Coffee is a frequently consumed drink that contains a number of antioxidants, polyphenols, and other biologically active compounds that have been shown to have a protective effect against cancer. A number of studies have examined links between coffee consumption and oral cancer producing inconsistent results.

The aim of this review was to evaluate the association between coffee consumption and oral cancer.

Methods

Searches were conducted in PubMed and Embase databases. Two reviewers independently selected studies, abstracted data and assessed study quality using the Newcastle- Ottawa quality (NOS) assessment scale. Studies focusing on the relationship between coffee consumption and the risk of oral cancer, including the oral cavity and the oropharynx but excluding the lip were considered. Data were combined using a random effects meta-analysis

Results

• 15 studies (11 case-controlled, 4 cohort studies) were included.
• 7 were carried out in Europe, 4 in the USA, 2 in Brazil and 3 in Asia
• Meta-analysis of all 15 studies suggest a 37% reduction of oral cancer risk in high coffee drinkers compared with low or no coffee drinkers OR= 0.63 (95%CI; 0.52 – 0.75)
• Similar results were seen for case-controlled studies only OR= 0.60 (95%CI; 0.49 – 0.74)
• and cohort studies only OR= 0.66 (95%CI; 0.45 – 0.98).

Conclusions

The authors concluded

High consumption of coffee can significantly reduce the risk of oral cancer. However, findings of this meta-analysis should be treated with caution because of potential biases and confounders.

Comments

While the authors demonstrate and reduction in oral cancer risk with coffee they are rightly circumspect about there findings. They highlight the retrospective nature of the majority of the included studies with the potential they have for recall bias. The authors also note the lack of detail regarding the coffee consumption (cup size, brewing method, type of bean etc) the individual studies also adjusted for a variable number of potential confounders ranging from 2 -16 which could have implications for their findings. Another recent review by Zhang et al 2015 included 12 studies with also suggested a reduced risk of oral cancer for coffee drinkers [ risk ratio = 0.694 (95% CI; 0.543 – 0.886)]  as did a 2010  by Galeone et al  from the INHANCE consortium.

Links

Primary paper

Li YM, Peng J, Li LZ. Coffee consumption associated with reduced risk of oral cancer: a meta-analysis. Oral Surg Oral Med Oral Pathol Oral Radiol. 2016 Apr;121(4):381-389.e1. doi: 10.1016/j.oooo.2015.12.006. Epub 2016 Jan 4. PubMed PMID: 26972538.

Other references

Zhang Y, Wang X, Cui D. Association between coffee consumption and the risk of oral cancer: a meta-analysis of observational studies. Int J Clin Exp Med. 2015 Jul 15;8(7): 11657-65. eCollection 2015

Galeone C, Tavani A, Pelucchi C, Turati F, Winn DM, Levi F, Yu GP, Morgenstern H, Kelsey K, Dal Maso L, Purdue MP, McClean M, Talamini R, Hayes RB, Franceschi S, Schantz S, Zhang ZF, Ferro G, Chuang SC, Boffetta P, La Vecchia C, Hashibe M. Coffee and tea intake and risk of head and neck cancer: pooled analysis in the international head and neck cancer epidemiology consortium. Cancer Epidemiol Biomarkers Prev. 2010 Jul;19(7):1723-36. doi: 10.1158/1055-9965.EPI-10-0191

INHANCE Consortium publications