Get outside and get some sunshine!

[ChrisSmolinski]

I just stumbled on this very interesting paper:

The risks and benefits of sun exposure 2016
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5129901/

Some excerpts:

Insufficient sun exposure has become a major public health problem, demanding an immediate change in the current sun-avoidance public health advice. The degree of change needed is small but critically important. The public must be advised to obtain enough sun exposure and vitamin D supplementation to maintain a serum 25(OH)D level of at least 30 ng/mL. Warnings on the dangers of sunburn at any age should be emphasized.

The association between sun exposure and reduced cancer mortality in North America was identified in the 1960s. In the 1980s, it was hypothesized that vitamin D was the protective factor. For most of the intervening years, instead of pursuing further benefits of sun exposure, scientific inquiry focused on the health risks of sun exposure, especially melanoma and other types of skin cancer.

The principal identified non-genetic risk factor is ultraviolet radiation (UVR) exposure, and the relationship between melanoma and UVR is 2-sided: non-burning sun exposure is associated with a reduced risk of melanoma, while sunburns are associated with a doubling of the risk of melanoma. It has long been observed that outdoor workers have a lower incidence of melanoma than indoor workers.

A more plausible explanation for the rise in melanoma incidence since 1935 may be the continually-increasing insufficient non-burning sun exposure and related increasing vitamin D deficiency/insufficiency, and the increasing sunburn prevalence experienced by the American public over the same time period. We can find no consistent evidence that use of chemical sunscreens reduces the risk of melanoma. Sunscreens do, however, reduce acclimatization to UVR and vitamin D production in the skin. Labeling should also state that sunscreens have not been shown to be effective in reducing the risk of melanoma.

[Charlie_Dont_Surf]

The principal identified non-genetic risk factor is ultraviolet radiation (UVR) exposure, and the relationship between melanoma and UVR is 2-sided: non-burning sun exposure is associated with a reduced risk of melanoma, while sunburns are associated with a doubling of the risk of melanoma. It has long been observed that outdoor workers have a lower incidence of melanoma than indoor workers.

This is what I have been thinking but never got around to look into. Some exposure is necessary for Vitamin D production and to acclimate. As the body acclimates, the threshold of exposure that presents a danger will increase. Too much exposure is always too much, but the threshold of what is too much is individual and varies with time.

A more plausible explanation for the rise in melanoma incidence since 1935 may be the continually-increasing insufficient non-burning sun exposure and related increasing vitamin D deficiency/insufficiency, and the increasing sunburn prevalence experienced by the American public over the same time period. We can find no consistent evidence that use of chemical sunscreens reduces the risk of melanoma. Sunscreens do, however, reduce acclimatization to UVR and vitamin D production in the skin. Labeling should also state that sunscreens have not been shown to be effective in reducing the risk of melanoma.

That's very interesting.