Keep in mind too that Vit. D overdose that comes from exposure to sunlight is impossible and that concerns about melanoma may be misplaced--e.g., rather than due to increased exposure to sunlight, reported increases in melanoma may as likely be due to decreased exposure.
In addition, it is reported that increased reporting of melanoma skin cancer may actually be due to, "an artifact caused by diagnostic drift" --
https://www.ncbi.nlm.nih.gov/pubmed/19519827
CONCLUSIONS:
We therefore conclude that the large increase in reported incidence is likely to be due to diagnostic drift which classifies benign lesions as stage 1 melanoma. This conclusion could be confirmed by direct histological comparison of contemporary and past histological samples. The distribution of the lesions reported did not correspond to the sites of lesions caused by solar exposure. These findings should lead to a reconsideration of the treatment of 'early' lesions, a search for better diagnostic methods to distinguish them from truly malignant melanomas, re-evaluation of the role of ultraviolet radiation and recommendations for protection from it, as well as the need for a new direction in the search for the cause of melanoma [Br J Dermatol. 2010]
In addition to skewing disease rates as a result of the misdiagnosis on non-cancerous lesions, there also is evidence that the sites and distributions of lesions diagnosed as melanoma many times do not correspond to exposure to sunlight being the primary cause.