By: Dr. John Bagnulo, Director of Nutrition
"Reality is an illusion, albeit a persistent one" -- Albert Einstein
The last 30 years have seen an exponential increase (more than 300% by conservative estimates) in the rate of malignant melanoma incidence. By now, most Americans think of direct sunlight as a risk factor for not only wrinkles and skin cancer, but for premature death. To question any of these associations seems almost absurd and similar to questioning the role of smoking cigarettes with respect to developing lung cancer. And let’s be clear, the majority of dermatologists I interviewed for this article do in fact consider sun exposure a health hazard – unquestionably, in their own words. But there is a steady stream of research in the area of malignant melanoma epidemiology that raises more than just a few interesting questions. In fact, after looking very closely at over 40 papers on this topic, written over the past 10 years, it appears that the association between sunlight and malignant melanoma is possibly an inverse relationship more than it is a causal one.
Of course there are many levels to this story, the first of which is misdiagnosis. Recent research in the UK showed that a large percentage of malignant melanoma diagnoses were not stage 1 melanomas but were actually other forms of benign skin growths, or were basal or squamous cell cancers (which are generally non-invasive and not lethal forms of skin cancer as malignant melanomas are). In this investigation, the authors conclude "the large increase in reported incidence is likely to be due to diagnostic drift which classifies benign lesions as stage 1 melanoma. This conclusion could be confirmed by direct histological comparison of contemporary and past histological samples. The distribution of the lesions reported did not correspond to the sites of lesions caused by solar exposure." (1)
If this is in fact the case, then numerous other questions become increasingly important. Such as, why do so many individuals develop "skin cancer" (i.e. malignant melanomas) on areas of their body that never get sun exposure? Why has the widespread use of sunscreen and sunblock not decreased the incidence of skin cancer or malignant melanoma? And, maybe most importantly, why do individuals with the most sun exposure have the lowest risk of malignant melanoma when compared to those individuals who have the least sun exposure? (2,3)
Even more contrary to public opinion, is the research that shows steady, linear, dose-dependent, decreased risk for all-cause mortality with greater and greater sun exposure. Simply stated, skin cancer or no skin cancer, in every investigation to date, populations, regardless of skin color and where they live, live longer with more time out in the sun when compared to those who spend less time in the sun.
Now if you have avoided the sun for most of your life as directed by either a public health message or your hair stylist, I would expect one of three typical reactions: disbelief, anger, or curiosity, and sometimes a combination of all three. Revelations like getting more time in the sun are hard to accept when our lifestyle is significantly shaped around the message to avoid the sun.
During the process of earning a Masters of Public Health, I realized that there are numerous precedents where public health messages were constructed on less-than-safe foundations of well-designed or interpreted research. The intentions may have been honorable but the actual advice did not serve the public well. There was a time when young women were encouraged to bottle feed as opposed to breast feed and there was a time when municipalities embarked on DDT treatment of neighborhoods to reduce mosquito populations…the list goes on.
Several dermatologists and researchers are becoming more outspoken and more determined to share their research with the community. One of these experts is Dr. Sam Shuster, a dermatologist and honorary consultant at Norfolk and Norwich University Hospital in the UK. In a recent interview with Huffington Post, Dr. Shuster shared his assessment, "All the scriptures about sun exposure and melanoma are premature. The UV explanation for melanoma is not adequate."
As evidence, Shuster went on to say, "Melanoma cases occur on relatively unexposed sites of the body, especially the feet of dark-skinned Africans. There is no evidence that melanomas occur at sunburn sites on the body. Meanwhile, it’s difficult to create melanomas in laboratory experiments with ultraviolet light, suggesting that UV has little impact."
Shuster acknowledges that the sun is responsible for some skin cancers, like basal and squamous cell, but, says he, "these are virtually benign and mostly trivial." (4)
The latest paper to address these questions and to raise even larger discrepancies came out of Sweden this month and was published in the Journal of Internal Medicine. In it, the authors concluded that the risk of avoiding the sun was at least equal to and maybe greater than the risk of all-cause mortality associated with smoking. (2)
Whether it is the benefit of the more heath-protective, sulfated form of vitamin D (that we just can not get from supplements or food) or it is some other age-old mechanism that has been with us throughout human evolution and we just have not been able to isolate or identify it, being outdoors in the sun is starting to look more and more like part of the solution and less and less like the problem. Obviously we should still try and avoid serious burning and over-exposure, but at the same time we should stop running from the sun as though we were made of snow.
Get at least an hour of direct sunlight per day whenever possible and use a large hat or other form of shade when seeking protection as opposed to relying on sunscreen and sunblock which stop the vitamin D generating UVB but do nothing to reduce the equally damaging UVA light. Also, if you are interested in learning more about this turn of events in the area of skin cancer and sunlight, be sure to read the research papers provided here.
(1) Levell NJ et al. Melanoma epidemic: a midsummer night's dream? Br J Dermatol. 2009 Sep;161(3):630-4.
(2) Lindqvist PG et al. Avoidance of sun exposure as a risk factor for major causes of death: a competing risk analysis of the Melanoma in Southern Sweden cohort. J Intern Med. 2016 Mar 16.
(3) Merrill SJ et al. Exponentially increasing incidences of cutaneous malignant melanoma in Europe correlate with low personal annual UV doses and suggests 2 major risk factors Dermato-Endocrinology, 2015; 7(1), e1004018. http://doi.org/10.1080/19381980.2014.1004018.
(4) Horowitz, Janice. Dueling Docs - Does the Sun Really Cause Melanoma? Huffpost Healthy Living. 2011 Nov 17. http://www.huffingtonpost.com/janice-horowitz/dueling-docs---does-the-s_b_203801.html
Merrill SJ et al. (2015). Exponentially increasing incidences of cutaneous malignant melanoma in Europe correlate with low personal annual UV doses and suggests 2 major risk factors. Dermato-Endocrinology, 7(1), e1004018. http://doi.org/10.1080/19381980.2014.1004018
- "We also discovered the incidence of CMM significantly increased with decreasing personal annual UV dose from 1960, when it was almost insignificant, to 2000. UV and other DNA-damaging agents can activate viruses, and UV-induced cytokines can hide HPV from immune surveillance, which may explain why CMM also occurs in anatomical locations where the sun does not shine. Thus, we propose the 2 major risk factors for getting CMM are intermittent UV exposures that result in low cutaneous levels of vitamin D3 and possibly viral infection."
Wright F and Weller RB. Risks and benefits of UV radiation in older people: More of a friend than a foe? Maturitas. 2015 Aug;81(4):425-31. doi: 10.1016/j.maturitas.2015.05.003. Epub 2015 May 19.
- "Advice on healthy sun exposure needs to be reconsidered, with reduction in all-cause mortality and morbidity as the primary end point."
Levell NJ et al. Melanoma epidemic: a midsummer night's dream? Br J Dermatol. 2009 Sep;161(3):630-4. doi: 10.1111/j.1365-2133.2009.09299.x. Epub 2009 Jun 9.
- "We therefore conclude that the large increase in reported incidence is likely to be due to diagnostic drift which classifies benign lesions as stage 1 melanoma. This conclusion could be confirmed by direct histological comparison of contemporary and past histological samples. The distribution of the lesions reported did not correspond to the sites of lesions caused by solar exposure."
Dr. John Bagnulo is the Director of Nutrition at Functional Formularies and leads nutrition research and development initiatives. Learn more about Dr. Bagnulo here.