Recent headlines have trumpeted an association between drinking coffee and protection against melanoma as “good news for coffee drinkers.” The results have been touted as “another excuse” to indulge in the world’s favorite pick-me-up, and add to a growing body of research suggesting that numerous compounds are present in coffee that promote health and prevent cancer.
However, as with most dietary research, it’s difficult to link exposure to a single factor, such a coffee, with a health benefit, such as reduced melanoma risk, without considering the influence of a full spectrum of lifestyle and environmental factors.
Curb your enthusiasm
Researchers try to adjust their data to account for these “confounding factors,” but until further research can prove that drinking coffee does indeed reduce the risk of melanoma by showing exactly how it does, this good news for coffee drinkers should be regarded as nothing more than an interesting possibility for the time being.
Establishing the link
For the study, published in the Journal of the National Cancer Institute, researchers from the institute and Yale School of Public Health analyzed data collected by the U.S. National Institutes of Health and AARP. From a food frequency questionnaire sent to 3.5 million AARP members, the researchers focused on coffee drinking reported by 444, 357 white seniors. The study focused on Caucasians because of the higher melanoma risk among this population compared to other races.
The incidence of melanoma among respondents was tracked for an average 10.5 years. A statistical analysis showed that caffeinated coffee drinkers (not decaffeinated coffee drinkers) were less likely to develop malignant melanoma. The protective effect of coffee drinking also increased with the level of consumption. However, the association was found only with malignant melanoma, not melanoma in situ, which means a cancer lesion that remains confined to a specific site on the skin and has not yet metastasized.
The researchers adjusted the data to account for other factors, such as body mass index, alcohol use, smoking and ultraviolet radiation exposure and the protective effect of coffee was still evident. But closer examination suggests the influence of these confounding factors was not completely accounted for.
For example, to determine rates of UV exposure, researchers relied on a comparison of average levels of UV radiation in the zip codes of respondents, not reported individual levels of UV exposure. What’s more, it could be possible that people who drink more coffee tend to spend a lot more time indoors working in offices than people who drink less.
Don’t forget the sunscreen
The researchers conceded that the results of their study cannot be applied to populations other than Caucasian seniors in the U.S. They also noted that their results will have to be replicated in further studies before you can increase your coffee intake with the confidence that you’re protecting yourself from melanoma, the deadliest form of skin cancer.
Looking on this research with a skeptical eye doesn’t mean coffee won’t protect you from skin cancer. Yet until a direct cause and effect is established, continue to enjoy your coffee, but don’t forget the sunscreen.
Journal of the National Cancer Institute
Medical News Today