Vojdeman FJ, et al. - Researchers assessed cancer incidence in relation to serum levels of vitamin D in Danish individuals who had vitamin D levels analyzed at The Copenhagen General Practitioners Laboratory between April 2004 and January 2010. These patients were followed-up until December 31, 2014. Those with pre-existing cancer were not included. The investigators utilized Charlson Comorbidity Index and Cox regression models adjusted for age in one-year intervals, sex, and month of sampling. A median vitamin D level of 46 nmol/L (IQR 27-67 nmol/L) was detected among 217,244 participants. The most frequently occurring cancer was non-melanoma skin cancer, followed by breast, lung, and prostate cancers. Increments of 10 nmol/L vitamin D had no associations with the incidence of breast, colorectal, urinary, ovary or corpus uteri cancer. However, in association with higher levels of vitamin D, higher incidence of non-melanoma and melanoma skin cancer as well as prostate and hematological cancers, but lower incidence of lung cancer, were reported. Vitamin D had no overall protective effect against cancer.