Coffee is a commonly consumed hot drink that is known to contain biologically active compounds that have demonstrated protective effects against cancer. A number of studies and reviews have looked at the potential associations between coffee consumption and the risk of oral cavity cancer.
The aim of this review was to assess the association between coffee intake and the risk of oral cancer.
Methods
Searches were conducted in the PubMed, Embase and Cochrane Library databases with no restrictions on language. Cohort or case-controlled studies assessing the relationship between coffee intake and the risk of oral cancer were considered. Two reviewers independently searched the literature, selected studies, extracted data and assessed study quality. The Newcastle-Ottawa Scale (NOS) was used to assess study quality.
The association between coffee intake and the risk of oral cavity cancer in each individual study was obtained as odds ratio (OR) and its corresponding 95% confidence intervals (CI) and meta-analysis conducted. Sensitivity analysis for high or intermediate versus low coffee intake and additional subgroup analysis were also undertaken.
Results
- 19 studies (5 cohort, 14 case-control) studies involving a total of 6456 patients were included.
- 15 studies reported on the incidence of oral and pharyngeal cancer with 4 reporting on oral cavity cancer.
- Four studies had 8 stars on NOS, the had 7 and 5 six stars, the remainder had 5 stars.
- High coffee intake was found to be associated with a reduced risk of oral cavity cancer compared with the lowest category of coffee intake: –
- OR= 0.68 (95%CI; 0.56–0.82) [ all 19 studies].
- OR= 0.70 (95%CI; 0.55–0.90) [14 case-control studies].
- OR= 0.65 (95%CI; 0.48–0.87) [ 5 cohort studies].
- intermediate coffee intake was also associated with a significantly lower risk of oral cavity cancer overall and in the case-controlled studies but not in cohort studies.
- OR= 0.85 (95%CI; 0.77–0.94) [ all 18 studies].
- OR= 0.86 (95%CI; 0.76–0.98) [13 case-control studies].
- OR= 0.83 (95%CI; 0.48–1.02) [ 5 cohort studies].
Conclusions
The authors concluded: –
The findings of this meta-analysis indicate that high or intermediate versus low coffee intake might be associated with a reduced risk of oral cavity cancer irrespective of the study design (case–control or cohort study). However, these need to be validated in further large-scale prospective cohort studies.
Comments
We last looked at a review of the link between coffee intake and the risk of oral cancer back in 2016 (Dental Elf – 17th Mar 2016). This new review includes all the studies in included in the earlier review with the addition of 2 more studies. Consequently, the ORs demonstrating a reduced risk of oral cavity cancer with high coffee consumptions are very similar. While this new review suggests that a risk lowering effect also occurs with intermediate levels of coffee consumption this should be viewed very cautiously as this is not seen when only the cohort studies are considered.
A majority of the studies used structured questionnaire to collect data there were sometimes self-administered with a smaller number of studies using a standardised interview. As a majority of the studies are retrospective the issue of recall bias may be a factor and while all of the studies included smoking as a possible confounder not all included alcohol, the overall number of potential confounders considered also varied from study to study.
Links
Primary Paper
He T, Guo X, Li X, Liao C, Yin W. Association between coffee intake and the risk of oral cavity cancer: a meta-analysis of observational studies. Eur J Cancer Prev. 2019 Apr 23. doi: 10.1097/CEJ.0000000000000515. [Epub ahead of print] PubMed PMID: 31021885.
Other references
Dental Elf – 17th Mar 2016
