Aug. 16, 2011 — -- A new study that links higher vitamin D levels to a higher risk of skin cancer simply emphasizes what doctors have been saying all along: Don't forget the sunscreen.
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Dr. Melody J. Eide and scientists at Henry Ford Hospital in Detroit studied more than 3,200 white participants of a health maintenance organization who were at high risk of developing nonmelanoma skin cancer.
These participants had osteoporosis, a condition in which the bones to become weak and brittle, or worried about possibly being diagnosed with it.
After looking at the patients' levels of vitamin D, which is crucial for good bone health, and their medical histories, the team found that people with higher levels of the vitamin appeared to have a higher risk of developing the two types of nonmelanoma cancer: basal cell, the most common and rarely fatal, and squamous cell.
Dr. Jennifer Stein, an assistant professor at Ronald O. Perelman Department of Dermatology at New York University Langone Medical Center, said the study was valuable because scientists followed a large group of people and because they viewed the patients' medical records and did not have to rely on patients' memories.
She said that although the study did not explore the reasons behind the participants' higher amounts of the vitamin, sunlight exposure was a "very reasonable explanation" and the report provided another piece of evidence linking vitamin D to skin cancer.
Authors of the study noted that "evidence of the association of vitamin D levels with skin cancer has been inconsistent" and that more research was needed. The findings were reported in Archives of Dermatology.
Nonmelanoma is the most common malignant tumor in the U.S. and is diagnosed more than prostate, lung, colorectal, ovarian and breast cancer combined, the study said.
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"Sunlight is one source of vitamin D," Stein said. "We know that sun exposure is definitely related to skin cancer, especially these kinds of skin cancers."
Nearly 37 percent of Americans take vitamin D supplements and Stein said they should not stop because of this study.
"You need healthy amounts of vitamin D," she said. "The safest way to get vitamin D is from your diet rather than from the sun."
More than 2 million cases of nonmelanoma skin cancer are diagnosed in the United States each year, according to the American Cancer Society. Dermatologists diagnose and treat more than 3.5 million cases of skin cancer each year, according to the American Academy of Dermatology. Nearly 20 percent of Americans will develop skin cancer in their lifetime.