Optimal cutoff level of breath carbon monoxide for assessing smoking status in patients with asthma and COPD

Effectiveness of the spirometry-based motivational intervention to quit smoking: RESET randomised trial

BACKGROUND

The effectiveness of providing feedback on spirometry results for smoking cessation remains inconclusive according to the current evidence.

OBJECTIVES

To assess the effectiveness of a motivational intervention based on spirometry results in achieving prolonged smoking abstinence (12 months post-intervention).

DESIGN AND SETTING

A randomised, controlled, observer-blinded, multicentre clinical trial was conducted (from January 2012 to December 2015) in 20 primary healthcare centres in the Tarragona province, Spain.

METHODS

Participants, active smokers aged 35-70 without known respiratory disease, were recruited from primary healthcare centres by family doctors and nurses. They were randomly assigned to either the intervention group (IG = 308) or the control group (CG = 306). Both groups received brief smoking cessation counselling. Additionally, the IG underwent spirometry and received detailed information about the results, including lung age. The primary outcome was prolonged abstinence, defined as lasting at least 12 months and validated through cotinine measurement in urine.

RESULTS

The prolonged abstinence rate was 7.8% in the IG, compared to 2.6% in the CG (p = 0.004). At 12 months, in the multivariate analysis, the intervention was identified as an independent factor for smoking cessation (OR 2.8; 95%CI 1.2 to 7.7), a trend maintained throughout the follow-up (HR 2.74; 95%CI 1.13 to 6.62). Moreover, according to the Prochaska and DiClemente model, the preparation or action phase to quit was also associated with smoking cessation (HR 2.55, 95%CI 1.07 to 6.09).

CONCLUSION

A primary care-delivered intervention involving brief counselling and detailed spirometry information proves effective in increasing abstinence rates among active smokers without known respiratory disease. Additionally, smoking cessation is also influenced by the individual's stage of change.

TRIAL REGISTRATION

ClinicatTrials.gov NCT02153047.

Epigenetic biomarkers for smoking cessation

Cigarette smoking has been associated with epigenetic alterations that may be reversible upon cessation. As the most-studied epigenetic modification, DNA methylation is strongly associated with smoking exposure, providing a potential mechanism that links smoking to adverse health outcomes. Here, we reviewed the reversibility of DNA methylation in accessible peripheral tissues, mainly blood, in relation to cigarette smoking cessation and the utility of DNA methylation as a biomarker signature to differentiate current, former, and never smokers and to quantify time since cessation. We summarized thousands of differentially methylated Cytosine-Guanine (CpG) dinucleotides and regions associated with smoking cessation from candidate gene and epigenome-wide association studies, as well as the prediction accuracy of the multi-CpG predictors for smoking status. Overall, there is robust evidence for DNA methylation signature of cigarette smoking cessation. However, there are still gaps to fill, including (1) cell-type heterogeneity in measuring blood DNA methylation; (2) underrepresentation of non-European ancestry populations; (3) limited longitudinal data to quantitatively measure DNA methylation after smoking cessation over time; and (4) limited data to study the impact of smoking cessation on other epigenetic features, noncoding RNAs, and histone modifications. Epigenetic machinery provides promising biomarkers that can improve success in smoking cessation in the clinical setting. To achieve this goal, larger and more-diverse samples with longitudinal measures of a broader spectrum of epigenetic marks will be essential to developing a robust DNA methylation biomarker assay, followed by meeting validation requirements for the assay before being implemented as a clinically useful tool.

Effectiveness of a motivational intervention based on spirometry results to achieve smoking cessation in primary healthcare patients: randomised, parallel, controlled multicentre study

Objective

This 12-month study in a primary healthcare network aimed to assess the effectiveness of usual smoking cessation advice compared with personalised information about the spirometry results.

Design

Randomised, parallel, controlled, multicentre clinical trial.

Setting

This study involved 12 primary healthcare centres (Tarragona, Spain).

Participants

Active smokers aged 35–70 years, without known respiratory disease. Each participant received brief smoking cessation advice along with a spirometry assessment. Participants with normal results were randomised to the intervention group (IG), including detailed spirometry information at baseline and 6-month follow-up or control group (CG), which was simply informed that their spirometry values were within normal parameters.

Main outcome

Prolonged abstinence (12 months) validated by expired-CO testing.

Results

Spirometry was normal in 571 patients in 571 patients (45.9% male), 286 allocated to IG and 285 to CG. Baseline characteristics were comparable between the groups. Mean age was 49.8 (SD ±7.78) years and mean cumulative smoking exposure was 29.2 (±18.7) pack-years. Prolonged abstinence was 5.6% (16/286) in the IG, compared with 2.1% (6/285) in the CG (p=0.03); the cumulative abstinence curve was favourable in the IG (HR 1.98; 95% CI 1.29 to 3.04).

Conclusions

In active smokers without known respiratory disease, brief advice plus detailed spirometry information doubled prolonged abstinence rates, compared with brief advice alone, in 12-month follow-up, suggesting a more effective intervention to achieve smoking cessation in primary healthcare.

Trial registration number

NCT01194596.

Pilot feasibility trial of dual contingency management for cigarette smoking cessation and weight maintenance among weight-concerned female smokers

Many women who smoke cigarettes report that concern about weight gain is a barrier to quitting. Indeed, most quitters gain weight and some attribute relapses to weight gain concern. Contingency management (CM), which refers to reinforcing a target behavior with financial incentives, has been demonstrated effective for promoting smoking abstinence and weight management independently. We conducted a pilot trial to establish the feasibility of dual CM, in which both smoking cessation and weight maintenance were incentivized, as a smoking cessation intervention for female weight-concerned smokers. Participants (N = 10) received a 12-week intervention during which they earned financial incentives for smoking abstinence, verified by breath carbon monoxide (CO) testing, and for maintaining their weight (larger incentives for gaining less than five pounds, smaller incentives for 5-10 pound gain) while abstaining from smoking. They attended an end of intervention visit at week 13 and a follow-up visit at week 26. Total compensation was up to $550 ($255 for participation independent of smoking and weight, $145 for smoking abstinence incentives, and $150 for weight maintenance incentives). Results indicated that five of the 10 participants (50%) were continuously abstinent for at least 4 weeks and received at least 2 weight maintenance incentives. Three participants (33%) were abstinent at every visit they attended from quit date through week 26; 2 of these 3 had gained more than 10 pounds by week 26. Additional formative research to test alternative incentive schedules and modalities should be conducted before CM-W is evaluated in a larger trial. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Smoking status and second-hand smoke biomarkers in COPD, asthma and healthy controls

Introduction

Tobacco smoke worsens COPD and asthma. For healthy individuals, quantifying active and second-hand smoke (SHS) exposure clarifies the epidemiology of tobacco consumption and the efficacy of nonsmoking measures. Identifying tobacco exposure biomarkers and cut-offs might allow the creation of sensitive and specific tests.

Aim

We describe the state-of-the-art serum, urinary cotinine and exhaled carbon monoxide (CO) cut-offs for assessing smoking status and SHS exposure in adult patients with COPD or asthma, and healthy controls.

Methodology

After a keyword research in the PubMed database, we included papers reporting on the cut-offs of the investigated biomarkers in one of the populations of interest. Papers published before 2000, not in English, or reporting only data on nonadult subjects or on pregnant women were excluded from the analysis. 14 papers were included in the final analysis. We summarised diagnostic cut-offs for smoking status or SHS exposure in COPD, asthmatic and healthy control cohorts, reporting sensitivity and specificity when available.

Conclusion

Serum and urinary cotinine and exhaled CO are easy-to-standardise, affordable and objective tests for assessing smoking status and SHS exposure. Evidence on cut-offs with good sensitivity and specificity values is available mainly for healthy controls. For COPD and asthmatic patients, most of the currently available evidence focuses on exhaled CO, while studies on the use of cotinine with definite sensitivity and specificity values are still missing. Solid evidence on SHS exposure is available only for healthy controls. An integrated approach with a combination of these markers still needs evaluation.

Reliable cut-off values for smoking status in COPD and asthmatic adults are only available for exhaled COhttps://bit.ly/34lsHhD

Consistency and reliability of smoking-related variables: longitudinal study design in asthma and COPD

Introduction: Smoking has a significant impact on the development and progression of asthma and chronic obstructive pulmonary disease (COPD). Self-reported questionnaires and structured interviews are usually the only way to study patients' smoking history. In this study, we aim to examine the consistency of the responses of asthma and COPD patients to repeated standardised questions on their smoking habits over the period of 10 years. Methods: The study population consisted of 1329 asthma and 959 COPD patients, who enrolled in the study during years 2005-2007. A follow-up questionnaire was mailed to the participants 1, 2, 4, 6, 8, and 10 years after the recruitment. Results: Among the participants who returned three or more questionnaires (N = 1454), 78.5 % of the patients reported unchanged smoking status (never smoker, ex-smoker or current smoker) across the time. In 4.5% of the answers, the reported smoking statuses were considered unreliable/conflicting (first never smoker and, later, smoker or ex-smoker). The remainder of the patients changed their status from current smoker to ex-smoker and vice versa at least once, most likely due to struggling with quitting. COPD patients were more frequently heavy ex- or current smokers compared to the asthma group. The intraclass coefficient correlations between self-reported starting (0.85) and stopping (0.94) years as well as the consumption of cigarettes (0.74) over time showed good reliability among both asthma and COPD patients. Conclusion: Self-reported smoking data among elderly asthma and COPD patients over a 10-year follow-up is reliable. Pack years can be considered a rough estimate for their comprehensive consumption of tobacco products over time. We also observed that the questionnaire we used was not designed for dynamic changes in smoking which are rather common among heavy smokers especially when the follow-up time is several years, as in our study.

Preliminary exploration of secondhand smoke exposure in youth with Sickle Cell Disease: biochemical verification, pulmonary functioning, and health care utilization

Exposure to secondhand smoke (SHSe) can compound an already challenging set of health problems for youth with Sickle Cell Disease (SCD). Exposure to electronic cigarettes may also impact SCD symptomology and respiratory functioning. This study built on these previous findings by a) utilizing two objective measures of SHSe, salivary cotinine and exhaled carbon monoxide and b) examining the association of SHSe with emergency department utilization, physician-reported sickle cell crises, and pulmonary functioning. Caregivers (N = 31 dyads; Mage = 37.6 years; SD = 8.5 years) of youth with SCD (Mage = 9.0 years; SD = 4.5 years) completed self-report measures of tobacco/nicotine use. Youth provided a saliva sample to assess cotinine levels, and performed pulmonary function tests. Dyads provided breath samples for measurement of eCO. A chart review was conducted to obtain medical history and utilization. Majority of youth (88%) were exposed to SHS via salivary cotinine. Interestingly, no significant associations were observed between youth cotinine levels and emergency department utilization, physician-reported sickle cell crises, or pulmonary functioning. Present findings indicate a need to assess for SHSe using objective assessment measures. Future research should investigate which specific factors contribute to increase SHSe/SHVe in youth with SCD.

Indoor black carbon and biomarkers of systemic inflammation and endothelial activation in COPD patients

RATIONALE

Evidence linking traffic-related particle exposure to systemic effects in chronic obstructive lung disease (COPD) patients is limited.

OBJECTIVES

Assess relationships between indoor black carbon (BC), a tracer of traffic-related particles, and plasma biomarkers of systemic inflammation and endothelial activation.

METHODS

BC was measured by reflectance in fine particle samples over a mean of 7.6 days in homes of 85 COPD patients up to 4 times seasonally over a year. After the completion of sampling, plasma C-reactive protein (CRP), interleukin-6 (IL-6), and soluble vascular adhesion molecule-1 (sVCAM-1) were measured. Current smokers and homes with major sources of BC were excluded; therefore, indoor BC was primarily a measure of infiltrated outdoor BC. Mixed effects regression models with a random intercept for each participant were used to assess BC effects at different times (1-9 days before phlebotomy) and in the multi-day sample.

RESULTS

Measured median BC was 0.19 µg/m³ (interquartile range, IQR=0.22 µg/m³). Adjusting for season, race, age, BMI, heart disease, diabetes, ambient temperature, relative humidity, a recent cold or similar illness, and blood draw time, there was a positive relationship between BC and CRP. The largest effect size was for BC averaged over the previous seven days (11.8% increase in CRP per IQR; 95%CI = 1.8-22.9). Effects were greatest among non-statin users and persons with diabetes. There were positive effects of BC on IL-6 only in non-statin users. There were no associations with sVCAM-1.

CONCLUSIONS

These results demonstrate exposure-response relationships between indoor BC with biomarkers of systemic inflammation in COPD patients, with stronger relationships in persons not using statins and with diabetes.

The genetics of smoking in individuals with chronic obstructive pulmonary disease

Background

Smoking is the principal modifiable environmental risk factor for chronic obstructive pulmonary disease (COPD) which affects 300 million people and is the 3rd leading cause of death worldwide. Most of the genetic studies of smoking have relied on self-reported smoking status which is vulnerable to reporting and recall bias. Using data from the Lung Health Study (LHS), we sought to identify genetic variants associated with quantitative smoking and cessation in individuals with mild to moderate COPD.

Methods

The LHS is a longitudinal multicenter study of mild-to-moderate COPD subjects who were all smokers at recruitment. We performed genome-wide association studies (GWASs) for salivary cotinine (n = 4024), exhaled carbon monoxide (eCO) (n = 2854), cigarettes per day (CPD) (n = 2706) and smoking cessation at year 5 follow-up (n = 717 quitters and 2175 smokers). The GWAS analyses were adjusted for age, gender, and genetic principal components.

Results

For cotinine levels, SNPs near UGT2B10 gene achieved genome-wide significance (i.e. P < 5 × 10^− 8) with top SNP rs10023464, P = 1.27 × 10^− 11. For eCO levels, one significant SNP was identified which mapped to the CHRNA3 gene (rs12914385, P = 2.38 × 10^− 8). A borderline region mapping to KCNMA1 gene was associated with smoking cessation (rs207675, P = 5.95 × 10^− 8). Of the identified loci, only the CHRNA3/5 locus showed significant associations with lung function but only in heavy smokers. No regions met genome-wide significance for CPD.

Conclusion

The study demonstrates that using objective measures of smoking such as eCO and/or salivary cotinine can more precisely capture the genetic contribution to multiple aspects of smoking behaviour. The KCNMA1 gene association with smoking cessation may represent a potential therapeutic target and warrants further studies.

Trial registration

The Lung Health Study ClinicalTrials.gov Identifier: NCT00000568. Date of registration: October 28, 1999.

Electronic supplementary material

The online version of this article (10.1186/s12931-018-0762-7) contains supplementary material, which is available to authorized users.

Tissue Inhibitor of Metalloproteinases-1 as a Biological Marker in Colorectal Cancer: Influence of Smoking on Plasma Levels?

Background

At present plasma tissue inhibitor of metalloproteinases-1 (TIMP-1) is undergoing validation as a biological marker in colorectal cancer (CRC). The clinical implementation of plasma TIMP-1 in prognosis, prediction, screening and monitoring CRC requires robust information as to the influence of preanalytical factors, including inter- and intrapersonal biological variations. The aim of the present study was to evaluate the possible effects of smoking on the level of TIMP-1 in plasma from healthy subjects.

Materials and Methods

Forty-six never-smokers and 48 daily smokers participated in the 13-week study. Smokers were randomized into 3 groups of 16 subjects each: one group continued to smoke, a second group refrained from smoking and used a transdermal nicotine patch, and a third group refrained from smoking and used placebo patches. Plasma TIMP-1 levels were determined using ELISA.

Results

No significant differences in TIMP-1 levels could be shown between the smoking group, the 2 different abstinent smoking groups and the never-smoking group.

Conclusion

Smoking does not appear to have any influence on TIMP-1 levels in plasma collected from healthy subjects.

Smokers' Views on Personal Carbon Monoxide Monitors, Associated Apps, and Their Use: An Interview and Think-Aloud Study

Smartphone-based personal carbon monoxide (CO) monitors and associated apps, or "CO Smartphone Systems" (CSSs) for short, could enable smokers to independently monitor their smoking and quitting. This study explored views and preferences regarding CSSs and their use among 16 adult, UK-based smokers. First, semi-structured interviews explored participants' expectations of CSSs. Secondly, a think-aloud study identified participants' reactions to a personal CO monitor and to existing or prototype apps. Framework Analysis identified five themes: (1) General views, needs, and motivation to use CSSs; (2) Views on the personal CO monitor; (3) Practicalities of CSS use; (4) Desired features in associated apps; and (5) Factors affecting preferences for CSSs and their use. Participants had high expectations of CSSs and their potential to increase motivation. Priority app features included: easy CO testing journeys, relevant and motivating feedback, and recording of contextual data. Appearance and usability of the personal CO monitor, and accuracy and relevance of CO testing were considered important for engagement. Participants differed in their motivation to use and preferences for CSSs features and use, which might have non-trivial impact on evaluation efforts. Personal CO monitors and associated apps may be attractive tools for smokers, but making CSSs easy to use and evaluating these among different groups of smokers may be challenging.

Evaluation of nasal mucociliary clearance using saccharin test in smokers: A prospective study

BACKGROUND AND AIM

Nasal mucociliary clearance time (NMCT) can be measured with the saccharine clearance test which is an inexpensive and easy method. The aim of the present study was to compare and evaluate NMCT using the saccharine clearance test in smokers and non-smokers.

MATERIALS AND METHODS

Eighty-five patients whose ages ranged from 18 to 65 years were included in the study. Fifty of the patients were smokers (Group 1) while 35 were healthy, non-smoking volunteers (Group 2). Saccharin clearance test was used to evaluate NMCT in both groups. The results obtained were compared and the statistical analyses were performed using the Statistical Package for Social Sciences (SPSS).

RESULTS

NMCT was statistically significantly higher in Group 1 as compared to Group 2 (P < .001, Mann-Whitney U test). However, in cumulative smoking duration (pack-year), Fagerström test values and gender categories, there was no statistically significant difference in the average NMCT values of the two groups (P = .943 vs P = .812 respectively), P = .45).

CONCLUSION

Mucociliary activity, the primary defence mechanism of the respiratory epithelium, is significantly depressed in smokers. Our findings showed that the said depression is not associated with the number of cigarettes smoked, duration of smoking or nicotine dependence.

Use of Expired Air Carbon Monoxide Testing in Clinical Tobacco Treatment Settings

Carbon monoxide (CO) testing is considered an easy, noninvasive, and objective contribution to the assessment of smoking behavior, as CO is rapidly absorbed into the bloodstream when lit cigarettes or cigars are inhaled. CO testing is a medically important billable outpatient service that can contribute to sustainability of face to face tobacco use treatment services by clinicians. This article reviews research on the clinical use of CO testing to provide biomedical feedback in assessing smoking behavior, educating smokers on tobacco health effects, assisting with treatment planning, and as a motivational tool to encourage people to become tobacco free. Further research can focus on how to best incorporate CO testing into clinical practice, including more research on outcomes and methods to ensure that insurers reimburse for testing and improved ways to use CO testing to initiate attempts to quit tobacco use, to maintain cessation, and to prevent relapse.

Behavioral activation for smoking cessation and mood management following a cardiac event: results of a pilot randomized controlled trial

Background

Smoking cessation following hospitalization for Acute Coronary Syndrome (ACS) significantly reduces subsequent mortality. Depressed mood is a major barrier to cessation post-ACS. Although existing counseling treatments address smoking and depression independently in ACS patients, no integrated treatment addresses both. We developed an integrated treatment combining gold standard cessation counseling with behavioral activation-based mood management; Behavioral Activation Treatment for Cardiac Smokers (BAT-CS). The purpose of this pilot randomized controlled trial was to test feasibility, acceptability, and preliminary efficacy of BAT-CS vs. Standard of Care (SC).

Methods

Participants were recruited during hospitalization for ACS and were randomly assigned to BAT-CS or SC. The nicotine patch was offered in both conditions. Smoking, mood, and stress outcomes were collected at end-of-treatment and 24-week follow-up.

Results

Fifty-nine participants (28 BAT-CS, 31 SC) were recruited over 42 weeks, and assessment completion was above 80% in both conditions. Treatment acceptability and fidelity were high. At 24 week follow-up adjusted odds ratios favoring BAT-CS were 1.27 (95% CI: 0.41–3.93) for 7-day point prevalence abstinence and 1.27 (95% CI: 0.42–3.82) for continuous abstinence. Time to first smoking lapse was significantly longer in BAT-CS (62.4 vs. 31.8 days, p = 0.03). At 24-weeks, effect sizes for mood and stress outcomes ranged from η²_partial of.07–.11, with significant between treatment effects for positive affect, negative affect, and stress.

Conclusions

The design of this study proved feasible and acceptable. Results provide preliminary evidence that combining behavioral activation with standard smoking cessation counseling could be efficacious for this high risk population. A larger trial with longer follow-up is warranted.

Trial registration

NCT01964898. First received by clinicaltrials.gov October 15, 2013.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-017-4250-7) contains supplementary material, which is available to authorized users.

Kinetics of Exhaled Carbon Monoxide After Water-pipe Smoking Indoors and Outdoors

BACKGROUND

Despite accumulating evidence about its adverse health effects, water-pipe tobacco smoking has become very popular among youth. The aim of this study was to compare smoke exposure and the kinetics of exhaled carbon monoxide (eCO) between water-pipe and cigarette smokers under different conditions.

METHODS

Using a cross-over study design, changes in eCO and urinary cotinine levels were measured in a cohort of 32 healthy university students after sessions of water-pipe smoking indoors and outdoors. An indoor cigarette smoking session with equal amounts of tobacco was conducted for reference purposes. Both active and passive smokers participated in all sessions.

RESULTS

In indoor sessions, we found that among active participants, eCO levels were approximately 7.5-fold higher in water-pipe users than cigarette smokers. eCO levels remained significantly elevated even 10 h after discontinuing water-pipe smoking. Notably, eCO levels in passive water-pipe smokers were in the same range as in active cigarette smokers. Compared with indoor sessions, eCO levels in active water-pipe users were reduced in outdoor environments. Nonetheless, levels were still higher in these subjects than those in active cigarette smokers measured in indoor sessions. Urinary cotinine levels were comparable in active water-pipe and cigarette smokers.

CONCLUSIONS

Our results suggest that water-pipe smoking is associated with significantly higher toxicant exposure than cigarette smoking even in outdoor environments. Furthermore, even passive, indoor water-pipe smoke exposure may have significant health hazards compared with those of active cigarette smoking.

Internet-based self-tailored deposit contracts to promote smoking reduction and abstinence

Deposit contracting may reduce costs and increase efficacy in contingency management interventions. We evaluated two Internet-based deposit contract arrangements for smoking. In Experiment 1, nine participants deposited self-selected amounts that could be earned back for meeting goals. During treatment, participants were reimbursed for breath samples with less than or equal to 6 parts per million carbon monoxide and met the criterion for 47% of samples compared to 1% during baseline. In Experiment 2, 10 participants' deposits were matched up to $50. No samples met the criterion during baseline but 41.5% met it during treatment. The average deposit was $82 in Experiment 1 and $49 in Experiment 2. Participants rated the intervention favorably and sample submission rates were high. These experiments suggest that Internet-based self-tailored deposits are acceptable, feasible, and can promote brief reduction and abstinence in some smokers. Future research should investigate individual and intervention factors that affect long-term cessation and uptake of deposit contracts.

The Effect of Different Case Definitions of Current Smoking on the Discovery of Smoking-Related Blood Gene Expression Signatures in Chronic Obstructive Pulmonary Disease

INTRODUCTION

Smoking is the number one modifiable environmental risk factor for chronic obstructive pulmonary disease (COPD). Clinical, epidemiological and increasingly "omics" studies assess or adjust for current smoking status using only self-report, which may be inaccurate. Objective measures such as exhaled carbon monoxide (eCO) may also be problematic owing to limitations in the measurements and the relatively short half life of the molecule. In this study, we determined the impact of different case definitions of current cigarette smoking on gene expression in peripheral blood of patients with COPD.

METHODS

Peripheral blood gene expression from 573 former- and current-smokers with COPD in the ECLIPSE study was used to find genes whose expression was associated with smoking status. Current smoking was defined using self-report, eCO concentrations, or both. Linear regression was used to determine the association of current smoking status with gene expression adjusting for age, sex and propensity score. Pathway enrichment analyses were performed on genes with P < .001.

RESULT

Using self-report or eCO, only two genes were differentially expressed between current and ex-smokers, with no enrichment in biological processes. When current smoking was defined using both eCO and self-report, four genes were differentially expressed (LRRN3, PID1, FUCA1, GPR15) with enrichment in 40 biological pathways related to metabolic processes, response to hypoxia and hormonal stimulus. Additionally, the combined definition provided better distributions of test statistics for differential gene expression.

CONCLUSION

A combined phenotype of eCO and self report allows for better discovery of genes and pathways related to current smoking.

IMPLICATIONS

Studies relying only on self report of smoking status to assess or adjust for the impact of smoking may not fully capture its effect and will lead to residual confounding of results.

Reversion of AHRR Demethylation Is a Quantitative Biomarker of Smoking Cessation

Smoking is the largest preventable cause of morbidity and mortality in the world. Although there are effective pharmacologic and behavioral treatments for smoking cessation, our inability to objectively quantify smokers' progress in decreasing smoking has been a barrier to both clinical and research efforts. In prior work, we and others have shown that DNA methylation at cg05575921, a CpG residue in the aryl hydrocarbon receptor repressor (AHRR), can be used to determine smoking status and infer cigarette consumption history. In this study, we serially assessed self-report and existing objective markers of cigarette consumption in 35 subjects undergoing smoking cessation therapy, then quantified DNA methylation at cg05575921 at study entry and three subsequent time points. Five subjects who reported serum cotinine and exhaled carbon monoxide verified smoking abstinence for the 3 months prior to study exit averaged a 5.9% increase in DNA methylation at cg05575921 (p < 0.004) over the 6-month study. Although the other 30 subjects did not achieve smoking cessation at the 6-month time point, their self-reported reduction of cigarette consumption (mean = 6 cigarettes/day) was associated with a 2.8% increase DNA methylation at cg05575921 (p < 0.05). Finally, a survey of subjects as they exited the study demonstrated strong support for the clinical use of epigenetic biomarkers. We conclude that AHRR methylation status is a quantifiable biomarker for progress in smoking cessation that could have substantial impact on both smoking cessation treatment and research.

Comparison between objective measures of smoking and self-reported smoking status in patients with asthma or COPD: are our patients telling us the truth?

OBJECTIVE:

Smoking prevalence is frequently estimated on the basis of self-reported smoking status. That can lead to an underestimation of smoking rates. The aim of this study was to evaluate the difference between self-reported smoking status and that determined through the use of objective measures of smoking at a pulmonary outpatient clinic.

METHODS:

This was a cross-sectional study involving 144 individuals: 51 asthma patients, 53 COPD patients, 20 current smokers, and 20 never-smokers. Smoking status was determined on the basis of self-reports obtained in interviews, as well as through tests of exhaled carbon monoxide (eCO) and urinary cotinine.

RESULTS:

All of the asthma patients and COPD patients declared they were not current smokers. In the COPD and asthma patients, the median urinary cotinine concentration was 167 ng/mL (range, 2-5,348 ng/mL) and 47 ng/mL (range, 5-2,735 ng/mL), respectively (p < 0.0001), whereas the median eCO level was 8 ppm (range, 0-31 ppm) and 5 ppm (range, 2-45 ppm), respectively (p < 0.05). In 40 (38%) of the patients with asthma or COPD (n = 104), there was disagreement between the self-reported smoking status and that determined on the basis of the urinary cotinine concentration, a concentration > 200 ng/mL being considered indicative of current smoking. In 48 (46%) of those 104 patients, the self-reported non-smoking status was refuted by an eCO level > 6 ppm, which is also considered indicative of current smoking. In 30 (29%) of the patients with asthma or COPD, the urinary cotinine concentration and the eCO level both belied the patient claims of not being current smokers.

CONCLUSIONS:

Our findings suggest that high proportions of smoking pulmonary patients with lung disease falsely declare themselves to be nonsmokers. The accurate classification of smoking status is pivotal to the treatment of lung diseases. Objective measures of smoking could be helpful in improving clinical management and counseling.

The effect of Varenicline on smoking cessation in a group of young asthma patients

BACKGROUND

Tobacco use causes long-term morbidity and mortality. In patients with asthma, the frequency of smokers is high; however, asthmatic smokers experience more pronounced symptoms, accelerated loss of lung function and treatment resistance. Varenicline is an effective drug in smoking cessation, when investigated in COPD patients and general populations. The aim of the present study was to evaluate the effect of Varenicline on tobacco cessation in young asthmatics.

METHODS

In a randomized, placebo-controlled, double-blinded trial, 52 asthmatic current smokers (age 19-40) ≥ 10 cigarettes daily and ≥10 packyears (mean 15.6) were recruited to a 12 week treatment period with Varenicline or placebo (1:1) in parallel design. Evaluation of smoking status, asthma symptom score, general health quality score and methacholine challenge were performed at week 0, week 6, week 12 and week 24.

RESULTS

In the Varenicline group, at week 12, 69% of the patients quit smoking vs. 36% in the placebo group (p = 0.017, intended-to-treat analysis), but after 24 weeks, a high relapse rate was present (quit rates 19% vs. 16%, NS). After 6 weeks of treatment, significant improvements in airway hyperresponsiveness (AHR) in the Varenicline group was found (from 88% to 58%, p = 0.016), whereas no change was observed in the placebo group. Symptom score and general health quality improved in both the Varenicline and the placebo group.

CONCLUSION

We demonstrated that Varenicline can be used with a high probability of success with tobacco cessation in young smokers with asthma, but relapse rate after end of treatment is high. Quitting smoking can improve asthma control.

Tobacco Smoking Status as Assessed by Oral Questionnaire Results 30% Under-reporting by Adult Males in Rural India: A Confirmatory Comparison by Exhaled Breath Carbon Monoxide Analysis

Background:

The authenticity and true status of tobacco use, especially in the form of smoking among the patient clientele is always a matter of concern for their physicians.

Objectives:

The purpose of this study was to assess the authenticity of self-reported habit of tobacco smoking among a population sample of male respondents in rural India. Methods: Respondents were asked to complete oral questionnaires that assessed their status of tobacco smoking (if any) as well as duration of tobacco smoking, type of tobacco smoking, and frequency of tobacco smoking. Subsequently, exhaled breath carbon monoxide analysis was performed to detect their amounts of exhaled carbon monoxide.

Results:

In 175 respondents, the Smoke Check color indicators were significantly different (P < 0.0001) in the respondents who were diagnosed smokers per oral questionnaires (n = 92) versus diagnosed nonsmokers per oral questionnaires (n = 83). The probability statistics of authenticity of oral questionnaires for assessing smoking status showed that self-reporting was only 75% sensitive and 76% specific with 80% positive predictive value and 70% negative predictive value.

Conclusion:

True status of tobacco smoking with exhaled breath carbon monoxide analysis can be an easy clinical maneuver with community health screening and health promotion implications among patient populations in rural India.

The effect of azithromycin in adults with stable neutrophilic COPD: a double blind randomised, placebo controlled trial

Background

Chronic Obstructive Pulmonary Disease (COPD) is a progressive airway disease characterised by neutrophilic airway inflammation or bronchitis. Neutrophilic bronchitis is associated with both bacterial colonisation and lung function decline and is common in exacerbations of COPD. Despite current available therapies to control inflammation, neutrophilic bronchitis remains common. This study tested the hypothesis that azithromycin treatment, as an add-on to standard medication, would significantly reduce airway neutrophil and neutrophils chemokine (CXCL8) levels, as well as bacterial load. We conducted a randomised, double-blind, placebo-controlled study in COPD participants with stable neutrophilic bronchitis.

Methods

Eligible participants (n = 30) were randomised to azithromycin 250 mg daily or placebo for 12 weeks in addition to their standard respiratory medications. Sputum was induced at screening, randomisation and monthly for a 12 week treatment period and processed for differential cell counts, CXCL8 and neutrophil elastase assessment. Quantitative bacteriology was assessed in sputum samples at randomisation and the end of treatment visit. Severe exacerbations where symptoms increased requiring unscheduled treatment were recorded during the 12 week treatment period and for 14 weeks following treatment. A sub-group of participants underwent chest computed tomography scans (n = 15).

Results

Nine participants with neutrophilic bronchitis had a potentially pathogenic bacteria isolated and the median total bacterial load of all participants was 5.22×10⁷ cfu/mL. Azithromycin treatment resulted in a non-significant reduction in sputum neutrophil proportion, CXCL8 levels and bacterial load. The mean severe exacerbation rate was 0.33 per person per 26 weeks in the azithromycin group compared to 0.93 exacerbations per person in the placebo group (incidence rate ratio (95%CI): 0.37 (0.11,1.21), p = 0.062). For participants who underwent chest CT scans, no alterations were observed.

Conclusions

In stable COPD with neutrophilic bronchitis, add-on azithromycin therapy showed a trend to reduced severe exacerbations sputum neutrophils, CXCL8 levels and bacterial load. Future studies with a larger sample size are warranted.

Trial Registration

Australian New Zealand Clinical Trials Registry ACTRN12609000259246

A mobile-phone-based breath carbon monoxide meter to detect cigarette smoking

INTRODUCTION

Mobile phones hold considerable promise for delivering evidence-based smoking cessation interventions that require frequent and objective assessment of smoking status via breath carbon monoxide (Breath CO) measurement. However, there are currently no commercially available mobile-phone-based Breath CO meters. We developed a mobile-phone-based Breath CO meter prototype that attaches to and communicates with a smartphone through an audio port. We then evaluated the reliability and the validity of Breath CO measures collected with the mobile meter prototype and assessed the usability and acceptability of the meter.

METHODS

Participants included 20 regular smokers (≥10 cigarettes/day), 20 light smokers (<10 cigarettes/day), and 20 nonsmokers. Expired air samples were collected 4 times from each participant: twice with the mobile meter and twice with a commercially available Breath CO meter.

RESULTS

Measures calculated by the mobile meter correlated strongly with measures calculated by the commercial meter (r = .96, p < .001). Additionally, the mobile meter accurately distinguished between smokers and nonsmokers. The area under the receiver-operating characteristic curve for the mobile meter was 94.7%, and the meter had a combined sensitivity and specificity of 1.86 at an abstinence threshold of ≤6 ppm. Responses on an acceptability survey indicated that smokers liked the meter and would be interested in using it during a quit attempt.

CONCLUSIONS

The results of our study suggest that a mobile-phone-based Breath CO meter is a reliable, valid, and acceptable device for distinguishing between smokers and nonsmokers.

The ABCs of incentive-based treatment in health care: a behavior analytic framework to inform research and practice

Behavior plays an important role in health promotion. Exercise, smoking cessation, medication adherence, and other healthy behavior can help prevent, or even treat, some diseases. Consequently, interventions that promote healthy behavior have become increasingly common in health care settings. Many of these interventions award incentives contingent upon preventive health-related behavior. Incentive-based interventions vary considerably along several dimensions, including who is targeted in the intervention, which behavior is targeted, and what type of incentive is used. More research on the quantitative and qualitative features of many of these variables is still needed to inform treatment. However, extensive literature on basic and applied behavior analytic research is currently available to help guide the study and practice of incentive-based treatment in health care. In this integrated review, we discuss how behavior analytic research and theory can help treatment providers design and implement incentive-based interventions that promote healthy behavior.

Mucociliary clearance, airway inflammation and nasal symptoms in urban motorcyclists

OBJECTIVES

There is evidence that outdoor workers exposed to high levels of air pollution exhibit airway inflammation and increased airway symptoms. We hypothesized that these workers would experience increased airway symptoms and decreased nasal mucociliary clearance associated with their exposure to air pollution.

METHODS

In total, 25 non-smoking commercial motorcyclists, aged 18-44 years, were included in this study. These drivers work 8-12 hours per day, 5 days per week, driving on urban streets. Nasal mucociliary clearance was measured by the saccharine transit test; airway acidification was measured by assessing the pH of exhaled breath condensate; and airway symptoms were measured by the Sino-nasal Outcome Test-20 questionnaire. To assess personal air pollution exposure, the subjects used a passive-diffusion nitrogen dioxide (NO2) concentration-monitoring system during the 14 days before each assessment. The associations between NO2 and the airway outcomes were analyzed using the Mann-Whitney test and the Chi-Square test. Clinicaltrials.gov: NCT01976039.

RESULTS

Compared with clearance in healthy adult males, mucociliary clearance was decreased in 32% of the motorcyclists. Additionally, 64% of the motorcyclists had airway acidification and 92% experienced airway symptoms. The median personal NO2 exposure level was 75 mg/m3 for these subjects and a significant association was observed between NO2 and impaired mucociliary clearance (p=0.036).

CONCLUSION

Non-smoking commercial motorcyclists exhibit increased airway symptoms and airway acidification as well as decreased nasal mucociliary clearance, all of which are significantly associated with the amount of exposure to air pollution.

Longitudinal changes in clinical outcomes in older patients with asthma, COPD and asthma-COPD overlap syndrome

BACKGROUND

The progression of obstructive airway diseases (OADs) including asthma, chronic obstructive pulmonary disease (COPD) and asthma-COPD overlap syndrome in older adults is not well understood.

OBJECTIVE

To examine the prognosis of OADs and to identify potential determinants for longitudinal changes in clinical outcomes.

METHODS

We consecutively recruited 99 older adults (>55 years) with OADs who underwent a multidimensional assessment at baseline and 4 years which involved spirometry, 6-min walk distance (6MWD), assessments of health status (Saint George's Respiratory Questionnaire, SGRQ), comorbidity, and serum and sputum biomarkers. All-cause mortality and respiratory hospitalisation during the follow-up period were recorded. Clinical outcomes were compared between basal and final visits, and changes in clinical outcomes were compared among asthma, COPD and asthma-COPD overlap groups. Associations between clinical parameters, biomarkers and prognosis were examined.

RESULTS

After a median follow-up of 4.2 years, outcome data were available for 75 (75.8%) patients. There were 16 (16.2%) deaths. The BODE index predicted all-cause mortality in older people with OADs. While spirometry, 6MWD and SGRQ deteriorated significantly over the 4 years, there was significant heterogeneity in the longitudinal changes in these clinical outcomes. Participants with COPD had a significant decline in FEV1 (p = 0.003), SGRQ (p = 0.030) and 6MWD [decline of 75.5 (93.4) m, p = 0.024]. The change in 6MWD was lower in the asthma-COPD overlap group. Airflow reversibility was associated with a reduced decline in 6MWD.

CONCLUSION

COPD patients had a poor prognosis compared with asthma and asthma-COPD overlap patients. The BODE index is a useful prognostic indicator in older adults with OADs. Both airway disease diagnosis and BODE index warrant specific attention in clinical practice.

Influence of age, past smoking, and disease severity on TLR2, neutrophilic inflammation, and MMP-9 levels in COPD

Chronic obstructive pulmonary disease (COPD) is a common and serious respiratory disease, particularly in older individuals, characterised by fixed airway obstruction and persistent airway neutrophilia. The mechanisms that lead to these features are not well established. We investigated the contribution of age, prior smoking, and fixed airflow obstruction on sputum neutrophils, TLR2 expression, and markers of neutrophilic inflammation. Induced sputum from adults with COPD (n = 69) and healthy controls (n = 51) was examined. A sputum portion was dispersed, total, differential cell count and viability recorded, and supernatant assayed for CXCL8, matrix metalloproteinase- (MMP-) 9, neutrophil elastase, and soluble TLR2. Peripheral blood cells (n = 7) were stimulated and TLR2 activation examined. TLR2 levels were increased with ageing, while sputum neutrophils and total sputum MMP-9 levels increased with age, previous smoking, and COPD. In multivariate regression, TLR2 gene expression and MMP-9 levels were significant independent contributors to the proportion of sputum neutrophils after adjustment for age, prior smoking, and the presence of airflow obstruction. TLR2 stimulation led to enhanced release of MMP-9 from peripheral blood granulocytes. TLR2 stimulation activates neutrophils for MMP-9 release. Efforts to understand the mechanisms of TLR2 signalling and subsequent MMP-9 production in COPD may assist in understanding neutrophilic inflammation in COPD.

Carbon monoxide in exhaled breath testing and therapeutics

Carbon monoxide (CO), a low molecular weight gas, is a ubiquitous environmental product of organic combustion, which is also produced endogenously in the body, as the byproduct of heme metabolism. CO binds to hemoglobin, resulting in decreased oxygen delivery to bodily tissues at toxicological concentrations. At physiological concentrations, CO may have endogenous roles as a potential signaling mediator in vascular function and cellular homeostasis. Exhaled CO (eCO), similar to exhaled nitric oxide (eNO), has been evaluated as a candidate breath biomarker of pathophysiological states, including smoking status, and inflammatory diseases of the lung and other organs. eCO values have been evaluated as potential indicators of inflammation in asthma, stable COPD and exacerbations, cystic fibrosis, lung cancer, or during surgery or critical care. The utility of eCO as a marker of inflammation and its potential diagnostic value remain incompletely characterized. Among other candidate 'medicinal gases' with therapeutic potential, (e.g., NO and H2S), CO has been shown to act as an effective anti-inflammatory agent in preclinical animal models of inflammatory disease, acute lung injury, sepsis, ischemia/reperfusion injury and organ graft rejection. Current and future clinical trials will evaluate the clinical applicability of this gas as a biomarker and/or therapeutic in human disease.

Early impact of smoking on lung function, health, and well-being in adolescents

BACKGROUND

Smoking is the single most important risk factor for the development of chronic obstructive pulmonary disease, and more than 80% of adult smokers started smoking before the age of 20. The aim of our study was to evaluate the early impact of smoking on lung function, health, and well-being in adolescents.

METHODS

Twenty-four non-smokers (10 male, 14 female, mean age 17.6 years) and 24 smokers (mean of 3.5 pack-years; 15 male, 9 female, mean age 17.8 years) were compared in terms of lung function, bronchial hyperreactivity (BHR), levels of exhaled carbon monoxide (eCO), exhaled nitric oxide (eNO), and blood counts. A questionnaire containing items from the ISAAC study was used to detect differences in health and well-being.

RESULTS

There were no significant differences in lung function values between non-smokers and smokers (VC 95% vs. 103%, FEV(1) 106% vs. 116%, FEV(1) %/VC MAX 94.6% vs. 95.2%), whereas BHR significantly differed (P < 0.05). Furthermore, significant differences were found for eCO, eNO, Hb, leukocytes, and neutrophils. Health and well-being in terms of sleep and physical activity were significantly worse in smokers.

CONCLUSION

Our results suggest an early impact of smoking on health after as few as 3.5 pack-years. Early signs of smoking are an increase in BHR, changes in blood count and a decrease of eNO even before changes in lung function become apparent.

A Retrospective Comparison of Varenicline Monotherapy Versus the Combination of Varenicline and Bupropion or Bupropion and Nicotine Patches in a VA Tobacco Cessation Clinic

Purpose:To determine whether the combination of bupropion SR and varenicline offers improved smoking cessation outcomes compared to varenicline monotherapy or to combination of bupro-pion SR and nicotine patch.Methods:This retrospective chart review included 489 volunteer enrolees in a Veterans Affairs (VA) tobacco cessation clinic who received one of the three treatments upon clinic enrolment. The study endpoints were smoking cessation and clinic completion rates, changes in the number of cigarettes smoked, carbon monoxide (CO) levels, urges to smoke, self-confidence to quit and medication-attributed adverse effects.Results:The relative smoking cessation rates were 33%, 32%, and 40% for bupropion SR and nicotine patch, bupropion SR and varenicline, and varenicline groups, respectively. The 0.21 p value established that no significant cessation rate differences existed between any of the groups. Varenicline alone or in combination was as well tolerated as the combination of bupropion SR and nicotine patch.Conclusions:The combination of bupropion SR and varenicline did not demonstrate any smoking cessation advantage over varenicline monotherapy or the combination of bupropion SR and nicotine patch and therefore do not support the use of bupro-pion SR and varenicline over varenicline monotherapy.

Assessing recent smoking status by measuring exhaled carbon monoxide levels

BACKGROUND

Cigarette smoke causes both acute and chronic changes of the immune system. Excluding recent smoking is therefore important in clinical studies with chronic inflammation as primary focus. In this context, it is common to ask the study subjects to refrain from smoking within a certain time frame prior to sampling. The duration of the smoking cessation is typically from midnight the evening before, i.e. 8 hours from sampling. As it has been shown that a proportion of current smokers underestimates or denies smoking, objective assessment of recent smoking status is of great importance. Our aim was to extend the use of exhaled carbon monoxide (CO(breath)), a well-established method for separating smokers from non-smokers, to assessment of recent smoking status.

METHODS AND FINDINGS

The time course of CO(breath) decline was investigated by hourly measurements during one day on non-symptomatic smokers and non-smokers (6+7), as well as by measurements on three separate occasions on non-smokers (n = 29), smokers with normal lung function (n = 38) and smokers with chronic obstructive pulmonary disease (n = 19) participating in a clinical study. We used regression analysis to model the decay, and receiver operator characteristics analysis for evaluation of model performance. The decline was described as a mono-exponential decay (r(2) = 0.7) with a half-life of 4.5 hours. CO decline rate depends on initial CO levels, and by necessity a generic cut-off is therefore crude as initial CO(breath) varies a lot between individuals. However, a cut-off level of 12 ppm could classify recent smokers from smokers having refrained from smoking during the past 8 hours with a specificity of 94% and a sensitivity of 90%.

CONCLUSIONS

We hereby describe a method for classifying recent smokers from smokers having refrained from smoking for >8 hours that is easy to implement in a clinical setting.

Effectiveness of a structured motivational intervention including smoking cessation advice and spirometry information in the primary care setting: the ESPITAP study

Background

There is current controversy about the efficacy of smoking cessation interventions that are based on information obtained by spirometry. The objective of this study is to evaluate the effectiveness in the primary care setting of structured motivational intervention to achieve smoking cessation, compared with usual clinical practice.

Methods

Discussion

Application of a motivational intervention based on structured information about spirometry results, improved abstinence rates among smokers seen in actual clinical practice conditions in primary care.

Trial registration

ClinicalTrial.gov, number NCT01194596.

Evaluation of the exhaled carbon monoxide levels in smokers with COPD

OBJECTIVE

To measure exhaled carbon monoxide (COex) levels in smokers with and without COPD.

METHODS

Smokers treated at outpatient clinics of São Lucas Hospital in the city of Porto Alegre, Brazil, between September of 2007 and March of 2009 were invited to participate in this study. The participants completed a questionnaire regarding demographic and epidemiologic characteristics and were submitted to spirometry, as well as to determination of COex and urinary cotinine levels. The participants were divided into two groups: those with COPD and those without COPD.

RESULTS

The study involved 294 smokers, of whom 174 (59.18%) had been diagnosed with COPD. All of the participants presented with urinary cotinine levels > 50 ng/mL. Smokers with COPD presented significantly higher median values for age and pack-years than did those without COPD (p < 0.001 and p = 0.026, respectively). No other statistically significant differences were found. When adjusted for gender, age at smoking onset, number of cigarettes/day and urinary cotinine level, the mean values of COex were higher, but not statistically so, in the COPD group than in the non-COPD group (17.8 +/- 0.6 ppm and 16.6 +/- 0.7 ppm, respectively; p = 0.200). The differences remained nonsignificant when plotted logarithmically. A wide dispersion of COex values was found when the participants were classified by FEV1 level (r = -0.06; p = 0.53) or by Global Initiative for Chronic Obstructive Lung Disease classification (r = 0.08; p = 0.34). The proportions of false-negative results for smoking were 18.4% and 6.7%, respectively, in the COPD and non-COPD groups (p = 0.007).

CONCLUSIONS

Since COex values did not differ significantly between smokers with COPD and those without, there seem to be no major contraindications to their use in smokers with COPD.

Exhaled carbon monoxide in airway diseases: from research findings to clinical relevance

Breath tests have gained increasing interest in recent years mainly driven by the unmet clinical need to monitor airway diseases and to obtain information of unravelled aspects of respiratory disorders. Carbon monoxide is present in the exhaled breath and has been suggested to reflect ongoing oxidative stress, even if there are some confounding factors limiting its clinical usefulness. Increased concentration of exhaled carbon monoxide has been demonstrated in different acute and chronic airway diseases including allergic rhinitis, asthma, bronchiectasis, and post transplant bronchiolitis obliterans syndrome. Although exhaled carbon monoxide might not prove as a clinically useful biomarker of airway diseases, its measurement has helped to understand the place of heme oxygenase activity in allergic and non-allergic airway diseases. The scope of this review is the exciting field of exhaled carbon monoxide in airway diseases.

Exhaled carbon monoxide and risk of metabolic syndrome and cardiovascular disease in the community

BACKGROUND

Endogenous carbon monoxide (CO) at physiological concentrations is cytoprotective, whereas excess levels reflect underlying oxidative stress, inflammation, and vascular pathology and portend adverse clinical sequelae. However, the relation of exhaled CO to metabolic/vascular risk in the community is unknown.

METHODS AND RESULTS

We related exhaled CO, a surrogate measure of blood CO concentration, to the risk of developing new-onset metabolic syndrome and incident cardiovascular disease following 14 943 routine examinations (4139 unique participants; mean age, 46 years, 53% women) in the Framingham Heart Study. Baseline exhaled CO was associated with the presence of cardiometabolic risk factors (including smoking) and prevalent metabolic syndrome (odds ratio, 1.09 per log CO; 95% confidence interval, 1.02 to 1.17; P=0.01). During up to 4 years of follow-up, 1458 participants developed new-onset metabolic syndrome, and 416 experienced a first cardiovascular disease event. Compared with individuals in the lowest quartile of exhaled CO, those in the highest quartile were more likely to develop metabolic syndrome (odds ratio, 1.48; 95% confidence interval, 1.25 to 1.76; P<0.0001) and cardiovascular disease events (hazard ratio, 1.66; 95% confidence interval, 1.14 to 2.40; P=0.008) in multivariable analyses that included adjustment for smoking status.

CONCLUSION

In our community-based sample, higher exhaled CO levels predicted the development of metabolic syndrome and future cardiovascular disease events, underscoring the importance of this endogenous second messenger in the pathogenesis of metabolic and vascular risk.

Exhaled carbon monoxide in asthmatics: a meta-analysis

Background

The non-invasive assessment of airway inflammation is potentially advantageous in asthma management. Exhaled carbon monoxide (eCO) measurement is cheap and has been proposed to reflect airway inflammation and oxidative stress but current data are conflicting. The purpose of this meta-analysis is to determine whether eCO is elevated in asthmatics, is regulated by steroid treatment and reflects disease severity and control.

Methods

A systematic search for English language articles published between 1997 and 2009 was performed using Medline, Embase and Cochrane databases. Observational studies comparing eCO in non-smoking asthmatics and healthy subjects or asthmatics before and after steroid treatment were included. Data were independently extracted by two investigators and analyzed to generate weighted mean differences using either a fixed or random effects meta-analysis depending upon the degree of heterogeneity.

Results

18 studies were included in the meta-analysis. The eCO level was significantly higher in asthmatics as compared to healthy subjects and in intermittent asthma as compared to persistent asthma. However, eCO could not distinguish between steroid-treated asthmatics and steroid-free patients nor separate controlled and partly-controlled asthma from uncontrolled asthma in cross-sectional studies. In contrast, eCO was significantly reduced following a course of corticosteroid treatment.

Conclusions

eCO is elevated in asthmatics but levels only partially reflect disease severity and control. eCO might be a potentially useful non-invasive biomarker of airway inflammation and oxidative stress in nonsmoking asthmatics.

Smoking attenuates wound inflammation and proliferation while smoking cessation restores inflammation but not proliferation

Full-thickness 5 mm punch biopsy wounds were made lateral to the sacrum in 48 smokers and 30 never smokers. After 1 week, the wounds were excised and fixed. The smokers were then randomized to continuous smoking or abstinence with a transdermal nicotine patch or a placebo patch. The sequence of wounding and excision was repeated after 4, 8, and 12 weeks. All excised tissue was stained with hematoxylin-eosin and immunohistochemically for macrophages (CD68), procollagen 1 N-terminal propeptide (PINP) in fibroblasts, and endothelial cells (CD31). The cellularity was assessed and scored by two independent histopathologists, and for the analysis, proportional odds models and random effect models for repeated measurements were applied. Macrophages and PINP-stained fibroblasts were reduced in the smokers' wounds (0.28 [0.14-0.58] [OR, 95%CI]; p=0.01 and 0.37[0.19-0.70]; p<0.01, respectively, when compared with never smokers' wounds). Inflammation scores were marginally affected. Following smoking cessation, inflammatory cell infiltration and macrophages in the wounds increased. PINP-stained fibroblasts were unaffected. Neovascularization was not affected by smoking or abstinence. Wound inflammation and fibroblast proliferation were attenuated in smokers, suggesting delayed healing. Abstinence from smoking restores inflammation, but does not affect proliferation. These findings suggest a pathophysiologic mechanism for postoperative wound infection and dehiscence in smokers and why smoking cessation appears to reduce wound infection but not dehiscence.

[Interpretation of exhaled CO levels in studies on smoking]

INTRODUCTION

Exhaled carbon monoxide (ECO) concentration provides an easy, fast and non invasive means of assessing smoking status. However, some difficulties have to be considered when interpreting ECO levels.

BACKGROUND

CO is a non-specific biomarker of tobacco exposure. Its half-life is short (2-6 hours). CO reflects the intensity of tobacco smoke inhalation. Its high affinity for haemoglobin, producing carboxyhaemoglobin (COHb), leads to tissue hypoxia. The correlation between ECO and COHb is strong and linear. Gender, pulmonary ventilation, physical exercise and time of day may induce variations in CO elimination. ECO levels are increased in the following situations: consumption of alcohol or polyol-rich sweets, lactose intolerance, haemolytic anaemia, types 1 and 2 diabetes, asthma, chronic obstructive pulmonary disease (COPD) and bronchiectasis. Airflow obstruction alters the correlation between ECO and blood COHb. Smokers and nonsmokers can be differentiated by threshold levels of ECO in the range three to ten parts per million (ppm). For patients suffering from asthma and COPD, however, the threshold levels of ECO are 10 and 11 ppm respectively.

CONCLUSION

Both false positive results and clinical disorders associated with higher production of endogenous CO have to be taken into account when blood COHb and/or ECO levels are interpreted in clinical practice.

[Tobacco smoking treatment strategy in COPD]

Smoking cessation is one of the most important ways of improving the prognosis of COPD patients. Based on currently available evidence professional health workers should take a proactive and continuous role with smokers, motivating them to stop smoking and providing treatment to aid smoking cessation. The treatment should include pharmacotherapy in addition to behavioural support and should be part of management of the patient's chronic respiratory condition, as the COPD National Prevention and Treatment Programme recommends. Respiratory physicians and other professional health workers should receive training to ensure they have the necessary knowledge, attitude and skills to undertake these initiatives or to refer the smokers to a suitable qualified specialist. In the near future specialised smoking units should provide specific support, promote training, improve research and awareness and establish tobacco control measures in hospitals and primary health care centres.

The RealU online cessation intervention for college smokers: a randomized controlled trial

OBJECTIVES

To determine the efficacy of providing online cessation intervention for college smokers.

METHODS

This is a two-group randomized controlled trial. The intervention group received $10 weekly incentives to visit an online college life magazine that provided personalized smoking cessation messages and peer email support. Evaluation assessments occurred at baseline and 8, 20, and 30 weeks after enrollment. The primary outcome is self-reported 30-day abstinence at week 30. Carbon monoxide (CO) breath testing was performed for participants reporting 30-day abstinence at week 30.

RESULTS

Five-hundred and seventeen college smokers at the University of Minnesota were enrolled via internet health screening (control=260, intervention=257) in the fall of 2004. Intervention participants completed an average of 18.9 (SD 2.5) of 20 weekly website visits over the course of the study. The rate of 30-day abstinence at week 30 was higher for the intervention compared to the control group (41% vs. 23%, p<0.001). CO testing showed low rates of under-reporting. There was no difference in self-reported 6-month prolonged abstinence measured at week 30.

CONCLUSION

Providing personalized smoking cessation messages as part of a general interest online college life magazine increased 30-day abstinence by the end of this two semester intervention.

[In-patient smoker? - Providing appropriate intervention]

Tobacco use is the most avoidable cause of death. Other than provoking multiple diseases requiring hospitalisation, Tobacco Use is also a disease requiring management in the hospital setting, not only in terms of controlling the withdrawal symptoms of the patient, who has been abruptly prohibited from smoking, but also for fulfilling legislation which prohibits tobacco use in the health services, the only efficient way of preventing exposure of non-smokers to environmental tobacco smoke. Treating the in-patient smoker in an appropriate way also provides a window of opportunity for promoting not just a temporary but a complete smoking cessation.

Exhaled carbon monoxide as a biomarker of inflammatory lung disease

Carbon monoxide (CO) can be detected on the exhaled breath of humans. Exhaled CO (E-CO) originates from the inspiration of ambient CO and from endogenous metabolic sources that include heme metabolism catalyzed by heme oxygenase (HO) enzymes. HO occurs in both constitutive (HO-2) and inducible (HO-1) forms; the latter responds to pro-inflammatory or pro-oxidative stimuli. E-CO may arise in the airways from inducible HO-1 activity in the bronchial epithelium, alveolar macrophages and other lung cell types, as a consequence of local inflammation, and from the alveolae in equilibrium with carboxyhemoglobin (Hb-CO) in the pulmonary circulation. Elevations in Hb-CO in turn may reflect increases in ambient CO, as well as increased HO activity in systemic tissues. E-CO increases dramatically in active smokers and can be used to monitor the smoking habit. Elevations in E-CO have been observed in critically ill or post-surgical patients and those with various pulmonary diseases associated with inflammation, including chronic obstructive pulmonary disease (COPD), asthma, cystic fibrosis and infections. Despite improvements in the standardization and sensitivity of methods to detect E-CO, the predictive value of this measurement as a diagnostic tool remains unclear.

Validity of Expired Carbon Monoxide and Urine Cotinine Using Dipstick Method to Assess Smoking Status

OBJECTIVES

We investigated the validity of the dipstick method (Mossman Associates Inc. USA) and the expired CO method to distinguish between smokers and nonsmokers. We also elucidated the related factors of the two methods.

METHODS

This study included 244 smokers and 50 ex-smokers, recruited from smoking cessation clinics at 4 local public health centers, who had quit for over 4 weeks. We calculated the sensitivity, specificity and Kappa coefficient of each method for validity. We obtained ROC curve, predictive value and agreement to determine the cutoff of expired air CO method. Finally, we elucidated the related factors and compared their effect powers using the standardized regression coefficient.

RESULTS

The dipstick method showed a sensitivity of 92.6%, specificity of 96.0% and Kappa coefficient of 0.79. The best cutoff value to distinguish smokers was 5-6 ppm. At 5 ppm, the expired CO method showed a sensitivity of 94.3%, specificity of 82.0% and Kappa coefficient of 0.73. And at 6 ppm, sensitivity, specificity and Kappa coefficient were 88.5%, 86.0% and 0.64, respectively. Therefore, the dipstick method had higher sensitivity and specificity than the expired CO method. The dipstick and expired CO methods were significantly increased with increasing smoking amount. With longer time since the last smoking, expired CO showed a rapid decrease after 4 hours, whereas the dipstick method showed relatively stable levels for more than 4 hours.

CONCLUSIONS

The dipstick and expired CO methods were both good indicators for assessing smoking status. However, the former showed higher sensitivity and specificity and stable levels over longer hours after smoking, compared to the expired CO method.

Transdermal nicotine patch enhances type I collagen synthesis in abstinent smokers

Cigarette smokers deposit less collagen, expressed as hydroxyproline, in granulation tissue than nonsmokers. We studied the effect of abstinence from smoking and transdermal nicotine patches on deposition of hydroxyproline, proline, type I procollagen, and total proteins. Fifty-four healthy smokers were studied during 10 days of smoking and again from days 10 to 20 following smoking cessation. After the first 10 days of abstinence they were randomized to double-blind treatment with transdermal nicotine patches of 25 mg/day or placebo for a period of 10 days. During this period and during smoking, an expanded polytetrafluoroethylene tube was implanted into the subcutis. Following removal of the implant, total amino acids and peptides were extracted. Hydroxyproline and proline were analyzed by high-pressure liquid chromatography, type I procollagen was analyzed by enzyme-linked immunoassay, and total proteins were determined colorimetrically. In the 39 subjects who complied with the study protocol, abstinence from smoking did not affect the deposition of hydroxyproline, proline, type I procollagen, or total protein in the implants. During abstinence, the type I procollagen level increased by 18% in the transdermal nicotine patches group and decreased by 10% in the placebo group (p<0.05). We conclude that 20 days of abstinence from smoking does not affect collagen deposition in granulation tissue. However, in abstinent smokers, transdermal nicotine patches appears to increase type I collagen synthesis.