Dependency, social factors, and the smoking cessation process: the doctors helping smokers study

We analyzed data obtained from a representative sample of the smoking patients (n = 1,338) of 66 family physicians to determine predictors of attempts to stop smoking, desire to quit smoking, and successful smoking cessation. Compared to subjects who made no attempt to quit smoking, subjects who tried to quit smoking tended to be younger, had tried to quit smoking in the year prior to the study, waited longer before smoking their first cigarette of the day, had more desire to quit smoking, and had more social support for quitting. Education and cigarettes smoked per day were not independently related to the subject making a quit attempt. Desire to quit smoking was associated with an attempt to quit in the year prior to the study and social support for smoking cessation (support of spouse, second most important social contact, and physician). Desire to quit smoking was not independently related to age, education, or dependency on cigarettes (measured by the number of cigarettes smoked per day and the length of time a subject waited before smoking the first cigarette of the day). Compared to subjects who tried to quit and failed, subjects who succeeded were older, smoked fewer cigarettes per day, and waited longer to smoke their first cigarette of the day. Spouse support, support of the second most important social contact, and advice of a doctor to quit smoking were not independently related to whether or not a cessation attempt would be successful. These data suggest that successful smoking cessation requires two components: social support to make an attempt to quit and the ability to overcome dependency on cigarettes to make the attempt successful.     

Does switching from cigarettes to pipes or cigars reduce tobacco smoke exposure?

Cigarette smoking histories, reported depth of inhalation, number of pipe and cigars (PC) smoked, serum thiocyanate (SCN) and expired air carbon monoxide (CO) levels were examined in PC male smokers enrolled in the Multiple Risk Factor Intervention Trial (MRFIT). Serum SCN levels for all PC smokers were higher than for non-smokers and lower than for current cigarette smokers. Levels were related to the amount of product smoke. Prior cigarette smokers had higher SCN levels when compared to PC users who had never smoked cigarettes, smoked a larger number of tobacco products per day, and reported inhaling into the chest more often. Prospective data on baseline cigarette smokers demonstrated that smokers who stopped all tobacco products had a greater drop in SCN and CO than those who switched to PC. The findings strongly suggest that cessation of all tobacco products is the best strategy for decreasing exposure to tobacco smoke.     

Indirect measures of cigarette use: expired-air carbon monoxide versus plasma thiocyanate

Indirect, biochemical measures of cigarette use are valuable in confirming smoking status in both cross-sectional and cessation studies. This study compares two such biochemical markers, expired-air carbon monoxide (CO) and plasma thiocyanate (SCN), in a representative population sample of 2,237 adults (ages 18–74) from the baseline survey of the Stanford Five City Project. CO and SCN are both significantly higher in self-reported smokers than in nonsmokers and correlate well with number of cigarettes smoked per day. CO appears to be more sensitive and specific than SCN in comparison to self-report, and CO misclassifies a significantly smaller number of nonsmokers, regular smokers, and light smokers (<9 cigarettes per day) than does SCN. Together, CO and SCN better classify smokers and nonsmokers than do either alone. Neither biochemical is a reliable indicator in irregular smokers (no cigarettes in past 48 hr). Despite its much shorter metabolic halflife, CO is a better indicator of cigarette use than is SCN in this cross-sectional study. CO is generally simpler and less expensive to measure than is SCN, and CO may be a preferable indirect measure of smoking status in some studies of smoking cessation.     

Gender differences in predictors for long-term smoking cessation following physician advice and nicotine replacement therapy.

We evaluated gender differences in demographic, smoking history, nicotine dependence, transtheoretical, and perceived stress variables as predictors of smoking cessation. Participants (n = 381) smoked at least 15 cigarettes per day and were motivated to quit. The outcome variable was 7-day abstinence at 1-year follow-up. Predictor variables included: age, education level, number of years smoking, cigarettes per day, quit attempts, nicotine dependence, stage of change, decisional balance, processes of change, self-efficacy, and perceived stress. Logistic regression analysis was used to derive predictive models for women and men. In women, lower scores for pre- and mid-treatment perceived stress significantly increased the likelihood of being abstinent at follow-up. For men, a higher level of education or number of quit attempts lasting > 24 hours in the past year, along with less frequent use of behavioural processes of change at baseline increased the probability of being abstinent at follow-up.     

Breastfeeding duration and perinatal cigarette smoking in a population-based cohort

OBJECTIVES: We examined the association between breastfeeding duration and maternal smoking before, during, and after pregnancy. METHODS: Data from the 2000-2001 Oregon Pregnancy Risk Assessment Monitoring System were used. Early weaning was defined as not breastfeeding at 10 weeks postpartum. RESULTS: At 10 weeks after pregnancy, 25.7% of mothers who initiated breastfeeding no longer breastfed. After controlling for confounders, quitters (mothers who quit smoking during pregnancy and maintained quit status after pregnancy) and postpartum relapsers (mothers who quit smoking during pregnancy and resumed smoking after delivery) did not have significantly higher risk for early weaning than nonsmokers. However, persistent smokers (mothers who smoked before, during, and after pregnancy) were 2.18 times more likely not to breastfeed at 10 weeks (95% confidence interval=1.52, 2.97). Women who smoked 10 or more cigarettes per day postpartum (i.e., heavy postpartum relapsers and heavy persistent smokers) were 2.3-2.4 times more likely to wean their infants before 10 weeks than were nonsmokers. CONCLUSIONS: Maternal smoking is associated with early weaning. Stopping smoking during pregnancy and decreasing the number of cigarettes smoked postpartum may increase breastfeeding duration.     

The use of nicotine patches with minimal intervention

BACKGROUND: This paper describes a natural, prospective, open-label study designed to evaluate the impact of free nicotine patches with minimal support for smoking cessation. METHODS: Surveys were administered to 223 participants who received nicotine patches from the American Lung Association. All participants received a 6-week supply of 15-mg/16-h transdermal nicotine patches, a self-help book Freedom from Smoking, and information about area smoking cessation classes. Follow-up telephone surveys were administered 6 weeks after the patches were distributed. Abstinence was measured through self-report exclusively. RESULTS: The overall quit rate at 6-weeks was 21% (47/223). Among nonquitters, the mean number of cigarettes smoked per day dropped from 25 at baseline to 14 at 6 weeks. There was a significant difference in the average number of patches used by quitters and nonquitters (26 versus 11, P < 0.001). CONCLUSIONS: Nicotine patches with minimal support can be effective in smoking cessation and smoking reduction. The availability of patches may have motivated participants to quit. Efforts to increase access to and use of nicotine patches may result in increased attempts to quit and successful quitting.     

The relationship between stages and biochemical markers of smoking. Workplace-based cross-sectional and longitudinal studies

In order to clarify smokers' characteristics by "Stages of Change" based on Prochaska's transtheoretical model, we conducted cross-sectional and logitudinal studies with biochemical markers of smoking and smoking habits. In a workplace-based sample of 277 male smokers, we examined cross-sectionally the relationships between stages and biochemical markers of smoking which include expired carbon monoxide concentrations and urinary nicotine metabolite concentrations, and smoking habits which include the number of cigarettes smoked per day, yields of cigarettes, inhalation patterns, time to first morning cigarette, and quit attempts in the past. Additionally we examined longitudinally the relationship between stages and expired carbon monoxide concentrations, the number of cigarettes, and yields of cigarettes. In the cross-sectional study there were significant differences among stages on expired carbon monoxide concentrations (P = 0.006), urinary nicotine metabolite concentrations (P = 0.049), the number of cigarettes smoked per day (P = 0.001), and yields of cigarettes (P = 0.042) using analyses of variance. There were also significant differences among stages on time to first morning cigarette (P = 0.018) and quit attempts in the past (P < 0.001) using chi-square tests. In the longitudinal study for each level of elevation in stage during a one-year period, expired carbon monoxide concentrations decreased on an average of 2.3 ppm (P = 0.125) and the number of cigarettes smoked per day decreased on an average of 2.8 cigarettes per day (P = 0.07). However, the yields of cigarettes did not change during the one-year period.     

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.     

Consumption of 'low-yield' cigarettes: its frequency and relationship to serum thiocyanate.

To determine the use and possible health risks of low-yield cigarettes, we ascertained the cigarette brands and serum thiocyanate (SCN) levels of 2,561 adult smokers (age 25-74) in population-based samples of seven upper Midwestern communities during 1980-82. Brands were coded according to December 1981 Federal Trade Commission (FTC) ratings for "tar", nicotine, and carbon monoxide (CO). Compared to 1980 data from the National Center for Health Statistics for the United States as a whole, a greater proportion of smokers in these communities smoked low-yield brands. More people with higher education than lesser and more women than men smoked low-yield cigarettes. Greater proportions of older people (65-75 years) than younger people (less than 65 years) smoked cigarettes in the highest and lowest brand yield categories. SCN, adjusted for number of cigarettes smoked and for sex, was only weakly associated with brand ratings for "tar" (r = +.12), nicotine (R = +.11), and CO (r = +.15). Furthermore, the gradient in SCN between lowest and highest quintiles of brand strength was less than 16 per cent--much lower than the 300-500 per cent gradient in smoke components implied by FTC ratings. These data add to the evidence that smoking low-yield cigarettes may not be significantly less hazardous than smoking high-yield brands.     

Demographics and cigarette smoking among women

BACKGROUND. A population-based sample of 893 white women ages 25 to 59 years from five San Francisco, California, Bay Area counties were queried about their demographic characteristics, height, reported weight at age 25, cigarette smoking history, and oral contraceptive and sunscreen use. METHODS. Multiple logistic regression techniques were used to analyze the data. Forty-three percent of the women in the sample had never smoked more than 100 cigarettes, while 27% were current and 30% were former smokers. Separated or divorced women were more likely to have ever smoked. RESULTS. Women who were less educated, single, separated, or divorced or had smoked between 10 and 30 cigarettes per day were less likely to quit smoking. Women with less education and a longer history of smoking smoked more cigarettes per day. Women who had never smoked were more likely to use sunscreen and to report their weight as slightly less at age 25 than were smokers.     

Age at starting smoking and number of cigarettes smoked in Catalonia, Spain

BACKGROUND: Few studies have investigated the association between age at starting smoking and the average number of cigarettes smoked per day in adulthood. To provide further evidence on this issue, we analyzed data from the Catalan Health Interview Survey (CHIS). METHODS: The CHIS was conducted in 1994 on a randomly selected sample (N = 15,000) of the population of Catalonia, Spain. A total of 4,897 current or exsmokers (3,276 males and 1,621 females) were included for analysis. Age-standardized proportions of subjects smoking <15, 15-24, and >/=25 cigarettes/day, age-standardized mean number of cigarettes smoked per day, and multivariate odds ratios (OR) of being a heavy smoker (>/=25 cigarettes/day) according to age at starting smoking (<15, 15-17, 18-19, >/=20 years) were computed. RESULTS: Men who started smoking before the age of 15 smoked on average 5.5 cigarettes more than those who started at age 19 or over. Women who started smoking early in life smoked, on average, 6.8 cigarettes/day more than women who started later. The proportion of smokers of <15 cigarettes/day was higher among subjects who started smoking later. Both for males and for females, the OR of being a heavy smoker significantly increased with decreasing age at starting smoking (OR = 2.4 for males and 4.5 for females who started at age <15 versus >/=20 years). The level of education did not modify the relationship in males, whereas the association with age at starting was only apparent for more educated women. CONCLUSIONS: This study confirms that age at starting smoking is inversely and strongly associated to the number of cigarettes smoked per day. Thus, actions aimed at the prevention or delay of smoking onset among adolescents would have an important beneficial effect.     

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.     

Who stopped smoking? Results from a panel survey of living conditions in Sweden

1905 smokers were investigated from a random sample of 4424 persons among the Swedish population interviewed in 1974 and 1981. On average, 28% of those smoked in 1974 had stopped smoking by 1981. A multivariate method was used to study whether socioeconomic and demographic factors, tobacco consumption level or health contributed to changes in smoking behaviour. Most successful in smoking cessation were senior salaried employees (35% quit), well educated persons (33% quit) and those who smoked less than ten cigarettes per day (36% quit). On the other hand, only 20% of divorced parents with children succeeded in smoking cessation. Tobacco consumption turned out to be the most important variable for explaining the variance. The probability of smoking cessation increased by 40% if one smoked less than 10 cigarettes per day. The low explained variance, 6%, of this multivariate approach indicates, however, that socioeconomic factors have only marginal effects on the decision to stop smoking. It seems more likely that many factors, e.g. demographic, socioeconomic, motivational, self-efficacy, social and therapeutic support, nicotine dependence etc. act together in a complex way.     

Smoking cessation and lung cancer mortality in a cohort of middle-aged Canadian women

PURPOSE: To determine the impact of smoking cessation on lung cancer mortality among women. METHODS: Survival analysis is used to assess the effect of smoking cessation on lung cancer death in the dietary cohort of 49,165 women aged 40 to 59 years enrolled in the Canadian National Breast Screening Study. RESULTS: During an average of 10.3 years of follow-up, 106 women died of lung cancer. The risk of lung cancer mortality among women who quit before age 50 (HR=0.26; 95% CI, 0.13-0.55 among women who quit at ages 40-49) or quit in the previous 10 years (HR=0.39; 95% CI, 0.22-0.69) is substantially lower than the risk among current smokers. Women who quit after age 40 or have quit for less than 20 years are at substantially higher risk of lung cancer mortality compared with never smokers. Both duration of smoking cessation and age at quitting have independent effects on lung cancer mortality, after controlling for number of cigarettes smoked per day and number of years smoked, as well as other potential confounding variables. CONCLUSION: These findings suggest that programs and policies to promote early cessation of smoking and prevention of relapse should be a public health priority.     

Smoking habits and blood carbon monoxide levels

The carboxyhemoglobin concentrations (COHb) of 97 meat porters, 77 office workers, and 200 pregnant women have been determined. Individuals were questioned on smoking habits including numbers normally smoked per day, numbers already smoked on day of sampling, and time since last cigarette. The number of cigarettes smoked per day appears to allow the best prediction of COHb concentration. Individuals whose occupation involved them in physical exertion (meat porters) accumulated less carbon monoxide (CO) for numbers of cigarettes smoked per day than individuals smoking whilst sedentary. Pregnant women were seen to accumulate CO in a similar way to the active meat porters. In all groups, smokers had significantly higher COHb concentrations than nonsmokers. The effects of activity on CO uptake and elimination are discussed in relation to cigarette smoking, and it is suggested that the effect of activity on COHb is related more to elimination in the nonsmoking periods rather than uptake in the smoking periods.     

Effectiveness of a low-intensity intra-worksite intervention on smoking cessation in Japanese employees: a three-year intervention trial

To test the effectiveness of a low-intensity intervention program for smoking cessation targeting the worksite environment in employees who had a low readiness to quit, we conducted an intervention trial at six intervention and six control worksites in Japan. A total of 2,307 smokers at baseline who remained at their worksite throughout the three-year study period were analyzed (1,017 in intervention and 1,290 in control groups). The multi-component program at the worksites consisted of (1) presenting information on the harms of tobacco smoking and the benefits of cessation by posters, websites, and newsletters; (2) smoking cessation campaigns for smokers; (3) advice on designation of smoking areas; and (4) periodic site-visits of the designated smoking areas by an expert researcher. At baseline, the intervention and control groups each had high prevalence of immotive or precontemplation, that reflected low readiness to quit (71.5% and 73.2%, respectively). The smoking cessation rate, as not having smoked for the preceding six months or longer, assessed at 36 months after the baseline survey by a self-administered questionnaire was significantly higher in the intervention group than the control group (12.1%, vs. 9.4%, p=0.021). The intervention program still had a significant effect on the smoking cessation rate after multiple logistic regression analysis adjusted for sex, age, type of occupation, age of starting smoking, quit attempts in the past, number of cigarettes per day, and readiness to quit (odds ratio: 1.38, 95% confidence interval: 1.05-1.81, p=0.02). The cost per additional quitter due to the intervention was calculated to be Yen 70,080. These findings indicate that this program is effective and can be implemented in similar workplaces where the prevalence of smoking is high and smokers' readiness to cease smoking is low.     

Smoking habits in early pregnancy and attitudes towards smoking cessation among pregnant women and their partners.

One-hundred and eighty-seven general practitioners in western Norway recorded smoking habits among 2379 women, consulting for their first regular medical check-up in pregnancy. Forty-six per cent had been daily smokers the last 3 months before pregnancy. Thirty-nine per cent were still smoking at the time of their first check-up. Sixteen per cent of the daily smokers stopped smoking spontaneously during the first few weeks of pregnancy. Fifty-seven per cent of women younger than 20 and 28% of women 30 years and older, did smoke at the first check-up. Single women smoked more often than women living with a partner (58% versus 38%). Smoking habits were not associated with number of previous pregnancies. At the first check-up, 530 pregnant women, still smoking daily, 18-34 years of age, living with a partner, accepted to participate in a smoking intervention study. They filled in a questionnaire about their smoking habits, the smoking habits of their partners and their attitudes towards smoking cessation. Sixty-five per cent reported a reduction in their use of cigarettes after becoming pregnant. The mean reduction in the number of cigarettes smoked daily was 4.0 (31%). Most of the respondents expressed a strong motivation to quit or reduce their smoking habits during their pregnancy. Seventy-two per cent of the partners were daily smokers. Reduction in the consumption of cigarettes, negative attitudes towards smoking and determination to stop smoking was significantly higher among women who were encouraged by their partners to stop smoking and in those who perceived that their partners were willing to reduce their consumption.     

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.     

吸烟、饮酒对高血压病人死亡危险的研究——北京市东城区一千余例高血压病人平均7年前瞻性研究报告之一

本研究对1981年北京市居民中发现的1586名高血压患者作前瞻性观察,观察截止于1991年,平均追访7年(11340人年),死亡329人.分析结果表明,高血压患者每日吸烟量与总死亡及心血管病死亡均呈显著的正相关,用M-H法分层及Cox模型调整年龄、性别、血压、糖尿病等危险因素,趋势无改变.戒烟≥5年者,总死亡、心血管病及脑卒中死亡危险明显降低,心血管病、脑卒中死亡危险趋势同于非吸烟者.年龄≤65岁的高血压患者,特别是15～54岁年龄组,吸烟≥10支时可增高心血管病死亡危险2倍及以上,死亡危险在大量吸烟(每日≥20支)时也明显上升.结果还提示,少量饮酒(每天约0.8两白酒)有降低高血压病人死亡、心血管病死亡危险的作用.     

Smoking cessation and long-term weight gain in the Framingham Heart Study: an application of the parametric g-formula for a continuous outcome

Weight gain after smoking cessation can lessen the health benefits of, and reduce the incentives for, quitting smoking. Randomized clinical trials of smoking cessation have estimated this weight gain only over short periods of follow-up. We provide an estimate of long-term post-cessation weight gain in the Framingham Heart Study, a prospective observational study. We identified 2001 smokers free of diabetes, cancer, and cardiovascular disease in 1952. Using the parametric g-formula we estimated mean weight in 1972 if all smokers had quit at baseline versus if all had continued smoking. Our estimates were adjusted for demographic, socio-economic, and clinical factors at baseline and during follow-up. The estimated mean weight (95 % CI) at 20 years if all smokers had quit smoking was 75.2 kg (73.5, 76.6), compared with 70.2 kg (68.7, 71.8) if they had smoked 20 cigarettes/day and 73.4 kg (71.9, 74.6) if they had smoked 5 cigarettes/day (i.e., an estimated mean weight gain of 5.1 kg (3.1, 6.6) and 1.8 kg (0.8, 2.8), respectively). Smokers who were overweight or obese at baseline had a greater post-cessation weight gain on average. Our estimates suggest that smoking cessation can result in increases in body weight over 20 years. While the benefits of smoking cessation outweigh the risks due to post-cessation weight gain, our results highlight the need for long-term weight management interventions in combination with smoking cessation.