The Accuracy of a Lower-Cost Breath Carbon Monoxide Meter in Distinguishing Smokers from Non-smokers

Evaluation of the relationship between the level of addiction and exhaled carbon monoxide levels with neutrophil-to-lymphocyte and platelet-to-lymphocyte ratios in smokers

INTRODUCTION

Smoking has been reported to increase systemic inflammation. The neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) are used as markers for systemic inflammation. In this study, the primary aim was to determine the NLR and PLR ratios in smokers. Secondly, we aimed to evaluate the relationship between the level of addiction and carbon monoxide (CO) level in the expiratory air, with these ratios.

METHODS

This study was designed as a single-center, cross-sectional study. It was conducted with chronic smokers aged 18–40 years, without known health problems, visiting the smoking cessation outpatient clinic of a tertiary hospital. Sociodemographic data and smoking characteristics were collected, and exhaled CO levels were measured. Complete blood count (CBC) results were recorded, including NLR and PLR.

RESULTS

The mean age of 247 patients was 31.2±6.1 years, with the majority of patients (68.4%) being male. While the mean value of CO was 11.6±5.6 ppm, 42.1% of cases had a high level of addiction. A statistically significant relationship was found between NLR and addiction levels, the CO level, and the amount of smoking in cigarettes/day and packs/year (all p=0.000). A statistically significant relationship was also found between PLR and addiction levels, CO level, cigarettes/day and packs/year (p=0.000, p=0.03, p=0.000, p=0.003, respectively).

CONCLUSIONS

We found that as the level of addiction, cigarette use, and exhaled CO levels increased in smokers, NLR and PLR increased. Our data revealed that NLR and PLR may be a simple and easily assessable proxy of systemic inflammation in smokers.

Effectiveness of a Dyadic Buddy App for Smoking Cessation: Randomized Controlled Trial

BACKGROUND

Tobacco smoking is one of the biggest public health threats. Smartphone apps offer new promising opportunities for supporting smoking cessation in real time. This randomized controlled trial investigated the effectiveness of an app that encourages individuals to quit smoking with the help of a social network member (buddy) in daily life.

OBJECTIVE

The objective of this study is to test the effectiveness of the SmokeFree buddy app compared with a control group with self-reported smoking abstinence and carbon monoxide (CO)-verified smoking abstinence as primary outcomes and self-reports of smoked cigarettes per day (CPD) as a secondary outcome.

METHODS

A total of 162 adults who smoked participated in this single-blind, two-arm, parallel-group, intensive longitudinal randomized controlled trial. Around a self-set quit date (ie, 7 days before the self-set quit date and 20 days after) and 6 months later, participants of the intervention and control groups reported on daily smoking abstinence and CPD in end-of-day diaries. Daily smoking abstinence was verified via daily exhaled CO assessments. This assessment was administered via an app displaying results of exhaled CO, thus addressing self-monitoring in both groups. In addition, participants in the intervention group used the SmokeFree buddy app, a multicomponent app that facilitates social support from a buddy of choice.

RESULTS

A significant reduction in CPD from baseline to the 6-month follow-up was observed among participants in both groups. Multilevel analyses revealed no significant intervention effect on self-reported and CO-verified daily smoking abstinence at the quit date and 3 weeks later. However, CPD was lower at the quit date and 3 weeks later in the intervention group than in the control group. No significant differences between groups were found for any outcome measures 6 months after the quit date. Overall, low app engagement and low perceived usefulness were observed.

CONCLUSIONS

Despite some encouraging short-term findings on the amount of smoking, the SmokeFree buddy app did not have beneficial effects on smoking abstinence over and above the self-monitoring control condition. Future studies should examine whether and what support processes can be effectively stimulated and how app use can be improved to better achieve this goal.

TRIAL REGISTRATION

ISRCTN Registry 11154315; https://www.isrctn.com/ISRCTN11154315.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

RR2-10.1186/s12889-019-7723-z.

Evaluation of the relationship between the level of addiction and exhaled carbon monoxide levels with QT dispersion in smokers

INTRODUCTION

Smoking increases the risk of arrhythmia. QT dispersion (QTd) is an important indicator for the determination of ventricular arrhythmia. In this study, we aimed to determine the arrhythmia risk by evaluating QTd in smokers and to assess the relationship between the level of nicotine addiction and carbon monoxide (CO) level in the expiratory air.

METHODS

This study was designed as a single-center, cross-sectional study. Among the chronic smokers referred to the Smoking Cessation Clinic of a tertiary hospital between October 2019 and January 2020, all those who had no risk factors for cardiac arrhythmias, except smoking, were included in the study. Sociodemographic data and smoking characteristics of the participants were collected and exhaled CO levels were measured. QT intervals were measured in all leads by using a 12-lead standard electrocardiogram (ECG), and heart rate corrected QT (QTc) intervals, QT dispersion (QTd), and corrected QT dispersion (QTcd) were calculated.

RESULTS

The mean age of the 250 patients was 37.2±9.3 years and the majority of patients (65%) were male. The mean amount of smoking was 25.74±16.03 packs/year and the mean value of CO was 12.36±7.06 ppm. The mean QTd was 23.83±13.12 ms, and the mean QTcd was 26.63±15.02 ms. A statistically significant relationship was found between QTd and QTcd and level of addiction, consumption of sticks/day and packs/year, and exhaled CO values (all p<0.001).

CONCLUSIONS

It was found that as the level of addiction, cigarette use amount, exhaled CO levels, and BMI increased in smokers, QT dispersion and arrhythmia risk increased.

Mobile, Remote, and Individual Focused: Comparing Breath Carbon Monoxide Readings and Abstinence Between Smartphone-Enabled and Stand-Alone Monitors

INTRODUCTION

Newly available, smartphone-enabled carbon monoxide (CO) monitors are lower in cost than traditional stand-alone monitors and represent a marked advancement for smoking research. New products are promising, but data are needed to compare breath CO readings between smartphone-enabled and stand-alone monitors. The purpose of this study was to (1) determine the agreement between the mobile iCO (Bedfont Scientific Ltd) with two other monitors from the same manufacturer (Micro+ pro and Micro+ basic) and (2) determine optimal, monitor-specific, cotinine-confirmed abstinence cutoff values.

METHODS

Adult (≥18) smokers (n = 26) and nonsmokers (n = 21) provided three breath CO samples (using three different monitors) in each of 10 sessions, and urine cotinine was measured for gold standard determination of abstinence. CO comparisons (N = 437) were analyzed using regression-based Bland-Altman Analysis of Agreement; receiver operating characteristics curves were used to determine optimal abstinence cutoffs.

RESULTS

Bland-Altman analyses indicated that the iCO monitor provided higher CO results than both Micro+ monitors. Sensitivity and specificity analyses showed that the optimal CO cutoff for determining abstinence was <3 ppm for the Micro+ pro (88% sensitivity, 93% specificity) and Micro+ basic (83% sensitivity, 98% specificity), but was higher for the iCO (<6 ppm; 73% sensitivity, 100% specificity).

CONCLUSIONS

Relative to both Micro+ monitors, the smartphone-enabled iCO provided systematically higher CO values and required a higher cutoff to reliably determine smoking abstinence. This does not indicate that CO values obtained using the iCO are not valid; instead, these results suggest that monitor-specific abstinence cutoffs are needed to ensure accurate bioverification of smoking status.

IMPLICATIONS

Results from this study indicate that CO values from the smartphone-enabled iCO should not be used interchangeably with the stand-alone Micro+ pro and Micro+ basic, particularly when lower CO values (<10 ppm) are critical (ie, determination of abstinence vs confirming smoking status for study inclusion). Optimal CO cutoffs recommended for determining abstinence on Micro+ and iCO monitors are at <3 and <6 ppm, respectively.

The mobile-phone-based iCOTM Smokerlyzer®: Comparison with the piCO+ Smokerlyzer® among smokers undergoing methadone-maintained therapy

INTRODUCTION

The mobile-phone-based Bedfont iCO^TM Smokerlyzer^® is of unknown validity and reproducibility compared to the widely-used piCO⁺ Smokerlyzer^®. We aimed to compare the validity and reproducibility of the iCO^TM Smokerlyzer^® with the piCO⁺ Smokerlyzer^® among patients reducing or quitting tobacco smoking.

METHODS

Methadone-maintained therapy (MMT) users from three centers in Malaysia had their exhaled carbon monoxide (eCO) levels recorded via the piCO⁺ and iCO^TM Smokerlyzers^®, their nicotine dependence assessed with the Malay version of the Fagerström Test for Nicotine Dependence (FTND-M), and daily tobacco intake measured via the Opiate Treatment Index (OTI) Tobacco Q-score. Pearson partial correlations were used to compare the eCO results of both devices, as well as the corresponding FTND-M scores.

RESULTS

Among the 146 participants (mean age 47.9 years, 92.5% male, and 73.3% Malay ethnic group) most (55.5%) were moderate smokers (6-19 cigarettes/day). Mean eCO categories were significantly correlated between both devices (r=0.861, p<0.001), and the first and second readings were significantly correlated for each device (r=0.94 for the piCO⁺ Smokerlyzer^®, p<0.001; r=0.91 for the iCO^TM Smokerlyzer^®, p<0.001). Exhaled CO correlated positively with FTND-M scores for both devices. The post hoc analysis revealed a significantly lower iCO^TM Smokerlyzer^® reading of 0.82 (95% CI: 0.69–0.94, p<0.001) compared to that of the piCO⁺ Smokerlyzer^®, and a significant intercept of -0.34 (95% CI: -0.61 – -0.07, p=0.016) on linear regression analysis, suggesting that there may be a calibration error in one or more of the iCO^TM Smokerlyzer^® devices.

CONCLUSIONS

The iCO^TM Smokerlyzer^® readings are highly reproducible compared to those of the piCO⁺ Smokerlyzer^®, but calibration guidelines are required for the mobile-phone-based device. Further research is required to assess interchangeability.

Bangladesh Chars Tobacco Assessment Project (CTAP) 2018: a data note

OBJECTIVES

The Chars Tobacco Assessment Project 2018 is a holistic survey conducted in the chars (riverine islands) of Gaibandha in Northern Bangladesh, covering 985 households over 24 clusters. The survey was conducted with two objectives: (1) to assess levels of tobacco consumption and evaluate prevailing socio-economic, behavioral and health status of the chars population, and (2) to look at the effectiveness of advocacy campaigns to reduce tobacco consumption through behavioral nudges via randomized controlled trials (RCTs) in rural Bangladesh. The study site was purposively chosen due to its high tobacco consumption rate, and the geographical segregation of the chars aided in reducing spillovers for RCT design.

DATA DESCRIPTION

In addition to detailed information on tobacco (smoking and smokeless) consumption and perception, data was collected on: household composition, housing and plot ownership, consumption, risks and shocks coping, dowry, farm production, loans, savings and lending, labor income, asset holdings, migration and remittance, anthropometry, respiratory diseases, co-morbidities, reproductive history, risk and time preference. Unique to the dataset are carbon monoxide readings for accurate short term smoking measurement and FEV1 and PEF values for identification of long term lung damage. The data is representative only for the chars of Gaibandha.

The implications of high carbon monoxide levels in early pregnancy for neonatal outcomes

OBJECTIVES

The aim of this study was to examine the implications of increased maternal Breath Carbon Monoxide (BCO) levels at the first antenatal visit for subsequent birthweight (BW) and neonatal outcomes.

STUDY DESIGN

Secondary analysis of a prospective, observational study. Pregnant women aged ≥18years who understood English were recruited (n=250). However, only women who delivered a normally formed baby weighing ≥500g were analysed (n=234). At the first antenatal visit, a research questionnaire was completed and a BCO test was performed. Obstetric and neonatal data computerised by midwives at the first antenatal visit and updated after delivery were also analysed.

RESULTS

Results from the receiver operating characteristic (ROC) curve indicated the highest combined sensitivity and specificity for smoking was observed at a BCO cut-off level of 3ppm (sensitivity 85%, specificity 90%). Of the 234 women, 53 (22.6%) had a BCO ≥3ppm but only 36 (15.4%) disclosed smoking to the midwife on routine questioning. A further 23 (9.8%) were classified as non-disclosers based on a research questionnaire and/or a BCO measurement ≥3ppm. No relationship was found between the self-reported number of cigarettes daily in early pregnancy and BW (r=0.05, p=0.78). However, an inverse relationship was found between maternal BCO levels and BW (r=-0.31, p<0.001). BCO levels ≥3ppm in early pregnancy were associated with an increased risk of emergency caesarean section, low birth weight, BW <25th centile, fetal distress and having two or more adverse pregnancy events (all p<0.05). Smoking non-disclosers had babies with decreased BWs (-400.1g, 95% CI 141.1-659.0g, p<0.001), and higher rates of BW <25th centile (56.5% versus 25.3%, p<0.001), small-for-gestational-age (21.7% versus 9.1%, p<0.001) and fetal distress (39.1% versus 16.0%, p<0.01) compared to non-smokers Non-disclosers at the first antenatal visit also had a 22% higher rate of having two or more adverse pregnancy events (p<0.05).

CONCLUSION

The results showed that an increased BCO level was associated with a lower BW and increased risk of adverse pregnancy and neonatal outcomes. This strengthens the case for universal BCO screening at the first antenatal visit. A high BCO reading should be an indication for referral to stop smoking services referral and close fetal surveillance.

Clinical utility of exhaled carbon monoxide in assessing preoperative smoking status and risks of postoperative morbidity after esophagectomy

Whereas smoking constitutes a significant risk factor for postesophagectomy morbidity, there is no reliable method to assess the smoking status of patients prior to the procedure. Since exhaled carbon monoxide (CO) is an indicator of recent smoking, this paper hypothesizes that this is a useful parameter in assessing current smoking status and may help predict morbidity following esophagectomy. Sixty-nine patients, who had undergone elective three-incision esophagectomy with two- or three-field lymphadenectomy for esophageal cancer, were prospectively studied between February 2015 and September 2017. At surgical admission, they were asked about their smoking history, their exhaled CO levels were evaluated, and they were grouped into three based on their CO levels. These were 0 parts per million (ppm), >0 and <7 ppm, and ≥7 ppm. Their postoperative morbidity was also assessed. Approximately 13.5% of the patients showed high levels of exhaled CO ≥ 7 ppm, despite preoperatively reporting smoking cessation for over a month. Morbidities of the Clavien-Dindo classification (CDc) ≥ II increased as exhaled CO levels increased and severe morbidity of CDc ≥ IIIb frequently was observed in patients with exhaled CO levels ≥7 ppm. The logistic regression analysis showed that exhaled CO level ≥7 ppm was an independent risk factor for severe postesophagectomy morbidity. Overall, the results of this study suggest that exhaled CO levels may be useful in estimating current smoking status and that it may also help give an estimation of the risk of postesophagectomy morbidity.

A prospective, observational study investigating the use of carbon monoxide screening to identify maternal smoking in a large university hospital in Ireland

OBJECTIVES

This study evaluated breath carbon monoxide (BCO) testing in identifying maternal smokers as well as the difference between disclosers and non-disclosers of smoking status. We also investigated if other extrinsic factors affected the women's BCO levels in pregnancy.

DESIGN

A prospective observational study.

SETTING

A university obstetric hospital in an urban setting in Ireland.

PARTICIPANTS

Women (n=250) and their partners (n=54) were recruited at their first antenatal visit. Women <18 years and those who did not understand English were excluded. A booking history, including recording of smoking status, was collected by midwives. Following this, women were recruited and completed a detailed research questionnaire on smoking and extrinsic/environmental BCO sources. A BCO test was performed on both the woman and her partner.

PRIMARY AND SECONDARY OUTCOME MEASURES

The number of self-reported smokers and those that were positive on the BCO test. The characteristics of women who disclosed and did not disclose smoking status. The effect of extrinsic factors on the BCO test results.

RESULTS

Based on the receiver-operating characteristic curve, a BCO cut-off point of ≥3 ppm was the optimal level to identify ongoing smoking. At booking history, 15% of women reported as current smokers. Based on BCO levels ≥3 ppm combined with self-reported smoking in the research questionnaire, the rate increased to 25%. Non-disclosers had similar characteristics to non-smokers. No extrinsic factors affected maternal BCO levels.

CONCLUSIONS

Based on self-report and BCO levels, a quarter of women presenting for antenatal care continued to smoke, but only 60% reported their smoking to midwives. BCO measurement is an inexpensive, practical method of improving identification of maternal smoking, and it was not effected by extrinsic sources of BCO. Improved identification means more smokers can be supported to stop smoking in early pregnancy potentially improving the short-term and long-term health of both mother and child.

Validating Use of Internet-Submitted Carbon Monoxide Values by Video to Determine Quit Status

Introduction

Daily visits to biochemically verify continuous smoking abstinence via expired-air carbon monoxide (CO) may deter participation in cessation trials. One way to reduce need for daily visits while continuing to monitor abstinence success may be use of a recent procedure to verify abstinence from daily CO values via the Internet. This method requires participants submit to study staff video recordings of themselves correctly using a CO monitor. However, it has not been clearly demonstrated that those classified quit via Internet-submitted videos of CO would be reliably classified quit when assessed in lab.

Methods

Our study examined agreement in quit status from Internet-submitted CO values with quit status via CO collected in later same-day lab visits. Participants (n = 23) were from a short-term cessation study who agreed to record and submit videos of offsite CO testing, in addition to attending daily lab visits. All CO values were obtained via Bedfont pico+ Smokerlyzer monitors, with CO < 8 ppm indicating quit. During two 4-day practice quit attempts, a video was submitted before daily lab visits, up to eight videos each.

Results

Of the total of 150 videos submitted, 97 videos indicated "not quit" and 53 "quit." Cohen's Kappa indicated substantial agreement in quit status between assessments, 0.70, p < .001, as 85% of the videos indicating "quit" CO were also "quit" CO in lab.

Conclusions

To our knowledge, these results are the first validation of daily Internet-submitted CO values to confirm daily quit status, supporting the utility of this approach for close monitoring of continuous abstinence.

Implications

This study compared consistency between quit status from CO values submitted over the Internet and quit status via CO collected in later same-day lab visits. Findings indicate substantial agreement in quit status between these two methods of CO assessment. Our results validate the use of Internet-submitted CO values to verify daily quit status. This method can be used in future cessation trials as a means to biochemically validate continuous abstinence without the burden of daily lab visits or relying on self-report of recent smoking lapses.

ANALYSIS OF AGREEMENT BETWEEN EXPIRED-AIR CARBON MONOXIDE MONITORS

Introduction

The current study examined the level of agreement in expired-air carbon monoxide (CO) values, focusing especially on those confirming abstinence, between the two most commonly used CO monitors, the Vitalograph BreathCO and the Bedfont piCO+ Smokerlyzer.

Methods

Expired-air samples were collected via both monitors from adult dependent smokers (44 M, 34 F) participating in studies using CO values to confirm abstinence durations of: 24 hours, 12 hours, or no abstinence. All met DSM-IV nicotine dependence criteria and had a mean (SD) Fagerström Test of Cigarette Dependence score of 5.1 (1.8). Paired data collected across multiple visits were analyzed by regression-based Bland-Altman method of Limits of Agreement.

Findings

Analysis indicated a lack of agreement in CO measurement between monitors. Overall, the Bedfont monitor gave mean (±SEM) readings 3.83 (±.23) ppm higher than the Vitalograph monitor. Mean differences between monitors were larger for those ad lib smoking (5.65±.38 ppm) than those abstaining 12-24 hours (1.71±.13 ppm). Yet, there also was not consistent agreement in classification of 24 hour abstinence between monitors.

Conclusions

Systematic differences in CO readings demonstrate these two very common monitors may not result in interchangeable values, and reported outcomes in smoking research based on CO values may depend on the monitor used.