Risk of lung cancer and consumption of vegetables and fruit in Japanese: A pooled analysis of cohort studies in Japan

International reviews have concluded that consumption of fruit and vegetables might decrease the risk of lung cancer. However, the relevant epidemiological evidence still remains insufficient in Japan. Therefore, we performed a pooled analysis of data from four population‐based cohort studies in Japan with >200 000 participants and >1700 lung cancer cases. We computed study‐specific hazard ratios by quintiles of vegetable and fruit consumption as assessed by food frequency questionnaires. Summary hazard ratios were estimated by pooling the study‐specific hazard ratios with a fixed‐effect model. In men, we found inverse associations between fruit consumption and the age‐adjusted and area‐adjusted risk of mortality or incidence of lung cancer. However, the associations were largely attenuated after adjustment for smoking and energy intake. The significant decrease in risk among men remained only for a moderate level of fruit consumption; the lowest summary hazard ratios were found in the third quintile of intake (mortality: 0.71, 95% confidence interval 0.60–0.84; incidence: 0.83, 95% confidence interval 0.70–0.98). This decrease in risk was mainly detected in ever smokers. Conversely, vegetable intake was positively correlated with the risk of incidence of lung cancer after adjustment for smoking and energy intake in men (trend P, 0.024); the summary hazard ratio for the highest quintile was 1.26 (95% confidence interval 1.05–1.50). However, a similar association was not detected for mortality from lung cancer. In conclusion, a moderate level of fruit consumption is associated with a decreased risk of lung cancer in men among the Japanese population.     

Cigarette smoking,alcohol consumption and subsequent gastric cancer risk by subsite and histologic type

The effect of cigarette smoking or alcohol consumption on the risk of gastric cancer has not been clarified. We investigated this relationship, considering the anatomic subsite and histologic type of gastric cancer. A total of 19,657 men (aged 40-59 years at baseline), who responded to the baseline questionnaire and reported no serious illness at that time, were followed for 10 years, from January 1990 to December 1999. Gastric cancer was confirmed histologically in 293 men. Smoking was associated with an increased risk of the differentiated type of distal gastric cancer; compared to the group who never smoked, the adjusted rate ratios (RRs) of gastric cancer for past and current smokers were 2.0 (95% CI 1.1-3.7) and 2.1 (95% CI 1.2-3.6), respectively. No association was observed between cigarette smoking and risk of the undifferentiated type of distal gastric cancer except for a suggestive association with cardia cancer. For alcohol consumption, elevated risk was suggested only for cardia cancer of all histologic types, though the relationship failed to reach significance. Among those who drank alcohol at least once per week, RRs for ethanol intake of 2.7-161.0, 162.0-322.0 and 322.5+ g/week compared to those who drank 0-3 times/month were 2.5 (95% CI 0.7-9.5), 3.3 (0.9-11.6) and 3.0 (0.8-11.1), respectively (p(trend) = 0.66). In conclusion, our results confirm that smoking is related to gastric cancer of the differentiated type. Further studies with more cases are needed to detect a positive association between cigarette smoking or alcohol consumption and cardia 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.     

Fruits, vegetables and lung cancer: a pooled analysis of cohort studies

Inverse associations between fruit and vegetable consumption and lung cancer risk have been consistently reported. However, identifying the specific fruits and vegetables associated with lung cancer is difficult because the food groups and foods evaluated have varied across studies. We analyzed fruit and vegetable groups using standardized exposure and covariate definitions in 8 prospective studies. We combined study-specific relative risks (RRs) using a random effects model. In the pooled database, 3,206 incident lung cancer cases occurred among 430,281 women and men followed for up to 6-16 years across studies. Controlling for smoking habits and other lung cancer risk factors, a 16-23% reduction in lung cancer risk was observed for quintiles 2 through 5 vs. the lowest quintile of consumption for total fruits (RR = 0.77; 95% CI = 0.67-0.87 for quintile 5; p-value, test for trend < 0.001) and for total fruits and vegetables (RR = 0.79; 95% CI = 0.69-0.90; p-value, test for trend = 0.001). For the same comparison, the association was weaker for total vegetable consumption (RR = 0.88; 95% CI = 0.78-1.00; p-value, test for trend = 0.12). Associations were similar between never, past, and current smokers. These results suggest that elevated fruit and vegetable consumption is associated with a modest reduction in lung cancer risk, which is mostly attributable to fruit, not vegetable, intake. However, we cannot rule out the possibility that our results are due to residual confounding by smoking. The primary focus for reducing lung cancer incidence should continue to be smoking prevention and cessation.     

Fruit consumption reduces the effect of smoking on bladder cancer risk. The Belgian case control study on bladder cancer

We have hypothesized that consumption of fruit and vegetables may be associated with reduced risk of bladder cancer and that this may interact with cigarette smoking and metabolic genetic polymorphisms. A population-based case-control study was performed in the Belgian province of Limburg among 200 cases and 385 controls. Logistic regression was performed to calculate odds ratios (ORs) for bladder cancer occurrence with corresponding 95% confidence intervals (95% CI). Effect modification by smoking was investigated. We also evaluated interaction between fruit intake and GSTM1, GSTT1, NAT2 and SULT1A1 amongst "ever-smokers." Total vegetable intake was not significantly associated with the risk of bladder cancer (OR 1.15, 95% CI: 0.70-1.88 for the highest compared to the lowest tertile). However, total fruit intake was negatively associated with bladder cancer risk (OR 0.61, 95% CI 0.37-0.99 comparing the same tertiles). Among individuals with low daily fruit consumption, ever smokers had a highly increased risk of bladder cancer risk (OR: 4.23, 95% CI: 1.91-9.40). By increasing the daily fruit consumption, the risk of "ever-smokers" for developing bladder cancer decreased, however it remained significant (OR: 2.15; 95CI%: 1.15-4.05). No interaction was identified between the different genotypes and fruit consumption. We conclude that fruit consumption may decrease the effect of smoking on developing bladder cancer. Antioxidants, found in fruit, may protect against the damage caused by free radicals found in cigarette smoke. Metabolic polymorphisms appear not to modify this relation.     

Association between alcohol and lung cancer in the alpha-tocopherol, beta-carotene cancer prevention study in Finland

Objectives: We evaluated the association between alcohol intake and lung cancer in a trial-based cohort in Finland, the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study (ATBC Study).Methods: During an average of 7.7 years of follow-up, 1059 lung cancer cases were diagnosed among the 27,111 male smokers with complete alcohol and dietary information. The relationship between alcohol and lung cancer was assessed in multivariate Cox regression models that adjusted for age, smoking, body mass index and intervention group.Results: Nondrinkers, 11% of the study population, were at increased lung cancer risk compared to drinkers (RR = 1.2, 95% CI: 1.0–1.4), possibly due to the inclusion of ex-drinkers who had stopped drinking for health reasons. Among drinkers only, we observed no association between lung cancer and total ethanol or specific beverage (beer, wine, spirits) intake. We found no significant effect modification by level of smoking, dietary micronutrients or trial intervention group; however, for men in the highest quartile of alcohol intake, we observed a slight increase in risk for lighter smokers (>1 pack/day) and reduced risk among the heaviest smokers (<30 cigarettes/day).Conclusions: We concluded that alcohol consumption was not a risk factor for lung cancer among male cigarette smokers, and its effect was not significantly modified by other factors, notably smoking history.     

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.     

Vegetables and fruits consumption and risk of esophageal and gastric cancer subtypes in the Netherlands Cohort Study

Prospective epidemiologic data on vegetables and fruits consumption and risk of subtypes of esophageal and gastric cancer are sparse. We studied the association between vegetables and fruits consumption and risk of esophageal squamous cell carcinoma (ESCC), esophageal adenocarcinoma (EAC), gastric cardia adenocarcinoma (GCA) and gastric noncardia adenocarcinoma (GNCA) in the Netherlands Cohort Study. In 1986, 120,852 Dutch men and women aged 55-69 filled out a questionnaire on diet and other cancer risk factors. After 16.3 years of follow-up, 101 ESCC, 144 EAC, 156 GCA, 460 GNCA cases and 4,035 subcohort members were available for case-cohort analysis using Cox proportional hazards models. Multivariable adjusted incidence rate ratios (RRs) were generally below unity. Total vegetable consumption was nonsignificantly inversely associated with EAC and ESCC risk, but not with GCA and GNCA risk. Significant inverse associations were observed for raw vegetables and EAC risk [RR per 25 g/day: 0.81, 95% confidence interval (CI) 0.68-0.98], and Brassica vegetables and GCA risk (RR per 25 g/day: 0.72, 95% CI 0.54-0.95). Total fruit consumption was associated with a nonsignificantly decreased EAC risk. Citrus fruits were inversely associated with EAC and GCA risk (RRs for highest vs. lowest intake: 0.55, 95% CI 0.31-0.98 and 0.38, 95% CI 0.21-0.69, respectively). Specifically for current smokers, vegetables and possibly also fruits intake was inversely associated with ESCC and EAC risk. Consumption of (specific groups of) vegetables and fruits may protect against subtypes of esophageal and gastric cancer.     

Physical activity and lung cancer risk in male smokers

We examined the association between physical activity and lung cancer in a prospective cohort of 27,087 male smokers, ages 50-69 years, enrolled in the Alpha-Tocopherol, Beta Carotene Cancer Prevention (ATBC) Study. After an average of 10 years of follow-up, 1,442 lung cancer cases were diagnosed. Cox proportional hazards models were used to estimate the relative risk (RR) and 95% confidence intervals (CI) of lung cancer associated with self-reported occupational and leisure-time activity, adjusted for age, supplement group, body mass index, cigarettes smoked daily, years of smoking, education, energy intake and vegetable intake. There were no associations between occupational, leisure-time or combined categories of physical activity with lung cancer risk; however, age appeared to modify the effect of leisure-time activity (p = 0.02). Within increasing quartiles of age, the RRs (CI) for men active in leisure time compared to sedentary men were 0.77 (0.54-1.09), 0.74 (0.57-0.95), 1.09 (0.89-1.33) and 1.03 (0.88-1.21). These data suggest that among smokers, neither occupational nor leisure-time activity is associated with lung cancer risk. There may, however, be some modest risk reduction associated with leisure activity among younger smokers. Published 2002 Wiley-Liss, Inc.     

Alcohol consumption, smoking, and subsequent risk of colorectal cancer in middle-aged and elderly Japanese men and women: Japan Public Health Center-based prospective study.

Few studies have examined the association of alcohol consumption and cigarette smoking with colorectal cancer in Asian populations whose genetic susceptibility to these factors are different from Western populations. We investigated this association and the joint effect of these factors, and estimated the population-attributable fraction to clarify the public health impact on a Japanese population, based on a prospective study. We analyzed the 10-year (cohort I) and 7-year (cohort II) follow-up data of the Japan Public Health Center-based prospective study on cancer and cardiovascular disease, derived from 90,004 (42,540 male and 47,464 female) middle-aged and elderly Japanese. We identified 716 (457 in men and 259 in women) newly diagnosed cases of colorectal cancer. Both alcohol consumption and smoking were clearly associated with colorectal cancer in men, after adjusting for age, family history of colorectal cancer, body mass index, and physical exercise. Regular heavy drinking of 150 g/week or more of ethanol showed a statistically significant increased risk compared with nondrinkers: relative risks (RRs) were 1.4 [95% confidence interval (CI), 1.1-1.9] for 150-299 g/week and 2.1 (95% CI, 1.6-2.7) for 300 g/week or more. On the contrary, regular ethanol consumption was not associated with colorectal cancer (RR, 0.7; 95% CI, 0.4-1.1) in women. In terms of smoking, the RRs were 1.4 (95% CI, 1.1-1.8) for current smokers and 1.3 (95% CI, 0.98-1.7) for ex-smokers compared with never-smokers in men. The risk of smoking in women was similar to that in men, although not statistically significant. The colorectal cancer risk with 300 g/week or more of ethanol in current smokers was estimated at 3.0 (95% CI, 1.8-5.1) compared with nondrinkers among nonsmokers in men. Colorectal cancer attributable to alcohol consumption or smoking was estimated to be 46%. In conclusion, approximately half of the colorectal cancer cases may be preventable by tobacco and alcohol controls in middle-aged and elderly Japanese men.     

Lung cancer risk comparison among male smokers between the "six-prefecture cohort" in Japan and the British physicians' cohort

We estimated the effective duration of cigarette smoking using the data of lung cancer mortality among male smokers of a large-scale cohort study in Japan and evaluated its role in the lung cancer risk difference between male smokers of the Japanese cohort and the British physicians' cohort. By selecting male cohort members who answered that they had started smoking at ages 18-22 (average = 20.3), the subjects of our analysis, which numbered 49,013, were made relatively homogeneous in terms of age at which smoking was started. Assuming lung cancer mortality to be proportional to the 4.5th power of the effective duration of cigarette smoking, i.e., (age-theta)4.5, as was proposed on the basis of the British cohort study by Doll and Peto, the parameter theta was estimated to be 29.4 for male smokers aged 40-64 in 1966; therefore, the estimated duration of cigarette smoking was, on average, 9.1 years (95% confidence interval = 5.8-11.6) shorter than that calculated from the reported age at which smoking was started. Our findings suggested that the low lung cancer mortality relative to daily cigarette consumption in Japan resulted from the shorter duration of cigarette smoking in the Japanese cohort, possibly due to the severe shortage of cigarettes during and shortly after World War II. Once the effective duration of cigarette smoking was adjusted, lung cancer mortality in the range of 5-34 cigarettes per day was fairly comparable to that observed among the cohort of male British physicians.     

Diet, reproductive factors and lung cancer risk among Chinese women in Singapore: evidence for a protective effect of soy in nonsmokers.

The factors associated with risk of lung cancer among nonsmokers have not been fully elucidated, but dietary factors have consistently been shown to play a role. Chinese women are unique in having a high incidence of lung cancer despite a low smoking prevalence. This population is also known to have a high intake of soy, a dietary source of phytoestrogens. We conducted a hospital-based case-control study among Singapore Chinese women, comprising 303 cases and 765 age-matched controls, of whom 176 cases and 663 controls were lifetime nonsmokers. Data on demographic background, reproductive factors and dietary intake of fruit, vegetables and soy foods were obtained by in-person interview. We observed an inverse association between intake of total, cruciferous and non-cruciferous vegetables and risk of lung cancer among smokers. Although smokers in the highest tertile of fruit intake also had a lower risk, this was not statistically significant. Higher intake of soy foods significantly reduced risk of lung cancer among lifetime nonsmokers, but not among smokers. When soy isoflavonoid intake in mg/week was computed based on frequency and portion size of intake of eight common local soy foods, the adjusted OR among nonsmokers for the highest tertile compared to the lowest was 0.56, 95% CI 0.37-0.85 (p for trend <0.01). Fruit intake was also significantly associated with reduced lung cancer risk among nonsmokers, but the effect was not significant after adjustment for soy intake. On the other hand, soy intake remained an independent predictor of risk after controlling for fruit intake. Reproductive effects were also primarily confined to lifetime nonsmokers, among whom having 3 or more livebirths (adjusted OR 0.65, 0.44-0.96) and a menstrual cycle length of more than 30 days (OR 0.46, 0.25-0.84) accorded a significantly reduced risk of lung cancer. Place of birth was significantly associated with risk among nonsmokers (OR 2.6, 1.7-3.9 for China-born vs. local born) but not among smokers. When analysis was restricted to nonsmokers with adenocarcinomas, the dietary effects were consistent or enhanced. On stepwise regression, soy intake and cycle length emerged as the independent dietary and reproductive predictors of lung cancer risk in nonsmokers. These findings are consistent with other evidence suggesting an involvement of estrogen-related pathways in lung cancer among non-smoking women.     

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.     

Fatty foods and the risk of lung cancer: A case-control study from Uruguay

To examine whether fatty-food consumption modifies lung-cancer risk, a case-control study involving 377 patients with lung cancer and 377 controls was conducted in Uruguay. The study was restricted to men. Dietary patterns were assessed in detail using a 64-item food-frequency questionnaire, which allowed the calculation of total energy intake. After adjustment for potential confounders (body-mass index, family history of lung cancer, total energy intake and tobacco smoking), an increase in risk for fatty-food consumption was observed. In particular, fried foods (OR, 1.54; 95% CI, 1.01-2.35), dairy products (OR, 2.85; 95% CI, 1.73-4.69) and desserts (OR, 2.52; 95% CI, 1.54-4.12) were associated with increases in lung-cancer risk and significant dose-response patterns. The association with dairy products was more evident for adenocarcinoma of the lung (OR, 4.18; 95% CI, 1.87-9.36), whereas increased risks for fried-meat and dessert consumption were observed in each cell type. The association with fried-meat consumption was more pronounced for current smokers and for heavy smokers, whereas dairy products and desserts were associated with risk both in current and in past smokers. In conclusion, fat-rich foods and sucrose-rich foods were positively associated with an increased risk of lung cancer. Although the relationship between fat consumption and lung cancer has been reported, the direct association of lung cancer with sucrose-rich foods should be further investigated. Int. J. Cancer 71: 760-766, 1997. © 1997 Wiley-Liss Inc.     

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.     

Cigarette smoking, alcohol consumption, and breast cancer risk

The effects of cigarette smoking and alcohol consumption on breast cancer risk were investigated in 276 primary, histologically confirmed breast cancer patients and 1,519 community-based comparison subjects identified in 1977 and 1978 in North Carolina. Data on both behaviors and other pertinent personal and medical characteristics were obtained by interview. Analytic methods included stratification and logistic regression. Among current cigarette smokers of 1-20 cigarettes per day and over 20 per day, the odds ratios (ORs) adjusted for age, race, alcohol consumption, estrogen use, and oral contraceptive use for breast cancer were 0.75 [95% confidence interval (CI) 0.52-1.09] and 0.57 (95% CI 0.30-1.08), respectively. A decrease in risk was not seen in former smokers. With respect to alcohol consumption, the adjusted OR for those having one drink or more per week compared to those having less than one was 1.45 (95% CI 0.99-2.12). If the comparison was ever versus never drinkers, the adjusted OR was 1.47 (95% CI 1.10-1.97); for current drinkers versus nondrinkers, the adjusted OR was 1.89 (95% CI 1.40-2.56). The ORs were adjusted for age, race, cigarette smoking, estrogen use, an oral contraceptive use. These data supports those reports showing an inverse association of cigarette smoking and a positive association of alcohol consumption with breast cancer risk.     

Cigarette smoking, alcohol intake, and thyroid cancer risk: a pooled analysis of five prospective studies in the United States

Objective

We examined the associations between cigarette smoking, alcohol intake, and thyroid cancer risk in a pooled analysis of five prospective studies.

Methods

Data from five prospective U.S. studies were standardized and then combined into one aggregate dataset (384,433 men and 361,664 women). Pooled hazard ratios (HR) and 95?% confidence intervals (CI) for thyroid cancer were estimated from mutually adjusted models of cigarette smoking and alcohol intake, which were additionally adjusted for age, sex, education, race, marital status, body mass index, and cohort.

Results

Over follow-up, 1,003 incident thyroid cancer cases (335 men and 668 women) were identified. Compared to never smokers, current smoking was associated with reduced risk of thyroid cancer (HR?=?0.68, 95?% CI 0.55–0.85); this association was slightly stronger among non-drinkers (HR?=?0.46, 95?% CI 0.29–0.74). No reduction in risk was observed for former, compared to never, smokers. Greater smoking intensity, duration, and pack-years were associated with further reductions in risk among former and current smokers. Alcohol intake was also inversely associated with thyroid cancer risk (≥7 drinks/week versus 0, HR?=?0.72, 95?% CI 0.58–0.90, p trend?=?0.002). Inverse associations with smoking and alcohol were more pronounced for papillary versus follicular tumors.

Conclusion

The results of this pooled analysis suggest that both cigarette smoking and alcohol consumption are associated with reduced risks of papillary thyroid cancer and, possibly, follicular thyroid cancer.     

Fruits and vegetables and lung cancer: Findings from the European Prospective Investigation into Cancer and Nutrition

Intake of fruits and vegetables is thought to protect against the development of lung cancer. However, some recent cohort and case-control studies have shown no protective effect. We have assessed the relation between fruit and vegetable intake and lung cancer incidence in the large prospective investigation on diet and cancer, the European Prospective Investigation Into Cancer and Nutrition (EPIC). We studied data from 478,021 individuals that took part in the EPIC study, who were recruited from 10 European countries and who completed a dietary questionnaire during 1992-1998. Follow-up was to December 1998 or 1999, but for some centres with active follow-up to June 2002. During follow-up, 1,074 participants were reported to have developed lung cancer, of whom 860 were eligible for our analysis. We used the Cox proportional hazard model to determine the effect of fruit and vegetable intake on the incidence of lung cancer. We paid particular attention to adjustment for smoking. Relative risk estimates were obtained using fruit and vegetable intake categorised by sex-specific, cohort-wide quintiles. After adjustment for age, smoking, height, weight and gender, there was a significant inverse association between fruit consumption and lung cancer risk: the hazard ratio for the highest quintile of consumption relative to the lowest being 0.60 (95% Confidence Interval 0.46-0.78), p for trend 0.0099. The association was strongest in the Northern Europe centres, and among current smokers at baseline, and was strengthened when the 293 lung cancers diagnosed in the first 2 years of follow-up were excluded from the analysis. There was no association between vegetable consumption or vegetable subtypes and lung cancer risk. The findings from this analysis can be regarded as re-enforcing recommendations with regard to enhanced fruit consumption for populations. However, the effect is likely to be small compared to smoking cessation.     

饮酒与膀胱癌关系的全人群病例对照研究

目的探讨饮酒与膀胱癌发生的关系。方法采用全人群为基础的病例对照研究,共调查1996年1月1日~1998年12月31日期间确诊的上海市区膀胱癌新发病例608例,健康人群对照607例。采用非条件logistic回归分析,调整吸烟等可能的混杂因素,以估计饮酒对膀胱癌发生的危险度及其95%可信区间。结果与不饮酒者相比,男、女性饮酒者患膀胱癌相对危险度分别是1.22(95%CI0.94~1.59)、0.50(95%CI0.13~1.90)。男性随总酒精摄入量增加患膀胱癌的危险有增加趋势,OR值分别为1.10(1~80g/d)和1.56(>80g/d)(趋势检验P=0.043)。男性总酒精摄入量与饮酒年限的联合作用分析表明,与不饮酒者相比,总酒精摄入量超过80g/d、饮酒年限超过40年者患膀胱癌危险度为2.11(95%CI1.11~4.01)。将饮酒分3层、吸烟分4层进行男性饮酒与吸烟的联合作用分析,结果显示总酒精摄入量>80g/d且吸烟≥35包年者的OR值为2.78(95%CI1.46~5.28)。未发现各饮酒种类与男性膀胱癌有显著关联。在不吸烟男性组中的分析显示,饮酒习惯的OR值均没有统计学意义。结论饮酒可能与男性膀胱癌有一定联系,但作用较弱,似乎主要表现为对吸烟男性的作用。     

Lung Cancer Risk Comparison among Male Smokers between the "Six-prefecture Cohort" in Japan and the British Physicians' Cohort

We estimated the effective duration of cigarette smoking using the data of lung cancer mortality among male smokers of a large-scale cohort study in Japan and evaluated its role in the lung cancer risk difference between male smokers of the Japanese cohort and the British physicians' cohort. By selecting male cohort members who answered that they had started smoking at ages 18–22 (average = 20.3), the subjects of our analysis, which numbered 49,013, were made relatively homogeneous in terms of age at which smoking was started. Assuming lung cancer mortality to be proportional to the 4.5th power of the effective duration of cigarette smoking, i.e., (age—θ)^4,5, as was proposed on the basis of the British cohort study by Doll and Peto, the parameter θ was estimated to be 29.4 for male smokers aged 40–64 in 1966; therefore, the estimated duration of cigarette smoking was, on average, 9.1 years (95% confidence interval=5.8–11.6) shorter than that calculated from the reported age at which smoking was started. Our findings suggested that the low lung cancer mortality relative to daily cigarette consumption in Japan resulted from the shorter duration of cigarette smoking in the Japanese cohort, possibly due to the severe shortage of cigarettes during and shortly after World War II. Once the effective duration of cigarette smoking was adjusted, lung cancer mortality in the range of 5–34 cigarettes per day was fairly comparable to that observed among the cohort of male British physicians.