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

Abstract

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 5 0.55), 0.91 (0.56-1.46) for men (p for trend 5 0.53) and 1.16 (0.60-2.23) for women (p for trend 5 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. ' 2006 Wiley-Liss, Inc.Key words: coffee; colorectal cancer; incidence; Japan; prospective study Colorectal cancer is one of the most common cancers worldwide. 1,2 In Japan, colorectal cancer ranks second in terms of agestandardized incidence rate among all cancers, and it is increasing rapidly. 3 Therefore, primary prevention of colorectal cancer worldwide, including Japan, is a considerable public health concern.Coffee is considered to be a protective factor against colorectal cancer through activity of its anticarcinogenic constituents, cafestol and kahweol. 4 It may also decrease the risk of colorectal cancer by reducing the excretion of bile acids and neutral sterols into the colon. 5 Some epidemiological studies have examined the relationship between coffee consumption and the risk of colorectal cancer. 6 Sixteen out of 20 case-control studies supported an inverse association between high coffee consumption and colorectal cancer risk. [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] However, the results of those studies may have been affected by selection bias or recall bias due to retrospective assessment of coffee consumption and other lifestyles-related factors after diagnosis of cancer. In contrast, results from prospective cohort studies have been inconclusive. [27][28][29][30][31][32][33][34][35][36] Among 10 such studies, 1 suggested an increasing risk, 27 3 showed an inverse association 29,34,36 and the others observed no association. 28,[30][31][32][33]35 However, as the studies that observed any association had some statistical l...

Coffee drinking and colorectal cancer risk: an evaluation based on a systematic review and meta-analysis among the Japanese population

“…Five cohort studies (24,25,33,39,40) and nine case-control studies (26)(27)(28)(29)34,35,(41)(42)(43)) met the inclusion criteria. As regards cohort studies (Table 1 and Supplementary Table 1), all reported results for men and women separately (24,25,33,39,40); of these, one additionally reported results for men and women combined (33).…”

“…Two papers presented results on this issue using the same data source (32,33), one reporting incidence and another reporting mortality, and we used incidence data (33). After excluding two casecontrol studies that did not show 95% CI (34,35), we conducted a meta-analysis using random effects model (36) to estimate the summary RR/OR and 95% CI of colorectal cancer for the highest versus lowest category of coffee consumption.…”

Coffee and tea consumption, genotype-basedCYP1A2andNAT2activity and colorectal cancer risk-Results from the EPIC cohort study

“…In general, prospective cohort studies have found no significant associations with either proximal colon, distal colon or rectal cancer. [27][28][29][30][31][32] A recent meta-analysis of cohort studies only found a non-significant reduced colon cancer risk for high coffee consumers. 10 In contrast, a recent prospective cohort study (NIH-AARP Diet and Health study) showed a protective effect of coffee against proximal colon cancer.…”

Food Factors and Oxidative DNA Damage / DNA Repair Systems

“…On the other hand, some studies provided negative conclusions for the effects of coffee consumption on human health. A large cohort study in Sweden and Japan indicated that coffee consumption was not associated with the risk of colorectal cancer [47,48]. Furthermore, another cohort study indicated that coffee consumption increased the risk of certain cancers, such as gastric cancer [49].…”