Juhua Luo

Oral use of Swedish moist snuff (snus) and risk for cancer of the mouth, lung, and pancreas in male construction workers: a retrospective cohort study.

BACKGROUNDnAlthough classified as carcinogenic, snuff is used increasingly in several populations. Scandinavian moist snuff (snus) has been proposed as a less harmful alternative to smoking, but precise data on the independent associations of snus use with site-specific cancers are sparse. We aimed to assess the risks for cancer of the oral cavity, lung, and pancreas.nnnMETHODSnDetailed information about tobacco smoking and snus use was obtained from 279 897 male Swedish construction workers in 1978-92. Complete follow-up until end of 2004 was accomplished through links with population and health registers. To distinguish possible effects of snus from those of smoking, we focused on 125 576 workers who were reported to be never-smokers at entry. Adjusted relative risks were derived from Cox proportional hazards regression models.nnnFINDINGSn60 cases of oral, 154 of lung, and 83 of pancreatic cancer were recorded in never-smokers. Snus use was independently associated with increased risk of pancreatic cancer (relative risk for ever-users of snus 2.0; 95% CI 1.2-3.3, compared with never-users of any tobacco), but was unrelated to incidence of oral (0.8, 95% CI 0.4-1.7) and lung cancer (0.8, 0.5-1.3).nnnINTERPRETATIONnUse of Swedish snus should be added to the list of tentative risk factors for pancreatic cancer. We were unable to confirm any excess of oral or lung cancer in snus users.

Cigarette Smoking and Pancreatic Cancer: A Pooled Analysis From the Pancreatic Cancer Cohort Consortium

Smoking is an established risk factor for pancreatic cancer; however, detailed examination of the association of smoking intensity, smoking duration, and cumulative smoking dose with pancreatic cancer is limited. The authors analyzed pooled data from the international Pancreatic Cancer Cohort Consortium nested case-control study (1,481 cases, 1,539 controls). Odds ratios and 95% confidence intervals were calculated by using unconditional logistic regression. Smoking intensity effects were examined with an excess odds ratio model that was linear in pack-years and exponential in cigarettes smoked per day and its square. When compared with never smokers, current smokers had a significantly elevated risk (odds ratio (OR) = 1.77, 95% confidence interval (CI): 1.38, 2.26). Risk increased significantly with greater intensity (> or =30 cigarettes/day: OR = 1.75, 95% CI: 1.27, 2.42), duration (> or =50 years: OR = 2.13, 95% CI: 1.25, 3.62), and cumulative smoking dose (> or =40 pack-years: OR = 1.78, 95% CI: 1.35, 2.34). Risk more than 15 years after smoking cessation was similar to that for never smokers. Estimates of excess odds ratio per pack-year declined with increasing intensity, suggesting greater risk for total exposure delivered at lower intensity for longer duration than for higher intensity for shorter duration. This finding and the decline in risk after smoking cessation suggest that smoking has a late-stage effect on pancreatic carcinogenesis.

The incidence of tonsillar cancer in Sweden is increasing

Conclusions: The incidence of tonsillar cancer in Sweden is increasing, particularly among men. Risk factors other than smoking may have contributed to the observed secular trend in men. In women, however, smoking can be a part of the explanation. Further studies to look at changes in other environmental factors, such as human papilloma virus (HPV) infection, are clearly warranted. Objectives: Head and neck cancer is related to smoking habits and smoking has decreased substantially during the last 30 years in Sweden. However, there is suspicion that the incidence of tonsillar cancer has increased in the last 30 years as it has in the USA and Finland, in spite of reduced prevalence of known risk factors. The time trends of oral and oropharygeal cancer have been studied in Sweden, but not tonsillar cancer specifically. Subjects and methods: We used the Swedish Cancer Registry to assess the secular trend of incidence of tonsillar cancer in Sweden since 1960. For comparison we investigated the incidence of other oral cancers and lung cancer, which are also smoking-related. The prevalence of smoking was investigated for reference. Age-standardized incidence rates were calculated and linear regression was used to evaluate secular trends. Results: The incidence of tonsillar cancer increased by 2.6% per year in men and 1.1% in women. No similar increase was seen in the other oral cancers. For lung cancer there was a decrease in the incidence in men, but in women the incidence is still increasing.

Body mass index, physical activity and the risk of pancreatic cancer in relation to smoking status and history of diabetes: a large-scale population-based cohort study in Japan–The JPHC study

ObjectiveThe effects of BMI and physical activity on the risk of pancreatic cancer were investigated in a large population-based cohort study in Japan (JPHC study). In particular, we explored how these effects were influenced by smoking status and a history of diabetes.MethodsIn total, 99,670 participants (47,499 men, and 52,171women) were followed for an average of 11xa0years through the end of 2003. Hazard ratios (HR) and their 95% confidence intervals (CI) were estimated by Cox proportional hazards models.ResultsA total of 224 incident cases (128 men, 96 women) of pancreatic cancer were identified. A statistically significant excess risk of pancreatic cancer was associated with current smoking (HRxa0=xa01.8, CI 1.1–3.0) and a history of diabetes (HRxa0=xa02.1, CI 1.3–3.5) among men. A similar increase in risk associated with current smoking (HRxa0=xa02.0, CI 0.9–4.4) and diabetes (HRxa0=xa01.5, CI 0.7–3.5) was also seen among women. BMI was inversely associated with risk of pancreatic cancer among men, especially among current male smokers or diabetes patients, but no association was found among women. Leisure-time physical activity was not associated with risk in either men or women.ConclusionsOur study confirms the association between cigarette smoking, history of diabetes and increased risk of pancreatic cancer. However, our data suggest that the association between BMI and risk of pancreatic cancer in this Japanese population may be different from that in Western populations.

Secular trends of nasopharyngeal carcinoma incidence in Singapore, Hong Kong and Los Angeles Chinese populations, 1973-1997

Nasopharyngeal carcinoma (NPC) is a rare cancer in most parts of world, but rather common in Southern China and Southeast Asia. This study used IARC published datasets to explore the secular trends of incidence rates of NPC among different Chinese populations in Singapore, Hong Kong and Los Angeles, over the time period 1973–1997. We observed great disparity in the risks and time trends of NPC in those selected Chinese populations. The highest risk was in Hong Kong where the incidence rates have declined rapidly throughout the whole study period in both males and females. For Singapore Chinese, the incidence rates also dropped recently in both genders, but the low incidence rates in Los Angeles Chinese have remained essentially unchanged over time. We further assessed the contribution of period and cohort effects to the observed trends in Hong Kong and Singapore populations through age-period-cohort modeling and found that an age-cohort model provided the best fit to the data in both populations, although for Singapore females a simple age-drift model fit the data well. There was a statistically significant decrease in the drop in incidence of NPC for cohorts born around 1940 in Hong Kong and 1958 in Singapore. This indicates that environmental and lifestyle changes play an important role in the declining incidence of NPC over time.

Green tea and coffee intake and risk of pancreatic cancer in a large-scale, population-based cohort study in Japan (JPHC study).

Pancreatic cancer is one of the most aggressive and treatment-refractory malignancies in humans. The most effective means of reducing pancreatic cancer mortality may be primary prevention. Although laboratory studies have demonstrated that green tea possesses anticancer activities, results from epidemiological studies have failed to show a consistent cancer-preventive effect. In addition, there is a lingering concern that coffee mighty increase the risk of pancreatic cancer although the most recent epidemiological studies showed no overall association between coffee and risk. Here, we examined the association between the drinking of green tea or coffee and the risk of pancreatic cancer in a large population-based cohort study in Japan (JPHC study). In total, 102u2009137 participants were followed for an average of 11 years through to the end of 2003. A total of 233 incident cases of pancreatic cancer were identified among 1u2009116u2009945 person-years of follow-up. Overall, the risk of pancreatic cancer was not associated with either green tea or coffee intake in our population, although a reduced risk was apparent among men who drank at least three cups of coffee per day compared with those who did not drink any or only rarely drank coffee. In conclusion, our findings support the idea that green tea or coffee consumption does not have a substantial impact on pancreatic cancer risk in general.

Risk of gastroesophageal cancer among smokers and users of Scandinavian moist snuff

Although Scandinavian moist snuff (“snus”), no doubt, is a safer alternative to smoking, there is limited evidence against an association with gastroesophageal cancers. In a retrospective cohort study, we investigated esophageal and stomach cancer incidence among 336,381 male Swedish construction workers who provided information on tobacco smoking and snus habits within a health surveillance program between 1971 and 1993. Essentially complete follow‐up through 2004 was accomplished through linkage to several nationwide registers. Multivariable Cox proportional hazards regression models estimated relative risks (RR) and 95% confidence intervals (CIs). Compared to never‐users of any tobacco, smokers had increased risks for adenocarcinoma (RR = 2.3, 95% CI 1.4–3.7) and squamous cell carcinoma (RR = 5.2, 95% CI 3.1–8.6) of the esophagus, as well as cardia (RR = 2.1, 95% CI 1.5–3.0) and noncardia stomach (RR = 1.3, 95% CI 1.2–1.6) cancers. We also observed excess risks for esophageal squamous cell carcinoma (RR = 3.5, 95% CI 1.6–7.6) and noncardia stomach cancer (RR = 1.4, 95% CI 1.1–1.9) among snus users who had never smoked. Although confounding by unmeasured exposures, and some differential misclassification of smoking, might have inflated the associations, our study provides suggestive evidence for an independent carcinogenic effect of snus.

Obesity and risk of pancreatic cancer among postmenopausal women: the Women's Health Initiative (United States)

A total of 138u2009503 women in the Womens Health Initiative in the United States were followed (for an average of 7.7 years) through 12 September 2005 to examine obesity, especially central obesity in relation to pancreatic cancer (n=251). Women in the highest quintile of waist-to-hip ratio had 70% (95% confidence interval 10–160%) excess risk of pancreatic cancer compared with women in the lowest quintile.

The risk of pancreatic cancer in patients with gastric or duodenal ulcer disease

Although Helicobacter pylori (H. pylori) seropositivity is linked to an excess risk of pancreatic cancer, the biologic mechanism is unknown. Gastric ulcer is primarily associated with corpus colonization of H. pylori, atrophic gastritis and formation of N‐nitrosamines. Duodenal ulcer is a marker of antral colonization, hyperacidity and uninhibited secretin release. We estimated relative risks for pancreatic cancer among patients with gastric or duodenal ulcer, based on a register‐based retrospective cohort study with 88,338 patients hospitalized for gastric ulcer and 70,516 patients for duodenal ulcer recorded in the Swedish Inpatient Register between 1965 and 2003. Following operation, the 14,887 patients who underwent gastric resection and 8,205 with vagotomy were analyzed separately. Multiple record‐linkages allowed complete follow‐up and identification of all incident cases of pancreatic cancer until December 31, 2003. Standardized incidence ratios (SIRs) estimated relative risks. During years 3–38 of follow‐up, we observed a 20% excess risk (95% confidence interval [CI] 10–40%) for pancreatic cancer among unoperated gastric ulcer patients. The excess increased to 50% (95% CI 10–110%) 15 years after first hospitalization (p for trend = 0.03). SIR was 2.1 (95% CI 1.4–3.1) 20 years after gastric resection. Unoperated duodenal ulcer was not associated with pancreatic cancer risk, nor was vagotomy. Our results lend indirect support to the nitrosamine hypothesis, but not to the hyperacidity hypothesis in the etiology of pancreatic cancer.

Interpreting trends of pancreatic cancer incidence and mortality: a nation-wide study in Sweden (1960-2003)

ObjectiveWe investigated temporal trends of pancreatic cancer in Sweden measured with suboptimal sensitivity and specificity both by incidence and by mortality rates.Methods46,257 incident cases of pancreatic cancer from the Swedish Cancer Register and 53,686 mortality cases from the Causes of Death Register during 1960–2003 were used to calculate age-standardized incidence or mortality rates. We further assessed the impact of changes in diagnostic practice on the observed trends, and investigated the effect of calendar period and birth cohort by age-period-cohort modeling.ResultsOverall, the pattern of trends in age-adjusted rates of pancreatic cancer was similar irrespective of whether incidence or mortality was used. The age-adjusted rates of pancreatic cancer increased during the first decade and then peaked for both sexes (the male peak occurred in the early 1970s and the female peak in the1980s) followed by a steady decline in both groups. An age-period model provided the best fit to the observed trends among patients diagnosed at ages 35–74 in both sexes.ConclusionThe close agreement between the incidence and mortality and the gender disparity suggest a true decline in pancreatic cancer incidence in recent years in Sweden, and gender-specific trends in exposure to environmental risk factors.