People who tan are greatly increasing their risk of developing skin cancer. This is especially true if tanning occurs over a period of years because damage to the skin accumulates. Premature aging of the skin (wrinkles) will occur in everyone who is repeatedly exposed to the sun over a long time. Damage may be less apparent and take longer to show up in people with darker skin.If you don't want to get cancer, or premature wrinkles, always wear sunscreen.
Most studies show positive associations with a history of sunburn; however, this association cannot be easily interpreted, because while it might accurately reflect sunburn it could just as well reflect either the tendency to sunburn, if exposed, or intermittent exposure more generally.posted by grouse at 12:55 PM on January 25, 2008
In contrast, the associations with total exposure to the sun over a lifetime or in recent years, as assessed by questionnaire, are inconsistent. This inconsistency may be due to differences in the effects of chronic and intermittent exposure. Chronic exposure, as assessed through occupational exposure, appeared to reduce melanoma risk in three of the large studies, particularly in men; this observation is consistent with the descriptive epidemiology of the condition, which shows lower risks in groups that work outdoors. Several other studies, which were generally smaller or had less detailed methods of exposure assessment, show either no effect or an increased risk associated with occupational exposures.This is referring to the risk of malignant melanoma. It is true that chronic moderate exposure to UV radiation increases the risk of basal and squamous cell carcinomas, but realistically, the skin cancer worth worrying about is melanoma. In this case, there does seem to be a protective effect from chronic moderate exposure to UVR. This is not to say that I think tanning bed sessions before a tropical vacation will confer a significant protective effect, especially for a very fair skinned person. I think I've already made this clear.
5.5 Evaluationposted by [expletive deleted] at 6:39 PM on January 25, 2008
There is sufficient evidence in humans for the carcinogenicity of solar radiation. Solar radiation causes cutaneous malignant melanoma and nonmelanocytic skin cancer.
There is limited evidence in humans for the carcinogenicity of exposure to ultraviolet radiation from sunlamps and sunbeds. [emphasis in original]
On balance, the evidence pertaining to the strength, consistency, dose-response and temporal sequence of the association of the use of indoor tanning equipment with melanoma risk, and of the coherence and biologic plausibility of the association, leads us to conclude that there is convincing evidence to support a causal relationship, particularly with exposure before the age of 35 years.If we approached risk purely by the numbers, we'd tan a lot more often than we got behind the wheel of a car, and roofers would get a lot more respect for putting their ass on the line every day than cops or firemen.
posted by ThePinkSuperhero at 8:34 AM on January 25, 2008 [1 favorite]