Salivary cotinine concentration versus self-reported cigarette smoking: Three patterns of inconsistency in adolescence.

The present study examined the extent and sources of discrepancies between self-reported cigarette smoking and salivary cotinine concentration among adolescents. The data are from household interviews with a cohort of 1,024 adolescents from an urban school system. Histories of tobacco use in the last 7 days and saliva samples were obtained. Logistic regressions identified correlates of three inconsistent patterns: (a) Pattern 1-self-reported nonsmoking among adolescents with cotinine concentration above the 11.4 ng/mg cutpoint (n = 176), (b) Pattern 2-low cotinine concentration (below cutpoint) among adolescents reporting having smoked within the last 3 days (n = 155), and (c) Pattern 3-high cotinine concentration (above cutpoint) among adolescents reporting not having smoked within the last 3 days (n = 869). Rates of inconsistency were high among smokers defined by cotinine levels or self-reports (Pattern 1 = 49.1%; Pattern 2 = 42.0%). Controlling for other covariates, we found that reports of nonsmoking among those with high cotinine (Pattern 1) were associated with younger age, having few friends smoking, little recent exposure to smokers, and being interviewed by the same interviewer as the parent and on the same day. Low cotinine concentration among self-reported smokers (Pattern 2) was negatively associated with older age, being African American, number of cigarettes smoked, depth of inhalation, and exposure to passive smoke but positively associated with less recent smoking and depressive symptoms. High cotinine concentrations among self-reported nonsmokers was positively associated with exposure to passive smoke (Pattern 3). The data are consonant with laboratory findings regarding ethnic differences in nicotine metabolism rate. The inverse relationship of cotinine concentration with depressive symptoms has not previously been reported. Depressed adolescent smokers may take in smaller doses of nicotine than nondepressed smokers; alternatively, depressed adolescents may metabolize nicotine more rapidly.     

Preliminary examination of tobacco withdrawal in adolescent smokers during smoking cessation treatment

Tobacco withdrawal symptoms have been shown to play a significant role in mediating relapse to smoking in adult smokers; however, few prospective studies have examined the course of tobacco withdrawal symptoms over time and their connection to lapse in adolescent smokers. Withdrawal symptoms were assessed weekly for 4 weeks in a sample of adolescent smokers participating in a pilot cessation intervention. Adolescent smokers experienced an exacerbation in overall withdrawal symptoms, particularly of cravings and restlessness, although symptoms were generally mild. The course of symptoms was different for boys and girls: Girls generally experienced a peak and subsequent decline in symptoms early in the establishment of abstinence, whereas boys experienced a constant level of symptoms that did not decline over the 4 weeks. Finally, withdrawal symptoms experienced on quit day were not related to lapse to smoking during the course of treatment for either boys or girls. These results suggest that although withdrawal symptoms may be uncomfortable, they may not be the most salient to a lapse to smoking for adolescent smokers attempting to quit. These findings have direct implications for the design and implementation of treatment of nicotine dependence in adolescent smokers.     

Higher nicotine and carbon monoxide levels in menthol cigarette smokers with and without schizophrenia.

This study examined whether smoking menthol cigarettes was associated with increased biochemical measures of smoke intake. Expired carbon monoxide (CO) and serum nicotine and cotinine were measured in 89 smokers with schizophrenia and 53 control smokers immediately after smoking an afternoon cigarette. Serum nicotine levels (27 vs. 22 ng/ml, p = .010), serum cotinine levels (294 vs. 240 ng/ml, p = .041), and expired CO (25 vs. 21 ppm, p = .029) were higher in smokers of menthol compared with nonmenthol cigarettes, with no differences in 3-hydroxycotinine/cotinine ratios between groups when controlling for race. Backward stepwise linear regression models showed that, in addition to having a diagnosis of schizophrenia, smoking menthol cigarettes was a significant predictor of nicotine and cotinine levels. Individuals with schizophrenia or schizoaffective disorder smoked more generic or discount value brands (Basic, Doral, Monarch, USA, Wave, others) compared with control smokers (28% vs. 6%, p = .002) but did not smoke more brands with high nicotine delivery as estimated by the U.S. Federal Trade Commission method. Although rates of mentholated cigarette smoking were not higher in smokers with schizophrenia overall, they were significantly higher in non-Hispanic White people with schizophrenia compared with controls of the same ethnic/racial subgroup (51% vs. 28%, p<.0001). The higher exhaled CO in menthol smokers suggests that the higher nicotine levels are at least partly related to increased intake of smoke from menthol cigarettes, although menthol-mediated inhibition of nicotine metabolism also may be a factor. Menthol is an important cigarette additive that may help explain why some groups have lower quit rates and more smoking-caused disease.     

Smoke constituent exposure and smoking topography of adolescent daily cigarette smokers.

Adolescent smoking prevalence is a major health concern, with 24.4% reporting smoking in the past 30 days and 15.8% considered daily smokers. The purpose of this study was to characterize biobehavioral nicotine dependence, smoke constituent exposure and smoking topography in adolescent daily smokers. Relationships among biological markers of nicotine dependence (nicotine boost, carbon monoxide [CO] boost and cotinine levels) with existing self-report measures (modified Fagerstr?m Tolerance Questionnaire [mFTQ] and the motivations for smoking scale) were examined. Gender differences were characterized. Fifty adolescents 13-18 years old were recruited for the study, 50% female. CO, plasma nicotine levels pre- and postcigarette, cotinine, and smoking topography were measured during a smoking bout with participant's usual cigarette. Average CO boost, pre- to postcigarette was 7.2 + 3.6 ppm, baseline cotinine level averaged 224.0 +/- 169.6 ng/ml and nicotine boost averaged 23.4 +/- 21.7 ng/ml. Mean puffs per cigarette was 14.2 +/- 6.3. Males had significantly higher total puff volumes, but similar smoke constituent exposure to females, and higher handling of cigarettes as smoking motive. In regression analysis, 35% of variance in tobacco use, as indicated by baseline cotinine concentration, was explained by maximum puff duration, postcigarette CO level, and nicotine dependence, as measured by the mFTQ. Results indicated adolescents had considerable smoke constituent exposure and nicotine dependence suggesting the importance of appropriate smoking cessation treatment.     

Cotinine levels in relation to smoking behavior and addiction in young adolescent smokers.

The goal of this study was to identify associations among self-reported nicotine exposure, nicotine addiction, and actual nicotine intake as measured by salivary cotinine levels in adolescent smokers. A total of 170 adolescent smokers with a mean age of 15 years were recruited from seven northern Californian public high schools. Data were collected on smoking behaviors, addiction, craving, and withdrawal. Nicotine dependence was assessed using a modified teen Fagerstr?m Tolerance Questionnaire (mtFTQ), a modified Nicotine Dependence Syndrome Scale (mNDSS), and a simple self-rating. Withdrawal was assessed using the Minnesota Withdrawal Questionnaire, and craving was assessed using a survey created by the authors. Salivary cotinine levels were collected from and analysed in participants who self-identified as smokers; data from the 54 participants who smoked in the past 4 days and whose salivary cotinine levels were greater than 0.1 ng/ml were used in the analysis. Among this group of adolescent smokers, the mean number of cigarettes smoked per day was 3.51 (SD = 3.44) and the mean level of salivary cotinine was 44.1 ng/ml (Mdn = 24.2). Even at this low level of nicotine exposure, cotinine was highly correlated with measures of nicotine dependence such as the mtFTQ (r = 0.497, p = .001), NDSS (r = 0.439, p = .002), timing of craving in the morning (r = -0.601, p = .000), and self-rated addiction (r = 0.562, p = .000). Most interesting, cotinine levels reached a plateau at around 4-5 cigarettes/day.     

Nicotine, cotinine, withdrawal, and craving patterns during smoking and nicotine nasal spray use: results from a pilot study with African American men.

Nicotine intake via smoking is highly variable. Individualized dosing of nicotine replacement therapy (NRT) may improve product efficacy, but a better understanding of the within-day and within-subject relationships between smoking, NRT use, nicotine and cotinine concentrations in blood, and cravings and withdrawal symptoms is needed to inform dosing algorithms. A pilot study was undertaken to collect data on these relationships and to assess the feasibility of the methods needed for this type of research, including a sophisticated statistical modeling technique (a two-part mixed-effects model with correlated random effects that accounts for clumping at zero). Because nicotine metabolism varies by gender and race, the sample was homogeneous with respect to these characteristics. In a within-subjects study, 27 African American adult male smokers carried a computerized cigarette dispenser for 1 week, capturing the time each cigarette was smoked. Subjects then entered an inpatient setting for 1 day of scheduled smoking (matched to data from the cigarette dispenser to create an ecologically valid schedule) and 4 days of ad libitum nicotine nasal spray use, while tobacco abstinent. Eight times per day, at 2-hour intervals, blood was drawn and ratings of cigarette cravings and withdrawal symptoms were obtained. On average, subjects used less than half of the manufacturer's recommended minimum daily dose of nicotine nasal spray. Large differences in nicotine and cotinine levels were observed between individuals. When predicting nicotine, cotinine, withdrawal, and cravings, we observed significant interactions between route of nicotine intake and a variety of independent variables.     

Determinants of salivary cotinine levels among current smokers in Mexico.

The present study describes salivary cotinine levels and their relationship to cigarettes smoked per day in Mexican smokers. Using a sampling strategy based on the number of cigarettes per day, we recruited 1,222 smokers from Mexico City and the state of Morelos in Mexico during 1999. Smoking behaviors and other factors known to affect nicotine intake and cotinine level were identified in an interview using a standardized questionnaire. Salivary cotinine was measured by capillary gas chromatography with nitrogen-phosphorus detection. We used generalized additive models to describe the relationship between salivary cotinine levels and variables of interest. The mean age of the population was 39.7 years (SD=15.6 years), with a mean cotinine level of 194.7 ng/ml (SD=134.8; range=10.1-767). Participants smoked a mean of 15.5 cigarettes per day (SD=11.3). Salivary cotinine and cigarettes smoked per day were positively related, although the association was not linear, flattening above 20 cigarettes per day. After adjusting for cigarettes per day, we found that significant predictors of cotinine levels included age, body mass index, cigarette producer, and smoking behavior variables. These results may have implications for dosing with nicotine medications to aid smoking cessation in Mexican smokers and suggest that whether the cigarette is labeled light or regular has no relationship to nicotine dose from smoking cigarettes.     

Sex-related differences in serum cotinine concentrations in daily cigarette smokers

Self-reported use of cigarettes generally underestimates the true cigarette exposure of smokers. Serum cotinine is considered the best biomarker to evaluate tobacco exposure. This study determined whether or not there were any significant differences in serum cotinine concentrations between men and women when they reported smoking the same number of cigarettes per day. We analyzed cotinine and tobacco consumption data on 680 women and 840 men, aged 20 years or older, who smoked at least 100 cigarettes during their lifetime and were still actively smoking at the time of the National Health and Nutrition Examination Surveys (1999-2002). Overall, compared with men, women reported smoking fewer cigarettes per day (16.1 vs. 18.7, p<.001) and had lower serum cotinine concentrations (1163.3 nmol/L vs. 1343.9 nmol/L, p<.001). Women were more likely than men to smoke filtered (p = .018) and mentholated (p<.001) cigarettes. After adjustment for the number of cigarettes smoked per day, age, race, body mass index, poverty status, the use of either menthol or regular cigarettes, and the nicotine content in cigarettes, female compared with male smokers had lower serum cotinine concentrations (difference of 117.6 nmol/L; 95% CI = 42.6-192.6, p = .003). The difference was particularly notable in moderate to heavy smokers (i.e., those who smoked more than 15 cigarettes/day). These findings indicate that significant sex-related differences exist in serum cotinine levels among smokers, which suggests that self-reports may overestimate cigarette exposure in women compared with men.     

Waterpipe smoking and nicotine exposure: a review of the current evidence.

The waterpipe, also known as shisha, hookah, narghile, goza, and hubble bubble, has long been used for tobacco consumption in the Middle East, India, and parts of Asia, and more recently has been introduced into the smokeless tobacco market in western nations. We reviewed the published literature on waterpipe use to estimate daily nicotine exposure among adult waterpipe smokers. We identified six recent studies that measured the nicotine or cotinine levels associated with waterpipe smoking in four countries (Lebanon, Jordan, Kuwait, and India). Four of these studies directly measured nicotine or cotinine levels in human subjects. The remaining two studies used smoking machines to measure the nicotine yield in smoking condensate produced by the waterpipe. Meta-analysis of the human data indicated that daily use of the waterpipe produced a 24-hr urinary cotinine level of 0.785 microg/ml (95% CI = 0.578-0.991 microg/ml), a nicotine absorption rate equivalent to smoking 10 cigarettes/day (95% CI = 7-13 cigarettes/day). Even among subjects who were not daily waterpipe smokers, a single session of waterpipe use produced a urinary cotinine level that was equivalent to smoking two cigarettes in one day. Estimates of the nicotine produced by waterpipe use can vary because of burn temperature, type of tobacco, waterpipe design, individual smoking pattern, and duration of the waterpipe smoking habit. Our quantitative synthesis of the limited human data from four nations indicates that daily use of waterpipes produces nicotine absorption of a magnitude similar to that produced by daily cigarette use.     

Cigarette nicotine yields and nicotine intake among Japanese male workers

OBJECTIVES: To analyse brand nicotine yield including "ultra low" brands (that is, cigarettes yielding less-than-or-equal 0.1 mg of nicotine by Federal Trade Commission (FTC) methods) in relation to nicotine intake (urinary nicotine, cotinine and trans-3'-hydroxycotinine) among 246 Japanese male smokers. DESIGN: Cross sectional study. SETTING: Two companies in Osaka, Japan. SUBJECTS: 130 Japanese male workers selected randomly during their annual regular health check up and 116 Japanese male volunteers taking part in a smoking cessation programme. MAIN OUTCOME MEASUREMENTS: Subjects answered a questionnaire about smoking habits. Following the interview, each participant was asked to smoke his own cigarette and, after extinguishing it, to blow expired air into an apparatus for measuring carbon monoxide concentration. Urine was also collected for the assays of nicotine metabolites. RESULTS: We found wide variation in urinary nicotine metabolite concentrations at any given nicotine yield. Based on one way analysis of variance (ANOVA), the urinary nicotine metabolite concentrations of ultra low yield cigarette smokers were significantly lower compared to smokers of high (p = 0.002) and medium yield cigarettes (p = 0.017). On the other hand, the estimated nicotine intake per ultra low yield cigarette smoked (0.59 mg) was much higher than the 0.1 mg indicated by machine. CONCLUSIONS: In this study of Japanese male smokers, actual levels of nicotine intake bore little relation to advertised nicotine yield levels. Our study reinforces the need to warn consumers of inappropriate advertisements of nicotine yields, especially low yield brands.     

吸烟者转抽加热卷烟的抽吸行为和烟碱暴露

为研究吸烟者转抽加热卷烟后抽吸行为和烟碱暴露水平的变化,招募50名抽吸卷烟的志愿者,分为两组,分别转抽加热卷烟IQOS和国内加热卷烟M。转抽前后通过问卷调查获得志愿者的基线资料,使用CReSS吸烟行为记录仪测试吸烟行为参数,采用HPLC-MS/MS测定志愿者基线和转抽后尿样中的烟碱暴露生物标志物。结果表明:①志愿者转抽加热卷烟后抽吸行为基本保持不变,抽吸容量和抽吸时间均未发生显著性改变,但抽吸间隔明显缩短,两组志愿者抽吸卷烟时抽吸间隔分别为（14.3±8.0）s和（15.3±9.0）s,转抽加热卷烟后抽吸间隔分别为（9.8±8.3）s和（9.7±5.4）s。②转抽后志愿者尿液中烟碱总代谢物和可替宁等烟碱暴露生物标志物的浓度水平也未发生显著性改变。③转抽IQOS后志愿者的抽吸行为与转抽M后的志愿者没有明显差异,两组志愿者尿液中烟碱总代谢物和可替宁的水平也近似。      

The influence of gender, race, and menthol content on tobacco exposure measures.

Research has suggested that race, gender, and menthol cigarette use influence tobacco-smoke exposure measures and smoking-related disease risk. For example, a high proportion of Black smokers prefer menthol cigarettes and, despite smoking fewer cigarettes per day (CPD) than do Whites, tend to have higher cotinine levels. Additionally, Black males are more at risk for smoking-related lung cancer. High cotinine levels and smoking menthol cigarettes may lead to higher toxin intake, which contributes to increased disease risk. We explored the relationship between tobacco exposure variables (i.e., cotinine, CPD, carbon monoxide [CO], nicotine content, and nicotine dependence) with respect to race, gender, and menthol content in a sample of 307 smokers recruited from the greater Boston area to participate in a smoking cessation treatment trial. The pattern of correlations between tobacco exposure measures and cotinine showed a consistently positive correlation between cotinine and CO in all smokers and a correlation between cotinine and CPD in those who smoked nonmenthol cigarettes. Cotinine and CPD correlations varied by gender and race among menthol cigarette smokers. Consistently, we found a significant gender x race x menthol interaction on salivary cotinine level as well as cotinine/CPD ratio. These findings suggest that the relationship between number of cigarettes consumed and salivary cotinine is more complex than previously believed. It is not sufficient to look at race alone; researchers and clinicians need to look at race and gender concurrently, as well as type of cigarette consumed.     

Nicotine metabolism in pregnant and nonpregnant rabbits.

Smoking during pregnancy remains a major public health concern and is associated with numerous adverse effects. Recently the clearance of nicotine and cotinine was shown to be substantially increased in pregnant women compared with nonpregnant controls. The present study investigated the usefulness of the rabbit for studying the molecular basis for the observed changes in nicotine and cotinine disposition during pregnancy. Nicotine was largely metabolized to cotinine in rabbit liver microsomes (approximately 50% of total metabolism); significant amounts of nicotine-N'-oxide and nornicotine also were detected. The conversion of nicotine to cotinine also was detected in rabbit placental and fetal liver microsomes, albeit at only a fraction of the rate found in adult rabbit liver microsomes. The major products of cotinine metabolism in rabbit liver microsomes were 5'-hydroxycotinine, cotinine-N'-oxide, and norcotinine. Differences between human and rabbit liver were most apparent for cotinine. The major human metabolite, 3'-hydroxycotinine, was formed at only low levels in rabbit liver microsomes. Pregnancy had no effect on the metabolism of nicotine or on the expression of CYP2A6 immunoreactive proteins in rabbit liver microsomes. These studies provide a complete quantitative assessment of nicotine metabolism in rabbit liver microsomes and suggest that the rabbit may not be an appropriate animal model to study the effects of pregnancy on nicotine and cotinine metabolism. However, a molecular understanding of these effects is essential for prediction of the pharmacological and toxicological consequences of smoking during pregnancy.     

头发中烟碱和可替宁的超高效液相色谱测定

采用5%NaOH水溶液超声萃取-超高效液相色谱法同时测定了36个主动吸烟者头发样品和10个被动吸烟者头发样品中的烟碱和可替宁含量。结果表明:①烟碱和可替宁的RSD分别为3.52%和2.99%;回收率均为98.5%～101.6%;②主动吸烟者和被动吸烟者头发样品中均检测到烟碱,而可替宁只在主动吸烟者头发样品中检出;③主动吸烟者头发中的烟碱含量的高低主要是由其烟龄和日均吸烟支数决定的,而与其生理年龄关系较小;④主动吸烟者头发中的可替宁含量高低主要是由其烟龄决定的,而与其日均吸烟支数和生理年龄关系较小。该法操作简便,准确性高,重复性好,可用于批量头发样品中烟碱和可替宁含量的快速分析。     

Urinary tobacco-specific nitrosamines and 4-aminobiphenyl hemoglobin adducts measured in smokers of either regular or light cigarettes.

Cigarette brands may differ in their reported yields of "tar" as determined by the Federal Trade Commission smoking-machine method. Brands with relatively lower tar and nicotine yields often are described as light cigarettes. Smokers of light cigarettes generally maintain a nicotine intake comparable to that of smokers of regular cigarettes through compensatory smoking behaviors, but similar data have not been reported for carcinogen biomarkers. In the present study we measured serum cotinine concentrations (a marker of nicotine exposure), urinary levels of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL, a tobacco-specific nitrosamine [TSNA]), and hemoglobin adducts of 4-aminobiphenyl (4-ABP) in 150 smokers of either regular or light cigarettes. The TSNA and aromatic amines are known carcinogens in tobacco smoke. Multiple regression models were developed for each of the analytes and used to calculate adjusted geometric means. We found no significant differences in the levels of these biomarkers between customary users of light and regular cigarettes. Thus the concentrations of the carcinogen biomarkers NNAL and 4-ABP in the smokers who regularly smoked light cigarettes were essentially the same as those in the smokers who chose regular cigarettes.     

Passive smoking in the home: plasma cotinine concentrations in non-smokers with smoking partners

BACKGROUND: Risks of lung cancer and of heart disease attributable to passive smoking have been evaluated mainly in non-smokers married to smokers, but there has been little quantitative assessment of the extent of exposure in marriage partners as indicated by markers of inhaled smoke dose. OBJECTIVE: To relate plasma cotinine concentrations in non-smoking English adults to the smoking behaviour of their partners and to demographic and other factors. DATA: Population survey. Data from two years (1994 and 1996) of the Health Survey for England. MAIN OUTCOME MEASURES: Plasma cotinine concentrations in non-smoking adults married to or cohabiting with a partner. RESULTS: There was a strong dose-response relation between cotinine concentrations in non-smoking adults and the smoking behaviour of their partners, rising from a geometric mean of 0.31 ng/ml in those with non-smoking partners to 1.99 ng/ml in those whose partners smoked 30 or more cigarettes per day. In addition, exposure was greater in men, in the autumn and winter, and in those living in more disadvantaged circumstances, and there was an increasing gradient of exposure from the south to the north of the country. On average, cotinine concentrations in non-smokers with a smoking partner were 0.6-0.7% of those in cigarette smokers. CONCLUSIONS: If cotinine is taken as a measure of risk relevant dose, the implied increase in risk of lung cancer in non-smokers with smoking partners is consistent with the risk observed in epidemiological studies. Smoking by partners in the home is a major source of non-smoking adults' exposure to passive smoking.     

Adolescent smoking trajectories and nicotine dependence.

The present study correlates empirically constructed prospective adolescent smoking trajectories with indicators of nicotine dependence assessed in adolescence and in adulthood. Excluding individuals who reported no smoking during repeat assessment (nonadopters), we identified five smoking trajectory groups: experimenters (n=116, 48.5%), late increasers (n=39, 16.3%), early increasers (n=37, 15.5%), quitters (n=22, 9.2%), and persistent smokers (n=25, 10.5%). Higher frequency of nicotine dependence symptoms in adolescence occurred in the quitters and persistent smokers groups, who smoked at higher levels relative to the experimenters, late increasers, and early increasers groups, who reported a similar frequency of nicotine dependence symptoms and smoked at low levels. Lifetime nicotine dependence was assessed in adulthood in lifetime daily smokers using the Fagerstr?m Test for Nicotine Dependence (FTND) and the Nicotine Dependence Scale (NDS). Lifetime FTND levels were similar across trajectory groups. Relative to experimenters, all remaining smoking trajectory groups had higher NDS levels that were similar to one another. These results suggest that higher levels of adolescent nicotine dependence were associated with heavier smoking trajectory groups, and that regardless of trajectory group membership, smoking more than a few cigarettes per week throughout adolescence resulted in similar levels of lifetime nicotine dependence as measured by the FTND and NDS.     

Effects of smoking cessation and reduction in asthmatics.

The present study examined the effect of smoking reduction and cessation on asthma regulation and biomarkers of exposure to cigarette smoke. In a prospective open design, we allocated 220 asthmatics among three groups: (a) Smoking reduction (reducers), with the aim of smoking fewer than seven cigarettes per day, (b) complete smoking cessation (abstainers), or (c) continuation of usual smoking (continuing smokers). Subjects used nicotine chewing gum or an oral nicotine inhaler to promote reduction and cessation. We monitored changes in the biomarkers carbon monoxide, cotinine, and thiocyanate, and in peak flow, medicine use, bronchial reactivity, and asthma symptoms. The analysis used the three outcome groups, regardless of original allocation to treatment groups. At 4 months, analysis of abstainers (n = 27), reducers (n = 33), and continuing smokers (n = 50) showed marked, statistically significant decreases in expired carbon monoxide of 17 ppm (abstainers) and 15 ppm (reducers); in plasma cotinine of 124 ng/ml (abstainers) and 122 ng/ml (reducers); and in plasma thiocyanate of 5.03 ng/ml (abstainers) and 3.74 ng/m (reducers). For abstainers, we observed improvements in the asthma-specific quality-of-life score, and reductions in self-reported day and night use of rescue beta2-agonists, in doses of inhaled corticosteroids, in daytime asthma symptoms, and in bronchial hyperreactivity. For reducers, smaller improvements occurred for night use of rescue beta2-agonists, doses of inhaled corticosteroids, and bronchial hyperreactivity. Smoking cessation resulted in a marked decrease in three biomarkers of cigarette smoke inhalation and improved asthma regulation, whereas smoking reduction had a less pronounced effect on biomarkers and only a small effect on asthma regulation.     

Urine cotinine as an index of smoking status in smokers during 96-hr abstinence: comparison between gas chromatography/mass spectrometry and immunoassay test strips.

Biomarkers such as carbon monoxide (CO) and cotinine (a nicotine metabolite) are used in tobacco cessation studies to assess smoking status. CO is easy to assess, is inexpensive, and provides immediate results. However, the short half-life of CO may limit its ability to identify smokers who have abstained for several hours. Quantitative methods (e.g., gas chromatography/mass spectrometry, or GC/MS) for measuring urine cotinine, which has a longer half-life, are valid and reliable, though costly and time consuming. Recently developed semiquantitative urine cotinine measurement techniques (i.e., urine immunoassay test strips, or ITS) address these disadvantages, though the value of ITS as a means of identifying abstaining smokers has not been evaluated. The present study examined ITS as a measure of smoking status in temporarily abstaining smokers. A total of 236 breath and urine samples were collected from smokers who participated in two separate studies involving three independent, 96-hr (i.e., Monday-Friday), Latin-square-ordered, abstinence or smoking conditions; a minimum 72-hr washout separated each condition. Each urine sample was analyzed with GC/MS and ITS. Under these study conditions, CO demonstrated moderate sensitivity (83.1%) and strong specificity (100%), whereas ITS assessment showed strong sensitivity (98.5%) and weak specificity (58.5%). In this study of short-term abstinence, ITS classified as nonabstinent nearly half of the samples collected from abstaining smokers. However, it classified nearly all nonabstinent smokers as currently smoking. Validation of ITS using GC/MS results from smokers undergoing more than 96 hr of abstinence may be valuable.