Smoking, snus use and risk of right- and left-sided colon, rectal and anal cancer: a 37-year follow-up study

A systematic review of cancer risk among users of smokeless tobacco (Swedish snus) exclusively, compared with no use of tobacco

The main objective of this systematic review was to assess cancer risk, and mortality after cancer diagnosis, for exclusive users of Swedish snus, compared with non-users of tobacco. We followed international standards for systematic reviews and graded our confidence in the risk estimates using the GRADE approach. Our search gave 2450 articles, of which 67 were assessed in full text against our inclusion criteria. Of these, 14 cohort-studies and one case-control study were included in the review. The studies investigated risk of cancer in the oral cavity or oropharynx (3 studies), esophagus (1 study), stomach (1 study), pancreas (2 studies), colorectum (2 studies), anus (1 study) and lung (1 study), as well as malignant lymphoma (1 study), leukemia and multiple myeloma (1 study), melanoma (1 study), any cancer (1 study) and mortality after cancer diagnosis (4 studies). Cancer risk could only be evaluated in men as there was a general lack of data for women. All included studies were evaluated to have a moderate risk of bias, mostly related to validity of exposure information. An increased risk of cancer of the esophagus, pancreas, stomach and rectum as well as an association between use of snus and increased mortality after a cancer diagnosis was reported. Our confidence in the various risk estimates varied from moderate through low to very low.

Anal squamous cell carcinoma: standards of care, new data and ongoing clinical trials

PURPOSE OF REVIEW

To summarize current standards of care, discuss results of recent studies and present ongoing clinical trials for anal squamous cell carcinoma (ASCC).

RECENT FINDINGS

Over the last year, no practice changing studies have been reported in the setting of localised ASCC. A number of retrospective analyses, however, have provided practice-informing data, such as those confirming the negative impact of low compliance to chemoradiotherapy (CRT) on patient outcomes. In contrast, and for the first time, randomized evidence has become available to inform the management of advanced tumours. The InterAACT trial represents a key milestone in the evidence-building process for this disease, establishing carboplatin plus paclitaxel as a new standard of care for treatment-naïve advanced ASCC patients. Furthermore, more data have accumulated about the value of triplet chemotherapy in the first-line setting and of immune checkpoint inhibitors (either as single agents or in combination with other agents) in the refractory setting.

SUMMARY

Recent findings have the potential to improve the treatment quality standards and overall outcome of patients with either localised or advanced ASCC. Results from ongoing clinical trials will hopefully provide useful insights into the management of this disease and further shape current treatment paradigms.

How do former smokers perceive information about nicotine products? Evidence from Sweden

Purpose

Health promotion strategies often attempt to change people’s behavior through targeting their risk perceptions. These perceptions may, however, be moderated by other factors. This study therefore aimed at investigating the trustworthiness and consistency of risk information, as well as respondent perceptions of the adequacy of amount received among a representative sample of former smokers, and how this information is related to gender, age, education level and whether using nicotine or not.

Design/methodology/approach

The respondents are part of a seven-year follow-up of former smokers in Sweden. Initially, 1400 respondents were contacted, whereof 705 (response rate 50%) answered a Web-survey. The majority (85 %) was still nicotine-free but some made use of nicotine in different forms. The data analysis includes descriptive statistics and logistic regressions.

Findings

Most respondents trusted risk information whether offered by the public authorities or came from other sources such as media, and generally perceived that there was an adequate amount. However, there were some differences between the products, where quite a few distrusted information on Nicotine Replacement Therapies (NRTs) and some perceived the information on snus and NRTs as contradictory and too little.

Originality/value

Knowledge about how former smokers perceive information regarding negative aspects of cigarette use may facilitate more effective risk communication with current smokers, and it may also be important for communicating information about other nicotine products to those who are trying to or who already have quit smoking.

A 2020 update of anal cancer: the increasing problem in women and expanding treatment landscape

INTRODUCTION

Anal cancer is a rare malignancy with increasing incidence, notably in women. This disease is highly associated with HPV infection and its incidence and mortality are currently rising. Most patients present with localized disease which has a high survival after definitive treatment with chemoradiation. For patients who develop metastatic disease or present with this de novo, survival is poor.

AREAS COVERED

This review provides a summary of current literature on anal cancer. With a focus on women, this includes current epidemiological trends, role of HPV, and the current and future treatment landscape, including HPV vaccination and immunotherapy. Screening currently focusses on HIV-positive men, missing most female cases. In curative disease, trials are investigating treatment de-intensification in good prognostic groups. Immunotherapy is showing early promise in the advanced disease setting.

EXPERT OPINION

Similar to cervical cancer, anal cancer is strongly associated with HPV, and therefore, broader implementation of screening programs may reduce its incidence. HPV vaccination is expected to reduce the development of (pre)malignant anal lesions. The emergence of biomarkers will assist patient treatment selection, allowing optimal balance of treatment efficacy and morbidity. It is hoped that new treatment approaches, including immunotherapy, will improve outcomes. International collaboration is needed.

Mortality among male smokers and smokeless tobacco users in the USA

BACKGROUND

One published study simultaneously reported the mortality associated with cigarette smoking and smokeless tobacco (ST) use in the USA. In this study, we focus only on men ages 40-79 years old and extend the follow-up by 4 years.

METHODS

We used selected years (1987-2010) of National Health Interview Survey (NHIS) Linked Mortality Files to classify 46,104 men age 40-79 years with respect to 7 categories of smoking and/or ST use. We used Cox proportional hazards models adjusted for age, race/ethnicity, marital status, education, income, health status, body mass index, and region to estimate hazard ratios (HRs; 95% confidence intervals, CI) for mortality from all causes, heart diseases, malignant neoplasms, and two mutually exclusive categories: smoking-related and other diseases.

RESULTS

There were 15,540 deaths from all causes, including 3476 never tobacco users, 4782 exclusive smokers, and 210 exclusive ST users. The latter had significant excess mortality from all causes (HR = 1.25, CI = 1.08-1.46), but not from heart diseases (HR = 1.16, CI = 0.85-1.59), malignant neoplasms (HR = 1.17, CI = 0.83-1.67), and all smoking-related diseases (HR = 1.19, CI = 0.97-1.46). However, they had higher mortality for all other causes (1.39, CI = 1.10-1.74), which was largely seen in age 40-59 years (HR = 1.68, CI = 1.11-2.54). Current smokers, with or without ST use, also had significantly elevated HRs for other causes (1.70 and 1.57, respectively), in addition to significant increases in mortality from heart diseases (1.98 and 2.00), malignant neoplasms (2.60 and 2.84), and all smoking-related diseases (2.32 and 2.47).

CONCLUSIONS

This is the first simultaneous mortality follow-up study of older American male smokers and ST users. ST users did not have excess mortality from any smoking-related diseases, but younger users had an elevation in deaths from other causes.

Mutational Signatures in Mandibular Ameloblastoma Correlate with Smoking

Ameloblastoma is a rare tumor of odontogenic epithelium, the low incidence rate of which precludes statistical determination of its molecular characterizations. Despite recent genomic and transcriptomic profiling, the etiology of ameloblastomas remains poorly understood. Risk factors of ameloblastoma development are also largely unknown. Whole exome sequencing was performed on 11 mandibular ameloblastoma samples. We identified 2 convergent mutational signatures in ameloblastoma: 1) a signature found in multiple types of lung cancers with probable etiology of tobacco carcinogens (COSMIC signature 4) and 2) a signature present in gingivobuccal oral squamous cell carcinoma and correlated with tobacco-chewing habits (COSMIC signature 29). These mutational signatures highlight tobacco usage or related mutagens as one possible risk factor of ameloblastoma, since the association of BRAF mutations and smoking was demonstrated in multiple studies. In addition to BRAF hotspot mutations (V600E), we observed clear inter- and intratumor heterogeneities. Interestingly, prior to BRAF mutation, important genes regulating odontogenesis mutated (e.g., corepressor BCOR), possibly playing important roles in tumorigenesis. Furthermore, recurrent mutations in the CDC73 gene, the germline mutations of which predispose patients to the development of jaw tumors, were found in 2 patients, which may lead to recurrence if not targeted by therapeutic drugs. Our unbiased profiling of coding regions of ameloblastoma genomes provides insights to the possible etiology of mandibular ameloblastoma and highlights potential disease risk factors for screening and prevention, especially for Asian patients. Because of the limited sample size and incomplete habitual, dietary, and occupational data, a causal link between tobacco usage and ameloblastoma still requires further investigations.

Relationship between type of smokeless tobacco & risk of cancer: A systematic review

Background & objectives:

Causative linkages of smokeless tobacco (SLT) use with oral potentially malignant disorders and cancers of oral cavity, oesophagus and pancreas have been reported. Published meta-analyses have provided pooled risk estimates for major cancers caused by SLT, both on global and regional levels. This systematic review was aimed at summarizing the available studies on occurrence and mortality risk of common cancers due to various SLT products.

Methods:

PubMed and Google Scholar databases were systematically searched from 1985 till January 2018 for observational studies on SLT and cancer. The included studies were evaluated and data were extracted and reviewed.

Results:

The review included 80 studies providing 121 risk estimates for various cancers. Majority of the studies from South-East Asian Region (SEAR) and Eastern Mediterranean Region (EMR) showed a significant positive association of SLT use with oral [odds ratio (OR) ranging from 1.48 to 27.4] and oesophageal cancers (OR between 2.06 and 12.8), while studies from European Region (EUR) reported a positive association with pancreatic cancer (OR between 1.6 and 2.1). Cancer-related mortality was evaluated in a few reports with higher risk of mortality for lung (OR between 2.0 and 9.1), cervical (OR 2.0) and prostate (OR 2.1) cancers. A wide variation was noted in the association of various cancers and specific SLT products based on their nature, methods of use and inherent toxicity. The majority of chewing tobacco products displayed higher risk for oral and oesophageal cancers while the same was not observed for snus.

Interpretation & conclusions:

This review emphasizes on the significantly positive association of SLT use with oral and oesophageal cancers in SEAR and EMR and pancreatic cancer in EUR. Mortality estimates for SLT-associated cancers need further analysis. Risk analysis for cancers of other sites in SLT users also requires multicentric well-designed studies.

Vulvar cancer: Two pathways with different localization and prognosis

BACKGROUND

Two etiologic pathways for vulvar squamous cell carcinoma (SCC) are described: in a background of lichen sclerosus and/or differentiated vulvar intraepithelial neoplasia and related to high-risk human papillomavirus (HPV) infection with high grade squamous intraepithelial lesion (HSIL) as precursor. The aim was to compare the predilection site and survival of HPV-related to non HPV-related vulvar SCCs.

METHODS

Data of patients treated for primary vulvar SCC at the Radboudumc between March 1988 and January 2015 were analyzed. All histological specimens were tested for HPV with the SPF₁₀/DEIA/LiPA₂₅ system assay and p16^INK4a staining was performed using CINtec® histology kit. Vulvar SCCs were considered HPV-related in case of either >25% p16^INK4a expression and HPV positivity or >25% p16^INK4a expression and HSIL next to the tumor without HPV positivity. Tumor localization, disease specific survival (DSS), disease free survival (DFS) and overall survival (OS) of patients with HPV-related and non HPV-related vulvar SCC were compared.

RESULTS

In total 318 patients were included: 55 (17%) had HPV-related (Group 1) and 263 (83%) had non HPV-related vulvar SCC (Group 2). Tumors in Group 1 were significantly more often located at the perineum compared to Group 2, 30% and 14%, respectively (p=0.001). The DSS, DFS and OS were significantly better in HPV-related than in non HPV-related vulvar SCC patients.

CONCLUSION

HPV-related vulvar SCCs are more frequently located at the perineum and have a favorable prognosis compared to non HPV-related vulvar SCCs. Both localization and HPV-relation could explain this favorable prognosis. HPV-related vulvar SCC seems to be a separate entity.

Smokeless tobacco (snus) use and colorectal cancer incidence and survival: Results from nine pooled cohorts

AIMS

Although smoking is considered to be an established risk factor for colorectal cancer, the current evidence on the association between smokeless tobacco and colorectal cancer is scant and inconclusive. We used pooled individual data from the Swedish Collaboration on Health Effects of Snus Use to assess this association.

METHODS

A total of 417,872 male participants from nine cohort studies across Sweden were followed up for incidence of colorectal cancer and death. Outcomes were ascertained through linkage to health registers. We used shared frailty models with random effects at the study level to estimate hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

During 7,135,504 person-years of observation, 4170 men developed colorectal cancer. There was no clear association between snus use and colorectal cancer overall. Exclusive current snus users, however, had an increased risk of rectal cancer (HR 1.40: 95% CI 1.09, 1.79). There were no statistically significant associations between snus use and either all-cause or colorectal cancer-specific mortality after colorectal cancer diagnosis.

CONCLUSIONS

Our findings, from a large sample, do not support any strong relationships between snus use and colorectal cancer risk and survival among men. However, the observed increased risk of rectal cancer is noteworthy, and in merit of further attention.

International trends in anal cancer incidence rates

Background

Previous studies have reported rapid increases in anal cancer incidence rates in seven high-income countries in North America, Europe and Oceania. There is very limited information on whether this pattern is replicated in other parts of the world. In this study, we examine recent trends in anal cancer incidence in 18 countries worldwide.

Methods

We calculated age-standardized incidence rates for anal squamous cell carcinoma (ASCC) and anal adenocarcinoma (AAC) for a minimum of 13 years through to 2007, using data from the International Agency for Research on Cancer's Cancer Incidence in Five Continents series, and applied joinpoint regression models to assess changes in incidence rates. We also conducted an extended analysis of the data from the USA through to 2012.

Results

ASCC was the main histological subtype in most of the countries considered in this analysis. The incidence of ASCC increased in both men and women in several high-income countries, including Australia, Canada, Denmark, France, Italy, Netherlands, the UK and the USA, whereas it increased only in women in Colombia, Estonia, the Russian Federation, Slovakia and Switzerland. Conversely, there was little change in the incidence of ASCC in either men or women in India, Israel, Japan, Singapore and Spain. The incidence rates of AAC decreased or were stable in most populations.

Conclusions

The ASCC incidence rates increased in both men and women or in women in all countries included in this study, except Asian countries and Spain, where the rates remained unchanged. Population-based preventive measures, including human papillomavirus vaccination and advocacy for safe sexual behaviours, may contribute to curbing the surging burden of the disease.

Smokeless tobacco (snus) is associated with an increased risk of type 2 diabetes: results from five pooled cohorts

BACKGROUND

Smoking and nicotine exposure increase insulin resistance and the risk of type 2 diabetes. Swedish smokeless tobacco (snus) is high in nicotine, and its use is prevalent in Scandinavian countries, but few studies have investigated snus use in relation to diabetes risk.

OBJECTIVE

To explore the association between snus use and risk of type 2 diabetes using pooled data from five cohorts.

METHODS

Analyses were based on prospective studies conducted between 1990 and 2013 including 54 531 never-smoking men and 2441 incident cases of type 2 diabetes identified through screening, self-reporting and hospital and prescription registries. Hazard ratios (HRs) and 95% confidence intervals (CIs) were assessed and adjusted for age, body mass index, educational level, alcohol consumption and physical activity.

RESULTS

Compared to never users, the HR of type 2 diabetes was 1.15 (95% CI: 1.00-1.32) in current users of snus. In individuals consuming 5-6 boxes per week, the HR was 1.42 (95% CI: 1.07-1.87); in those consuming ≥7 boxes per week, the HR was 1.68 (95% CI: 1.17-2.41). Each additional box of snus consumed per week yielded an HR of 1.08 (95% CI: 1.01-1.16).

CONCLUSION

Our findings indicate that high consumption of snus is a risk factor for type 2 diabetes. The risk was similar to that in smokers, implying that smokers will not reduce their risk of type 2 diabetes by changing to snus use. The results also support the notion that nicotine increases the risk of type 2 diabetes.

Tobacco Use and Cancer Risk in the Agricultural Health Study

Background: Cigarettes are well known to cause cancer, but less is known about the risks of other tobacco products and use of more than one product.Methods: We examined cancer incidence in relation to exclusive use of six tobacco products [cigarettes, other combustibles (pipe, cigar, cigarillo), and smokeless tobacco (chewing tobacco, snuff)] in the Agricultural Health Study. We also examined the added cancer risks associated with use of cigarettes and other tobacco products.Results: In our study population of 84,015, ever use of smokeless tobacco was higher than the general United States population, whereas cigarette use was lower and other combustible product use was about the same. The strongest associations for exclusive ever use were for lung cancer [cigarettes HR = 15.48; 95% confidence interval (CI), 11.95-20.06; other combustible tobacco HR = 3.44; 95% CI, 1.53-7.71; smokeless tobacco HR = 2.21; 95% CI, 1.11-4.42]. Compared with exclusive cigarette smokers, cigarette smokers who additionally ever-used another combustible product had higher risks of smoking-related cancers (HR = 1.16; 95% CI, 1.04-1.30), especially among those who smoked cigarettes for more than 15 years.Conclusions and Impact: Cigarette smokers who additionally ever used smokeless tobacco had cancer risks similar to exclusive cigarette smokers. Users of cigarettes and other combustible tobacco may have higher risks of certain cancers than exclusive cigarette users. Cancer Epidemiol Biomarkers Prev; 26(5); 769-78. ©2016 AACR.

Anal human papillomavirus infection: prevalence, diagnosis and treatment of related lesions

Human papillomavirus (HPV) infection is mostly asymptomatic, but may also have many diverse clinical signs encompassing benign ano-genital lesions, and carcinomas. Recently, interest has also particularly focused on anal cancer since, over the last decades, its incidence has been greatly increasing in developed countries, both in women and men and is drastically higher in specific risk groups, such as men who have sex with men (MSM) and HIV-1 infected individuals. Approximately 88% of anal cancer cases worldwide are associated with HPV infection. This review summarizes our current understanding of anal HPV infection, discussing its epidemiology and risk factors in various populations, and the state of the art in the detection of anal HPV infection and its related lesions through both cytology and histology. Finally, we discuss the clinical management and therapy for these lesions.

Background and Current Treatment of Squamous Cell Carcinoma of the Anus

In this review, a summary of our current understanding of squamous cell carcinoma of the anus (SCCA) and the advances in our knowledge of SCCA regarding screening, prevention, the role of the immune system, current treatment and the potential for novel targets are discussed. The present standard of care in terms of treatment is 5-fluorouracil (5-FU) and mitomycin C (MMC) concurrently with radiation, which results in a high level of disease control for small early cancers. Preservation of the anal sphincter is achieved in the majority, although anorectal function is often impaired. Although evidence from prospective studies to support a change in the treatment strategy is lacking, patients with HPV-negative SCCA appear to be less responsive to chemoradiation (CRT) and relapse more frequently. In contrast, HPV-positive tumours usually fare better, but oncological outcomes are modified by smoking and immune incompetence. There is current interest in escalating the radiotherapy dose for larger, more advanced tumours, and de-escalating treatment for HPV-positive tumours. The use of novel immunological treatments to target the underlying different molecular pathways of HPV-positive cancers is exciting.

Risk of Gastrointestinal Cancers among Patients with Appendectomy: A Large-Scale Swedish Register-Based Cohort Study during 1970-2009

BACKGROUND

Removal of the appendix might induce physiological changes in the gastrointestinal tract, and subsequently play a role in carcinogenesis. Therefore, we conducted a nationwide register-based cohort study in Sweden to investigate whether appendectomy is associated with altered risks of gastrointestinal cancers.

METHODS

A population-based cohort study was conducted using the Swedish national registries, including 480,382 eligible patients followed during the period of 1970-2009 for the occurrence of site-specific gastrointestinal cancer (esophageal/gastric/colon/rectal cancer). Outcome and censoring information was collected by linkage to health and demography registers. We examined the incidence of appendectomy in Sweden using data from 1987-2009. We also calculated standardized incidence ratios (SIRs) with 95% confidence intervals (CIs) to estimate the relative gastrointestinal cancer risk through comparison to the general population.

RESULTS

We noted an overall decrease in the age-standardized incidence of appendectomy among the entire Swedish population from 189.3 to 105.6 per 100,000 individuals between 1987 and 2009. Grouped by different discharge diagnosis, acute appendicitis, incidental appendectomy, and entirely negative appendectomy continuously decreased over the study period, while the perforation ratio (18%-23%) stayed relatively constant. Compared to the general population, no excess cancer risk was observed for gastrointestinal cancers under study with the exception of a marginally elevated risk for esophageal adenocarcinoma (SIR 1.32, 95% CI 1.09-1.58).

CONCLUSIONS

In Sweden, the incidence of appendectomy and acute appendicitis has decreased during 1987-2009. No excess gastrointestinal cancer risks were observed among these appendectomized patients, with the possible exception of esophageal adenocarcinoma.

Prevalence and risk factors associated with anal intraepithelial neoplasia among HIV-positive men in Brazil

OBJECTIVE

This study aimed to assess the prevalence of, and associated factors with, anal intraepithelial neoplasia (AIN) among HIV-positive men evaluated at public health services in Brazil.

MATERIALS AND METHODS

This is a multicenter cross-sectional study of HIV-positive male patients attending 6 public AIDS referral clinics in urban Brazil. Participants were interviewed for sociodemographic and behavioral characteristics. Anal swab specimens were collected for anal cytology and HPV DNA testing using L1 polymerase chain reaction. Univariate and multivariate analyses were performed to evaluate risk factors associated with the presence of low-grade squamous intraepithelial lesion (LSIL) and/or high-grade squamous intraepithelial lesion (HSIL).

RESULTS

Anal swabs were collected from 343 participants. Prevalence of LSIL/HSIL was 24.8%. The majority (60.1%) reported sexual intercourse with both men and women in their lifetime. At least 36.7% had 1 or more oncogenic HPV types. Four variables were independently associated with the presence of LSIL/HSIL in multivariate analysis: history of sex with both men and women (odds ratio [OR] = 4.8) or men only (OR = 6.2) compared with those having sex with women only; current cigarette smoking (OR = 2.2); current CD4(+) level between 200 and 500 cells/mm(3) (OR = 2.9) or below 200 cells/mm(3) (OR = 3.8) compared with CD4(+) level above 500 cells/mm(3); and presence of oncogenic anal HPV infection (OR = 9.6).

CONCLUSIONS

We found a high prevalence of AIN among HIV-positive men in Brazil. This population may serve as an important bridge population to women with implications for anogenital HPV infection in both men and women. Our findings confirm the need to assess screening programs for AIN among high-risk groups, similar to those used to prevent cervical cancer.

Health risks related to dual use of cigarettes and snus - a systematic review

Reviews show that using snus (Swedish-type moist snuff) is much safer than smoking, with no increased risk from snus of cancer or circulatory disease yet demonstrated, but have not investigated possible health effects from dual use of cigarettes and snus. This review considers studies where health risks can be compared in dual users, those who only use snus or only smoke, and those who use neither product. The interaction RR, the ratio of RRs associated with snus use in smokers and in non-smokers, was used to test for special effects of dual use. Of 51 interaction RRs presented, only one (for gestational hypertension in a study based on the Swedish Medical Register) was significantly (p<0.05) above 1.0, and RRs below 1.0 were commoner, perhaps as cigarette consumption is lower in dual users than those who only smoke. Dual users more often initiate tobacco use with cigarettes than snus. Dual use is much commoner in adolescents than adults, possibly because many tobacco users try both products, eventually settling on one. Epidemiological evidence from various sources, though suffering from weaknesses, consistently suggests concomitant snus use increases smoking quit rates, and aligns with evidence from RCTs using snus to aid smoking cessation.

Epidemiological evidence relating snus to health--an updated review based on recent publications

An earlier review summarized evidence relating use of snus (Swedish-type moist snuff) to health and to initiation and cessation of smoking. This update considers the effect recent publications on snus use and health have on the overall evidence. The additional evidence extends the list of neoplastic conditions unassociated with snus use (oropharynx, oesophagus, stomach, lung) to include colorectal cancer and acoustic neuroma, and further undermines the weakly-based argument that snus use increases the risk of pancreatic cancer, although there is a report of poorer cancer survival in users. It remains undemonstrated that “snuff-dipper’s lesion” increases risk of oral cancer, and recent publications add to the evidence that snus use has no effect on periodontitis or dental caries. Although onset of acute myocardial infarction is not adversely associated with snus use, there is some evidence of an association with reduced survival. Whether this is a direct effect of snus use or a result of confounding by socioeconomic status or other factors requires further investigation, as does a report of an increased risk of heart failure in snus users. Even if some adverse health effects of snus use do exist, it remains clear that they are far less than those of smoking.

Effects of smoking and antioxidant micronutrients on risk of colorectal cancer

BACKGROUND & AIMS

Antioxidant intake has been reported to increase the risk of colorectal cancer (CRC) for smokers, yet reduce the risk for nonsmokers. We investigated the association between tobacco smoking and risk of colon or rectal cancer, and whether dietary and supplemental intake of the antioxidant vitamins A, C, E, β-carotene, selenium, zinc, and manganese affects the risk of CRC among smokers.

METHODS

Data on smoking habits and antioxidant intake were analyzed for 54,208 participants in the Danish Prospective Diet, Cancer and Health Study. Of these participants, 642 were diagnosed with colon cancer and 348 were diagnosed with rectal cancer. Hazard ratios and 95% confidence intervals were estimated using Cox proportional hazard models. Principal components were used to analyze intake of combinations of antioxidants.

RESULTS

Ever smoking increased the risk for CRC (hazard ratio, 1.19; 95% confidence interval, 1.03-1.37), especially for rectal cancer. Smoking for at least 20 years was associated with a 26% increase in risk of CRC, compared with never smokers, and smoking 20 g tobacco or more each day was associated with a 30% increase in risk. Smoking for more than 30 years, or more than 20 g tobacco each day, was associated with a 48% increase in risk of rectal cancer. We did not observe an interaction between smoking and antioxidant consumption on risk of CRC.

CONCLUSIONS

Tobacco smoking increases the risk for CRC. We did not observe that consumption of antioxidant micronutrients modulates the effects of smoking on CRC risk.

Smoking among construction workers: the nonlinear influence of the economy, cigarette prices, and antismoking sentiment

Little research has been conducted on the influence of macroeconomic environments on smoking among blue-collar workers, a group with high smoking prevalence and that is especially vulnerable to the effects of changing economic circumstances. Using data from 52,418 construction workers in the Tobacco Use Supplement to the United States Current Population Survey, we examined the association of labor market shock, cigarette prices, and state antismoking sentiments with smoking status and average number of cigarettes smoked daily. Data analysis included the use of multiple linear and logistic regressions, which employed the sampling and replicate weights to account for sampling design. Unemployed, American-Indian, lower-educated and lower-income workers had higher smoking rates. Labor market shock had a quadratic association, which was non-significant for smoking status and significant for number of cigarettes. The association of cigarette prices with smoking status became non-significant after adjusting for state-level antismoking sentiment. State-level antismoking sentiment had significant quadratic association with smoking status among employed workers and significant quadratic association with number of cigarettes for all smokers. The study highlights how both workplace-based smoking cessation interventions and antismoking sentiments could further contribute to disparities in smoking by employment status.

Diabetes but not insulin is associated with higher colon cancer mortality

AIM: To evaluate whether diabetic patients had a higher risk of colon cancer mortality and its associated risk factors.

METHODS: The sex-specific crude and age-standardized (to the 2000 World Health Organization population) mortality rates of colon cancer in the Taiwanese general population were first calculated from 1995 to 2006. The trends were evaluated by linear regression. A total of 113 347 diabetic men and 131 573 diabetic women aged ≥ 25 years at recruitment from 1995 to 1998 were followed up until the end of 2006. Age/sex-specific colon cancer mortality rate ratios were calculated comparing the mortality rates of the diabetic patients with the average mortality rates of the general population within 12 years (1995-2006). A sub-cohort of diabetic patients (42 260 men and 49 405 women) was interviewed using a baseline questionnaire and Cox’s regression was used to evaluate the risk factors for colon cancer mortality in these diabetic patients.

RESULTS: The crude and age-standardized trends of colon cancer mortality from 1995 to 2006 increased significantly for both sexes in the general population. A total of 641 diabetic men and 573 diabetic women died of colon cancer, with a mortality rate of 74.4 and 54.3 per 100 000 person-years, respectively. Mortality rate ratios [95% confidence intervals (CIs)] showed a significantly higher risk of mortality from colon cancer for the diabetic patients compared to the general population, with the magnitude increasing with decreasing age: 1.65 (1.40-1.95), 2.01 (1.78-2.27), 2.75 (2.36-3.21) and 5.69 (4.65-6.96) for ≥ 75, 65-74, 55-64 and 25-54 years old, respectively, for men; and 1.46 (1.24-1.72), 2.09 (1.84-2.38), 2.67 (2.27-3.14) and 3.05 (2.29-4.06), respectively, for women. Among the sub-cohort of diabetic patients who had been interviewed with the baseline questionnaire, including information on age, sex, diabetes duration, diabetes type, body mass index, smoking, insulin use and area of residence, age and smoking were significantly predictive for colon cancer mortality, with respective adjusted hazard ratios (HRs) (95% CIs) of 1.077 (1.066-1.088) and 1.384 (1.068-1.792). Diabetes duration became a significant factor when those who died of colon cancer within 5 years of diabetes diagnosis were excluded to minimize the possible contamination of diabetes caused by incipient colon cancer, with an adjusted hazard ratio of 1.021 (1.007-1.034). Sex, diabetes type, insulin use, body mass index and area of residence were not significant predictors for colon cancer mortality in the diabetic patients. Although insulin use was categorized into subgroups of duration of use (non-users and users < 5 years, 5-9 years and ≥ 10 years), none of the HRs for colon cancer mortality was significant with regards to different durations of insulin use.

CONCLUSION: Colon cancer mortality is increasing in Taiwan. A higher risk is observed in diabetic patients. Smoking, but not insulin use, is a modifiable risk factor.

Use of snus and acute myocardial infarction: pooled analysis of eight prospective observational studies

The use of snus (also referred to as Scandinavian or Swedish moist smokeless tobacco), which is common in Sweden and increasing elsewhere, is receiving increasing attention since considered a tobacco smoke "potential reduction exposure product". Snus delivers a high dose of nicotine with possible hemodynamic effects, but its impact on cardiovascular morbidity and mortality is uncertain. The aim of this study was to investigate whether snus use is associated with risk of and survival after acute myocardial infarction (AMI). Data from eight prospective cohort studies set in Sweden was pooled and reanalysed. The relative risk of first time AMI and 28-day case-fatality was calculated for 130,361 men who never smoked. During 2,262,333 person-years of follow-up, 3,390 incident events of AMI were identified. Current snus use was not associated with risk of AMI (pooled multivariable hazard ratio 1.04, 95 % confidence interval 0.93 to 1.17). The short-term case fatality rate appeared increased in snus users (odds ratio 1.28, 95 % confidence interval 0.99 to 1.68). This study does not support any association between use of snus and development of AMI. Hence, toxic components other than nicotine appear implicated in the pathophysiology of smoking related ischemic heart disease. Case fatality after AMI is seemingly increased among snus users, but this relationship may be due to confounding by socioeconomic or life style factors.

[Smokeless tobacco]

Use of smokeless tobacco (ST) (chewing tobacco and snuff) can lead to a number of consequences detrimental to health. ST rapidly delivers high doses of nicotine, which can lead to dependence and is also a source of carcinogenic nitrosamines. Changes usually develop in the mouth area where the ST is most often placed. Non-malignant oral lesions include leuko-oedema, hyperkeratotic lesions of the oral mucosa and localised periodontal disease. Oral premalignant lesions are leukoplakia, erythroplakia, submucosal fibrosis and lichen planus. Betel chewing, with or without tobacco, may increase the incidence of oral cancer. There is conflicting evidence with regard to snuff users about the risk of oral and gastro-oesophageal cancer. ST use is a risk factor for pancreatic cancer and may increase the risk of fatal myocardial infarction and ischemic stroke. During pregnancy, ST is associated with an increase in pre-eclampsia, preterm delivery and stillbirth. Nicotine replacement therapy and bupropion reduce withdrawal symptoms and tobacco craving during ST cessation. However, they have not been shown to help long-term abstinence. Information concerning the potential hazards of ST products should be incorporated into educational programmes to discourage its use and to help users to quit. Smokeless tobacco is not recommended to help smoking cessation.

Six-month incidence, persistence, and factors associated with persistence of anal human papillomavirus in men: the HPV in men study

BACKGROUND

Although there are limited numbers of incidence and persistence estimates for anal human papillomavirus (HPV) in women and in men who have sex with men (MSM), there are no such reports for men who have sex with women (MSW).

METHODS

Genotyping was performed on anal samples from men, aged 18-70, from São Paulo, Brazil; Cuernavaca, Mexico; and Tampa, Florida, who provided specimens at enrollment and the 6-month visit of a 4-year prospective study. Eligibility included no history of genital warts or human immunodeficiency virus. A total of 954 MSW and 156 MSM provided evaluable specimens at both visits. Persistence was defined as type-specific infection at each visit.

RESULTS

Incident anal infection was common among both MSM and MSW but generally higher for MSM for HPV groups and specific genotypes. A total of 5.1% of MSM and 0.0% of MSW had a persistent HPV-16 infection at the 6-month visit. Cigarette smoking among MSM and age among MSW were associated with persistent infection with any HPV genotype.

CONCLUSIONS

Although anal HPV infection is commonly acquired by both MSW and MSM, incident events and persistence occurred more often among MSM. Cigarette smoking is a modifiable risk factor that may contribute to HPV persistence among MSM.

The scientific foundation for tobacco harm reduction, 2006-2011

Over the past five years there has been exponential expansion of interest in tobacco harm reduction (THR), with a concomitant increase in the number of published studies. The purpose of this manuscript is to review and analyze influential contributions to the scientific and medical literature relating to THR, and to discuss issues that continue to stimulate debate. Numerous epidemiologic studies and subsequent meta-analyses confirm that smokeless tobacco (ST) use is associated with minimal risks for cancer and for myocardial infarction; a small increased risk for stroke cannot be excluded. Studies from Sweden document that ST use is not associated with benign gastrointestinal disorders and chronic inflammatory diseases. Although any form of nicotine should be avoided during pregnancy, the highest risks for the developing baby are associated with smoking. It is documented that ST use has been a key factor in the declining rates of smoking and of smoking-related diseases in Sweden and Norway. For other countries, the potential population health benefits of ST are far greater than the potential risks. In follow-up studies, dual users of cigarettes and ST are less likely than exclusive smokers to achieve complete tobacco abstinence, but they are also less likely to be smoking. The health risks from dual use are probably lower than those from exclusive smoking. E-cigarette users are not exposed to the many toxicants, carcinogens and abundant free radicals formed when tobacco is burned. Although laboratory studies have detected trace concentrations of some contaminants, it is a small problem amenable to improvements in quality control and manufacturing that are likely with FDA regulation as tobacco products. There is limited evidence from clinical trials that e-cigarettes deliver only small doses of nicotine compared with conventional cigarettes. However, e-cigarette use emulates successfully the cigarette handling rituals and cues of cigarette smoking, which produces suppression of craving and withdrawal that is not entirely attributable to nicotine delivery. THR has been described as having "the potential to lead to one of the greatest public health breakthroughs in human history by fundamentally changing the forecast of a billion cigarette-caused deaths this century."

Swedish snus and the GothiaTek® standard

Some smokeless tobacco products, such as Swedish snus, are today considered to be associated with substantially fewer health hazards than cigarettes. This risk differential has contributed to the scientific debate about the possibilities of harm reduction within the tobacco area. Although current manufacturing methods for snus build on those that were introduced more than a century ago, the low levels of unwanted substances in modern Swedish snus are largely due to improvements in production techniques and selection of raw materials in combination with several programs for quality assurance and quality control. These measures have been successively introduced during the past 30-40 years. In the late 1990s they formed the basis for a voluntary quality standard for Swedish snus named GothiaTek^®. In recent years the standard has been accepted by the members of the trade organization European Smokeless Tobacco Council (ESTOC) so it has now evolved into an industrial standard for all smokeless tobacco products in Europe.

The initial impetus for the mentioned changes of the production was quality problems related to microbial activity and formation of ammonia and nitrite in the finished products. Other contributing factors were that snus came under the jurisdiction of the Swedish Food Act in 1971, and concerns that emerged in the 1960s and 1970s about health effects of tobacco, and the significance of agrochemical residues and other potential toxicants in food stuffs.

This paper summarizes the historical development of the manufacture of Swedish snus, describes the chemical composition of modern snus, and gives the background and rationale for the GothiaTek^® standard, including the selection of constituents for which the standard sets limits. The paper also discusses the potential future of this voluntary standard in relation to current discussions about tobacco harm reduction and regulatory science in tobacco control.