Do Tobacco and Alcohol Modify Protective Effects of Diet on Oral Carcinogenesis?

Recent systematic reviews concluded that the frequent consumption of fruits and vegetables is inversely associated with the risk of oral cancer. We assessed this association, specifically comparing results obtained to nonsmokers and smokers, as well to nondrinkers and drinkers. We conducted a case-control study involving 296 patients with oral squamous cell carcinoma (cases) attended in 3 major hospitals of São Paulo, Brazil, paired with 296 controls, recruited from outpatient units of the same hospitals. Multivariate models assessed the effect of fruits and salads according to smoking and drinking. The intake of fruit was associated with the prevention of the disease in the specific assessment among light [odds ratio (OR) = 0.46; 95% confidence interval (CI) = 0.27–0.78) and heavy (OR = 0.30; 95% CI = 0.14–0.65) smokers. The same was observed for vegetables consumption. For nonsmokers, no fruit (OR = 50; 95% CI = 0.22–1.12) or vegetable (for tomato, OR = 0.53; 95% CI = 0.31–0.93) was associated with reduced risk of oral and oropharyngeal cancer. Similar results were found in the stratified analysis according to drinking status with OR = 0.51 (95% CI = 0.30–0.87) and 0.18 for fruits (95% CI = 0.07–0.45), respectively, for light and heavy drinkers. This observation suggests that the protective effect of fruit and salad intake may modulate the deleterious effects from tobacco and alcohol.     

Risk for oral cancer associated to smoking, smokeless and oral dip products

Oral cancer is one of the most common life threatening diseases in India. Tobacco and alcohol are considered to be the most risk factors for oral cancer. This study was conducted to investigate the association of tobacco and poly-ingredient oral dip products with oral cancer. A case-control study of 350 cases and 350 controls, over a period of 19 months, between February 2005 and September 2006 was carried out in Pune, India. The self-reported information about the consumption of tobacco, poly-ingredient oral dip products, alcohol, dietary habits and demographic status were collected by a researcher made questionnaire. Univariate and multivariate analysis were used to identify the risk of substances abuse. The frequency of smoking, smokeless and oral dip products in cases were significantly higher than controls (P < 0.0001). Among smoking types, bidi (P < 0.0001, OR = 4.1 95% CI = 2.4 - 6.9), of smokeless types, chewing tobacco (P < 0.0001, OR = 8.3, 95% CI = 5.4 - 13.0) and mishiri (P < 0.0001, OR = 3.3, 95% CI =2.1 - 5.4), and of oral dip products, consumption of gutkha (P < 0.0001, OR = 12.8, 95% CI =7.0 - 23.7) and supari (P < 0.0001, OR = 6.6, 95% CI =3.0 - 14.8) indicated strong association with oral cancer upon adjustment. This study provides strong evidence that gutkha, supari -areca nut- chewing tobacco (tobacco flakes), bidi smoking and mishiri (tobacco powder, which applied as a tooth and gum cleaner) are independent risk for oral cancer.     

Carotenoid intake and head and neck cancer: a pooled analysis in the International Head and Neck Cancer Epidemiology Consortium

Food and nutrition play an important role in head and neck cancer (HNC) etiology; however, the role of carotenoids remains largely undefined. We explored the relation of HNC risk with the intake of carotenoids within the International Head and Neck Cancer Epidemiology Consortium. We pooled individual-level data from 10 case–control studies conducted in Europe, North America, and Japan. The analysis included 18,207 subjects (4414 with oral and pharyngeal cancer, 1545 with laryngeal cancer, and 12,248 controls), categorized by quintiles of carotenoid intake from natural sources. Comparing the highest with the lowest quintile, the risk reduction associated with total carotenoid intake was 39 % (95 % CI 29–47 %) for oral/pharyngeal cancer and 39 % (95 % CI 24–50 %) for laryngeal cancer. Intakes of β-carotene equivalents, β-cryptoxanthin, lycopene, and lutein plus zeaxanthin were associated with at least 18 % reduction in the rate of oral and pharyngeal cancer (95 % CI 6–29 %) and 17 % reduction in the rate of laryngeal cancer (95 % CI 0–32 %). The overall protective effect of carotenoids on HNC was stronger for subjects reporting greater alcohol consumption (p < 0.05). The odds ratio for the combined effect of low carotenoid intake and high alcohol or tobacco consumption versus high carotenoid intake and low alcohol or tobacco consumption ranged from 7 (95 % CI 5–9) to 33 (95 % CI 23–49). A diet rich in carotenoids may protect against HNC. Persons with both low carotenoid intake and high tobacco or alcohol are at substantially higher risk of HNC.     

Dietary risk factors for kidney cancer in Eastern and Central Europe

The authors examined the role of diet in the high-risk population of Central Europe among 1,065 incident kidney cancer cases and 1,509 controls in Russia, Romania, Poland, and the Czech Republic. They observed an increased association with kidney cancer for consumption of milk (odds ratio (OR) = 1.46, 95% confidence interval (CI): 1.15, 1.84) and yogurt (OR = 1.34, 95% CI: 1.07, 1.67), as well as all meat (OR = 1.27, 95% CI: 1.06, 1.51 compared with the lowest tertile). High consumption of all vegetables (OR = 0.64, 95% CI: 0.51, 0.80) and cruciferous vegetables (OR = 0.68, 95% CI: 0.55, 0.84) was inversely associated with kidney cancer. In addition, high consumption of preserved vegetables increased the risk of kidney cancer (OR = 1.66, 95% CI: 1.24, 2.21). Alcohol consumption did not appear to be associated with kidney cancer. This 1999-2003 study provides further evidence that diet may play a role in the development of kidney cancer, with a particularly strong protective association for high vegetable intake. The increased risk associated with dairy products, preserved vegetables, and red meat provides clues to the high rates of kidney cancer in this population.     

Raw and cooked vegetables, fruits, selected micronutrients, and breast cancer risk: a case-control study in Germany

In 1998-2000, a case-control study of breast cancer was conducted in Heidelberg, Germany. Three hundred ten consecutively recruited cases with primary breast cancer were matched according to 10-yr age groups to 353 controls with conditions unrelated to diet or endocrine disorders. Intake of raw vegetables, total vegetables, and whole-grain products was inversely associated with breast cancer risk (highest vs. lowest quartile adjusted odds ratio [OR] 0.51, 95% confidence interval [CI] 0.31-0.84; OR = 0.62, 95% CI = 0.38-1.02; and OR = 0.57; 95% CI = 0.34-0.95, respectively). Also, high intake of some selected vitamins and minerals possessing putative DNA-stabilizing properties displayed significant inverse risk associations. Adjusted ORs were as follows: vitamin C (OR = 0.49, 95% CI = 0.2-0.88), folate equivalents (OR = 0.47, 95% CI = 0.25-0.88), b-carotene (OR = 0.46, 95% CI = 0.27-0.80), zinc (OR = 0.35, 95% CI = 0.15-0.78), and copper (OR = 0.51, 95% CI = 0.31-1.03). In contrast, no significant association with risk was seen for an increased intake of fruits, cooked vegetables, fiber, calcium, manganese, or iron. In this population of German women, components of raw vegetables and some micronutrients appear to decrease breast cancer risk.     

Dietary patterns and risk of cancer of the oral cavity and pharynx in Uruguay

From 1995 to 2002, a case-control study on food groups and risk of cancer of the oral cavity and pharynx was conducted in Montevideo, Uruguay. Two hundred thirty cases were frequency-matched to 460 controls on age, residence, and urban/rural status. The study was restricted to men. The relationship between foods and risk of oral and pharyngeal squamous cell carcinoma was examined through: 1) individual food group analysis, 2) factor analysis, and 3) determination of empirical scores. The results were similar. Factor analysis generated 2 patterns, which were labeled as "stew" and "vegetables and fruits." The stew pattern loaded positively on boiled meat, cooked vegetables, potato, and sweet potato. This pattern was directly associated with risk of oral and pharyngeal cancer [odds ratio (OR), 3.75; 95% confidence interval (CI), 1.99-7.06; P value for trend=0.0002]. The vegetables and fruits factor loaded positively on raw vegetables, citrus fruits, other fruits, liver, fish, and desserts. This pattern was inversely associated with risk of oropharyngeal carcinoma (OR, 0.34; 95% CI, 0.18-0.64; P value for trend=0.0008). Joint effects of high intake of risk foods and low intake of protective foods were associated with a risk of 12.0 (95% CI, 4.1-34.6). Our study confirms the important role of dietary factors in oral and pharyngeal cancer risk and suggests that the analysis of dietary patterns is a powerful tool to investigate the links between nutrition and cancer.     

Oral health, hygiene practices and oral cancer

OBJECTIVE: To assess the association between oral health and hygiene practices and oral cancer. METHODS: Hospital-based case-control study in the metropolitan area of S?o Paulo, southeastern Brazil, from 1998 to 2002. A total 309 patients with squamous cell carcinoma of the mouth and the pharynx and 468 controls matched by sex and age were included in the study. Cases were recruited in seven reference hospitals and controls were selected in five out of the seven participating hospitals. Detailed information on smoking, alcohol consumption, schooling, oral health status and hygiene practices were obtained through interviews. Odds ratios (OR) and 95% confidence intervals (95% CI), adjusted by sex, age, schooling, smoking, alcohol consumption as well as the variables oral health status and hygiene practices were estimated using unconditional logistic regression analyses. RESULTS: The use of complete dental prosthesis was not associated with oral cancer but regular gum bleeding showed a strong association (OR 3.1; 95% CI 1.2-7.9). Those who never attended a dental visit were more likely to have oral cancer (OR 2.5; 95% CI 1.3-4.8). Daily mouthwash use showed a stronger association to pharynx (OR 4.7; 95% CI 1.8-12.5) than mouth cancer (OR 3.2; 95% CI 1.6-6.3). CONCLUSIONS: Gum bleeding, no dental care, and daily mouthwash use were factors associated with oral cancer regardless of tobacco and alcohol consumption.     

Occupation and cancer of the oral cavity or oropharynx in Turin, Italy

In a population-based case-referent study, the occupational experience of 86 men with oral or oropharyngeal cancer and 373 referents was analyzed with respect to employment in 41 occupations and 40 industries, as well as to exposure to 16 chemicals, as estimated via a job-exposure matrix. Among the occupations and industries at higher risk were machinery operator (odds ratio [OR] 2.0; 95% confidence interval [95% CI] 1.0-4.0), plumber (OR 5.0, 95% CI 1.2-21.5), building industry (OR 2.5; 95% CI 1.3-4.5), textile industry (OR 2.5; 95% CI 0.6-4.6), and electricity production (OR 2.8; 95% CI 0.7-12.1). All the OR estimates were adjusted for age, education, area of birth, tobacco smoking, and alcohol consumption. An association between formaldehyde exposure and oral cancer was suggested (OR for any exposure 1.6, 95% CI 0.9-2.8; OR for probable or definite exposure 1.8, 95% CI 0.6-5.5). No other chemical included in the matrix showed any risk pattern. The evidence of an association between formaldehyde exposure and oral or oropharyngeal cancer is strengthened by the results of this study.     

Diet diversity and colorectal cancer

BACKGROUND: Food diversity has been recommended to achieve a healthy diet and prevent cancer. The relation between diet diversity and the risk of colorectal cancer was investigated using data from a multicenter case-control study carried out between 1992 and 1996 in Italy. METHODS: The study included 1225 subjects with cancer of the colon (688 men and 537 women), 728 with cancer of the rectum (437 men and 291 women), and 4154 controls (2073 men and 2081 women) residing in the same geographical areas. Odds ratios (ORs) of colon and rectal cancer and the corresponding 95% confidence intervals (CI) according to food diversity were derived from unconditional multiple logistic regression equations. RESULTS: For colon cancer, an inverse association for total diversity was found in males (adjusted OR of 0.65 for the highest vs the lowest quintile of total diversity; 95% CI: 0.46-0.93) and in females (OR = 0.85; 95% CI: 0.57-1.26). With respect to specific food groups, there was an inverse association only with diversity within vegetables (OR = 0.66; 95% CI: 0.54-0.81 in colon cancer and OR = 0.71; 95% CI: 0.55-0.91 in rectal cancer). CONCLUSIONS: This study suggests that total diversity is moderately related to a decreased risk of colorectal cancer risk. A better understanding of the potential influence of dietary patterns on colorectal cancer is needed.     

Oral health and risk of squamous cell carcinoma of the head and neck and esophagus: results of two multicentric case-control studies

Poor oral health has been reported as a risk factor in the etiology of head and neck cancer. Data on oral health were ascertained as part of two multicenter case-control studies comprising 924 cases and 928 controls in central Europe and 2,286 cases and 1,824 controls in Latin America. Incident cases of squamous cell carcinoma of the head and neck (oral cavity, pharynx, larynx) and esophagus, as well as age (in quinquennia)- and sex frequency-matched controls, were enrolled from 1998 to 2003. Poor condition of the mouth (central Europe: odds ratio (OR) = 2.89, 95% confidence interval (CI): 1.74, 4.81; Latin America: OR = 1.89, 95% CI: 1.47, 2.42), lack of toothbrush use (Latin America: OR = 2.36, 95% CI: 1.28, 4.36), and daily mouthwash use (Latin America: OR = 3.40, 95% CI: 1.96, 5.89) emerged as risk factors for head and neck cancer, independent of tobacco use and alcohol consumption. Missing between six and 15 teeth was an independent risk factor for esophageal cancer (central Europe: OR = 2.84, 95% CI: 1.26, 6.41; Latin America: OR = 2.18, 95% CI: 1.04, 4.59). These results indicate that periodontal disease (as indicated by poor condition of the mouth and missing teeth) and daily mouthwash use may be independent causes of cancers of the head, neck, and esophagus.     

Tobacco and alcohol use during pregnancy and risk of oral clefts. Occupational Exposure and Congenital Malformation Working Group

OBJECTIVES: This study examined the relationship between maternal tobacco and alcohol consumption during the first trimester of pregnancy and oral clefts. METHODS: Data were derived from a European multicenter case-control study including 161 infants with oral clefts and 1134 control infants. RESULTS: Multivariate analyses showed an increased risk of cleft lip with or without cleft palate associated with smoking (odds ratio [OR] = 1.79, 95% confidence interval [CI] = 1.07, 3.04) and an increased risk of cleft palate associated with alcohol consumption (OR = 2.28, 95% CI = 1.02, 5.09). The former risk increased with the number of cigarettes smoked. CONCLUSIONS: This study provides further evidence of the possible role of prevalent environmental exposures such as tobacco and alcohol in the etiology of oral clefts.     

Diet and oral premalignancy in female south Indian tobacco and betel chewers: a case-control study

The diets of 158 tobacco/betel quid-chewing women diagnosed with oral premalignant lesions and 155 quid-chewing but lesion-free controls, frequency matched for age, tobacco/betel habits, and socioeconomic status, were assessed using a food frequency survey. Index scores generated from the food frequency survey indicated that the mean levels of consumption for foods of animal origin (p < 0.001), total vegetables and fruit (p = 0.001), vegetables alone (p = 0.006), fruits alone (p = 0.006), and green leafy vegetables (p = 0.015) were significantly lower in cases than in controls. The mean index score for cobalamin (vitamin B12) was lower in cases with a borderline significance (p = 0.05), whereas the indexes for folate and carotene were not significantly different. The analysis of index scores estimating the number of 100-g servings per week of foods of animal origin [meat, eggs, milk, curd (yogurt), fish] consumed revealed that women who ate fewer servings were more likely to have premalignant lesions than those who ate more animal foods [odds ratio (OR) 3.38, 95% confidence interval (CI) 2.07-5.54, p = 0.001]. The risk for low consumption of vegetables was not as significant as that for foods of animal origin. However, those eating low levels of vegetables and low levels of foods of animal origin were at the greatest risk for lesions (OR 5.38, 95% CI 1.72-22.17, p < 0.05). In South Indian female tobacco/betel chewers, a diet deficient in foods of animal origin appears to be a more significant risk factor for oral premalignancy than is a diet deficient in fruits and vegetables.     

Recreational physical activity and risk of head and neck cancer: a pooled analysis within the international head and neck cancer epidemiology (INHANCE) Consortium

Increasing evidence suggests that physical activity could prevent cancer, but scanty data is available on head and neck cancer (HNC). The aim of our study is to clarify the effect of recreational physical activity (rPA) on HNC. We analyzed data from four case-control studies, including 2,289 HNC cases and 5,580 controls. rPA was classified as: none/low (reference group), moderate and high. We calculated summary Odds Ratios (ORs) by pooling study-specific ORs. Overall, moderate rPA was associated with 22% lower risk of HNC compared to those with none or very low rPA levels [OR?=?0.78, 95% Confidence Interval (95% CI): 0.66, 0.91]. Moderate rPA is associated with reduced risk of oral (OR?=?0.74, 95% CI: 0.56, 0.97) and pharyngeal cancer (OR?=?0.67, 95% CI: 0.53, 0.85), as well as high rPA levels (OR?=?0.53, 95% CI: 0.32, 0.88 for oral cavity, OR?=?0.58, 95% CI: 0.38, 0.89 for pharynx). High rPA levels, however, is associated with higher risk of laryngeal cancer (OR?=?1.73, 95% CI: 1.04, 2.88). Stratified analyses showed that such inverse association between moderate rPA and HNC was more evident among males (OR?=?0.75, 95% CI: 0.62, 0.90), subjects ≥45?years (OR?=?0.78, 95% CI: 0.66, 0.93), and ever smokers and ever drinkers (OR?=?0.72, 95% CI: 0.59, 0.88). High rPA significantly reduces HNC risk among subject ≥45?years (OR?=?0.66, 95% CI: 0.48, 0.91). Promoting rPA might be inversely associated with HNC.     

Risk factors for laryngeal cancer in Montenegro

Laryngeal cancer is the most common head and neck cancer. There might be many risk factors for laryngeal cancer. Smoking, especially cigarette smoking and alcohol are indisputable risk factors. The authors of this paper assessed the presumed risk factors in order to identify possible aetiological agents of the disease.A hospital-based case-control study was conducted. The study group consisted of 108 histologically verified laryngeal cancer patients and 108 hospital controls matched by sex, age (+/-3 years) and place of residence. Laryngeal cancer patients and controls were interviewed during their hospital stay using a structured questionnaire. According to multiple logistic regression analysis six variables were independently related to laryngeal cancer: hard liquor consumption (Odd Ratio/OR/=2.93, Confidence Interval/CI/95% = 1.17 to 7.31), consumption more than 2 alcoholic drinks per day (OR=4.96, CI 95% = 2.04 to 12.04), cigarette smoking for more than 40 years (OR=4.32, CI 95% = 1.69 to 11.06), smoking more than 30 cigarettes per day (OR=4.24, CI 95% = 1.75 to 10.27), coffee consumption more than 5 cups per day (OR=4.52, CI 95% = 1.01 to 20.12) and carbonated beverage consumption (OR=0.38, CI 95%=0.16 to 0.92). The great majority of laryngeal cancers could be prevented by eliminating tobacco smoking and alcohol consumption.     

Cruciferous vegetables, mushrooms, and gastrointestinal cancer risks in a multicenter, hospital-based case-control study in Japan

We assessed the possible association of gastrointestinal cancers with cruciferous vegetables and mushrooms in a multicenter, hospital-based case-control study in an agricultural area of Japan. One hundred forty-nine cases and 287 controls for stomach cancer and 115 cases and 230 controls for colorectal cancer were matched by age, sex, and residential area. In stomach cancer, the protective effect of vegetables (consumption of total vegetable) was obscure, but it became clearer when we examined specific kinds of vegetables. Marginal associations were observed in the group of the highest consumption of Chinese cabbage (odds ratio [OR] = 0.61; 95% confidence interval [CI] = 0.35-1.07), broccoli (OR = 0.60; 95% CI = 0.34-1.08), Hypsizigus marmoreus (Bunashimeji) (OR = 0.57; 95% CI = 0.31-1.04) and Pholita nameko (Nameko) (OR = 0.56; 95% CI = 0.30-1.06). In colorectal cancer, we observed decreased risks from the highest tertile of total vegetables (OR = 0.22; 95% CI = 0.08-0.66) and low-carotene-containing vegetables (OR = 0.28; 95% CI = 0.08-0.77), and inverse associations were observed in the group of the highest consumption of broccoli (OR = 0.18; 95% CI = 0.06-0.58). Although the sample size was limited, subgroup analyses showed that the associations differed with the histopathological subtype. These findings suggest that cruciferous vegetables decrease the risk of both stomach and colorectal cancer, and that mushrooms are associated with a decreased risk of stomach cancer.     

A prospective study of green tea consumption and oral cancer incidence in Japan

PURPOSE: To examine the relation of green tea consumption with oral carcinogenesis, we prospectively analyzed data from a nationwide large-scale cohort study in Japan. METHODS: A total of 20,550 men and 29,671 women aged 40-79 years, without any history of oral and pharyngeal cancer at baseline survey, were included in the present study. During a mean follow-up period of 10.3 years, 37 oral cancer cases were identified. The Cox proportional hazard model was used to estimate the hazard ratio (HR) and 95% confidence interval (95% CI) for oral cancer according to green tea consumption by sex, while adjusting for age, smoking, alcohol drinking, and other dietary factors. RESULTS: For women, the HRs of oral cancer for green tea consumption of 1-2, 3-4, and 5 or more cups per day were 0.51 (95% CI: 0.10-2.68), 0.60 (95% CI: 0.17-2.10), and 0.31 (95% CI: 0.09-1.07), respectively, compared with those who drank less than one cup per day (p for trend, 0.08). For men, no such trends were observed. CONCLUSIONS: Our findings did not suggest a prominent inverse association of green tea consumption with oral cancer, although there was a tendency for a reduced risk in women.     

Fruit and Vegetable Consumption and Lung Cancer Risk: A Case-Control Study in Galicia,Spain

Lung cancer has multiple risk factors and tobacco is the main one. Diet plays a role, but no clear effect has been consistently observed for different fruit and vegetable consumption. We aim to assess the association between fruit and vegetable consumption and lung cancer risk through a hospital-based case-control study in Spanish population. We recruited incident lung cancer cases in 2 Spanish hospitals from 2004 to 2008. Controls were individuals attending hospital for trivial surgery. Cases and controls were older than 30 and did not have a neoplasic history. We collected information on lifestyle with special emphases on tobacco and dietary habits. We included 371 cases and 496 controls. We found no protective effect for overall fruit consumption. For green leafy vegetables, the odds ratio (OR) was 0.92 [95% confidence interval (CI) = 0.32–2.69), and for other vegetables the OR was 0.77 (95% CI = 0.40–1.48) for the categories compared. We observed a reduced risk for broccoli and pumpkin intake. Although fruit consumption does not seem to be associated with a lower lung cancer risk, only the frequent consumption of specific green leafy vegetables and other vegetables might be associated with a reduced risk of lung cancer.     

Diet and prostatic cancer: a case-control study in northern Italy.

The relationship between intake of various indicator foods and beverages and risk of prostatic cancer was assessed in 271 cases of prostatic cancer and 685 hospital controls recruited in two areas of northern Italy, the province of Pordenone and the greater Milan area. Increased risks were found for more frequent intake of meat [odds ratio (OR) in the highest vs. lowest consumption tertile = 1.4, 95% confidence interval (CI) 1.0-2.0], milk (OR = 1.6, 95% CI 1.1-2.4), fresh fruit (OR = 1.4, 95% CI 1.0-2.1), and vegetables (OR = 1.4, 95% CI 0.9-2.2). After allowance for the reciprocal confounding effect of various dietary habits, only frequent intake of milk seemed to be a significant independent indicator of prostatic cancer risk. There was also a clue that the unfavorable influence of frequent intake of a few food items (i.e. meat, fish, liver, ham and salami, milk and butter, and retinol) may be greater or restricted to older individuals (i.e., > or = 70 yrs of age). In conclusion, the present study confirms the presence of a moderate adverse effect of high intake of foods of animal origin, chiefly milk, while it suggests that a diet rich in fresh fruit and vegetables does not convey a protection.     

Association between fruit and vegetable consumption and oral cancer: a meta-analysis of observational studies

BACKGROUND: Oral cancer ranks as the seventh most common form of cancer worldwide. Recent reports have examined the effect of fruit and vegetable intake on the risk of oral cancer, but results are controversial. OBJECTIVE: A meta-analysis was performed to arrive at quantitative conclusions about the contribution of fruit and vegetable intakes to the occurrence of oral cancer. DESIGN: A comprehensive, systematic bibliographic search of medical literature published up to September 2005 was conducted to identify relevant studies. Separate meta-analyses were conducted for fruit and vegetable consumption. The effect of portion or daily intake of fruit or vegetables on the risk of oral cancer was calculated. A multivariate meta-regression analysis was performed to explore heterogeneity. This multivariate meta-regression analysis examined the effect of quality score, the type of cancers included, citrus fruit and green vegetable consumption, and the time interval for dietary recall of the studies on the role of fruit or vegetable consumption in the risk of oral cancer. The presence of publication bias was assessed with a funnel plot for asymmetry. RESULTS: Sixteen studies (15 case-control studies and 1 cohort study) met the inclusion criteria and were included in the meta-analysis. The combined adjusted odds ratio (OR) estimates showed that each portion of fruit consumed per day significantly reduced the risk of oral cancer by 49% (OR: 0.51; 95% CI: 0.40, 0.65). For vegetable consumption, the meta-analysis showed a significant reduction in the overall risk of oral cancer of 50% (OR: 0.50; 95% CI: 0.38, 0.65). The multivariate meta-regression showed that the lower risk of oral cancer associated with fruit consumption was significantly influenced by the type of fruit consumed and by the time interval of dietary recall. CONCLUSION: The consumption of fruit and vegetables is associated with a reduced risk of oral cancer.     

Impact of consumption of vegetable, fruit, grain, and high glycemic index foods on aggressive prostate cancer risk

Prostate cancer is a common but complex disease, and distinguishing modifiable risk factors such as diet for more aggressive disease is extremely important. Previous work has detected intriguing associations between vegetable, fruit, and grains and more aggressive prostate cancer, although these remain somewhat unclear. Here we further investigate such potential relationships with a case-control study of 982 men (470 more aggressive prostate cancer cases and 512 control subjects). Comparing the highest to lowest quartiles of intake, we found that increasing intakes of leafy vegetables were inversely associated with risk of aggressive prostate cancer [adjusted odds ratio (OR) = 0.66, 95% CI: 0.46, 0.96; P trend = 0.02], as was higher consumption of high carotenoid vegetables (OR = 0.71, 95% CI: 0.48, 1.04; P trend = 0.04). Conversely, increased consumption of high glycemic index foods were positively associated with risk of aggressive disease (OR = 1.64, 95% CI: 1.05, 2.57; P trend = 0.02). These results were driven by a number of specific foods within the food groups. Our findings support the hypothesis that diets high in vegetables and low in high glycemic index foods decrease risk of aggressive prostate cancer.