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Coffee and cancer risk: A meta-analysis of prospective observational studies

View Article: PubMed Central - PubMed

ABSTRACT

Meta-analyses on coffee and cancer incidence mainly restricted to limited cancers. We carried out a more comprehensive meta-analysis of cohort studies to explore association between coffee and most cancer types. We conducted comprehensive search and summarized relative risk (RR) and 95% confidence intervals for the highest versus lowest coffee intake and cancer using STATA12. We conducted dose-analysis if result suggested significant association. The publication bias was evaluated with begg’s and egger’s test. Finally, 105 individual prospective studies were included. Inverse associations were observed on oral, pharyngeal, colon, liver, prostate, endometrial cancer and melanoma, with RR 0.69 (95% CI = 0.48–0.99, I2 = 73.4%, P = 0.044), 0.87 (95% CI = 0.78–0.96, I2 = 28.4%, P = 0.007), 0.46 (95% CI = 0.37–0.57, I2 = 0%, P = 0), 0.89 (95% CI = 0.84–0.93, I2 = 30.3%, P = 0.003), 0.73 (95% CI = 0.67–0.80, I2  = 0%, P = 0) and 0.89 (95% CI = 0.80–0.99, I2  = 0%, P = 0.031) respectively. However, the relative risk for lung cancer is 2.18 (95% CI = 1.26–3.75, I2  = 63.3%, P = 0.005). The summary relative risk for increment of 2 cups of coffee were RR = 0.73, 95% CI = 0.67–0.79 for liver cancer, RR = 0.97, 95% CI = 0.96–0.98 for prostate cancer and RR = 0.88, 95% CI = 0.85–0.92 for endometrial cancer. Accordingly, coffee intake was associated with reduced risk of oral, pharynx, liver, colon, prostate, endometrial cancer and melanoma and increased lung cancer risk.

No MeSH data available.


Flowchart of the searching and review of literatures.
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f1: Flowchart of the searching and review of literatures.

Mentions: We conducted a computerized search of the literature on coffee and cancer from inception to July 2015. The search terms were (cancer OR tumor OR carcinoma) AND (coffee OR caffeine OR beverages OR diet OR drinking). Three major electronic databases (PubMed, EMBASE, and The Cochrane Library) were used to search the relevant literature without language restriction. Then, we classified these studies into different groups according to cancer type and conducted repeated searches. Finally, we obtained a relatively complete literature record for every type of cancer. Moreover, we reviewed the references from retrieved articles for additional studies (Fig. 1).


Coffee and cancer risk: A meta-analysis of prospective observational studies
Flowchart of the searching and review of literatures.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5036059&req=5

f1: Flowchart of the searching and review of literatures.
Mentions: We conducted a computerized search of the literature on coffee and cancer from inception to July 2015. The search terms were (cancer OR tumor OR carcinoma) AND (coffee OR caffeine OR beverages OR diet OR drinking). Three major electronic databases (PubMed, EMBASE, and The Cochrane Library) were used to search the relevant literature without language restriction. Then, we classified these studies into different groups according to cancer type and conducted repeated searches. Finally, we obtained a relatively complete literature record for every type of cancer. Moreover, we reviewed the references from retrieved articles for additional studies (Fig. 1).

View Article: PubMed Central - PubMed

ABSTRACT

Meta-analyses on coffee and cancer incidence mainly restricted to limited cancers. We carried out a more comprehensive meta-analysis of cohort studies to explore association between coffee and most cancer types. We conducted comprehensive search and summarized relative risk (RR) and 95% confidence intervals for the highest versus lowest coffee intake and cancer using STATA12. We conducted dose-analysis if result suggested significant association. The publication bias was evaluated with begg’s and egger’s test. Finally, 105 individual prospective studies were included. Inverse associations were observed on oral, pharyngeal, colon, liver, prostate, endometrial cancer and melanoma, with RR 0.69 (95% CI = 0.48–0.99, I2 = 73.4%, P = 0.044), 0.87 (95% CI = 0.78–0.96, I2 = 28.4%, P = 0.007), 0.46 (95% CI = 0.37–0.57, I2 = 0%, P = 0), 0.89 (95% CI = 0.84–0.93, I2 = 30.3%, P = 0.003), 0.73 (95% CI = 0.67–0.80, I2  = 0%, P = 0) and 0.89 (95% CI = 0.80–0.99, I2  = 0%, P = 0.031) respectively. However, the relative risk for lung cancer is 2.18 (95% CI = 1.26–3.75, I2  = 63.3%, P = 0.005). The summary relative risk for increment of 2 cups of coffee were RR = 0.73, 95% CI = 0.67–0.79 for liver cancer, RR = 0.97, 95% CI = 0.96–0.98 for prostate cancer and RR = 0.88, 95% CI = 0.85–0.92 for endometrial cancer. Accordingly, coffee intake was associated with reduced risk of oral, pharynx, liver, colon, prostate, endometrial cancer and melanoma and increased lung cancer risk.

No MeSH data available.