Smoking, Lung Cancer Stage, and Prognostic Factors-Findings from the National Lung Screening Trial

BACKGROUND

Low-dose computed tomography (LDCT) increases the early detection of lung cancer. Identifying modifiable behaviors that may affect tumor progression in LDCT-detected patients increases the likelihood of long-term survival and a good quality of life.

METHODS

We examined cigarette smoking behaviors on lung cancer stage, progression, and survival in 299 ever-smoking patients with low-dose CT-detected tumors from the National Lung Screening Trial. Univariate and multivariate Cox models were used to estimate the hazard ratio (HR) for smoking variables on survival time.

RESULTS

Current vs. former smokers and early morning smokers (≤5 min after waking, i.e., time to first cigarette (TTFC) ≤ 5 min) had more advanced-stage lung cancer. The adjusted HR for current vs. former smokers was 1.3 (95% confidence interval [CI] 0.911-1.98, p = 0.136) for overall survival (OS) and 1.3 (0.893-1.87, p = 0.1736) for progression-free survival (PFS). The univariate hazard ratios for TTFC ≤ 5 min vs. >5 min were 1.56 (1.1-2.2, p = 0.013) for OS and 1.53 (1.1-2.12, p = 0.01) for PFS. Among current smokers, the corresponding HRs for early TTFC were 1.78 (1.16-2.74, p = 0.0088) and 1.95 (1.29-2.95, p = 0.0016) for OS and PFS, respectively. In causal mediation analysis, the TTFC effect on survival time was mediated entirely through lung cancer stage.

CONCLUSION

The current findings indicate smoking behaviors at diagnosis may affect lung cancer stage and prognosis.

Time to First Cigarette: A Potential Clinical Screening Tool for Nicotine Dependence

OBJECTIVES

The time to first cigarette (TTFC) of the day has been identified as the best single-item indicator of nicotine dependence. However, TTFC has not been extensively used in clinical settings and is not a criterion for tobacco use disorder, perhaps due to a lack of information about TTFC's predictive value. This review provides a synthesis of the accumulating literature on TTFC's relationships with nicotine dependence, identify gaps, and inform future clinical and epidemiologic research of potential uses of TTFC.

METHODS

A systematic review of the literature was conducted using PubMed, Google Scholar, and Web of Science ISI databases. We identified 16 articles examining the relation between TTFC and negative outcomes associated with high levels of nicotine addiction and Tobacco Use Disorders (eg, high levels of nicotine and toxicant exposure, progressive use over time, failed cessation, head-and-neck cancers).

RESULTS

Earlier TTFC was consistently associated with greater likelihood of cessation failure and relapse, and higher levels of biomarkers of tobacco exposure. Several of these associations were found among both adult and adolescent smokers, and remained even after accounting for smoking behaviors (eg, cigarettes/day).

CONCLUSIONS

Earlier TTFC is a key indicator of greater nicotine dependence. Knowledge of a smoker's TTFC may allow clinicians to accurately inform smokers of health risks and assign greater resources during cessation attempts. Smokers may be able to use TTFC to self-select cessation aids and accurately assess their unique smoking-related health risks. TTFC may be a better item than cigarettes/day for accurately quantifying dependence and risk in epidemiologic studies.

Black Light Smokers: How Nicotine Intake and Carcinogen Exposure Differ Across Various Biobehavioral Factors

OBJECTIVE

The study objective was to identify biobehavioral variables associated with greater intake of nicotine and a tobacco carcinogen among Black light smokers who smoke 1 to 10 cigarettes per day (CPD).

METHODS

We analyzed baseline data collected from 426 Black light smokers enrolled in Kick It at Swope III (KIS III), a smoking cessation trial for Black smokers. We examined differences in concentrations of tobacco biomarkers, including urinary total nicotine equivalents (TNE) and total 4-(methylnitrosamino)-1-(3)pyridyl-1-butanonol (NNAL; a human carcinogen), across gender, age, plasma nicotine metabolite ratio (NMR), CPD, and measures of tobacco dependence, including time to first cigarette (TFC), using ANOVA.

RESULTS

Tobacco biomarker levels were significantly higher among those who smoked more CPD (6-10 vs 1-5 CPD) and those with greater reported physical dependence on tobacco. Concurrently, those who smoked 1-5 CPD smoked each cigarette more intensely than those who smoked 6-10 CPD. While we found no gender differences overall, among those who smoked 1-5 CPD, women had higher NNAL levels compared to men. The rate of nicotine metabolism, measured by the nicotine metabolite ratio, was not significantly related to TNE or NNAL levels.

CONCLUSION

Among Black Light smokers, higher cigarette consumption and greater physical dependence-but not rate of nicotine metabolism, menthol use, or socioeconomic status-were associated with greater toxicant exposure and thus a likely increased risk of tobacco-related diseases. The lack of data on light smokers, and specifically on Blacks, make this observation important given the disproportionate burden of lung cancer in this population.

Household Smoking Restrictions Relate To Time To First Cigarette Smoked In The Morning

Introduction

The time a smoker waits until the first cigarette of the morning is often used as a measure of dependence with the rationale that more dependent smokers will smoke sooner upon waking than will less dependent smokers after going several hours without a cigarette overnight.

Aims

We sought to examine the relationship between time-to-first-cigarette (TTFC) and household smoking restrictions in two independent samples.

Methods

Two samples of smokers, one treatment-seeking community sample (N = 433) and one non-treatment-seeking sample of smokers with serious mental illness (i.e., Schizophrenia, Schizoaffective Disorder, or Bipolar I Disorder) (N = 94), provided information on cigarette dependence with the Fagerström Test for Nicotine Dependence and on household smoking restrictions.

Results

Half (50%) of smokers with serious mental illness and 36.7% of smokers from the general population reported that there were no limitations to smoking in their home. Household smoking restrictions were significantly and positively related to TTFC in both samples.

Conclusions

These data indicate that greater attention to TTFC may be warranted. The TTFC item is intended to measure dependence based on the premise that greater dependence should be associated with shorter TTFC. If TTFC is related to a household smoking ban, however, this item may not be assessing dependence as intended in some cases.

Plasma cotinine levels in cigarette smokers: impact of mental health and other correlates

BACKGROUND/AIMS

We examined in cigarette smokers whether cotinine was associated with depressive and/or anxiety disorders.

METHODS

Data were derived from 1,026 smoking adults with and without depressive and/or anxiety disorders participating in the Netherlands Study of Depression and Anxiety (NESDA). Depressive and anxiety disorders were ascertained with the DSM-IV Composite International Diagnostic Interview. Cigarette consumption was inquired about during an interview. Cotinine was assessed in plasma.

RESULTS

Currently depressed and/or anxious smokers (n=692) reported smoking a higher number of cigarettes per day (CPD) than smokers with a remitted disorder (n=190) and smokers with no lifetime disorder (n=144). After controlling for CPD and other covariates, depressed and/or anxious smokers had lower cotinine levels compared to smokers with no lifetime disorder (B=-56.0, p=0.001). In the full regression model, CPD was positively associated with cotinine levels, whereas current depression and/or anxiety and high body mass index were inversely associated with cotinine.

CONCLUSION

After considering CPD, the presence of current depressive and/or anxiety disorders was associated with lower cotinine levels, which may point to a different smoking topography or a faster cotinine metabolism in individuals with affective disorders. The latter could help to explain the higher number of cigarettes smoked and poorer cessation rates among depressed or anxious patients.

Developmental nicotine exposure alters AMPA neurotransmission in the hypoglossal motor nucleus and pre-Botzinger complex of neonatal rats

Developmental nicotine exposure (DNE) impacts central respiratory control in neonates born to smoking mothers. We previously showed that DNE enhances the respiratory motor response to bath application of AMPA to the brainstem, although it was unclear which brainstem respiratory neurons mediated these effects (Pilarski and Fregosi, 2009). Here we examine how DNE influences AMPA-type glutamatergic neurotransmission in the pre-Bötzinger complex (pre-BötC) and the hypoglossal motor nucleus (XIIMN), which are neuronal populations located in the medulla that are necessary for normal breathing. Using rhythmic brainstem slices from neonatal rats, we microinjected AMPA into the pre-BötC or the XIIMN while recording from XII nerve rootlets (XIIn) as an index of respiratory motor output. DNE increased the duration of tonic activity and reduced rhythmic burst amplitude after AMPA microinjection into the XIIMN. Also, DNE led to an increase in respiratory burst frequency after AMPA injection into the pre-BötC. Whole-cell patch-clamp recordings of XII motoneurons showed that DNE increased motoneuron excitability but did not change inward currents. Immunohistochemical studies indicate that DNE reduced the expression of glutamate receptor subunits 2 and 3 (GluR2/3) in the XIIMN and the pre-BötC. Our data show that DNE alters AMPAergic synaptic transmission in both the XIIMN and pre-BötC, although the mechanism by which this occurs is unclear. We suggest that the DNE-induced reduction in GluR2/3 may represent an attempt to compensate for increased cell excitability, consistent with mechanisms underlying homeostatic plasticity.

Menthol smoking in relation to time to first cigarette and cotinine: results from a community-based study

Smokers who have their first cigarette shortly after waking, an indicator of nicotine dependence, have substantially higher cotinine levels. There is controversy regarding the role of menthol in nicotine dependence. We hypothesized that menthol smokers have a shorter time to first cigarette (TTFC), and tested whether any statistical association actually reflects increased dependence by measuring nicotine uptake (e.g. cotinine) in the same group of smokers. A cross-sectional community-based study was conducted that included 495 black and white daily cigarette smokers. Results showed a trend between menthol smoking and a shorter TTFC (P < 0.04 in blacks). Menthol was not an independent predictor of cotinine or an effect modifier with TTFC on cotinine levels in blacks and whites. These results show that while menthol in tobacco is associated with an indicator of nicotine dependence in blacks, menthol was not associated with biological uptake of nicotine in black and white smokers.