Cohort analysis of fruit and vegetable consumption and lung cancer mortality in European men

Diet as a Factor Supporting Lung Cancer Treatment-A Systematic Review

The purpose of this study was to summarize the evidence from epidemiological studies concerning associations between diet and the effectiveness of treatment for lung cancer. For this review, a literature search has been conducted in the EMBASE and PubMed databases, including papers published between 1977 and June 2022. The term "lung cancer" was used in conjunction with "diet". Footnotes from the selected papers were also analyzed. The present study is in line with the recommendations included in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. The review included studies involving adults, including randomized controlled trials (RCTs) and cohort and observational studies. In total, 863 papers were found, with duplicates excluded. Ultimately, 20 papers were reviewed. The present systematic review indicates that vitamin A, ascorbic acid (vitamin C), vitamin E, selenium, and zinc-as antioxidants-can strengthen the body's antioxidant barrier. Furthermore, preoperative immunonutrition may not only improve perioperative nutritional status following induction chemoradiotherapy in lung cancer surgery patients but also reduce the severity of postoperative complications. Similarly, a protein supply may exert a beneficial effect on human health by increasing average body weight and muscle mass. Omega-3 fatty acid content in the diet and the consumption of their main source, fish, may have some regulatory effect on inflammation in patients with lung cancer treated with chemotherapy and radiotherapy. In addition, n-3 fatty acids inhibit tumor cell proliferation and may reduce the toxicity of chemotherapy. Increased energy and protein intake are strongly associated with improved quality of life, functional outcomes, hand grip strength, symptoms, and performance in patients with lung cancer. The use of a supportive diet should be the standard of care, alongside pharmaceutical therapy, in treatment for patients with lung cancer.

Dietary habits of lung cancer patients from the Lower Silesia region of Poland

AIM OF THE STUDY

Assessment of lung cancer patients' dietary habits before treatment enable medical staff to provide more individual, precise and complex care to patients, taking into consideration their nutritional status. The aim of this study was, therefore, to evaluate dietary habits related to lung cancer risk of lung cancer patients in comparison with controls from the Lower Silesia region of Poland.

MATERIAL AND METHODS

Assessments of dietary habits, based on a validated questionnaire related to lung cancer risk were performed on 92 lung cancer patients and compared with the results obtained in 157 controls. Dietary patterns were evaluated concerning on eating frequency of high- and low- glycemic index products, vegetables and fruits, vegetable and fruit juices, green tea, liquid dairy products, meat and fried products over the previous year. Alcohol consumption was assessed on a dichotomous scale (yes or no).

RESULTS

Majority of patients had inappropriate dietary habits, such as low consumption of low GI cereal products, vegetables, fruit and green tea, and a high consumption frequency of fried products.

CONCLUSIONS

Reported dietary mistakes indicate the need for dietary education among people at lung cancer risk and with newly diagnosed disease, to enhance their nutritional status.

The effect of fruit and vegetable intake on the development of lung cancer: a meta-analysis of 32 publications and 20,414 cases

BACKGROUND/OBJECTIVES

Quantification of the association between the intake of vegetables and fruits and the risk of lung cancer is controversial. Thus, we conducted a meta-analysis to assess the relationship between vegetables and fruits and lung cancer risk.

SUBJECTS/METHODS

Pertinent studies were identified by a search in PubMed and Web of Knowledge. Random-effects models were used to calculate summary relative risks (RR) and the corresponding 95% confidence intervals (CI). Publication bias was estimated using Begg's test.

RESULTS

Finally, 30 articles with 37 studies comprising of 20,075 lung cancer cases for vegetables intake with lung cancer risk and 31 articles with 38 studies comprising of 20,213 lung cancer cases for fruits intake with lung cancer risk were included in this meta-analysis. The combined results showed that there were significant associations between vegetables and fruits intake and lung cancer risk. The pooled RR were 0.74 (95% CI: 0.67, 0.82) for vegetables and 0.80 (95% CI: 0.74, 0.88) for fruits. Significant association was found in females on vegetables intake and lung cancer but not in males. The association was also stronger in females than males on fruits intake and lung cancer risk. No publication bias was detected.

CONCLUSIONS

Our analysis indicated that intake of vegetables and fruits may have a protective effect on lung cancer, and the associations were stronger in females. As the potential biases and confounders could not be ruled out completely in this meta-analysis, further studies are needed.

How the Seven Countries Study contributed to the definition and development of the Mediterranean diet concept: a 50-year journey

The Seven Countries Study of Cardiovascular Diseases was started at the end of the 1950s and it continues to be run after >50 years. It enrolled, at entry, 16 population cohorts in eight nations of seven countries for a total of 12,763 middle-aged men. It was the prototype of epidemiological studies seeking cultural contrasts and the first to compare cardiovascular disease (CVD) rates related to diet differences. The study has shown that populations suffer widely different incidence and mortality rates from coronary heart disease (CHD) as well as from other CVDs and overall mortality. Higher rates were found in North America and northern Europe, and lower rates in southern Europe - Mediterranean countries - and Japan. These differences in CHD rates were strongly associated with different levels of saturated fat consumption and average serum cholesterol levels, with lowest rates in Greece and Japan where the total fat intake was very different. The cohorts were also different in dietary patterns defined by the ratio of calories derived from plant foods and fish on the one hand and calories derived from animal foods and sugar on the other. These findings pointed to the so-called Mediterranean diet, which is characterized by large values of that plant/animal ratio, a pattern associated with lower incidence and mortality from CHD and also with the lowest death rates and the greatest survival rates. More recent studies have refined these concepts and documented on a larger scale the virtues of these eating habits.

Fruit and vegetable consumption and mortality from all causes, cardiovascular disease, and cancer: systematic review and dose-response meta-analysis of prospective cohort studies

OBJECTIVE

To examine and quantify the potential dose-response relation between fruit and vegetable consumption and risk of all cause, cardiovascular, and cancer mortality.

DATA SOURCES

Medline, Embase, and the Cochrane library searched up to 30 August 2013 without language restrictions. Reference lists of retrieved articles.

STUDY SELECTION

Prospective cohort studies that reported risk estimates for all cause, cardiovascular, and cancer mortality by levels of fruit and vegetable consumption.

DATA SYNTHESIS

Random effects models were used to calculate pooled hazard ratios and 95% confidence intervals and to incorporate variation between studies. The linear and non-linear dose-response relations were evaluated with data from categories of fruit and vegetable consumption in each study.

RESULTS

Sixteen prospective cohort studies were eligible in this meta-analysis. During follow-up periods ranging from 4.6 to 26 years there were 56,423 deaths (11,512 from cardiovascular disease and 16,817 from cancer) among 833,234 participants. Higher consumption of fruit and vegetables was significantly associated with a lower risk of all cause mortality. Pooled hazard ratios of all cause mortality were 0.95 (95% confidence interval 0.92 to 0.98) for an increment of one serving a day of fruit and vegetables (P=0.001), 0.94 (0.90 to 0.98) for fruit (P=0.002), and 0.95 (0.92 to 0.99) for vegetables (P=0.006). There was a threshold around five servings of fruit and vegetables a day, after which the risk of all cause mortality did not reduce further. A significant inverse association was observed for cardiovascular mortality (hazard ratio for each additional serving a day of fruit and vegetables 0.96, 95% confidence interval 0.92 to 0.99), while higher consumption of fruit and vegetables was not appreciably associated with risk of cancer mortality.

CONCLUSIONS

This meta-analysis provides further evidence that a higher consumption of fruit and vegetables is associated with a lower risk of all cause mortality, particularly cardiovascular mortality.

Dietary intake of fruits and vegetables and overall survival in non-Hodgkin lymphoma

In a cohort of 301 patients with non-Hodgkin lymphoma (NHL), we examined whether the pre-diagnostic consumption of fruits and vegetables, or of nutrients concentrated in fruits and vegetables, was associated with overall survival (OS). Proportional hazards models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for all-cause mortality. A total of 91 deaths occurred in the patient cohort over a median follow-up period of 8.2 years. No association with OS was detected for a dietary pattern characterized by high intakes of fruits, vegetables and starch; fruit intake; vegetable intake; or nutrient intake in patients diagnosed with overall NHL, follicular lymphoma or diffuse large B-cell lymphoma. Higher intakes of carotene-rich vegetables (HR = 0.4 [0.2-1.0]; p trend = 0.05) and α-carotene (HRT3 vs. T1 = 0.4 [0.2-0.9]; p trend = 0.03) were associated with better OS among ever smokers. Overall, our data suggest that the intake of fruits and vegetables prior to diagnosis is not associated with OS in patients with NHL.

Dimovski A. Natural antioxidants in cancer prevention

It is well known that oxidative stress is an inevitable event in aerobic life. When our cells use oxygen to create energy, a variety of reactive oxygen (ROS) and nitrogen species (RNS) are generated. These species could attack DNA directly and form mutagenic lesions afterwards. According to the oxidative stress hypothesis of aging, the oxidative damage to critical molecules accumulates over the life period and could ultimately impair the body’s function. Moreover, severe oxidative stress causes mutations of tumor suppressor genes, known as one of the initial events in carcinogenesis. Furthermore, it could also play a crucial role in the promotion of the multi-step carcinogenesis. On the other hand, the human body possesses a number of mechanisms that counteract oxidative stress by producing antioxidants in situ, or externally supplied them through foods and/or supplements. Indeed, a considerable amount of laboratory evidence from chemical, cell culture, and animal studies indicates that antioxidants may slow down or possibly prevent the cancer development. Yet, the information from recent cohort, case-control and/or ecological studies is less clear. Therefore, the objectives of this review are to compile a compendium of studies, and to identify effective and promising natural antioxidant interventions.

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.

Variety in fruit and vegetable consumption and the risk of lung cancer in the European prospective investigation into cancer and nutrition

BACKGROUND

We investigated whether a varied consumption of vegetables and fruits is associated with lower lung cancer risk in the European Prospective Investigation into Cancer and Nutrition study.

METHODS

After a mean follow-up of 8.7 years, 1,613 of 452,187 participants with complete information were diagnosed with lung cancer. Diet diversity scores (DDS) were used to quantify the variety in fruit and vegetable consumption. Multivariable proportional hazards models were used to assess the associations between DDS and lung cancer risk. All models were adjusted for smoking behavior and the total consumption of fruit and vegetables.

RESULTS

With increasing variety in vegetable subgroups, risk of lung cancer decreases [hazard ratios (HR), 0.77; 95% confidence interval (CI), 0.64-0.94 highest versus lowest quartile; P trend = 0.02]. This inverse association is restricted to current smokers (HR, 0.73; 95% CI, 0.57-0.93 highest versus lowest quartile; P trend = 0.03). In continuous analyses, in current smokers, lower risks were observed for squamous cell carcinomas with more variety in fruit and vegetable products combined (HR/two products, 0.88; 95% CI, 0.82-0.95), vegetable subgroups (HR/subgroup, 0.88; 95% CI, 0.79-0.97), vegetable products (HR/two products, 0.87; 95% CI, 0.79-0.96), and fruit products (HR/two products, 0.84; 95% CI, 0.72-0.97).

CONCLUSION

Variety in vegetable consumption was inversely associated with lung cancer risk among current smokers. Risk of squamous cell carcinomas was reduced with increasing variety in fruit and/or vegetable consumption, which was mainly driven by the effect in current smokers.

IMPACT

Independent from quantity of consumption, variety in fruit and vegetable consumption may decrease lung cancer risk.

Fruits and vegetables consumption and the risk of histological subtypes of lung cancer in the European Prospective Investigation into Cancer and Nutrition (EPIC)

Objective

To examine the association between fruit and vegetable consumption and risk of different histological subtypes of lung cancer among participants of the European Prospective Investigation into Cancer and Nutrition study.

Methods

Multivariable Cox proportional hazard models were used to analyze the data. A calibration study in a subsample was used to reduce dietary measurement errors.

Results

During a mean follow-up of 8.7 years, 1,830 incident cases of lung cancer (574 adenocarcinoma, 286 small cell, 137 large cell, 363 squamous cell, 470 other histologies) were identified. In line with our previous conclusions, we found that after calibration a 100 g/day increase in fruit and vegetables consumption was associated with a reduced lung cancer risk (HR 0.94; 95% CI 0.89–0.99). This was also seen among current smokers (HR 0.93; 95% CI 0.90–0.97). Risks of squamous cell carcinomas in current smokers were reduced for an increase of 100 g/day of fruit and vegetables combined (HR 0.85; 95% CI 0.76–0.94), while no clear effects were seen for the other histological subtypes.

Conclusion

We observed inverse associations between the consumption of vegetables and fruits and risk of lung cancer without a clear effect on specific histological subtypes of lung cancer. In current smokers, consumption of vegetables and fruits may reduce lung cancer risk, in particular the risk of squamous cell carcinomas.

The effects of nutrition-related factors on four-year mortality among a biracial sample of community-dwelling elders in the North Carolina piedmont

The purpose of this epidemiological study was to estimate mortality risk associated with poor diet quality (consumption of five food groups), extremes of body mass index (BMI), waist circumference, and impaired food-related activities of daily living among community-dwelling older Black and White men and women. The design of the current study was a retrospective-prospective cohort study. The sample included residents (n = 1920) of five North Carolina Piedmont counties. The dependent variable was four-year all-cause mortality. Analyses were stratified by gender and race, and controlled covariates included: age, living with others, income, smoking and alcohol use, cognitive status, and overall self-rated health. Data were self-reported to interviewers, except BMI and waist, which were measured by trained interviewers. Difficulty in fixing meals elevated the risk of mortality between 2.7 and 6.5 times across the four gender-race groups. Among older adults, inability to fix a meal conferred more risk of mortality than did lack of financial means. Adequate servings of vegetables were uniformly protective, although significant only among Black males. Neither BMI nor waist circumference conferred significant mortality risk. These population-based findings suggest relationships between nutrition risk factors and mortality that are unique and require further focused studies.

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.

Fruit and vegetables in cancer prevention

Our aim was to review the epidemiological literature on possible cancer-preventive effects of the consumption of fruits and vegetables in humans, to quantify the effect of high versus low consumption of fruits and vegetables, and to give an overall assessment of the existing evidence. We based our work on an expert meeting conducted by the International Agency for Research on Cancer in 2003. A qualitative reading and evaluation of relevant articles on the cancer-preventive effect of the consumption of fruits and vegetables was made followed by the calculation of the mean relative risk and range for cohort and case-control studies separately. The possible population-preventable fraction for modifying diet in relation to fruit and vegetable consumption was calculated as well as an overall statement about the degree of evidence for the cancer-preventive effect of fruit and vegetable consumption for each cancer site. There is limited evidence for a cancer-preventive effect of the consumption of fruits and vegetables for cancer of the mouth and pharynx, esophagus, stomach, colon-rectum, larynx, lung, ovary (vegetables only), bladder (fruit only), and kidney. There is inadequate evidence for a cancer-preventive effect of the consumption of fruits and vegetables for all other sites. Applying this range of risk difference to the range of prevalence of low intake, the preventable fraction for low fruit and vegetable intake would fall into the range of 5-12%. It is important to recognize that this is only a crude range of estimates and that the proportion of cancers that might be preventable by increasing fruit and vegetable intake may vary beyond this range for specific cancer sites and across different regions of the world.

Effects of benzyl and phenethyl isothiocyanate on P450s 2A6 and 2A13: potential for chemoprevention in smokers

Isothiocyanates have been shown to be potent inhibitors of carcinogenesis in animals exposed to a number of chemical carcinogens including the tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). In this study the effects of benzyl isothiocyanate (BITC) and phenethyl isothiocyanate (PEITC), two naturally occuring isothiocyanates, on P450 2A6 and 2A13 were investigated. P450s 2A6 and 2A13 are thought to be the primary human P450 enzymes responsible for the in vivo metabolism of nicotine and NNK, respectively. In vitro, BITC and PEITC efficiently inhibited P450 2A6- and 2A13-mediated coumarin 7-hydroxylation. The inhibition of P450 2A6 and 2A13 by BITC was non-competitive with KI's of 4.1 and 1.3 microM, respectively. PEITC was a more potent inhibitor of both enzymes than BITC, with a KI of 0.37 microM for P450 2A6 and 0.03 microM for P450 2A13. P450 2A6-mediated metabolism of nicotine and P450 2A13-mediated alpha-hydroxylation of NNK were also inhibited significantly by these two isothiocyanates. Both BITC and PEITC were able to inactivate P450 2A6 and 2A13 in an NADPH-dependent manner potentially through the formation of adducts to the apoprotein. The potent inhibition of P450 2A6- and 2A13-mediated metabolisms together with the ability of BITC and PEITC to inactivate the enzymes suggests the possibility that these isothiocyanates could be developed as chemopreventive agents to protect smokers who are unwilling or unable to quit smoking against lung cancer.

Effects of Cruciferous Vegetable Consumption on Urinary Metabolites of the Tobacco-Specific Lung Carcinogen 4-(Methylnitrosamino)-1-(3-Pyridyl)-1-Butanone in Singapore Chinese

Vegetable consumption, including cruciferous vegetables, is protective against lung cancer, but the mechanisms are poorly understood. The purpose of this study was to investigate the effects of cruciferous vegetable consumption on the metabolism of the tobacco-specific lung carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) in smokers. The study was carried out in Singapore Chinese, whose mean daily intake of cruciferous vegetables is three times greater than that of people in the United States. Eighty-four smokers provided urine samples and were interviewed about dietary habits using a structured questionnaire, which included questions on consumption of nine commonly consumed cruciferous vegetables. Samples of these vegetables obtained in Singapore markets at three different times of year were analyzed for glucosinolates. Urine was analyzed for metabolites of NNK: 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) and its glucuronides (NNAL-Glucs). Glucobrassicins, which release indole-3-carbinols on chewing, were the major glucosinolates in seven of the nine cruciferous vegetables, accounting for 70.0% to 93.2% of all glucosinolates in these vegetables. There was a significant correlation (P = 0.01) between increased consumption of glucobrassicins and decreased levels of NNAL in urine after adjustment for number of cigarettes smoked per day; similar trends were observed for NNAL-Glucs (P = 0.08) and NNAL plus NNAL-Glucs (P = 0.03). These results are consistent with those of previous studies, which demonstrate that indole-3-carbinol decreases levels of urinary NNAL probably by inducing hepatic metabolism of NNK. The results are discussed with respect to the known chemopreventive activity of indole-3-carbinol against lung tumorigenesis by NNK in mice and the effects of isothiocyanates, which are also formed on consumption of cruciferous vegetables, on NNK metabolism. The results of this study demonstrate the complexities in assessing effects of cruciferous vegetables on carcinogen metabolism.

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 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.

Epidemiologic evidence of the protective effect of fruit and vegetables on cancer risk

BACKGROUND

Diets rich in fruit and vegetables have been recommended for preventing cancer. The evidence supporting this recommendation is based on observational studies, although results of several prospective studies have cast some doubts on whether fruit and vegetables are associated with cancer risk reduction.

OBJECTIVE

We sought to summarize evidence from case-control and prospective studies on fruit and vegetable intake and cancer risk with a meta-analytic approach.

DESIGN

Published case-control and cohort studies that reported on total vegetable and fruit intake and risk of cancer of several sites were included. Relative risks were estimated by using linear logistic regression models.

RESULTS

Case-control studies overall support a significant reduction in the risks of cancers of the esophagus, lung, stomach, and colorectum associated with both fruit and vegetables; breast cancer is associated with vegetables but not with fruit; and bladder cancer is associated with fruit but not with vegetables. The overall relative risk estimates from cohort studies suggest a protective effect of both fruit and vegetables for most cancer sites considered, but the risk reduction is significant only for cancers of the lung and bladder and only for fruit.

CONCLUSIONS

Prospective studies provide weaker evidence than do case-control studies of the association of fruit and vegetable consumption with reduced cancer risk. The discrepancies may be related to recall and selection biases in case-control studies. In contrast, the association may have been underestimated in prospective studies because of the combined effects of imprecise dietary measurements and limited variability of dietary intakes within each cohort.

Vegetable intake and long-term survival among middle-aged men in Italy

PURPOSE

To examine prospectively the relationship between vegetable consumption and long-term survival.

METHODS

In 1965, a total of 1536 Italian males from two Italian rural cohorts of the Seven Countries Study, aged 45-65 years, were examined. Information on lifestyle and food consumption collected at this visit, and total and cause-specific mortality data collected in 30 years of follow-up were analyzed for the present study.

RESULTS

During a period of 30 years, 1096 deaths occurred (308 from coronary heart disease, 325 from cancer, 158 from cerebrovascular disease and 305 from all other causes). The age-adjusted life expectancy for men consuming more than 60 g/day of vegetables was nearly 2 years longer than for men consuming less than 20 g/day. This increase in survival was more striking in smokers than nonsmokers (2.1 vs. a 1 year gain). The association also held for both geographic cohorts, although the pattern of vegetable consumption was very different in the two villages.

CONCLUSIONS

The results suggest a positive association between vegetable intake and life expectancy. Vegetable intake may be especially protective for smokers although the biological explanation for such an effect is unclear.

Biologic damage resulting from exposure to tobacco smoke and from radon: implication for preventive interventions

Cigarette smoking and residential radon are, respectively, the first and second leading cause of lung cancer in the United States today. Of the approximately 157 000 lung deaths occurring in 2000, approximately 90% can be attributed to cigarette smoking and 30% of the lung cancer deaths among non-smokers can be attributed to residential radon exposure. Although dwarfed by cigarette related lung cancer, lung cancer among lifetime non-smokers is a leading cause of death in the United States, and many other countries, accounting for approximately 16 000 deaths per year in the US. Laboratory studies and epidemiological investigations, particularly those conducted in the past decade, are yielding evidence that tobacco smoke and radon may share important elements of lung cancer's pathologic mechanism(s). Lung cancer prevention among smokers, ex-smokers and lifetime nonsmokers can be enhanced as we learn more about the etiologic mechanism(s) of lung cancer resulting from these and other exposures including diet, non-malignant respiratory diseases, occupational exposures, and susceptibility-gene. In this article we review both laboratory and epidemiologic data that gives insight into the biologic damage done to the lung from these exposures.

A dietary oxidative balance score of vitamin C, beta-carotene and iron intakes and mortality risk in male smoking Belgians

The purpose of this study was to investigate, in smokers, whether the oxidative balance of their dietary pattern affected mortality risk. To evaluate the oxidative balance of the dietary pattern, an oxidative balance score was constructed that summarized the combined intake of dietary antioxidants (vitamin C and beta-carotene) and a prooxidant (iron). The low oxidative balance score group included smokers with a diet high in vitamin C and beta-carotene and/or low in iron and the high oxidative balance score group included those with a diet low in vitamin C and beta-carotene and/or high in iron. Using the 10-y follow-up mortality data from the Belgian Interuniversity Research on Nutrition and Health (BIRNH) study, the association of this oxidative balance score with all-cause, cardiovascular disease (CVD) and total cancer mortality was investigated in 2814 male smokers. In multivariate-adjusted Cox models, men in the highest oxidative balance score group had a higher relative risk (RR) of all-cause [RR = 1.44, 95% confidence interval (CI): 1.13, 1.82] and of total cancer mortality (RR = 1.62, 95% CI: 1.07, 2.45) compared with men in the lowest score group. This association was less pronounced for CVD mortality risk and was not significant (RR = 1.31, 95% CI: 0.86, 2.00). The risk of all-cause and total cancer mortality was driven principally by the high score group, which suggested a threshold effect for risk rather than a linear trend. The findings are consistent with the hypothesis that the oxidative balance of the diet is associated with subsequent mortality. Smokers whose diet is unbalanced in terms of anti- and prooxidants may therefore benefit from a recommendation to consume more servings of fresh fruits and vegetables and less meat.

An estimate of premature cancer mortality in the U.S. due to inadequate doses of solar ultraviolet-B radiation

BACKGROUND

There are large geographic gradients in mortality rates for a number of cancers in the U.S. (e.g., rates are approximately twice as high in the northeast compared with the southwest). Risk factors such as diet fail to explain this variation. Previous studies have demonstrated that the geographic distributions for five types of cancer are related inversely to solar radiation. The purpose of the current study was to determine how many types of cancer are affected by solar radiation and how many premature deaths from cancer occur due to insufficient ultraviolet (UV)-B radiation.

METHODS

UV-B data for July 1992 and cancer mortality rates in the U.S. for between 1970-1994 were analyzed in an ecologic study.

RESULTS

The findings of the current study confirm previous results that solar UV-B radiation is associated with reduced risk of cancer of the breast, colon, ovary, and prostate as well as non-Hodgkin lymphoma. Eight additional malignancies were found to exhibit an inverse correlation between mortality rates and UV-B radiation: bladder, esophageal, kidney, lung, pancreatic, rectal, stomach, and corpus uteri. The annual number of premature deaths from cancer due to lower UV-B exposures was 21,700 (95% confidence interval [95% CI], 20,400-23,400) for white Americans, 1400 (95% CI, 1100-1600) for black Americans, and 500 (95% CI, 400-600) for Asian Americans and other minorities.

CONCLUSIONS

The results of the current study demonstrate that much of the geographic variation in cancer mortality rates in the U.S. can be attributed to variations in solar UV-B radiation exposure. Thus, many lives could be extended through increased careful exposure to solar UV-B radiation and more safely, vitamin D3 supplementation, especially in nonsummer months.