Dataset Information

High coffee consumption and different brewing methods in relation to postmenopausal endometrial cancer risk in the Norwegian women and cancer study: a population-based prospective study.

ABSTRACT:

Background

Coffee and its compounds have been proposed to inhibit endometrial carcinogenesis. Studies in the Norwegian population can be especially interesting due to the high coffee consumption and increasing incidence of endometrial cancer in the country.

Methods

A total of 97 926 postmenopausal Norwegian women from the population-based prospective Norwegian Women and Cancer (NOWAC) Study, were included in the present analysis. We evaluated the general association between total coffee consumption and endometrial cancer risk as well as the possible impact of brewing method. Multivariate Cox regression analysis was used to estimate risks, and heterogeneity tests were performed to compare brewing methods.

Results

During an average of 10.9 years of follow-up, 462 incident endometrial cancer cases were identified. After multivariate adjustment, significant risk reduction was found among participants who drank ≥8 cups/day of coffee with a hazard ratio of 0.52 (95% confidence interval, CI 0.34-0.79). However, we did not observe a significant dose-response relationship. No significant heterogeneity in risk was found when comparing filtered and boiled coffee brewing methods. A reduction in endometrial cancer risk was observed in subgroup analyses among participants who drank ≥8 cups/day and had a body mass index ≥25 kg/m2, and in current smokers.

Conclusions

These data suggest that in this population with high coffee consumption, endometrial cancer risk decreases in women consuming ≥8 cups/day, independent of brewing method.

SUBMITTER: Gavrilyuk O

PROVIDER: S-EPMC3986939 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:Coffee consumption has previously been reported to reduce overall and cause-specific mortality. We aimed to further investigate this association by coffee brewing methods and in a population with heavy coffee consumers. The information on total, filtered, instant, and boiled coffee consumption from self-administered questionnaires was available from 117,228 women in the Norwegian Women and Cancer (NOWAC) Study. We used flexible parametric survival models to calculate hazard ratios (HR) and 95% confidence intervals (CI) for all-cause, cardiovascular, and cancer mortality by total coffee consumption and brewing methods, and adjusted for smoking status, number of pack-years, age at smoking initiation, alcohol consumption, body mass index, physical activity, and duration of education. During 3.2 million person-years of follow-up, a total of 16,106 deaths occurred. Compared to light coffee consumers (??1 cup/day), we found a statistically significant inverse association with high-moderate total coffee consumption (more than 4 and up to 6 cups/day, HR 0.89; 95% CI 0.83-0.94) and all-cause mortality. The adverse association between heavy filtered coffee consumption (>?6 cups/day) and all-cause mortality observed in the entire sample (HR 1.09; 95% CI 1.01-1.17) was not found in never smokers (HR 0.85; 95% CI 0.70-1.05). During the follow-up, both high-moderate total and filtered coffee consumption were inversely associated with the risk of cardiovascular mortality (HR 0.79; 95% CI 0.67-0.94; HR 0.80; 95% CI 0.67-0.94, respectively). The association was stronger in the analyses of never smokers (>?6 cups of filtered coffee/day HR 0.20; 95% CI 0.08-0.56). The consumption of more than 6 cups/day of filtered, instant, and coffee overall was found to increase the risk of cancer deaths during the follow-up. However, these associations were not statistically significant in the subgroup analyses of never smokers. The data from the NOWAC study indicate that the consumption of filtered coffee reduces the risk of cardiovascular deaths. The observed adverse association between coffee consumption and cancer mortality is most likely due to residual confounding by smoking.

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