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The skin cancer epidemic is not being driven by sunlight

December 7, 2019


Hello. I’m Dr. Karen with Embrace Life Om and Mother
Corps and in today’s video I’m going to be talking about the real cause of the skin cancer
epidemic. This is part of a continuing series on Light
and Your Health, and in order to better understand today’s video we highly recommend that you
watch Part 3 in our series, The Hidden Hazards of Energy-Efficient lightbulbs. There are three main types of skin cancer:
squamous cell carcinoma, basal cell carcinoma, and malignant melanoma. Of these three basal cell and squamous cell
carcinomas are very common, but usually limited to the skin and are rarely fatal. Malignant melanoma is often limited to the
skin as well but can be invasive and is the leading cause of skin cancer related deaths. All types of skin cancer have increased in
number dramatically over the last 80 years. For example, with malignant melanoma between
1950 and 2007 the incidence in woman increased by a factor of 9 and the incidence in men
increased by a factor of 17. To avoid being caught up in this skin cancer
epidemic we were often given the advice to avoid exposure to the sun, but the data shows
that the only cancer which can be related to cumulative sun exposure is squamous cell
carcinoma, while the incidence of basal cell and malignant melanoma actually decreases
with cumulative sun exposure. So yes, getting a lot of sun exposure throughout
your lifetime is correlated with a decreased risk of malignant melanoma and is also correlated
with a decreased risk of many other cancers. For example, getting a lot of sun is associated
with a whopping 80 to 90 percent decrease in breast and colon cancer mortality. So for every one cancer death from squamous
cell carcinoma that might be averted by avoiding the sun, there are at least 30 deaths that
could be averted by engaging in regular sunning. Not only that, but the sunblock lotion that
were repeatedly urged to use to avoid the cancer may avoid squamous cell carcinoma but
may actually increase your risk for malignant melanoma and other cancers. In order to understand what I just told you
about skin cancer, we need to understand the very different effects of different frequencies
of light on the skin. So the different frequencies that are important
in this story are the three ultraviolet or UV frequencies which in order of increasing
energy are UVA, UVB, and UVC; the visible frequencies violet, blue, and red, and the
frequency which is below the visible range, infrared. Now UVA, violet, and blue light are each important
for your health in different ways, however for reasons that are too complicated to explain
here, the net effect of exposure to these light frequencies is increased oxidative stress
in yourself, and malignant melanoma is a cancer whose growth is encouraged by increased oxidative
stress. Now the original sun blocks only blocked UVB
light. This would protect you against sunburn, however
it would also prevent you from getting the antioxidants of UVB exposure so you would
stay in the Sun longer feeling that you were protected, meanwhile receiving heavy oxidative
stress from all the UVA, blue, and violet light that was not being blocked. Today’s sunblocks tend to protect against
UVA as well as UVB but you’re still blocking your benefits from the UVB while still receiving
oxidative stress from the unbalanced blue and violet light, so the widespread use of
sunblock lotions explains some of the increase in skin cancer, but it probably explains less
than five to ten percent of the increase. Tanning beds are a serious problem because
they give you a high dose of the oxidative UVA radiation while not giving you the protective
UVB, but there are many people getting skin cancer who have never used a tanning salon. The increased solar radiation from the depletion
of the ozone layer likewise does not explain the vastness of the increase in skin cancer. Some of the other increase in skin cancers
can be related to chemical exposure such as herbicides and pesticides, to taking medications
which photosensitize the skin and to the increase in systemic diseases that cause oxidative
stress such as irritable bowel disease and type 2 diabetes. However there’s still a lot of skin cancers
that remain unexplained. It was long recognized that the skin cancer
epidemic was basically occurring only among those who work indoors, and it was hypothesized
that indoor workers would get more severe sunburns when they went out on vacation, and
indeed the number of sunburns is correlated with an increased risk of malignant melanoma,
however it was later shown that this is a correlation and not a causation. People who have skin types that predispose
them to sunburn also have skins which are less resistant to oxidative stress, so while
people who are sunburned more do get more melanoma it is not necessarily a causative
relationship. Beral et al. in 1982 explored the hypothesis
that it wasn’t something outside that was causing the melanoma in the indoor workers
but something inside. They looked at workplaces with fluorescent
lighting installed, and found that women in those workplaces had double the risk of getting
malignant melanoma and men had quadrupled the risk. Future studies have supported the hypothesis
that it is actually fluorescent light bulbs that is the main cause of the skin cancer
epidemic. The reason why fluorescent light bulbs just
cause skin cancer and other skin disorders is the nature of the light spectra produced. Unlike the full broad spectrum light spectra
produced by the sun the light coming out of a fluorescent bulb is very concentrated and
narrow wavelengths. Some of these light concentrations in the
range of UVC, UVA, and visible violet light. The exact wavelengths of UVA and violet light
at which the fluorescent light bulbs have a strong peak have been shown to be the same
wavelengths that are extremely carcinogenic in laboratory animals. In addition to having this very concentrated
light in the wavelengths that are dangerous to human cells the fluorescent light is lacking
the UVB and more importantly the infrared light which is strongly anti-oxidative. So taken as a whole, the fluorescent light
creates a lot of oxidative stress on skin cells while not giving them the light they
need to relieve that stress. Now to be fair, the light bulb is coated with
materials to try to block the escape of the UV rays, but experiments have shown that the
UV rays are not completely blocked, and that a significant amount of them do escape. And there is no attempt to block the escape
of the violet light. Temporal data strongly supports the fluorescent
lighting hypothesis. Fluorescent lights were first introduced for
commercial use in 1939 and skin cancer rates began increasing in 1940. During the 1940s most of the fluorescent lights
were used in the in factories in the defense industry which at the time had a large number
of women workers, and by 1950 most of the melanoma cases were in women a trend which
later significantly reversed. And then there’s the birth cohort observation. For people born before World War II, the year
of birth is a powerful independent predictor of whether they will get malignant melanoma
with earlier birth years corresponding to a lower chance of contracting the disease. After 1950 the year of birth makes much less
difference in total risk. We can understand this by noting that before
1940 there was no widespread use of fluorescent lighting so someone born in 1935 for example
would have a whole five years of their life with no fluorescent lighting exposure, whereas
someone born 1930 would have a full 10 years of their life with no exposure to fluorescent
lights. So the more years of your life that you have
no fluorescent lighting, the lower your lifetime risk of contracting malignant melanoma. On the other hand if you’re born after 1950,
you have no years of not experiencing fluorescent lighting and you’ll probably have experienced
a lot of fluorescent lighting in your classroom. So everyone born after 1950 has a more uniform
but elevated risk. So what to do if you want to decrease your
risk of skin cancer? Number one get into the sun. The sunlight will give you vitamin D and will
also reduce your total oxidative stress, but that is if you get all of the sunlight. If you don’t get the UVB, the effect will
not be sufficiently powerful. So get rid of the sunscreen. When you’ve reached the point where you’re
going to burn, cover up with a shirt and hat and get in the shade, Number two, remove fluorescent
lights and high color temperature LED lights from your home and workplace. High color temperature LED lights have a lot
of blue light and since blue light is oxidative those lights are also likely to cause skin
cancer. To find out what light bulbs to replace with
please watch Part 2 light bulbs, in this series. If you’re working indoors use as much direct
solar light as you can, and also if you can open the windows, because the glass pane will
block the UVB that you need to balance the UVA, violet, and blue light. If you can’t avoid exposure to fluorescent
or high color temperature LED lights or if you’ve already had a lot of such exposure
in your life, then you might consider adding a little bit of UVB light lamp therapy and
also adding infrared light therapy. You could do this every day that you’re being
exposed to the fluorescent lighting. We’re going to be doing a couple of more shows
on cancer, but after that we’ll do a series of shows dedicated to using infrared therapy. Thank you so much for watching today.

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