Coffee and tea are two very popular beverages. Analysis authors wanted to look at how they relate to head and neck cancer, as research in this area has revealed inconsistent findings.

Researchers used pooled data from the International Head and Neck Cancer Epidemiology Consortium (INHANCE). The analysis included data from 14 individual-level case-control studies, some new and some previously analyzed. Participants provided data via questionnaires to provide information on lifestyle and sociodemographic factors. All the studies included data from participants on coffee and tea consumption, and nine also included information on decaf coffee.

In their statistical analysis, researchers were able to adjust for several factors in their models, including body mass index, age, sex, alcohol use, smoking, and consumption of fruits and vegetables. The analysis also looked at specific types of head and neck cancer.

In all, researchers were able to look at 9,548 cases of head and neck cancer and 15,783 controls. About 93% of participants with head and neck cancer were white, and over 79% of cases were male.

A caffeinated coffee drinking status “was not associated with the risk of HNC” (head and neck cancer) compared to not drinking caffeinated coffee. They also did not identify an association between consuming caffeinated or decaffeinated coffee and the risk of developing laryngeal cancer.

However, researchers did identify a dose-response relationship between drinking caffeinated coffee, head and neck cancer, and all its subsites. Overall, drinking more than four cups of caffeinated coffee daily was associated with a decreased risk.

Drinking more than four cups of caffeinated coffee in a day was associated with a lower risk for head and neck cancer, oral cavity cancer, and oropharyngeal cancers compared to not drinking coffee. Drinking between three and four cups of coffee daily was associated with a lower risk for hypopharyngeal cancer.

The researchers also found that drinking between zero and one cup of decaffeinated coffee daily was associated with a lower chance of developing oral cavity cancer.

Drinking between zero and one cup of tea a day was also associated with a decreased risk for hypopharyngeal cancer and head and neck cancer overall.

The data does have limitations. First, the studies relied on participant reporting, which increases recall bias and misclassification risk.

Missing data is also a factor that limits the findings. Researchers noted that one study did not have data on fruit and vegetable intake, so this data had to be imputed. However, the analysis that did not include this study showed similar results. The data from the studies also did not contain information on components like duration, types of coffee or tea, or beverage temperature.

Another problem is data harmonization. Some studies used ranges for coffee and tea, and others used exact amounts. When comparing the studies with ranges versus exact counts, there were differences in the results for hypopharyngeal cancer and decaf coffee.

Researchers also had to exclude data from some participants. For example, they excluded participants who had cancer in the salivary glands or nasal cavity. Thus, this study did not look at every subtype that is considered part of head and neck cancer. They also excluded participants who had “overlapping head and neck subsites.”

Additionally, aside from one study, the research was from Europe and North America, which limits the generalizability of the results.

This analysis’ findings differ from other data on tea’s protective effects. Researchers acknowledge that the type of tea and study region could be responsible for these inconsistencies. Researchers also note that they weren’t able to distinguish between caffeinated, decaffeinated, and herbal teas. This could be valuable in future research.

Study author Yuan-Chin Amy Lee, PhD, Adjunct Associate Professor with the Huntsman Cancer Institute and School of Medicine at the University of Utah, noted the following to Medical News Today:

“We did not have enough information to assess the temperature of the drinks, any additives to the drinks, how the drinks were prepared, and the specific types. Thus, it would be helpful to investigate whether coffee and tea consumption will have any other side effects or impacts on health overall and to include more details about coffee and tea consumption.”

Overall, the data suggests a distinct benefit to drinking some amounts of coffee and tea. However, it doesn’t mean people should start drastically increasing their consumption.

“The amount of coffee that needs to be consumed for the effect is likely more than is usually consumed in a day. Those sensitive to caffeine will likely have difficulty drinking this much coffee to experience the effect. At the end of the day, this study shows we can still enjoy our coffee in the morning, but we do not have to try and drink more than usual to protect from head and neck cancer,” Kelly noted.

Vivian F. Wu, MD, MPH., ENT-otolaryngologist and Director of the Head and Neck Cancer Center of Excellence at Providence Saint John’s Cancer Institute and Pacific Neuroscience Institute in Santa Monica, CA, who was not involved in the study, noted the following:

“[The study results] indicate that at least four cups of coffee a day are needed to see a benefit. I don’t know about you, but I’m generally bouncing off the walls after four cups of coffee a day. More importantly, caffeine consumption cannot be evaluated within a silo of head and neck cancer. There are likely other health implications of drinking four cups of coffee a day for which I am not the expert. All of this needs to be taken into consideration before any recommendations can be made.”

“Individuals should consult with their doctors before making any decisions on coffee drinking as a preventive measure. Before any health recommendations can be given to the public, it will require a panel of experts in this field to review all the evidence in the research field to date.”
— Yuan-Chin Amy Lee, PhD