Visible Light and Melanoma

[Rick Mannix <rcmannix@uci.edu>]

Eric Cowdrey wrote:

I am not aware of any studies suggesting that "visible" radiation was likely
an important carcinogen.
--------------------------------------------

Apparently, such studies have been performed, and at least a weak link
between visible light exposure (generally blue light) and melanoma has been
established. The authors of the article below must have cited some of the
related epidemiological and animal studies they refer to in this abstract
in their paper.


Woodhead, AD; Setlow, RB; Tanaka, M.  Environmental factors in nonmelanoma and
 melanoma skin cancer.

Journal of Epidemiology, 1999 Dec, 9(6
Suppl):S102-14. (UI: 20174134)
Language: English;  Pub type: Review; Review, Academic

Abstract: We discuss the role of sunlight, mostly ultraviolet light (UV),
in the induction of
nonmelanoma and melanoma skin cancer. Whilst the former seems to be
correlated with
accumulated exposure, the causation of melanoma is more complex, and may
also involve the
pattern of, and age at, exposure. The efficacy of sunscreens is debatable;
while they protect
against UVB wavelengths (290-320 nm), and so extend the time that may be
spent in the sun
before becoming sunburnt, their use may subject wearers to excessive
exposure to UVA
(320-400 nm) and visible light. 

Both epidemiological surveys and experiments with animal models
suggest that UVA, and perhaps the visible, may induce melanomas.

Although Japanese have a much lower incidence of skin cancer than
Caucasians, the dramatic rise in skin cancer in Japanese-Americans in
Hawaii exposed to high-intensity irradiation raises concerns. If the
Japanese people adopt sun-seeking behavior, or should the levels of UV
irradiation rise
significantly through depletion of the ozone layer, then this could become
an important health
problem in future.



Rick Mannix
Health Physicist
Laser Safety Officer
University of California
Irvine, CA 92697-2725

949-824-6098
949-824-8539   fax
rcmannix@uci.edu
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