Avoidance of sun exposure as a risk factor for major causes of death: a competing risk analysis of the Melanoma in Southern Sweden cohort.
Does the sun cause cancer? How much sun should I get? Old dogma is being challenged. This study says more than less.
Let me preface this post by saying that I'm a big proponent of reasonable sun exposure. Burning is clearly bad for a number of reasons, but more and more evidence is pointing toward our relationship with the sun is a vital component of optimal health. Did you know that the original studies that pointed toward UV light causing cancer were done in a laboratory with artificial lights? The sun contains a wide array of frequencies from UV to infrared that have a balancing and systemic effect on the body. Isolating UV light is like doing study on the health effects of potatoes and only serving someone the skins. The study linked is epidemiological study, which means its a survey of people in real life reporting on their sun exposure habits over many years. While epidemiological rarely elucidate the mechanisms for why things occur, they can be powerful tools for understanding trends and correlations.
This post goes over some of the findings of the study, and future posts will talk more in depth about the physiological mechanisms of sunlight interaction. We evolved on earth under the sun, and our bodies are exquisitely tuned to respond to sunlight. I'll leave this picture here below (courtesy of Jack Kruse) to give you clue where this information is headed.
Anyway, on to the study.
This longitudinal (long term) study of close to 30,000 Swedish women showed that active sun exposure habits were related to longer life span. Heart disease was significantly lower in the active sun exposure group. The data shows that while skin cancer rates were higher in the active sun exposure group it was largely because that group lived longer and got cancers as they aged, however the outcome for those cancers were better in the sun exposure group:
"As a result of their increased survival, the relative contribution of cancer death increased in these women."
"Nonsmokers who avoided sun exposure had a life expectancy similar to smokers in the highest sun exposure group, indicating that avoidance of sun exposure is a risk factor for death of a similar magnitude as smoking."
"Compared to the highest sun exposure group, life expectancy of avoiders of sun exposure was reduced by 0.6-2.1 years."
And from this study: https://www.ncbi.nlm.nih.gov/pubmed/26049767
Risks and benefits of UV radiation in older people: More of a friend than a foe?
"Intermittent sun exposure is a risk factor for the more dangerous melanoma but chronic sun exposure and outdoor occupation may be protective."
There's more to the story than UV radiation, there are numerous system health benefits to regular sun exposure which I'll into more detail on another post.
Go get some sun!
