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

Greater smoking intensity may be linked to early smoking initiation among Filipinos: Evidence from the 2021 Global Adult Tobacco Survey Philippines

INTRODUCTION

Understanding the relationship between age at smoking initiation and later smoking intensity is crucial for assessing future health consequences of smoking early and informing strategies to prevent and reduce tobacco use. This study explores the relationship between the two smoking-related behaviors among Filipino daily smokers.

METHODS

Secondary data analyses from the 2021 Global Adult Tobacco Survey Philippines were performed. This study covers those who were reported to be daily smokers. The outcome of interest was smoking intensity, measured as the number of manufactured cigarettes consumed per day, while the main predictor was age at smoking initiation. Data from 2260 participants were analyzed. Negative binomial regression was used to test for the relationship between age at smoking initiation and smoking intensity while controlling for sociodemographic variables and other smoking-related behaviors.

RESULTS

The average age at which daily smoking commenced was 20.93 (SD=6.35) years, while the average number of manufactured cigarettes consumed per day was 9.50 (SD=7.26). Age at smoking initiation was a significant predictor of smoking intensity, even after controlling for potential confounders. Each additional year in the age at which smoking was initiated was associated with a 1.55% decrease in smoking intensity in the adjusted model (β= -0.0155, p<0.0001). Other predictors of smoking intensity were current age (β=0.0072; 95% CI: 0.0050-0.0094, p<0.0001), sex (β= -0.1146; 95% CI: -0.2157 - -0.0136, p=0.0262), and smoking rules at home (β=0.1807; 95% CI: 0.1175-0.2439, p<0.0001).

CONCLUSIONS

Greater smoking intensity may be linked to early smoking initiation among Filipino adult daily smokers. The results may support interventions that target younger ages to curb heavy tobacco use at later ages.

Relationship of cardiorenal risk factors with albuminuria based on age, smoking, glycaemic status and BMI: a retrospective cohort study of the UK Biobank data

Introduction

Smoking is harmful, and its cessation is recommended to prevent chronic kidney disease, which often begins with abnormal leakage of albumin in the urine, called albuminuria. Smoking cessation's effect on albuminuria depends on the pack-years smoked, length of abstinence, body mass index (BMI) and glycosylated haemoglobin (HbA1c). Using the UK Biobank data, we examined the relationship between these cardiorenal variables and albuminuria.

Methods

For this study, we selected a UK Biobank cohort with urinary albumin concentration (UAC) in the first and second visits. Participants were divided into progressor and regressor groups, where progressors were defined as those with increased UAC value, and regressors were those with decreased UAC value. Three different logistic regression models were fitted. In model 1, with a cohort design, we explored the impact of a change in age, HbA1c and BMI between the first and second visits and the UAC. In model 2 and 3, in a cross-sectional design, we explored which cardiorenal risk factors were associated with a rise or fall of UAC at the time point of the second visit. Results are expressed in OR and 95% CI.

Results

The prevalence of albuminuria was highest in ex-smokers who started smoking between the ages of 13 and 18. With a mean duration of 51 months, there was no statistically significant relationship between smoking status and BMI with albuminuria. Each year of ageing and each unit of increase in HbA1c (mmol/mol) increased the odds of progression of albuminuria by 20% and 3%, respectively. In ex-smokers, at the time point of the second visit, each year of smoking increased, and each year of abstinence decreased the odds by 4% and 6%, respectively.

Conclusion

Smokers should be supported to stop smoking and remain abstinent despite short-term weight gain. Childhood smoking should be actively discouraged.

Trends and Demographic Differences in the Incidence and Mean Age of Starting to Smoke Cigarettes Regularly, National Health Interview Survey, 1997-2018

OBJECTIVES

Surveillance of cigarette smoking behavior provides evidence for evaluating the impact of current tobacco control measures. We examined temporal changes and demographic differences in the incidence and mean age of starting to smoke cigarettes regularly in the United States.

METHODS

We conducted retrospective birth-cohort and cross-sectional analyses using self-reported data from the 1997-2018 National Health Interview Survey to evaluate trends and demographic differences in the incidence and mean age of starting to smoke cigarettes regularly among participants aged 18-84 years. We estimated the incidence and mean age of starting to smoke cigarettes regularly by using Poisson and linear regression.

RESULTS

Among adults born during 1950-1999, the incidence of starting to smoke cigarettes regularly before age 35 years decreased by 18.8% (95% CI, 17.0%-20.7%) per 10 years, with a peak incidence at age about age 18 years. Male, non-Hispanic White, and US-born people had a higher incidence of starting to smoke cigarettes regularly than female, other racial and ethnic, and non-US-born people, respectively (P < .001 for all). From 1997 to 2018, the mean age of starting to smoke cigarettes regularly decreased by 0.4% (95% CI, 0.2%-0.6%) per 10 years among adults who ever smoked.

CONCLUSION

The incidence of starting to smoke cigarettes regularly decreased dramatically at all ages during the study period, which suggests a positive impact of current tobacco control measures. For evaluating trends in starting to smoke cigarettes regularly, incidence can be a more sensitive indicator of temporal change than mean age. Differences in smoking incidence by demographic subgroup suggest that additional opportunities exist to further reduce the incidence of starting to smoke cigarettes regularly.

Modeling of smoking intensity by age at smoking onset among Iranian adult male using generalized additive model

Because the age at which a person first starts smoking has such a strong correlation with future smoking behaviours, it's crucial to examine its relationship with smoking intensity. However, it is still challenging to accurately prove this relationship due to limitations in the methodology of the performed studies. Therefore the main purpose of this study is to evaluate the potential risk factors affecting the intensity of smoking, especially the age of smoking onset among Iranian adult male smokers over 18 years of age using a generalized additive model (GAM). In GAM a latent variable with logistic distribution and identity link function was considered. Data from 913 Iranian male current smokers over the age of 18 was evaluated from a national cross-sectional survey of non-communicable disease (NCD) risk factors in 2016. Individuals were classified into: light, moderate, and heavy smokers. A GAM was used to assess the relationship. The results showed that 246 (26.9%) subjects were light smokers, 190 (20.8%) subjects were moderate smokers and 477 (52.2%) subjects were heavy smokers. According to the GAM results, the relationship was nonlinear and smokers who started smoking at a younger age were more likely to become heavy smokers. The factors of unemployment (OR = 1.364, 95% CI 0.725-2.563), retirement (OR = 1.217, 95% CI 0.667-2.223), and exposure to secondhand smoke at home (OR = 1.364, 95% CI 1.055-1.763) increased the risk of heavy smoking. but, smokers with high-income (OR = 0.742, 95% CI 0.552-0.998) had a low tendency to heavy smoking. GAM identified the nonlinear relationship between the age of onset of smoking and smoking intensity. Tobacco control programs should be focused on young and adolescent groups and poorer socio-economic communities.

Post-High School Changes in Tobacco and Cannabis Use in the United States

BACKGROUND

The transition from high school into young adulthood is a critical developmental period with many young people going to college, moving residence, and entering the work force for the first time. The NEXT Generation Health Study (NEXT) is a nationally representative longitudinal study of adolescent health behaviors. Previous NEXT research has found that the post-high school environment is associated with changes in alcohol use.

OBJECTIVES

The current study investigated the impact of school status, residential status, and work status on cannabis and cigarette use among post-high school participants.

RESULTS

Living in a dorm/fraternity/sorority was associated with an increased prevalence in cannabis use while attending a 4-year college was associated with a decreased prevalence in cigarette use.

CONCLUSIONS

Some aspects of the post-high school environment are related to cannabis and cigarette use. Differences in the social circumstances of cigarette and cannabis use and recent campaigns in colleges to reduce smoking may explain some of these trends.

Electronic cigarettes: an aid in smoking cessation, or a new health hazard?

The issue of electronic cigarettes is one of the most controversial topics in public health. There is intense debate and dividing opinions about their use patterns, health effects and association with smoking. This is expected since they were only recently introduced to the market and they refer to a harm-reduction approach and strategy that is not universally accepted for smoking and tobacco use in the public health community. Three main factors determine the public health impact of electronic cigarettes: (1) their safety/risk profile, both relative to smoking and in absolute terms; (2) their effectiveness for smoking reduction and cessation; (3) the patterns of use by different population subgroups, especially never-smokers, and adoption of use by youth. This analysis presents a brief overview of currently available evidence and gaps in research covering these three factors.

A comparison of adolescent smoking initiation measures on predicting future smoking behavior

Objectives

Evidence suggests that age at smoking initiation has implications for tobacco use, nicotine dependence, and resulting long-term health and chronic disease outcomes. The objective of the current study was to examine two different measures of smoking onset and to compare their validity in predicting future adolescent smoking survey.

Methods

Data from grades 9–12 students who participated in the 2012/2013 Youth Smoking Survey, a nationally-generalizable Canadian survey, and who had ever tried a cigarette, even a few puffs (n = 8126) were used in a multivariable logistic regression analysis to examine the association between age at smoking onset and current smoking behavior.

Results

Both “age at first puff” and “age at first whole cigarette” were significantly associated with current smoking status. Specifically, a delay of one year in the age at first puff was associated with lower odds of being a current smoker by 24% (AOR = 0.76, 95% CI = 0.73–0.79). Similarly, high school students who smoked their first whole cigarette at old age were less likely to report being a current smoker (AOR = 0.66, 95% CI = 0.62–0.71).

Conclusion

Efforts to prevent smoking uptake among youth, especially younger youth, are especially important in tobacco control efforts.

Tobacco smoking among school children in Colombo district, Sri Lanka

Tobacco smoking is an important problem among schoolchildren. The authors studied the patterns of tobacco smoking among schoolchildren in Colombo, Sri Lanka, using a self-administered questionnaire. Multistaged stratified random sampling was used to select 6000 students. Response rate was 90.7% (5446), out of which 53.4% were males. Prevalence rates for males and females, respectively, were as follows: having smoked at least 1 complete cigarette: 27.0% and 13.3%, smoked more than 100 cigarettes: 2.3% and 0.3%, daily smoking: 1.8% and 0.2%. Mean age of starting to smoke was 14.16 years. The tobacco products most used were cigarettes (91.5%) and bidis (3.8%). In univariate analysis, male gender, parental smoking, studying non-science subjects, peer smoking, and participating in sports were significantly associated with smoking of at least 1 complete cigarette (P < .05). In multivariate analysis, the most significant correlates were having close friends (odds ratio = 3.29, confidence interval = 2.47-4.37) or parents who smoked (odds ratio = 1.86, confidence interval = 1.28-2.71). Female smoking has increased from previously reported values. These high-risk groups can be targets for preventive programs.

Age at smoking initiation and subsequent smoking among Korean adolescent smokers

Objectives:

The aim of this study was to investigate the relationship between age at cigarette smoking initiation and smoking level among adolescent current smokers.

Methods:

In 2007, students from one or two classes of the 10th or 11th grade were randomly selected using the probability proportional to size sampling method. In total, 743 current smokers were included. Multiple logistic regression was used to determine the association between age at smoking initiation and smoking level as either frequent, daily, or heavy smokers.

Results:

The adjusted odds ratios for each smoking level were significantly higher for younger ages of smoking initiation than those for older ages of initiation were (p for trend <0.001). Compared with the students who started smoking in grades 10 to 11, the adjusted odds ratios for frequent, daily, and heavy smokers increased from 2.24 (95% confidence interval [CI], 1.30 to 3.87) to 3.90 (95% CI, 2.02 to 7.56), from 1.56 (95% CI, 0.92 to 2.62) to 3.17 (95% CI, 1.70 to 5.92), and from 2.56 (95% CI, 1.21 to 5.42) to 5.67 (95% CI, 2.61 to 12.30) with younger ages of smoking initiation.

Conclusions:

Smoking frequency and amount were closely associated with age at smoking initiation. Therefore, smoking prevention programs should be initiated from the young adolescent period.

Sex differences in yohimbine-induced increases in the reinforcing efficacy of nicotine in adolescent rats

Stress is an important factor in the initiation and maintenance of smoking in adolescents. Women are more vulnerable to the development of addiction to smoking and have more difficulty quitting than men. Women also showe enhanced responses to stress. Despite these differences, no work has been done examining the effects of stress on the reinforcing efficacy of self-administered nicotine in adolescent rats, or if there are sex differences. Male and female adolescent Long Evans rats were trained to self-administer one of three different intravenous doses of nicotine (7.5, 15, 30 μg/kg/infusion) first on fixed ratio, and then on a progressive ratio (PR) schedule beginning on postnatal day 33. The effect of the pharmacological stressor yohimbine (0.3, 0.6 mg/kg, i.p.) on the reinforcing efficacy of nicotine was then determined using the PR schedule. Yohimbine stimulated nicotine intake and increased PR breakpoints and numbers of infusions received in both male and female adolescent rats. The infusion dose of nicotine was positively associated with yohimbine-induced increases in responding. Female rats showed significantly increased breakpoints at yohimbine doses and nicotine infusion doses at which males did not. The effects of the pharmacological stressor, yohimbine on the reinforcing efficacy of nicotine are therefore linked to sex and nicotine infusion dose. Female rats are more sensitive to stress-induced potentiation of nicotine self-administration.

Distinct loci in the CHRNA5/CHRNA3/CHRNB4 gene cluster are associated with onset of regular smoking

Neuronal nicotinic acetylcholine receptor (nAChR) genes (CHRNA5/CHRNA3/CHRNB4) have been reproducibly associated with nicotine dependence, smoking behaviors, and lung cancer risk. Of the few reports that have focused on early smoking behaviors, association results have been mixed. This meta-analysis examines early smoking phenotypes and SNPs in the gene cluster to determine: (1) whether the most robust association signal in this region (rs16969968) for other smoking behaviors is also associated with early behaviors, and/or (2) if additional statistically independent signals are important in early smoking. We focused on two phenotypes: age of tobacco initiation (AOI) and age of first regular tobacco use (AOS). This study included 56,034 subjects (41 groups) spanning nine countries and evaluated five SNPs including rs1948, rs16969968, rs578776, rs588765, and rs684513. Each dataset was analyzed using a centrally generated script. Meta-analyses were conducted from summary statistics. AOS yielded significant associations with SNPs rs578776 (beta = 0.02, P = 0.004), rs1948 (beta = 0.023, P = 0.018), and rs684513 (beta = 0.032, P = 0.017), indicating protective effects. There were no significant associations for the AOI phenotype. Importantly, rs16969968, the most replicated signal in this region for nicotine dependence, cigarettes per day, and cotinine levels, was not associated with AOI (P = 0.59) or AOS (P = 0.92). These results provide important insight into the complexity of smoking behavior phenotypes, and suggest that association signals in the CHRNA5/A3/B4 gene cluster affecting early smoking behaviors may be different from those affecting the mature nicotine dependence phenotype.

Earlier age of smoking initiation may not predict heavier cigarette consumption in later adolescence

Previous studies suggest that earlier cigarette smoking initiation in adolescence predicts greater cigarette consumption later in adolescence or adulthood. Results from these studies have been used to inform interventions for adolescent smoking. However, previous studies suffer from several important methodological limitations. The objective of the present study was to address these limitations by longitudinally and prospectively examining whether and how age of initiation of smoking among adolescents predicts cigarette consumption by age 16 or 17. Participants completed an in-class survey every 6 months for 2-3 school years. Participants included 395 adolescents (Mean age=14 years at baseline; 53.2% female) from two public high schools in Northern California (Schools A and B) who completed self-report measures of smoking initiation, number of friends who smoke, and number of whole cigarettes smoked by the final survey time point. Adolescents who were older when they first smoked one whole cigarette were 5.3 to 14.6 times more likely in School A and 2.9 to 4.3 times more likely in School B to have smoked a greater number of cigarettes by age 16 or 17. Results suggested that earlier smoking initiation may not lead to heavier cigarette consumption later in time, as has been previously shown. There may be a period of heightened vulnerability in mid- or late adolescence where smoking experimentation is more likely to lead to greater cigarette consumption. Targeting prevention efforts to adolescents aged 14 to 17 years may further reduce smoking initiation among youth, thus limiting subsequent smoking-related morbidity and mortality in adulthood.

Determinants of heavy cigarette smoking: are there differences in men and women? Results from the population-based MONICA/KORA Augsburg surveys

INTRODUCTION

Heavy cigarette smoking is more frequent in men than in women. So far, little is known whether this sex-specific difference in cigarette consumption is modified by age at smoking onset, sociodemographical, and lifestyle factors. Therefore, we aimed to identify sex-specific characteristics associated with heavy daily cigarette smoking.

METHODS

The study population consisted of 3,178 daily smokers aged 25-74 years from the population-based MONICA/KORA Augsburg surveys conducted between 1984 and 1995. Subjects consuming at least 20 cigarettes daily were defined as heavy smokers. Multivariate logistic regression was used to identify sociodemographical, smoking-related, and lifestyle characteristics of heavy smokers.

RESULTS

A number of 1,576 subjects (49.6%) were identified as heavy smokers. Men were significantly more often heavy smokers than women with the exception of those women who have started smoking at an early age. Multivariate logistic regression revealed early age at smoking onset determines heavy smoking in women but not in men. While younger age at study examination and low educational level was associated with heavy smoking in men only, current employment was associated with heavy smoking in women only. Moreover, living alone, high alcohol or coffee consumption, and low physical leisure activity were associated with heavy smoking behavior in both sexes. Survey, obesity and parental history of smoking showed no association with heavy smoking.

CONCLUSIONS

The present study revealed sex-specific differences in heavy smoking by age at smoking onset, which was not shown before so far. These findings should be further investigated and addressed in future prevention campaigns.

Patterns of smoking among adolescents in Malaysia and Thailand: findings from the International Tobacco Control Southeast Asia survey

At present, 70% of the world's 1.1 billion smokers are in developing countries, with over 50% in Asia alone. The current study examined patterns of youth smoking in Thailand and Malaysia. Respondents were 2002 youths between the ages of 13 and 17 from Thailand (n = 1000) and Malaysia (n = 1002). Respondents were selected using a multistage cluster sampling design and surveyed between January 2005 and March 2005. Approximately 3% of youth between the ages of 13 and 17 were current smokers, with an additional 10% to 12% reporting experimental smoking. Males were between 7 and 15 times more likely to report smoking behavior than females. Less than 1% of females respondents in either country met the criteria for current smoking, and less than 5% met the criteria for experimental smoking. In contrast, more than 50% Thai males and approximately one-third of Malaysian males aged 17 met the criteria for either experimental or current smoking.

Acquisition of nicotine self-administration in adolescent rats given prolonged access to the drug

As most human tobacco use begins during adolescence and ongoing development of the adolescent central nervous system could affect acquisition of nicotine self-administration (SA), our established rat SA procedure was modified to study adolescent acquisition of SA with prolonged access to nicotine (23 h/day). Postnatal age 43-45 female Lewis rats, without prior shaping, conditioning, or food deprivation, were housed in operant chambers equipped with two levers; pressing the active lever triggered an i.v. injection of nicotine. By the 10th day of SA, rats receiving 7.5, 15, 30, or 60 microg/kg/injection nicotine (free base) obtained 23+/-16, 50+/-8, 65+/-8, or 48+/-5 injections (mean+/-SE), respectively. In the 30 microg/kg/injection group, active : inactive ratio was greater than 2 after SA day 4; 92% of injections occurred during the 12-h active (dark) phase of the light cycle. Main effects (analysis of variance) were shown for day and lever (ie active vs inactive) (p<0.001). Adolescent males showed similar dose-dependent nicotine SA. With the increasing workload imposed by raising the fixed ratio (FR), less nicotine was self-administered at FR 5 and 7 compared to FR 1 and 3. In comparison to adult females self-administering 30 microg/kg/injection of nicotine at FR 1, adolescents acquired nicotine SA at an accelerated rate (p<0.05) and received a greater number of injections (p<0.05) by day 10. In conclusion, when given prolonged access to the drug, both female and male adolescent Lewis rats rapidly acquire nicotine SA within the dosage range and FR constraints previously observed in adult Lewis rats. However, adolescent females acquired the behavior more rapidly and attained higher levels of stable nicotine SA than adults.

[Cognitive factors associated with smoking initiation in adolescents]

OBJECTIVE

To study the association between cognitive factors of the behavioral change model "Attitude Self Efficacy" (ASE) at different phases of smoking initiation among adolescents.

METHODS

We carried out a cross-sectional survey among students in the second grade of Compulsory Secondary Education (13-14 years old) from Cornellà de Llobregat (Barcelona, Spain) in 2000 to obtain information on cognitive factors and smoking. Logistic regression analysis was used to investigate the variables associated with smoking (odds ratio [OR] of experimenters vs. non-smokers and of smokers vs. experimenters).

RESULTS

The prevalence of daily smoking was 22.9% (95% CI, 16.5%-29.3%) among boys and 36.2% (95% CI, 29.7%-42.6%) among girls. Factors associated with experimenting (vs. non-smoking) were: attitudes to smoking (disagreement with smoke-free areas [OR = 3.46; 95% CI, 1.65-7.24], agreement with smoking promotion [OR = 3.42; 95% CI, 1.42-8.28]), and subjective norms (perceiving friends as smokers [OR = 2.50; 95% CI, 1.17-5.35]). The variables associated with regular smoking (vs experimenting) belong to: self-efficacy and attitudes to smoking.

CONCLUSIONS

Focussing on subjective norms and smoking attitudes with programs targetted younger ages seems appropriate, since these factors are more closely associated with the experimenting phase. Encouraging skills to refuse cigarettes offered by friends is appropriate at a more advanced age, since this determinant is associated with the change from experimenting to regular smoking.

A preliminary investigation of early smoking initiation and nicotine dependence in Korean adults

BACKGROUND

Few studies have investigated the association between age at smoking initiation and Fagerström test for nicotine dependence (FTND) in adulthood. The goal of this study was to develop the Korean version of FTND (FTND-K) and to examine the relationship between age at smoking initiation and nicotine dependence.

METHODS

This investigation used data from 268 current smokers who visited the Center for Cancer Prevention and Early Detection in the National Cancer Center, Korea. The internal consistency of the FTND-K was assessed by Cronbach's coefficient alpha. Pearson's correlation coefficients were used to assess the relationships between the FTND-K sum scores and urinary cotinine levels. One-way analysis of variance (ANOVA) and t-tests were used to assess differences in the FTND-K sum score between groups. Factor associated with nicotine dependence were identified through stepwise multiple logistic regression analysis.

RESULTS

The standardized Cronbach's alpha of FTND-K was 0.72. A significant positive correlation was seen between the FTND-K sum score and urinary cotinine level (correlation coefficient = 0.49, P < 0.05). Age at smoking initiation had a significant association with the FTND-K sum score in univariate analysis. In multivariate analysis, nicotine dependence was higher in smokers that started smoking cigarettes at 19 years or earlier than in those that started at 25 years or later (OR = 11.25, 95% CIs, 1.46-97.10).

CONCLUSIONS

The FTND-K is a valid assessment tool of nicotine dependence with acceptable levels of internal consistency and close correlation to urinary cotinine level. The finding that those who initiate smoking at an early age tend to be more nicotine dependent underscores and reinforces the public health significance of delaying smoking onset.

Young adolescents, tobacco advertising, and smoking

BACKGROUND

In adolescents aged 12-14, we measured attitudes to tobacco advertising. Our purpose is to understand the relation of these attitudes to tobacco use and identify the groups most influenced by the advertising.

METHODS

Survey of adolescents on Gran Canaria Island, Spain, about aspects of family, school, peers, tobacco consumption, and tobacco advertising. The subjects of the double-stratified cluster sample were 1910 students at the same grade level in 33 schools; 86.6% were 13 or 14 years old, and 51.2% were boys. We generated measures for attitudes to tobacco advertising from replies to seven questions with ordinal scales by an analysis of categorical principal components. To relate attitude to tobacco advertising and the profiles of these adolescents, we used multiple regression and logistic regression models.

RESULTS

Attitudes to tobacco advertising are related to some home and school factors, but most significantly to tobacco and alcohol consumption, to amount of time at home without adults, and to peer influence.

CONCLUSIONS

It is possible to draw up profiles of the students most vulnerable to tobacco advertising, and to cluster them in two groups, the "vitalists" and the "credulous." The effect of cigarette ads is different between these groups. This study can help to orientate smoking prevention.

Lasting effects of adolescent nicotine exposure on the electroencephalogram, event related potentials, and locomotor activity in the rat

Tobacco smoking initiated during adolescence is often associated with rapid onset of dependence and difficulty in maintaining abstinence. Animal models have demonstrated that adolescent nicotine exposure causes cell death and altered neurochemistry in the cortex and hippocampus; however, little is known about the neurophysiological consequences of adolescent nicotine exposure in the adult. The primary objective of this study was to assess the consequences of adolescent nicotine exposure on the adult electroencephalogram (EEG) and event-related potentials. Male Sprague-Dawley rats were administered nicotine (5.0 mg/kg per day) for 5 days between postnatal days 35 and 40 using transdermal nicotine patches. Following 6-7 weeks of nicotine withdrawal, EEG activity and event related potentials were assessed. Motor activity and sucrose preference were also examined during the nicotine withdrawal period. Additionally, a set of rats was exposed to multiple doses of nicotine for a single day to assess nicotine and cotinine blood levels. Transdermal nicotine produced nicotine (88+/-21.5 ng/ml) and cotinine (647.6+/-123.2 ng/ml) levels comparable to those previously reported. Reduced motor activity, decreased 1-4 Hz power in the cortical electroencephalogram, and increased cortical N1 amplitude were observed in nicotine-exposed rats compared to controls. These data demonstrate that transdermal nicotine patches provide an effective and non-invasive nicotine delivery system for the adolescent rat. The combined neurophysiological and locomotor activity changes observed in nicotine-exposed rats demonstrate that adolescent nicotine exposure has lasting neurobehavioral consequences. These changes may be indicative of a lasting 'nicotine abstinence syndrome' characterized by increased arousal, anxiety, or emotionality.

Assessing 'stage of change' in current and former smokers

AIMS

The concept of 'stage of change' is widely used by researchers and clinicians in the field of smoking cessation. Our aim was to assess the validity of three staging questionnaires and of the concept of 'stage of change' itself.

SETTING AND PARTICIPANTS

Survey on the Internet in 1025 ever smokers, retest after 8 days in 318 people (31%), follow-up after 32 days in 451 people (44%).

MEASUREMENTS

Three measures of 'stage of change'.

FINDINGS

Participants (83-93%) were classified in the same stage by all pairs of questionnaires, and 15% changed stage during an interval of 8 days. Including quit attempts in the 'preparation' stage had a large impact on stage distributions, because 18-24% of smokers who had decided to quit in the next 30 days were downgraded to the 'contemplation' stage as they had not made a quit attempt in the previous year. The 'action' stage included 5-7% of occasional smokers. Quit attempts during the past 7 days and 30 days were better predictors of smoking cessation than quit attempts during the past 12 months. Baseline stage and a continuous measure of intention predicted smoking abstinence at follow-up.

CONCLUSIONS

These results reflect theoretical and methodological problems with the concept of stage of change. 'Stage' covers four different variables: current behaviour, quit attempts, intention to change and time since quitting. These variables are combined in a somewhat haphazard manner, none of them is measured comprehensively, and intention and time are continuous variables categorized by arbitrary cutpoints. Measuring each of these four variables independently may be preferable to using an incomplete mix of these elements.

Recent decline in cancer mortality in Catalonia (Spain). A joinpoint regression analysis

The aim of this paper was to analyse recent changes in cancer mortality in Catalonia (Spain) between 1975 and 1998 using joinpoint regression models. Mortality data were obtained from the Mortality Registry of Catalonia. For each sex, age-standardised (standard world population) mortality rates were computed by the direct method, and joinpoint analysis was used to identify the best fitting points where a statistically significant change in the rates had occurred. In men, the overall cancer mortality (except skin non-melanoma) was highest in 1991 and decreased thereafter. Lung cancer was the main cause of cancer mortality, with an increase until 1989, and a subsequent levelling off (-0.8% annual between 1989 and 1998). Colorectal cancer was the second cause of cancer death, both in men and women, with a levelling-off of the rates since 1991 and 1989, respectively. In women, the mortality rate decreased for total cancer (except skin non-melanoma) since 1991 (-0.9% annually). Breast cancer increased until 1975, levelled-off and begun to decline since 1992 (-3.8% annual). Lung cancer increased since 1988 (+2.1%) and became the third cancer cause of death among women in 1998. These changes are mainly due to the decline of smoking prevalence in males, but not in females, and to the introduction of new diagnostic techniques and improved therapies for female breast cancer.

Smoking initiation and cessation by gender and educational level in Catalonia, Spain

BACKGROUND

The role of gender and socioeconomic status in smoking has been characterized in the United States and Northern European countries. However, there is scarce information of the dynamic of the tobacco epidemic in Southern European countries. The aim of this study was to analyze smoking initiation and cessation according to level of education and gender in Catalonia, Spain.

METHODS

Data from the Catalan Health Survey (1994), a cross-sectional study based in a representative sample of the noninstitutionalized population of Catalonia, was used. The relative risks and 95% confidence interval of smoking initiation were computed by means of Cox's regression. The odds ratios and 95% confidence intervals of quitting smoking were derived from logistic regression models. Direct responses from 4,370 men and 5,213 women ages 25 years or over were included for analysis.

RESULTS

Ever smoking was inversely related to level of education in men. Males with the highest educational level tended to have a lower probability of being a smoker at a given age than those with less than primary school (relative risk = 0.6; 95% confidence interval: 0.5-0.7). This pattern appeared with small variation across age groups. In women, a reverse trend was present: the higher the level of education the higher the relative risk of starting smoking (relative risk = 4.6; 95% confidence interval: 3.1-6.7). Quitting smoking was more likely among men and women with higher education as compared to men and women with less than primary school (men: odds ratio = 1.5; 95% confidence interval 1.1-2.1; women: odds ratio = 4.6; 95% confidence interval: 2.1-10.4).

CONCLUSIONS

The differential effect of education according to gender may reflect different phases of the smoking epidemic. In Catalonia, the transition of smoking from upper and lower socioeconomic groups occurred recently among men, and women have currently begun to experience this transition.

Pattern of smoking initiation in Catalonia, Spain, from 1948 to 1992

OBJECTIVES

This study analyzed the pattern of smoking initiation by sex and educational level in Catalonia, Spain.

METHODS

Data from the 1994 Catalan Health Interview Survey were used (n = 12,245). The age and smoking status of each subject were reconstructed for each calendar period. Age-specific smoking initiation rates were calculated.

RESULTS

Smoking initiation among females was rare until the 1960s, but from the period 1968-1972 onward a converging pattern was observed between the genders. Women with higher levels of education started smoking before other women, but the gradient of educational level has changed in recent years, with higher initiation rates among less-educated women.

CONCLUSIONS

These results are consistent with diffusion-of-innovations theory and could be related to social and economic changes from the 1960s onward in Spain.