Coffee Drinking and the Risk of Endometrial Cancer: An Updated Meta-Analysis of Observational Studies

ABSTRACT

Background: Several compounds contained in coffee have been found to suppress carcinogenesis in experimental studies. We conducted a dose–response meta-analysis to assess the impact of coffee consumption on the risk of endometrial cancer. Materials and methods: We searched MEDLINE and EMBASE databases for studies published up to August 2016. Using random effects models, we estimated summary relative risks (RR) for cohort studies and odds ratios (OR) for case-control studies with 95% confidence intervals (CI). Dose–response analyses were conducted by using generalized least square trend estimation. Results: We identified 12 cohort studies and 8 case-control studies eligible for inclusion, contributing with 11,663 and 2,746 endometrial cancer cases, respectively. The summary RR for highest compared with lowest coffee intake was 0.74 (95% CI: 0.68–0.81; p_{heterogeneity} = 0.09, I² = 32%). The corresponding summary RR among cohort studies was 0.78 (95% CI: 0.71–0.85; p_{heterogeneity} = 0.14, I² = 31.9%) and 0.63 (95% CI: 0.53–0.76; p_{heterogeneity} = 0.57, I² = 0%) for case-control studies. One-cup increment per day was associated with 3% risk reduction (95% CI: 2–4%) in cohort studies and 12% (95% CI: 5–18%) in case-control studies. After pooling the results from 5 cohort studies, the association remained significant only in women with body mass index over 30 (RR = 0.71, 95% CI: 0.61–0.81). Conclusion: The results from our meta-analysis strengthen the evidence of a protective effect of coffee consumption on the risk of EC and further suggest that increased coffee intake might be particularly beneficial for women with obesity.

Conflict of Interest

The authors have declared no conflicts of interest.

Acknowledgments

The authors thank Dr Kurt Straif for valuable contribution to the manuscript. This study was supported by UiT The Arctic University of Norway and the Norwegian Cancer Society. The funding sources had no involvement in the design and conduct of the study; the collection, management, analysis, or interpretation of the data; the preparation, review, or approval of the manuscript; or the decision to submit the manuscript for publication.

Additional information

Funding

This work builds upon working group deliberations for the IARC Monographs Programme, which is funded by the United States NCI and NIEHS (5U01CA033193) and the European Union (VS/2017/0287).