A new study finds that drinking four or more cups of coffee a day is linked to reducing the risk of the most deadly form of skin cancer.

Melanoma, the fifth most common form of cancer in the United States, is the leading cause of skin cancer-related deaths, Forbes reports. Over 70,000 people are diagnosed with melanoma each year, and close to 10,000 people die from it.

For the study published in the Journal of the National Cancer Institute, researchers tested over 447,000 people between the ages of 50 and 71 who did not have cancer at the start of the research. Scientists studied participants for over 10 years and found that 900 of them were diagnosed with melanoma, while 1,900 developed another form of skin cancer.

The participants who drank more than four cups of coffee a day were had a 20 percent lower risk of developing the deadly form of skin cancer.

Coffee compounds have been shown to suppress the formation of cancer, reduce oxidative stress and DNA damage in cells in mice and skin cell cultures, but the new study produced mixed results for humans. One component of the study found a link between coffee drinking and reduced skin cancer in women but not in men. Another component found no connection to melanoma but to basal cell carcinoma.

The authors of the study frequently adjusted factors that might influence skin cancer including ultraviolet radiation exposure, body mass index, age, smoking history and alcohol consumption, CBS News reported.

"Because of its high disease burden, lifestyle modifications with even modest protective effects may have a meaningful impact on melanoma morbidity," the researchers said about their findings' possibility of being applicable to other populations.

Previous studies have linked regular coffee consumption with reducing the risk of other serious diseases like diabetes, depression, Alzheimer's disease and Parkinson's disease. The connection between coffee and skin cancer has not been so clear-cut in human studies.