Determinants of salivary cotinine level: a population-based study in Brazil

OBJECTIVE: A cross-sectional population-based study was conducted to assess, in active smokers, the relationship of number of cigarettes smoked and other characteristics to salivary cotinine concentrations. METHODS: A random sample of active smokers aged 15 years or older was selected using a stepwise cluster sample strategy, in the year 2000 in Rio de Janeiro, Brazil. The study included 401 subjects. Salivary cotinine concentration was determined using gas chromatography with nitrogen-phosphorus detection. A standard questionnaire was used to collect demographic and smoking behavioral data. The relation between the number of cigarettes smoked in the last 24h and cotinine level was examined by means of a nonparametric fitting technique of robust locally weighted regression. RESULTS: Significantly (p<0.05) higher adjusted mean cotinine levels were found in subjects smoking their first cigarette within five minutes after waking up, and in those smoking 1-20 cigarettes in the last 24h who reported inhaling more than (1/2) the time. In those smoking 1-20 cigarettes, the slope was significantly higher for those subjects waiting for more than five minutes before smoking their first cigarette after waking up, and those smoking "light" cigarettes when compared with their counterparts. These heterogeneities became negligible and non-significant when subjects with cotinine >40 ng/mL per cigarette were excluded. CONCLUSIONS: There was found a positive association between self-reporting smoking five minutes after waking up, and inhaling more than (1/2) the time are consistent and higher cotinine levels. These can be markers of dependence and higher nicotine intake. Salivary cotinine proved to be a useful biomarker of recent smoking and can be used in epidemiological studies and smoking cessation programs.     

Measures of maternal tobacco exposure and infant birth weight at term

This study was undertaken to determine the relation between self-reported number of cigarettes smoked per day and urine cotinine concentration during pregnancy and to examine the relations between these two measures of tobacco exposure and birth weight. Data were obtained from the Smoking Cessation in Pregnancy project, conducted between 1987 and 1991. Cigarette smoking information and urine cotinine concentration were collected for 3,395 self-reported smokers who were receiving prenatal care at public clinics in three US states (Colorado, Maryland, and Missouri) and who delivered term infants. General linear models were used to quantify urine cotinine variability explained by the number of cigarettes smoked per day and to generate mean adjusted birth weights for women with different levels of tobacco exposure. Self-reported number of cigarettes smoked per day explained only 13.9% of the variability in urine cotinine concentration. Birth weight declined as tobacco exposure increased; however, the relation was not linear. The sharpest declines in birth weight occurred at low levels of exposure. Furthermore, urine cotinine concentration did not explain more variability in birth weight than did number of cigarettes smoked. These findings should be considered by researchers studying the effects of smoking reduction on birth outcomes.     

Saliva cotinine levels in smokers and nonsmokers

The authors collected by mail self-reported data on smoking habits and saliva samples that were analyzed for cotinine concentration in 222 smokers and 97 nonsmokers. Participants were members of the University of Geneva (Switzerland) in 1995. The 207 cigarette-only smokers smoked on average 10.7 cigarettes/day and had a median concentration of cotinine of 113 ng/ml. The cotinine concentration was moderately associated with the number of cigarettes smoked per day (+14 ng/ml per additional cigarette, p < 0.001, R2 = 0.45) and was 54 ng/ml higher in men than in women after adjustment for cigarettes per day and for the Fagerstr?m Test for Nicotine Dependence. The cotinine level was not associated with the nicotine yield of cigarettes (r= 0.08). In nonsmokers, the median concentration of cotinine was 2.4 ng/ml. The cotinine concentration was 1.5 times higher in nonsmokers whose close friends/spouses were smokers than in nonsmokers whose close friends/spouses were nonsmokers (p = 0.05). A cutoff of 7 ng/ml of cotinine distinguished smokers from nonsmokers with a sensitivity of 92.3% and a specificity of 89.7%; a cutoff of 13 ng/ml provided equally satisfactory results (sensitivity, 86.5%; specificity, 95.9%). This study provides evidence for the construct validity of both questionnaires and saliva cotinine for the assessment of active and passive exposure to tobacco smoke.     

Stages of change, smoking characteristics, and cotinine concentrations in smokers: setting priorities for smoking cessation

ObjectiveWe assessed whether the salivary cotinine content of daily smokers varied with the readiness to quit and smoking characteristics.MethodsThis cross-sectional study was conducted in Barcelona, Spain (n = 1245) in 2004–2005. We administered a questionnaire to assess smoking behaviour and collected saliva to determine the cotinine content. We determined the distribution of 278 adult daily smokers across different stages of change and categorised them by individual and smoking characteristics. We used medians and interquartile ranges (IQR) to relate cotinine concentrations to different stages of change, tobacco consumption, and nicotine dependence based on the Fagerström Test for Nicotine Dependence (FTND).ResultsAround 68%, 22%, and 11% of smokers were in precontemplation, contemplation, and preparation stages, respectively. A mean of 17.0 cigarettes was smoked daily, with no differences among stages of change. The median cotinine concentration was 151.3 ng/ml (IQR: 83.2–227.8 ng/ml), with no differences among stages of change. The cigarette consumption scores, FTND, and time to first cigarette of the day were positively associated with cotinine concentration.ConclusionsThe cotinine concentration was similar among the stages of change, but varied within each stage according to the number of cigarettes smoked, time to first cigarette of the day, and nicotine dependence.     

Questionnaire and hair measurement of exposure to tobacco smoke

To assess the relation between nicotine and cotinine levels in hair and reported exposure to environmental tobacco smoke (ETS), hair samples from 112 children (aged 3 months to 10 years) and 76 of their mothers were analyzed and information on the smoking habits of household adults in the preceding 6 months recorded. It was found that the levels of nicotine in children's hair were related to the number of smokers in the house, and increased with the total number of cigarettes smoked by all household adults (P<0.0001). In a multiple regression analysis, mother's smoking was much more a contributor to children's nicotine levels than smoking by the father or other household adults. Cotinine levels were less strongly associated with reported ETS exposure than nicotine. There was a strong correlation between nicotine hair levels in children and mothers (r(s)=0.7, P<0.0001). However, nicotine levels in the hair of active smokers were not correlated with the reported number of cigarettes they smoked per day. In this population, there was a consistent relation between exposure to ETS (assessed by questionnaire) and dose (as measured by nicotine in hair). We conclude that hair nicotine levels rather than hair cotinine levels provide an informative and objective measure of ETS exposure. The number of cigarettes smoked by active smokers may not be an accurate measure of the total nicotine levels in their bodies.     

Evidence for compensation in smokers of low yield cigarettes

To determine the relation of smoking low yield cigarettes (tar yield less than 15.0 mg and nicotine yield less than 1.0 mg per cigarette) to the number of cigarettes smoked per day, we analysed information provided on self-administered questionnaires by 7706 current, regular cigarette smokers. The mean age at starting to smoke and the mean number of years of smoking were not consistently different in smokers of low yield compared with smokers of high yield cigarettes. In contrast, at all ages in both men and women, smokers of low yield cigarettes smoked significantly more cigarettes per day than smokers of high yield cigarettes. The differences in the number of cigarettes smoked per day between smokers of low and high yield cigarettes were small--about 3 cigarettes per day in men and about 1 1/2 cigarettes per day in women. However, these small differences might translate to the smoking of as many as one billion more packs of cigarettes per year in the United States alone. The potential beneficial effect of the smoking of cigarettes whose yield per cigarette is lower must be weighed against a possible adverse effect of the smoking of more cigarettes if the relation between smoking low yield cigarettes and smoking more cigarettes is causal.     

Cross-sectional study on the relationship between body mass index and smoking, and longitudinal changes in body mass index in relation to change in smoking status: the Tromso Study

AIMS: To evaluate the effects of smoking and other lifestyle factors on body mass index (BMI), and changes in BMI in relation to changes in smoking status. METHODS: A cross-sectional study was performed on 10,920 males (3937 smokers) and 12,090 females (4343 smokers) who participated in the fourth Troms? Study (performed in 1994-95). A longitudinal study was performed on 2364 males (732 smokers in 1994-95) and 2738 females (942 smokers in 1994-95) who participated in both the fourth and the fifth Troms? studies (performed in 2001). RESULTS: In the cross-sectional study, current smokers of both genders had a lower BMI (25.0+/-3.4 vs. 25.5+/-3.2 kg/m(2) in males, and 23.9+/-3.9 vs. 25.3+/-4.6 kg/m( 2) in females, p<0.01), a lower degree of physical activity, and a higher consumption of coffee and alcohol than never-smokers. We found a U-shaped relationship between number of cigarettes smoked per day and BMI, with the lowest BMI in those smoking 6- 10 cigarettes per day. Heavy smokers and never-smokers had similar BMI. In the longitudinal study, continuing smokers had a smaller increase in BMI than those who gave up smoking. In those who gave up smoking, there was a significant, positive relationship between number of cigarettes smoked in 1994-95 and increase in BMI. CONCLUSIONS: There is a U-shaped relationship between number of cigarettes smoked per day and BMI. Smoking cessation is associated with an increase in weight as compared to those who continue smoking.     

Behavioral factors predicting serum cotinine concentrations of male smokers in a Japanese community.

Cigarette-derived toxic substances are inhaled along with the nicotine that is absorbed to satisfy the smoker's physical demand. Therefore, serum cotinine, a metabolite of nicotine, may be considered to be an indirect marker of absorption of the other toxic substances from smoking. However, few studies have examined factors related to serum cotinine concentrations in natural settings. The authors, therefore, have studied relations among patterns of smoking behavior and serum cotinine concentrations of community residents. Subjects were 60 smoking men living in the town of Yamasaki, Hyogo Prefecture, Japan. Number of daily cigarettes, depth of inhalation, hours from the last cigarette smoked and the total nicotine tolerance score were significantly, while neither nicotine-yields nor butt length of a discarded cigarette was correlated with serum cotinine concentrations. Multiple regression analysis confirmed that depth of inhalation and hours from the last cigarette smoked were independently significant. This finding suggests that attention only to self-reported daily number of cigarettes smoked may not be sufficient to detect smokers who are actually at high risk. Healthcare workers should also pay attention to smokers' patterns of smoking, particularly depth of inhalation.     

Spontaneous cigarette brand switching: consequences for nicotine and carbon monoxide exposure.

A group of smokers who had participated in smoking-related studies three to six years earlier were re-studied to assess changes in their smoking practices. Individuals who smoked the same brands of cigarettes showed no change in plasma cotinine (reflecting exposure to nicotine) or expired carbon monoxide (CO) concentration. Those who switched to cigarettes of lower nicotine yield (average decrease 38 per cent) showed reduced plasma cotinine concentrations, due primarily to smoking fewer cigarettes per day. The intake of nicotine per cigarette was not different. Subjects who smoked cigarettes of higher yield (102 per cent increase) had higher cotinine and CO levels, due to greater intake per cigarette.     

The Relationship Between Maternal–Fetal Attachment and Cigarette Smoking Over Pregnancy

Cigarette smoking during pregnancy is one of the most preventable causes of infant morbidity and mortality, yet 80 % of women who smoked prior to pregnancy continue to smoke during pregnancy. Past studies have found that lower maternal–fetal attachment predicts smoking status in pregnancy, yet past research has not examined whether maternal–fetal attachment predicts patterns or quantity of smoking among pregnant smokers. The aim of this study was to examine the relationship between maternal–fetal attachment and patterns of maternal smoking among pregnant smokers. We used self-reported and biochemical markers of cigarette smoking in order to better understand how maternal–fetal attachment relates to the degree of fetal exposure to nicotine. Fifty-eight pregnant smokers participated in the current study. Women completed the Maternal–Fetal Attachment Scale, reported weekly smoking behaviors throughout pregnancy using the Timeline Follow Back interview, and provided a saliva sample at 30 and 35 weeks gestation and 1 day postpartum to measure salivary cotinine concentrations. Lower maternal–fetal attachment scores were associated with higher salivary cotinine at 30 weeks gestation and 1 day postpartum. As well, women who reported lower fetal attachment reported smoking a greater maximum number of cigarettes per day, on average, over pregnancy. Lower maternal–fetal attachment is associated with greater smoking in pregnancy. Future research might explore whether successful smoking cessation programs improve maternal assessments of attachment to their infants.     

Active and passive exposure status to tobacco smoke of department store employees measured by cotinine ELISA

Quantitation of urinary cotinine, a major metabolite of nicotine, by an enzyme-linked immunosorbent assay (ELISA), was performed in parallel with questionnaires containing items on smoking status, such as active and/or passive smokers, the number of cigarettes smoked, and the presence or absence of active smokers in the surroundings in a department store (517 employees). The cotinine values corrected by creatinine (cotinine-creatinine ratios, CCRs) approximately conformed to the extent of self-recognition of their exposure status to tobacco-smoke, and were low in the order of active smokers, passive smokers and non-smokers who felt they were not exposed to tobacco-smoke. Occupational differences of the CCRs were not found in the employees. In the active smokers, the CCRs were increasing according to the number of cigarettes per day they smoked, and the values were nearly proportional to nicotine contents of cigarette in the moderate smokers who smoked 11-20 cigarettes per day. The CCRs of males were higher than those of females in the active smokers, which also agreed well with the numbers of cigarettes they smoked per day. In the passive smokers, the CCRs were remarkably and significantly higher in subjects who felt they were exposed to tobacco-smoke both in their workplaces and homes. Urinary CCRs measured by ELISA are thus found to be a reliable and excellent objective indicator of both active and passive exposure-status to tobacco-smoke.     

Smoking topography and biomarkers of exposure among Japanese smokers: associations with cigarette emissions obtained using machine smoking protocols

Objectives

Although the relative risk of lung cancer due to smoking is reported to be lower in Japan than in other countries, few studies have examined the characteristics of Japanese cigarettes or potential differences in smoking patterns among Japanese smokers.

Methods

To examine tar, nicotine and carbon monoxide (TNCO) emissions from ten leading cigarettes in Japan, machine smoking tests were conducted using the International Organization for Standardization (ISO) protocol and the Health Canada Intense (HCI) protocol. Smoking topography and tobacco-related biomarkers were collected from 101 Japanese smokers to examine measures of exposure.

Results

The findings indicate considerable variability in the smoking behavior of Japanese smokers. On average, puffing behaviors observed among smokers were more similar to the parameters of the HCI protocol, and brands with greater ventilation that yielded lower machine values using the ISO protocol were smoked more intensely than brands with lower levels of ventilation. The smokers of “ultra-low/low” nicotine-yield cigarettes smoked 2.7-fold more intensively than those of “medium/high” nicotine-yield cigarette smokers to achieve the same level of salivary cotinine (p = 0.024). CO levels in expiratory breath samples were associated with puff volume and self-reported smoking intensity, but not with nominal values of nicotine-yield reported on cigarette packages.

Conclusions

Japanese smokers engaged in “compensatory smoking” to achieve their desired nicotine intake, and levels of exposure were greater than those suggested by the nominal value of nicotine and tar yields reported on cigarette packages.     

Saliva cotinine and recent smoking--evidence for a nonlinear relationship.

Cotinine concentration in various body fluids is considered to be among the most useful markers of nicotine exposure currently available. Despite the prevailing consensus concerning cotinine''s usefulness, cotinine''s large intrasubject variability has led some to question the value of a single-point measurement. Several individual differences (for example, age, race, sex, and so forth) may affect cotinine excretion, and a peculiar nonlinearity between the number of cigarettes smoked and cotinine concentration has been reported previously in the literature. The purpose of this investigation was to examine the nature of the association between cotinine and reported number of cigarettes smoked after adjustment for the relationship between cotinine and age, a key individual difference known to affect drug absorption, distribution, metabolism, excretion, and tissue sensitivity. The authors examined the relationship between saliva cotinine and daily cigarette consumption in 116 smokers (mean age = 37.4 years; average number of cigarettes smoked daily = 20.1) who logged each cigarette into a hand-held computer as part of a study on the accuracy of recall. The Pearson correlation between saliva cotinine and the logged number of cigarettes smoked in the previous 17 hours (the time window corresponding to the half-life of cotinine) accounted for significantly more of the variance in cotinine than did the average logged number of cigarettes smoked daily during 5 days. Age was also significantly associated with cotinine levels. Further examination of the relationship between cotinine and amount smoked in the previous 17 hours revealed evidence for a significant nonlinear component.(ABSTRACT TRUNCATED AT 250 WORDS)     

Heterogeneity in Smokers' Responses to Tobacco Control Policies

This paper uses unconditional quantile regression to estimate whether smokers' responses to tobacco control policies change across the distribution of smoking levels. I measure smoking behavior with the number of cigarettes smoked per day and also with serum cotinine levels, a continuous biomarker of nicotine exposure, using individual‐level repeated cross‐section data from the National Health and Nutrition Examination Surveys. I find that the cigarette taxes lead to reductions in both the number of cigarettes smoked per day and in smokers' cotinine levels. These reductions are most pronounced in the middle quantiles of both distributions in terms of marginal effects, but most pronounced in the lower quantiles in terms of tax elasticities. I do not find that higher cigarette taxes lead to statistically significant changes in the amount of nicotine smokers ingest from each cigarette. Copyright © 2015 John Wiley & Sons, Ltd.     

Children's exposure to environmental tobacco smoke in the home: comparison of urine cotinine and parental reports

The authors examined the relationship between parent-reported estimates of children's exposure to environmental tobacco smoke (ETS) in the home and children's urinary cotinine levels. Data were collected from a largely ethnic minority, low-income, urban sample of households in which a child had asthma and at least 1 household member smoked. Information about level of household smoking restriction, parental smoking status, and number of cigarettes smoked per day accounted for approximately 45% of the variance in cotinine concentration. Detailed information about the duration of household smoking or children's ETS exposure added no additional significant information. Questionnaires eliciting detailed information about smoking habits and children's ETS exposure may be no better at predicting children's urinary cotinine levels than simpler surveys that inquire about smoking restrictions in the home, parental smoking status, and number of cigarettes smoked at home per day.     

Children's Exposure to Environmental Tobacco Smoke in the Home: Comparison of Urine Cotinine and Parental Reports

The authors examined the relationship between parent-reported estimates of children's exposure to environmental tobacco smoke (ETS) in the home and children's urinary cotinine levels. Data were collected from a largely ethnic minority, low-income, urban sample of households in which a child had asthma and at least 1 household member smoked. Information about level of household smoking restriction, parental smoking status, and number of cigarettes smoked per day accounted for approximately 45% of the variance in cotinine concentration. Detailed information about the duration of household smoking or children's ETS exposure added no additional significant information. Questionnaires eliciting detailed information about smoking habits and children's ETS exposure may be no better at predicting children's urinary cotinine levels than simpler surveys that inquire about smoking restrictions in the home, parental smoking status, and number of cigarettes smoked at home per day.     

The effect of paternal smoking on the birthweight of newborns whose mothers did not smoke. Group Health Medical Associates.

We examined the relationship of paternal smoking habits to birthweight in a cohort of infants enrolled at birth (n = 1219). To assess validity of parental smoking reports, cord serum levels of cotinine were measured in 175 newborns. A mean birthweight deficit of 88 g was found in newborns of nonsmoking mothers whose fathers smoked more than 20 cigarettes/day. Only 2 of 138 newborns whose mothers said they were nonsmokers had cotinine levels indicating that their mothers were active smokers. Among infants of nonsmoking mothers, detectability of cotinine in cord blood was significantly correlated with the number of cigarettes smoked daily by fathers. These data suggest that fetal growth may be adversely affected when the mother is passively exposed to tobacco smoke during pregnancy.     

Properties of saliva cotinine in young adult light smokers

The half-life of saliva cotinine and its accuracy at detecting light or intermittent smoking were examined. Five subjects provided daily saliva samples for 23 days and quit smoking on day 4. An average of 2.8 days was required for saliva continue to drop below the cutoff for classification as a smoker. All smokers smoked intermittently at various times after day 9. In most cases the smoking of one or two cigarettes was detected in the saliva sample on subsequent days. Saliva cotinine was sensitive to low rates of smoking and to intermittent smoking.     

Apparent underreporting of cigarette consumption among Mexican American smokers.

To determine the accuracy of self-report of cigarette consumption among Mexican American smokers, we compared self-reported cigarette use and serum cotinine concentrations in a sample of 547 participants in the Hispanic Health and Nutrition Examination Survey (HHANES). We defined underreporting of cigarette use as a cotinine to cigarette-per-day ratio of greater than 0.142 microM/l which represented a substantial discrepancy between self-reported consumption and serum cotinine. Of the 98 men and 97 women who reported smoking one to nine cigarettes/day, 20.4 percent and 24.7 percent, respectively, underreported their cigarette consumption. Underreporting was less common among men and women smoking 10 to 19 cigarettes/day (8.3 percent and 10.8 percent, respectively) and 20 or more cigarettes/day (2.2 percent and 2.9 percent, respectively). Comparison of underreporters to other smokers by demographic characteristics within sex and cigarettes/day categories showed no differences. Differences in cotinine metabolism and extremely efficient smoking are alternative explanations that can not be ruled out with these data. We believe, however, that a proportion of Mexican American light smokers may underreport the quantity of cigarettes smoked per day, and may truly be moderate or heavy smokers.     

Smoking habits and risk of fatal stroke: 18 years follow up of the Oslo Study.

STUDY OBJECTIVE: To examine the risk of fatal stroke in relation to smoking habits in men screened for the Oslo study. DESIGN: The Oslo study is a prospective, cohort study of the epidemiology and preventive aspects of cardiovascular diseases in middle aged men. Screening started in May 1972 and results after 18 years of follow up are reported. PARTICIPANTS: There were 16209 men aged 40-49 years, of whom 16173 had no stroke history. Eighty five men died from stroke, of whom 48 were daily cigarettes smokers, 7 were pipe and cigar smokers, 15 smoked cigarettes and pipe or cigars daily, 11 were previous cigarette smokers, and 4 had never smoked cigarettes. MAIN RESULTS: Results of proportional hazards regression analysis adjusted for age, diastolic blood pressure, and glucose concentration showed the following rate ratios (RR) (95% confidence interval) of smoking groups compared with those who had never smoked or had previously smoked: combined cigarette and cigar or pipe smokers, RR = 6.1 (3.0, 12.5); cigarettes only, RR = 4.1 (2.3,7.4); and pipe and/or cigars only RR = 2.2 (0.9,5.5). The overall, age adjusted risk of smoking cigarettes daily was 3.5 and was found to increase with increasing cigarette consumption. Regardless of their smoking group, stroke cases had increased diastolic (DBP) and systolic blood pressure (SBP) when compared with men who had not had a stroke. The absolute differences in DBP and SBP between stroke cases and others for never and previous cigarette smokers versus daily smokers were twice as large: DBP, 12.1 mmHg versus 6.5 mmHg respectively and SBP, 16.0 mmHg versus 7.1 mmHg respectively. A high BMI increased the risk of fatal stroke of never and previous cigarette smokers. Men being treated for hypertension at the time of screening had three times the crude risk of fatal stroke of men who were not taking hypertensive treatment. CONCLUSIONS: Daily cigarette smoking increased the risk of fatal stroke three and a half times. Combined cigarette and pipe or cigar smoking had a higher risk than smoking cigarettes only. An increased risk was found in relation to increased daily cigarette consumption.