Recently, a study in the Journal of Internal Medicine suggested that women who avoid sun exposure are twice as likely to die as compared to those who receive sun exposure. The study attempts to link low vitamin D levels with this increased death rate. However, even the study authors admit that this is speculation on their part.
Encouraging sun exposure to get vitamin D to try to live longer is highly irresponsible. It is a well-established fact that UV radiation from sun or indoor tanning can cause cancer and numerous studies have demonstrated that exposure to UV radiation causes DNA damage in skin cells that can lead to skin cancer (melanoma and non-melanoma). In fact, the National Academy of Sciences Institute of Medicine (IOM) has concluded that while evidence links a person's vitamin D level to their bone health, the evidence linking vitamin D with other health benefits is inconsistent, inconclusive, and insufficient.
Vitamin D can be safely and easily obtained from a healthy diet that includes foods naturally rich in vitamin D, foods/beverages fortified with vitamin D, and/or vitamin D supplemets. Because of the known side effects of UV exposure, vitamin D should not be obtained from unprotected exposure to ultraviolet (UV) radiation.
Source: American Academy of Dermatology