which had only a single wall in the structure). At 39 venues, the mean PM 2.5 levels were ≥25 µg/m3. The breathing rate changed significantly in 57 of the 60 patients, resulting in an increase in some patients and a decrease in others. Comprehensive smokefree laws were ineffective in protecting asthma and COPD patients from exposure to high levels of SHS in outside areas of pubs and terraces, which should be avoided by these patients. These findings also support the extension of smokefree laws to outside areas.

Nationwide indoor smoking ban and impact on smoking behaviour and lung function: a two-population natural experiment

INTRODUCTION

Many countries have implemented indoor smoking bans over the past two decades. Although smoking bans have been shown to reduce cardiovascular outcomes, little is known about their impact on respiratory health. This study investigated the impact of a nationwide indoor smoking ban on smoking behaviour and lung function.

METHODS

We used repeated cross-sectional data from two large cohorts of the general population comprising 31 807 Swiss and 62 093 Danish adults. We compared associations between smoking ban and smoking prevalence and prebronchodilator lung function trends in Denmark (indoor smoking ban introduced in 2007) and Switzerland (indoor smoking ban introduced in 2010) from 2005 to 2010 using a quasi-experimental study design. We performed difference-in-difference analyses with linear regression models adjusted for age, sex, weight and height.

RESULTS

Denmark had a stronger decrease in active smokers compared with Switzerland. Also, forced expiratory volume in the first second was higher in Danish adults than in Swiss adults: 26 mL (95% CI 2.4 to 49) 1 year, 88 mL (65 to 112) 2 years, and 74 mL (51 to 98) 3 years after smoking ban implementation. Correspondingly, forced vital capacity was higher in Danish adults compared with Swiss adults (80 mL (50 to 109) after 1 year and 126 mL (97 to 155) after two and 3 years). Improvements were observed in both never-smokers and ever-smokers, most pronounced in ever-smokers.

CONCLUSIONS

Nationwide indoor smoking ban is associated with less smoking and improved lung function in the general population. Implementing an indoor smoking ban can improve lung function by influencing smoking behaviour and reducing secondhand smoke.

HRCT findings in secondhand smokers with respiratory symptoms

PURPOSE

The present study aims to investigate the occurrence and severity of HRCT abnormalities in symptomatic never-smokers, passively exposed to cigarette smoke.

MATERIALS AND METHODS

A total of 135 never-smokers with respiratory symptoms, without underlying lung disease, underwent paired inspiratory-expiratory HRCT and completed the secondhand smoking (SHS) exposure scale questionnaire. Individuals passively exposed to tobacco consisted the secondhand smoking group (SHS group) (n = 68); the remaining 67 controls were never exposed to SHS. Statistical analysis was performed using the Kolmogorov-Smirnov, x² and Pearson Point-Biserial correlation tests. P < 0.05 was statistically significant.

RESULTS

HRCT findings in SHS group included bronchial wall thickening (98.5%), mild cylindrical bronchiectasis (44%), ground-glass opacities (17.6%), and mosaic attenuation pattern (53%). Air trapping occurred in 65% of expiratory scans. Differences in occurrence of findings between SHS group participants and controls were statistically significant (p < 0.0001). There was significant correlation between exposure to tobacco smoke in hours/day and in number of cigarettes/day and the presence of mosaic attenuation pattern, ground-glass opacities, cylindrical bronchiectasis and air trapping, respectively (p < 0.05). Cumulative SHS exposure in years was also strongly correlated with the presence of ground-glass opacities, mosaic attenuation pattern, cylindrical bronchiectasis, and air trapping, as well as with the frequency of respiratory symptoms (p < 0.05).

CONCLUSION

HRCT findings attributed to SHS are mostly related to airway involvement and are correlated with the duration and grade of exposure to environmental tobacco smoke. SHS followed by lifestyle adjustments should be considered in symptomatic non-smokers with such HRCT findings.

Smoke-Free Policies and 30-Day Mortality Rates for Chronic Obstructive Pulmonary Disease

BACKGROUND

Smoke-free policies have been shown to impact 30-day readmission rates due to chronic obstructive pulmonary disease (COPD) among adults aged ≥65 years. However, little is known about the association between smokefree policies and 30-day mortality rates for COPD. Therefore, we investigated the association between comprehensive smoke-free policies and 30-day mortality rates for COPD.

METHODS

We used a cross-sectional study design and retrospectively examined risk-adjusted 30-day mortality rates for COPD across US hospitals in 1171 counties. Data were sourced from Centers for Medicare and Medicaid Services (CMS) Hospital Value-Based Purchasing (HVBP) Program, American Hospital Association (AHA) Annual Surveys, US Census Bureau Current Population Survey, and US Tobacco Control Laws Database from the American Nonsmokers' Rights Foundation (ANRF). Data were averaged at the county level for years 2015-2018. Hierarchical Poisson models adjusted for differences in hospital characteristics and accounted for the clustering of hospitals within a county were used.

RESULTS

Our findings show a consistent association between stronger smoke-free policies and a reduction in COPD mortality. When evaluating smoke-free policy, county characteristics, and hospital characteristics individually, we found that counties with full coverage or partial coverage had a reduced incidence rate of COPD mortality compared to no coverage counties. After adjusting for the county and hospital characteristics, counties with full coverage of smoke-free policies had a reduced rate of 30-day COPD mortality (adjusted incidence rate ratio [IRR]: 0.87, 95% CI: 0.79, 0.96) compared to counties with no policy coverage.

CONCLUSION

Comprehensive smoke-free policies are associated with a reduction in 30-day mortality following hospital admission for COPD. Partial smoke-free legislation is an insufficient preventative measure. These findings have strong implications for hospital policy-makers, suggesting that policy interventions to reduce COPD-related 30-day mortality should include implementing smoke-free policies and public health policy-makers to incentivize comprehensive smokefree policies.

Secondhand tobacco smoke exposure, urine cotinine, and risk of incident atrial fibrillation: The multi-ethnic study of atherosclerosis

BACKGROUND

Secondhand tobacco smoke (SHS) exposure may reduce heart rate variability and lead to atrial fibrillation (AF); however prior study findings have not been confirmed using objective measures for both SHS and AF events.

METHODS

We prospectively examined the association between SHS exposure and incident AF in 5731 participants, ages of 45-84 years and free of known AF and other cardiovascular diseases (CVD) at baseline (2000-2002), who were followed through 2015 in the Multi-Ethnic Study of Atherosclerosis (MESA). SHS weekly exposure time was identified by self-report. Urine cotinine was collected in a cohort subset of 3237 current non-smoking cohort participants. AF events were identified using Medicare claims, hospital records, and 12‑lead electrocardiographic findings. A multivariable Cox proportional hazards regression analysis was used with simultaneous adjustment for demographic factors, educational level, health insurance status, active smoking status, tobacco pack-years, traditional CVD risk factors, depressive symptoms and medications.

RESULTS

During a median follow-up of 14.0 years, 856 and 452 AF events were identified in the overall and the cohort subset, respectively. No association of SHS exposure time or urine cotinine with incident AF was observed. However, a higher AF risk with greater urine cotinine (8.53-442.0 ng/mL) compared with lower urine cotinine (≤7.07 ng/mL) was observed in never smokers [hazard ratios (HR) and 95% confidence intervals: 1.60 (1.16, 2.19)], but not in former smokers [HR: 0.88 (0.63, 1.23)] (p-value for multiplicative interaction: 0.009 and for additive interaction: 0.017, respectively).

CONCLUSION

Objectively measured greater SHS exposure expressed by urine cotinine might be associated with 1.6-fold higher risk of incident AF in never smokers.

Remote exposure to secondhand tobacco smoke is associated with lower exercise capacity through effects on oxygen pulse, a proxy of cardiac stroke volume

BACKGROUND

Past exposure to secondhand tobacco smoke (SHS) is associated with exercise limitation. Pulmonary factors including air trapping contribute to this limitation but the contribution of cardiovascular factors is unclear.

OBJECTIVE

To determine the contribution of cardiovascular mechanisms to SHS-associated exercise limitation.

METHODS

We examined the cardiovascular responses to maximum-effort exercise in 245 never-smokers with remote, prolonged occupational exposure to SHS and no known history of cardiovascular disease. We estimated the contribution of oxygen-pulse (proxy for cardiac stroke volume) and changes in systolic blood pressures (SBP), diastolic blood pressures and heart rate (HR) towards exercise capacity, and examined whether the association of SHS with exercise capacity was mediated through these variables.

RESULTS

At peak exercise (highest workload completed (WattsPeak)=156±46 watts (135±33 %predicted)), oxygen consumption and oxygen-pulse (O2-PulsePeak) were 1557±476 mL/min (100±24 %predicted) and 11.0±3.0 mL/beat (116±25 %predicted), respectively, with 29% and 3% participants not achieving their predicted normal range. Oxygen saturation at peak exercise was 98%±1% and remained >93% in all participants. Sixty-six per cent showed hypertensive response to exercise. In models adjusted for covariates, WattsPeak was associated directly with O2-PulsePeak, HRPeak and SBPPeak and inversely with SHS, air trapping (residual volume/total lung capacity) and rise of SBP over workload (all p<0.01). Moreover, SHS exposure association with WattsPeak was substantially (41%) mediated through its effect on O2-PulsePeak (p=0.038). Although not statistically significant, a considerable proportion (36%) of air trapping effect on WattsPeak seemed to be mediated through O2-PulsePeak (p=0.078). The likelihood of having baseline respiratory symptoms (modified Medical Research Council score ≥1) was associated with steeper rise in SBP over workload (p<0.01).

CONCLUSION

In a never-smoker population with remote exposure to SHS, abnormal escalation of blood pressure and an SHS-associated reduction in cardiac output contributed to lower exercise capacity.

Burden of disease from second-hand tobacco smoke exposure at home among adults from European Union countries in 2017: an analysis using a review of recent meta-analyses

Smoke-free legislation reduced second-hand smoke (SHS) exposure in public places, and indirectly promoted private smoke-free settings. Nevertheless, a large proportion of adults is still exposed to SHS at home. The aim of this paper is to quantify the burden of disease due to home SHS exposure among adults in the 28-European Union (EU) countries for year 2017. The burdens by gender from lung cancer, chronic obstructive pulmonary disease (COPD), breast cancer, ischemic heart disease (IHD), stroke, asthma, and diabetes were estimated in an original research analysis using the comparative risk assessment method. Relative risks of death/diseases by gender for adults exposed to SHS at home compared to not exposed ones were estimated updating existing meta-analyses. Prevalence of home SHS exposure by gender was estimated using a multiple imputation procedure based on Eurobarometer surveys. Data on mortality and disability adjusted life years (DALYs) were obtained from the Global Burden of Disease, Injuries and Risk Factors Study. In 2017, 526,000 DALYs (0.36% of total DALYs) and 24,000 deaths (0.46% of total deaths) were attributable to home SHS exposure in the 28-EU countries, mainly from COPD and IHD. South-Eastern EU countries showed the highest burden, with proportion of DALYs/deaths attributable to SHS exposure on total higher than 0.50%/0.70%, whereas northern EU-countries showed the lowest burden, with proportions of DALYs/deaths lower than 0.25%/0.34%. The burden from SHS exposure is still significant in EU countries. More could be done to raise awareness of the health risks associated with SHS exposure at home.

Biomarker-assessed passive smoking in relation to cause-specific mortality: pooled data from 12 prospective cohort studies comprising 36 584 individuals

AIMS

While investigators have typically quantified the health risk of passive (secondhand) smoking by using self-reported data, these are liable to measurement error. By pooling data across studies, we examined the prospective relation of a biochemical assessment of passive smoking, salivary cotinine, with mortality from a range of causes.

METHODS

We combined data from 12 cohort studies from England and Scotland initiated between 1998 and 2008. A total of 36 584 men and women aged 16-85 years of age reported that they were non-smoking at baseline, provided baseline salivary cotinine and consented to mortality record linkage.

RESULTS

A mean of 8.1 years of mortality follow-up of 36 584 non-smokers (16 792 men and 19 792 women) gave rise to 2367 deaths (775 from cardiovascular disease, 779 from all cancers and 289 from smoking-related cancers). After controlling for a range of covariates, a 10 ng/mL increase in salivary cotinine was related to an elevated risk of total (HRs; 95% CI) (1.46; 1.16 to 1.83), cardiovascular disease (1.41; 0.96 to 2.09), cancer (1.49; 1.00 to 2.22) and smoking-related cancer mortality (2.92; 1.77 to 4.83).

CONCLUSIONS

Assessed biomedically, passive smoking was a risk factor for a range of health outcomes known to be causally linked to active smoking.

Metabolomics Identifies Novel Blood Biomarkers of Pulmonary Function and COPD in the General Population

Determination of metabolomic signatures of pulmonary function and chronic obstructive pulmonary disease (COPD) in the general population could aid in identification and understanding of early disease processes. Metabolome measurements were performed on serum from 4742 individuals (2354 African-Americans and 1529 European-Americans from the Atherosclerosis Risk in Communities study and 859 Europeans from the Cooperative Health Research in the Region of Augsburg study). We examined 368 metabolites in relation to cross-sectional measures of forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), their ratio (FEV1/FVC) and COPD using multivariable regression followed by meta-analysis. At a false discovery rate of 0.05, 95 metabolites were associated with FEV1 and 100 with FVC (73 overlapping), including inverse associations with branched-chain amino acids and positive associations with glutamine. Ten metabolites were associated with FEV1/FVC and seventeen with COPD (393 cases). Enriched pathways of amino acid metabolism were identified. Associations with FEV1 and FVC were not driven by individuals with COPD. We identified novel metabolic signatures of pulmonary function and COPD in African and European ancestry populations. These may allow development of biomarkers in the general population of early disease pathogenesis, before pulmonary function has decreased to levels diagnostic for COPD.

Lung volumes identify an at-risk group in persons with prolonged secondhand tobacco smoke exposure but without overt airflow obstruction

Introduction

Exposure to secondhand smoke (SHS) is associated with occult obstructive lung disease as evident by abnormal airflow indices representing small airway disease despite having preserved spirometry (normal forced expiratory volume in 1 s-to-forced vital capacity ratio, FEV₁/FVC). The significance of lung volumes that reflect air trapping in the presence of preserved spirometry is unclear.

Methods

To investigate whether lung volumes representing air trapping could determine susceptibility to respiratory morbidity in people with SHS exposure but without spirometric chronic obstructive pulmonary disease, we examined a cohort of 256 subjects with prolonged occupational SHS exposure and preserved spirometry. We elicited symptom prevalence by structured questionnaires, examined functional capacity (maximum oxygen uptake, VO_2max) by exercise testing, and estimated associations of those outcomes with air trapping (plethysmography-measured residual volume-to-total lung capacity ratio, RV/TLC), and progressive air trapping with exertion (increase in fraction of tidal breathing that is flow limited on expiration during exercise (per cent of expiratory flow limitation, %EFL)).

Results

RV/TLC was within the predicted normal limits, but was highly variable spanning 22%±13% and 16%±8% across the increments of FEV₁/FVC and FEV₁, respectively. Respiratory complaints were prevalent (50.4%) with the most common symptom being ≥2 episodes of cough per year (44.5%). Higher RV/TLC was associated with higher OR of reporting respiratory symptoms (n=256; r²=0.03; p=0.011) and lower VO_2max (n=179; r²=0.47; p=0.013), and %EFL was negatively associated with VO_2max (n=32; r²=0.40; p=0.017).

Conclusions

In those at risk for obstruction due to SHS exposure but with preserved spirometry, higher RV/TLC identifies a subgroup with increased respiratory symptoms and lower exercise capacity.

Female non-smokers' environmental tobacco smoking exposure by public transportation mode

Background

This study aimed to analyze environmental tobacco smoking exposure in female nonsmokers by public transportation mode using representative data of Koreans.

Methods

Data from the Second Korean National Environmental Health Survey (2012–2014) were analyzed. Urine cotinine was analyzed by public transport behavior, secondhand smoke exposure, socioeconomic factors, and health-related factors. Participants were 1322 adult females; those with the top 75% urine cotinine concentrations were assigned to the high exposure group. A logistic regression analysis was performed considering appropriate weights and stratification according to the sample design of the Second Korean National Environmental Health Survey.

Results

The geometric mean of urine cotinine concentrations differed according to public transportation modes: subway (1.66 μg/g creatinine) bus (1.77 μg/g creatinine), and taxi (1.94 μg/g creatinine). The odds ratio [OR] was calculated for the high exposure group. The OR of the taxi (2.39; 95% confidence interval, 1.00–5.69) was statistically significantly higher than the subway value (reference), and marginally significant after adjusted with life style, sociodemographic factors and involuntary smoking frequency (2.42, 95% confidence interval, 0.97–6.04).

Conclusions

The odds ratio of passengers who mainly used taxis was marginally significantly higher than those of passengers who used subways and buses after adjusted with life style and sociodemographic factors. Implementation of supplementary measures and further studies on exposure to environmental tobacco smoking in taxis are warranted.

Indoor environmental factors associated with pulmonary function among adults in an acid rain-plagued city in Southwest China

OBJECTIVE

To assess the association of indoor environmental risk factors with respiratory function among adults in an acid rain-plagued city in China where coal use is frequent.

METHODS

The subjects were randomly selected in the winter season. Information on selected home environmental factors was collected through administered questionnaires. Additionally, pulmonary function tests, including Forced Vital Capacity (FVC), Forced Expiratory Volume in 1 s (FEV₁), FEV₁/FVC and Peak Expiratory Flow Rate (PEFR) were also performed in participants.

RESULTS

This study showed that, among a variety of risk factors, coal fuel use, cooking oil fumes and active and passive smoking exposure together with asthma in childhood were important factors for deterioration of pulmonary function among adults in the winter season (p < 0.05). Additionally, subjects whose kitchen was located in the living room or bedroom, who opened their windows only occasionally or never, who noted the presence of cooking oil fumes and pests, whose bedroom was shared by 3 or more residents and who kept pets tended to exhibit lower values of FVC, FEV₁ and PEFR values compared with non-exposed counterparts (p < 0.05).

CONCLUSIONS

This study demonstrated impaired pulmonary function among adults who were exposed to indoor risk factors, such as coal fires and cigarette smoking compared to non-users in the winter season and emphasizes the need for public health efforts to decrease exposure to indoor air pollution.

Gender Differences in the Association of Individual and Contextual Exposures with Lung Function in a Rural Canadian Population

INTRODUCTION

To investigate the association of individual and contextual exposures with lung function by gender in rural-dwelling Canadians.

METHODS

A cross-sectional mail survey obtained completed questionnaires on exposures from 8263 individuals; a sub-sample of 1609 individuals (762 men, 847 women) additionally participated in clinical lung function testing. The three dependent variables were forced expired volume in one second (FEV₁), forced vital capacity (FVC), and FEV₁/FVC ratio. Independent variables included smoking, waist circumference, body mass index, indoor household exposures (secondhand smoke, dampness, mold, musty odor), occupational exposures (grain dust, pesticides, livestock, farm residence), and socioeconomic status. The primary analysis was multiple linear regression, conducted separately for each outcome. The potential modifying influence of gender was tested in multivariable models using product terms between gender and each independent variable.

RESULTS

High-risk waist circumference was related to reduced FVC and FEV₁ for both genders, but the effect was more pronounced in men. Greater pack-years smoking was associated with lower lung function values. Exposure to household smoke was related to reduced FEV₁, and exposure to livestock, with increased FEV₁. Lower income adequacy was associated with reduced FVC and FEV₁.

CONCLUSION

High-risk waist circumference was more strongly associated with reduced lung function in men than women. Longitudinal research combined with rigorous exposure assessment is needed to clarify how sex and gender interact to impact lung function in rural populations.

Affecting Factors of Secondhand Smoke Exposure in Korea: Focused on Different Exposure Locations

Exposure to secondhand smoke (SHS) not only can cause serious illness, but is also an economic and social burden. Contextual and individual factors of non-smoker exposure to SHS depend on location. However, studies focusing on this subject are lacking. In this study, we described and compared the factors related to SHS exposure according to location in Korea. Regarding individual factors related to SHS exposure, a common individual variable model and location-specific variable model was used to evaluate SHS exposure at home/work/public locations based on sex. In common individual variables, such as age, and smoking status showed different relationships with SHS exposure in different locations. Among home-related variables, housing type and family with a single father and unmarried children showed the strongest positive relationships with SHS exposure in both males and females. In the workplace, service and sales workers, blue-collar workers, and manual laborers showed the strongest positive association with SHS exposure in males and females. For multilevel analysis in public places, only SHS exposure in females was positively related with cancer screening rate. Exposure to SHS in public places showed a positive relationship with drinking rate and single-parent family in males and females. The problem of SHS embodies social policies and interactions between individuals and social contextual factors. Policy makers should consider the contextual factors of specific locations and regional and individual context, along with differences between males and females, to develop effective strategies for reducing SHS exposure.

Environmental Tobacco Smoke and Atrial Fibrillation: The REasons for Geographic And Racial Differences in Stroke (REGARDS) Study

OBJECTIVE

This study examines the association between environmental tobacco smoke (ETS) exposure and atrial fibrillation (AF).

METHODS

We examined the cross-sectional association between ETS exposure and AF in 12,021 participants (mean age: 65 ± 9.9 years; 60% women; 40% blacks) from the REasons for Geographic And Racial Differences in Stroke study who self-identified as never smokers between 2003 and 2007.

RESULTS

A total of 2503 (21%) participants reported ETS exposure. In a multivariate logistic regression model adjusted for sociodemographics and potential confounders, ETS exposure was significantly associated with AF (odds ratio = 1.27, 95% confidence interval = 1.08, 1.50).

CONCLUSIONS

Our findings suggest that the harmful effects of ETS exposure extend to sustained arrhythmias such as AF.

Understanding the impact of second-hand smoke exposure on clinical outcomes in participants with COPD in the SPIROMICS cohort

BACKGROUND

Second-hand smoke (SHS) exposure has been linked to the development of and morbidity from lung disease. We sought to advance understanding of the impact of SHS on health-related outcomes in individuals with COPD.

METHODS

Among the participants with COPD in SPIROMICS, recent SHS exposure was quantified as (1) hours of reported exposure in the past week or (2) reported living with a smoker. We performed adjusted regression for SHS with outcomes, testing for interactions with gender, race, smoking and obesity.

RESULTS

Of the 1580 participants with COPD, 20% reported living with a smoker and 27% reported exposure in the past week. Living with a smoker was associated with worse St George's Respiratory Questionnaire score (SGRQ, β 3.10; 95% CI 0.99 to 5.21), COPD Assessment Test score (β 1.43; 95% CI 0.52 to 2.35) and increased risk for severe exacerbations (OR 1.51, 95% CI 1.04 to 2.17). SHS exposure in the past week was associated with worse SGRQ (β 2.52; 95% CI 0.47 to 4.58), nocturnal symptoms (OR 1.58; 95% CI 1.19 to 2.10), wheezing (OR 1.34; 95% CI 1.02 to 1.77), chronic productive cough (OR 1.77; 95% CI 1.33 to 2.35) and difficulty with cough and sputum (Ease of Cough and Sputum scale, β 0.84; 95% CI 0.42 to 1.25). SHS was associated with increased airway wall thickness on CT but not emphysema. Active smokers, obese individuals and individuals with less severe airflow obstruction also had higher susceptibility to SHS for some outcomes.

CONCLUSION

Individuals with COPD, including active smokers, have significant SHS exposure, associated with worse outcomes and airway wall thickness. Active smokers and obese individuals may have worse outcomes associated with SHS.

TRIAL REGISTRATION NUMBER

NCT01969344 (clinicaltrials.gov).

Secondhand smoke exposure (SHS) and health-related quality of life (HRQoL) in Chinese never smokers in Hong Kong

OBJECTIVE

The evidence on the effect of secondhand smoke (SHS) on Health Related Quality of Life (HRQoL) is limited. We examined the relation between SHS and HRQoL among Chinese in Hong Kong.

METHODS

Adult never smokers from a probability sample of three cross-sectional waves (2010, 2012, 2013) of The Hong Kong Family and Health Information Trends Survey who completed the Cantonese-version of Short-Form 12 Health Survey Questionnaire (SF12v2) were included in the data analysis conducted in 2014. Models were used to examine associations of SHS with SF12 domains and summary scores of Physical (PCS12) and Mental Component (MCS12) with subgroups analysis by SHS locations.

RESULTS

After adjustments, SHS was associated with lower scores on all SF12 domains except physical functioning. PCS12 (regress coefficient=-0.76, 95% CI -1.34 to -0.17) and MCS12 (regress coefficient=-1.35, 95% CI -2.06 to -0.64) were lower in those with SHS exposure than those non-exposed. Those exposed to SHS in outdoor public places had lower scores on most SF12 domains and PSC12 and MCS12. SHS exposure in one's home and workplace was associated with lower scores on role physical, body pain and role emotional while SHS exposure in friends' homes was additionally associated with lower social functioning and mental health scores. Lower MCS12 was associated with SHS exposure at all locations except one's home.

CONCLUSIONS

Our study showed that SHS exposure, particularly in outdoor public places, was associated with decreased HRQoL. It can provide new evidence for stronger smoke-free policies on public places and promoting smoke-free homes.

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.

Air nicotine levels in public places in ahmedabad, India: before and after implementation of the smoking ban

Aim:

To compare air nicotine levels in public places in Ahmedabad, India, before (June 2008) and after (January, 2010) the implementation of a comprehensive smoking ban which was introduced in October 2008.

Materials and Methods:

Air nicotine concentrations were measured by sampling of vapor-phase nicotine using passive monitors. In 2008 (baseline), monitors were placed for 5-7 working days in 5 hospitals, 10 restaurants, 5 schools, 5 government buildings, and 10 entertainment venues, of which 6 were hookah bars. In 2010 (follow-up), monitors were placed in 35 similar venues for the same duration.

Results:

Comparison of the overall median nicotine concentration at baseline (2008) (0.06 μg/m³ Interquartile range (IQR): 0.02-0.22) to that of follow-up (2010) (0.03 μg/m³ IQR: 0.00-0.13), reflects a significant decline (% decline = 39.7, P = 0.012) in exposure to second-hand smoke (SHS). The percent change in exposure varied by venue-type. The most significant decrease occurred in hospitals, from 0.04 μg/m³ at baseline to concentrations under the limit of detection at follow-up (%decline = 100, P < 0.001). In entertainment venues, government offices, and restaurants, decreases in SHS exposure also appeared evident. However, in hookah bars, air nicotine levels appeared to increase (P = 0.160).

Conclusion:

Overall, SHS exposure was significantly reduced in public places after the smoke-free legislation came into force. However, nicotine concentrations were still detected in most of the venues indicating imperfect compliance with the comprehensive ban.

Acute systemic accumulation of acrolein in mice by inhalation at a concentration similar to that in cigarette smoke

Cigarette smoke is an important environmental factor associated with a wide array of public health concerns. Acrolein, a component of tobacco smoke and a known toxin to various cell types, may be a key pathological factor mediating the adverse effects linked with tobacco smoke. Although acrolein is known to accumulate in the respiratory system after acute nasal exposure, it is not clear if it accumulates systemically, and less is known in the nervous system. The aim of this study was to assess the degree of acrolein accumulation in the circulation and in the spinal cord following acute acrolein inhalation in mice. Using a laboratory-fabricated inhalation chamber, we found elevated urinary 3-HPMA, an acrolein metabolite, and increased acrolein adducts in the spinal cord after weeks of nasal exposure to acrolein at a concentration similar to that in tobacco smoke. The data indicated that acrolein is absorbed into the circulatory system and some enters the nervous system. It is expected that these findings may facilitate further studies to probe the pathological role of acrolein in the nervous system resulting from smoke and other external sources.

Dyspnea as an independent predictor of mortality

BACKGROUND AND AIM

Dyspnea is a common and easily elicited presenting complaint in patients seen by physicians who evaluate and take care of chronic respiratory disorders. Although dyspnea is subjective and tends to increase with age or reduced lung function, it appears to be reproducible as a symptom and often signifies serious underlying disease.

METHODS

Systematic review of longitudinal studies with dyspnea as the exposure and mortality as the outcome; age, smoking and lung function had to be controlled for to be included in the review. In addition, a minimum sample size at baseline of 500 subjects was required for each study.

RESULTS

From over 3000 potential references, 10 longitudinal studies met all criteria and were included. All 10 studies suggested that dyspnea was an independent predictor of mortality with point estimates by odds ratio, rate ratio or hazard ratios ranging from 1.3 up to 2.9-fold greater than baseline. All 10 studies had actual or implied 95% confidence interval bands greater than the null value of one.

CONCLUSION

Dyspnea, a symptom, predicts mortality and is a proxy for underlying diseases, most often of heart and lung. Therefore, chronic dyspnea needs to be evaluated as to etiology to allow for treatment to minimize morbidity and mortality when possible.

Tobacco smoke exposure in pulmonary arterial and thromboembolic pulmonary hypertension

BACKGROUND

Animal studies and data from a single-center study suggest that tobacco smoke exposure may be a risk factor for precapillary pulmonary hypertension (PH).

OBJECTIVE

We aimed to survey tobacco smoke exposure in a large PH collective and to compare it with epidemiological data from healthy subjects.

METHODS

This is an international, multicenter, case-control study including patients with pulmonary arterial and chronic thromboembolic PH. All patients were asked specific questions about tobacco smoke exposure. Healthy controls were retrieved from the Swiss Health Survey (n = 18,747).

RESULTS

Overall (n = 472), 49% of PH patients were smokers and there was a clear sex difference (women 37%, men 71%). Significantly more PH men were smokers compared with healthy controls, whereas less PH women were ever active smokers. However, 50% of the non-smoking PH women were exposed to secondhand smoke, leading to a significantly higher number of tobacco smoke-exposed individuals compared to healthy controls. PH smokers were significantly younger compared to those not exposed.

CONCLUSION

Active and environmental tobacco smoke exposure is common in PH. The higher prevalence of male PH smokers, the higher exposure to environmental tobacco smoke in PH women compared to healthy controls and the lower age at PH diagnosis in smokers may indicate a pathogenic role of tobacco smoke exposure in PH.

The impact of smoke-free laws on asthma discharges: a multistate analysis

OBJECTIVES

This is the first, to my knowledge, multistate, county-level analysis of Healthcare Cost and Utilization Project state inpatient data to examine the relationship between smoke-free laws and asthma discharges.

METHODS

I used treatment and control groups to examine the effects of state and county or city smoke-free laws separately and together (2002-2009). I compared quarterly county-level discharge rates before and after the implementation of 12 state smoke-free laws, accounting for counties with preexisting county or city smoke-free laws and using the data from 5 states without state smoke-free laws as a control group. I used difference-in-differences models, controlling for year and state fixed effects, state cigarette taxes, seasonality, and numerous county-level factors.

RESULTS

I observed statistically significant reductions in asthma discharges after the implementation of county smoke-free laws but no statistically significant effect of state laws besides the effect of county laws or of state laws alone. There was also no statistically significant effect of any smoke-free law on appendicitis discharges.

CONCLUSIONS

It may be unwise to pursue state smoke-free laws where they have yet to pass; rather, efforts might be better focused at the local level, where there is evidence of a significant impact.

A cross-sectional study of secondhand smoke exposure and respiratory symptoms in non-current smokers in the U.S. trucking industry: SHS exposure and respiratory symptoms

BACKGROUND

Previous studies have suggested associations of adult exposures to secondhand smoke (SHS) with respiratory symptoms, but no study has focused on blue-collar industrial environments. We assessed the association between SHS and respiratory symptoms in 1,562 non-current smoking U.S. trucking industry workers.

METHODS

Information on SHS exposure and respiratory health was obtained by questionnaire. Multiple logistic regression analyses were used to assess the associations of recent and lifetime exposures to SHS with chronic phlegm, chronic cough, and any wheeze, defined by American Thoracic Society criteria.

RESULTS

In analyses adjusted for age, gender, race, childhood SHS exposure, former smoking, pack-years of smoking and years since quitting, body mass index, job title, region of the country, and urban residence, recent exposures to SHS were associated with all three respiratory symptoms (odds ratio (OR) = 1.46; 95% confidence interval (CI) = 1.00-2.13) for chronic cough, 1.55 (95% CI = 1.08-2.21) for chronic phlegm, and 1.76 (95% CI = 1.41-2.21) for any wheeze). Workplace exposure was the most important recent exposure. Childhood exposure to SHS was also associated with all three symptoms, but only statistically significantly for chronic phlegm (OR = 1.84; 95% CI = 1.24-2.75). Additional years of living with a smoker were associated with an increased risk, but there was no evidence of a dose-response, except for chronic phlegm.

CONCLUSIONS

In this group of trucking industry workers, childhood and recent exposures to SHS were related to respiratory symptoms.

Exposure to second-hand smoke damages everyday prospective memory

AIMS

Prospective memory (PM: remembering future intentions and activities) is critical to everyday remembering. This study compared a group of never-smokers who reported regular exposure to second-hand smoke (the SHS group) with a group of current smokers (the CS group) and a group of never-smokers who reported never having been exposed to SHS (the non-SHS group) on objective PM.

DESIGN

An existing groups design was employed to compare the SHS, CS and non-SHS groups.

PARTICIPANTS AND SETTING

Twenty-four SHS, 27 CS and 28 non-SHS were tested on objective PM. All participants were university undergraduates aged between 18-30 years. All participants were tested individually in a laboratory setting.

MEASUREMENTS

The Cambridge Prospective Memory Test (CAMPROMPT) was used to assess objective PM. Age, other drug use, mood and IQ were also measured as covariates in the study.

FINDINGS

The non-SHS group recalled significantly more time-based PM tasks than the SHS group (means = 16.3 versus 13.7, P < 0.001) and significantly more than the CS group (CS mean = 11.6, P < 0.001); and the SHS group recalled significantly more time-based tasks than the CS group (P < 0.002). The non-SHS group recalled significantly more event-based PM tasks than the CS group (means = 15.2 versus 11.3, P < 0.002) with no significant difference between the non-SHS group and SHS group (SHS mean = 14.3, P = 0.234); and the SHS group recalled significantly more event-based tasks than the CS group (P < 0.001).

CONCLUSION

Non-smokers exposed to second-hand smoke may suffer impairment in time-based prospective memory.

Indoor air pollution and respiratory health in the elderly

Data on respiratory effects of indoor air pollution in elderly are scanty. The purpose of this review is to summarize current knowledge on adverse respiratory effects of indoor air pollution in individuals aged over 65 years, by presenting existing epidemiological evidence. Using MEDLINE database through PubMed, we identified relevant publications published between 1991 and 2011 in English on respiratory health effects of indoor air pollution in elderly (>65 years). A total of 61 studies were found and after application of the inclusion criteria: (i) epidemiologic studies published in English in peer-reviewed journals between January 1991 and December 2011, (ii) study population with age over or equal 65 years, and (iii) outcome of respiratory symptoms and disease with the exclusion of lung cancer, 33 relevant publications were selected. Most of them showed significant relationships between exposure to major indoor air pollutants and various short-term and long-term respiratory health outcomes such as wheezing, breathlessness, cough, phlegm, asthma, COPD, lung cancer and more rarely lung function decline. The most consistent relationship is found between chronic obstructive pulmonary disease (COPD) and environmental tobacco smoke (ETS). Further studies in the elderly population are needed in order to define causal relationships between exposures to indoor air pollution and underlying mechanisms in this sub-population.

Everyday prospective memory and executive function deficits associated with exposure to second-hand smoke

This study explored whether exposure to second-hand smoke (SHS) has a detrimental impact upon everyday memory in two groups of non-smokers; one which reported regular exposure to SHS and one that reported never having been exposed to SHS. Thirty-four non-smokers who reported having been regularly exposed to SHS (SHS group) and 34 non-smokers who reported never having been exposed to SHS (non-SHS group) were compared on self-reports of prospective memory (PM: remembering future intentions and/or activities) and executive function (EF: those processes involved in attention, multitasking and decision-making). The Prospective and Retrospective Memory Questionnaire (PRMQ) assessed everyday PM lapses; the Executive Function Questionnaire (EFQ) assessed self-reported problems in EF; a drug-use questionnaire and a mood questionnaire were also administered. Two univariate ANCOVAs were applied to the PM and EF data, controlling for between-group differences in age, weekly alcohol use, anxiety and depression scores, and self-reported retrospective memory scores. The SHS group reported significantly more lapses on the PRMQ and more deficits on the EFQ than the non-SHS group. These findings provide new insights into PM and EF deficits associated with prolonged exposure to SHS in a group of non-smokers. Possible explanations and suggestions for future research are also considered.

A simulation study of finite-sample properties of marginal structural Cox proportional hazards models

Motivated by a previously published study of HIV treatment, we simulated data subject to time-varying confounding affected by prior treatment to examine some finite-sample properties of marginal structural Cox proportional hazards models. We compared (a) unadjusted, (b) regression-adjusted, (c) unstabilized, and (d) stabilized marginal structural (inverse probability-of-treatment [IPT] weighted) model estimators of effect in terms of bias, standard error, root mean squared error (MSE), and 95% confidence limit coverage over a range of research scenarios, including relatively small sample sizes and 10 study assessments. In the base-case scenario resembling the motivating example, where the true hazard ratio was 0.5, both IPT-weighted analyses were unbiased, whereas crude and adjusted analyses showed substantial bias towards and across the null. Stabilized IPT-weighted analyses remained unbiased across a range of scenarios, including relatively small sample size; however, the standard error was generally smaller in crude and adjusted models. In many cases, unstabilized weighted analysis showed a substantial increase in standard error compared with other approaches. Root MSE was smallest in the IPT-weighted analyses for the base-case scenario. In situations where time-varying confounding affected by prior treatment was absent, IPT-weighted analyses were less precise and therefore had greater root MSE compared with adjusted analyses. The 95% confidence limit coverage was close to nominal for all stabilized IPT-weighted but poor in crude, adjusted, and unstabilized IPT-weighted analysis. Under realistic scenarios, marginal structural Cox proportional hazards models performed according to expectations based on large-sample theory and provided accurate estimates of the hazard ratio.

Different genes interact with particulate matter and tobacco smoke exposure in affecting lung function decline in the general population

BACKGROUND

Oxidative stress related genes modify the effects of ambient air pollution or tobacco smoking on lung function decline. The impact of interactions might be substantial, but previous studies mostly focused on main effects of single genes.

OBJECTIVES

We studied the interaction of both exposures with a broad set of oxidative-stress related candidate genes and pathways on lung function decline and contrasted interactions between exposures.

METHODS

For 12679 single nucleotide polymorphisms (SNPs), change in forced expiratory volume in one second (FEV(1)), FEV(1) over forced vital capacity (FEV(1)/FVC), and mean forced expiratory flow between 25 and 75% of the FVC (FEF(25-75)) was regressed on interval exposure to particulate matter <10 µm in diameter (PM10) or packyears smoked (a), additive SNP effects (b), and interaction terms between (a) and (b) in 669 adults with GWAS data. Interaction p-values for 152 genes and 14 pathways were calculated by the adaptive rank truncation product (ARTP) method, and compared between exposures. Interaction effect sizes were contrasted for the strongest SNPs of nominally significant genes (p(interaction)<0.05). Replication was attempted for SNPs with MAF>10% in 3320 SAPALDIA participants without GWAS.

RESULTS

On the SNP-level, rs2035268 in gene SNCA accelerated FEV(1)/FVC decline by 3.8% (p(interaction) = 2.5×10(-6)), and rs12190800 in PARK2 attenuated FEV1 decline by 95.1 ml p(interaction) = 9.7×10(-8)) over 11 years, while interacting with PM10. Genes and pathways nominally interacting with PM10 and packyears exposure differed substantially. Gene CRISP2 presented a significant interaction with PM10 (p(interaction) = 3.0×10(-4)) on FEV(1)/FVC decline. Pathway interactions were weak. Replications for the strongest SNPs in PARK2 and CRISP2 were not successful.

CONCLUSIONS

Consistent with a stratified response to increasing oxidative stress, different genes and pathways potentially mediate PM10 and tobacco smoke effects on lung function decline. Ignoring environmental exposures would miss these patterns, but achieving sufficient sample size and comparability across study samples is challenging.

Reduced exercise tolerance and pulmonary capillary recruitment with remote secondhand smoke exposure

Rationale

Flight attendants who worked on commercial aircraft before the smoking ban in flights (pre-ban FAs) were exposed to high levels of secondhand smoke (SHS). We previously showed never-smoking pre-ban FAs to have reduced diffusing capacity (Dco) at rest.

Methods

To determine whether pre-ban FAs increase their Dco and pulmonary blood flow () during exercise, we administered a symptom-limited supine-posture progressively increasing cycle exercise test to determine the maximum work (watts) and oxygen uptake () achieved by FAs. After 30 min rest, we then measured Dco and at 20, 40, 60, and 80 percent of maximum observed work.

Results

The FAs with abnormal resting Dco achieved a lower level of maximum predicted work and compared to those with normal resting Dco (mean±SEM; 88.7±2.9 vs. 102.5±3.1%predicted ; p = 0.001). Exercise limitation was associated with the FAs' FEV₁ (r = 0.33; p = 0.003). The Dco increased less with exercise in those with abnormal resting Dco (mean±SEM: 1.36±0.16 vs. 1.90±0.16 ml/min/mmHg per 20% increase in predicted watts; p = 0.020), and amongst all FAs, the increase with exercise seemed to be incrementally lower in those with lower resting Dco. Exercise-induced increase in was not different in the two groups. However, the FAs with abnormal resting Dco had less augmentation of their Dco with increase in during exercise (mean±SEM: 0.93±0.06 vs. 1.47±0.09 ml/min/mmHg per L/min; p<0.0001). The Dco during exercise was inversely associated with years of exposure to SHS in those FAs with ≥10 years of pre-ban experience (r = −0.32; p = 0.032).

Conclusions

This cohort of never-smoking FAs with SHS exposure showed exercise limitation based on their resting Dco. Those with lower resting Dco had reduced pulmonary capillary recruitment. Exposure to SHS in the aircraft cabin seemed to be a predictor for lower Dco during exercise.

Role of CXCL5 in leukocyte recruitment to the lungs during secondhand smoke exposure

Chronic obstructive pulmonary disease (COPD) is the third leading cause of mortality in the United States. The major cause of COPD is cigarette smoking. Extensive leukocyte influx into the lungs, mediated by chemokines, is a critical event leading to COPD. Although both resident and myeloid cells secrete chemokines in response to inflammatory stimuli, little is known about the role of epithelial-derived chemokines, such as CXC chemokine ligand (CXCL)5, in the pathogenesis of cigarette smoke-induced inflammation. To explore the role of CXCL5, we generated CXCL5 gene-deficient mice and exposed them to secondhand smoke (SHS) for 5 hours/day for 5 days/week up to 3 weeks (subacute exposure). We observed a reduced recruitment of leukocytes to the lungs of CXCL5(-/-) mice compared with their wild-type (WT) counterparts, and noted that macrophages comprised the predominant leukocytes recruited to the lungs. Irradiation experiments performed on CXCL5(-/-) or WT mice transplanted with WT or CXCL5(-/-) bone marrow revealed that resident but not hematopoietic cell-driven CXCL5 is important for mediating SHS-induced lung inflammation. Interestingly, we observed a significant reduction of monocyte chemotactic protein-1 (MCP-1/CC chemokine ligand 2) concentrations in the lungs of CXCL5(-/-) mice. The instillation of recombinant MCP-1 in CXCL5(-/-) mice reversed macrophage recruitment. Our results also show the reduced activation of NF-κB/p65 in the lungs, as well as the attenuated activation of C-Jun N-terminal kinase, p42/44, and p38 mitogen-activated protein kinases and the expression of intercellular adhesion molecule-1 in the lungs of SHS-exposed CXCL5(-/-) mice. Our findings suggest an important role for CXCL5 in augmenting leukocyte recruitment in SHS-induced lung inflammation, and provide novel insights into CXCL5-driven pathogenesis.

Methods in tobacco abuse: proteomic changes following second-hand smoke exposure

Smoking is one of the leading preventable causes of disease, disability, and death in the USA and leads to more than 400,000 preventable deaths per year. Nicotine is the major alkaloid present in tobacco smoke, and many of the negative effects of smoking are attributed to nicotine. Nicotine is not only the addictive component of tobacco smoke, but also highly associated with carcinogenesis and induces oxidative stress. Furthermore, the administration of nicotine via subcutaneous mini-osmotic pumps or by injection is an established method in preclinical studies for this area of research. Thus, preclinical research on the negative effects of tobacco smoke and tobacco addiction has focused primarily on the effects of nicotine. However, there are over 4,500 components found in tobacco smoke, many of which are highly toxic. Other components may also contribute to the addictive properties of tobacco smoke. Furthermore, the negative effects of tobacco smoke are not isolated to the smoker but can have negative effects to those exposed to the secondhand smoke (SHS) stream. SHS exposure is the third leading cause of preventable death. Approximately 38,000 deaths per year are attributed to SHS exposure in the USA. SHS exposure increases the risk of heart disease by approximately 30% and is associated with increased risk of stroke, cancer, type II diabetes, as well as pulmonary disease. Thus, methods of administering tobacco smoke in a controlled environment will further our understanding of tobacco addiction and the role tobacco smoke in other disease states. Moreover, combining smoke exposure with proteomics can lead to the discovery of biomarkers that can be potentially useful tools in screening, early diagnosis, prevention, and treatment of diseases caused by SHS.

What are candidate biobehavioral mechanisms underlying the association between secondhand smoke exposure and mental health?

There is a consistent positive and significant association between secondhand smoke exposure and mental health outcomes in the literature. There are potential genetic and behavioral confounders (e.g., psychological stress, maternal depression, and family functioning) were discussed, as well as potential causal neurobiological pathways (e.g., dopamine system). Further neurobiological research to establish causal pathways is needed as well as the integration of positive observational findings into clinical and public health prevention practices.

Immediate and short-term consequences of secondhand smoke exposure on the respiratory system

PURPOSE OF REVIEW

This review critically evaluates the existing biological evidence regarding the immediate and short-term respiratory consequences of secondhand smoke (SHS).

RECENT FINDINGS

A 1-h exposure to SHS at bar/restaurant levels generates a marked inflammatory reaction and significant decrements on lung function. These deleterious effects of SHS are exacerbated when physical activity follows the SHS exposure, particularly in less fit individuals. The main respiratory effect mechanisms of SHS include a direct induction of growth factors resulting in airway remodelling and alterations in nitric oxide regulation. Pharmacological agents that increase either apical membrane chloride conductance or basolateral membrane potassium conductance may be of therapeutic benefit in patients with diseases related to SHS exposure. Moreover, treatment with statins has shown beneficial effects towards preventing the SHS-induced pulmonary hypertension, vascular remodelling, and endothelial dysfunction.

SUMMARY

Based on recently discovered evidence, even brief and short-term exposures to SHS generate significant adverse effects on the human respiratory system. Future research directions in this area include the concentrations of tobacco smoke constituents in the alveolar milieu following SHS exposure, individual susceptibility to SHS, as well as pharmacological treatments for reversing the SHS-induced airway remodelling.

A cross-validation deletion-substitution-addition model selection algorithm: Application to marginal structural models

The cross-validation deletion-substitution-addition (cvDSA) algorithm is based on data-adaptive estimation methodology to select and estimate marginal structural models (MSMs) for point treatment studies as well as models for conditional means where the outcome is continuous or binary. The algorithm builds and selects models based on user-defined criteria for model selection, and utilizes a loss function-based estimation procedure to distinguish between different model fits. In addition, the algorithm selects models based on cross-validation methodology to avoid "over-fitting" data. The cvDSA routine is an R software package available for download. An alternative R-package (DSA) based on the same principles as the cvDSA routine (i.e., cross-validation, loss function), but one that is faster and with additional refinements for selection and estimation of conditional means, is also available for download. Analyses of real and simulated data were conducted to demonstrate the use of these algorithms, and to compare MSMs where the causal effects were assumed (i.e., investigator-defined), with MSMs selected by the cvDSA. The package was used also to select models for the nuisance parameter (treatment) model to estimate the MSM parameters with inverse-probability of treatment weight (IPTW) estimation. Other estimation procedures (i.e., G-computation and double robust IPTW) are available also with the package.

Forced expiratory volume predicts all-cause and cancer mortality in Mumbai, India: results from a population-based cohort study

BACKGROUND

Reduction in pulmonary function, as estimated by forced expiratory volume in 1 s (FEV(1)), has been found to predict all-cause mortality in developed-country populations. This study was designed to examine the association between FEV(1) and mortality in an urban developing-country population.

METHODS

Data from the large, well-characterized Mumbai Cohort Study (Maharashtra, India) were used to compute hazard ratios (HRs; deaths/100-ml FEV(1)) and 95% confidence intervals (CIs) from Cox proportional hazards regression models in which age, tobacco use, education, height and relative body weight were controlled.

RESULTS

A total of 13,261 deaths occurred in this cohort of 148,173 individuals. After controlling for important covariates, there was a 1.7% reduction in risk of overall death in women for each 100-ml increment in FEV(1) (HR = 0.983; 95% CI = 0.980-0.986) and a 1.5% reduction in men (HR = 0.985; 95% CI = 0.984-0.986). There was a 1.6% reduction in cancer deaths in women (HR = 0.984; 95% CI = 0.973-0.996) and a 0.8% reduction in men (HR = 0.992; 95% CI = 0.987-0.997). The largest reductions in women were observed in tuberculosis deaths (3.7%/100-ml increment in FEV(1)), and in men in respiratory system deaths (3.2%).

CONCLUSIONS

In a densely populated urban Indian population, FEV(1) predicted overall and cancer mortality. Effects were larger in women and were not attenuated by exclusion of smokers or restricting analyses to subjects dying >2 years from recruitment. Because FEV(1) may be affected by air pollution, which is worsening in urban areas of most developing countries, further research is recommended to deepen understanding of these factors in relation to mortality.

Maternal smoking promotes chronic obstructive lung disease in the offspring as adults

INTRODUCTION

In utero and/or childhood environmental tobacco smoke exposure is well known to adversely affect lung function and to depreciate child's health in many ways. Fewer studies have assessed the long-term effects on COPD development and disease severity in later adulthood.

METHODS

COPD patients were interviewed using a structured questionnaire regarding their personal as well as the smoking habits of their parents. Data were compared with the disease history, e.g. COPD exacerbation rate, and their lung function data.

RESULTS

Between 2003 and 2004 COPD patients were recruited a) in a private practice specialized in pulmonary medicine (n = 133) and b) in a hospital (n = 158). 75% of their fathers and only 15.4 of all mothers smoked regularly. COPD patients from smoking mothers had lower FEV1 predicted than those raised in household without maternal smoking exposure: 39.4 +/- 9.5% vs. 51.9 +/- 6.0% (P = 0.037). Fathers had no effect on FEV1 regardless if they are smokers or non-smokers. Rate of severe exacerbations requiring hospitalization remained unaffected by parental second hand smoke exposure.

CONCLUSION

Maternal smoking negatively affects lung function of their offspring even in late adulthood when they develop COPD. It even aggravates the cumulative effect of active cigarette consumption. Clinical course of the COPD remained unaffected.