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.     

The effectiveness of a nurse-managed perinatal smoking cessation program implemented in a rural county.

The present study (a) examined the effectiveness of a nurse-managed smoking cessation program, that was totally integrated into routine perinatal care, on the cessation rates of pregnant smokers in a rural community, and (b) assessed the subject characteristics associated with smoking cessation success. Data were collected from a convenience sample of 194 pregnant women who stated that they were smokers at the onset of their pregnancies. The study compared the effects of usual care (n = 93) versus the Smoke Free Baby & Me program (n = 101), which included the American Cancer Society's Make Yours a Fresh Start Family program. Smoking status was measured by self-report and urinary cotinine at four points during pregnancy and postpartum. At the postpartum visit, more women in the experimental group reported that they were not smoking compared with those in the control group (37.3% vs. 16.7%), Pearson's chi2 (n = 87) = 4.37, p = .037, and they had higher validated (urinary cotinine <200 ng/ml) smoking cessation rates (n = 80, t = 2.449, p = .017) if they had quit smoking by the first prenatal visit. Smoking cessation was positively associated with level of education and negatively associated with gravidity, parity, the number of smokers in the household, and the number of cigarettes smoked per day at the first prenatal visit. Significant discordance was found between self-report and urinary cotinine assays at all prevalence points, regardless of group. In conclusion, this nurse-delivered program integrated into perinatal care influenced the smoking behaviors of "recent quitters" but had no effect on those who reported smoking at the first prenatal visit. Implications for clinical practice are discussed.     

Accuracy of parental reporting of secondhand smoke exposure: The National Health and Nutrition Examination Survey III.

The accuracy of parental reports of youth secondhand smoke exposure has received limited attention in the research literature. Such reports were compared to serum cotinine levels among participants of the National Health and Nutrition Examination Survey III who were aged 4-16 years. Likely smokers with serum cotinine values of 14 ng/ml or more and self-reported tobacco users were excluded from the analysis (n = 87), leaving 2,524 youth participants. One adult guardian, typically the parent, was asked to identify household smokers and estimate the number of cigarettes smoked in the home. Using cotinine levels of at least 0.2 ng/ml as the criterion, we found the sensitivity and specificity of any reported smokers in the home to be .65 and .92, respectively. Spearman correlations between cotinine levels and the number of smokers and the number of cigarettes consumed in the household were .67 and .68, respectively, and varied little across subgroups, including age, gender, and ethnicity of the child as well as household poverty status and educational attainment of the parent. Parental reports of household smoking alone fail to capture all youth secondhand smoke exposures, but they correlate well with cotinine levels when expressed as the number of household smokers or the number of cigarettes smoked in the household. Additional research is needed to determine whether reliance on parental reports of secondhand smoke exposure leads to bias in studies examining health outcomes in children and adolescents. Also, additional research is needed to better determine the level of secondhand smoke exposure that is biologically important in children and adolescents.     

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.     

Validity of self-reported smoking status: Comparison of patients admitted to hospital with acute coronary syndrome and the general population

Many studies rely on self-reported smoking status. We hypothesized that patients with acute coronary syndrome (ACS), a smoking-related condition, would be more prone to misclassify themselves as ex-smokers, because of pressure to quit. We compared patients admitted with ACS with a general population survey conducted in the same country at a similar time. We determined whether ACS patients who classified themselves as ex-smokers (n = 635) were more likely to have cotinine levels suggestive of smoking deception than self-reported ex-smokers in the general population (n = 289). On univariate analysis, the percentage of smoking deceivers was similar among ACS patients and the general population (11% vs. 12%, p = .530). Following adjustment for age, sex and exposure to environmental tobacco smoke, ACS patients were significantly more likely to misclassify themselves (adjusted OR = 14.06, 95% CI 2.13-93.01, p = .006). There was an interaction with age whereby the probability of misclassification fell significantly with increasing age in the ACS group (adjusted OR = 0.95, 95% CI 0.93-0.97, p<.001), but not in the general population. Overall, smoking deception was more common among ACS patients than the general population. Studies comparing patients with cardiovascular disease and healthy individuals risk introducing bias if they rely solely on self-reported smoking status. Biochemical confirmation should be undertaken in such studies.     

Comparison of two self-help smoking cessation booklets

OBJECTIVE: To compare two self-help smoking cessation booklets distributed to callers to a Quitline telephone service in Queensland (Australia). DESIGN: Callers were randomised to receive either a structured 14-day quit programme (Time to quit) or another booklet and described four broad stages of quitting (Can quit). Approximately one month later, these callers were interviewed by telephone. MAIN OUTCOME MEASURES: Self-reported smoking status at one month and recent quit attempts together with process measures. RESULTS: Altogether, 521 callers (78.3%) were interviewed. They were heavier smokers when compared with all Queensland smokers: on average they had smoked for more than 15 years, smoked nearly 25 cigarettes per day, and almost two-thirds had attempted to quit smoking in the past year. In each group, significant proportions either did not begin to use the booklet (50.5-56.0%), or did not complete its use (77.4-82.3%). There were no differences in the self-reported quit rates at one month (17.0% vs 16.1%; p = 0.93). In an ordinal regression modelling procedure involving age, sex, number of recent quit attempts, number of cigarettes smoked per day, smoking status of partner, number of five closest friends who smoke, education, and booklet received, only the number of cigarettes smoked per day was significantly related to smoking status at one month. CONCLUSIONS: Callers to telephone Quit-line services are typically heavier smokers than the general smoking population, and simple strategies, such as self-help booklets, appear to achieve relatively high success. Nevertheless, there is potential to improve the effectiveness of these materials by making a range of materials available and encouraging callers to make a serious attempt to quit smoking.     

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.     

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.     

A pilot study of smoking and associated behaviors of low-income expectant fathers.

Pregnancy is considered a teachable moment for helping women who smoke to quit, yet few studies have examined smoking behavior of expectant fathers. The present study considers the possibility that pregnancy is a teachable moment for expectant fathers as well and describes smoking and associated behaviors of men during their partner's pregnancy. Participants were 138 low-income men living with their pregnant partners. Using telephone interviews, we found 63% of the men had smoked at least 100 cigarettes in their lifetime. Current smoking was reported by 49.3% of expectant fathers (39.1% daily smoking; 10.2% some days). Expectant fathers' current smoking was associated with having a lower level of education (p<.0001), pregnant partner being a current smoker (p=.0002), higher quantity of alcohol consumption per day of drinking (p=.0003), and absence of smoking prohibitions inside the home (p<.0001). In the past year, 70.1% of the current smokers tried to quit. We found high rates of smoking in low-income expectant fathers, and an expectant father's smoking during his partner's pregnancy was associated with his pregnant partner continuing to smoke. A majority of expectant fathers identified as current smokers tried to quit in the past year or indicated an intention to quit in the near future. Intervention during pregnancy that targets pregnant women and expectant fathers who smoke could lead to more households without tobacco use and thus have positive implications for paternal, maternal, and family health. Further clinical and research attention is needed to address the smoking behaviors of both expectant fathers and their pregnant partners.     

Gender effects of reported in utero tobacco exposure on smoking initiation, progression and nicotine dependence in adult offspring.

We examined the relationship between self-reported in utero tobacco exposure and gender on smoking initiation, progression of cigarette use (i.e., telescoping), and current levels of nicotine dependence in adult treatment-seeking smokers. Subjects (N = 298) who reported "yes" (28% of the original sample) or "no" (50% of the original sample) to in utero tobacco exposure were included in the analyses. Telescoping was calculated as the difference between the age respondents smoked their "first full cigarette" and the age when they started smoking daily. Females who reported being exposed in utero transitioned from initial to daily cigarette use more rapidly than females not exposed. The opposite effect was found for males, which may be related to our finding that in utero exposure lowered the age of cigarette experimentation in exposed compared with unexposed males. Measures of current cigarette use and dependence (i.e., Fagerstr?m Test for Nicotine Dependence, prior withdrawal, number of past year quit attempts) were significantly associated with reported in utero exposure, gender, or interactions of exposure and gender. In utero tobacco exposure may accelerate the progression from experimentation to daily use in girls, result in early tobacco experimentation among boys, and produce higher levels of nicotine dependence among adult smokers.     

Cigarette smoking weakens exercise habits in healthy men.

To investigate the longitudinal impact of smoking cessation and relapse on the exercise habits of apparently healthy Japanese men, 750 subjects presenting for a checkup at a metropolitan health center were surveyed annually for 7 years. Exercise was dichotomously classified as none or any. Subjects were grouped in two categories: 98 smokers who ceased smoking during the second year of the study, matched with 196 continuing smokers and 196 men who had never smoked; and 52 relapsed smokers (including 2 new smokers) who did not smoke at baseline or at Year 1 but smoked from Year 2 to final follow-up, matched with 104 continuing smokers and 104 never-smokers. Based on self-reported responses to questionnaires, exercise was consistently less prevalent among smokers who did not quit than among never-smokers throughout the study. Habitual exercise in subjects who had quit smoking increased during the follow-up (any exercise: 42.9% at baseline increased to 51% at final follow-up, p for longitudinal trend = .115). Habitual exercise in matched never-smokers did not change during the study and decreased significantly among persistent smokers (p = .025). Habitual exercise in relapsed smokers decreased during the follow-up (any exercise: 50.0% at baseline declined to 32.7% at final follow-up, p = .007), but habitual exercise in matched persistent smokers and never-smokers did not change. We conclude that smoking and sedentary lifestyle coexist continuously, that smoking cessation is associated with increased habitual exercise among healthy men, and that relapse is associated with reduced habitual exercise, suggesting that cigarette smoking weakens exercise habits.     

The relationship of smoking cessation to sociodemographic characteristics, smoking intensity, and tobacco control policies.

The present study examined the relationship between recent smoking cessation activities and sociodemographic characteristics, smoking intensity, and tobacco control policies among daily smokers in the United States. The study used the U.S. Current Population Survey 1998-1999 Tobacco Use Supplement, supplemented with information on state-level tobacco control policies. The sample was limited to individuals aged 25 years or older who were smoking daily 1 year ago. We estimated frequencies and multivariate logistic equations for making a quit attempt and remaining abstinent at least 3 months. These measures were related to demographic characteristics, smoking intensity, and tobacco control policies. Younger, higher socioeconomic status (SES), and less intense (fewer cigarettes per day) daily smokers were more likely to make quit attempts, but the likelihood of remaining abstinent for those making a quit attempt was greater for older, higher SES, and heavy daily smokers. We found evidence that cessation behaviors were related to higher cigarette prices and the presence of state-level media/comprehensive campaigns, but less clear evidence exists for an association with bans restricting workplace smoking. The results indicate that certain types of smokers are more likely to attempt to quit and to have success and that the characteristics of these smokers differ. Price policies can have an important role in helping daily smokers to quit. Further research is needed regarding the role of quantity smoked.     

Occult maternal exposure to environmental tobacco smoke exposure

Background

Environmental tobacco smoke (ETS) is a recognised air pollutant. Its harmful effects have been found to be implicated in health disorders, including unfavourable pregnancy outcomes. The discrepancy between self‐reported emvironmental tobacco smoke exposure and cotinine levels in pregnant non‐smokers in France was examined.

Method

Plasma cotinine was determined by a CPG‐SM method on women who had answered a self‐questionnaire describing their habits and environment during pregnancy.

Results

Of 698 pregnant women reported as non‐smokers, 305 (43.7%) claimed not to be exposed to ETS, yet 196 of these (64.3%) had plasma cotinine levels above the limit of detection.

Conclusion

Self‐reported data on ETS exposure in pregnant women therefore underestimate actual exposure. However, cotinine assay cab rectify this misclassification. An accurate identification of this risk factore will help to change attitudes towards ETS and avert its adverse effects on mother and fetus.Although environmental tobacco smoke (ETS) has not yet been monitored in France, it is probably, as in the United States National Health and Nutrition Examination Survey (1999–2002), a major source of indoor air pollution. Low levels of ETS exposure can result in unfavourable pregnancy outcomes,^1,2 and many pregnant women still believe that not smoking is sufficient to protect their fetus from ETS. Moreover, far less attention has been paid to perinatal ETS exposure. A better appraisal of these non‐maternal sources and measurement of corresponding prenatal exposure will provide a useful basis for further work and discussion on its effects.     

Smoking reduction in the Lung Health Study.

We examined the ability of smokers who failed to quit smoking in the Lung Health Study to reduce the number of cigarettes per day and maintain this reduction and whether reduction predicted increased or decreased future cessation. In the Lung Health Study, among smokers with early lung disease who wished to stop smoking, 3923 were randomized to a special intervention of counseling and nicotine gum for smoking cessation and to bronchodilator therapy or placebo. Among the 1722 who were still smoking at the first year follow-up, 27% smoked the same, 43% smoked 1%-49% fewer, and 30% smoked at least 50% fewer cigarettes per day. Reduction in cigarettes per day was accompanied by reduction in expired-air carbon monoxide. About half of the less-than-50% reducers and one-fifth of the at-least-50% reducers maintained or exceeded this reduction over the next 4 years. Reduction was associated with nicotine gum use. Greater reduction at year 1 predicted more quit attempts in year 2 but not more point prevalence abstinence at year 2 nor more quits or abstinence between years 2 and 5. We conclude that reduction can be maintained but such reduction neither predicts an increased nor decreased probability of future cessation.     

Association of post-treatment smoking change with future smoking and cessation efforts among adolescents with psychiatric comorbidity.

Little is known about how initial change following a smoking intervention relates to longer-term smoking outcomes among adolescent smokers with psychiatric comorbidity. The present study investigated this relationship among psychiatrically hospitalized adolescents (N = 183) who participated in a controlled trial comparing motivational interviewing to brief advice. Quit attempters (n = 37), reducers (n = 45), and maintainers (n = 101) were assembled based on, respectively, having made a quit attempt, having reduced smoking by at least 50%, and having reduced smoking by less than 50% in the first week after hospital discharge. Hierarchical linear models and generalized estimating equations were conducted to test group differences in average number of cigarettes per smoking day and odds of making a quit attempt during subsequent weeks of a 12-month continuous follow-up, and in cotinine-verified abstinence rates at 1, 6, and 12 months posthospitalization. Baseline smoking levels and presence of a substance use disorder or anxiety disorder were predictive of outcomes. After controlling for covariates, we found that quit attempters smoked less during follow-up than did the other change groups and that reducers smoked less than maintainers. Quit attempters evidenced a higher percentage of quit attempts during follow-up than did the other change groups. Reducers had a greater average percentage of quit attempts during follow-up than did maintainers. However, groups did not differ on cotinine-verified abstinence rates across the follow-up period. Findings have implications for initial post-treatment change as it relates to subsequent smoking and cessation outcomes among adolescent smokers at especially high risk for smoking persistence.     

Characteristics associated with self-identification as a regular smoker and desire to quit among college students who smoke cigarettes.

Tobacco use among college students increased substantially during the 1990s. Better understanding of college smokers is warranted to develop interventions specific to the needs of this population. We examined sociodemographic and tobacco-use characteristics associated with self-identification as a regular smoker and intentions to quit smoking among college students who smoke cigarettes. We conducted logistic regression analysis on baseline survey data from the Campus Health Action on Tobacco study, a 4-year group-randomized trial at 30 four-year colleges in Washington, Oregon, and Idaho. Students who self-identified as a regular smoker smoked more cigarettes before starting college, smoked a greater number of cigarettes the prior 30 days, smoked more cigarettes per day, and were more likely to smoke within 30 min of waking up, compared with students who were current smokers but did not consider themselves regular smokers. Females, older students, and those who had decreased the amount they smoked since coming to college were more likely to want to quit "very much." Females and students in early college years were more likely to be planning to quit before graduation, as were students who had decreased the amount they smoked since coming to college. Interventions should target students who are in their early college years, given that habits prior to college, changes in smoking habits while in college, and year in college are associated with students' self-identification as a regular smoker, desire to quit smoking, or plan to quit smoking while in college.     

Prevalence of smoking and its relationship with carotid atherosclerosis in Alaskan Eskimos of the Norton Sound region: the GOCADAN study.

Since 2000, the Genetics of Coronary Artery Disease in Alaska Natives (GOCADAN) study has been collecting information on cardiovascular disease (CVD) and its risk factors from 1,214 Alaska Natives of the Norton Sound region, a population with increasing rates of heart disease and stroke. Because smoking was reported in a large proportion of the participants, this analysis was undertaken to evaluate smoking patterns and their relation to other risk factors and to CVD. The relationships among smoking habits and demographic factors, body mass index, plasma fibrinogen, prevalent hypertension, and carotid plaque were evaluated. Eighty percent of participants had smoked 100+ cigarettes in their lifetime. Fifty-seven percent of women and 63% of men (p = .12) were current smokers: one in four smokers had quit. Current smokers (OR = 2.1; 95% CI = 1.1-3.8) and those who had quit <5 years ago (OR = 1.6; 95% CI = 1.1-2.2) were more likely than non-smokers to have carotid plaque. Pack-years smoked also were correlated with carotid plaque. The high prevalence of smoking and low rates of cessation in this population demonstrate an urgent need for smoking prevention and cessation programs among Alaskan Eskimos of the Norton Sound region and other Alaska Native groups.     

Tobacco use and readiness to quit smoking in low-income HIV-infected persons.

The study aim was to identify covariates of smoking status and readiness to quit that encompassed key sociodemographic and health status variables, health-related quality of life, drug use and unprotected sex, and tobacco use variables in a cohort of low-income persons living with HIV. We also examined the impact of HIV diagnosis on smoking cessation. The sample (N = 428) was mostly male (59%) and Black (53%) or Hispanic (30%), and had a high school education or less (87%). Mean age was 40 years. Two-thirds of participants were current smokers, 19% former smokers, and 16% never smokers. Current smokers smoked a mean of 16 cigarettes/day for 22 years; 42% were in the precontemplation stage of readiness to quit smoking, 40% were contemplators, and 18% were in preparation. Most current smokers (81%) reported receiving medical advice to quit smoking. Multivariate logistic regression analyses indicated that current smokers, compared with former smokers, were more likely to use illicit drugs, perceive a lower health risk for continued smoking, and report less pain. Current smokers, compared with nonsmokers (former and never smokers), were more likely to report greater illicit drug use in their lifetime, current illicit drug use, and less pain. A multiple linear regression indicated that greater current illicit drug use, greater emotional distress, and a lower number of quit attempts were associated with lower stage of readiness to quit smoking. These findings confirm a high prevalence of smoking among HIV-infected persons and suggest a complex interplay among drug use, pain, and emotional distress that impact smoking status and, among smokers, readiness to quit. Tobacco control programs for HIV-infected persons should build motivation to quit smoking and address salient barriers to cessation--such as comorbid drug use, emotional distress, pain, and access to and coverage for treatment--and should educate smokers regarding the HIV-specific health benefits of cessation.     

Smoking cessation by socioeconomic status and marital status: the contribution of smoking behavior and family background.

We studied socioeconomic status and marital status as predictors of smoking cessation, adjusting for previous smoking behavior and family background by using a large Finnish prospective twin dataset unselected for smoking behavior. The data were collected by postal surveys in 1981 and 1990, and the sample comprised 3,069 current smokers, of whom 20% had quit smoking by 1990. Logistic regression analyses of all twin individuals and conditional logistic regression analysis of discordant pairs were used to predict smoking cessation. High education predicted smoking cessation among both men (OR=2.32, 95% CI=1.31-4.10) and women (OR=3.98, 95% CI=1.85-8.51) as did high social class among women. Additionally, starting at a late age, smoking a small number of cigarettes per day, and a low level of nicotine per cigarette predicted cessation. Socioeconomic differences in cessation diminished only slightly when we adjusted for smoking behavior factors. Among the twin pairs who were discordant in terms of smoking cessation, the twin who continued smoking also smoked more on average at baseline (men: OR=.94, 95% CI=.89-.99; women: OR=.82, 95% CI=.71-.94). The male twins who continued smoking had a smaller probability of getting married during the follow-up than had the cotwin who had quit smoking (OR=3.91, 95% CI=1.02-15.02). Indicators of socioeconomic status were important predictors of smoking cessation even when we adjusted for previous smoking behavior. For men, marriage was associated with an increased probability of cessation