Vitamin D production after UVB: aspects of UV-related and personal factors

During the last decade vitamin D has become a hot topic and our knowledge of its vital role in health and disease is constantly expanding. Solar ultraviolet-B (UVB, 280-320 nm) is both the initiator of vitamin D production in the skin and a risk factor for sunburn and skin carcinogenesis. At present, this dilemma is debated worldwide. In Northern Europe, it is possible to reach a sufficient vitamin D status through sun exposure in the summer months. However, in the winter, the ambient UVB radiation is too low to initiate any production of vitamin D and this has led to a widespread concern and focus on vitamin D status. This review focuses on aspects of UV-related and personal factors of importance for the cutaneous vitamin D production after UVB exposure.