Do You Live In The Skin Cancer Capital Of The World? | Skin Types and UV Exposure
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Welcome to Queensland in Australia, the Sunshine State. It’s known for it’s amazing beaches, warm sunny weather and the Great Barrier Reef.
But did you know that Queensland also has the highest rate of melanoma anywhere in the world!
But what is it about Queensland that’s so special? I mean there are lots of other places with lots of sunshine. I decided to find out!
Rates of melanoma (incidence)
Of the common types of skin cancer, melanoma is by far the deadliest. When I looked at the rate of new melanoma diagnoses, I was shocked to find that Queensland is well and truly at the top of the league table. The rate of melanoma is triple that of North America. But why?
Well we know that sunburns are responsible for 95% of melanomas, and we know that sunburns are caused by excessive UV or Ultraviolet light.
Let’s take a quick look at UV.
Ultraviolent (UV) light and skin cancer
UV light is just another part of the electromagnetic spectrum. UV light has slightly higher energy than visible light.
Visible light is reflected off your skin but the higher energy level of UV means that it can penetrate into the skin layers. UV is a natural part of our environment, so the skin can handle a certain amount of UV. In fact, a moderate amount of UV can be beneficial. However if skin cells are exposed to excessive UV, there can be DNA damage, which can lead to skin cancer down the track.
Now there are a couple of important things that influence the risk of skin cancer: the first is how resilient your skin is to UV light and the second is the amount of UV exposure that you’ve had in your lifetime.
Skin types and the Fitzpatrick scale
Resilience of the skin is related to your skin type, which is based on your genetics. It’s pretty straightforward, people with fair skin tend to be very UV sensitive and people with darker skin tend to be very UV resilient.
A US study compared the rate of melanoma diagnosis in different ethnic groups. They categorised people into “Whites, Hispanics, American Indians, Asian and African Americans”. As you can see the rate is much higher in those people classified as “White”
In fact, there is a scale that doctors use to estimate how sensitive someone’s skin is to UV light and this is called the Fitzpatrick scale.
Type I describes people with incredibly fair skin who burn very easily. Type VI is the other extreme – it describes people with very dark skin who are most resilient to UV damage.
Variations in UV exposure
Okay so now we’ve discuss skin types, let’s talk about differences in UV exposure. Did you know that where you live in the world has an influence on the amount of UV that you are exposed to?
This is a map that shows the average UV index in different parts of the world. Red shows high average UV, Yellow is medium and green is low.
What you’ll notice is that countries around the equator have the highest average UV radiation levels. This includes places like Australia, Malaysia, Central Africa and parts of South America.
This should mean that all of these countries should have really high rates of melanoma right? Well it’s not that simple.
It goes back to the majority skin type of the people living in those areas. Let’s take a look at a few examples:
In Malaysia the UV index averages between 12-14. However the average skin type tends to be Fitzpatrick three to five. Let’s take a look at Brazil. Here the skin type for most people is also three to five (Ronaldo). Next, Kenya where the skin type for most people is five to six. All of these countries have very high UV exposure, but most of the people who live there also have UV resilient skin types.
Why is Queensland the skin cancer capital?
Something very interesting happens when you look at Australia and New Zealand – the most common skin type ranges from type one to three. This means that a large number of people living these areas are highly sensitive to UV damage.
Let’s put this all together – Queensland is close to the equator so there is high UV radiation levels. Add to this the fact that most people living in Australia and New Zealand tend to have fair skin. Also no other country that close to the equator has such a large proportion of people with fair skin. It’s no wonder Queensland has the highest rate of skin cancer in the world!
But there’s something else that I haven’t mentioned yet – and that is that Australians and New Zealanders love the outdoors. Tanning has been part of our culture since the 1950s. This is in contrast to south east Asian countries where people tend to avoid the sun because people want a fair complexion.
So what does this mean for all of us. Well the first thing is that skin cancer is not as simple as having fair skin – it also depends where in the world you live. But since you can’t change where you live that easily, sun protection becomes your best friend, especially if you have fair skin.
But what is good sun protection? Is your sunscreen protecting you from all the different types of UV?
If you’re interested in knowing the answer to these questions, let me know in the comments below and subscribe so you won’t miss it.
Thanks for watching and I’ll see you in the next one.
Vector maps: http://freevectormaps.com
Lupita Nyong’o: Gage Skidmore
Reef tan advertisement: http://glossysheen.blogspot.com/2013/01/reef-tan-advertisement-dolly-december.html
Karimkhani et. Al 2015: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5575560/
Aitken et.al 2018: https://www.ncbi.nlm.nih.gov/pubmed/29105744
Sunburn causes 95% of melanomas: https://www.cancer.org.au/about-cancer/types-of-cancer/skin-cancer.html
Cormier et. Al 2006: https://www.ncbi.nlm.nih.gov/pubmed/17000949