A prospective study of cruciferous vegetables and prostate cancer.

High intake of cruciferous vegetables may offer some protection against prostate cancer, but overall data are inconclusive. Thus, we examined the association between cruciferous vegetable intake and risk of prostate cancer in the Health Professionals Follow-Up Study. Between 1986 and 2000, 2,969 cases of nonstage T1a prostate cancer were diagnosed in 47,365 men who completed dietary assessments in 1986, 1990, and 1994. We calculated the multivariate relative risk (RR) and 95% confidence intervals (CIs) using Cox regression. Overall, we found no appreciable association between baseline intake of cruciferous vegetables and risk of prostate cancer (RR, 0.93; 95% CI, 0.82-1.05, for > or = 5 versus < or = 1 serving/week; P for trend = 0.30), and only a slight suggestive association for organ-confined prostate cancer (RR, 0.88; 95% CI, 0.74-1.05; P for trend = 0.06). The inverse association was stronger for men under the age of 65 years (RR, 0.81; 95% CI, 0.64-1.02; P for trend = 0.02), especially for organ-confined cancers (RR, 0.72; 95% CI, 0.54-0.97; P for trend = 0.007). In addition, this inverse association was stronger when we restricted the analysis to men with more consistent intake of vegetables over the 10 years before 1986, when we limited the analysis to men who had had a prostate-specific antigen test, and when we considered an 8-year time lag. This study does not provide compelling evidence of a protective influence of cruciferous vegetables on prostate cancer risk. However, if cruciferous vegetables are protective early in prostate carcinogenesis, as suggested by proposed mechanisms, we may expect stronger associations, as observed, for more remote diet for prostate-specific antigen-detected early stage (organ-confined) cancers in younger men. In contrast, for advanced cancers in older men, which were probably initiated decades in the past, recent dietary intakes of cruciferous vegetables may be irrelevant. These findings suggest that future studies of cruciferous vegetables should focus on early stages of prostate cancer.     

Interplay between dietary inducers of GST and the GSTM-1 genotype in colon cancer

The purpose of this study is to determine if cruciferous vegetables and coffee, two dietary inducers of glutatione-S-transferases, interact with GSTM-1 genotype to alter risk of colon cancer. Data were available on 1579 incident cases of adenocarcinoma of the colon and 1898 population-based controls. Intake of cruciferous vegetables, specific types of cruciferous vegetable, and coffee were not associated with colon cancer; GSTM-1 genotype did not modify these associations. However, age at diagnosis and cigarette smoking appeared to be important effect modifiers of the associations between GSTM-1, cruciferous vegetables and colon cancer. Among GSTM-1 null individuals, <55 years at diagnosis, we observed an inverse association between colon cancer and high levels of cruciferous vegetable intake relative to people who did not eat cruciferous vegetables (ORs 0.23 95% CI 0.10-0.54); broccoli was the cruciferous vegetable associated with the strongest inverse association (OR 0.30 95% CI 0.13-0.70). Among younger individuals who were GSTM-1 present (relative to those with GSTM-1 null), we observed an inverse association with colon cancer regardless of level of cruciferous vegetable intake (OR 0.74 95% CI 0.30-1.79 for no intake; OR 0.44 95% CI 0.21-0.92 for <4 servings/week; and OR 0. 44 95% CI 0.19-0.99 for >/=4 servings/week). These associations were further modified by cigarette smoking. People <65 years of age who smoked had a greater reduction in risk of colon cancer from consumption of cruciferous vegetables than non-smokers at the same age. In summary, although cruciferous vegetables do not appear to modify colon cancer risk in the total population, there are subgroups of the population for whom these vegetables may be important. These subgroups are defined mostly by age and smoking status.     

Vegetable and fruit intake after diagnosis and risk of prostate cancer progression

Cruciferous vegetables, tomato sauce and legumes have been associated with reduced risk of incident advanced prostate cancer. In vitro and animal studies suggest these foods may inhibit progression of prostate cancer, but there are limited data in men. Therefore, we prospectively examined whether intake of total vegetables, and specifically cruciferous vegetables, tomato sauce and legumes, after diagnosis reduce risk of prostate cancer progression among 1,560 men diagnosed with non-metastatic prostate cancer and participating in the Cancer of the Prostate Strategic Urologic Research Endeavor, a United States prostate cancer registry. As a secondary analysis, we also examined other vegetable subgroups, total fruit and subgroups of fruits. The participants were diagnosed primarily at community-based clinics and followed from 2004 to 2009. We assessed vegetable and fruit intake via a semi-quantitative food frequency questionnaire, and ascertained prostate cancer outcomes via urologist report and medical records. We observed 134 events of progression (53 biochemical recurrences, 71 secondary treatments likely due to recurrence, 6 bone metastases and 4 prostate cancer deaths) during 3,171 person-years. Men in the fourth quartile of post-diagnostic cruciferous vegetable intake had a statistically significant 59% decreased risk of prostate cancer progression compared to men in the lowest quartile (hazard ratio (HR): 0.41; 95% confidence interval (CI): 0.22, 0.76; p-trend: 0.003). No other vegetable or fruit group was statistically significantly associated with risk of prostate cancer progression. In conclusion, cruciferous vegetable intake after diagnosis may reduce risk of prostate cancer progression.     

Consumption of raw cruciferous vegetables is inversely associated with bladder cancer risk.

Cruciferous vegetables contain isothiocyanates, which show potent chemopreventive activity against bladder cancer in both in vitro and in vivo studies. However, previous epidemiologic studies investigating cruciferous vegetable intake and bladder cancer risk have been inconsistent. Cooking can substantially reduce or destroy isothiocyanates, and could account for study inconsistencies. In this hospital-based case-control study involving 275 individuals with incident, primary bladder cancer and 825 individuals without cancer, we examined the usual prediagnostic intake of raw and cooked cruciferous vegetables in relation to bladder cancer risk. Odds ratios (OR) and 95% confidence intervals (CI) were estimated with unconditional logistic regression, adjusting for smoking and other bladder cancer risk factors. We observed a strong and statistically significant inverse association between bladder cancer risk and raw cruciferous vegetable intake (adjusted OR for highest versus lowest category = 0.64; 95% CI, 0.42-0.97), with a significant trend (P = 0.003); there were no significant associations for fruit, total vegetables, or total cruciferous vegetables. The associations observed for total raw crucifers were also observed for individual raw crucifers. The inverse association remained significant among current and heavy smokers with three or more servings per month of raw cruciferous vegetables (adjusted ORs, 0.46 and 0.60; 95% CI, 0.23-0.93 and 0.38-0.93, respectively). These data suggest that cruciferous vegetables, when consumed raw, may reduce the risk of bladder cancer, an effect consistent with the role of dietary isothiocyanates as chemopreventive agents against bladder cancer.     

Intakes of fruits, vegetables, and related nutrients and the risk of non-Hodgkin's lymphoma among women.

Non-Hodgkin's lymphoma is etiologically related to suppressed immune status, and certain nutrients found in fruits and vegetables have been associated with increased immune responses. However, limited information exists on associations between intake of fruits, vegetables, and related nutrients and non-Hodgkin's lymphoma risk. We thus examined these associations among 88,410 women in the Nurses' Health Study cohort who were aged 34-60 years in 1980 and provided dietary information in 1980. During 14 years of follow-up, we documented 199 incident cases of non-Hodgkin's lymphoma. Higher intake of fruits and vegetables was associated with a lower risk of non-Hodgkin's lymphoma (P for trend = 0.02); the multivariate relative risk (RR) was 0.62 [95% confidence interval (CI), 0.38-1.02] for women who consumed greater than or equal to six servings per day as compared with those consuming less than three servings per day. When fruits and vegetables were examined separately, intake of vegetables rather than fruits was most clearly associated with a reduced risk (P for trend = 0.02 for vegetables; P for trend = 0.16 for fruits); compared with those consuming less than one serving per day, the multivariate RRs were 0.62 (95% CI, 0.35-1.07) for women who consumed greater than or equal to three servings per day of vegetables and 0.70 (95% CI, 0.44-1.12) for women who consumed this amount of fruits. Higher intake of cruciferous vegetables was also associated with a decreased risk (P for trend = 0.03); the multivariate RR was 0.67 (95% CI, 0.40-1.11) for women who consumed greater than or equal to five servings per week as compared with those consuming less than two servings per week. These associations were slightly attenuated when we additionally adjusted for intake of beef, pork, or lamb as a main dish. Intake of dietary fiber from vegetable sources was related to a reduced risk; the multivariate RR was 0.54 (95% CI, 0.34-0.87) for women in the highest quintile as compared with those in the lowest quintile (P for trend = 0.01), and it was slightly attenuated with additional adjustment for saturated and trans unsaturated fats. However, we observed no associations between intakes of specific dietary carotenoids, vitamins A, C, E, and folate, and non-Hodgkin's lymphoma risk. Higher intake of vegetables, particularly cruciferous vegetables, may reduce the risk of non-Hodgkin's lymphoma among women.     

Intakes of fruits, vegetables, vitamins A, C, and E, and carotenoids and risk of renal cell cancer.

BACKGROUND: Fruits and vegetables rich in antioxidants have been proposed to reduce the risk of renal cell cancer. However, few prospective studies have examined the intakes of fruits, vegetables, and antioxidant vitamins in relation to the risk of renal cell cancer. METHODS: We prospectively examined the associations between the intakes of fruits, vegetables, vitamins A, C, and E, and carotenoids and risk of renal cell cancer in women and men. We followed 88,759 women in the Nurses' Health Study from 1980 to 2000, and 47,828 men in the Health Professionals Follow-up Study from 1986 to 2000. We assessed dietary intake every 2 to 4 years using a validated semiquantitative food frequency questionnaire. The Cox proportional hazards model was used to estimate study-specific multivariate relative risks (RR), which were pooled using a random effects model. RESULTS: A total of 248 (132 women and 116 men) incident renal cell cancer cases were ascertained during 2,316,525 person-years of follow-up. The consumption of fruits and vegetables was associated with a decreased risk of renal cell cancer in men (multivariate RR, 0.45; 95% CI, 0.25-0.81, for >or=6 servings of fruit and vegetable intake/d versus <3 servings/d; P test for trend = 0.02), but not in women (multivariate RR, 1.17; 95% CI, 0.66-2.07, for the same contrast; P test for trend = 0.25; P test for between-studies heterogeneity = 0.02). Intakes of vitamins A and C from food and carotenoids were inversely associated with the risk of renal cell cancer in men only, but we cannot exclude the possibility that this was due to other factors in fruit and vegetables. No clear association was observed for vitamin E in women or men. CONCLUSIONS: Fruit and vegetable consumption may reduce the risk of renal cell cancer in men.     

Fruit and vegetable intake and incidence of bladder cancer in a male prospective cohort

BACKGROUND: Previous epidemiologic studies of fruit and vegetable intake and bladder cancer risk have yielded inconsistent results, especially with regard to the types of fruits and vegetables consumed. We examined total fruit and vegetable intake, as well as intakes of subtypes of fruits and vegetables, in relation to bladder cancer risk in a large male prospective cohort study. METHODS: Two hundred fifty-two cases of incident bladder cancer were diagnosed from 1986 through January 31, 1996, among 47,909 men enrolled in the Health Professionals Follow-up Study. Each participant in this cohort completed a 131-item food-frequency questionnaire in 1986 and subsequently in 1990 and 1994. We used logistic regression analyses to examine fruit and vegetable intake in relation to bladder cancer risk, after adjusting for age, history of cigarette smoking, current smoking status, geographic region, total fluid intake, and caloric intake. RESULTS: We observed a weak, inverse association that was not statistically significant between total fruit and vegetable intake and bladder cancer risk. Intake of cruciferous vegetables was inversely associated with risk (relative risk = 0.49; 95% confidence interval = 0.32-0.75, for the highest category of cruciferous vegetable intake compared with the lowest), but intakes of yellow or green leafy vegetables or carotenoid-rich vegetables were not associated with risk. Individual cruciferous vegetables, except for coleslaw, were all inversely related to bladder cancer risk, but only the associations for broccoli and cabbage were statistically significant. CONCLUSIONS: Data from this study indicate that high cruciferous vegetable consumption may reduce bladder cancer risk, but other vegetables and fruits may not confer appreciable benefits against this cancer.     

Vegetable intake is associated with reduced breast cancer recurrence in tamoxifen users: a secondary analysis from the Women’s Healthy Eating and Living Study

The protective effect of vegetables on the risk of breast cancer recurrence is uncertain. We sought to evaluate the association between breast cancer recurrence and vegetable intake including analyses stratified on tamoxifen use. Experimental evidence of anti-carcinogenic activity of phytochemicals in cruciferous vegetables in combination with tamoxifen led to specific evaluation of this class of vegetables as well. To assess the association between vegetable intake and breast cancer recurrence, vegetable intake from repeat 24-h dietary recalls were examined as a secondary analysis of 3,080 breast cancer survivors enrolled in the Women’s Healthy Eating and Living (WHEL) Study. At the time of enrollment women were, on average, 23.5 months post-diagnosis. The hazard of recurrence, controlling for relevant and significant clinical and demographic variables, with vegetable intake was assessed overall and separately for women taking tamoxifen. WHEL participants reported mean baseline intakes ( [`(\text x)]{\bar{\text {x}}}, SE) of 3.1 ± 0.05 and 0.5 ± 0.02 servings/day of total and cruciferous vegetables, respectively. Baseline vegetable intake in the highest as compared to lowest tertiles was associated with an overall lower adjusted hazard ratios (HR) for recurrence of 0.69, 95% CI 0.55–0.87. Among women taking tamoxifen, the HRs were 0.56, 95% CI 0.41–0.77 for total vegetables and 0.65, 95% CI 0.47–0.89 for cruciferous vegetable intake. The hazard in women using tamoxifen who reported cruciferous vegetable intake above the median and who were within the highest tertile of total vegetable intake was HR 0.48; 95% CI 0.32–0.70. This secondary analysis in over 3,000 breast cancer survivors suggests that baseline vegetable intake may be associated with a reduction in the risk of breast cancer recurrent or new events particularly for those using tamoxifen. Such associations should be explored further as the possibility that vegetable intake is simply a surrogate for other health-promoting behaviors cannot be ruled out.     

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.     

Fruit and vegetable consumption in relation to pancreatic cancer risk: a prospective study.

High consumption of fruits and vegetables has been associated with a lower risk of pancreatic cancer in many case-control studies. However, cohort studies on this relationship are limited and do not support an association. We examined the associations of overall consumption of fruits and vegetables and consumption of certain subgroups of fruits and vegetables with the incidence of pancreatic cancer among 81,922 women and men in the Swedish Mammography Cohort and the Cohort of Swedish Men. Hazard ratios (HR) with 95% confidence intervals (95% CI) were estimated using Cox proportional hazards models. During an average follow-up of 6.8 years (1998-2004), 135 incident pancreatic cancer cases were diagnosed. After adjustment for age and other risk factors for pancreatic cancer, the HRs for the highest compared with the lowest category of intake were 1.13 (95% CI, 0.66-1.94) for total fruits and vegetables, 1.10 (95% CI, 0.64-1.88) for total fruits, and 1.08 (95% CI, 0.63-1.85) for total vegetables. Among specific subgroups of fruits and vegetables, a nonsignificant inverse association was observed with cruciferous vegetable consumption (> or = 3 servings/wk versus <1 serving/wk: HR, 0.70; 95% CI, 0.43-1.13). Cabbage consumption was associated with a statistically significant lower risk of pancreatic cancer (> or = 1 serving/wk versus never consumption: HR, 0.62; 95% CI, 0.39-0.99). Findings from this prospective study do not support a relationship of overall fruit and vegetable consumption with pancreatic cancer risk. The association between consumption of cruciferous vegetables and pancreatic cancer risk warrants further investigation.     

Fruits and vegetables are associated with lower lung cancer risk only in the placebo arm of the beta-carotene and retinol efficacy trial (CARET).

Despite the unexpected results from the beta-Carotene and Retinol Efficacy Trial (CARET) and similar supplementation trials showing that supplementation with beta-carotene increased, rather than decreased, lung cancer incidence, considerable interest remains in investigating how other compounds in fruits and vegetables may affect lung cancer risk. We used data from 14,120 CARET participants who completed food frequency questionnaires to examine associations of diet with lung cancer risk. After 12 years of follow-up (1989-2001), 742 participants developed lung cancer. We used Cox proportional hazards models to estimate multivariate relative risks (RRs) and 95% confidence intervals (CIs). Analyses were controlled for smoking, asbestos exposure, and other covariates. Analyses of specific botanical groups were also controlled for total fruit and vegetable intake. All models were stratified by CARET treatment arm, and all statistical tests were two-sided. Statistically significant associations of fruit and vegetable intake with lower lung cancer risk were restricted to the CARET placebo arm. The RR for highest versus lowest quintile of total fruit consumption in the placebo arm was 0.56 (95% CI, 0.39-0.81) with a two-sided P for trend = 0.003. Two specific botanical groups were associated with reduced risk of lung cancer. Compared with the lowest quintile of rosaceae fruit consumption, placebo participants in the top quintile had a RR of 0.63 (95% CI, 0.42-0.94; P for trend = 0.02); for cruciferae vegetables, the RR was 0.68 (95% CI, 0.45-1.04; P for trend = 0.01). We did not observe any statistically significant associations of fruit and vegetable intake with lung cancer risk among participants randomized to receive the CARET supplements (30 mg of beta-carotene and 25,000 IU of retinyl palmitate). This report provides evidence that plant foods have an important preventive influence in a population at high risk for lung cancer. However, persons who use beta-carotene supplements do not benefit from the protective compounds in plant foods.     

Fruits and vegetables and prostate cancer: no association among 1104 cases in a prospective study of 130544 men in the European Prospective Investigation into Cancer and Nutrition (EPIC)

We examined the association between self-reported consumption of fruits and vegetables and prostate cancer risk in the European Prospective Investigation into Cancer and Nutrition (EPIC). Data on food consumption and complete follow-up for cancer incidence were available for 130544 men in 7 countries recruited into EPIC between 1993 and 1999. After an average of 4.8 years of follow-up, there were 1104 incident cases of prostate cancer. The associations of consumption of total fruits, total vegetables, cruciferous vegetables and combined total fruits and vegetables with prostate cancer risk were examined using Cox regression, stratified for recruitment center and adjusted for height, weight and energy intake. There was a wide range in consumption of fruits and vegetables: mean intakes (g/day) in the bottom and top fifths of the distribution, as estimated from 24-hr recalls in a subsample of participants, were 53.2 and 410.7 for fruits, 97.1 and 242.1 for vegetables and 169.0 and 633.7 for fruits and vegetables combined. No significant associations between fruit and vegetable consumption and prostate cancer risk were observed. Relative risks (95% confidence intervals) in the top fifth of the distribution of consumption, compared to the bottom fifth, were 1.06 (0.84-1.34) for total fruits, 1.00 (0.81-1.22) for total vegetables and 1.00 (0.79-1.26) for total fruits and vegetables combined; intake of cruciferous vegetables was not associated with risk. These results suggest that total consumption of fruits and vegetables is not associated with the risk for prostate cancer.     

Vegetable and fruit intake and pancreatic cancer in a population-based case-control study in the San Francisco bay area.

Pancreatic cancer is one of the most devastating and rapidly fatal cancers, yet little is known about the primary cause and prevention of this disease. We conducted a population-based case-control study to investigate the association between vegetables and fruits and pancreatic cancer. Between 1995 and 1999, 532 cases and 1,701 age- and sex-matched controls completed direct interviews using a semiquantitative food-frequency questionnaire. No proxy interviews were conducted. We observed inverse associations between consumption of total and specific vegetables and fruits and the risk of pancreatic cancer. The odds ratio and 95% confidence interval for the highest versus the lowest quartile of total vegetable intake was 0.45 (0.32-0.62), trend P < 0.0001; and for total fruits and fruit juice was 0.72 (0.54-0.98), trend P = 0.06. Odds ratios and 95% confidence intervals for the highest versus the lowest quartile of specific vegetables and fruits were: 0.63 (0.47-0.83) for dark leafy vegetables, 0.76 (0.56-1.0) for cruciferous vegetables, 0.59 (0.43-0.81) for yellow vegetables, 0.56 (0.41-0.76) for carrots, 0.51 (0.38-0.70) for beans, 0.46 (0.33-0.63) for onions and garlic, and 0.78 (0.58-1.0) for citrus fruits and juice. Compared with less than five servings per day of total vegetables and fruits combined, the risk of pancreatic cancer was 0.49 (0.36-0.68) for more than nine servings per day. These results suggest that increasing vegetable and fruit consumption, already recommended for the prevention of several other chronic diseases, may impart some protection against developing pancreatic cancer.     

Intakes of fruits and vegetables,carotenoids and vitamins A,E, C in relation to the risk of bladder cancer in the ATBC cohort study

We examined the relation between dietary fruit and vegetables, carotenoids and vitamin intakes and the risk of bladder cancer among male smokers in a prospective cohort study. Over a median of 11 years, we followed 27 111 male smokers aged 50-69 years who were initially enrolled in the Alpha-Tocopherol Beta-Carotene Cancer Prevention Study. During this period, 344 men developed bladder cancer. All of these men had completed a 276-food item dietary questionnaire at baseline. Cox proportional hazards models were used to estimate the relative risks and 95% confidence intervals and to simultaneously adjust for age, smoking history, energy intake and intervention group. Consumption of fruits and vegetables was not associated with the risk of bladder cancer (relative risk=1.28; 95% confidence intervals CI: 0.89-1.84, for highest vs lowest quintile). Similarly, no associations were observed for groups of fruits or vegetables (berries and cruciferous vegetables), or for specific fruits and vegetables. Dietary intakes of alpha-carotene, beta-carotene, lycopene, lutein/zeaxanthin, beta-cryptoxanthin, vitamins A, E, and C, and folate were not related to the risk of bladder cancer. These findings suggest that fruit and vegetable intakes are not likely to be associated with bladder cancer risk. However, these results may not be generalisable to non-smokers.     

Vegetables,fruit and risk of gastric cancer in Japan: a 10-year follow-up of the JPHC Study Cohort I

The association between vegetables and fruit consumption and gastric cancer risk was investigated in a population-based prospective study in 4 public health center areas in Japan. Dietary and other exposure data were obtained in 1990 from a cohort of 19,304 men and 20,689 women with a self-administered questionnaire. After 10 years of follow-up, a total of 404 cases of gastric cancer were documented among them. After adjustment for age, gender, areas and other potential confounding factors and after exclusion of the cases diagnosed in first and second follow-up years, the relative risk associated with intake 1 or more days per week compared to less than 1 day per week was 0.64 (95% CI 0.45-0.92) for yellow vegetable, 0.48 (95% CI 0.25-0.89) for white vegetable and 0.70 (95% CI 0.49-1.00) for fruit. Relative risks associated with quintile of total vegetable consumption were 1.00, 0.86, 0.75, 0.90 and 0.75 (p for trend = 0.17). In the differentiated type of gastric cancer, the association became clearer: 1.00, 0.96, 0.78, 0.88 and 0.53 (p for trend = 0.03). This prospective study suggests that vegetable and fruit intake, even in low amounts, is associated with a lower risk of gastric cancer. Although no striking differences in the association were seen between cardia and noncardia cancer, an inverse association was higher in differentiated rather than in undifferentiated types of gastric cancer.     

Fruit and vegetable consumption and incidence of gastric cancer: a prospective study.

BACKGROUND: Whether fruit and vegetable consumption may confer protection from gastric cancer remains controversial. METHODS: We prospectively investigated the association between consumption of fruits and vegetables and the incidence of gastric cancer among participants from two population-based cohort studies: 36,664 women in the Swedish Mammography Cohort and 45,338 men in the Cohort of Swedish Men. Participants completed a food-frequency questionnaire in 1997 and were followed up for cancer incidence through June 2005. Cox proportional hazards models were used to estimate multivariate hazard ratios (HR) and 95% confidence intervals (95% CI). RESULTS: During a mean follow-up of 7.2 years, we ascertained 139 incident cases of gastric cancer. Vegetable consumption was inversely associated with risk of gastric cancer, whereas no significant association was observed for fruit consumption. After controlling for age and other risk factors, women and men who consumed > or =2.5 servings/d of vegetables had a HR of 0.56 (95% CI, 0.34-0.93) for developing gastric cancer compared with those who consumed <1 serving/d. The respective HR for fruit consumption was 0.86 (95% CI, 0.52-1.43). Among specific subgroups of vegetables, consumption of green leafy vegetables and root vegetables was inversely associated with risk of gastric cancer; the multivariate HRs comparing > or =3 servings/wk with <0.5 serving/wk were 0.64 (95% CI, 0.42-0.99) for green leafy vegetables and 0.43 (95% CI, 0.27-0.69) for root vegetables. CONCLUSIONS: Frequent consumption of vegetables may reduce the risk of gastric cancer.     

Fruit and vegetable consumption and risk of bladder cancer: a prospective cohort study

Fruit and vegetable consumption has been inconsistently associated with risk of bladder cancer. We used data from a prospective population-based cohort study of 82,002 Swedish women and men to examine the association between fruit and vegetable consumption and bladder cancer incidence. Diet was assessed with a validated food frequency questionnaire. During a mean follow-up of 9.4 years, 485 incident cases of bladder cancer were identified in the Swedish cancer registries. We found no statistically significant association between intakes of total fruits and vegetables, total fruits, or total vegetables and bladder cancer risk after adjustment for age, sex, education, and cigarette smoking. The multivariate rate ratios (95% confidence intervals) comparing the highest with the lowest quartile of intake were 0.80 (0.60-1.05) for total fruits and vegetables, 0.93 (0.69-1.25) for fruits, and 0.89 (0.67-1.19) for vegetables. Likewise, no associations were observed for citrus fruits, cruciferous vegetables, or green leafy vegetables. The associations did not differ by sex or smoking status. In conclusion, findings from this prospective study suggest that fruit and vegetable intakes are not likely to be appreciably associated with the risk of bladder cancer.     

Fruits and vegetables and renal cell carcinoma: findings from the European prospective investigation into cancer and nutrition (EPIC)

We examined the association between fruits and vegetables and risk of renal cell carcinoma (RCC) in the European Prospective Investigation into Cancer and Nutrition (EPIC). Dietary intake data and complete follow-up information on cancer incidence were available for 375,851 participants recruited in EPIC centers of 8 countries. During an average follow-up of 6.2 years, 306 incident cases of RCC were identified. The associations of consumption of total vegetables, total fruits, combined total fruits and vegetables and specific subtypes of vegetables with RCC risk were analyzed using Cox proportional hazards, stratified by centre and adjusted for potential confounders. No significant associations between fruit and vegetable consumption and RCC risk were observed despite a wide range of intake. The estimated relative risks (95% confidence intervals [CI]) in men and women combined were 0.97 (0.85-1.11) per 40 g increase in vegetable intake, 1.03 (0.97-1.08) per 40 g increase in fruit intake and 1.02 (0.93-1.11) per 80 g increase in fruit and vegetable intake combined. Among the vegetable subtypes, an inverse association was observed for root vegetables (RR per 8 g increase: 0.88; 95% CI: 0.78-0.99). These results suggest that total consumption of fruits and vegetables is not related to risk of RCC, although we cannot exclude the possibility that very low consumption is related to higher risk. The relationship of specific fruit and vegetable subgroups with RCC risk warrant further investigation.     

A prospective study of tomato products, lycopene, and prostate cancer risk

BACKGROUND: Some data, including our findings from the Health Professionals Follow-Up Study (HPFS) from 1986 through January 31, 1992, suggest that frequent intake of tomato products or lycopene, a carotenoid from tomatoes, is associated with reduced risk of prostate cancer. Overall, however, the data are inconclusive. We evaluated additional data from the HPFS to determine if the association would persist. METHODS: We ascertained prostate cancer cases from 1986 through January 31, 1998, among 47 365 HPFS participants who completed dietary questionnaires in 1986, 1990, and 1994. We used pooled logistic regression to compute multivariate relative risks (RR) and 95% confidence intervals (CIs). All statistical tests were two-sided. RESULTS: From 1986 through January 31, 1998, 2481 men in the study developed prostate cancer. Results for the period from 1992 through 1998 confirmed our previous findings---that frequent tomato or lycopene intake was associated with a reduced risk of prostate cancer. Similarly, for the entire period of 1986 through 1998, using the cumulative average of the three dietary questionnaires, lycopene intake was associated with reduced risk of prostate cancer (RR for high versus low quintiles = 0.84; 95% CI = 0.73 to 0.96; P(trend) =.003); intake of tomato sauce, the primary source of bioavailable lycopene, was associated with an even greater reduction in prostate cancer risk (RR for 2+ servings/week versus <1 serving/month = 0.77; 95% CI = 0.66 to 0.90; P(trend)<.001), especially for extraprostatic cancers (RR = 0.65; 95% CI = 0.42 to 0.99). These associations persisted in analyses controlling for fruit and vegetable consumption and for olive oil use (a marker for Mediterranean diet) and were observed separately in men of Southern European or other Caucasian ancestry. CONCLUSION: Frequent consumption of tomato products is associated with a lower risk of prostate cancer. The magnitude of the association was moderate enough that it could be missed in a small study or one with substantial errors in measurement or based on a single dietary assessment.