Common dietary patterns and risk of cancers of the colon and rectum: Analysis from the United Kingdom Women's Cohort Study (UKWCS)

Few prospective cohort studies in the UK have specifically focused on the associations between commonly consumed dietary patterns and colorectal cancer (CRC). The aim of our study was to assess whether red meat, poultry, fish and vegetarian dietary patterns are associated with differences in the incidence of cancers of colon and rectum in the UKWCS. Four common dietary patterns were defined based on a hierarchy of consumption of red meat, poultry and fish for each cohort participant, using a 217‐item food frequency questionnaire. Cox proportional hazards regression was used to provide adjusted hazard ratios (HR) and 95% confidence intervals (CI) for CRC. A total of 32,147 women recruited and surveyed between 1995 and 1998 were followed up for a mean of 17.2 years (426,798 person‐years). A total of 462 incident CRC cases were documented; 335 colon cancers (172 proximal and 119 distal) and 152 in the rectum. In multivariable‐adjusted models, there was no evidence of a reduction in risk of overall CRC (HR = 0.86, 95% CI: 0.66–1.12), colon cancer (HR = 0.77, 95% CI: 0.56–1.05) or rectal cancer (HR = 1.04, 95% CI: 0.66–1.63) when comparing grouped red meat free diets with diets containing red meat. Exploratory analysis suggested a reduced risk of distal colon cancer in grouped red meat free diets (HR = 0.56, 95% CI: 0.34–0.95), though numbers with this outcome were small. These results indicate that a protective association of red meat free diets specifically on distal colon cancer merits confirmation in a larger study.     

Alcohol consumption is associated with an increased risk of distal colon and rectal cancer in Japanese men: the Miyagi Cohort Study

The association between alcohol consumption and the risk of cancer of the proximal or distal colon or rectum remains controversial. We examined this association in a large population-based cohort of Japanese men. In 1990, a self-administered questionnaire on alcohol drinking and other health habits was delivered to 25,279 Japanese men aged 40 to 64 years of age. After exclusion of subjects who gave incomplete responses on alcohol drinking or prevalent cancer cases at the baseline, a total of 21,199 men remained. Of these, 307 men were diagnosed as having colorectal cancer after 11 years of follow-up. Cox proportional hazards regression models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs), with adjustments made for potential confounders. Compared with never drinkers, past and current drinkers had multivariate HRs of 1.1 (95% CI, 0.6-1.9) and 1.6 (95% CI, 1.1-2.2) for colorectal cancer, respectively. A dose-response relationship with current volume of alcohol drinkers was observed for cancer of the distal colon and rectum, but not for proximal colon. The multivariate HRs for distal colon and rectal cancer among current heavy drinkers (45.6 g or more ethanol per day) as compared with never drinkers were 4.2 (1.6-10.7; p for trend=0.0002) and 1.8 (1.1-3.2; p for trend=0.04), respectively. In contrast, no significant linear association was found for proximal colon cancer (p for trend=0.2). These data indicate that alcohol consumption in Japanese men is associated with a statistically significant increased risk of cancer of the distal colon and rectum, but not cancer of the proximal colon.     

Radiation risk of incident colorectal cancer by anatomical site among atomic bomb survivors: 1958–2009

Radiation effects on colorectal cancer rates, adjusted for smoking, alcohol intake and frequency of meat consumption and body mass index (BMI) by anatomical subsite (proximal colon, distal colon and rectum) were examined in a cohort of 105,444 atomic bomb survivors. Poisson regression methods were used to describe radiation-associated excess relative risks (ERR) and excess absolute rates (EAR) for the 1958–2009 period. There were 2,960 first primary colorectal cancers including 894 proximal, 871 distal and 1,046 rectal cancers. Smoking, alcohol intake and BMI were associated with subsite-specific cancer background rates. Significant linear dose–responses were found for total colon (sex-averaged ERR/Gy for 70 years old exposed at age 30 = 0.63, 95% confidence interval [CI]: 0.34; 0.98), proximal [ERR = 0.80, 95% CI: 0.32; 1.44] and distal colon cancers [ERR = 0.50, 95% CI: 0.04; 0.97], but not for rectal cancer [ERR = 0.023, 95% CI: −0.081; 0.13]. The ERRs for proximal and distal colon cancers were not significantly different (p = 0.41). The ERR decreased with attained age for total colon, but not for proximal colon cancer, and with calendar year for distal colon cancer. The ERRs and EARs did not vary by age at exposure, except for decreasing trend in EAR for proximal colon cancer. In conclusion, ionizing radiation is associated with increased risk of proximal and distal colon cancers. The ERR for proximal cancer persists over time, but that for distal colon cancer decreases. There continues to be no indication of radiation effects on rectal cancer incidence in this population.     

Red meat, chicken, and fish consumption and risk of colorectal cancer.

BACKGROUND: Red meat and processed meat consumption have been associated with increased risk of colorectal cancer in some, but not all, relevant cohort studies. Evidence on the relationship between risk of colorectal cancer and poultry and fish consumption is inconsistent. METHODS: We conducted a prospective cohort study of 37,112 residents of Melbourne, Australia recruited from 1990 to 1994. Diet was measured with a food frequency questionnaire. We categorized the frequency of fresh red meat, processed meat, chicken, and fish consumption into approximate quartiles. Adenocarcinomas of the colon or rectum were ascertained via the Victorian Cancer Registry. RESULTS: We identified 283 colon cancers and 169 rectal cancers in an average of 9 years of follow-up. For rectal cancer, the hazard ratios [95% confidence intervals (95% CI)] in the highest quartile of consumption of fresh red meat and processed meat were 2.3 (1.2-4.2; P for trend = 0.07) and 2.0 (1.1-3.4; P for trend = 0.09), respectively. The corresponding hazard ratios (95% CIs) for colon cancer were 1.1 (0.7-1.6; P for trend = 0.9) and 1.3 (0.9-1.9; P for trend = 0.06). However, for neither type of meat was the heterogeneity between subsites significant. Chicken consumption was weakly negatively associated with colorectal cancer (hazard ratio highest quartile, 0.7; 95% CI, 0.6-1.0; P for trend = 0.03), whereas hazard ratios for fish consumption were close to unity. CONCLUSION: Consumption of fresh red meat and processed meat seemed to be associated with an increased risk of rectal cancer. Consumption of chicken and fish did not increase risk.     

Alcohol consumption, type of alcoholic beverage and risk of colorectal cancer at specific subsites

Within the Netherlands Cohort Study on diet and cancer, we investigated associations between total alcohol consumption, specific alcoholic beverage consumption and risk of colorectal cancer (CRC) according to anatomical subsite. Hazard Ratios (HR) and 95% confidence intervals (CI) were estimated using Cox proportional hazards models. Analyses were performed on 2,323 CRC cases, available after 13.3 years of follow-up. Compared to abstaining, alcohol consumption of >/=30.0 g/day ( approximately 3 alcoholic drinks) was positively associated with the risk of CRC (HR: 1.32, 95% CI: 1.06-1.65). Analyses restricted to subjects who reported to have consumed equal amounts of alcohol 5 years before baseline compared to baseline, showed elevated risk estimates for consumers of >/=30.0 g of total alcohol per day as well (HR: 1.53, 95% CI: 1.16-2.01). Suggestive of a subsite-specific effect, cancer risk seemed to increase from proximal colon through rectum; HR: 1.29, 95% CI: 0.85-1.96 for proximal colon cancer, HR: 1.41, 95% CI: 0.94-2.11 for distal colon cancer, HR: 2.07, 95% CI: 1.03-4.18 for rectosigmoid cancer and HR: 1.69, 95% CI: 1.08-2.64 for rectal cancer. No associations were observed between consumption of alcoholic beverages and CRC risk when compared with the nondrinkers of the specific beverage and after adjustment for total alcohol intake. No evidence was found for sex-specific effects of alcohol and alcoholic beverages. In conclusion, our data showed a positive association between alcohol consumption and risk of CRC, which seemed to be mainly explained by the alcoholic content of alcoholic beverages, rather than other constituents. Also, cancer risk may vary according to anatomical subsite.     

Meat, fish and fat intake in relation to subsite-specific risk of colorectal cancer: The Fukuoka Colorectal Cancer Study

High intake of red meat has been associated with increased risk of colorectal cancer in Western countries. There has been much interest in the role of n-3 polyunsaturated fatty acids (PUFA) in colorectal cancer prevention, but epidemiological findings are limited and inconsistent. The objective of our study was to examine associations of meat, fish and fat intake with risk of colorectal cancer, paying particular attention to the subsite within the colorectum. Data were from the Fukuoka Colorectal Cancer Study, a population-based case-control study, covering 782 cases and 793 controls. Diet was assessed by interview, using newly developed personal-computer software for registering semiquantitative food frequencies. The intake of beef/pork, processed meat, total fat, saturated fat or n-6 PUFA showed no clear association with the overall or subsite-specific risk of colorectal cancer. There was an almost significant inverse association between n-3 PUFA and the risk of colorectal cancer; the covariate-adjusted odds ratio for the highest (median 3.94 g/day) versus lowest (median 1.99 g/day) quintile of energy-adjusted intake was 0.74 (95% confidence interval 0.52-1.06, trend P=0.050). The consumption of fish and fish products was similarly inversely related to the risk although the association was not statistically significant. These associations were more evident for distal colon cancer; adjusted odds ratio for the highest versus lowest quintile of n-3 PUFA intake was 0.56 (95% confidence interval 0.34-0.92, trend P=0.02). Our findings do not support the hypothesis that consumption of red meat increases colorectal cancer risk but do suggest that high intake of fish may decrease the risk, particularly of distal colon cancer.     

Effects of alcohol consumption on the risk of colorectal cancer among men by anatomical subsite (Canada)

Objective: To estimate the effects of alcohol consumption on the risk of colorectal cancer according to anatomical subsite. Methods: Between 1979 and 1985 a population-based case–control study of cancer at multiple sites was carried out in Montréal. This analysis was restricted to the 585 cases with adenocarcinoma of the large bowel, aged 35–70 years, who underwent face-to-face interviews. Controls (n = 500) were selected either from electoral lists or by random-digit dialing and were frequency-matched to the cases on age. Polytomous logistic regression was used to estimate the risk of cancer of the proximal colon, distal colon, and rectum in relation to the consumption of alcoholic beverages. Results: Daily consumption of alcohol of any type was associated with increased risks of cancer of the distal colon [odds ratio (OR) = 2.3; 95% confidence interval (CI) 1.4–3.7] and the rectum (OR = 1.6; 95% CI 1.0–2.6), but not with an increased risk of cancer of the proximal colon (OR = 1.0; 95% CI: 0.6–1.7). When type of beverage was considered, beer showed strong associations with cancer at all three subsites (ORs among the heaviest drinkers ranging from 1.8 to 2.4), spirits showed weaker associations with cancer at all three subsites (ORs ranging from 1.4 to 1.6), and wine showed null associations. Conclusions: The results are consistent with the hypothesis that consumption of alcoholic beverages increases the risk of colorectal cancer. The evidence is strongest for effects on the distal colon and rectum, and, among the three types of beverage, it most strongly implicates beer.     

Meat intake,cooking methods and risk of proximal colon,distal colon and rectal cancer: The Norwegian Women and Cancer (NOWAC) cohort study

Red and processed meat intake is an established risk factor for colorectal cancer (CRC), but epidemiological evidence by subsite and sex is still limited. In the population‐based Norwegian Women and Cancer cohort, we examined associations of meat intake with incident proximal colon, distal colon and rectal cancer, in 84,538 women who completed a validated food frequency questionnaire (FFQ) during 1996–1998 or 2003–2005 (baseline or exposure update) at age 41–70 years, with follow‐up by register linkages through 2009. We also examined the effect of meat cooking methods in a subsample (n = 43,636). Multivariable hazard ratios (HRs) were estimated by Cox regression. There were 459 colon (242 proximal and 167 distal), and 215 rectal cancer cases with follow‐up ≥ 1 (median 11.1) year. Processed meat intake ≥60 vs. <15 g/day was associated with significantly increased cancer risk in all subsites with HRs (95% confidence interval, CI) of 1.69 (1.05–2.72) for proximal colon, 2.13 (1.18–3.83) for distal colon and 1.71 (1.02–2.85) for rectal cancer. Regression calibration of continuous effects based on repeated 24‐hr dietary recalls, indicated attenuation due to measurement errors in FFQ data, but corrected HRs were not statistically significant due to wider CIs. Our study did not support an association between CRC risk and intake of red meat, chicken, or meat cooking methods, but a high processed meat intake was associated with increased risk of proximal colon, distal colon and rectal cancer. The effect of processed meat was mainly driven by the intake of sausages.     

Meat consumption and colorectal cancer risk in Japan: The Takayama study

Compared with the abundant data from Western countries, evidence regarding meat consumption and colorectal cancer is limited in the Japanese population. We evaluated colorectal cancer risk in relation to meat consumption in a population‐based prospective cohort study in Japan. Participants were 13 957 men and 16 374 women aged ≥35 years in September 1992. Meat intake, assessed with a validated food frequency questionnaire, was controlled for the total energy intake. The incidence of colorectal cancer was confirmed through regional population‐based cancer registries and histological identification from colonoscopy in two main hospitals in the study area. From September 1992 to March 2008, 429 men and 343 women developed colorectal cancer. After adjustments for multiple confounders, a significantly increased relative risk of colorectal cancer was observed in the highest versus lowest quartile of the intake of total and red meat among men; the estimated hazard ratios were 1.36 (95% CI: 1.03, 1.79) for total meat (P for trend = 0.022), and 1.44 (95% CI: 1.10, 1.89) for red meat (P for trend = 0.009). A positive association between processed meat intake and colon cancer risk was also observed in men. There was no significant association between colorectal cancer and meat consumption in women. These results suggest that the intake of red and processed meat increases the risk of colorectal or colon cancer among Japanese men. Abstaining from excessive consumption of meat might be protective against developing colorectal cancer.     

Dietary soy and isoflavone intake and risk of colorectal cancer in the Japan public health center-based prospective study

Several experimental studies have reported that the anticarcinogenic properties of dietary soy play an important role in preventing colorectal cancer. However, few epidemiologic studies have examined this association in general populations and their findings have been inconsistent. We investigated the association between dietary soy and isoflavone intake and incidence of colorectal cancer in a prospective cohort study of 83,063 Japanese men and women, ages 45 to 74 years. Dietary soy and isoflavone intake was measured through a validated food frequency questionnaire in 1995 and 1998. Throughout 2004, a total of 886 cases of colorectal cancer were newly identified (291 proximal colon, 286 distal colon, and 277 rectum). The hazard ratios and 95% confidence intervals (95% CIs) were estimated by fitting a Cox proportional hazards model. The intake of isoflavones, miso soup, and soy food was not associated with colorectal cancer in either men or women. By colorectal cancer subsite, the risk of proximal colon cancer in men decreased with increasing consumption of isoflavones, miso soup, and soy food. Compared with men in the lowest quartiles of isoflavones, miso soup, and soy food intake, the hazard ratios in the highest quartiles were 0.55 (95% CI, 0.33-0.92), 0.72 (95% CI, 0.43-1.21), and 0.51 (95% CI, 0.30-0.87), respectively. The results showed no association for distal colon and rectal cancer in men or for subsites of colorectal cancer in women. These findings suggest that the intake of isoflavones, miso soup, and soy food has no substantial effect on the risk of colorectal cancer in Japanese men and women.     

Intake of n-3 and n-6 polyunsaturated fatty acids and development of colorectal cancer by subsite: Japan Public Health Center-based prospective study

To date, epidemiologic studies investigating intake of n-3 and n-6 polyunsaturated fatty acids and risk of colorectal cancer are limited, and results remain inconsistent. This is the first prospective study to show the association by subsite (proximal colon, distal colon, rectum). To clarify the role of n-3 and n-6 polyunsaturated fatty acids intake in colon carcinogenesis, we conducted a large, population-based prospective study, characterized by high fish consumption and a wide range of n-3 polyunsaturated fatty acids intakes. Subjects were followed from response to a lifestyle questionnaire in 1995-1999 through 2006. During 827,833 person-years of follow-up (average 9.3 years), we identified 1,268 new colorectal cancer cases (521 colon and 253 rectal for men; 350 colon and 144 rectal for women). Compared to the lowest quintile, the relative risk and 95% confidence interval of developing cancer among the fifth quintile of marine n-3 polyunsaturated fatty acids intake were 0.60 and 0.31-1.14, respectively (p for trend = 0.04) in the colon in women and 0.35 and 0.14-0.88 (p for trend = 0.05) and 1.82 and 0.79-4.20 (p for trend = 0.16) in the proximal and distal colon, respectively, in men. For rectal cancer, the dose response for marine n-3 polyunsaturated fatty acids s was unclear; rather, we observed U-shaped associations in men and women. We found no evidence that n-6 polyunsaturated fatty acids increases or the n-3/n-6 ratio decreases the risk of colorectal cancer. Our results suggest that intake of marine n-3 polyunsaturated fatty acids may be inversely related to the risk of cancer in the proximal site of the large bowel.     

Dietary patterns and subsequent colorectal cancer risk by subsite: a prospective cohort study

In order to investigate the associations between dietary patterns and the risk of colorectal cancer by subsite in Japan, the baseline data from a population-based cohort study of 20,300 men and 21,812 women were analyzed. We conducted factor analysis and identified 3 major dietary patterns, "healthy," "traditional" and "Western," and calculated the factor scores of each pattern for individuals. During 10 years of follow-up, 370 colorectal cancer cases were identified. We found a positive association between the traditional pattern and colon cancer risk in women [rate ratio for highest quartile (RR) = 2.06; 95% CI = 1.10-3.84; p for trend = 0.11], but not in men. This positive association was slightly stronger for proximal colon cancer (RR = 2.07; 95% CI = 0.84-5.12) than for distal colon cancer (RR = 1.84; 95% CI = 0.75-4.50). After multivariate adjustment, the Western dietary pattern was also positively associated with colon cancer risk in females (RR = 2.21; 95% CI = 1.10-4.45), with the strongest associations being observed for females with distal colon cancer (RR = 3.48; 95% CI = 1.25-9.65). We did not observe any significant association between the healthy dietary pattern and colon cancer risk. For rectal cancer, no significant associations were found for the 3 dietary patterns. In conclusion, we found that the traditional and the Western dietary patterns were positively associated with colon cancer risk in females.     

p53 Arg72Pro polymorphism and risk of colorectal adenoma and cancer

A single nucleotide polymorphism (SNP) at codon 72 of the p53 gene (Arg72Pro) alters the p53 protein structure and affects its activity. We investigated this SNP in relation to colorectal adenoma and cancer among men and women from case-control studies nested within the Nurses' Health Study, the Health Professionals Follow-up Study and the Physicians' Health Study. Among 856 colorectal adenoma cases and 1,184 controls, we observed a modest association with p53 Arg72Pro genotype (multivariate odds ratio (OR) = 1.25, 95% confidence interval (CI) = 1.04-1.50 for Arg/Pro and Pro/Pro vs. Arg/Arg). This association did not vary by colorectal site or by sex. Among 442 colorectal cancer cases and 904 controls, we observed no significant overall association between p53 Arg72Pro genotype and colorectal cancer (multivariate OR = 1.14, 95% CI = 0.90-1.45). However, when colorectal site and sex was accounted for, the Pro carrier genotypes compared to Arg/Arg were associated with an increased risk of proximal colon cancers in women (multivariate OR = 2.59, 95% CI = 1.49-4.52) though not with distal colon or rectal cancers, while among men the same genotypes were associated with an increased risk of distal colon cancers (multivariate OR = 2.09, 95% CI = 1.28-3.40) but not proximal colon or rectal cancers. Our results suggest that Arg72Pro may play a role in the early stages of colorectal neoplasia and possibly in progression to invasive disease, depending on site and sex.     

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

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

Mismatch repair polymorphisms and the risk of colorectal cancer

Rare germline variants in mismatch repair genes have been linked to hereditary nonpolyposis colorectal cancer; however, it is unknown whether common polymorphisms in these genes alter the risk of colorectal cancer. To examine the association between common variants in mismatch repair genes and colorectal cancer, we conducted a case-cohort study within the CLUE II cohort. Four single nucleotide polymorphisms in 3 mismatch repair genes (MSH3 R940Q, MSH3 T1036A, MSH6 G39E and MLH1 I219V) were genotyped in 237 colorectal cancer cases and a subcohort of 2,189 participants. Incidence rate ratios (RRs) and 95% confidence intervals (95% CIs) for each polymorphism were estimated. The MSH3 1036A variant was found to be associated with an increased risk of colorectal cancer (RR=1.28, 95% CI: 0.94-1.74 and RR=1.65, 95% CI: 1.01-2.70 for the AT and TT genotypes, respectively, with p(trend)=0.02), particularly proximal colon cancer. Although the MSH3 940Q variant was only weakly associated with colorectal cancer overall (p(trend)=0.07), it was associated with a significant increased risk of proximal colon cancer (RR=1.69, 95% CI: 1.10-2.61 and RR=2.68, 95% CI: 0.96-7.47 for the RQ and QQ genotypes, respectively with p(trend)=0.005). Processed meat intake appeared to modify the association between the MSH3 polymorphisms and colorectal cancer (p(interaction) < 0.10 for both). No association was observed with the MSH6 and MLH1 polymorphisms overall. This study suggests that common polymorphisms in the mismatch repair gene, MSH3, may increase the risk of colorectal cancer, especially proximal colon cancer.     

Coffee consumption and the risk of colorectal cancer by anatomical subsite in Japan: Results from the HERPACC studies

Consumption of coffee, a popular beverage worldwide, has been associated with lower colorectal cancer (CRC) risk. Although CRC exhibits different biological characteristics by anatomical subsite, the possibly heterogeneous impact of coffee on CRC by anatomical subsite has remained unclear. Here, we conducted two case‐control studies to examine the association between coffee consumption and CRC risk as well as risk by anatomic subsite among Japanese using data from the Hospital‐based Epidemiological Research Program at Aichi Cancer Center I and II (HERPACC‐I and II). Subjects were enrolled in HERPACC‐I between 1988 and 2000 and in HERPACC‐II between 2001 and 2005. Coffee consumption was measured with a self‐administered questionnaire. A conditional logistic regression model was used to calculate odds ratios (ORs) of CRC with coffee consumption, adjusted for potential confounders of age, smoking, alcohol drinking, red meat intake, BMI, exercise, family history of CRC, and diabetes mellitus history. We estimated summary ORs by pooling study‐specific ORs with a fixed effects model. In total, 2,696 CRC cases and 13,480 non‐cancer outpatients as controls were included. Overall, compared to non‐drinkers, ORs of less than 1 cup/day, 1–2 cups/day and 3 or more cups/day for CRC were 0.88 (95% CI: 0.77–1.00), 0.90 (95% CI: 0.80–1.01) and 0.78 (95% CI: 0.65–0.92), respectively (trend‐p = 0.009). Subsite‐specific analysis revealed a significant inverse linear trend between coffee consumption and distal colon cancer (p‐trend = 0.048), and a tendency toward a lower risk of rectal cancer (p‐trend = 0.068). These findings suggest that coffee consumption might impact the prevention of CRC, especially distal colon cancer.     

Coffee consumption and risk of colorectal cancer in a population-based prospective cohort of Japanese men and women

We prospectively examined the association between coffee consumption and the risk of developing colorectal cancer in a large population-based cohort study (the JPHC Study) of Japanese men and women. Data were analyzed from a population-based cohort of 96,162 subjects (46,023 men and 50,139 women). A total of 1,163 incident colorectal cancers were identified during the follow-up period, including 763 cases of colon cancer and 400 of rectal cancer. We observed a significant inverse association between coffee consumption and the risk of developing invasive colon cancer among women. Compared with those who almost never consumed coffee, women who regularly consumed 3 or more cups of coffee per day had a RR of 0.44 (95% CI = 0.19-1.04; p for trend = 0.04) after adjustment for potential confounding factors. However, no significant association was found for rectal cancer in women. In men, no significant decrease was observed in any colorectal cancer site. Further, additional analyses on the association of green tea consumption with colorectal cancer risk found no significant association in men or women. These findings suggest that coffee consumption may lower the risk of colon cancer among Japanese women.     

Diet and vitamin or mineral supplementation and risk of colon cancer by subsite in Canada.

The study assesses the association of diet and vitamin or mineral supplementation with risk of proximal or distal colon cancer. Mailed questionnaires were completed by 1723 newly diagnosed, histologically confirmed colon cancer cases and 3097 population controls between 1994 and 1997 in seven Canadian provinces. Measurement included information on socio-economic status, physical activity, smoking habits, alcohol use, diet and vitamin or mineral supplementation. Odds ratios and 95% confidence intervals were derived through unconditional logistic regression. Linear regression was used to examine that dietary factors affect body mass index. The strongest positive associations between colon cancer risk and increasing total fat intake were observed for proximal colon cancer in men and for distal colon cancer in both men and women. Increased consumption of vegetables, fruit and whole-grain products did not reduce the risk of colon cancer. A modest reduction in distal colon cancer risk was noted in women who consumed yellow-orange vegetables. Significant positive associations were observed between proximal colon cancer risk in men and consumption of red meat and dairy products, and between distal colon cancer risk in women and total intake of meat and processed meat. We also saw strong associations between bacon intake and both subsites of colon cancer in women. When men were compared with women directly by subsite however, the results did not show a corresponding association. A significantly reduced risk of distal colon cancer was noted in women only with increasing intake of dairy products and of milk. Among men and women taking vitamin and mineral supplements for more than 5 years, significant inverse associations with colon cancer were most pronounced among women with distal colon cancer. These findings suggest that dietary risk factors for proximal colon cancer may differ from those for distal colon cancer.     

Trends in colorectal cancer incidence in Norway by gender and anatomic site: an age-period-cohort analysis.

The purpose of this study was to examine the secular trend of colorectal cancer in Norway by gender and subsite. All new cases of cancer in proximal colon, distal colon and rectum diagnosed between 1958 and 1997 in Norway were included in the study, altogether 34 202 and 34 097 cases for men and women, respectively. The incidence data were fitted separately for each gender and subsite to an age-period-cohort model. An increase in incidence of colorectal cancer was seen from 1958 to 1997 for both men and women, although a moderate attenuation of the increase has taken place in the last 15-20 years. This observation is most pronounced for cancer of the distal colon, but is also evident for proximal colonic and rectal cancers. For the distal colon and rectum, the period effect is more important than the cohort effect for both genders, whilst opposite for the proximal colon. The main estimated trend for cohort effects is a steady increase for both men and women, apart from an unexpected drop in incidence among the cohorts born during or shortly after World War II. These findings indicate that different aetiological risk factors may act on cancers of the proximal and distal part of the large bowel and further suggest that exogenous risk factors acting very early in life may play a more important role for colorectal cancer than previously recognized.     

Meat mutagens and risk of distal colon adenoma in a cohort of U.S. men.

Cooking meats at high temperatures and for long duration produces heterocyclic amines and other mutagens. These meat-derived mutagenic compounds have been hypothesized to increase risk of colorectal neoplasia, but prospective data are unavailable. We examined the association between intakes of the heterocyclic amines 2-amino-3,8-dimethylimidazo[4,5,-f]quinoxaline (MeIQx), 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), 2-amino-3,4,8-trimethylimidazo[4,5,-f]quinoxaline (DiMeIQx), and meat-derived mutagenicity (MDM) and risk of distal colon adenoma using a cooking method questionnaire administered in 1996 in the Health Professionals Follow-up Study cohort. Between 1996 and 2002, 581 distal colon adenoma cases were identified. Higher intake of MDM was marginally associated with increased risk of distal adenoma [fourth versus lowest quintile: odds ratio (OR), 1.39; 95% confidence interval (95% CI), 1.05-1.84; highest versus lowest quintile: OR, 1.29; 95% CI, 0.97-1.72; P(trend) = 0.08]. Adjusting for total red meat or processed meat intake did not explain those associations. Our data also suggested a positive association between higher MeIQx (highest versus lowest quintile: OR, 1.28; 95% CI, 0.95-1.71; P(trend) = 0.22) and risk of adenoma, but this association was attenuated after adjusting for processed meat intake. DiMeIQx and PhIP did not seem to be associated with risk of adenoma. In conclusion, higher consumption of mutagens from meats cooked at higher temperature and longer duration may be associated with higher risk of distal colon adenoma independent of overall meat intake. Because mutagens other than heterocyclic amines also contribute to MDM, our results suggest that mutagens other than heterocyclic amines in cooked meats may also play a role in increasing the risk of distal adenoma.