The impact of smoking habits on lung cancer risk: 28 years' observation of 26,000 Norwegian men and women

Lung Cancer Screening in Asia: An Expert Consensus Report

INTRODUCTION

The incidence and mortality of lung cancer are highest in Asia compared with Europe and USA, with the incidence and mortality rates being 34.4 and 28.1 per 100,000 respectively in East Asia. Diagnosing lung cancer at early stages makes the disease amenable to curative treatment and reduces mortality. In some areas in Asia, limited availability of robust diagnostic tools and treatment modalities, along with variations in specific health care investment and policies, make it necessary to have a more specific approach for screening, early detection, diagnosis, and treatment of patients with lung cancer in Asia compared with the West.

METHOD

A group of 19 advisors across different specialties from 11 Asian countries, met on a virtual Steering Committee meeting, to discuss and recommend the most affordable and accessible lung cancer screening modalities and their implementation, for the Asian population.

RESULTS

Significant risk factors identified for lung cancer in smokers in Asia include age 50 to 75 years and smoking history of more than or equal to 20 pack-years. Family history is the most common risk factor for nonsmokers. Low-dose computed tomography screening is recommended once a year for patients with screening-detected abnormality and persistent exposure to risk factors. However, for high-risk heavy smokers and nonsmokers with risk factors, reassessment scans are recommended at an initial interval of 6 to 12 months with subsequent lengthening of reassessment intervals, and it should be stopped in patients more than 80 years of age or are unable or unwilling to undergo curative treatment.

CONCLUSIONS

Asian countries face several challenges in implementing low-dose computed tomography screening, such as economic limitations, lack of efforts for early detection, and lack of specific government programs. Various strategies are suggested to overcome these challenges in Asia.

Expression patterns and clinical significance of estrogen receptor in non-small cell lung cancer

BACKGROUND

Lung cancer death remains the highest among all malignancies. Gender differences show women have an increased cancer incidence while men have worse outcomes. These observations identified that some lung carcinomas express estrogen receptors (ER). This is a promising target as antiestrogen drugs can reduce tumors and improve survival. However, there is a limited understanding of ER distribution and its clinical significance to properly design antiestrogen drug clinical trials. Thus, we comprehensively analyzed ERα and ERβ expression patterns by gender, cancer cell type, and receptor location in lung cancer.

METHODS

We conducted a systematic review using the PubMed database from all-time through October 2022, using MeSH terms with the keywords "lung cancer," "estrogen receptor," and "immunohistochemistry." We identified 120 studies with 21 reports being evaluated based on our inclusion criteria.

RESULTS

We examined 4874 lung cancers from 5011 patients. ERβ is the predominant form of ER expressed, mainly found in the nucleus. The ERβ positivity rate is 51.5% in males versus 55.5% in females and was not statistically different. In contrast, ERα is predominately extranuclear in location, and ERα expression varies by gender. Males had a positivity rate of 31% versus 26.6% in females, which is statistically different. ERα is associated with a worse prognosis in some studies, while it had no effect in others. Overall, ERβ was associated with a better prognosis.

CONCLUSION

We characterized ER expression patterns in 4874 lung cancers. Over 50% expressed ERβ with equal rates in both sexes and was associated with a better prognosis. ERα expression was slightly higher in males (31%) than females (26.6%) and was associated with a poor prognosis. Our findings suggest estrogen signaling may be a promising drug target in lung cancer.

Nationwide lung cancer screening with low-dose computed tomography: implementation and first results of the HUNCHEST screening program

OBJECTIVES

Lung cancer (LC) kills more people than any other cancer in Hungary. Hence, there is a clear rationale for considering a national screening program. The HUNCHEST pilot program primarily aimed to investigate the feasibility of a population-based LC screening in Hungary, and determine the incidence and LC probability of solitary pulmonary nodules.

METHODS

A total of 1890 participants were assigned to undergo low-dose CT (LDCT) screening, with intervals of 1 year between procedures. Depending on the volume, growth, and volume doubling time (VDT), screenings were defined as negative, indeterminate, or positive. Non-calcified lung nodules with a volume > 500 mm³ and/or a VDT < 400 days were considered positive. LC diagnosis was based on histology.

RESULTS

At baseline, the percentage of negative, indeterminate, and positive tests was 81.2%, 15.1%, and 3.7%, respectively. The frequency of positive and indeterminate LDCT results was significantly higher in current smokers (vs. non-smokers or former smokers; p < 0.0001) and in individuals with COPD (vs. those without COPD, p < 0.001). In the first screening round, 1.2% (n = 23) of the participants had a malignant lesion, whereas altogether 1.5% (n = 29) of the individuals were diagnosed with LC. The overall positive predictive value of the positive tests was 31.6%. Most lung malignancies were diagnosed at an early stage (86.2% of all cases).

CONCLUSIONS

In terms of key characteristics, our prospective cohort study appears consistent to that of comparable studies. Altogether, the results of the HUNCHEST pilot program suggest that LDCT screening may facilitate early diagnosis and thus curative-intent treatment in LC.

KEY POINTS

• The HUNCHEST pilot study is the first nationwide low-dose CT screening program in Hungary. • In the first screening round, 1.2% of the participants had a malignant lesion, whereas altogether 1.5% of the individuals were diagnosed with lung cancer. • The overall positive predictive value of the positive tests in the HUNCHEST screening program was 31.6%.

Differential exposure to 33 toxic elements through cigarette smoking, based on the type of tobacco and rolling paper used

Environmental pollution due to various elements is increasing all across the planet owing to their use in industrial processes. The tobacco plants and the vegetables used in the manufacturing of smoking paper may accumulate these elements from the environment. Thus, tobacco and smoking paper may be relevant contributors among the content of elements in cigarettes, including some emerging pollutants such as rare earth elements (REEs). Thirty-two elements related to hi-tech industrial processes were analyzed in tobacco, rolling paper, and filters (n = 257 samples) by ICP-MS. A variety of industrial brands and "roll-your-own" cigarette papers were considered. The potential maximum daily exposure to these elements by a hypothetical heavy smoker was calculated for each type of cigarette. We found significant differences in the levels of most elements, both in the tobacco and in the paper. Black tobacco cigarettes contained the maximum levels. We found that the paper used in roll-your-own cigarettes may significantly modify their concentration of elements. Fast-burning, bleached, and flavored papers also contribute to higher levels of these pollutants. Thus, the differences in theoretical exposure depending on the type of cigarette consumed-either branded or hand-rolled-may be very striking, of up to 35-40 times. In addition to the number of cigarettes consumed per day, it is necessary to consider the type of cigarette consumed to assess the risk of exposure to toxic elements. Tobacco paper is a prominent source of exposure to toxic elements. Cigarette smoke is another source of exposure to emerging contaminants such as REE.

Smoking as a risk factor for lung cancer in women and men: a systematic review and meta-analysis

OBJECTIVES

To investigate the sex-specific association between smoking and lung cancer.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

We searched PubMed and EMBASE from 1 January 1999 to 15 April 2016 for cohort studies. Cohort studies before 1 January 1999 were retrieved from a previous meta-analysis. Individual participant data from three sources were also available to supplement analyses of published literature.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Cohort studies reporting the sex-specific relative risk (RR) of lung cancer associated with smoking.

RESULTS

Data from 29 studies representing 99 cohort studies, 7 million individuals and >50 000 incident lung cancer cases were included. The sex-specific RRs and their ratio comparing women with men were pooled using random-effects meta-analysis with inverse-variance weighting. The pooled multiple-adjusted lung cancer RR was 6.99 (95% Confidence Interval (CI) 5.09 to 9.59) in women and 7.33 (95% CI 4.90 to 10.96) in men. The pooled ratio of the RRs was 0.92 (95% CI 0.72 to 1.16; I2=89%; p<0.001), with no evidence of publication bias or differences across major pre-defined participant and study subtypes. The women-to-men ratio of RRs was 0.99 (95% CI 0.65 to 1.52), 1.11 (95% CI 0.75 to 1.64) and 0.94 (95% CI 0.69 to 1.30), for light, moderate and heavy smoking, respectively.

CONCLUSIONS

Smoking yields similar risks of lung cancer in women compared with men. However, these data may underestimate the true risks of lung cancer among women, as the smoking epidemic has not yet reached full maturity in women. Continued efforts to measure the sex-specific association of smoking and lung cancer are required.

Differences in nicotine dependence, smoke exposure and consumer characteristics between smokers of machine-injected roll-your-own cigarettes and factory-made cigarettes

BACKGROUND

Consumption of machine-injected roll-your-own (RYO) filtered cigarettes made from pipe tobacco increased almost 7-fold from 2008 to 2011 in the United States.

METHODS

We used data from the Pennsylvania Adult Smoking Study to compare the differences in sociodemographic, smoking topography, nicotine dependence, and cotinine levels between 280 smokers using factory made (FM) cigarettes and 68 smokers using RYO cigarettes.

RESULTS

RYO smokers were older (41 vs. 37, P = 0.053), had significantly lower levels of income (P < 0.001) and education (P = 0.007), and were less likely to be fully employed (P = 0.009). RYO smokers consumed more cigarettes per day [CPD] (21 vs. 15, P < 0.001), and had a higher mean score on the Fagerström Test for Cigarette/Nicotine Dependence (5.2 vs. 4.1, P < 0.001). The main reasons for choosing RYO cigarettes were the lower cost (68%) and believed they are less harmful (12%). The average cost per pack of FM cigarettes was $5.74 vs. $1.13 for RYO. In multiple regression analyses, RYO smokers had significantly lower cotinine levels across all levels of CPD. Among smokers of king-size cigarettes, mean interpuff interval (P < 0.05) and total smoke duration (P < 0.01) per cigarette was significantly greater in RYO smokers. In laboratory measurements, RYO cigarettes contained more tobacco by weight than FM cigarettes, but weight varied by both tobacco and cigarette tube brands.

CONCLUSIONS

Machine-injected RYO cigarettes made from pipe tobacco are cheaper than FM cigarettes but may have higher abuse liability. Smokers who might otherwise reduce their cigarette consumption or quit altogether may continue to smoke RYO cigarettes due to their affordability.

Clinicopathological and molecular epidemiological study of lung cancer patients seen at a tertiary care hospital in Northern India

Aims:

The primary objective of this study was to estimate the clinicopathological and molecular profile of lung cancer patients along with the evaluation of their clinical characteristics at a tertiary care hospital in Northern India.

Subjects and Methods:

A total of 421 patients with lung cancer histology who were treated at Max Super Speciality Hospitals were included in the study. The study protocol conforms to the ethical guidelines of the 1975 Declaration of Helsinki and permission was obtained from the Ethics Committee before the start of the study. Clinical characteristics and molecular profiling data were collected from the patient's medical records.

Results:

There were 330 (78.4%) men and 91 (21.6%) women with a median age of 62 years (range: 30–93 years). Of the 421 patients, 388 (92.2%) patients had the nonsmall cell lung cancer (NSCLC) histology whereas 33 (7.8%) patients were of SCLC histology. Histology and gender had a significant association with NSCLC and SCLC (P < 0.05). Epidermal growth factor receptor (EGFR) and echinoderm microtubule-associated protein like 4-anaplastic lymphoma kinase (EML4-ALK) fusion gene testing was done in 120 and 93 patients, respectively. Of the 120 patients, 24 (20%) cases were positive for EGFR mutations whereas EML4-ALK fusion gene was present in 8 (8.6%) out of 93 patients.

Conclusions:

Our study confirms the importance of molecular testing in the NSCLC patient subgroup with an aim to identify the exact molecular targets that can benefit from the newer generation of targeted therapies.

Are male and female smokers at equal risk of smoking-related cancer: evidence from a Swedish prospective study

This study examines sex differences in the relative risks of lung cancer and other smoking-related cancers (i.e. cancers of the upper respiratory tract, oesophagus, pancreas, bladder, and renal pelvis). Data on smoking habits in 1963 from a random sample of 56,000 men and women were linked with information on new cases of cancer for 1964 - 89. Compared with people who have never smoked, the relative risks of lung cancer at different levels of pack-years completed in 1963 (>5, 6 - 15, 16 - 25 and 25+ pack-years) were 1.6, 4.4, 14.2, and 17.9 for men, and 2.1, 6.3, 10.3, and 16.5 for women. The corresponding relative risks of other smoking-related cancers were 1.8, 3.0 5.4, and 6.4 for men, and 2.0, 3.1, 5.0, and 6.5 for women. These results suggest that men and women have similar relative risks of smoking-related cancers at different levels of smoking.

SmokeHaz: Systematic Reviews and Meta-analyses of the Effects of Smoking on Respiratory Health

BACKGROUND

Smoking tobacco increases the risk of respiratory disease in adults and children, but communicating the magnitude of these effects in a scientific manner that is accessible and usable by the public and policymakers presents a challenge. We have therefore summarized scientific data on the impact of smoking on respiratory diseases to provide the content for a unique resource, SmokeHaz.

METHODS

We conducted systematic reviews and meta-analyses of longitudinal studies (published to 2013) identified from electronic databases, gray literature, and experts. Random effect meta-analyses were used to pool the findings.

RESULTS

We included 216 articles. Among adult smokers, we confirmed substantially increased risks of lung cancer (risk ratio (RR), 10.92; 95% CI, 8.28-14.40; 34 studies), COPD (RR, 4.01; 95% CI, 3.18-5.05; 22 studies), and asthma (RR, 1.61; 95% CI, 1.07-2.42; eight studies). Exposure to passive smoke significantly increased the risk of lung cancer in adult nonsmokers and increased the risks of asthma, wheeze, lower respiratory infections, and reduced lung function in children. Smoking significantly increased the risk of sleep apnea and asthma exacerbations in adult and pregnant populations, and active and passive smoking increased the risk of tuberculosis.

CONCLUSIONS

These findings have been translated into easily digestible content and published on the SmokeHaz website.

Youth Preferences for Roll-Your-Own Versus Factory-Made Cigarettes: Trends and Associations in Repeated National Surveys (2006-2013) and Implications for Policy

INTRODUCTION

We investigated trends in roll-your-own (RYO) and factory-made (FM) cigarette use over time among youth in New Zealand (NZ), a high RYO use country. We also explored factors associated with RYO use.

METHODS

We analyzed data from an annual survey of NZ students (14-15 years old) from 2006-2013. Smokers were asked whether they usually smoked RYO or FM cigarettes, and provided details of their source of supply. We estimated prevalences and developed a binary logistic regression model to explore determinants of RYO use.

RESULTS

Between 6663 (2006) and 3143 (2013) current smokers responded. Each year, around 80% reported usually smoking RYO or FM cigarettes. The proportion reporting usual RYO use was 45% (95% confidence interval [CI] ±3%) in 2006, reducing to 40% (95% CI ±3%) in 2013 (trend test: P < .001). By contrast, the proportions reporting usual FM use increased slightly over time from 36% (95% CI ±3%) in 2006 to 38% (95% CI ±3%) in 2013 (trend test: P < .001). Usual RYO use was more common amongst regular smokers, those who initiated smoking younger, who belonged to low or medium socioeconomic status groups, and whose friends and family both smoked.

CONCLUSIONS

RYO use is very high among NZ youth who smoke. Preference for RYO cigarettes amongst longer-term, regular smokers suggests RYO tobacco supports and maintains youth smoking. There was some initial evidence that a 2010 differential tax increase on RYO tobacco was associated with a shift away from usual RYO use amongst those who sourced tobacco from caregivers or friends. Additional measures such as further differential excise tax increases appear warranted.

Trends and socioeconomic differences in roll-your-own tobacco use: findings from the ITC Europe Surveys

OBJECTIVES

To examine if exclusive Roll-Your-Own (RYO) tobacco use relative to factory-made (FM) cigarette use has been rising over time, to determine the extent to which economic motives and perceptions that RYO cigarettes are less harmful act as primary motivations for use, and to examine the association of income and education with the level of RYO tobacco use among smokers in four European countries.

METHODS

Data were obtained from the International Tobacco Control (ITC) Europe Surveys, and a cohort sample of 7070 smokers from the Netherlands, Germany, France and UK were interviewed between June 2006 and December 2012. Generalised estimating equations (GEE) were used to assess trends in RYO use, and whether RYO consumption varied by socioeconomic variables.

RESULTS

Exclusive RYO use over the study period has increased significantly in the UK from 26.4% in 2007 to 32.7% in 2010 (p<0.001); France from 12.2% in 2006 to 19.1% in 2012 (p<0.001); and Germany from 12.7% in 2007 to 18.6% in 2011 (p=0.031), with increased borderline significantly in the Netherlands (31.7% to 34.3%, p=0.052), from 2008 to 2010. Over three-quarters of users in each of the study countries indicated that lower price was a reason why they smoked RYO. Just over a fourth of smokers in the UK, less than a fifth in France, and around a tenth in Germany and the Netherlands believed that RYO is healthier. Compared with exclusive FM users, exclusive RYO users were more likely to have lower incomes and lower education.

CONCLUSIONS

Effective tobacco tax regulation is needed in the European Union and elsewhere to eliminate or reduce the price advantage of RYO tobacco. Additional health messages are also required to correct the misperception that RYO tobacco is healthier than FM cigarettes.

Impulsivity and cigarette craving among adolescent daily and occasional smokers

INTRODUCTION

Impulsivity is a multi-dimensional construct that is robustly related to cigarette smoking. While underlying factors that account for this relation are not well understood, craving has been proposed as a central mechanism linking impulsivity to smoking. In order to further refine our understanding of associations between impulsivity and cigarette craving, the current study examined the association between impulsivity and tonic and cue-elicited craving among a sample of adolescent smokers. We expected trait impulsivity would be positively associated with both tonic and cue-elicited craving, and that this relationship would be stronger among daily vs. occasional smokers.

METHODS

106 smokers (ages 16-20) completed the questionnaires and reported their cigarette craving prior to and immediately following presentation of each of three counterbalanced cue types: (a) in vivo smoking, (b) alcohol, and (c) neutral cue.

RESULTS

Impulsivity was positively associated with tonic craving for daily smokers (β=.38; p=.005), but not occasional smokers (β=.01; p=.95), with a significant impulsivity x smoker group interaction (β=1.31; p=.03). Impulsivity was unrelated to craving following smoking or alcohol cue, regardless of smoker group (all p's>.16).

CONCLUSIONS

Results suggest a moderated effect in which impulsivity is positively associated with tonic craving for daily smokers, but not occasional smokers. Tonic craving may serve as a mechanism linking impulsivity, smoking persistence, and nicotine dependence among daily smokers.

The association between senior student tobacco use rate at school and alternative tobacco product use among junior students in Canadian secondary schools

Background

The use of alternative tobacco products (ATPs) has grown in popularity among Canadian youth. This study examined the association between a school-level characteristic (the senior student tobacco use rate) and the current use of manufactured cigarettes, little cigars or cigarillos, cigars, roll-your-own cigarettes, smokeless tobacco (SLT), and a hookah among junior students.

Methods

This study used nationally representative Canadian data from 29,495 students in grades 9 to 12 as part of the 2010/2011 Youth Smoking Survey. For each ATP, we described rates of senior and junior tobacco use, calculated the variance attributed to school-level factors, and examined the association between the senior student (grades 11 and 12) tobacco use rate and the current use of each ATP among junior students (grades 9 and 10) while accounting for relevant student-level characteristics. SAS 9.3 was used for all analyses.

Results

Over half of schools sampled had senior students that reported using each ATP. School-level differences accounted for between 14.1% and 29.7% of the variability in ATP current use among junior students. Each one percent increase in the number of senior students at a school that currently use manufactured cigarettes, SLT, or a hookah was significantly independently associated with an increased likelihood that a junior student at that school currently used manufactured cigarettes (OR 1.04, 95% CI 1.01 to 1.06), SLT (OR 1.14, 95% CI 1.06 to 1.24), or a hookah (OR 1.09, 95% CI 1.03 to 1.14).

Conclusions

Characteristics of the school environment a junior student attends appear to play an important role in ATP use, and tobacco control programs and policies should be designed to ensure that they include strategies to curb the use of all tobacco products. Additional evidence is needed for the impact of comprehensive school-based tobacco control approaches.

Dose-response relationship of lung cancer to amount smoked, duration and age starting

AIM: To quantify smoking/lung cancer relationships accurately using parametric modelling.

METHODS: Using the International Epidemiological Studies on Smoking and Lung Cancer database of all epidemiological studies of 100+ lung cancer cases published before 2000, we analyzed 97 blocks of data for amount smoked, 35 for duration of smoking, and 27 for age started. Pseudo-numbers of cases and controls (or at risk) estimated from RRs by dose level formed the data modelled. We fitted various models relating log_e RR to dose (d), including βd, βd^Y and βlog_e (1 + Wd), and investigated goodness-of-fit and heterogeneity between studies.

RESULTS: The best-fitting models for log_e RR were 0.833 log_e [1 + (8.1c/10)] for cigarettes/d (c), 0.792 (y/10)^0.74 for years smoked (y) and 0.176 [(70 - a)/10]^1.44 for age of start (a). Each model fitted well overall, though some blocks misfitted. RRs rose from 3.86 to 22.31 between c = 10 and 50, from 2.21 to 13.54 between y = 10 and 50, and from 3.66 to 8.94 between a = 30 and 12.5. Heterogeneity (P < 0.001) existed by continent for amount, RRs for 50 cigarettes/d being 7.23 (Asia), 26.36 (North America) and 22.16 (Europe). Little heterogeneity was seen for duration of smoking or age started.

CONCLUSION: The models describe the dose-relationships well, though may be biased by factors including misclassification of smoking status and dose.

Worldwide trend of increasing primary adenocarcinoma of the lung

The four major histological types of lung cancer are adenocarcinoma, squamous cell carcinoma (SQ), large cell carcinoma and small cell carcinoma. Over the past few decades, the incidence of lung adenocarcinoma has increased gradually in most countries as the most frequently occurring histological type, displacing SQ. Adenocarcinoma is the predominant type of lung cancer among lifelong non-smokers and among females. Especially in East Asian countries, the cause(s) of the increase in adenocarcinomas are not clear. Several genetic mutations specific to lung adenocarcinomas have been found, representing attractive targets for molecular therapy. Recently, the pathological classification of lung adenocarcinoma was revised by integrating the newer clinical and biological knowledge concerning this prevailing type. Additional epidemiological, pathological and genetic studies are required to better understand this type of lung cancer.

Make your own cigarettes: characteristics of the product and the consumer

INTRODUCTION

Despite a worldwide increase in the use of Make Your Own (MYO) cigarettes, there is little research characterizing MYO smokers in the United States and the cigarettes they make.

METHODS

In a single laboratory visit, exclusive MYO smokers brought 5 MYO cigarettes they prepared at home, completed demographic and smoking history questionnaires, and prepared 25 cigarettes using their own tobacco and materials.

RESULTS

Participants were mostly male (86.7%), average age of 41.3 years, and smoked an average of 19.5 (SD = 7.9) MYO cigarettes per day. They produced two types of cigarettes-by rolling tobacco in a paper leaf (Roll Your Own [RYO, n = 56]) and by injecting tobacco into a tube (Personal Machine Made [PMM, n = 42]). The PMM cigarettes were significantly larger than RYO cigarettes (p < .001). Home- (0.97 g) and laboratory-produced (0.95 g) PMM cigarettes did not differ by weight; however, the RYO cigarettes made at home (0.45 g) were slightly, but significantly, larger than those produced in the laboratory [0.43 g (p < .05)]. There was significant internal consistency in the weight of RYO and PMM cigarettes (intraclass correlation coefficient = 0.82, 0.84, respectively). Time to produce RYO cigarettes (53 s/cigarette) was significantly longer than that of PMM cigarettes (42 s/cigarette) (p < .01).

CONCLUSIONS

By using commercially available tobacco, tubes, and paper, experienced MYO smokers can quickly and consistently prepare cigarettes that may be useful in laboratory smoking topography and exposure experiments. Increasing the regulation of Factory Made (FM) cigarettes may lead to increased use of MYO cigarettes with unknown toxicant exposure and health risks to their consumers.

Retrospective cohort study of smoking and lung cancer incidence in rural prefecture, Japan

OBJECTIVES

We conducted an epidemiological study of the relationship between lung cancer incidence and smoking, with special reference to the benefits of smoking cessation for reducing lung cancer incidence, to promote a local smoking control program.

METHODS

The study was a retrospective cohort study. The population studied was 16,383 male examinees of lung cancer health examinations in 1995 in Tottori Prefecture, Japan. Smoking status from the questionnaire during the health examination was used as the exposure variable. Endpoint (lung cancer incidence) was obtained from the Tottori population-based cancer registry. A multivariable analysis using the Cox proportional hazard model was adapted for statistical analysis. The average follow-up period was 4.3 years.

RESULTS

The hazard ratio of current smokers for the incidence of lung cancer was 4.9, whereas that of ex-smokers was 2.2. The dose-response relationship between lung cancer incidence and lifetime cigarette consumption (pack year) was determined. The ratio increased among younger subjects (under 65 years old). The hazard ratio of ex-smokers decreased with years just after quitting smoking, and reached the level of never smokers after 10-19 years from smoking cessation.

CONCLUSIONS

We reconfirmed that the magnitude of risk estimates of smoking for lung cancer incidence was similar to those of previous studies, and smoking cessation was effective for reducing lung cancer risk.

Systematic review with meta-analysis of the epidemiological evidence in the 1900s relating smoking to lung cancer

BACKGROUND

Smoking is a known lung cancer cause, but no detailed quantitative systematic review exists. We summarize evidence for various indices.

METHODS

Papers published before 2000 describing epidemiological studies involving 100+ lung cancer cases were obtained from Medline and other sources. Studies were classified as principal, or subsidiary where cases overlapped with principal studies. Data were extracted on design, exposures, histological types and confounder adjustment. RRs/ORs and 95% CIs were extracted for ever, current and ex smoking of cigarettes, pipes and cigars and indices of cigarette type and dose-response. Meta-analyses and meta-regressions investigated how relationships varied by study and RR characteristics, mainly for outcomes exactly or closely equivalent to all lung cancer, squamous cell carcinoma ("squamous") and adenocarcinoma ("adeno").

RESULTS

287 studies (20 subsidiary) were identified. Although RR estimates were markedly heterogeneous, the meta-analyses demonstrated a relationship of smoking with lung cancer risk, clearly seen for ever smoking (random-effects RR 5.50, CI 5.07-5.96) current smoking (8.43, 7.63-9.31), ex smoking (4.30, 3.93-4.71) and pipe/cigar only smoking (2.92, 2.38-3.57). It was stronger for squamous (current smoking RR 16.91, 13.14-21.76) than adeno (4.21, 3.32-5.34), and evident in both sexes (RRs somewhat higher in males), all continents (RRs highest for North America and lowest for Asia, particularly China), and both study types (RRs higher for prospective studies). Relationships were somewhat stronger in later starting and larger studies. RR estimates were similar in cigarette only and mixed smokers, and similar in smokers of pipes/cigars only, pipes only and cigars only. Exceptionally no increase in adeno risk was seen for pipe/cigar only smokers (0.93, 0.62-1.40). RRs were unrelated to mentholation, and higher for non-filter and handrolled cigarettes. RRs increased with amount smoked, duration, earlier starting age, tar level and fraction smoked and decreased with time quit. Relationships were strongest for small and squamous cell, intermediate for large cell and weakest for adenocarcinoma. Covariate-adjustment little affected RR estimates.

CONCLUSIONS

The association of lung cancer with smoking is strong, evident for all lung cancer types, dose-related and insensitive to covariate-adjustment. This emphasises the causal nature of the relationship. Our results quantify the relationships more precisely than previously.

Cigarette Smoking and Lung Cancer: Pediatric Roots

A vast array of data suggests that early age of smoking onset enhances the risk for development of lung cancer in adulthood. Initiation of smoking at a young age may influence the development of lung cancer because of its effect on duration of smoking. Early onset of smoking also may serve as an independent risk factor. It may increase the likelihood that smoking occurs during a critical period of development that enhances susceptibility to the adverse effects of cancer causing agents in cigarette smoke, thereby facilitating the initiation of the carcinogenic process. While evidence for the latter hypothesis derives from a variety of sources, definitive proof has proven elusive. Whether or not early age of smoking serves as an independent risk factor for lung carcinogenesis, the consensus of the public health community is that prevention of smoking onset at a young age and early cessation are keys to stemming the current lung cancer pandemic. Population approaches to tobacco prevention and control, such as measures contained in the World Health Organization Framework Convention Tobacco Control Treaty, offer the best opportunity, on the scale needed, to create a smoke-free world and bring an end to the pandemic of tobacco-related disease.

Roll-your-own tobacco use among Canadian youth: is it a bigger problem than we think?

Background

Despite the apparent decline in the popularity of roll-your-own (RYO) cigarettes over the past few decades, RYO tobacco products are widely available and used by a substantial number of adult smokers. Considering research has yet to examine the prevalence of RYO tobacco use among youth populations, this manuscript examines the prevalence of RYO tobacco use and factors associated with RYO use in a nationally representative sample of youth smokers from Canada.

Methods

This study used data collected from 3,630 current smokers in grades 9 to 12 as part of the 2008-09 Canadian Youth Smoking Survey (YSS). Descriptive analyses of the sample demographic characteristics, smoking status, cigarettes per day, weekly spending money, and frequency of marijuana use were examined by RYO tobacco ever use and RYO tobacco current use. Two logistic regression models were used to examine factors associated with RYO tobacco ever use and RYO tobacco current use.

Results

We identified that 51.2% of current smokers were RYO ever users and 24.2% were RYO current users. The prevalence of RYO current users was highest in Atlantic Canada (40.1%) and lowest in Quebec (12.3%). RYO current users were more likely to be male (OR 1.27), to be daily smokers (OR 1.75), to use marijuana once a month or more (OR 2.74), and to smoke 11 or more cigarettes per day (OR 6.52). RYO current users were less likely to be in grade 11 (OR 0.65) or grade 12 (OR 0.40) and less likely to have between $20 to $100 (OR 0.44) or more than $100 (OR 0.45) of disposable income.

Conclusions

Developing a better understanding of RYO tobacco use among youth is important for advancing population-level tobacco control prevention strategies and cessation programs. We identified that RYO tobacco use is not a negligible problem among Canadian youth. Ongoing research is needed to continue monitoring the prevalence of RYO use among youth and the factors associated with its use, but to also monitor if this more affordable tobacco product is being targeted to price sensitive youth smokers.

Trends in roll-your-own smoking: findings from the ITC Four-Country Survey (2002-2008)

OBJECTIVE

To establish the trends in prevalence, and correlates, of roll-your-own (RYO) use in Canada, USA, UK and Australia, 2002-2008.

METHODS

Participants were 19,456 cigarette smokers interviewed during the longitudinal International Tobacco Control (ITC) Four-Country Survey in Canada, USA, UK, and Australia.

RESULTS

"Predominant" RYO use (i.e., >50% of cigarettes smoked) increased significantly in the UK and USA as a proportion of all cigarette use (both P < .001) and in all countries as a proportion of any RYO use (all P < .010). Younger, financially stressed smokers are disproportionately contributing to "some" use (i.e., ≤50% of cigarettes smoked). Relative cost was the major reason given for using RYO, and predominant RYO use is consistently and significantly associated with low income.

CONCLUSIONS

RYO market trends reflect the price advantages accruing to RYO (a product of favourable taxation regimes in some jurisdictions reinforced by the enhanced control over the amount of tobacco used), especially following the impact of the Global Financial Crisis; the availability of competing low-cost alternatives to RYO; accessibility of duty-free RYO tobacco; and tobacco industry niche marketing strategies. If policy makers want to ensure that the RYO option does not inhibit the fight to end the tobacco epidemic, especially amongst the disadvantaged, they need to reduce the price advantage, target additional health messages at (young) RYO users, and challenge niche marketing of RYO by the industry.

Tobacco-related tumours of the lung, bladder and larynx: changes in Spain

The association between tobacco use and lung cancer and other tumours has been confirmed by a large number of studies. In Spain, the prevalence of smoking has been declining since 1978. This study describes lung, bladder and laryngeal cancer mortality and incidence rates and their trends in Spain. Mortality data were furnished by the National Statistics Institute (2001-07) and incidence data by population-based cancer registries (1975-2004). Changes in rates were calculated using Poisson regression models, which enable trend changes to be estimated. In the case of lung cancer, mortality rates decreased among men [annual percentage change (APC) -1.3%] though not among women (APC 3.5%), whereas incidence rates increased in both sexes, overall and adjusted for registry, by 0.75% among men and 3.2% among women. Bladder cancer mortality rates decreased among men (APC -1.2%) and women (APC -0.8%), yet incidence rates increased across the sexes. While laryngeal cancer mortality rates decreased among men (APC -5.5%) and women (APC -0.03%) alike, incidence rates decreased (-1.28%) among men but not among women (3.95%). A decrease in male versus female mortality due to tobacco-related tumours is evident in Spain. Incidence rates are beginning to reflect the progressive cessation of smoking that has been observed among men rather than women.

Prevalence, correlates of, and reasons for using roll-your-own tobacco in a high RYO use country: findings from the ITC New Zealand survey

AIM

To describe the prevalence, correlates of, and reasons for use of roll-your-own (RYO) tobacco in a high RYO use and ethnically diverse country: New Zealand (NZ).

METHODS

The NZ arm of the International Tobacco Control Policy Evaluation Survey (ITC Project) is sampled from the New Zealand Health Survey, with boosted sampling of Māori, Pacific peoples, and Asian New Zealanders. We surveyed 1,376 current adult smokers using standard ITC project procedures in 2007-2008.

RESULTS

Prevalence of regularly smoking RYOs was 53% (with 38% of all smokers being exclusive RYO smokers). RYO use was higher among disadvantaged smokers, heavier smokers, those with a relatively low intention of quitting, and those with more friends who smoke. RYO use increased more in the youngest age groups as disadvantage increased. "Lower price" dominated the reasons smokers' cited for smoking RYOs (at 83%). About one fifth cited "less health concerns" as a reason.

CONCLUSIONS

RYO smoking is particularly associated with individual deprivation and high levels of dependence. Its capacity to blunt price signals provided by tobacco taxes is accompanied by misperceptions that it is less hazardous to health and it is particularly prevalent among vulnerable disadvantaged populations (including Māori, young people, and those with mental health problems). Governments should reconsider removing any tax advantages given to RYO tobacco, ensure RYO smokers are properly informed of health risks, and supported to quit as strongly as other smokers. However, governments should also examine a broader range of options including a higher differential tax on RYO tobacco, removing flavors, and controlling all tobacco marketing.

Educational inequalities in mortality over four decades in Norway: prospective study of middle aged men and women followed for cause specific mortality, 1960-2000

OBJECTIVES

To determine the extent to which educational inequalities in relation to mortality widened in Norway during 1960-2000 and which causes of death were the main drivers of this disparity.

DESIGN

Nationally representative prospective study.

SETTING

Four cohorts of the Norwegian population aged 45-64 years in 1960, 1970, 1980, and 1990 and followed up for mortality over 10 years.

PARTICIPANTS

359 547 deaths and 32 904 589 person years.

MAIN OUTCOME MEASURES

All cause mortality and deaths due to cancer of lung, trachea, or bronchus; other cancer; cardiovascular diseases; suicide; external causes; chronic lower respiratory tract diseases; or other causes. Absolute and relative indices of inequality were used to present differences in mortality by educational level (basic, secondary, and tertiary).

RESULTS

Mortality fell from the 1960s to the 1990s in all educational groups. At the same time the proportion of adults in the basic education group, with the highest mortality, decreased substantially. As mortality dropped more among those with the highest level of education, inequalities widened. Absolute inequalities in mortality denoting deaths among the basic education groups minus deaths among the high education groups doubled in men and increased by a third in women. This is equivalent to an increase in the slope index of inequality of 105% in men and 32% in women. Inequalities on a relative scale widened more, from 1.33 to 2.24 among men (P=0.01) and from 1.52 to 2.19 among women (P=0.05). Among men, absolute inequalities mainly increased as a result of cardiovascular diseases, lung cancer, and chronic lower respiratory tract diseases. Among women this was mainly due to lung cancer and chronic lower respiratory tract diseases. Unlike the situation in men, absolute inequalities in deaths due to cardiovascular causes narrowed among women. Chronic lower respiratory tract diseases contributed more to the disparities in inequalities among women than among men.

CONCLUSION

All educational groups showed a decline in mortality. Nevertheless, and despite the fact that the Norwegian welfare model is based on an egalitarian ideology, educational inequalities in mortality among middle aged people in Norway are substantial and increased during 1960-2000.

Smoking trajectories, health, and mortality across the adult lifespan

This study extends research on the association between smoking behavior and chronic disease by following a cohort from the time of initiation of regular smoking patterns into old age and by examining the association of lifetime smoking trajectories with chronic disease and mortality. Participants consisted of 232 males selected from the Harvard classes of 1942-1944 and followed biennially through 2003. Five distinct smoking trajectories were identified based on the age at which participants quit daily smoking. Participants following smoking trajectories with later cessation had a higher likelihood of developing lung disease and lived shorter lives than those who quit smoking at an earlier age. This study confirms that the earlier a smoker quits, the greater the health benefits, and that these benefits are observed even decades after smoking cessation. Additionally, by showing different survival rates between trajectory groups 25 and 40 years after quitting, the results run counter to previous work that has found no difference in mortality between smokers and non-smokers 15 years after cessation.

A comparison of exposure to carcinogens among roll-your-own and factory-made cigarette smokers

Consumption of roll-your-own (RYO) tobacco is rising, but little is known about its in vivo delivery of toxins relative to factory-made (FM) cigarettes. To start to address this issue, this study compared the concentrations of metabolites of recognized human carcinogens in smokers of RYO tobacco and FM cigarettes. We opportunistically recruited 127 FM and 28 RYO cigarette smokers in central London and collected saliva and urine samples. Saliva samples were assayed for cotinine while urinary samples were assayed for 1-hydroxypyrene (1-HOP) and total 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), metabolic markers of polycyclic aromatic hydrocarbons and tobacco-specific N-nitrosamines, respectively. Data on socio-demographic, anthropometric and puffing characteristics were also obtained. Both unadjusted and adjusted analyses (controlling for age, sex, body mass index, puff flow, puff duration and cotinine) showed no difference in metabolic markers between RYO and FM cigarette smokers. However, significant main effects for cotinine levels and sex were observed in adjusted analyses. Greater levels of cotinine were associated with a greater concentration of both 1-HOP (B = 0.002, P = 0.037) and NNAL (B = 0.002, P < 0.001). In addition, women had significantly greater concentrations of urinary 1-HOP (B = 0.679, P = 0.004) and total NNAL metabolites (B = 0.117, P = 0.024) than men, irrespective of the type of cigarettes smoked. More research is now needed to confirm these findings and gender-specific effects in a larger, representative sample. However, results do not support the common belief that RYO cigarettes are less harmful than manufactured cigarettes.

Relationships between hand-rolled cigarettes and primary lung cancer: a Norwegian experience

INTRODUCTION

Detailed smoking history of patients developing lung cancer is rarely known, especially not for users of hand-rolled cigarettes. In Norway, smoking hand-rolled tobacco is still popular, accounting for one-third of the total tobacco consume.

METHODS

A questionnaire-based study revealing detailed information about tobacco consume with consecutive inclusion of all persons developing lung cancer in Southern Norway 2002-2005.

RESULTS

In this unselected population with 479 patients with newly diagnosed lung cancer, 95% had a smoking history and 88% of ever-smokers had smoked primarily hand-rolled cigarettes. The hand-rolled cigarette smokers had smoked fewer cigarettes daily (15) and less pack-years of tobacco (34) than fabricated cigarette smokers (20, P < 0.0001 and 42, P = 0.021, respectively). Smoking hand-rolled cigarettes was considerably more frequent than expected from official sales statistics. Hand-rolled cigarette smoking revealed an odds ratio of 13 for developing lung cancer compared with smoking fabricated cigarettes.

CONCLUSION

In this unselected population with newly diagnosed lung cancer, nine out of 10 ever-smokers had smoked primarily hand-rolled cigarettes. Patients smoking hand-rolled cigarettes had a smoking history of fewer daily cigarettes and less pack-years tobacco consumed than fabricated cigarette smokers. In this study, hand-rolled cigarettes are more frequently used than shown in national statistics. Smokers of hand-rolled cigarettes may have a greatly increased risk for lung cancer compared with smokers of fabricated cigarettes.

Hand-rolled cigarette smoking patterns compared with factory-made cigarette smoking in New Zealand men

BACKGROUND

Roll-your-own (RYO) cigarettes have increased in popularity, yet their comparative potential toxicity is uncertain. This study compares smoking of RYO and factory-made (FM) cigarettes on smoking pattern and immediate potential toxicity.

METHODS

At a research clinic, 26 RYO and 22 FM volunteer male cigarette smokers, (addicted and overnight-tobacco-abstinent) each smoked 4 filter cigarettes, one half-hourly over 2 hours, either RYO or FM according to usual habit, using the CReSSMicro flowmeter. First cigarette smoked was their own brand. Subsequent cigarettes, all Holiday regular brand, were RYOs (0.5 g tobacco with filter), or FM with filter. Cravings on 100 mm visual analogue scale, and exhaled carbon monoxide (CO) were measured before and after each cigarette smoked.

RESULTS

Smokers reported similar daily cigarette consumption (RYO 19.0, FM 17.4, p = 0.45), and similar time after waking to first cigarette. (RYO 6.1 minutes, FM 8.6 minutes, p = 0.113). First cigarette's RYO tobacco (0.45 g) weighed less than for FM (0.7 g, p < 0.001); less tobacco was burnt (0.36 g, FM 0.55 g, p < 0.001) but smoking patterns were no different. RYO smokers smoked subsequent cigarettes more intensively; inhaled 28% more smoke per cigarette (RYO 952 mL, FM 743 mL, p = 0.025); took 25% more puffs (RYO 16.9, FM 13.6, p = 0.035); puffed longer (RYO 28 seconds, FM 22 seconds, p = 0.012), taking similar puffs (RYO 57 mL, FM 59 mL). Over four cigarettes, RYOs boosted alveolar CO (RYO 13.8 ppm, FM 13.8 ppm), and reduced cravings (RYO 53%, FM 52%) no differently from FM cigarettes.

CONCLUSION

In these smokers, RYO smoking was associated with increased smoke exposure per cigarette, and similar CO breath levels, and even with filters is apparently no less and possibly more dangerous than FM smoking. Specific package warnings should warn of RYO smoking's true risk. RYOs are currently taxed much less than FM cigarettes in most countries; similar harm merits similar excise per cigarette.

Cigarettes butts and the case for an environmental policy on hazardous cigarette waste

Discarded cigarette butts are a form of non-biodegradable litter. Carried as runoff from streets to drains, to rivers, and ultimately to the ocean and its beaches, cigarette filters are the single most collected item in international beach cleanups each year. They are an environmental blight on streets, sidewalks, and other open areas. Rather than being a protective health device, cigarette filters are primarily a marketing tool to help sell 'safe' cigarettes. They are perceived by much of the public (especially current smokers) to reduce the health risks of smoking through technology. Filters have reduced the machine-measured yield of tar and nicotine from burning cigarettes, but there is controversy as to whether this has correspondingly reduced the disease burden of smoking to the population. Filters actually may serve to sustain smoking by making it seem less urgent for smokers to quit and easier for children to initiate smoking because of reduced irritation from early experimentation. Several options are available to reduce the environmental impact of cigarette butt waste, including developing biodegradable filters, increasing fines and penalties for littering butts, monetary deposits on filters, increasing availability of butt receptacles, and expanded public education. It may even be possible to ban the sale of filtered cigarettes altogether on the basis of their adverse environmental impact. This option may be attractive in coastal regions where beaches accumulate butt waste and where smoking indoors is increasingly prohibited. Additional research is needed on the various policy options, including behavioral research on the impact of banning the sale of filtered cigarettes altogether.

The roll-your-own cigarette market in Canada: a cross-sectional exploratory study

Background

Even though the use and prevalence of roll-your-own cigarettes (RYO) has been declining over the past decades, RYO remains important. Given the paucity of research examining RYO use, there is a need to better understand the current and potential future context of RYO use.

Methods

Data from the 2002 Canadian Tobacco Use Monitoring Survey (CTUMS) were used to examine RYO tobacco use among 23,341 Canadians aged 15 and older. Logistic regression models were conducted to examine factors which differentiate smokers who smoke RYO tobacco all of the time, most of the time or sometimes from smokers who do not smoke RYO tobacco.

Results

We found that 17% (n = 925,000) of current smokers in Canada reported smoking RYO. When compared to manufactured cigarette (MC) smokers, RYO users were heavier smokers, more addicted to nicotine, and less likely to consider quitting smoking. Lower income smokers were more likely to smoke RYO tobacco compared to smokers with high income. Conversely, smokers who had completed secondary school or university were less likely to smoke RYO tobacco compared to smokers who had not completed secondary school.

Conclusion

This study demonstrates that RYO tobacco use is not a negligible problem within Canada and provides valuable new insight for developing future tobacco control initiatives for this population of smokers.

Predicting lung cancer death in Africa and Asia: differences with WHO estimates

OBJECTIVE

Reliable cancer burden estimates are rarely available from most developing countries where cancer registration is lacking. This study provided estimates on the current and future number of lung cancer deaths in Indonesia, Vietnam and Ethiopia, and Sub-Saharan Africa at large.

METHODS

The number of lung cancer deaths was estimated from detailed smoking prevalence data (obtained from surveys among 8,726 rural individuals aged 25-74 years in Indonesia, Vietnam, and Ethiopia in 2005-2006) and on lung cancer rate estimates among non-smokers.

RESULTS

Our estimate for lung cancer deaths in Sub-Saharan Africa is 44,076 in 2005, which is 2.6 times the most recent WHO estimate in 2003 (17,000 deaths). A similar ratio is found for the country-specific estimate in Ethiopia. Our estimates are only slightly higher than the WHO's in Indonesia, and Vietnam. The attributable risk of smoking for lung cancer death among men was 39% in Ethiopia, 80% in Indonesia and 85% in Vietnam. We expect the annual number of lung cancer deaths to double by 2025, even if the smoking prevalence is assumed not to increase further.

CONCLUSIONS

WHO estimates on lung cancer deaths in Asia appear to be slightly lower than our study results; however, in Africa, the burden appears to be largely underestimated.

Autofluorescence bronchoscopy in volunteer asymptomatic smokers

We assess the sensitivity of autofluorescence bronchoscopy (AFB) compared to that of white light bronchoscopy (WLB) for identification of pre-invasive neoplastic changes of bronchial mucosa in asymptomatic heavy smokers. WLB was performed using a standard flexible fibre-optic bronchoscope, and AFB carried out using the Xillix LIFE Lung((R)) system. Positive AFB images were indicated in the bronchial tree from 51 of the 93 subjects in the study. Biopsies showed epithelial abnormalities in 27 (15 metaplasia, 12 inflammatory changes) of these. WLB showed abnormality in 1 subject but with no pathological changes revealed by cyto-histology. Therefore, the sensitivity of AFB to metaplasia was 75% compared to zero for WLB. AFB yields positive predictive values for metaplastic and overall mucosal changes of 29.4% and 52.9%, respectively. In summary, over 16% of asymptomatic smokers had metaplastic changes in their bronchial mucosa, and AFB proved more sensitive in revealing early changes than WLB.

Cancer incidence in patients with schizophrenia and their first-degree relatives - a meta-analysis

OBJECTIVE

Controversy concerning cancer incidence in schizophrenia exists because of heterogeneous study findings.

METHOD

A meta-analysis was performed on standardized incidence ratios (SIR) of cancer in patients with schizophrenia and first-degree relatives and compared with general population samples.

RESULTS

The pooled overall cancer incidence in patients was not significantly increased (SIR = 1.05, CI 0.95-1.15). Lung cancer incidence was slightly increased (SIR = 1.31, CI 1.01-1.71), but was reduced after adjusting for smoking prevalence. The incidence of several cancers unrelated to smoking was reduced in patients. Breast cancer rates were significantly increased in female patients. The pooled overall cancer incidence in siblings (SIR = 0.89, CI 0.84-0.94) and parents (SIR = 0.90, CI 0.88-0.93) was significantly reduced. A meta-regression detected a significant relationship between cancer risk in the general population and relative risk in patients.

CONCLUSION

The meta-analysis aided exploration of inconsistent study findings. There is a discrepancy between cancer risk exposure and cancer incidence in schizophrenia consistent with a protective effect.

Comparison of aspects of smoking among the four histological types of lung cancer

BACKGROUND

The magnitude of the link between cigarette smoking and lung cancer may vary by histological type.

METHODS

We used polytomous logistic regression to evaluate whether aspects of smoking have different effects across four histological types in the Nurses' Health Study.

RESULTS

From 1976 to 2002, we identified 1062 cases of lung cancer: squamous cell (n = 201), small cell (n = 236), adenocarcinoma (n = 543) and large cell carcinoma (n = 82), among 65 560 current or former smokers. Risk reduction after quitting ranged from an 8% reduction (relative risk (RR): 0.92, 95% CI 0.91 to 0.94) to a 17% reduction (RR: 0.83, 95% CI 0.80 to 0.86) per year for adenocarcinoma and small cell carcinoma, respectively, with a 9% reduction observed for large cell carcinoma and an 11% reduction observed for squamous cell carcinoma. The association of age at smoking initiation and former cigarette smoking was similar across types, while the association of smoking duration differed. The risk of adenocarcinoma increased by 6% per year of smoking, compared to 7% for large cell, 10% for squamous cell and 12% for small cell. The 6% difference between adenocarcinoma and small cell carcinoma is equivalent to a 3.2 to 9.7-fold increase in risk for 20 years of smoking.

CONCLUSIONS

The effects of the number of cigarettes smoked per day and years since quitting smoking are different across the major types of lung cancer, which are fully appreciated at long durations of smoking and smoking cessation. Smoking prevention and cessation should continue to be the focus of public health efforts to reduce lung cancer incidence and mortality.

Reproductive factors and pancreatic cancer risk: a Norwegian cohort study

A cohort of 63 090 Norwegian women born 1886–1928 was followed more than 38 years, and relations between reproductive factors and risk of pancreatic cancer were explored; 449 cases were recorded at ages 50–89 years. Age at menopause showed a moderately positive association with risk (rate ratio (RR)=1.08 per 2 years delay in menopause; 95% confidence interval (CI)=1.00–1.17). Neither parity nor duration of breastfeeding showed significant associations with risk after adjusting only for demographic factors. With mutual adjustment, however, parity became positively associated (RR=1.13 per delivery; 95% CI=1.05–1.22) while duration of breastfeeding was inversely associated (RR=0.87 per 12 months; 95% CI=0.78–0.97). These associations lessened in magnitude with increasing age, and were essentially absent above age 80 years. Risk was raised among women reporting at least one abortion, but no trend was seen with number of abortions. Together with previous studies, the findings raise questions about the role of chance, but do not exclude hormonal factors related to breastfeeding and pregnancy from affecting pancreatic cancer risk.

Caractéristiques des adolescents fumeurs s'adressant aux consultations de tabacologie

In France, the prevalence of tobacco consumption is 31% for teenagers between 15 and 19 years old. Nevertheless, few French studies have been published on the characteristics of young smokers seeking smoking cessation services. The development of smoking cessation centres in France since 1999 was associated to the setting up of a e-transfer system in order to evaluate the adequacy between these services and the needs of smokers.

OBJECTIVE

To analyse the characteristics of smokers aged less than 19 years registered in the smoking cessation services national database.

METHODS

A cross-sectional population-based study has been conducted in the smoking cessation services participating in the national database. The study population included 321 young smokers attending the smoking cessation centres during the period 2001-2005.

RESULTS

The 321 smokers (mean age 16.6 years) were mostly girls (56.4%). A background of depression was declared by 19% of young smokers and an abnormal result was found for the hospital anxiety depression-screening test among 34% of the population for the anxiety scale and 6% for the depression scale. Mean daily tobacco consumption was 15.3 cigarettes per day and heavy nicotine dependence was found for 24.1% of the population. A nicotine replacement therapy was prescribed for every smoker.

CONCLUSION

Nicotine dependence was heavy for 24.1% of the 321 young smokers seeking smoking cessation services. More than 1/3 had an abnormal result for the hospital anxiety depression-screening test. Tailored interventions for smoking cessation should be available for adolescent's smokers, especially school-based services.

Non-steroidal anti-inflammatory drugs and the risk of oral cancer: a nested case-control study

BACKGROUND

Non-steroidal anti-inflammatory drugs (NSAIDs) seem to prevent several types of cancer, but could increase the risk of cardiovascular complications. We investigated whether use of NSAIDs was associated with a change in the incidence of oral cancer or overall or cardiovascular mortality.

METHODS

We undertook a nested case-control study to analyse data from a population-based database (Cohort of Norway; CONOR), which consisted of prospectively obtained health data from all regions of Norway. People with oral cancer were identified from the 9241 individuals in CONOR who were at increased risk of oral cancer because of heavy smoking (15 pack-years), and matched controls were selected from the remaining heavy smokers (who did not have cancer).

FINDINGS

We identified and analysed 454 (5%) people with oral cancer (279 men, 175 women, mean [SD] age at diagnosis 63.3 [13.2] years) and 454 matched controls (n=908); 263 (29%) had used NSAIDs, 83 (9%) had used paracetamol (for a minimum of 6 months), and 562 (62%) had used neither drug. NSAID use (but not paracetamol use) was associated with a reduced risk of oral cancer (including in active smokers; hazard ratio 0.47, 95% CI 0.37-0.60, p<0.0001). Smoking cessation also lowered the risk of oral cancer (0.41, 0.32-0.52, p<0.0001). Additionally, long-term use of NSAIDs (but not paracetamol) was associated with an increased risk of cardiovascular-disease-related death (2.06, 1.34-3.18, p=0.001). NSAID use did not significantly reduce overall mortality (p=0.17).

INTERPRETATION

Long-term use of NSAIDs is associated with a reduced incidence of oral cancer (including in active smokers), but also with an increased risk of death due to cardiovascular disease. These findings highlight the need for a careful risk-benefit analysis when the long-term use of NSAIDs is considered.

Squamous and small cell carcinomas of the lung: similarities and differences concerning the role of tobacco smoking

In the time period 1988-2000, a case-case study on environmental factors and lung cancer risk was conducted in Montevideo, Uruguay. This study was designed in order the establish possible differences between squamous cell carcinomas (SCC) and small cell carcinomas (SCLC) of the lung in relation to tobacco smoking. Three hundred and ninety one (391) patients with small cell carcinoma were compared with 1187 patients with squamous cell carcinoma. Regarding sex, the study included a small number of women (26 with SCLC and 20 with SCC). SCLC was associated with higher risks for smoking status, smoking intensity and cumulative exposure to tobacco smoking when compared with SCC. These three tobacco variables were significantly different between both cell types in men. Smoking duration was significantly higher among SCLC compared with SCC only in women. With decreasing age at starting to smoke, the proportion of SCLC increases at the expense of SCC. Finally, types of tobacco and cigarette were not different between cell types in both sexes. It should be noted that these tobacco variables were not associated with increased risks among SCC, when this cell type was compared with SCLC. These results suggests that SCLC display the strongest relation with tobacco smoking than SCC.

Does increased cigarette consumption nullify any reduction in lung cancer risk associated with low-tar filter cigarettes?

Epidemiological data suggest that smoking filter and lower tar cigarettes is associated with less lung cancer risk than is smoking plain and higher tar cigarettes. A recent National Cancer Institute monograph claimed these apparent benefits of lower delivery products may be illusory if relative risks are adjusted for daily consumption, and switching leads to "compensation" for reduced nicotine intake by increasing numbers of cigarettes smoked. To investigate this, we compared relative risks unadjusted and adjusted for daily cigarette consumption. Overall estimates of the filter/plain relative risk, using random-effects meta-analysis, were 0.61 (95%confidence interval 0.54 to 0.70) for unadjusted data and 0.66 (0.58 to 0.76) for adjusted data. The lower tar/higher tar relative risk was estimated as 0.60 (0.45 to 0.81) for unadjusted data and 0.73 (0.64 to 0.83) for adjusted data. The risk reductions were clearly seen regardless of gender, study location, period, or design, and when only studies providing both unadjusted and adjusted estimates were considered. Whether or not relative risk estimates are adjusted for cigarette consumption is not crucial to the conclusion of a clear advantage to filter cigarettes and tar reduction. Data on "compensation" for amount smoked were reviewed and any increase following switching to reduced-tar-yield cigarettes was shown to be quite small. Other biases in the epidemiology are also discussed, and we conclude that the apparent advantage to reduced-tar-delivery products is real and likely to be a marked underestimate of the reduction in lung cancer risk from lifetime smoking of low-tar cigarettes.

A flexible modeling approach to estimating the component effects of smoking behavior on lung cancer

OBJECTIVE

Despite the established causal association between cigarette smoking and lung cancer, the relative contributions of age started, duration, years since quitting, and daily amount smoked have not been well characterized. We estimated the contribution of each of these aspects of smoking behavior.

STUDY DESIGN AND SETTING

A case-control study was conducted in Montreal on the etiology of lung cancer. There were 640 cases and 938 control subjects for whom lifetime smoking histories were collected. We used generalized additive models, incorporating cubic smoothing splines to model nonlinear effects of various smoking variables. We adopted a multistep approach to deal with the multicollinearity among time-related variables.

RESULTS

The main findings are that (1) risk increases independently by daily amount and by duration; (2) among current smokers, lung cancer risk doubles for every 10 cigarettes per day up to 30 to 40 cigarettes per day and tails off thereafter; (3) among ex-smokers, the odds ratio decreases with increasing time since quitting, the rate of decrease being sharper among heavy smokers than among light smokers; and (4) absolute risks demonstrate the dramatic public health benefits of long-term smoking cessation.

CONCLUSION

Our results reinforce some previous findings on this issue.

Cigarette tar yields in relation to mortality from lung cancer in the cancer prevention study II prospective cohort, 1982-8

OBJECTIVE

To assess the risk of lung cancer in smokers of medium tar filter cigarettes compared with smokers of low tar and very low tar filter cigarettes.

DESIGN

Analysis of the association between the tar rating of the brand of cigarette smoked in 1982 and mortality from lung cancer over the next six years. Multivariate proportional hazards analyses used to assess hazard ratios, with adjustment for age at enrollment, race, educational level, marital status, blue collar employment, occupational exposure to asbestos, intake of vegetables, citrus fruits, and vitamins, and, in analyses of current and former smokers, for age when they started to smoke and number of cigarettes smoked per day.

SETTING

Cancer prevention study II (CPS-II).

PARTICIPANTS

364 239 men and 576 535 women, aged > or = 30 years, who had either never smoked, were former smokers, or were currently smoking a specific brand of cigarette when they were enrolled in the cancer prevention study.

MAIN OUTCOME MEASURE

Death from primary cancer of the lung among participants who had never smoked, former smokers, smokers of very low tar (< or = 7 mg tar/cigarette) filter, low tar (8-14 mg) filter, high tar (> or = 22 mg) non-filter brands and medium tar conventional filter brands (15-21 mg).

RESULTS

Irrespective of the tar level of their current brand, all current smokers had a far greater risk of lung cancer than people who had stopped smoking or had never smoked. Compared with smokers of medium tar (15-21 mg) filter cigarettes, risk was higher among men and women who smoked high tar (> or = 22 mg) non-filter brands (hazard ratio 1.44, 95% confidence interval 1.20 to 1.73, and 1.64, 1.26 to 2.15, respectively). There was no difference in risk among men who smoked brands rated as very low tar (1.17, 0.95 to 1.45) or low tar (1.02, 0.90 to 1.16) compared with those who smoked medium tar brands. The same was seen for women (0.98, 0.80 to 1.21, and 0.95, 0.82 to 1.11, respectively).

CONCLUSION

The increase in lung cancer risk is similar in people who smoke medium tar cigarettes (15-21 mg), low tar cigarettes (8-14 mg), or very low tar cigarettes (< or = 7 mg). Men and women who smoke non-filtered cigarettes with tar ratings > or = 22 mg have an even higher risk of lung cancer.

Cancer Incidence Profiles in the Miyagi Cohort Study

BACKGROUND

There were few prospective cohort studies in Japan using cancer incidence as an endpoint.

METHODS

We conducted a baseline survey with two self-administered questionnaires regarding lifestyle and personality on the residents aged 40 to 64 years in 14 municipalities of Miyagi Prefecture, Japan, during June through August, 1990. Out of the eligible 51,921 residents, 47,605 (91.7%) responded to the lifestyle questionnaire and formed the cohort under study. We collated the list of subjects in the cohort with the Miyagi Prefectural Cancer Registry data through December 31, 1997. To identify the same person between two data, we used four personal characteristics (sex, name, birthday, and municipality of dwelling).

RESULTS

We ascertained 1,718 cases of incident cancer. In men, gastric cancer was the leading site of cancer (27.7%), followed by lung cancer and colon cancer. In women, breast cancer was the most common (19.6%), followed by gastric cancer and colon cancer.

CONCLUSIONS

By record linkage with regional cancer registry data, it becomes possible for us to investigate the effect of various life-styles on cancer incidence in the Miyagi Cohort Study. We expect this data to contribute to the progress of research on cancer etiology and cancer prevention.

Lung cancer mortality patterns in selected Central, Eastern and Southern European countries

Significant changes in the prevalence of tobacco smoking have been observed in many European countries. EU candidate countries have also experienced major changes with respect to tobacco smoking, which have resulted in changes in the frequency of lung cancer. In men in the majority of these countries, a reduction of mortality rates has been observed recently, while in Hungary and Poland a deceleration of mortality increase was observed in the 1990s. The situation is much less favorable in females, where in the majority of countries a continuous increase of mortality rates has been observed, the only exceptions being Latvia, Lithuania and, to a lesser extent, Estonia. In Hungarian women, an acceleration of the increase rate was observed in the 1980s and 1990s (compared with the 1970s). Patterns of lung cancer mortality in analyzed countries are somewhat similar to those observed in EU member states. Recent analyses of time trends of lung cancer in EU countries showed, in general, a decreasing risk in the majority of male populations and an increase in several countries in women. If the decrease of mortality is to be achieved and maintained in the longer term, efforts have to be focused on young generations (entering adulthood now or in the near future). Despite all the difficulties present in reducing tobacco smoking in youth, it seems that one of the most important ways to reduce the future lung cancer burden in current and new EU member states is to strengthen efforts toward changing smoking attitudes in young generations.

Pipe and cigar smoking and major cardiovascular events, cancer incidence and all-cause mortality in middle-aged British men

BACKGROUND

Pipe and cigar smoking are still regarded by many as less hazardous to health than cigarette smoking.

METHODS

Prospective study of 7735 men aged 40-59 years drawn from general practices in 24 British towns with mean follow-up of 21.8 years. The outcome measures include major coronary heart disease (CHD) and stroke events, cancer incidence, and deaths from all causes.

RESULTS

There were 1133 major CHD events and 440 stroke events, 919 new cancers and 1994 deaths from all causes in the 7121 men with no diagnosed CHD, stroke, diabetes, or cancer at screening. Compared with never smokers, pipe/cigar smokers (primary and secondary combined) showed significantly higher risk of major CHD events (relative risk [RR] = 1.69, 95% CI: 1.32, 2.14) and stroke events (RR = 1.62, 95% CI: 1.08, 2.41) and of cardiovascular, non-cardiovascular, and total mortality (RR = 1.49, 95% CI: 1.13, 1.96, RR = 1.40, 95% CI: 1.08, 1.83 and RR = 1.44, 95% CI: 1.19, 1.74, respectively), after adjustment for lifestyle and biological characteristics. They also showed a significantly higher incidence of smoking-related cancers (RR = 2.67, 95% CI: 1.70, 4.26), largely due to lung cancer (RR = 4.35, 95% CI: 2.05, 8.94). Overall, the effects in pipe/cigar smokers were intermediate between never-smokers and light cigarette smokers, although risks for lung cancer were similar to light cigarette smokers.

CONCLUSION

Pipe and cigar smoking, whether primary or secondary, carries significant risk of smoking-related ill health.