Coffee consumption and the risk of colorectal cancer: a prospective cohort study in Japan

An inverse association between coffee consumption and the risk of colorectal cancer has been reported in several case-control studies, but results from prospective cohort studies have been inconclusive. We conducted a prospective cohort study among a Japanese population to clarify the association between coffee consumption and the risk of colorectal cancer incidence. We used data from the Miyagi Cohort Study for this analysis. Usable self-administered questionnaires about coffee consumption were returned from 22,836 men and 24,769 women, aged 40-64 years, with no previous history of cancer. We used the Cox proportional-hazard regression model to estimate hazard ratios and 95% confidence intervals. During 11.6 years of follow-up (425,303 person-years), we identified 457 cases of colorectal cancer. Coffee consumption was not associated with the incidence of colorectal, colon or rectal cancer. The multivariate-adjusted hazard ratio (95% confidence interval) of colorectal cancer incidence for 3 or more cups of coffee per day as compared with no consumption was 0.95 (0.65-1.39) for men and women (p for trend = 0.55), 0.91 (0.56-1.46) for men (p for trend = 0.53) and 1.16 (0.60-2.23) for women (p for trend = 0.996). Coffee consumption was also not associated with incidence of either proximal or distal colon cancer. We conclude that coffee consumption is not associated with the incidence risk of colorectal cancer in the general population in Japan.     

Coffee consumption and risk of colorectal cancer: A systematic review and meta‐analysis of prospective cohort studies

An inverse association between coffee consumption and the risk of colorectal cancer has been found in several case‐control studies, but such an association was not consistent in prospective cohort studies. We conducted a systematic meta‐analysis of prospective cohort studies on coffee consumption and colorectal cancer published up to June 2008. We combined relative risks (RR) for colorectal cancer comparing high vs. low categories of coffee consumption using random‐effects models. We identified 12 eligible cohort studies, which included 646,848 participants and 5,403 cases for colorectal cancer. The summarized result of the meta‐analysis comparing high‐ vs. low‐consumption categories showed no significant effect of coffee consumption on colorectal cancer risk (RR = 0.91; 95% confidence intervals [CI]: 0.81–1.02). The RR was 0.93 (95% CI: 0.71–1.22) when considering 4 studies conducted in the United States of America, 0.91 (95% CI: 0.76–1.10) for 5 studies from Europe, and 0.83 (95% CI: 0.62–1.10) for 3 Japanese studies. No significant differences by sex and cancer‐site were found, but there was a slight suggestion of an inverse association between coffee consumption and colon cancer in women (RR = 0.79; 95% CI: 0.60–1.04), especially Japanese women (RR = 0.62; 95% CI: 0.37–1.05). The suggestive inverse associations were slightly stronger in studies that controlled for smoking and alcohol, and in studies with shorter follow‐up times. Information on coffee type, its serving size, or brewing method may provide a better understanding of this reassuring result and the real role of coffee on colorectal cancer risk. © 2008 Wiley‐Liss, Inc.     

Coffee consumption and risk of endometrial cancer: findings from a large up-to-date meta-analysis

Several epidemiological studies have examined the association between coffee drinking and risk of endometrial cancer. To provide a quantitative assessment of this association, we conducted a meta-analysis of observational studies published up to October 2011 through a search of MEDLINE and EMBASE databases and the reference lists of retrieved article. Pooled relative risks (RRs) with 95% confidence intervals (CIs) were calculated using a random-effects model, and generalized least square trend estimation was used to assess dose-response relationships. A total of 16 studies (10 case-control and six cohort studies) on coffee intake with 6,628 endometrial cancer cases were included in the meta-analysis. The pooled RR of endometrial cancer for the highest versus lowest categories of coffee intake was 0.71 (95% CI: 0.62-0.81; p for heterogeneity = 0.13). By study design, the pooled RRs were 0.69 (95% CI: 0.55-0.87) for case-control studies and 0.70 (95% CI: 0.61-0.80) for cohort studies. By geographic region, the inverse association was stronger for three Japanese studies (pooled RR = 0.40; 95% CI: 0.25-0.63) than five studies from USA/Canada (pooled RR = 0.69; 95% CI: 0.60-0.79) or eight studies from Europe (pooled RR = 0.79; 95% CI: 0.63-0.99). An increment of one cup per day of coffee intake conferred a pooled RR of 0.92 (95% CI: 0.90-0.95). In conclusion, our findings suggest that increased coffee intake is associated with a reduced risk of endometrial cancer, consistently observed for cohort and case-control studies. More large studies are needed to determine subgroups to obtain more benefits from coffee drinking in relation to endometrial cancer risk.     

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.     

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.     

Coffee drinking and colorectal cancer and its subsites: A pooled analysis of 8 cohort studies in Japan

Coffee is a rich source of bioactive compounds that have potential anticarcinogenic effects. However, it remains unclear whether coffee drinking is associated with colorectal cancer. Also, despite different etiological factors involved in gut physiology, few studies have investigated this association by anatomical site of the lesion. To address these issues, this study examined the association between coffee drinking and colorectal cancer in a pooled analysis from 8 cohort studies conducted in Japan. Among 320,322 participants followed up for 4,503,274 person‐years, 6,711 incident colorectal cancer cases were identified. Study‐specific hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazards models and then pooled using the random effects model. Coffee drinking was not materially associated with colorectal cancer risk in men or women (pooled HR 0.92, 95% CI 0.82–1.03 in men and pooled HR 0.90, 95% CI 0.76–1.07 in women). Analysis by subsite showed a lower risk of colon cancer among female drinkers of ≥3 cups coffee/day (pooled HR 0.80, 95% CI 0.64–0.99). There was no such association in men. Coffee drinking was not associated with risk of rectal cancer in men or women. Results were virtually the same among never smokers except for an increased risk of rectal cancer associated with frequent coffee consumption. Coffee drinking may be associated with lower risk of colon cancer in Japanese women.     

Coffee consumption and breast cancer risk among BRCA1 and BRCA2 mutation carriers

Although there are several plausible biologic mechanisms whereby coffee consumption might influence the risk of breast cancer, epidemiologic evidence is limited. We assessed the association between coffee consumption and breast cancer risk among high-risk women who carry BRCA mutations. We performed a matched case-control analysis on 1,690 women with a BRCA1 or BRCA2 mutation from 40 centers in 4 countries. Average lifetime coffee consumption was estimated via a self-administered questionnaire. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using conditional logistic regression. After adjustment for potential confounders, the ORs for breast cancer in BRCA carriers who habitually drank 0, 1-3, 4-5 and 6 or more cups of coffee were 1.00, 0.90 (95% CI 0.72-1.12), 0.75 (95% CI 0.47-1.19) and 0.31 (95% CI 0.13-0.71; p-trend = 0.02). The effect was limited to the consumption of caffeinated coffee. These results suggest that among women with BRCA gene mutation, coffee consumption is unlikely to be harmful and that high levels of consumption may in fact be related to reduced breast cancer risk.     

Coffee and tea consumption and risk of hepatocellular carcinoma in Italy

The role of coffee in the aetiology of hepatocellular carcinoma has raised great interest. In Italy, coffee consumption is high, thus allowing the investigation of the topic over a broad range of consumption. A hospital-based case-control study was conducted in Italy in 1999-2002, including 185 incidents, histologically confirmed cases of hepatocellular carcinoma aged 43-84 years. Controls were 412 subjects admitted to the same hospitals' networks for acute, non-neoplastic diseases unrelated to diet. Coffee and tea consumption were assessed using a validated food-frequency questionnaire. Odds ratios (ORs) and corresponding the 95% confidence intervals (CI) were computed using unconditional multiple logistic regression, adjusting for hepatitis viruses seropositivity, alcohol intake, smoking habits and other potential confounding factors. Compared to people who drunk <14 cups/week of coffee, the risk of hepatocellular carcinoma decreased for increasing levels of consumption (OR=0.4, 95% CI: 0.2-1.1 for >or=28 cups/week, p for trend = 0.02). In the present study, inverse relations were observed across strata of hepatitis C and, B virus infections and alcohol drinking. No significant association emerged with consumption of decaffeinated coffee (OR=0.7, 95% CI=0.2-2.5) or tea (OR=1.4, 95% CI=0.8-2.7). The present study supports the hypothesis of a favourable effect of coffee, though not decaffeinated coffee and tea, on the risk on hepatocellular carcinoma.     

Subsite-specific risk factors for colorectal cancer: a hospital-based case-control study in Japan

To investigate the subsite-specific risk factors for colorectal cancer, we conducted a case-control study, using a common questionnaire which inquired about general lifestyles over the past five years (1988–92), at the Aichi Cancer Center Hospital, Nagoya, Japan. This study compared 432 patients with histopathologically diagnosed colorectal cancer (94 proximal colon [cecum, ascending colon, transverse colon]; 137 distal colon [descending colon, sigmoid colon]; 201 rectum [rectosigmoid, rectum]); and 31,782 first-visit outpatient controls who were free from cancer. In both genders, habitual smoking selectively increased the risk for rectum cancer. Soft or loose feces increased the risk for all subsites of colorectal cancer, particularly in female cancer (odds ratio [OR]=4.5). Among female dietary habits, Japanese-style foods decreased the risk factors for distal colon cancer, but increased the risk for proximal colon cancer. These results suggested that the risk factors for colorectal cancer differ by subsite among such a low-risk population as the Japanese. It is suggested also that irritable bowel (soft or loose feces) might be associated with distal subsites of colorectal cancer, independently or combined with habitual smoking. Cancer Causes and Control 1995, 6, 14–22.Drs Inoue and Tajima, Ms Hirose, and Drs Hamajima and Takezaki are with the Division of Epidemiology, Aichi Cancer Center Research Institute, Nagoya, Japan. Authors are also affiliated with the Department of Gastroenterological Surgery, Aichi Cancer Center Hospital, Nagoya, Japan (Drs Hirai and Kato), and the Department of Preventive Medicine, Nagoya University School of Medicine, Nagoya, Japan (Drs Inoue and Ohno). Address correspondence to Dr Inoue, Division of Epidemiology, Aichi Cancer Center Research Institute, 1-1 Kanokoden, Chikusa-ku, Nagoya, Japan, 464. This study was funded in part by a Grant-in-Aid for Cancer Research (4-2) and the Comprehensive 10-year Strategy for Cancer Control from the Ministry of Health and Welfare, Japan.     

Cigarette smoking and the risk of gastric cancer: a pooled analysis of two prospective studies in Japan

To examine the association between cigarette smoking and the risk of gastric cancer, we conducted a pooled analysis of 2 population-based prospective cohort studies in rural northern Japan. Cohort 1 included 9,980 men (>or=40 years old) and Cohort 2 included 19,412 men (40-64 years old). The subjects completed a self-administered questionnaire on cigarette smoking and other health habits. We identified 228 cases of gastric cancer among Cohort 1 subjects (9 years of follow-up with 74,073 person-years) and 223 among Cohort 2 subjects (7 years of follow-up with 141,675 person-years). From each cohort, we computed the relative risk (RR) and 95% confidence interval (CI) of gastric cancer associated with smoking using a Cox regression analysis and pooled these estimates to obtain summary measures. The pooled multivariate RRs (95% CIs) for current smokers and past smokers compared to subjects who had never smoked were 1.84 (1.39-2.43) and 1.77 (1.29-2.43), respectively. The higher number of cigarettes smoked per day among current smokers was associated with a linear increase in risk (trend p < 0.05). The significant increase in risk for past smokers remained for up to 14 years after cessation. An increased risk was noted for cancer of the antrum but not for cardia or body lesions. The risk was increased for both differentiated and nondifferentiated histologic subtypes. Our findings support the hypothesis that cigarette smoking is a risk factor for gastric 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.     

Folate intake and colorectal cancer risk: a meta-analytical approach

Adequate consumption of folate may reduce the risk of colorectal cancer. We performed a meta-analysis of 7 cohort and 9 case-control studies that examined the association between folate consumption and colorectal cancer risk. In cohort studies, the association between folate consumption and colorectal cancer risk was stronger for dietary folate (folate from foods alone; relative risk for high vs. low intake = 0.75; 95% CI = 0.64-0.89) than for total folate (folate from foods and supplements; relative risk for high vs. low intake = 0.95; 95% CI = 0.81-1.11) and there was no significant heterogeneity between studies. There was significant heterogeneity between case-control studies. These results offer some support for the hypothesis that folate has a small protective effect against colorectal cancer but confounding by other dietary factors cannot be ruled out.     

Dietary fatty acids and colorectal cancer risk in men: A report from the Shanghai Men's Health Study and a meta‐analysis

Evidence from animal models suggests that dietary fatty acids have both anticancer and tumor‐promoting effects. Whether dietary fatty acids are associated with colorectal cancer (CRC) in humans remains inconclusive. We investigated associations between dietary fatty acids and risk of CRC among 59 986 men who participated in the Shanghai Men's Health Study (SMHS), an ongoing population‐based prospective cohort study. We identified 876 incident CRC cases in the SMHS during a mean follow‐up of 9.8 years. Associations between dietary fatty acid intake and CRC risk were evaluated by Cox proportional hazard regression analyses. Consumption of saturated fatty acids (SFA), monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA) was not significantly associated with CRC risk. Multivariate hazard ratios (HRs) and respective 95% confidence intervals (CIs) for Quartile 4 vs Quartile 1 were 0.92 (0.74‐1.14; P_trend = 0.47) for SFA, 0.95 (0.79‐1.16; P_trend = 0.74) for MUFA and 1.18 (0.95‐1.46; P_trend = 0.21) for PUFA. No significant associations were found for total n‐6 PUFA or total n‐3 PUFA. Additionally, we performed a meta‐analysis to summarize results from the present study and 28 reports from 26 additional cohorts, which supported the overall null association between dietary fatty acid intake and CRC risk among men. Docosahexanoic acid and eicosapentaenoic acid were associated with 11% to 12% reduced risk, and linoleic acid a 19% increased risk, of CRC in the meta‐analysis of combined sexes. In conclusion, this population‐based prospective study and meta‐analysis of cohort studies found little evidence that dietary fatty acid intake was associated with risk of CRC in men.     

Coffee intake and the risk of colorectal adenoma: The colorectal adenoma study in Tokyo

Coffee is a commonly consumed beverage which contains several potential anticarcinogenic and chemopreventive compounds, and has been hypothesized to have protective effects in colorectal neoplasia. However, the limited available data on coffee consumption in relation to colorectal adenoma (CRA), a precursor lesion to most colorectal cancers, remain largely inconsistent. In this study, we evaluated the association of coffee intake with the risk of CRA in a middle‐aged Japanese population. Study subjects were selected from examinees who underwent total colonoscopy as part of a cancer screening program and responded to self‐administered dietary and lifestyle questionnaires. A total of 738 patients with adenoma and 697 controls were included in the study. Coffee intake was assessed with a food frequency questionnaire, and divided into quartiles based on the distribution among controls. Unconditional logistic regression models were used to estimate odds ratio (OR) and 95% confidence interval (CI) of CRA, with adjustment for potential confounding factors. High coffee consumption was associated with a reduced risk of CRA, with a multivariate‐adjusted OR for the highest versus lowest quartile of coffee intake of 0.67 (95% CI = 0.48–0.93; p_trend = 0.02). The inverse association of coffee intake was limited to proximal (OR = 0.64; 95%CI = 0.44–0.95; p_trend = 0.04) and distal colon adenoma (OR = 0.62; 95%CI = 0.39–0.99; p_trend = 0.06), and appeared to be more evident with small (OR = 0.68; 95%CI = 0.49–0.96; p_trend = 0.04) and single adenomas (OR = 0.65; 95%CI = 0.44–0.95; p_trend = 0.02). Green tea intake was not found to be associated with CRA risk. This study provides support for the protective effect of coffee drinking on colon adenomas, a precursor of colon cancer.     

Trends in colorectal cancer incidence in Norway 1962–2006: an interpretation of the temporal patterns by anatomic subsite

There have been rapid increases in the incidence of colorectal cancer in Norway since the 1960s, and rates rank among the highest worldwide. The primary objectives are to describe trends in left‐ and right‐sided colon cancer and rectal cancer by calendar period and birth cohort and to generate hypotheses as to the etiological factors in operation. Although the age‐adjusted incidence rates of both colon and rectal cancer increased in Norway in both sexes up to the 1980s, subsite‐ and age‐specific analyses reveal a deceleration in the rate of increase thereafter, apparent in the rates of both left‐sided colon and rectal cancer. Overall trends in incidence of right‐sided colon cancer continue to increase in both sexes. Rates in both left‐ and right‐sided colon cancers have tended to stabilize or decrease among successive generations born after 1950, however, while incidence rates of rectal cancer appear to be increasing in recent generations. The all‐ages rates are thus in keeping with the commonly reported “left to right shift” of colon cancer, although standardization masks important observations. The cohort patterns provide further evidence that factors earlier in life are important, and while the complex etiology makes interpretation difficult, modifications in diet, obesity and physical activity in Norway are likely among the drivers of the trends in one or more of the colorectal subsites examined. In summary, the recent downturn in the disease at younger ages provides some reason for optimism, although possible increases in rectal cancer among recent birth cohorts are of concern.     

No association between fruit or vegetable consumption and the risk of colorectal cancer in Japan

In a pooled analysis of two prospective studies with 88,658 Japanese men and women, fruit and vegetable consumptions, were not associated with a lower risk of colorectal cancer (705 cases); multivariate relative risk (95% confidence interval) for the highest vs the lowest quartile of intake being 0.92 (0.70-1.19) and 1.00 (0.79-1.27), respectively.     

C-reactive protein and colorectal cancer risk: a systematic review of prospective studies

C-reactive protein is a sensitive but nonspecific systemic marker of inflammation. Several prospective studies have investigated the association of prediagnostic circulating C-reactive protein concentrations with the development of colorectal cancer, but the results have been inconsistent. We performed a systematic review of prospective studies of the association between prediagnostic measurements of circulating high-sensitivity C-reactive protein and development of invasive colorectal cancer. Authors of original studies were contacted to acquire uniform data. We combined relative risks (RR) for colorectal cancer associated with a one unit change in natural logarithm-transformed high-sensitivity C-reactive protein using inverse variance weighted random effects models. We identified eight eligible studies, which included 1,159 colorectal cancer cases and 37,986 controls. The summary RR per one unit change in natural log-transformed high-sensitivity C-reactive protein was 1.12 (95% confidence intervals [CI], 1.01-1.25) for colorectal cancer, 1.13 (95% CI, 1.00-1.27) for colon cancer, and 1.06 (95% CI, 0.86-1.30) for rectal cancer. The association was stronger in men (RR, 1.18; 95% CI, 1.04-1.34) compared to women (RR, 1.09; 95% CI, 0.93-1.27) but this difference was sensitive to the findings from a single study. Prediagnostic high-sensitivity C-reactive protein concentrations were weakly associated with an increased risk for colorectal cancer. More work is needed to understand the extent to which circulating high-sensitivity C-reactive protein or other blood inflammatory markers are related to colonic inflammation.     

Food groups and risk of colorectal cancer

The aim of this systematic review and meta‐analysis was to summarize the evidence on the relationship between intake of 12 major food groups, including whole grains, refined grains, vegetables, fruit, nuts, legumes, eggs, dairy, fish, red meat, processed meat and sugar‐sweetened beverages with risk of colorectal cancer (CRC). We conducted a systematic search in PubMed and Embase for prospective studies investigating the association between these 12 food groups and risk of CRC until April 2017. Summary risk ratios (RRs) and 95% confidence intervals (95% CI) were estimated using a random effects model for high vs. low intake categories, as well as for linear and nonlinear relationships. An inverse association was observed for whole grains (RR_30g/d: 0.95, 95% CI 0.93, 0.97; n = 9 studies), vegetables (RR_100g/d: 0.97, 95% CI 0.96, 0.98; n = 15), fruit (RR_100g/d: 0.97, 95% CI 0.95, 0.99; n = 16) and dairy (RR_200g/d: 0.93, 95% CI 0.91, 0.94; n = 15), while a positive association for red meat (RR_100g/d: 1.12, 95% CI 1.06, 1.19; n = 21) and processed meat (RR_50g/d: 1.17, 95% CI 1.10, 1.23; n = 16), was seen in the linear dose‐response meta‐analysis. Some evidence for nonlinear relationships was observed between vegetables, fruit and dairy and risk of colorectal cancer. Findings of this meta‐analysis showed that a diet characterized by high intake of whole grains, vegetables, fruit and dairy products and low amounts of red meat and processed meat was associated with lower risk of CRC.