MedPage Today -- MONTREAL, May 13 -- Higher serum levels of vitamin D3 were associated with a decreased risk of nonmelanoma skin cancer, researchers reported here. Serum vitamin D3 levels of 30 ng/ml or more were associated with a 45% lower rate of basal cell carcinoma, compared to the rate at the lowest vitamin D3 level, Jean Tang, M.D., from Stanford University Medical Center, reported at the Society for Investigative Dermatology meeting.