Fruit and vegetable consumption and colorectal adenomas in the Nurses' Health Study

Consumption of fruits and vegetables may confer protection from colorectal adenomas, but the limited observational and interventional evidence is inconclusive. We examined the association between fruit and vegetable consumption and the prevalence and incidence of adenomas of the distal colon and rectum in the Nurses' Health Study (NHS). We used data from 34,467 women in the NHS who had undergone colonoscopy or sigmoidoscopy during follow-up between 1980 and 1998. Consumption of fruits and vegetables was assessed in 1980, 1984, 1986, 1990, and 1994 using a semiquantitative food frequency questionnaire; 1,720 prevalent cases of adenoma of the distal colon and rectum were diagnosed between 1980 and 1998. Frequent consumption of fruit was inversely related to the risk of being diagnosed with polyps, whereas little association was found for vegetable consumption. Women who reported consuming five or more servings of fruit a day had an odds ratio (OR) of 0.60 [95% confidence interval (95% CI), 0.44-0.81] for developing colorectal adenomas compared with women who consumed only one or fewer servings of fruit per day, after adjustment for relevant covariates (P(trend) = 0.001). The respective OR for vegetable consumption was 0.82 (95% CI, 0.65-1.05; P(trend) = 0.1). Women who consumed four or more servings of legumes per week had a lower incidence of colorectal adenomas than women who reported consuming one serving per week or less (OR, 0.67; 95% CI, 0.51-0.90; P(trend) = 0.005). Frequent consumption of fruit may reduce the risk of colorectal adenomas.     

Fruit and vegetable consumption in relation to ovarian cancer incidence: the Swedish Mammography Cohort

We prospectively examined the incidence of epithelial ovarian cancer and its subtypes in relation to baseline fruit and vegetable consumption in the Swedish Mammography Cohort, a population-based cohort study of 61 084 women aged 38-76 years in 1987-1990. During an average follow-up of 13.5 years, 266 incident cases of invasive epithelial ovarian cancer were diagnosed. After adjustment for potential confounders, we observed a statistically significant inverse association between consumption of vegetables and ovarian cancer risk (P-value for trend=0.01); the multivariate rate ratio (RR) for the comparison of three or more servings of vegetables per day with one or fewer servings per day was 0.61 (95% confidence interval (CI), 0.38-0.97). For fruit consumption a modest, not statistically significant, positive association was found (P-value for trend=0.07); the multivariate RR for the highest compared with the lowest category of consumption being 1.37 (95% CI, 0.90-2.06). The associations with fruit and vegetable consumption did not vary by subtype of ovarian cancer. These findings suggest that high consumption of vegetables, but not of fruits, may reduce the risk of ovarian 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.     

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.     

Vegetable and fruit consumption and risk of renal cell carcinoma: results from the Netherlands cohort study

Vegetable and fruit consumption is generally inversely associated with various cancer types, including renal cell carcinoma (RCC). The Netherlands cohort study on diet and cancer (NLCS) consists of 120,852 men and women, aged 55-69 years, who filled out a self-administered questionnaire that includes 150-item food-frequency questions and additional questions on lifestyle factors, at baseline in 1986. A case-cohort approach was used. After 9.3 years of follow-up, 275 microscopically confirmed incident cases were identified. Subjects with incomplete or inconsistent dietary data were excluded, leaving 260 RCC cases for analyses on fruit consumption and 249 RCC cases for analyses on vegetable consumption. Incidence rate ratios (RR) and corresponding 95% confidence intervals (CI) were estimated using Cox proportional hazard models. RRs for exposure variables are expressed per increment of 25 g/day and are adjusted for age, sex, smoking, body mass index and history of hypertension at baseline. The RRs for vegetable consumption were further adjusted for fruit consumption and vice versa. Total vegetable and fruit consumption (RR: 1.00; 95% CI 0.97-1.02), vegetable (RR: 1.00, 95% CI 0.96-1.06) and fruit consumption (RR: 1.00; 95% CI 0.97-1.03) were not associated with RCC risk. Also, no association existed for botanical subgroups of vegetables and fruit. For 30 individual vegetables and fruits, we observed one that significantly increased RR (mandarin consumption, RR: 1.76; 95% CI 1.28-2.42), which must be regarded cautiously because of multiple testing. These results suggest the absence of an association between vegetable and/or fruit consumption and RCC risk.     

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.     

Dietary carotenoids and vitamins A, C, and E and risk of breast cancer

BACKGROUND: Data on intake of specific carotenoids and breast cancer risk are limited. Furthermore, studies of vitamins A, C, and E in relation to breast cancer risk are inconclusive. We have conducted a large, prospective study to evaluate long-term intakes of these nutrients and breast cancer risk. METHODS: We examined, by use of multivariate analysis, associations between intakes of specific carotenoids, vitamins A, C, and E , consumption of fruits and vegetables, and breast cancer risk in a cohort of 83234 women (aged 33-60 years in 1980) who were participating in the Nurses' Health Study. Through 1994, we identified 2697 incident cases of invasive breast cancer (784 premenopausal and 1913 postmenopausal). RESULTS: Intakes of beta-carotene from food and supplements, lutein/zeaxanthin, and vitamin A from foods were weakly inversely associated with breast cancer risk in premenopausal women. Strong inverse associations were found for increasing quintiles of alpha-carotene, beta-carotene, lutein/zeaxanthin, total vitamin C from foods, and total vitamin A among premenopausal women with a positive family history of breast cancer. An inverse association was also found for increasing quintiles of beta-carotene among premenopausal women who consumed 15 g or more of alcohol per day. Premenopausal women who consumed five or more servings per day of fruits and vegetables had modestly lower risk of breast cancer than those who had less than two servings per day (relative risk [RR] = 0.77; 95% confidence interval [CI] = 0.58-1.02); this association was stronger among premenopausal women who had a positive family history of breast cancer (RR = 0.29; 95% CI = 0.13-0.62) or those who consumed 15 g or more of alcohol per day (RR = 0.53; 95% CI = 0.27-1.04). CONCLUSIONS: Consumption of fruits and vegetables high in specific carotenoids and vitamins may reduce premenopausal breast cancer risk.     

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.     

MGMT genotype modulates the associations between cigarette smoking, dietary antioxidants and breast cancer risk

O(6)-methylguanine DNA methyl-transferase (MGMT) is the only known critical gene involved in cellular defense against alkylating agents in the DNA direct reversal repair (DRR) pathway. Three single nucleotide polymorphism (SNP) coding for non-conservative amino acid substitutions have been identified [C250T (Leu84Phe), A427G (Ile143Val) and A533G (Lys178Arg)]. To examine the importance of the DRR pathway in risk for breast cancer and the potential interaction with cigarette smoking and dietary antioxidants, we genotyped for these variants using biospecimens from the Long Island Breast Cancer Study Project. Genotyping was performed by a high throughput assay with fluorescence polarization and included 1067 cases and 1110 controls. Overall, there was no main effect between any variant genotype, haplotype or diplotype and breast cancer risk. Heavy smoking (>31 pack-year) significantly increased breast cancer risk for women with the codon 84 variant T-allele [odds ratio, OR = 3.0, 95% confidence interval (95% CI) = 1.4-6.2]. An inverse association between fruits and vegetables consumption and breast cancer risk was observed among women with the wild-type genotype for codon 84 (OR = 0.8, 95% CI = 0.6-0.9 for > or =35 servings of fruits and vegetables per week and CC genotype versus those with <35 servings per week and CC genotype). The association between fruits and vegetables consumption and reduced breast cancer risk was apparent among women with at least one variant allele for codon 143 (OR = 0.6, 95% CI = 0.5-0.9 for > or =35 servings of fruits and vegetables per week and AG or GG genotype versus those with <35 servings per week and AA genotype). Similar patterns were observed for dietary alpha-carotene and supplemental beta-carotene, but not for supplemental vitamins C and E. These data suggest that polymorphisms in MGMT may modulate the inverse association previously observed between fruits and vegetables consumption, dietary antioxidants and breast cancer risk, and support the importance of fruits and vegetables on breast cancer risk reduction.     

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.     

Alcohol consumption and risk of renal cell carcinoma: a prospective study of Swedish women

Previous literature, although not consistent, suggests that moderate alcohol consumption might be associated with decreased risk of renal cell carcinoma (RCC) in women. Thus, we examined the association between alcohol intake and the incidence of RCC by analyzing data from the Swedish Mammography Cohort, a population-based prospective cohort of 59,237 women, aged 40-76 years, who, at baseline in 1987-1990, were cancer free and had completed a food-frequency questionnaire including questions about alcohol consumption. Through June 30, 2004, 132 incident cases of RCC were diagnosed. We used the Cox proportional hazards model to estimate age and body mass index (BMI) adjusted rate ratios (RRs) and their 95% confidence intervals (CIs). Women who consumed >4.3 grams per day of alcohol (ethanol) had nonsignificantly lower risk of RCC than did women who consumed <2.5 g/d (RR = 0.71, 95% CI 0.42-1.19); among women > or = 55 years of age at entry into the cohort, corresponding risk estimates were RR = 0.33, 95% CI 0.10-1.05, p for trend = 0.04 and among women with BMI >25 kg/m2, RR = 0.30, 95% CI 0.09-0.97, p for trend = 0.04. Consistent with these findings, women who drank 1 or more servings of total alcoholic beverages per week had lower RCC risk than did women who drank less (RR = 0.62, 95% CI 0.41-0.94); the corresponding estimate for women > or = 55 years of age was RR = 0.44, 95% CI 0.22-0.88. Results from our prospective cohort study of middle-aged and elderly women indicate that moderate alcohol consumption may be associated with decreased risk of RCC.     

Prospective study of fruit and vegetable consumption and incidence of colon and rectal cancers

BACKGROUND: Frequent consumption of fruit and vegetables has been associated with a reduced risk of colorectal cancer in many observational studies. METHODS: We prospectively investigated the association between fruit and vegetable consumption and the incidence of colon and rectal cancers in two large cohorts: the Nurses' Health Study (88 764 women) and the Health Professionals' Follow-up Study (47 325 men). Diet was assessed and cumulatively updated in 1980, 1984, 1986, and 1990 among women and in 1986 and 1990 among men. The incidence of cancer of the colon and rectum was ascertained up to June or January of 1996, respectively. Relative risk (RR) estimates were calculated with the use of pooled logistic regression models accounting for various potential confounders. All statistical tests were two-sided. RESULTS: With a follow-up including 1 743 645 person-years and 937 cases of colon cancer, we found little association of colon cancer incidence with fruit and vegetable consumption. For women and men combined, a difference in fruit and vegetable consumption of one additional serving per day was associated with a covariate-adjusted RR of 1.02 (95% confidence interval [CI] = 0.98-1.05). A difference in vegetable consumption of one additional serving per day was associated with an RR of 1.03 (95% CI = 0.97-1.09). Similar results were obtained for women and men considered separately. A difference in fruit consumption of one additional serving per day was associated with a covariate-adjusted RR for colon cancer of 0.96 (95% CI = 0.89-1.03) among women and 1. 08 (95% CI = 1.00-1.16) among men. For rectal cancer (total, 244 cases), a difference in fruit and vegetable consumption of one additional serving per day was associated with an RR of 1.02 (95% CI = 0.95-1.09) in men and women combined. None of these associations was modified by vitamin supplement use or smoking habits. CONCLUSIONS: Although fruits and vegetables may confer protection against some chronic diseases, their frequent consumption does not appear to confer protection from colon or rectal cancer.     

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.     

Consumption of vegetables and fruits and risk of ovarian carcinoma

BACKGROUND: To the authors' knowledge, only a few prospective studies to date have investigated the correlation between vegetable and fruit consumption and the risk of ovarian carcinoma and their results have been inconclusive. METHODS: Vegetable and fruit intake was assessed in relation to ovarian carcinoma, among 62,573 postmenopausal women participating in The Netherlands Cohort Study on Diet and Cancer. Women reported on dietary habits and on other risk factors for cancer in a self-administered questionnaire in 1986. Follow-up of cancer was implemented by annual record linkage with The Netherlands Cancer Registry and a pathology register. After 11.3 years of follow-up, data regarding 252 incident invasive epithelial ovarian carcinoma cases and of 2216 subcohort members were available for case-cohort analyses. RESULTS: Multivariable-adjusted rate ratios (RR) of ovarian carcinoma for women in the highest compared with the lowest quintile of intake (RR(Q5 vs. Q1)) were 0.98 (95% confidence interval [95% CI], 0.61-1.58) for total vegetables and 1.11 (95% CI, 0.70-1.78) for total fruit. The RR(Q5 vs. Q1) values of ovarian carcinoma with intake of cooked vegetables, raw vegetables, brassicas, legumes, cooked leafy vegetables, and raw leafy vegetables were 1.35 (95% CI, 0.83-2.21), 0.75 (95% CI, 0.48-1.18), 1.42 (95% CI, 0.88-2.29), 0.93 (95% CI, 0.60-1.44), 1.05 (95% CI, 0.66-1.67), and 1.23 (95% CI, 0.75-2.02), respectively. With the exception of raw endive (multivariable-adjusted RR, 0.24; 95% CI, 0.07-0.78), none of the individual vegetable or fruit items showed a statistically significant association with ovarian carcinoma. CONCLUSIONS: The results of the current study did not support a significant association between vegetable or fruit consumption and ovarian carcinoma risk in a cohort of postmenopausal women.     

A prospective study of diet and stomach cancer mortality in United States men and women.

Frequent consumption of fruits, vegetables, and whole grains has been associated with a reduced risk of stomach cancer in the majority of case-control studies of these factors: however, prospective studies have been less consistent. We examined the association between selected major food groups (citrus fruits, vegetables, whole grains, and processed meats) and risk of fatal stomach cancer in the Cancer Prevention Study (CPS) II cohort of 1.2 million United States men and women. During 14 years of follow-up, we documented 439 stomach cancer deaths in women and 910 in men after exclusion of individuals with prevalent cancers, inadequate diet information, and recent weight loss at baseline in 1982. After controlling for other risk factors, none of the food groups examined were associated with risk of stomach cancer except for an unexpected increased risk with vegetable consumption in women [relative risk (RR) = 1.25; 95% confidence interval (CI), 0.99-1.58; highest versus lowest tertile, P = 0.06 for trend]. A high overall plant food intake (a sum of vegetables, citrus fruit, and whole grains) was associated with reduced risk in men (RR = 0.79; 95% CI, 0.67-0.93; highest versus lowest tertile, P = 0.003 for trend), but not in women (RR = 1.18; 95% CI, 0.93-1.50; P = 0.16 for trend). Of individual foods examined, liver consumption greater than twice/week was associated with an increased risk of fatal stomach cancer in women (RR = 1.96; 95% CI, 1.09-3.53) and men (RR = 1.63; 95% CI, 1.02-2.62) compared with nonconsumers. This study supports a modest role for plant foods in reducing the risk of fatal stomach cancer in men, but not in women.     

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.     

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.     

Fruits, vegetables and breast cancer risk: a systematic review and meta-analysis of prospective studies

Evidence for an association between fruit and vegetable intake and breast cancer risk is inconclusive. To clarify the association, we conducted a systematic review and meta-analysis of the evidence from prospective studies. We searched PubMed for prospective studies of fruit and vegetable intake and breast cancer risk until April 30, 2011. We included fifteen prospective studies that reported relative risk estimates and 95 % confidence intervals (CIs) of breast cancer associated with fruit and vegetable intake. Random effects models were used to estimate summary relative risks. The summary relative risk (RR) for the highest versus the lowest intake was 0.89 (95 % CI: 0.80-0.99, I (2) = 0 %) for fruits and vegetables combined, 0.92 (95 % CI: 0.86-0.98, I (2) = 9 %) for fruits, and 0.99 (95 % CI: 0.92-1.06, I (2) = 20 %) for vegetables. In dose-response analyses, the summary RR per 200 g/day was 0.96 (95 % CI: 0.93-1.00, I (2) = 2 %) for fruits and vegetables combined, 0.94 (95 % CI: 0.89-1.00, I (2) = 39 %) for fruits, and 1.00 (95 % CI: 0.95-1.06, I (2) = 17 %) for vegetables. In this meta-analysis of prospective studies, high intake of fruits, and fruits and vegetables combined, but not vegetables, is associated with a weak reduction in risk of breast cancer.     

Fruits and vegetables and ovarian cancer risk in a pooled analysis of 12 cohort studies.

Because fruits and vegetables are rich in bioactive compounds with potential cancer-preventive actions, increased consumption may reduce the risk of ovarian cancer. Evidence on the association between fruit and vegetable intake and ovarian cancer risk has not been consistent. We analyzed and pooled the primary data from 12 prospective studies in North America and Europe. Fruit and vegetable intake was measured at baseline in each study using a validated food-frequency questionnaire. To summarize the association between fruit and vegetable intake and ovarian cancer, study-specific relative risks (RR) were estimated using the Cox proportional hazards model, and then combined using a random-effects model. Among 560,441 women, 2,130 cases of invasive epithelial ovarian cancer occurred during a maximum follow-up of 7 to 22 years across studies. Total fruit intake was not associated with ovarian cancer risk-the pooled multivariate RR for the highest versus the lowest quartile of intake was 1.06 [95% confidence interval (95% CI), 0.92-1.21; P value, test for trend = 0.73; P value, test for between-studies heterogeneity = 0.74]. Similarly, results for total vegetable intake indicated no significant association (pooled multivariate RR, 0.90; 95% CI, 0.78-1.04, for the highest versus the lowest quartile; P value, test for trend = 0.06; P value, test for between-studies heterogeneity = 0.31). Intakes of botanically defined fruit and vegetable groups and individual fruits and vegetables were also not associated with ovarian cancer risk. Associations for total fruits and vegetables were similar for different histologic types. These results suggest that fruit and vegetable consumption in adulthood has no important association with the risk of ovarian 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.