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A new study finds that people who drink four or more cups of coffee per day are at least 20 percent, and possibly as much as 32 percent, less likely to develop the sometimes deadly form of skin cancer known as melanoma. Only regular, caffeine-containing coffee confers a cancer-protective benefit. No protection from melanoma was found from drinking decaf.
Little Progress In The Fight Against Melanoma
This study, published in the Journal of National Cancer Institute, answered questions raised by earlier research into the relationship between coffee and skin cancer. There have been about 20 studies that found some kind of protective relationship between drinking coffee and skin cancer, and as many as 1400 studies that found that drinking coffee protects against most kinds of cancer, in general.
Common skin cancers almost never turn malignant and almost never result in death, but once melanoma has become malignant, only about 20 percent of patients live five years or more. Melanoma tends to strike Caucasians who have unusually fair skin. The greatest risk is for those who have fair skin, red hair, and blue eyes. Melanoma rates are highest in Australia and the United States, notably in Hawaii, and about 9000 people worldwide die from the disease in any given year. Melanoma rates have been rising rather than falling, increasing about five to seven percent every year.
Caffeine Is Key To Melanoma Protection
Erikka Loftfield, a doctoral student at the Yale School of Public Health and a fellow at the National Cancer Institute, examined data from a huge study of 447,357 members of the American Association of Retired Persons (AARP), who were tracked for an average of 10 years each. In this group, over the 10 years of the study, there were 1,874 cases of cutaneous melanoma, cancer that has been caught early enough to be survivable, and 2,904 cases of malignant melanoma, which is seldom survivable even with modern treatment.
Participants in the study reported how much coffee they drank, as well as their weight and height for computation of their body mass index (BMI), alcohol intake, and exercise. The study used data from NASA to estimate the amount of UV sunlight exposure for people in the towns in which they lived.
Loftfield analyzed the data and found that:
- Melanoma occurred at an annual rate of 55.9 cases per 100,000 people among those who drank 4 or more cups of coffee per day, and
- Melanoma occurred at an annual rate of 77.6 cases per 100,000 people among those who did not drink coffee.
This study did not find that alcohol consumption, use of sunscreen, or maintaining normal weight protected against this form of skin cancer. It only found a protective effect of coffee for caffeinated coffee, and only for consumption of four cups per day or more. Studies of other kinds of skin cancer have found that caffeine in tea and chocolate also protect against basal cell carcinoma and squamous cell carcinoma, but as yet, the best data is that the caffeine in coffee protects best against melanoma.