There is no question that sun exposure ages the skin and increases risk of skin cancer… but research suggests that we may live longer if we get some sunshine every day.
Dermatologists recommend that our skin should always be protected from the sun. Of course, because they're specialized, most only look at the sun’s effect on the skin rather than its effect on overall health. Although malignant melanoma is a dangerous type of skin cancer, 99% of skin cancers are non-melanoma, and 80% of these are basal cell cancers that are almost never fatal.
But some dermatologists have noticed that their patients with skin cancer are more likely to be in excellent health while those with beautiful skin preserved by avoiding sun were often low-energy and had multiple health problems. This observation motivated Dr. Matt Zirwas, an Ohio dermatologist, to investigate studies that examined this issue. What he found, he says, suggests that completely avoiding sun could have the same effect on your mortality as deciding to smoke a pack of cigarettes a day. Note that an ideal study will always look at increases in overall survival, not just decreased death from one disease.
The science...
A 2014 Swedish study found that the risk of dying from all causes was approximately doubled in those with little or no sun exposure compared to those with the most time in the sun. The main benefit was a decrease in risk of cardiovascular disease – heart attacks and strokes – that reduced risk of death despite an increase in risk of skin cancer. A Denmark study published in 2013 found that people who had been diagnosed with skin cancer actually had lower rates of heart disease and death compared to the general population.
Statistics from US can help us to understand why this could happen. The American Academy of Dermatology estimates that about 7,000 people in US will die of malignant melanoma this year and that less than 5,000 will die of other skin cancers. However, cardiovascular disease kills about 650,000 Americans yearly. It is easy to see that any factor which causes even a modest reduction in cardiovascular disease could quickly outweigh the risk of harm it causes to the skin.
It’s been noted for decades that heart disease increases in the winter and decreases in the summer. This “winter cardiovascular disease phenomenon” could be a result of cold weather causing blood vessels to narrow. But it’s also suspected that the nitric oxide produced by sunshine on the skin could be helping prevent heart disease by dilating blood vessels, lowering blood pressure and keeping arteries smooth and supple. Vitamin D, produced when the sun shines on the skin, is also a factor in promoting health, improving the immune system and reducing heart disease.
Evolution...
We evolved spending a lot of time outdoors in the sun and our skin pigmentation has adapted through evolution to protect us from excessive sun damage. However, when a person with a fair complexion adapted to the north moves to a hot sunny climate, their risk of skin cancer is increased. Those with darker skin adapted to more intense sun are at risk of a lack of vitamin D when they move north. It makes sense that sun precautions should be based on skin type and the climate where the person lives for optimum health and benefit.
But still be cautious!
My motto is “everything in moderation” and this includes sun habits. Considering the benefits of sun exposure as well as the risks, it makes sense to enjoy the sun but avoid sunburn, and to check skin regularly for any sign of possible skin cancer.
The ABCDE rule
Asymmetry – one part of a mole or birthmark doesn’t match the other
Border – the edges are irregular or blurred
Colour – brown, black sometimes with patches of pink, red, white or blue. Not the same all over.
Diameter – larger than 6mm or ¼ inch (about the size of a pencil eraser)
Evolving – the mole is changing in size, shape or colour
Any new spot that is different from others on your body, or is itchy painful, tender, oozing, scaly or bleeding and doesn’t heal, is something to show your doctor.
Check out this article from cancer.org for photos
References: (note that all underlined words are links to websites)
How to Spot Skin Cancer – American Cancer Society
