Smoking and the risk of endometrial cancer: results from the Nurses' Health Study

An inverse association between smoking and endometrial cancer has generally been observed, primarily among current smokers. To assess this association, we analyzed data from the prospective Nurses' Health Study. From 1976 to 2000, 702 cases of invasive endometrial cancer were identified during 1.8 million person-years of follow-up. Smoking status was assessed in 1976 and updated every 2 years. Cox proportional hazards models were used to calculate multivariate relative risks (RRs), controlling for endometrial cancer risk factors. Compared to never smokers, the multivariate RR of endometrial cancer was significantly lower among both current smokers (RR = 0.63; 95% CI = 0.50-0.79) and past smokers (RR = 0.73; 95% CI = 0.62-0.87). When additionally adjusting for body mass index (BMI), the RR for current smokers was attenuated (RR = 0.72; 95% CI = 0.57-0.90), but the RR for past smokers did not change. Risk was lower among women who smoked 35 or more cigarettes a day (RR = 0.60; 95% CI = 0.39-0.91) and among those who smoked for 40 or more years (RR = 0.63; 95% CI = 0.45-0.87). Tests for trend, which excluded never smokers, were not statistically significant for any of the smoking variables analyzed. These data indicate that both current and past smoking are associated with a lower risk of endometrial cancer. The findings provide insight into disease etiology and suggest that the influence of smoking on endometrial cancer risk occurs even in early adulthood, is long-lasting, and may not be attributed solely to short-term hormonal modulation.     

Smoking and survival after breast cancer diagnosis

We examined whether a history of smoking is associated with an increased risk of death from any cause or from breast cancer, among women diagnosed with breast cancer. This was a prospective observational study among 5,056 women from the Nurses' Health Study with Stages I-III invasive breast cancer diagnosed between 1978 and 2002 and for whom we had information on smoking, and who were followed until January 2002 or death, whichever came first. Subjects were classified as current, former or never smokers based upon smoking status at the biennial questionnaire immediately preceding the breast cancer diagnosis. In multivariate-adjusted analyses, compared with never smokers, women who were current smokers had a 43% increased adjusted relative risk (RR) [95% confidence interval (95% CI): 1.24-1.65] of death from any cause. A strong linear gradient was observed with the number of cigarettes per day smoked, p-trend <0.0001; the RR (95% CI) for 1-14, 15-24 and 25 or more cigarettes per day was 1.27 (1.01-1.61), 1.30 (1.08-1.57) and 1.79 (1.47-2.19). In contrast, there was no association with current smoking and breast cancer death; the RR (95% CI) was 1.00 (0.83-1.19). Current and past smokers were more likely than never smokers to die from primary lung cancer, chronic obstructive pulmonary disease and other lung diseases. We conclude that a history of smoking increased mortality following diagnosis with breast cancer, but did not increase mortality from breast cancer.     

Environmental tobacco smoke and lung cancer mortality in the American Cancer Society's Cancer Prevention Study II

Environmental tobacco smoke (ETS) has been classified as a human lung carcinogen by the United States Environmental Protection Agency (EPA), based both on the chemical similarity of sidestream and mainstream smoke and on slightly higher lung cancer risk in never-smokers whose spouses smoke compared with those married to nonsmokers. We evaluated the relation between ETS and lung cancer prospectively in the US, among 114,286 female and 19,549 male never-smokers, married to smokers, compared with about 77,000 female and 77,000 male never-smokers whose spouses did not smoke. Multivariate analyses, based on 247 lung cancer deaths, controlled for age, race, diet, and occupation. Dose-response analyses were restricted to 92,222 women whose husbands provided complete information on cigarette smoking and date of marriage. Lung cancer death rates, adjusted for other factors, were 20 percent higher among women whose husbands ever smoked during the current marriage than among those married to never-smokers (relative risk [RR]=1.2, 95 percent confidence interval [CI]=0.8-1.6). For never-smoking men whose wives smoked, the RR was 1.1 (CI=0.6-1.8). Risk among women was similar or higher when the husband continued to smoke (RR=1.2, CI=0.8-1.8), or smoked 40 or more cigarettes per day (RR=1.9, CI=1.0-3.6), but did not increase with years of marriage to a smoker. Most CIs included the null. Although generally not statistically significant, these results agree with the EPA summary estimate that spousal smoking increases lung cancer risk by about 20 percent in never-smoking women. Even large prospective studies have limited statistical power to measure precisely the risk from ETS.     

Cigarette smoking,use of other tobacco products and stomach cancer mortality in US adults: The Cancer Prevention Study II

Cigarette smoking is associated with increased risk of stomach cancer in many studies but there are limited data on this relationship in women and on risk associated with use of tobacco products other than cigarettes. We examined stomach cancer death rates in relation to cigarette smoking in women and use of cigarette, cigar, pipe, or smokeless tobacco in men in a nationwide prospective mortality study in the United States (US). Cohort follow-up from 1982-96 identified 996 and 509 stomach cancer deaths among 467,788 men and 588,053 women, respectively. Cox proportional hazards models were fitted to estimate rate ratios (RR) and 95% confidence intervals (CI) using non-users of tobacco as the referent group. Multivariate-adjusted RRs were the highest for men who currently smoked cigars (RR = 2.29, 95% CI = 1.49-3.51) or cigarettes (RR = 2.16, 95% CI = 1.75-2.67) and both increased with smoking duration. Women who currently (RR = 1.49, 95% CI = 1.18-1.88) or formerly (RR = 1.36, 95% CI = 1.08-1.71) smoked cigarettes were at significantly increased risk, as were men who formerly smoked cigarettes (RR = 1.55, 95% CI = 1.28-1.88), or currently (RR = 1.81, 95% CI = 1.40-2.35) or formerly (RR: 1.57, 95% CI = 1.22-2.03) used more than one type of tobacco. Men who reported a history of chronic indigestion or gastroduodenal ulcer had substantially higher mortality rates associated with current cigarette (RR = 3.45, 95% CI = 2.05-5.80) or cigar (RR = 8.93, 95% CI = 4.02-19.90) smoking, as did men who were current aspirin users. If causal, the estimated proportion of stomach cancer deaths attributable to tobacco use would be 28% in US men and 14% in women. We conclude that prolonged use of tobacco products is associated with increased stomach cancer mortality in men and women. The accumulated evidence from this and other studies support reconsidering stomach cancer as a tobacco-related cancer.     

Prospective study of fruit and vegetable consumption and risk of lung cancer among men and women

BACKGROUND: Diets high in fruits and vegetables have been shown to be associated with a lower risk of lung cancer. beta-Carotene was hypothesized to be largely responsible for the apparent protective effect, but this hypothesis was not supported by clinical trials. METHODS: We examined the association between lung cancer risk and fruit and vegetable consumption in 77 283 women in the Nurses' Health Study and 47 778 men in the Health Professionals' Follow-up Study. Diet was assessed with the use of a food-frequency questionnaire that included 15 fruits and 23 vegetables. We used logistic regression models to estimate relative risks (RRs) of lung cancer within each cohort. All statistical tests were two-sided. RESULTS: We documented 519 lung cancer cases among the women and 274 among the men. Total fruit and vegetable consumption was associated with a modestly lower risk of lung cancer among the women but not among the men. The RR for the highest versus lowest quintile of intake was 0.79 (95% confidence interval [CI] = 0.59-1.06) among the women and 1.12 (95% CI = 0.74-1.69) among the men after adjustment for smoking status, quantity of cigarettes smoked per day, time since quitting smoking, and age at initiation of smoking. However, total fruit and vegetable consumption was associated with a lower risk of lung cancer among never smokers in the combined cohorts, although the reduction was not statistically significant (RR = 0.63; 95% CI = 0.35-1.12 in the highest tertile). CONCLUSION: Higher fruit and vegetable intakes were associated with lower risks of lung cancer in women but not in men. It is possible that the inverse association among the women remained confounded by unmeasured smoking characteristics, although fruits and vegetables were protective in both men and women who never smoked.     

Cigarette smoking and colorectal cancer mortality in the cancer prevention study II

BACKGROUND: Recent studies suggest that long-term cigarette smoking is associated with an increased risk of colorectal cancer. Whether the association is causal or due to confounding remains unclear. METHODS: We examined cigarette smoking in relation to colorectal cancer mortality, evaluating smoking duration and recency and controlling for potential confounders in the Cancer Prevention Study II. This prospective nationwide mortality study of 1 184 657 adults (age > or =30 years) was begun by the American Cancer Society in 1982. After exclusions, our analytic cohort included 312 332 men and 469 019 women, among whom 4432 colon or rectal cancer deaths occurred between 1982 and 1996 among individuals who were cancer free in 1982. Rate ratios (RRs) and 95% confidence intervals (CIs) were estimated by fitting Cox proportional hazards models. All statistical tests were two-sided. RESULTS: Multivariate-adjusted colorectal cancer mortality rates were highest among current smokers, were intermediate among former smokers, and were lowest in lifelong nonsmokers. The multivariate-adjusted RR (95% CI) for current compared with never smokers was 1.32 (1.16-1.49) among men and 1.41 (1.26-1.58) among women. Increased risk was evident after 20 or more years of smoking for men and women combined as compared with never smokers. Risk among current and former smokers increased with duration of smoking and average number of cigarettes smoked per day; risk in former smokers decreased significantly with years since quitting. If the multivariate-adjusted RR estimates in this study do, in fact, reflect causality, then approximately 12% of colorectal cancer deaths among both men and women in the general U.S. population in 1997 were attributable to smoking. CONCLUSIONS: Long-term cigarette smoking is associated with increased risk of colorectal cancer mortality in both men and women. Clear reduction in risk is observed with early smoking cessation.     

吸烟与原发性肝癌关系的巢式病例对照研究

目的 分析吸烟与上海市区中老年男性原发性肝癌的关系.方法 应用巢式病例对照研究方法,对一个18 244名男性队列随访11年,以队列中213例新发肝癌患者作为病例组,按照患者年龄、采样日期、同居住区等配对条件,从队列中随机抽取1094名健康人作为对照组.使用配对Logistic回归分析,调整可能的混杂因素,估计吸烟对肝癌发生的危险度和95%可信区间(CI).结果 调整肝炎、肝硬化、胆石症或其他胆囊病史及乙型肝炎病毒感染等可能的混杂因素后,男性吸烟者患肝痛的危险性是不吸烟者的1.91倍(95%CI为1.28～2.86),日随着每天吸烟量、吸烟年限和吸烟包年数的增加而增加.每天吸烟≥20支者、吸烟≥40年者和吸烟37包年者患肝癌的相对危险度分别为2.16(95%CI为1.37～3.40)、2.14(95%CI为1.18～3.87)和2.12(95%CI为1.21～3.74).吸烟开始年龄越小,危险性越大,吸烟开始年龄<20岁者患肝癌的危险性为2.57(95%CI为1.50～4.40).结论 吸烟是上海市区男性原发性肝癌的危险因素.     

Cigar smoking in men and risk of death from tobacco-related cancers

BACKGROUND: Cigar consumption in the United States has increased dramatically since 1993, yet there are limited prospective data on the risk of cancer associated with cigar smoking. We examined the association between cigar smoking and death from tobacco-related cancers in a large, prospective cohort of U. S. men. METHODS: We used Cox proportional hazards models to analyze the relationship between cigar smoking at baseline in 1982 and mortality from cancers of the lung, oral cavity/pharynx, larynx, esophagus, bladder, and pancreas over 12 years of follow-up of the American Cancer Society's Cancer Prevention Study II cohort. A total of 137 243 men were included in the final analysis. Women were not included because we had no data on their cigar use. We excluded men who ever smoked cigarettes or pipes and adjusted all rate ratio (RR) estimates for age, alcohol use, and use of snuff or chewing tobacco. RESULTS: Current cigar smoking at baseline, as compared with never smoking, was associated with an increased risk of death from cancers of the lung (RR = 5.1; 95% confidence interval [CI] = 4.0-6.6), oral cavity/pharynx (RR = 4.0 [95% CI = 1.5-10.3]), larynx (RR = 10.3 [95% CI = 2.6-41.0]), and esophagus (RR = 1.8; 95% CI = 0.9-3.7). Although current cigar smokers overall did not appear to be at an increased risk of death from cancer of the pancreas (RR = 1.3; 95% CI = 0.9-1.9) or bladder (RR = 1.0; 95% CI = 0.4-2.3), there was an increased risk for current cigar smokers who reported that they inhaled the smoke (for pancreas, RR = 2.7; 95% CI = 1.5-4.8; for bladder, RR = 3.6; 95% CI = 1.3-9.9). CONCLUSIONS: Results from this large prospective study support a strong association between cigar smoking and mortality from several types of cancer.     

Cigarette smoking and risk of prostate cancer in the physicians' health study (United States)

To assess whether cigarette smoking is associated with prostate cancer incidence or mortality, we analyzed a large cohort of 22,071 men, aged 40-84 at baseline, in the Physicians' Health Study. During an average of 12.5 years of follow-up, we documented 996 cases of prostate cancer, including 113 fatal cases. Men were categorized according to smoking status, total pack-years smoked, and duration of smoking. We used Cox proportional hazard models to estimate the relative risks associated with smoking. Compared to never smokers, the age-adjusted relative risks (RR) of total prostate cancer were 1. 14 (95% confidence interval [CI] = 1.00-1.30) for past smokers, 1.10 (95% CI = 0.78-1.55) for current smokers of less than 20 cigarettes per day, and 1.10 (95% CI = 0.84-1.44) for current smokers of 20 or more cigarettes per day. Adjustment for body mass index, height, alcohol intake, and physical activity did not materially alter these findings. No significant association was observed in analyses of total pack-years smoked or duration of smoking. The results were similar for non-fatal and fatal prostate cancer. These data indicate no material association between cigarette smoking and prostate cancer incidence or mortality.     

Smoking and infectious agents and risk of in situ cervical cancer in Sydney, Australia

In a study of 116 in situ cervical cancer patients and 193 matched community controls in Sydney, Australia, smoking was found to be a major risk factor. Current smokers had a adjusted relative risk [RR] of 4.5 compared to nonsmokers [95% confidence interval (CI) 2.2-9.1] and exsmokers a RR of 1.3 [95% CI 0.6-3.0]. There was a stepwise dose-response relationship between risk and number of cigarettes smoked (30+ cigarettes/day, RR = 5.1, 95% CI 1.5-17.3); this dose-response relationship was more marked among current smokers. Years of cigarette smoking was not consistently related to risk. Exposures to herpes simplex virus type 2 and cytomegalovirus as measured by antibody prevalence were unrelated to risk (RR = 1.1 for both measures). However, cases appeared to have more exposure than controls to herpes simplex virus type 1 (RR = 2.3, 95% CI 1.1-4.4).     

Cigarette smoking, alcohol drinking and the risk of gallbladder cancer death: a prospective cohort study in Japan

Gallbladder cancer is a rare cancer with a poor prognosis, and few risk factors have been identified to date. This prospective study was conducted to evaluate the association of cigarette smoking and alcohol consumption with the risk of gallbladder cancer death. A baseline survey in 45 areas throughout Japan was conducted from 1988 to 1990 using a self-administered questionnaire, and a total of 113,496 participants (65,740 women) aged 40-89 years at entry were followed for 15 years. During the follow-up period, 165 gallbladder cancer deaths (95 women) were observed. Among women, the hazard ratio (HR) [95 percent confidence interval: 95% CI] of current smoker was 2.00 [0.91-4.42], when adjusted for age and drinking. There was no clear association between alcohol consumption and the risk. Among men, HR of current smoker was 2.27 [1.05-4.90]. HRs of those who smoked 21 cigarettes or more per day and those with 801-1,000 cigarette-years were 3.18 [1.18-8.53] and 3.44 [1.40-8.45], respectively, and positive linear associations were observed between that risk and the number of cigarettes per day (p for trend = 0.007) or "cigarette-years" (p for trend = 0.012). The alcohol dose was linearly associated with risk (p for trend = 0.004), where the HR among those who consumed 72.0 g or more of alcohol per day was 3.60 [1.29-9.85]. Among both men and women, cigarette smoking may elevate the risk of death from gallbladder cancer. Drinking may pose an elevated risk among men, but that seems to be less true among women.     

Cigarette smoking and the risk of gastric cancer: a pooled analysis of two prospective studies in Japan

To examine the association between cigarette smoking and the risk of gastric cancer, we conducted a pooled analysis of 2 population-based prospective cohort studies in rural northern Japan. Cohort 1 included 9,980 men (>or=40 years old) and Cohort 2 included 19,412 men (40-64 years old). The subjects completed a self-administered questionnaire on cigarette smoking and other health habits. We identified 228 cases of gastric cancer among Cohort 1 subjects (9 years of follow-up with 74,073 person-years) and 223 among Cohort 2 subjects (7 years of follow-up with 141,675 person-years). From each cohort, we computed the relative risk (RR) and 95% confidence interval (CI) of gastric cancer associated with smoking using a Cox regression analysis and pooled these estimates to obtain summary measures. The pooled multivariate RRs (95% CIs) for current smokers and past smokers compared to subjects who had never smoked were 1.84 (1.39-2.43) and 1.77 (1.29-2.43), respectively. The higher number of cigarettes smoked per day among current smokers was associated with a linear increase in risk (trend p < 0.05). The significant increase in risk for past smokers remained for up to 14 years after cessation. An increased risk was noted for cancer of the antrum but not for cardia or body lesions. The risk was increased for both differentiated and nondifferentiated histologic subtypes. Our findings support the hypothesis that cigarette smoking is a risk factor for gastric cancer.     

The Copenhagen case-control study of renal pelvis and ureter cancer: role of smoking and occupational exposures

Smoking habits and occupational exposures were investigated for 96 patients with cancer of the renal pelvis and ureter (including papilloma) and 294 hospital controls. In comparison with persons who never smoked, significantly increased relative risks were seen for smokers of cigarettes alone (RR = 2.6; 95% CI: 1.0-6.7) and in combination with other types of tobacco (RR = 3.8; 95% CI: 1.3-11.5). Non-significantly increased relative risks were observed for pipe smokers (RR = 2.2; 95% CI: 0.1-97) and for mixed pipe, cigar, and cigarillo smokers (RR = 6.5; 95% CI: 0.4-21.2). A strong dose-effect (p less than 0.001) relationship was seen between the lifetime total amount of tobacco smoked and the risk of pelvis-ureter tumors, with the heaviest smokers having an 8-fold risk. Comparison with the dose-effect relationship for a parallel study of bladder cancer indicated that the relationship with tobacco was stronger for pelvis-ureter tumors. Deep inhalation of cigarette smoke increased the risk (RR = 3.4; 95% CI: 1.9-6.1), while stopping smoking (RR = 0.6; 95% CI: 0.3-1.1) and use of filter cigarettes (RR = 0.5; 95% CI: 0.3-0.9) decreased the risk. Significantly increased risks emerged for employment in the chemical, petrochemical and plastics industries (RR = 4.0; 95% CI: 1.6-9.8), and for exposure to coal and coke (RR = 4.0; 95% CI: 1.2-13.6), asphalt and tar (RR = 5.5; 95% CI: 1.6-19.6). Cigarette smoking accounted for 56% of male and 40% of female pelvis and ureter tumors in eastern Denmark.     

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.     

Cigarette smoking and survival after ovarian cancer diagnosis.

We have examined the association between cigarette smoking and ovarian cancer survival in 676 women with invasive epithelial ovarian cancer, recruited into a case-control study in the early 1990s. Information about cigarette smoking and other personal and reproductive factors was obtained from a personal interview at the time of diagnosis. Cox proportional hazards models were used to evaluate the association between cigarette smoking and time to ovarian cancer death. Current smokers at diagnosis were more likely to die early than women who had never smoked [adjusted hazard ratio (HR), 1.36; 95% confidence interval (95% CI), 1.01-1.84]. Increased risks of dying were greater among those who had accumulated more pack-years of smoking (HR for 30+ pack-years compared with never smokers, 1.94; 95% CI, 1.41-2.66) and smoked more cigarettes per day (HR, 1.93; 95% CI, 1.37-2.73). All these associations were stronger among women with late-stage disease (HR for current versus never smokers, 1.58; 95% CI, 1.15-2.18). Time since quitting had little effect on survival after adjusting for lifetime smoking exposure. These results validate and extend recent findings and suggest that premorbid cigarette smoking is related to worse outcome in ovarian cancer patients.     

Smoking and mortality from esophageal cancer in China: a large case-control study of 19,734 male esophageal cancer deaths and 104,846 living spouse controls

An innovative population-based case-control study was conducted in a national mortality survey to assess the hazards of tobacco use on esophageal cancer among Chinese men. Cases were 19,734 males aged 35 years or older, who died of esophageal cancer during 1986-1988. Controls were 104,846 male living spouses of the same age when their wife died (of any cause) during the same period in the same county or city. The absolute esophageal cancer death rates were higher in smokers than those in nonsmokers in all geographical groups. The relative risks for esophageal cancer were 1.88 (95% CI: 1.73-2.05) and 1.39 (95% CI: 1.28-1.50) in urban and rural men, respectively, after adjustment for other relevant covariates including age group (5 years) and locality. When the calculation was restricted to men aged 35-69, the risk ratios for current cigarette smokers increased significantly with increasing number of cigarettes smoked daily and duration of smoking. Tobacco use, in any form, is an important risk factor for esophageal cancer in Chinese men. Selecting living spouses as controls is a unique and useful approach in the design of case-control studies of cigarette smoking.     

Passive smoking exposure and female breast cancer mortality

BACKGROUND: Several studies have reported positive associations between environmental tobacco smoke (ETS) and increased risk of breast cancer. However, studies of active smoking and risk of breast cancer are equivocal and in general do not support a positive association. To try to resolve this paradox, we examined the association between breast cancer mortality and potential ETS exposure from spousal smoking in an American Cancer Society prospective study of U.S. adult women. METHODS: We assessed breast cancer death rates in a cohort of 146 488 never-smoking, single-marriage women who were cancer free at enrollment in 1982. Breast cancer death rates among women whose husbands smoked were compared with those among women married to men who had never smoked. Cox proportional hazards modeling was used to control for potential risk factors other than ETS exposure. RESULTS: After 12 years of follow-up, 669 cases of fatal breast cancer were observed in the cohort. Overall, we saw no association between exposure to ETS and death from breast cancer (rate ratio [RR] = 1.0; 95% confidence interval [CI] = 0.8-1.2). We did, however, find a small, not statistically significant increased risk of breast cancer mortality among women who were married before age 20 years to smokers (RR = 1. 2; 95% CI = 0.8-1.8). CONCLUSIONS: In contrast to the results of previous studies, this study found no association between exposure to ETS and female breast cancer mortality. The results of our study are particularly compelling because of its prospective design as compared with most earlier studies, the relatively large number of exposed women with breast cancer deaths, and the reporting of exposure by the spouse rather than by proxy.     

Overall obesity, abdominal adiposity, diabetes and cigarette smoking in relation to the risk of pancreatic cancer in two Swedish population-based cohorts

We examined the associations of body mass index (BMI), waist circumference, a history of diabetes, and cigarette smoking with risk of pancreatic cancer among 37,147 women and 45,906 men followed up during 560,666 person-years in the Swedish Mammography Cohort and the Cohort of Swedish Men; 136 incident cases of pancreatic cancer were diagnosed. The multivariate rate ratio (RR) of pancreatic cancer for obese women and men (BMI > or =30 kg/m(2)) was 1.81 (95% CI: 1.04-3.15) compared to those with a BMI of 20-25 kg/m(2). For a difference of 20 cm (about two standard deviations) in waist circumference, the multivariate RRs were 1.32 (95% CI: 0.73-2.37) among women and 1.74 (95% CI: 1.00-3.01) among men. Pancreatic cancer risk was associated with history of diabetes (multivariate RR: 1.88; 95% CI: 1.09-3.26) and cigarette smoking (multivariate RR for current compared with never smokers: 3.06; 95% CI: 1.99-4.72). Current smokers of > or =40 pack-years had a five-fold elevated risk compared with never smokers. Risk among past smokers approached the RR for never smokers within 5-10 years following smoking cessation. Findings from this prospective study support positive relationships of overall obesity, abdominal adiposity, diabetes and smoking with risk of pancreatic cancer.     

A prospective study of stomach cancer among a rural Japanese population: a 6-year survey.

Stomach cancer mortality was prospectively studied among 9753 Japanese men and women who first responded to a mailed questionnaire in 1985 and were then followed through May 31, 1991. During this follow-up period, 57 stomach cancer deaths were identified. Current smokers had an increased risk of deaths from stomach cancer compared with never smokers (relative risk (RR) = 2.29, 95% confidence interval (CI): 1.15-4.56), but there was no dose-response to amount of cigarettes smoked. Daily alcohol drinkers who consumed 50 ml or more of alcohol per day also had a greater risk than nondrinkers (RR = 3.05, 95% CI: 1.35-6.91). There was no association between stomach cancer mortality and individual food consumption except a positive association with fruit intake. However, frequent use (greater than or equal to 3-4/week) of broiling of meats and traditional style Japanese salad preparation in their cooking procedures were positively associated with stomach cancer mortality. The RR values compared with infrequent use (less than or equal to 1-2/month) were 2.27 (95% CI: 1.06-4.85) and 3.10 (95% CI: 1.40-6.85), respectively. A positive family history of cancer, especially stomach cancer, significantly increased the risk of stomach cancer deaths (RR = 2.01, 95% CI: 1.12-3.63). The effects of these variables remained after adjustment for other variables.     

Differences between small-cell lung cancer and non-small-cell lung cancer among tobacco smokers

It is known that smoking increases the risk for all histological subtypes of lung cancer. To date, the factors that determine why some patients develop small-cell lung cancer (SCLC) while others develop non-small-cell lung cancer (NSCLC) remain unknown. We compared the characteristics of 774 smokers with SCLC and NSCLC diagnosed during the period January 1999 till December 2002. Multivariate logistic regression was used to estimate the odds ratio (OR) with 95% CI. Testing of linear trend across categories of pack-years was also conducted. Six hundred and sixty-five NSCLC were compared to 109 SCLC. Among SCLC, there were significantly more females (20.2% versus 12.8%), current-smokers (81.7% versus 71.9%) as well as smokers who had smoked more than 40 pack-years (75.6% versus 50.3%). Comparing SCLC with NSCLC among the men only, having smoked more than 40 pack-years was associated with a significantly elevated odds ratio (OR) of 3.71 of developing SCLC (95% CI, 1.05-13.1; p=0.041). There was a decreasing trend in OR with increasing smoking cessation period. When comparing SCLC with adenocarcinoma, the women had a higher OR of 2.37 of developing SCLC (95% CI, 1.05-5.31; p=0.037) compared to the men. Our findings suggest that cumulative smoking exposure in terms of pack-years smoked is an important determining factor for the preferred development of SCLC among smokers.