Well-done, grilled red meat increases the risk of colorectal adenomas.

Red meat or meat-cooking methods such as frying and doneness level have been associated with an increased risk of colorectal and other cancers. It is unclear whether it is red meat intake or the way it is cooked that is involved in the etiology of colorectal cancer. To address this issue, we developed an extensive food frequency questionnaire module that collects information on meat-cooking techniques as well as the level of doneness for individual meat items and used it in a study of colorectal adenomas, known precursors of colorectal cancer. A case-control study of colorectal adenomas was conducted at the National Naval Medical Center (Bethesda, MD) between April 1994 and September 1996. All cases (n = 146) were diagnosed with colorectal adenomas at sigmoidoscopy or colonoscopy and histologically confirmed. Controls (n = 228) were screened with sigmoidoscopy and found not to have colorectal adenomas. The subjects completed a food frequency questionnaire and answered detailed questions on meat-cooking practices. We used frequency and portion size to estimate grams of meat consumed per day for total meat as well as for meat subgroups defined by cooking methods and doneness levels. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using logistic regression, adjusted for age, gender, total caloric intake, reason for screening (routine or other), and several established risk factors for colorectal adenomas or cancer, including the use of nonsteroidal anti-inflammatory drugs, physical activity, and pack-years of cigarette smoking. There was an increased risk of 11% per 10 g/day (or 2.5 oz/week) of reported red meat consumption (OR, 1.11; CI, 1.03-1.19). The increased risk was mainly associated with well-done/very well-done red meat, with an excess risk of 29% per 10 g/day (OR, 1.29; CI, 1.08-1.54) versus an excess of 10% per 10 g/day (OR, 1.10; CI, 0.96-1.26) for consumption of rare/medium red meat. High-temperature cooking methods were also associated with increased risk; 26% per 10 g/day (OR, 1.26; CI, 1.06-1.50) of grilled red meat and 15% per 10 g/day (OR, 1.15; CI, 0.97-1.36) of pan-fried red meat consumption. There was an increased risk of colorectal adenomas associated with higher intake of red meat, most of which was due to the subgroup of red meat that was cooked until well done/very well done and/or by high-temperature cooking techniques, such as grilling. These results are consistent with the hypothesis that carcinogenic compounds formed by high-temperature cooking techniques, such as heterocyclic amines and polycyclic aromatic hydrocarbons, may contribute to the risk of developing colorectal tumors.     

Meat intake and risk of non-Hodgkin lymphoma

We conducted a population-based, case-control study to test the hypothesis that consumption of meat and meat-related mutagens increases the risk of non-Hodgkin lymphoma (NHL), and whether the associations are modified by N-acetyltransferase (NAT) 1 and 2. Participants (336 cases and 460 controls) completed a 117-item food frequency questionnaire. The risk of NHL was associated with a higher intake of red meat (OR?=?1.5; CI, 1.1-2.2), total fat (OR?=?1.4; CI, 1.0-2.1), and oleic acid (OR?=?1.5; CI, 1.0-2.2). NHL risk was also associated with a higher intake of very well-done pork (OR?=?2.5; 95?% CI, 1.4-4.3) and the meat-related mutagen MeIQx (OR?=?1.6; 95?% CI, 1.1-2.3). Analyses of the major NHL histologic subtypes showed a positive association between diffuse large B cell lymphoma (DLBCL) and higher intake of red meat (OR?=?2.1; 95?% CI, 1.1-3.9) and the association was largely due to meat-related mutagens as a positive association was observed for higher intakes of both MeIQx (OR?=?2.4; 95?% CI, 1.2-4.6) and DiMeIQx (OR?=?1.9; 95?% CI, 1.0-3.5). Although the OR for follicular lymphoma (FL) was also increased with a higher red meat intake (OR?=?1.9; 95?% CI, 1.1-3.3), the association appeared to be due to increased oleic acid (OR?=?1.7; 95?% CI: 0.9-3.1). We found no evidence that polymorphisms in NAT1 or NAT2 modify the association between NHL and meat-related mutagens. Our results provide further evidence that red meat consumption is associated with an increase in NHL risk, and new evidence that the specific components of meat, namely fat and meat-related mutagens, may be impacting NHL subtype risk differently.     

Calcium, dietary, and lifestyle factors in the prevention of colorectal adenomas

BACKGROUND: Many studies have suggested a role for calcium in reducing the risk of colorectal adenomas and cancer but its effectiveness may be dependent on interactions with other dietary and/or lifestyle factors. We examined the association between calcium and prevalence of adenomas and assessed whether the association was stronger in biologically plausible subgroups. METHODS: Cross-sectional data from 222 cases and 479 adenoma-free controls who underwent colonoscopies and completed food frequency and lifestyle questionnaires were used in the analyses. Multivariable logistic regression was used to estimate the association between calcium and prevalence of adenomas. Stratified analyses and the likelihood ratio test were used to examine effect modification by various demographic, lifestyle, and behavioral factors. RESULTS: Overall, little association was observed comparing total calcium intake of > or = 900 mg/day to < 500 mg/day (adjusted odds ratio [OR] = 0.85, 95% confidence interval [CI]: 0.53-1.37). However, stronger associations were observed in patients with lower fat intake and in those who regularly (> or = 15 times/month) took nonsteroidal antiinflammatory drugs (NSAIDs). Specifically, total calcium intake of > or = 900 mg/day was associated with a lower prevalence of adenomas among patients with lower fat intake (OR = 0.47, 95% CI: 0.25-0.91) but not among those with higher fat intake (OR = 1.20, 95% CI: 0.61-2.35; P-value for interaction = .01). For NSAIDs, the associations were OR = 0.37 (95% CI: 0.16-0.86) for regular NSAID users and OR = 1.27 (95% CI: 0.73-2.22) with infrequent or nonuse of NSAIDs, respectively (P = .06). CONCLUSIONS: The data suggest that a lower-fat diet and regular NSAID use may enhance calcium's effectiveness as a colorectal cancer preventive agent.     

Dietary fat and meat intakes and risk of reflux esophagitis, Barrett's esophagus and esophageal adenocarcinoma

The aim of our study was to investigate whether dietary fat and meat intakes are associated with reflux esophagitis (RE), Barrett's esophagus (BE) and esophageal adenocarcinoma (EAC). In this all-Ireland case-control study, dietary intake data were collected using a food frequency questionnaire in 219 RE patients, 220 BE patients, 224 EAC patients and 256 frequency-matched controls between 2002 and 2005. Unconditional multiple logistic regression analysis was used to examine the association between dietary variables and disease risk using quartiles of intake, to attain odds ratios (ORs) and 95% confidence intervals (95% CIs), while adjusting for potential confounders. Patients in the highest quartile of total fat intake had a higher risk of RE (OR = 3.54; 95% CI = 1.32-9.46) and EAC (OR = 5.44; 95% CI = 2.08-14.27). A higher risk of RE and EAC was also reported for patients in the highest quartile of saturated fat intake (OR = 2.79; 95% CI = 1.11-7.04; OR = 2.41; 95% CI = 1.14-5.08, respectively) and monounsaturated fat intake (OR = 2.63; 95% CI = 1.01-6.86; OR = 5.35; 95% CI = 2.14-13.34, respectively). Patients in the highest quartile of fresh red meat intake had a higher risk of EAC (OR = 3.15; 95% CI = 1.38-7.20). Patients in the highest category of processed meat intake had a higher risk of RE (OR = 4.67; 95% CI = 1.71-12.74). No consistent associations were seen for BE with either fat or meat intakes. Further studies investigating the association between dietary fat and food sources of fat are needed to confirm these results.     

Meat, meat cooking methods and preservation, and risk for colorectal adenoma

Cooking meat at high temperatures produces heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs). Processed meats contain N-nitroso compounds. Meat intake may increase cancer risk as HCAs, PAHs, and N-nitroso compounds are carcinogenic in animal models. We investigated meat, processed meat, HCAs, and the PAH benzo(a)pyrene and the risk of colorectal adenoma in 3,696 left-sided (descending and sigmoid colon and rectum) adenoma cases and 34,817 endoscopy-negative controls. Dietary intake was assessed using a 137-item food frequency questionnaire, with additional questions on meats and meat cooking practices. The questionnaire was linked to a previously developed database to determine exposure to HCAs and PAHs. Intake of red meat, with known doneness/cooking methods, was associated with an increased risk of adenoma in the descending and sigmoid colon [odds ratio (OR), 1.26; 95% confidence interval (95% CI), 1.05-1.50 comparing extreme quintiles of intake] but not rectal adenoma. Well-done red meat was associated with increased risk of colorectal adenoma (OR, 1.21; 95% CI, 1.06-1.37). Increased risks for adenoma of the descending colon and sigmoid colon were observed for the two HCAs: 2-amino-3,8-dimethylimidazo[4,5]quinoxaline and 2-amino-1-methyl-6-phenylimidazo[4,5]pyridine (OR, 1.18; 95% CI, 1.01-1.38 and OR, 1.17, 95% CI, 1.01-1.35, respectively) as well as benzo(a)pyrene (OR, 1.18; 95% CI, 1.02-1.35). Greater intake of bacon and sausage was associated with increased colorectal adenoma risk (OR, 1.14; 95% CI, 1.00-1.30); however, total intake of processed meat was not (OR, 1.04; 95% CI, 0.90-1.19). Our study of screening-detected colorectal adenomas shows that red meat and meat cooked at high temperatures are associated with an increased risk of colorectal adenoma.     

Food Intake and Colorectal Adenomas: A Case-Control Study in Malaysia

It is well established that almost all colorectal cancers arise from benign, neoplastic adenomatous polyps. Inprevious studies, intake of fruits, vegetables and legumes were found to decrease the risk for colorectal adenomas(CRA) and colorectal cancer. This case-control study aimed to evaluate the role of a variety of foods in contributingto the risk of CRA in Malaysian subjects. One hundred and eighteen subjects were recruited into case (n=59)and control (n=59) groups at Hospital Kuala Lumpur (HKL). A pre-tested quantitative food frequencyquestionnaire (FFQ) was used to record the types of food items and frequency consumed. Logistic regressionwas used to determine the crude and adjusted odds ratios of the independent variables. Soy bean and soyproducts were associated with a reduced risk for CRA (OR = 0.38, 95% CI = 0.15-0.98), while tubers wereassociated with increase in risk four-fold (OR = 4.14, 95% CI = 1.60-10.70) and red meat intake was found toincrease the risk two and a half-fold (OR = 2.51, 95% CI = 1.02-6.28). Higher servings of fruits and vegetableswere found to significantly decrease the risk (OR fruits= 0.47, 95% CI = 0.30-0.74; OR vegetables = 0.49, 95%= 0.29-0.80). In conclusion, our data support protective roles for soy, fruits and vegetables in the aetiology ofcolorectal adenomas and increase in risk in those with high intakes of red meat and tubers. Food intake of anindividual may have an influence on one’s risk for developing CRA. This finding warrants further investigationbefore the protective effect of these food items is to be accepted. New studies should explore the possibility ofthese associations among individuals in the general population especially with regard to different ethnic orother groups in Malaysia with low fruit and vegetable consumption.     

Fat intake and its relationship with pre- and post-menopausal breast cancer risk: a case-control study in Malaysia

Background: Fat intake has been shown to play a role in the etiology of breast cancer, but the findings have been inconsistent. Objective: To assess the association of premenopausal and postmenopausal breast cancer risk with fat and fat subtypes intake. Methodology: This is a population based case-control study conducted in Kuala Lumpur, Malaysia from January 2006 to December 2007. Food intake pattern was collected from 382 breast cancer patients and 382 control group via an interviewer-administered food frequency questionnaire. Logistic regression was used to compute odds ratios (OR) with 95% confidence intervals (CI) and a broad range of potential confounders was included in analysis. Results: This study showed that both premenopausal and postmenopausal breast cancer risk did not increase significantly with greater intake of total fat [quartile (Q) 4 versus Q1 OR=0.76, 95% CI, 0.23-2.45 and OR=1.36, 95% CI, 0.30-3.12], saturated fat (ORQ4 to Q1=1.43, 95% CI, 0.51-3.98 and ORQ4 to Q1=1.75, 95% CI, 0.62-3.40), monounsaturated fat (ORQ4 to Q1=0.96, 95% CI, 0.34-1.72 and ORQ4 to Q1=1.74, 95% CI, 0.22-2.79), polyunsaturated fat (ORQ4 to Q1=0.64, 95% CI, 0.23-1.73 and ORQ4 to Q1=0.74, 95% CI, 0.39-1.81), n-3 polyunsaturated fat (ORQ4 to Q1=1.10, 95% CI, 0.49-2.48 and ORQ4 to Q1=0.78, 95% CI, 0.28-2.18), n-6 polyunsaturated fat (ORQ4 to Q1=0.67, 95% CI, 0.24-1.84 and ORQ4 to Q1=0.71, 95% CI, 0.29-1.04) or energy intake (ORQ4 to Q1=1.52, 95% CI, 0.68-3.38 and ORQ4 to Q1=2.21, 95% CI, 0.93-3.36). Conclusion: Total fat and fat subtypes were not associated with pre- and postmenopausal breast cancer risk after controlling for age, other breast cancer risk factors and energy intake. Despite the lack of association, the effects of total fat and fat subtypes intake during premenopausal years towards postmenopausal breast cancer risk still warrant investigation.     

Risk of Colorectal Adenomas in Relation to Meat Consumption, Meat Preparation, and Genetic Susceptibility in a Dutch Population

OBJECTIVE: We studied the association between meat consumption and colorectal adenomas, and potential influence of genetic susceptibility to heterocyclic aromatic amines (HCAs) formed during meat cooking at high temperatures. METHODS: We studied HCA concentration in relation to preparation habits among 63 volunteers. Associations of meat consumption, meat preparation habits, and genetic susceptibility with colorectal adenoma risk were investigated among 431 adenoma cases and 433 polyp-free controls recruited at endoscopy. Participants completed a meat consumption and preparation questionnaire and provided blood for DNA isolation. Polymorphisms of N-acetyltransferases (NAT) 1 and 2, sulfotransferase (SULT) 1A1, and glutathione-S-transferases (GST) M1 and T1 were determined. RESULTS: HCAs were present in habitually prepared meat, although meat consumption (7 versus < 5x/week) did not increase the risk of colorectal adenomas (odds ratio (OR) 1.2, 95% confidence interval (CI) 0.8-1.9). Also, presumed unfavorable preparation habits (e.g., use of lid, preference for darkly browned meat) did not increase adenoma risk (OR 0.8 and 0.9, respectively). Only the combination of NAT2 slow acetylation and frequent meat consumption (> 5x/week) slightly increased adenoma risk (OR 1.6, 95% CI 1.1-2.3). CONCLUSIONS: In this Dutch population, unfavorable meat consumption and preparation habits did not increase colorectal adenoma risk, and these associations were not influenced by relevant genetic polymorphisms.     

Fried, well-done red meat and riskof lung cancer in women (United States)

Objective: Some epidemiological studies suggest that diets high in fat, saturated fat, or cholesterol are associated with increased risk of lung cancer. Since meat consumption is correlated with the intake of saturated fat and cholesterol, we investigated the role of meat intake and cooking practices in relation to lung cancer risk.Methods: A population-based case-control study of both non-smoking and smoking women was conducted in Missouri. A 100-item food frequency questionnaire (FFQ) with detailed questions on meat consumption was completed by 593 cases and 623 frequency matched controls. We estimated quantity of meat eaten (grams/day) according to cooking method, and doneness level. Odds ratios (ORs) and 95% confidence intervals (C.I.s) were calculated using logistic regression. Multivariate models included age, packyears of smoking, body mass index (BMI, kg/m2), education, and intake of calories, fat, fruit/fruit juices, and vegetables.Results: When comparing 90th and 10th percentiles, lung cancer risk increased for total meat consumption (OR=1.6, C.I. 1.1-2.4), red meat (OR=1.8, C.I., 1.2-2.7), well-done red meat (OR=1.5, C.I.s, 1.1-2.1) and fried red meat (OR=1.5, C.I., 1.1-2.0). The odds ratios for 5th vs. 1st quintiles using the categorical variable for well-done red meat and fried red meat were essentially the same as reported above; however, the increase in risk was associated mainly with the 5th quintile. The ORs for a 10-gram increase in consumption were, 1.04 for total meat, 1.06 for red meat, 1.08 for well done red meat, and 1.09 for fried red meat.Conclusions: Consumption of red meat, especially fried and/or well-done red meat, was associated with increased risk of lung cancer.     

Meat intake, preparation methods, mutagens and colorectal adenoma recurrence

Red meat intake has been shown to be associated with higher risk of colorectal cancer. Though the exact mechanisms responsible for this association remain unknown, several tumorigenic properties of meat have been proposed. One well-supported biologic mechanism is elevated exposure to the genotoxic formation of heterocyclic amines (HCAs), which occur when meat is cooked at high temperatures for a long period of time. We prospectively assessed the relation between type of meat, meat preparation method, doneness, a metric of HCAs and other mutagens and colorectal adenoma recurrence among 869 participants in a chemoprevention trial of ursodeoxycholic acid. Unconditional logistic regression analyses were used to estimate odds ratios (ORs) and associated 95% confidence intervals (CIs). Most meat variables assessed were positively but weakly associated with recurrence of any adenoma. In contrast, recurrence of advanced or multiple adenomas was more strongly associated with a number of the meat exposure variables evaluated. For recurrence of advanced lesions, significant associations were detected among individuals in the highest when compared with the lowest tertile of intake for pan-fried red meat (OR = 1.85; 95% CI = 1.10-3.13) and well/very well done red meat (OR = 1.71; 95% CI = 1.02-2.86). Significant positive associations were shown for recurrence of multiple adenomas and the following variables: processed meat (OR = 1.83; 95% CI = 1.10-3.04), pan-fried red meat (OR = 1.63; 95% CI = 1.01-2.61), well/very well done red meat (OR = 1.68; 95% CI = 1.03-2.74), 2-amino-3,4,8-trimethylimidazo[4,5,-f]quinoxaline (OR = 1.74; 95% CI = 1.07-2.82) and 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (OR = 1.68; 95% CI = 1.03-2.75). Our results support a meat mutagen exposure hypothesis as a potential mechanism for recurrence of clinically significant adenomatous polyps.     

Meat intake and risk of gastric cancer in the Stomach cancer Pooling (StoP) project

The consumption of processed meat has been associated with noncardia gastric cancer, but evidence regarding a possible role of red meat is more limited. Our study aims to quantify the association between meat consumption, namely white, red and processed meat, and the risk of gastric cancer, through individual participant data meta-analysis of studies participating in the “Stomach cancer Pooling (StoP) Project”. Data from 22 studies, including 11,443 cases and 28,029 controls, were used. Study-specific odds ratios (ORs) were pooled through a two-stage approach based on random-effects models. An exposure-response relationship was modeled, using one and two-order fractional polynomials, to evaluate the possible nonlinear association between meat intake and gastric cancer. An increased risk of gastric cancer was observed for the consumption of all types of meat (highest vs. lowest tertile), which was statistically significant for red (OR: 1.24; 95% CI: 1.00–1.53), processed (OR: 1.23; 95% CI: 1.06–1.43) and total meat (OR: 1.30; 95% CI: 1.09–1.55). Exposure-response analyses showed an increasing risk of gastric cancer with increasing consumption of both processed and red meat, with the highest OR being observed for an intake of 150 g/day of red meat (OR: 1.85; 95% CI: 1.56–2.20). This work provides robust evidence on the relation between the consumption of different types of meat and gastric cancer. Adherence to dietary recommendations to reduce meat consumption may contribute to a reduction in the burden of gastric cancer.     

Food groups and risk of squamous cell carcinoma of the oesophagus: a case-control study in Uruguay

In the time period January 1998-December 2000, a case-control study on squamous cell cancer of the oesophagus was conducted in Montevideo, Uruguay. The main objective of the study was to estimate the odds ratios (ORs) associated with main food groups. For this purpose, 166 patients afflicted with squamous cell oesophageal cancer and 664 hospitalised controls were frequency matched on age and sex. Both series of patients were administered with a structured questionnaire. Aside from queries related with tobacco smoking, alcohol drinking and maté drinking, patients were interviewed with a food-frequency questionnaire (FFQ) on 64 items, representative of the usual Uruguayan diet. Red meat, salted meat and boiled meat displayed strong direct associations (OR for red meat 2.4, 95% CI 1.4-4.2). On the other hand, fish and total white meat showed moderate protective effect (OR for total white meat 0.5, 95% CI 0.3-0.9). Total fruit intake displayed a strong inverse association (OR 0.2, 95% CI 0.1-0.4), whereas total vegetable consumption presented a weak inverse association (OR for total vegetable intake 0.7, 95% CI 0.4-1.2). These results suggest that vegetables, mainly cooked vegetables, are rich in thermolabile protective substances. On the other hand, boiled (stewed) meat, which is ingested at high temperature could be, like maté, a risk factor for squamous cell cancer of the oesophagus.     

Diet, lifestyle and risk of K-ras mutation-positive and -negative colorectal adenomas

K-ras mutation-positive (K-ras+) and -negative (K-ras-) colorectal adenomas may differ clinically and pathologically. As environmental compounds may cause mutations in the growth-related K-ras oncogene or affect clonal selection depending on mutational status, we evaluated whether the aetiology of K-ras+ and K-ras- adenomas differs. K-ras mutations in codons 12 and 13 were assessed in colorectal adenoma tissue (K-ras+: n = 81, K-ras-: n = 453). Dietary and lifestyle data were collected through questionnaires that were also administered to 709 polyp-free controls. Multiple logistic regression analyses showed that intake of vitamin B2 and monounsaturated fat were differently associated with risk of K-ras+ and K-ras- adenomas; vitamin B2 was inversely associated with K-ras- (highest vs. lowest tertile: odds ratio (OR) = 0.70, 95% confidence interval (CI) = 0.50-0.97, p trend = 0.020), but not with K-ras+ adenomas, and a positive association with monounsaturated fat was confined to K-ras- adenomas (OR = 1.57, 95% CI = 1.06-2.34, p trend = 0.029). Besides, potential, not statistically significant, differences in risk arose because red meat was distinctly positively associated with K-ras+ adenomas (OR = 1.70, 95% CI = 0.94-3.09, p trend = 0.061); total dietary and polyunsaturated fat tended to be inversely associated with risk of K-ras+ but not of K-ras- adenomas; inverse associations with dairy products, calcium, protein and tea were confined to K-ras- adenomas, and smoking was more markedly positively associated with K-ras- adenomas. No differences in risk of K-ras+ and K-ras- adenomas could be detected for other factors. In conclusion, dietary and lifestyle factors may influence risk of K-ras+ and K-ras- adenomas differently. However, epidemiological literature on diet, lifestyle and colorectal K-ras mutations is inconsistent.     

Dietary factors and truncating APC mutations in sporadic colorectal adenomas

Inactivating mutations in APC are thought to be early, initiating events in colorectal carcinogenesis. To gain insight into the relationship between diet and inactivating APC mutations, we evaluated associations between dietary factors and the occurrence of these mutations in a Dutch case-control study of sporadic colorectal adenomas (278 cases; 414 polyp-free controls). Direct-sequencing was used to screen adenomas for mutations in the mutation cluster region of APC; truncating mutations were detected in 161 (58%) of the adenomas. Red meat consumption was significantly differently related to polyps with truncating APC mutation (APC(+) polyps) compared to polyps without truncating APC mutation (APC(-) polyps) (highest vs. lowest tertile, odds ratio [OR] = 0.5, 95% confidence interval [CI] = 0.3-1.0). High intake of red meat and fat seemed to increase the risk of APC(-) polyps only (APC(+) vs. controls: red meat, OR = 1.0, 95% CI = 0.6-1.6; fat, OR = 1.1, 95% CI = 0.6-1.9; APC(-) vs. controls: red meat, OR = 1.8, 95% CI = 1.0-3.1; fat, OR = 1.9, 95% CI = 1.0-3.7). Intake of carbohydrates was inversely associated with both polyp groups, most noticeably with APC(-) polyps. Most other evaluated dietary factors were not distinctively associated with a specific APC status. None of the dietary factors was specifically associated with a particular type of truncating APC mutation. Our data suggest that red meat and fat may increase the risk of APC(-) polyps in particular, whereas carbohydrates may especially decrease the risk of APC(-) polyps. However, most examined dietary factors do not appear to be specifically associated with the occurrence of truncating APC mutations in colorectal adenomas but seem to affect both pathways equally.     

Relationship of diet to risk of colorectal adenoma in men.

BACKGROUND: Rates of colorectal cancer in various countries are strongly correlated with per-capita consumption of red meat and animal fat and inversely associated with fiber consumption. There have been few studies, however, of dietary risk factors for colorectal adenomas, which are precursors of cancer. PURPOSE: Our purpose was to determine prospectively the relationship between dietary factors and risk of colorectal adenomas. METHODS: Using data from the Health Professionals Follow-up Study, we documented 170 cases of adenomas of the left colon or rectum in 7284 male health professionals who completed a food-frequency questionnaire in 1986 and who had a colonoscopy or sigmoidoscopy between 1986 and 1988. Relative risk (RR) of adenoma was determined according to quintiles of nutrient intakes. RESULTS: After adjustment for total energy intake, saturated fat was positively associated with risk of colorectal adenoma (P for trend = .006); RR for the highest versus the lowest quintile of intake was 2.0 (95% confidence interval [CI] = 1.2-3.2). Dietary fiber was inversely associated with risk of adenoma (P for trend less than .0001); RR for men in the highest versus the lowest quintile was 0.36 (95% CI = 0.22-0.60). All sources of fiber (vegetables, fruits, and grains) were associated with decreased risk of adenoma. For subjects on a high-saturated fat, low-fiber diet, the RR was 3.7 (95% CI = 1.5-8.8) compared with those on a low-saturated fat, high-fiber diet. The ratio of the intake of red meat to the intake of chicken and fish was positively associated with risk of adenoma (P for trend = .02). CONCLUSIONS: These prospective data provide evidence for the hypothesis that a diet high in saturated fat and low in fiber increases the risk of colorectal adenoma. They also support existing recommendations to substitute chicken and fish for red meat in the diet and to increase intake of vegetables, fruits, and grains to reduce risk of colorectal cancer.     

Meat and meat-mutagen intake, doneness preference and the risk of colorectal polyps: the Tennessee Colorectal Polyp Study

Although meat intake has been fairly consistently linked to the risk of colorectal cancer, only a few studies have evaluated meat intake by doneness level and the heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs) produced by high temperature cooking of meat in relation to colorectal adenomatous and hyperplastic polyps. We evaluated these associations in a large colonoscopy-based case-control study. Included in this study were participants with adenomatous polyp only (n = 573), hyperplastic polyp only (n = 256), or both adenomatous and hyperplastic polyps (n = 199), and 1,544 polyp-free controls. In addition to information related to demographic and other lifestyle factors, meat intake by cooking method and doneness preference were obtained through telephone interviews. Polytomous logistic regression models were used to estimate odds ratios (OR) and 95% confidence intervals for the association between exposures and colorectal polyp risks. Presence of hyperplastic polyp was found to be positively associated with high consumption of total meat (p(trend) = 0.076) or red meat (p(trend) = 0.060), with an approximate 50-60% elevated risk observed in the highest vs. the lowest intake group. High intake of 2-amino-I-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and 2-amino-3,4,8-trimethylimidazo [4,5]quinoxaline (DiMeIQx) were associated with increased risk for hyperplastic polyp (p(trend) = 0.036 and 0.038, respectively). With a possible exception of the intake of total well-done meats (p(trend) = 0.055) or well-done red meats (p(trend) = 0.074) with the risk of large adenomas, no other positive association was found specifically for the risk of adenomas with any of the exposure variables aforementioned. This study provides additional support for a positive association of high intake of red meat with colorectal adenomas, and suggests that high intake of meats and meat carcinogens may also be associated with hyperplastic polyps.     

p53 over-expression and p53 mutations in colon carcinomas: relation to dietary risk factors.

Epidemiological studies have suggested that dietary factors may differently affect p53-dependent and p53-independent pathways to colon cancer. Results of such studies may depend on the method used to assess p53 status. This case-control study of 185 colon-cancer cases and 259 controls examines this relation, using both immunohistochemistry and SSCP(exons 5-8)/sequencing to detect p53 abnormalities. Of 185 carcinomas analyzed using immunohistochemistry, 81 (44%) were categorized as p53 over-expression. p53 mutations were detected in 59 tumors (32%). A slight increase in risk observed for intake of saturated fat was largely due to an increased risk in cases without p53 over-expression (OR per 16.1 g/day, 1.46; 95% CI, 1.08-1.97), and no association in cases with p53 over-expression (OR, 1.07, 95% CI, 0.78-1.47). However, findings were less pronounced when cases were classified by mutation analysis (wild-type OR, 1.33; 95% CI, 1.01-1.75; mutated OR, 1.16; 95% CI, 0.81-1.65). Similar results were observed for total fat intake. For other nutrients and for vegetable and meat food groups no differences in risk for either p53 pathway were observed, independent of the laboratory technique used. Interestingly, in cases with transversion mutations in the p53 gene, an increased risk was observed for saturated fat (OR, 2.00; 95% CI, 0.97-4.14), in contrast to those with mutations at CpG sites (OR, 0.93; 95% CI, 0.55-1.57). An increase in colon-cancer risk for the p53-independent pathway due to fat intake, is more pronounced when using immunohistochemistry. However, mutation analysis is needed to study the possible association with a small group of tumors with transversion mutations.     

Can pictorial warning labels on cigarette packages address smoking-related health disparities? Field experiments in Mexico to assess pictorial warning label content

We investigated the association between diet and head and neck cancer (HNC) risk using data from the International Head and Neck Cancer Epidemiology (INHANCE) consortium. The INHANCE pooled data included 22 case-control studies with 14,520 cases and 22,737 controls. Center-specific quartiles among the controls were used for food groups, and frequencies per week were used for single food items. A dietary pattern score combining high fruit and vegetable intake and low red meat intake was created. Odds ratios (OR) and 95% confidence intervals (CI) for the dietary items on the risk of HNC were estimated with a two-stage random-effects logistic regression model. An inverse association was observed for higher-frequency intake of fruit (4th vs. 1st quartile OR = 0.52, 95% CI = 0.43-0.62, p (trend) < 0.01) and vegetables (OR = 0.66, 95% CI = 0.49-0.90, p (trend) = 0.01). Intake of red meat (OR = 1.40, 95% CI = 1.13-1.74, p (trend) = 0.13) and processed meat (OR = 1.37, 95% CI = 1.14-1.65, p (trend) < 0.01) was positively associated with HNC risk. Higher dietary pattern scores, reflecting high fruit/vegetable and low red meat intake, were associated with reduced HNC risk (per score increment OR = 0.90, 95% CI = 0.84-0.97).     

Consumption of meat,traditional and modern processed meat and colorectal cancer risk among the Moroccan population: A large-scale case–control study

The current study aimed to investigate the relationship between red and white meat subtypes, processed meat (divided into traditional “Khlii, Kaddid” and industrially processed meat) and colorectal cancer (CRC) risk, considering CRC subsites, in Moroccan adults. A case–control study was conducted including 2,906 matched case–control pairs recruited from the five largest university hospitals in Morocco. Dietary data were collected through a validated Food Frequency Questionnaire (FFQ). Multivariable odds ratios (OR) and 95% confidence intervals (CI), for the association of CRC risk with meat consumption (high vs. low intake), were estimated using conditional logistic regression models, adjusted for relevant confounding variables. Overall, consumption of red meat was positively associated with colon cancer and CRC risk (OR = 1.23, 95% CI = 1.05–1.44; OR = 1.14, 95% CI = 1.02–1.27), respectively. In contrast, no significant association was observed between the consumption of red meat and rectal cancer risk (OR = 1.05, 95% = 0.90–1.23). Interestingly, while processed meat from industrial processes was positively associated with colon cancer, rectal cancer and CRC (OR = 1.61, 95% CI = 1.27–2.04; OR = 1.73, 95% CI = 1.34–2.23; OR = 1.67, 95% CI = 1.41–1.98), processed meat prepared using traditional methods was inversely associated with colon cancer and CRC risk (OR = 0.74, 95% CI = 0.57–0.98; OR = 0.77, 95% CI = 0.64–0.93), respectively. Furthermore, positive associations were observed between poultry intake and colon cancer risk among men (OR = 1.27, 95% CI = 1.01–1.59). Our study showed similar associations between the consumption of red meat and CRC risk in Morocco as in developed countries, while inverse associations were found for traditionally processed meat products. This is the first study to investigate the differential effects of traditional vs. westernized processed meat products in a developing country. Other studies are needed to confirm these findings and to understand the physiological pathways underlying these associations.