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.     

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.     

Meta-analysis of studies on breast cancer risk and diet: the role of fruit and vegetable consumption and the intake of associated micronutrients

A meta-analysis was carried out, in order to summarise published data on the relationship between breast cancer, fruit and vegetable consumption and/or the intake of beta-carotene and vitamin C. Relative risks were extracted from 26 published studies from 1982 to 1997. Random and fixed effects models were used. Between studies, heterogeneity was found for vegetables, fruit, vitamin C but not for beta-carotene. Summary relative risk (RR) estimates based upon a random effects model, except for beta-carotene, for 'high consumption' compared with 'low consumption', derived from the studies satisfying the inclusion criteria were as follows: vegetable consumption: RR=0.75 (95% CI (confidence interval) 0.66-0.85) from 17 studies; fruit consumption: RR=0.94 (95% CI 0.79-1.11) from 12 studies; vitamin C: RR=0.80 (95% CI 0.68-0.95) from 9 studies; beta-carotene: RR=0.82 (95% CI 0.76-0.91) from 11 studies. This analysis confirms the association between intake of vegetables and, to a lesser extent, fruits and breast cancer risk from published sources. Increasing vegetable consumption might reduce the risk of breast cancer.     

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.     

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.     

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.     

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.     

Increased consumption of fruit and vegetables and future cancer incidence in selected European countries

Cancer is one of the major causes of death in western countries. Fruit and vegetable consumption may reduce the risk of cancers of the oropharynx, oesophagus, lung, stomach and colorectum. We investigated the potential effect of interventions aimed at increasing the intake of fruits and vegetables to the recommended level (500 g/d) on future cancer incidence in Europe. Data on cancer incidence and daily intake of fruit and vegetables were compiled for France, Germany, The Netherlands, Spain and Sweden. We also performed a meta-analysis of European observational studies to arrive at a quantitative estimate on the association between fruit and vegetable intake and cancer risk. Predictions on the future cancer incidence were modelled using PREVENT 3.01. Our study predicted 212,000 fruit- and vegetable-related cancer cases in these countries in 2050, out of which 398 (0.19%) might be prevented if the 500 g/d fruit and vegetable intake were achieved in the aforementioned countries. The largest absolute impact was observed for lung cancer with 257 (out of 136,517) preventable cases if the intervention was successfully implemented. Sweden would benefit the most from intervention to increase fruit and vegetable consumption with a 2% reduction in expected cases. Increasing fruit and vegetable consumption has a small impact on reducing the burden of cancer in Europe. Health impact assessment tools such as PREVENT can provide the basis for decision making in chronic disease prevention.     

Fruit and vegetable consumption and lung cancer risk: updated information from the European Prospective Investigation into Cancer and Nutrition (EPIC)

The association of fruit and vegetable consumption and lung cancer incidence was evaluated using the most recent data from the European Prospective Investigation into Cancer and Nutrition (EPIC), applying a refined statistical approach (calibration) to account for measurement error potentially introduced by using food frequency questionnaire data. Between 1992 and 2000, detailed information on diet and life-style of 478,590 individuals participating in EPIC was collected. During a median follow-up of 6.4 years, 1,126 lung cancer cases were observed. Multivariate Cox proportional hazard models were applied for statistical evaluation. In the whole study population, fruit consumption was significantly inversely associated with lung cancer risk while no association was found for vegetable consumption. In current smokers, however, lung cancer risk significantly decreased with higher vegetable consumption; this association became more pronounced after calibration, the hazard ratio (HR) being 0.78 (95% CI 0.62-0.98) per 100 g increase in daily vegetable consumption. In comparison, the HR per 100 g fruit was 0.92 (0.85-0.99) in the entire cohort and 0.90 (0.81-0.99) in smokers. Exclusion of cases diagnosed during the first 2 years of follow-up strengthened these associations, the HR being 0.71 (0.55-0.94) for vegetables (smokers) and 0.86 (0.78-0.95) for fruit (entire cohort). Cancer incidence decreased with higher consumption of apples and pears (entire cohort) as well as root vegetables (smokers). In addition to an overall inverse association with fruit intake, the results of this evaluation add evidence for a significant inverse association of vegetable consumption and lung cancer incidence in smokers.     

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.     

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 consumption and lung cancer risk in the Netherlands Cohort Study on Diet and Cancer

Objective: The purpose was to study the association between vegetable and fruit consumption and lung cancer incidence using 1074 cases after 6.3 years of follow-up in the Netherlands Cohort Study. Methods: Dietary intake was assessed using a 150-item food-frequency questionnaire. Multivariate models were used including age, sex, family history of lung cancer, highest educational level attained, and smoking history. Results: Statistically significant inverse associations were found with total vegetables and most vegetable groups. Rate ratios (RRs) based on consumption frequency showed the strongest effect of vegetables from the Brassica group (RR 0.5, 95% confidence interval (95% CI) 0.3–0.9, for consumption 3 times per week versus once a month). RR of highest versus lowest quintile of total vegetable consumption was 0.7 (95% CI 0.5–1.0, p-trend 0.001). Statistically significant inverse associations were found for all fruits listed in the questionnaire. RRs for quintiles of total fruit intake were 1.0, 0.7, 0.6, 0.6 and 0.8 respectively (p-trend < 0.0001). Protective effects of fruits and vegetables were stronger in current than in former smokers, and weaker for adenocarcinomas than for other types of tumors. Conclusions: Inverse associations with lung cancer are found for both vegetable and fruit intake, but no specific type of vegetable or fruit seems to be particularly responsible.     

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.     

Consumption of vegetables and fruits and urothelial cancer incidence: a prospective study.

Although most epidemiological studies concerning urothelial cancer support a possible protective effect of vegetable and fruit consumption, previous studies have been inconsistent with regard to which vegetables and fruits may be responsible for an inverse association. The association between the consumption of 21 vegetables and nine fruits and urothelial cancer risk was assessed in the Netherlands Cohort Study among 120,852 men and women aged 55-69 years at baseline in 1986. After 6.3 years of follow-up, 538 incident cases and 2,953 subcohort members with complete vegetable data and 569 cases and 3,123 subcohort members with complete fruit data were available for case-cohort analyses. In multivariable case-cohort analyses, the following age-, sex-, and smoking-adjusted incidence rate ratios for groups of vegetable and fruit consumption were observed (comparing highest versus lowest quintile of consumption): total vegetables, 0.91 [95% confidence interval (CI): 0.65-1.27]; cooked vegetables, 0.98 (CI: 0.71-1.35); raw vegetables, 1.10 (CI: 0.78-1.53); cooked leafy vegetables, 0.89 (CI: 0.65-1.23); raw leafy vegetables, 0.94 (CI: 0.73-1.22); pulses, 1.03 (CI: 0.74-1.44); brassicas, 0.75 (CI: 0.54-1.04); allium vegetables, 0.89 (CI: 0.67-1.19); total fruit, 0.74 (CI: 0.53-1.04); and citrus fruit, 0.85 (CI: 0.62-1.17). For three separate items (cauliflower, cooked carrots, and mandarins), a statistically significant inverse association was seen, whereas for other specific vegetables or fruit, no statistically significant association was observed. The data are suggestive of an inverse association between the consumption of brassicas, total fruit, and urothelial cancer risk, whereas total vegetable consumption did not appear to be associated with urothelial cancer risk.     

Lung cancer risk and red meat consumption among Iowa women

OBJECTIVE: Some epidemiologic studies suggest that diets high in total fat, saturated fat, or cholesterol are associated with increased risk of lung cancer. Others suggest that diets high in red meat consumption, particularly well-done red meat, are a lung cancer risk factor. In Iowa, we had the opportunity to investigate concurrently the role of meat intake and macronutrients in lung cancer etiology. METHODS: A population-based case-control study of both non-smoking and smoking women was conducted in Iowa. A 70-item food frequency questionnaire (FFQ) was completed by 360 cases and 574 frequency-matched controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using logistic regression. Multivariate models included age, education, pack-years of smoking, yellow-green vegetable intake, fruit/fruit juice intake, nutrient density calories, previous non-malignant lung disease, alcohol consumption and body mass index (BMI). RESULTS: When comparing the fifth (highest) to the first (lowest) quintile of consumption of total fat, saturated fat and cholesterol, we obtained odds ratios of 2.0 (1.3-3.1), 3.0 (1.9-4.7), and 2.0 (1.3-3.0) respectively. However, when red meat was entered into the model along with total fat, saturated fat or cholesterol, the excess risk for the macronutrients disappeared while an odds ratio of 3.3 (1.7-7.6) was obtained for red meat. The odds ratios for red meat consumption were similar among adenocarcinoma cases, OR=3.0 (1.1-7.9) and non-adenocarcinoma cases, OR=3.2 (1.3-8.3) and among life-time nonsmokers and ex-smokers OR=2.8 (1.4-5.4), and current smokers, OR=4.9 (1.1-22.3). Yellow-green vegetables were protective with an odds ratio of 0.4 (0.2-0.7). CONCLUSIONS: Consumption of red meat, was associated with an increased risk of lung cancer even after controlling for total fat, saturated fat, cholesterol, fruit, yellow-green vegetable consumption and smoking history, while yellow-green vegetables are associated with a decreased risk of lung 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.     

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.     

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.