Cigar and pipe smoking, smokeless tobacco use and pancreatic cancer: an analysis from the International Pancreatic Cancer Case-Control Consortium (PanC4)

Earlier Diagnosis of Pancreatic Cancer: Is It Possible?

Pancreatic ductal adenocarcinoma has a very high mortality rate which has been only minimally improved in the last 30 years. This high mortality is closely related to late diagnosis, which is usually made when the tumor is large and has extensively infiltrated neighboring tissues or distant metastases are already present. This is a paradoxical situation for a tumor that requires nearly 15 years to develop since the first founding mutation. Response to chemotherapy under such late circumstances is poor, resistance is frequent, and prolongation of survival is almost negligible. Early surgery has been, and still is, the only approach with a slightly better outcome. Unfortunately, the relapse percentage after surgery is still very high. In fact, early surgery clearly requires early diagnosis. Despite all the advances in diagnostic methods, the available tools for improving these results are scarce. Serum tumor markers permit a late diagnosis, but their contribution to an improved therapeutic result is very limited. On the other hand, effective screening methods for high-risk populations have not been fully developed as yet. This paper discusses the difficulties of early diagnosis, evaluates whether the available diagnostic tools are adequate, and proposes some simple and not-so-simple measures to improve it.

Review with meta-analysis relating North American, European and Japanese snus or smokeless tobacco use to major smoking-related diseases

BACKGROUND

While extensive information exists relating cigarette smoking to the risk of lung cancer, chronic obstructive pulmonary disease (COPD), ischaemic heart disease (IHD) or acute myocardial infarction (AMI), and stroke, far less information is available on risks from moist snuff (“snus”) or smokeless tobacco (ST) in United States/Canada, Europe or Japan.

AIM

To summarize data from the selected countries on risks of the four diseases associated with current ST or snus use.

METHODS

Publications in English in 1990-2020 were considered that, based on epidemiological studies in North America, Europe or Japan, estimated risks of lung cancer, COPD, IHD/AMI, or stroke according to use of ST or snus. The studies should involve at least 100 cases of the disease considered, and not be restricted to those with specific other diseases. Medline literature searches were conducted, selecting papers initially from examination of titles and abstracts, and then from full texts. Further papers were sought from reference lists in selected papers, reviews and meta-analyses. For each disease, relative risk estimates adjusted at least for age were extracted relating ST or snus use to risk, and combined using random-effects meta-analysis. The estimates were mainly for current vs. never or non-current use, but results for ever vs never use were also considered.

RESULTS

Seven publications reported results for ST use from six United States studies. The most useful results came from four studies which provided results for current vs. never use. Random-effects meta-analyses of these results showed an increased risk for each disease, clearest for lung cancer (relative risk 1.59, 95% confidence interval 1.06-2.39, based on 4 estimates) and COPD (1.57, 1.09-2.26, n = 3), but also significant (at P < 0.05) for IHD (1.26, 1.10-1.45, n = 4) and stroke (1.27, 1.03-1.57, n = 4). Also including results for ever vs. never use from two other studies increased the lung cancer estimate to 1.80 (1.23-2.64, n = 6), but had little effect on the other estimates. For snus, 16 publications described results from 12 studies, one in Norway and the rest in Sweden. There were no results for COPD, and only three for lung cancer, with these reporting a relative risk of 0.80 (0.40-1.30) for current vs never use. More extensive data were available for IHD/AMI and stroke. Using the latest results from each study, combined estimates for current vs. never use were 1.00 (0.91-1.11, n = 5) for IHD/AMI and 1.05 (0.95-1.17, n = 2) for stroke, while for current vs. non-current use they were 1.10 (0.92-1.33, n = 9) for IHD/AMI and 1.12 (0.86-1.45, n = 9) for stroke. Meta-analyses including earlier results from some studies also showed no significant association between snus use and IHD/AMI or stroke. No relevant results were found for Japan.

CONCLUSION

Risks of smoking-related diseases from snus use in Scandinavia are not demonstrated, while those from ST use in the United States are less than from smoking.

Smoking and Pancreatic Cancer: Smoking Patterns, Tobacco Type, and Dose-Response Relationship

Pancreatic cancer (PC) is the primary cause of cancer death in the United States and Europe. Despite remarkable advances in the molecular understanding of PC and advances in new therapeutic approaches, PC remains a disease with a poor prognosis. Although evidence indicates that long-term smoking is a major cause of PC, the molecular pathways behind smoking-induced PC pathogenesis are not fully understood. Smoking cessation can significantly reduce the occurrence of PC.

This review explores the processes underpinning the influence of smoking-related chemicals on fibrosis and inflammation and provides insight into the etiology of PC. In the future, a thorough exploration of the effects of smoking chemicals on the activity of pancreatic stem cells and then on the essential mediators of the association with cancer cells would likely yield new diagnostic targets.

Pancreatic cancer epidemiology: understanding the role of lifestyle and inherited risk factors

Pancreatic cancer is a leading cause of cancer death worldwide and its global burden has more than doubled over the past 25 years. The highest incidence regions for pancreatic cancer include North America, Europe and Australia, and although much of this increase is due to ageing worldwide populations, there are key modifiable risk factors for pancreatic cancer such as cigarette smoking, obesity, diabetes and alcohol intake. The prevalence of these risk factors is increasing in many global regions, resulting in increasing age-adjusted incidence rates for pancreatic cancer, but the relative contribution from these risk factors varies globally due to variation in the underlying prevalence and prevention strategies. Inherited genetic factors, although not directly modifiable, are an important component of pancreatic cancer risk, and include pathogenic variants in hereditary cancer genes, genes associated with hereditary pancreatitis, as well as common variants identified in genome-wide association studies. Identification of the genetic changes that underlie pancreatic cancer not only provides insight into the aetiology of this cancer but also provides an opportunity to guide early detection strategies. The goal of this Review is to provide an up-to-date overview of the established modifiable and inherited risk factors for pancreatic cancer.

Updated risk factors to inform early pancreatic cancer screening and identify high risk patients

Pancreatic adenocarcinoma (PDAC) is associated with poor clinical outcomes and incomplete responses to conventional therapy. Therefore, there is an unmet clinical need to better understand the predisposing factors for pancreatic cancer in hopes of providing early screening to high-risk patients. While select risk factors such as age, race, and family history, or predisposing syndromes are unavoidable, there are several new and established risk factors that allow for intervention, namely by counseling patients to make the appropriate lifestyle modifications. Here, we discuss the best-studied risk factors for PDAC such as tobacco use and chronic pancreatitis, as well as newly emerging risk factors including select nutritional deficits, bacterial infections, and psychosocial factors. As several of these risk factors appear to be additive or synergistic, by understanding their relationships and offering coordinated, multidisciplinary care to high-risk patients, it may be possible to reduce pancreatic cancer incidence and improve clinical outcomes through early detection.

Pancreatic Cancer Risk in Relation to Lifetime Smoking Patterns, Tobacco Type, and Dose-Response Relationships

BACKGROUND

Despite smoking being a well-established risk factor for pancreatic cancer, there is a need to further characterize pancreatic cancer risk according to lifespan smoking patterns and other smoking features, such as tobacco type. Our aim was to deeply investigate them within a large European case-control study.

METHODS

Tobacco smoking habits and other relevant information were obtained from 2,009 cases and 1,532 controls recruited in the PanGenEU study using standardized tools. Multivariate logistic regression analysis was performed to evaluate pancreatic cancer risk by smoking characteristics and interactions with other pancreatic cancer risk factors. Fractional polynomials and restricted cubic splines were used to test for nonlinearity of the dose-response relationships and to analyze their shape.

RESULTS

Relative to never-smokers, current smokers [OR = 1.72; 95% confidence interval (95% CI), 1.39-2.12], those inhaling into the throat (OR = 1.48; 95% CI, 1.11-1.99) or chest (OR = 1.33; 95% CI, 1.12-1.58), and those using nonfiltered cigarettes (OR = 1.69; 95% CI, 1.10-2.61), were all at an increased pancreatic cancer risk. Pancreatic cancer risk was highest in current black tobacco smokers (OR = 2.09; 95% CI, 1.31-3.41), followed by blond tobacco smokers (OR = 1.43; 95% CI, 1.01-2.04). Childhood exposure to tobacco smoke relative to parental smoking was also associated with increased pancreatic cancer risk (OR = 1.24; 95% CI, 1.03-1.49). Dose-response relationships for smoking duration, intensity, cumulative dose, and smoking cessation were nonlinear and showed different shapes by tobacco type. Effect modification by family history of pancreatic cancer and diabetes was likely.

CONCLUSIONS

This study reveals differences in pancreatic cancer risk by tobacco type and other habit characteristics, as well as nonlinear risk associations.

IMPACT

This characterization of smoking-related pancreatic cancer risk profiles may help in defining pancreatic cancer high-risk populations.

Activation of PI3K/Akt/NF-kB Signaling Mediates Swedish Snus Induced Proliferation and Apoptosis Evasion in the Rat Forestomach: Modulation by Blueberry

BACKGROUND AND OBJECTIVES

The present study was undertaken to ascertain whether the modulatory effects of blueberries on cell proliferation induced by Swedish snus in the rat forestomach epithelium is mediated via abrogation of the PI3K/Akt/NFκB signaling axis that regulates cell fate decision.

METHODS

The transcript and protein expression of genes involved in cell cycle progression and apoptosis, as well as canonical PI3K/Akt/NF-κB signaling pathways, were analyzed by qRT-PCR, immunoblotting and ELISA. Expression profiling of noncoding RNAs (ncRNAs) that influence PI3K/Akt/NF-κB signaling was undertaken. TUNEL assay was performed using flow cytometry.

RESULTS

Administration of snus induced basal cell hyperplasia in the rat forestomach with increased cell proliferation and inhibition of apoptosis. This was associated with the activation of PI3K/Akt/NFκB signaling. Coadministration of blueberries significantly suppressed snus-induced hyperplasia. Analysis of the molecular mechanisms revealed that blueberries suppress the phosphorylation of Akt, NF-κB and IKKβ, prevent nuclear translocation of NF-κB and modulate the expression of microRNAs that influence PI3K/Akt/NF-κB signaling.

CONCLUSION

Taken together, the results of the current study provide compelling evidence that blueberries exert significant protective effects against snus-induced soft tissue changes in the rat forestomach epithelium mediated by inhibiting key molecular players in the PI3K/Akt/NF-κB signaling axis. Long-term studies on the impact of snus exposure on various cellular processes, signaling pathways, and the interplay between genetic and epigenetic mechanisms are however warranted. The results of this investigation may contribute to the development of protection against soft tissue changes induced by smokeless tobacco in the human oral cavity.

Environmental Risk Factors of Pancreatic Cancer

Despite the advancement in medical knowledge that has improved the survival rate of many cancers, the survival rate of pancreatic cancer has remained dismal with a five-year survival rate of only 9%. The poor survival of pancreatic cancer emphasizes the urgent need to identify the causes or the risk factors of pancreatic cancer in order to establish effective preventive strategies. This review summarizes the current evidence regarding the environmental (non-genetic, including lifestyle, and clinical factors) risk factors of pancreatic cancer. Based on the current evidence, the established risk factors of pancreatic cancer are cigarette smoking, chronic diabetes, and obesity. Other strong risk factors include low consumption of fruits and vegetables, excess consumption of alcohol, poor oral hygiene, and the lack of allergy history. In the future, more studies are needed to identify additional risk factors of pancreatic cancer, especially the modifiable risk factors that could be included in a public health campaign to educate the public in order to reduce the incidence of pancreatic cancer.

Factors effecting the induction of rat forestomach hyperplasia induced by Swedish oral smokeless tobacco (snus)

Long term exposure to oral smokeless tobacco may induce lesions in the oral cavity characterized by a hyperplastic epithelium. The possible role of nicotine and the physical properties of oral tobacco for developing these lesions, as well as of dysplasia and neoplasia is unclear. Low nitrosamine Swedish snus as well as non-genotoxic butylated hydroxyanisole induces increased cellular proliferation in the rat forestomach epithelia. Using this model, we report here on the effects of nicotine, pH, and particle size. Snus with different properties had no impact on oxidative stress as determined by 8-oxo-7,8-dihydro-2'-deoxyguanosine, or on interleukin IL-1b. Whereas BHA boosted IL-6, probably due to the presence of nicotine. there was no significant enhancement of cell divisions with increasing particle size, although in individual samples the variations in proliferation rates increased greatly with increasing particle size. Conforming to human experience, the enhanced cell proliferation caused by snus was found to be completely reversible. A cacao bean extract had a protective action similar to that previously found for blueberries. The main cause of the observed tobacco induced cell proliferation could be mechanical irritation, possibly in combination with nicotine, whereas within the studied range, pH did not affect the rate of cell division.

[Old and new tobacco products]

Tobacco use is not just about manufactured cigarettes. Rolling tobacco, highly prized in the wake of price increases, is estimated to carry more toxic agents than its counterpart. This study shows that the use of cigar, pipe, cigarillos and narghile also leads to a cohort of pathologies similar to or more than what is known for smoking single cigarettes. Exotic, liquid or heated forms do just as much. The non-smoked tobacco, often fallen into disuse in France is very used in the United States and especially in Scandinavia. Denuded of inhaled products, it is often pointed as a form of reduction of smoking risks. Its use by athletes in all countries as a doping attitude, especially in ski disciplines, required a campaign of prevention within the federations concerned.

Use of rodent data for cancer risk assessment of smokeless tobacco in the regulatory context

To support risk management decisions, information from different fields has been integrated in this presentation to provide a realistic quantitative cancer risk assessment of smokeless tobacco. Smoking among Swedish men is currently below 10%, while about 20% use a special smokeless tobacco (snus) as a substitute for cigarettes. Epidemiological data and molecular biomarkers demonstrate that rodent bioassays with tobacco specific nitrosamines (TSNA) overestimate cancer risk from snus by more than one order of magnitude. The underlying reasons are discussed. DNA damage constitutes a necessary, although not sufficient prerequisite for cancer initiation. Individuals who have not used tobacco exhibit DNA lesions identical with those induced by TSNA. No increase above this adduct background can be shown from snus, and extensive epidemiological studies in Sweden have failed to demonstrate elevated cancer risks even in long term users. A "bench mark" for acceptable risk of 1/10(6) derived from rodent data has been suggested when regulating snus. By relating similarly derived estimates for some food contaminants, the implementation even of a limit of 1/10(4) may be unrealistic. The management of smokeless tobacco products has rarely been based on a scientifically sound risk assessment, where attention is given to the outstandingly higher hazards associated with smoking.

Use of moist oral snuff (snus) and pancreatic cancer: Pooled analysis of nine prospective observational studies

While smoking is a well-established risk factor for pancreatic cancer, the effect of smokeless tobacco is less well understood. We used pooled individual data from the Swedish Collaboration on Health Effects of Snus Use to assess the association between Swedish snus use and the risk of pancreatic cancer. A total of 424,152 male participants from nine cohort studies were followed up for risk of pancreatic cancer 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) adjusted for confounding factors. During 9,276,054 person-years of observation, 1,447 men developed pancreatic cancer. Compared to never-snus use, current snus use was not associated with risk of pancreatic cancer (HR 0.96, 95% CI 0.83-1.11) after adjustment for smoking. Swedish snus use does not appear to be implicated in the development of pancreatic cancer in men. Tobacco smoke constituents other than nicotine or its metabolites may account for the relationship between smoking and pancreatic cancer.

Dietary acrylamide and the risk of pancreatic cancer in the International Pancreatic Cancer Case-Control Consortium (PanC4)

Background

Occupational exposure to acrylamide was associated with excess mortality from pancreatic cancer, though in the absence of dose-risk relationship. Few epidemiological studies have examined the association between acrylamide from diet and pancreatic cancer risk.

Patients and methods

We considered this issue in a combined set of 1975 cases of pancreatic cancer and 4239 controls enrolled in six studies of the Pancreatic Cancer Case-Control Consortium (PanC4). We calculated pooled odds ratios (ORs) and their 95% confidence intervals (CI) by estimating study-specific ORs through multivariate unconditional logistic regression models and pooling the obtained estimates using random-effects models.

Results

Compared with the lowest level of estimated dietary acrylamide intake, the pooled ORs were 0.97 (95% CI, 0.79-1.19) for the second, 0.91 (95% CI, 0.71-1.16) for the third, and 0.92 (95% CI, 0.66-1.28) for the fourth (highest) quartile of intake. For an increase of 10 µg/day of acrylamide intake, the pooled OR was 0.96 (95% CI, 0.87-1.06), with heterogeneity between estimates (I2 = 67%). Results were similar across various subgroups, and were confirmed when using a one-stage modelling approach.

Conclusions

This PanC4 pooled-analysis found no association between dietary acrylamide and pancreatic cancer.

Patterns of Smoking and Snus Use in Sweden: Implications for Public Health

There has been concern that the availability of alternative less harmful forms of nicotine might inhibit smoking cessation and/or encourage those who would not otherwise have smoked to do so. The plausibility of such effects can be best assessed by looking at population trends in use of smoking in relation to alternatives. This paper looks at the relationships between snus use and smoking in Sweden. Analyses are based on a data set for the period January 2003 to February 2011 from a long-term study covering nationally representative samples of the Swedish population aged 18–79, with a total study population of 60,675 individuals. Questionnaires made it possible to identify detailed tobacco use categories and use trajectories. The results showed that uptake of snus use is much more common in males than females. Those who began daily tobacco use using snus were much less likely to subsequently take up smoking than those who had not, both among males (17.6% vs. 45.9%), and females (8.2% vs. 40.2%). Further, among those who started using snus after starting as smokers, 76.3% of men and 71.6% of women had stopped smoking completely, including 31.5% of the men and 28.6% of the women who had quit all forms of tobacco. Indeed, those who were primary snus users were also more likely to have quit altogether than those who only ever smoked. Snus was also reported as the most common smoking cessation aid among men and yielded higher success rates than nicotine replacement therapy and other alternatives. As conclusions, snus has both contributed to decreasing initiation of smoking and, when used subsequent to smoking, appears to facilitate smoking cessation. All these effects suggest that the availability and use of snus has been a major factor behind Sweden’s record-low prevalence of smoking and the lowest level of tobacco-related mortality among men in Europe.

Pancreatic Cancer: A Review

Pancreatic cancer is now the third leading cause of cancer related deaths in the United States, yet advances in treatment options have been minimal over the past decade. In this review, we summarize the evaluation and treatments for this disease. We highlight molecular advances that hopefully will soon translate into improved outcomes.

Environmental risk factors for pancreatic cancer: an update

Pancreatic cancer (PC) is one of the most aggressive diseases. Only 10 % of all PC cases are thought to be due to genetic factors. Here, we analyzed the most recently published case-control association studies, meta-analyses, and cohort studies with the aim to summarize the main environmental factors that could have a role in PC. Among the most dangerous agents involved in the initiation phase, there are the inhalation of cigarette smoke, and the exposure to mutagenic nitrosamines, organ-chlorinated compounds, heavy metals, and ionizing radiations. Moreover, pancreatitis, high doses of alcohol drinking, the body microbial infections, obesity, diabetes, gallstones and/or cholecystectomy, and the accumulation of asbestos fibers seem to play a crucial role in the progression of the disease. However, some of these agents act both as initiators and promoters in pancreatic acinar cells. Protective agents include dietary flavonoids, marine omega-3, vitamin D, fruit, vegetables, and the habit of regular physical activity. The identification of the factors involved in PC initiation and progression could be of help in establishing novel therapeutic approaches by targeting the molecular signaling pathways responsive to these stimuli. Moreover, the identification of these factors could facilitate the development of strategies for an early diagnosis or measures of risk reduction for high-risk people.

Trends and Factors Related to Smokeless Tobacco Use in the United States

BACKGROUND

While declines in smoking prevalence in the United States have been well documented, trends in smokeless tobacco (SLT) use are less clear. This study updates previous analyses of US SLT use prevalence to better understand trends and factors related to SLT use.

METHODS

We used the Tobacco Use Supplement of the Current Population Survey (TUS-CPS) to examine trends and factors related to SLT use using joinpoint and logistic regression models. SLT consumption from 1985 to 2011 was obtained from the 2011 Federal Trade Commission Smokeless Tobacco Report. Sensitivity analyses were conducted for assessing the impact of varying frequency definitions of SLT use.

RESULTS

Decreasing trends in smoking and SLT prevalence overall were observed from 1992 to 2003 independently of use definition. SLT prevalence in the total adult population significantly decreased at an annual percent change (APC) of 4.5% per year from 1992 to 2003, but has been approximately constant ever since. Similar patterns were also found in adult males (APC = -4.4%) and young males (APC = -9.5%). SLT per capita consumption decreased significantly from 1991 to 1999 (APC = -2.2%), but has since decreased at only 0.35% per year (1999-2011). SLT use was found to be associated with former smoker status, younger age, white race, living in rural areas, residence in the South, lower education and unemployment, adjusting for other factors.

CONCLUSIONS

Declines in SLT use were found in the United States, suggesting tobacco control has had positive impacts, but these have slowed since 2003. Targeting tobacco control policies to at-risk demographic groups is needed to further reduce SLT use in the United States.

IMPLICATIONS

This study confirms that the declines in SLT use prevalence stopped in 2003 across different demographic groups, consistent with trends in SLT consumption. In addition, the longer period of analysis in comparison with earlier studies allows for quantitative characterization of SLT use trends using joinpoint regression. The study also shows the impact of different SLT use definitions in determining tobacco product use prevalence and trends.

Epidemiology and Inherited Predisposition for Sporadic Pancreatic Adenocarcinoma

Given the changing demographics of Western populations, the numbers of pancreatic cancer cases are projected to increase during the next decade. Diabetes, recent cigarette smoking, and excess body weight are the cancer's most consistent risk factors. The search for common and rare germline variants that influence risk of pancreatic cancer through genome-wide association studies and high-throughput-sequencing-based studies is underway and holds the promise of increasing the knowledge of variants and genes that play a role in inherited susceptibility of this disease. Research reported in this review has advanced the understanding of pancreatic cancer.

Inhibition by blueberries (bilberries) and extract from milk thistle of rat forestomach hyperplasia induced by oral smokeless tobacco (Swedish snus)

The aim of this study was to identify palatable additives which have a significant protective action against soft tissue changes in the oral cavity caused by Swedish smokeless tobacco ("snus"), and that satisfy existing legal requirements. Although the cancer risk from snus is extremely low, long term use may result in highly undesirable keratotic lesions and associated epithelial abnormalities in the oral cavity. The rat forestomach, which is vulnerable to the irritative action of non-genotoxic compounds like butylated hydroxyanisole, propionic acid as well as snus, was chosen as an experimental model. Studied toxicological endpoints included histopathology and cellular proliferation based on DNA incorporation of bromodeoxyuridine. After 6 weeks' exposure, blueberries (bilberries) and an extract from the common milk thistle were found to exert a highly significant inhibition of cell proliferation induced by snus in the rat forestomach epithelium, indicating a potential protection with respect soft tissue changes in the human oral cavity.

Risk Factors for Early-Onset and Very-Early-Onset Pancreatic Adenocarcinoma: A Pancreatic Cancer Case-Control Consortium (PanC4) Analysis

OBJECTIVES

While pancreatic cancer (PC) most often affects older adults, to date, there has been no comprehensive assessment of risk factors among PC patients younger than 60 years.

METHODS

We defined early-onset PC (EOPC) and very-early-onset PC (VEOPC) as diagnosis of PC in patients younger than 60 and 45 years, respectively. We pooled data from 8 case-control studies, including 1954 patients with EOPC and 3278 age- and sex-matched control subjects. Logistic regression analysis was performed to identify associations with EOPC and VEOPC.

RESULTS

Family history of PC, diabetes mellitus, smoking, obesity, and pancreatitis were associated with EOPC. Alcohol use equal to or greater than 26 g daily also was associated with increased risk of EOPC (odds ratio, 1.49; 95% confidence interval, 1.21-1.84), and there appeared to be a dose- and age-dependent effect of alcohol on risk. The point estimate for risk of VEOPC was an odds ratio of 2.18 (95% confidence interval, 1.17-4.09).

CONCLUSIONS

The established risk factors for PC, including smoking, diabetes, family history of PC, and obesity, also apply to EOPC. Alcohol intake appeared to have an age-dependent effect; the strongest association was with VEOPC.

Smokeless tobacco-associated cancers: A systematic review and meta-analysis of Indian studies

The International Agency for Research on Cancer (IARC) has concluded that there is sufficient evidence in humans for the carcinogenicity of smokeless tobacco (SLT) for mouth, oesophagus and pancreas, based largely on Western studies. We wanted to confirm this by conducting a systematic review using Indian studies because India faces the biggest brunt of SLT-attributable health effects. A systematic search was conducted for published and unpublished studies. Two authors independently reviewed the studies and extracted data. Summary odds ratio (OR) for each cancer type was calculated using fixed and random effects model. The population attributable fraction (PAF) method was used to calculate the attributable burden of incident cases. A significant association was found for oral-5.55 (5.07, 6.07), pharyngeal-2.69 (2.28, 3.17), laryngeal-2.84 (2.18, 3.70), oesophageal-3.17 (2.76, 3.63) and stomach-1.26 (1.00, 1.60) cancers. But in random effects model, laryngeal-1.79 (0.70, 4.54) and stomach-1.31 (0.92, 1.87) cancers became non-significantly associated. Gender-wise analysis revealed that women had a higher risk (OR = 12.0 vs. 5.16) of oral but a lower risk (1.9 vs. 4.5) of oesophageal cancer compared with men. For oral cancer, studies that adjusted for smoking, alcohol and other factors reported a significantly lower OR compared with studies that adjusted for smoking only or smoking and alcohol only (3.9 vs. 8.4). The annual number of attributable cases was calculated as 49,192 (PAF = 60%) for mouth, 14,747 (51%) for pharynx, 11,825 (40%) for larynx, 14,780 (35%) for oesophagus and 3,101 (8%) for stomach.

Cigarette smoking and risk of pancreatic cancer: a clinic-based case-control study in the San Francisco Bay Area

PURPOSE

Cigarette smoking is an established risk factor for pancreatic cancer (PC). We examined the association between cigarette smoking and PC in a San Francisco Bay Area clinic-based, case-control study.

METHODS

A total of 536 cases and sex and age frequency-matched controls (n = 869) were recruited predominately from the University of California San Francisco (UCSF) medical clinics between 2006 and 2011. Participants were interviewed in-person using structured questionnaires. Adjusted odds ratios (ORs) were computed.

RESULTS

Forty-eight percent of cases and controls reported never having smoked cigarettes; 39% of cases and 40% of controls were former smokers; 13% of cases and 12% of controls were current smokers. No association was found for either former (OR = 0.85, 95% confidence interval [CI] = 0.66-1.1) or current cigarette smoking (men: OR = 1.0, 95% CI = 0.60-1.7; women: OR = 1.2, 95% CI = 0.73-2.1). No dose-response relationships were detected with number of cigarettes/day, smoking intensity, duration, or years since last smoked. Comparisons with a 1995-1999 population-based UCSF study demonstrated a significantly increased proportion of never smokers in this study (P < .001).

CONCLUSIONS

This study revealed no significant associations between cigarette smoking and PC in the San Francisco Bay Area during 2006-2011. Data suggest a reduction in the duration of smoking within the referral population.

Hereditary Pancreatic Cancer Syndromes

Despite decades of scientific and clinical research, pancreatic ductal adenocarcinoma (PDAC) remains a lethal malignancy. The clinical and pathologic features of PDAC, specifically the known environmental and genetic risk factors, are reviewed here with special emphasis on the hereditary pancreatic cancer (HPC) syndromes. For these latter conditions, strategies are described for their identification, for primary and secondary prevention in unaffected carriers, and for disease management in affected carriers. Nascent steps have been made toward personalized medicine based on the rational use of screening, tumor subtyping, and targeted therapies; these have been guided by growing knowledge of HPC syndromes in PDAC.

Comparing outcomes of stereotactic body radiotherapy with intensity-modulated radiotherapy for patients with locally advanced unresectable pancreatic cancer

OBJECTIVES

Survival in patients with locally advanced unresectable pancreatic cancer (LAUPC) is poor, and local recurrence continues to be a major problem in the management of this disease. Radiotherapy (RT) using different RT techniques, including intensity-modulated radiotherapy (IMRT) and stereotactic body radiation therapy (SBRT), may lead to different clinical outcomes for patients with LAUPC. Here, we compared SBRT with IMRT for patients with LAUPC with respect to survival rate, local control (LC) rate, and toxicity-related dose distribution.

MATERIALS AND METHODS

This retrospective study from March 2007 to March 2011 included 41 patients with LAUPC who were divided into two groups, with 20 patients receiving SBRT and 21 patients receiving IMRT. The median follow-up time was 16 months.

RESULTS

For the IMRT and SBRT groups, the median survival times were 13 and 20 months, and 1-year overall survival (OS) rates were 70.7 and 80.0%, respectively. There was no difference in OS between the two RT techniques. RT with SBRT showed significantly better local disease-free survival than IMRT for patients with LAUPC. Tobacco use had a borderline effect on LC. Thus, further statistical analysis showed that patients who used tobacco had better LC after receiving SBRT than IMRT.

CONCLUSION

SBRT improved LC for LAUPC patients and had similar radiation toxicity compared with IMRT. Further study is required to define the effects of administered radiation dose and fractionation, as well as to further expand the sample size, to use a prospective study, and to observe the long-term efficacy of these techniques.

Risk factors for pancreatic cancer: a summary review of meta-analytical studies

BACKGROUND

The aetiology of pancreatic cancer (PC) has been extensively studied and is the subject of numerous meta-analyses and pooled analyses. We have summarized results from these pooled and meta-analytical studies to estimate the fraction of PCs attributable to each of the identified risk factors.

METHODS

Using a comprehensive strategy, we retrieved 117 meta-analytical or pooled reports dealing with the association between specific risk factors and PC risk. We combined estimates of relative risk and estimates of exposure to calculate the fraction of PCs caused or prevented by a particular exposure.

RESULTS

Tobacco smoking ('strong' evidence) and Helicobacter pylori infection ('moderate' evidence) are the major risk factors associated with PC, with respective estimated population attributable fractions of 11-32% and 4-25%. The major protective factors are history of allergy ('strong' evidence) and increasing fruit or folate intake ('moderate' evidence), with respective population preventable fractions of 3-7% and 0-12%.

CONCLUSIONS

We summarized results of 117 meta-analytical or pooled data reports dealing with 37 aetiological exposures, to obtain robust information about the suspected causes of PC. By combining these estimates with their prevalences in the population, we calculated population attributable or population preventable fractions. About two-thirds of the major risk factors associated with PC are potentially modifiable, affording a unique opportunity for preventing one of our deadliest cancers.

The association between smokeless tobacco use and pancreatic adenocarcinoma: a systematic review

BACKGROUND

Smokeless tobacco is a possible risk factor for developing pancreatic adenocarcinoma. This systematic review addressed the question: Is there an association between smokeless tobacco use and pancreatic adenocarcinoma diagnosis?

METHODS

Five electronic databases, grey literature, and citations of relevant articles were searched to identify studies. Six researchers double-reviewed records for inclusion in the review. The information extracted from these studies was selected using criteria outlined in the Newcastle-Ottawa Quality Assessment Scale for observational studies. A qualitative synthesis of included studies was performed.

RESULTS

The search of electronic databases resulted in a total of 1747 citations. Eleven studies met the inclusion criteria for this review, including three cohort studies, seven case control studies and one study that pooled data from multiple case-control studies. Studies were heterogeneous in their assessment of exposure intensity and ascertainment of outcomes. Quality of the studies varied. Existing investigations of the association of interest appear to exhibit several types of biases including selection bias, information bias and bias in the analysis.

CONCLUSION

The association between smokeless tobacco use and pancreatic adenocarcinoma is inconclusive. More definitive conclusions regarding this relationship await the results of more methodologically rigorous epidemiologic studies.

Biomarkers of exposure among U.S. cigar smokers: an analysis of 1999-2012 National Health and Nutrition Examination Survey (NHANES) data

BACKGROUND

Cigar consumption is increasing in the United States, but little information is available about exposure to toxic constituents from cigar smoking.

METHODS

We conducted a cross-sectional analysis of biomarkers of tobacco exposure among 25,522 participants from the National Health and Nutrition Examination Survey (NHANES, 1999-2012). The biomarkers analyzed were serum cotinine, urinary 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), blood lead, blood cadmium, and urinary arsenic. We calculated geometric mean concentrations for each biomarker by tobacco use category and geometric mean ratios controlling for demographic factors.

RESULTS

Cigar smokers had higher cotinine, NNAL, and lead concentrations than nontobacco users. The geometric mean concentration [95% confidence interval (CI)] of cotinine for primary cigar smokers (i.e., current cigar/never cigarette smokers) was 6.2 (4.2-9.2) ng/mL versus 0.045 (0.043-0.048) ng/mL for nontobacco users, and the NNAL concentration was 19.1 (10.6-34.3) pg/mg creatinine for primary cigar smokers versus 1.01 (0.95-1.07) pg/mg creatinine for nontobacco users. Secondary cigar smokers (i.e., current cigar/former cigarette smokers) and dual cigar/cigarette smokers had higher cadmium concentrations than nontobacco users. Cigar smoking was associated with significantly higher concentrations of cotinine, NNAL, cadmium, and lead, after adjusting for demographic factors. Secondary cigar smokers had significantly higher cotinine and NNAL concentrations than primary cigar smokers. The NNAL concentrations in daily cigar smokers were comparable with those in daily cigarette smokers.

CONCLUSIONS

Cigar smokers have higher concentrations of several toxic and carcinogenic substances than nontobacco users.

IMPACT

Our results are consistent with epidemiologic evidence demonstrating cigar smoking as a cause of disease and premature death.

Physical activity and risk of pancreatic cancer in a central European multicenter case-control study

PURPOSE

Findings from epidemiological studies examining physical activity in relation to pancreatic cancer risk have suggested decreased risks for physical activity; however, the results are inconsistent.

METHODS

The association between occupational and leisure-time physical activity and risk of pancreatic cancer was examined among 826 pancreatic cancer cases and 930 age-, sex- and center-matched controls from a large multicenter central European study in Czech Republic and Slovakia recruited between 2004 and 2012. Data on physical activity including type and dose (frequency, intensity, and duration) were examined using multivariable-adjusted logistic regression models.

RESULTS

Occupational physical activity was not significantly associated with risk of pancreatic cancer [odds ratio (OR) 0.90, 95 % confidence interval (CI) 0.71-1.15]. A 35 % decrease in risk of pancreatic cancer was observed for regular leisure-time physical activity (OR 0.65, 95 % CI 0.52-0.87). The risk estimates were significant for low and moderate intensity of activity with the strongest protective effect among individuals who exercised during more than 40 weeks per year. The results for cumulated leisure-time physical activity assessed 1 year prior to diagnosis achieved the same level of risk reduction. In addition, stronger risk estimates for leisure-time physical activity were observed among women (men: OR 0.74, 95 % CI 0.54-1.01; women: OR 0.53, 95 % CI 0.37-0.75). The findings for female participants were stronger for intensity and frequency of leisure-time physical activity, in particular for light and moderate activity (OR 0.43, 95 % CI 0.25-0.75; and OR 0.57, 95 % CI 0.37-0.88, respectively).

CONCLUSION

These results provide evidence for a decreased risk of pancreatic cancer associated with regular leisure-time physical activity.

Cross-species analysis of nicotine-induced proteomic alterations in pancreatic cells

Toxic compounds in tobacco, such as nicotine, may adversely affect pancreatic function. We aim to determine nicotine-induced protein alterations in pancreatic cells, thereby revealing links between nicotine exposure and pancreatic disease. We compared the proteomic alterations induced by nicotine treatment in cultured pancreatic cells (mouse, rat, and human stellate cells and human duct cells) using MS-based techniques, specifically SDS-PAGE (gel) coupled with LC-MS/MS and spectral counting. We identified thousands of proteins in pancreatic cells, hundreds of which were identified exclusively or in higher abundance in either nicotine-treated or untreated cells. Interspecies comparisons of stellate cell proteins revealed several differentially abundant proteins (in nicotine treated versus untreated cells) common among the three species. Proteins appearing in all nicotine-treated stellate cells include amyloid beta (A4), procollagen type VI alpha 1, integral membrane protein 2B, and toll-interacting protein. Proteins that were differentially expressed upon nicotine treatment across cell lines were enriched in certain pathways, including nicotinic acetylcholine receptor, cytokine, and integrin signaling. At this analytical depth, we conclude that similar pathways are affected by nicotine, but alterations at the protein level among stellate cells of different species vary. Further interrogation of such pathways will lead to insights into the potential effect of nicotine on pancreatic cells at the biomolecular level and the extension of this concept to the effect of nicotine on pancreatic disease.

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.

Tobacco harm reduction: opportunity and opposition

Purpose

This paper aims to provide a brief summary of the effectiveness and efficacy of tobacco harm reduction (THR). THR is the substitution for cigarettes of low‐risk alternatives, including Swedish or American‐style smokeless tobacco, pharmaceutical nicotine products, and electronic cigarettes. The paper then very briefly summarizes the current social and political situation regarding THR.

Design/methodology/approach

This paper is a review of the evidence.

Findings

The risk from smoke‐free tobacco/nicotine products is so low as to be unmeasurable. For most smokers, adopting THR is a lower risk option than to trying to become nicotine abstinent. THR products have been widely adopted in some populations, providing great public health benefits. There is currently an explosion of interest in electronic cigarettes. However, THR is a threat to the business model of the tobacco control industry, and so they are fighting hard to discourage it. Because they cannot admit their real motives for discouraging THR, anti‐THR activism is an entirely dishonest enterprise.

Practical implications

Tobacco harm reduction is the greatest untapped public health initiative in the developed world. It is more promising than further attempts to promote tobacco/nicotine abstinence. The future inevitably includes a large portion of the population using low‐risk tobacco/nicotine, but anti‐THR efforts might keep people smoking in the short run.

Originality/value

While most of the content of this paper is well known to experts on THR, many ostensible experts on health, as well as other opinion leaders and policy makers, are unaware of the truth.

Reducing harm from tobacco use

If current trends in smoking prevalence continue, even with the implementation of enhanced tobacco control measures, millions of smokers will continue to fall ill and die as a direct result of their smoking. Many of these will be from the most deprived groups in society - smoking continues to be one of the strongest drivers of health inequalities. The personal costs of this morbidity and mortality, as well as costs to business and the economy, are unequalled and will therefore remain high for several decades to come. However, there is an addition to the tobacco control armoury that could have a marked impact on public health, but it requires radical action to be taken. This would be to embrace harm reduction, but this approach is as controversial in the case of tobacco as it is in the case of illicit drugs from where it derives. However, harm reduction remains the Cinderella of the three major strategies for reducing smoking-related harm, the others being prevention and cessation. Here we make the case that harm reduction has an important role to play in reducing the health burden of tobacco use.

The chemical composition of smokeless tobacco: a survey of products sold in the United States in 2006 and 2007

Selected toxicant concentrations and other chemical measures have been determined for 43 U.S. smokeless tobacco products sold in 2006 and 2007. Products evaluated included moist snuff, dry snuff, loose leaf, plug, dissolvable and snus tobacco brands. Reference products available for scientific research purposes and eleven Swedish products were also evaluated and compared to the commercial products studied. Chemical endpoints determined included benzo[a]pyrene (B[a]P), N'-nitrosonornicotine (NNN), N'-nitrosoanatabine (NAT), N'-nitrosoanabasine (NAB), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), N-Nitrosodimethylamine (NDMA), nitrite, cadmium, lead, arsenic, nickel, chromium, chloride, water, pH and nicotine. Different toxicant profiles were observed for the products studied, with snus tobacco brands generally containing relatively low concentrations of B[a]P and tobacco specific nitrosamines (TSNAs) compared to other moist snuffs. Smokeless tobacco reference product toxicant profiles were similar to corresponding commercial products, with the exception of the TSNA content of the dry snuff reference material. TSNA concentrations observed for all commercial products were lower than historically reported values, likely reflecting changes in product shelf life, tobacco curing practices and, possibly, product blend formulations during the last 20-30 years. The survey results summarized provide a temporal point of comparison with future data anticipated from FDA "harmful and potentially harmful constituents in tobacco products" reporting.

Pancreatitis and pancreatic cancer risk: a pooled analysis in the International Pancreatic Cancer Case-Control Consortium (PanC4)

BACKGROUND

Pancreatitis is a known risk factor for pancreatic cancer; however, an unknown fraction of the disease is thought to be a consequence of tumor-related duct obstruction.

PATIENTS AND METHODS

A pooled analysis of a history of pancreatitis and risk of pancreatic cancer was carried out considering the time interval between diagnoses and potential modification by covariates. Adjusted pooled odds ratios (ORs) and 95% confidence intervals (CIs) were estimated from 10 case-control studies (5048 cases of ductal pancreatic adenocarcinoma and 10,947 controls) taking part in the International Pancreatic Cancer Case-Control Consortium (PanC4).

RESULTS

The association between pancreatitis and pancreatic cancer was nearly three-fold at intervals of >2 years between diagnoses (OR: 2.71, 95% CI: 1.96-3.74) and much stronger at intervals of ≤2 years (OR: 13.56, 95% CI: 8.72-21.90) probably reflecting a combination of reverse causation and antecedent misdiagnosis of pancreas cancer as pancreatitis. The younger (<65 years) pancreatic cancer cases showed stronger associations with previous (>2 years) pancreatitis (OR: 3.91, 95% CI: 2.53-6.04) than the older (≥65 years) cases (OR: 1.68, 95% CI: 1.02-2.76; P value for interaction: 0.006).

CONCLUSIONS

Despite a moderately strong association between pancreatitis (diagnosed before >2 years) and pancreatic cancer, the population attributable fraction was estimated at 1.34% (95% CI: 0.612-2.07%), suggesting that a relatively small proportion of pancreatic cancer might be avoided if pancreatitis could be prevented.

Obesity and survival in population-based patients with pancreatic cancer in the San Francisco Bay Area

BACKGROUND

Obesity has been consistently associated with increased risk of pancreatic cancer incidence and mortality. However, studies of obesity and overall survival in patients with pancreatic cancer are notably lacking, especially in population-based studies.

METHODS

Active and passive follow-up were used to determine vital status and survival for 510 pancreatic cancer patients diagnosed from 1995 to 1999 in a large population-based case-control study in the San Francisco Bay Area. Survival rates were computed using Kaplan-Meier methods. Hazard ratios (HR) and 95 % confidence intervals (CI) were estimated in multivariable Cox proportional hazards models as measures of the association between pre-diagnostic obesity and pancreatic cancer survival.

RESULTS

An elevated hazard ratio of 1.3 (95 % CI, 0.91-1.81) was observed for obese [body mass index (BMI) ≥ 30] compared with normal range BMI (<25) patients. Associations between BMI and overall survival did not statistically significantly vary by known prognostic and risk factors (all p-interaction ≥0.18), yet elevated HRs consistently were observed for obese compared with normal BMI patients [localized disease at diagnosis (HR, 3.1), surgical resection (HR, 1.6), ever smokers (HR, 1.6), diabetics (HR, 3.3)]. Poor survival was observed among men, older patients, more recent and current smokers, whereas improved survival was observed for Asian/Pacific Islanders.

CONCLUSIONS

Our results in general provide limited support for an association between pre-diagnostic obesity and decreased survival in patients with pancreatic cancer. Patterns of reduced survival associated with obesity in some patient subgroups could be due to chance and require assessment in larger pooled studies.

Cigarette smoking and pancreatic cancer: an analysis from the International Pancreatic Cancer Case-Control Consortium (Panc4)

BACKGROUND

To evaluate the dose-response relationship between cigarette smoking and pancreatic cancer and to examine the effects of temporal variables.

METHODS

We analyzed data from 12 case-control studies within the International Pancreatic Cancer Case-Control Consortium (PanC4), including 6507 pancreatic cases and 12 890 controls. We estimated summary odds ratios (ORs) by pooling study-specific ORs using random-effects models.

RESULTS

Compared with never smokers, the OR was 1.2 (95% confidence interval [CI] 1.0-1.3) for former smokers and 2.2 (95% CI 1.7-2.8) for current cigarette smokers, with a significant increasing trend in risk with increasing number of cigarettes among current smokers (OR=3.4 for ≥35 cigarettes per day, P for trend<0.0001). Risk increased in relation to duration of cigarette smoking up to 40 years of smoking (OR=2.4). No trend in risk was observed for age at starting cigarette smoking, whereas risk decreased with increasing time since cigarette cessation, the OR being 0.98 after 20 years.

CONCLUSIONS

This uniquely large pooled analysis confirms that current cigarette smoking is associated with a twofold increased risk of pancreatic cancer and that the risk increases with the number of cigarettes smoked and duration of smoking. Risk of pancreatic cancer reaches the level of never smokers ∼20 years after quitting.

Effects of a Fact Sheet on beliefs about the harmfulness of alternative nicotine delivery systems compared with cigarettes

BACKGROUND

This study explored the value of providing information in a Fact Sheet to correct misperceptions about the relative harmfulness of nicotine replacement products (NRT) and smokeless tobacco (ST), when compared to cigarette smoking.

METHODS

Four convenience samples from different countries (Australia, UK, Sweden and USA) were surveyed concerning their beliefs about the relative harmfulness of smokeless tobacco and NRT. Study participants were given the Fact Sheet that explained that nicotine, as used by consumers, is not particularly harmful and explained why. They were resurveyed one week later regarding their beliefs about the relative harmfulness of smokeless tobacco and NRT and future intentions to use the products.

RESULTS

In all four samples knowledge increased by similar amounts and beliefs regarding the lower harmfulness of smokeless tobacco increased. However, misconceptions remained common and responses to belief measures were not always consistent. Likelihood of use of ST increased in all four samples after exposure to the Fact Sheet, but interest in NRT use only increased in the US sample.

CONCLUSIONS

A Fact Sheet such as this one can help address misconceptions about NRT and smokeless tobacco, at least in the short term. However, as is true of most educational interventions, exposure to a single educational session is not sufficient to overcome misperceptions that smokers have about the relative harmfulness of oral versus combustible forms of nicotine delivery.

Mechanisms for nicotine in the development and progression of gastrointestinal cancers

Long-term smoking is major risk factor for a variety of cancers, including those of the gastrointestinal (GI) tract. Historically, nicotine and its derivatives are well known for their role in addiction, and have more recently been documented for their carcinogenic role in a number of human cancers. The cellular and molecular pathways activated by nicotine mimic physiological and environmental carcinogenesis in cancers throughout the GI tract potentiating cancer growth and/or inducing the formation of cancer on their own. Thus, it is important to unlock the carcinogenic mechanisms induced by nicotine in these systems, and underscore nicotine's potential as an environmental hazard. This review outlines the specific pathways demonstrated to mediate nicotine's carcinogenic mechanism in the GI tract. The abundance of cell and animal evidence calls for increased epidemiologic and case-control evaluation of nicotine's role in cancer.

Non-cigarette tobacco products: what have we learnt and where are we headed?

A wide variety of non-cigarette forms of tobacco and nicotine exist, and their use varies regionally and globally. Smoked forms of tobacco such as cigars, bidis, kreteks and waterpipes have high popularity and are often perceived erroneously as less hazardous than cigarettes, when in fact their health burden is similar. Smokeless tobacco products vary widely around the world in form and the health hazards they present, with some clearly toxic forms (eg, in South Asia) and some forms with far fewer hazards (eg, in Sweden). Nicotine delivery systems not directly reliant on tobacco are also emerging (eg, electronic nicotine delivery systems). The presence of such products presents challenges and opportunities for public health. Future regulatory actions such as expansion of smoke-free environments, product health warnings and taxation may serve to increase or decrease the use of non-cigarette forms of tobacco. These regulations may also bring about changes in non-cigarette tobacco products themselves that could impact public health by affecting attractiveness and/or toxicity.

Alcohol consumption and pancreatic cancer: a pooled analysis in the International Pancreatic Cancer Case-Control Consortium (PanC4)

BACKGROUND

Heavy alcohol drinking has been related to pancreatic cancer, but the issue is still unsolved.

METHODS

To evaluate the role of alcohol consumption in relation to pancreatic cancer, we conducted a pooled analysis of 10 case-control studies (5585 cases and 11,827 controls) participating in the International Pancreatic Cancer Case-Control Consortium. We computed pooled odds ratios (ORs) by estimating study-specific ORs adjusted for selected covariates and pooling them using random effects models.

RESULTS

Compared with abstainers and occasional drinkers (< 1 drink per day), we observed no association for light-to-moderate alcohol consumption (≤ 4 drinks per day) and pancreatic cancer risk; however, associations were above unity for higher consumption levels (OR = 1.6, 95% confidence interval 1.2-2.2 for subjects drinking ≥ 9 drinks per day). Results did not change substantially when we evaluated associations by tobacco smoking status, or when we excluded participants who reported a history of pancreatitis, or participants whose data were based upon proxy responses. Further, no notable differences in pooled risk estimates emerged across strata of sex, age, race, study type, and study area.

CONCLUSION

This collaborative-pooled analysis provides additional evidence for a positive association between heavy alcohol consumption and the risk of pancreatic cancer.

Proton pump inhibitors and histamine-2-receptor antagonists and pancreatic cancer risk: a nested case-control study

BACKGROUND

The relationship between use of proton pump inhibitors (PPIs) and histamine-2-receptor antagonists (H(2)RAs) and pancreatic cancer risk has yet to be examined. Data from a range of studies suggest biologically plausible mechanisms, whereby these drugs (or the conditions for which they are prescribed) may affect pancreatic cancer risk. The objective of this study was to investigate the relationship between use of PPIs/H(2)RAs and pancreatic cancer risk.

METHODS

A nested case-control study was conducted within the UK general practice research database (GPRD). Cases had a diagnosis of exocrine pancreatic cancer and controls were matched to cases on general practice site, sex and year of birth. Exposure to PPIs and to H(2)RAs since entry into GPRD until 2 years before the diagnosis date (corresponding date in controls) and in the 5 years before the diagnosis date were separately assessed. Conditional logistic regression analyses were used to generate odds ratios (ORs) and 95% confidence intervals (CIs) associated with PPI or H(2)RA use compared with nonuse.

RESULTS

Ever use of PPIs since entry into the GPRD (excluding the 2 years prior to diagnosis) was not associated with risk of pancreatic cancer; OR (95% CI) 1.02 (0.85-1.22). Neither the dose nor the duration of PPI or H(2)RA use was associated with pancreatic cancer risk. No consistent patterns of association were seen when cumulative exposure (dose and duration) to these drugs was examined separately or together.

CONCLUSION

PPI/H(2)RA use, in a UK population, was not associated with pancreatic cancer risk.

Perceptions of the relative harmfulness of snus among Norwegian general practitioners and their effect on the tendency to recommend snus in smoking cessation

INTRODUCTION

Research suggests that health risks associated with the use of Swedish moist snuff (snus) are considerably smaller than health risks associated with cigarette smoking. However, erroneous ideas of approximately equal harm from snus and cigarettes are common in the general population. General practitioners (GPs) have a crucial role in giving information about health and risk to patients, and the objective of this study was to measure their perceptions of the relative harmfulness of cigarettes and snus and how these perceptions related to their tendency to recommend snus as a smoking cessation aid.

METHODS

Approximately 900 GPs completed a questionnaire in 2008 (response rate about 45%). Perceived relative risk was measured by the question: "In terms of health risks, how do you think daily use of snus compares to daily use of cigarettes?" Answer categories ranged from "snus is much more harmful" to "snus is much less harmful."

RESULTS

Only 36% of the GPs believed that snus was much less harmful than cigarettes. More than 15% believed that snus was equally or more harmful than cigarettes. GPs who rated snus as much less harmful more often recommended snus as an aid in smoking cessation.

CONCLUSIONS

Almost two thirds of the GPs had beliefs about the relative risk of snus and cigarettes that were at odds with scientific consensus. The associated limitations in disseminated information about snus as a possible quitting aid can be understood as an unexploited intervention potential.

Cholecystectomy and risk of pancreatic cancer: a meta-analysis of observational studies

OBJECTIVE

Data from epidemiological studies related to the association of cholecystectomy and pancreatic cancer (PaC) risk are inconsistent. We conducted a meta-analysis of observational studies to explore this relationship.

METHODS

We identified studies by a literature search of Medline (from 1 January 1966) and EMBASE (from 1 January 1974), through 30 June 2011, and by searching the reference lists of pertinent articles. Summary relative risks with their 95% confidence intervals were calculated with a random-effects model. Between-study heterogeneity was assessed using Cochran's Q statistic and the I (2).

RESULTS

A total of 18 studies (10 case-control studies, eight cohort studies) were included in this meta-analysis. Analysis of these 18 studies found that cholecystectomy was associated with a 23% excess risk of PaC (SRR = 1.23, 95% CI = 1.12-1.35), with moderate heterogeneity among these studies (p (heterogeneity) = 0.006, I (2) = 51.0%). Sub-grouped analyses revealed that the increased risk of PaC was independent of geographic location, gender, study design and confounders. There was no publication bias in the current meta-analysis.

CONCLUSIONS

The results of this meta-analysis suggest that individuals with a history of cholecystectomy may have an increased risk of pancreatic cancer.