Benefits of sun exposure by Marc Sorenson, EdD…
A new study on nutrition and skin aging corroborates what I have said previously in this blog: Sunlight is not the guilty party when skin problems occur; it is only one of many factors that influence the skin, and in some cases the influence is protective. And of course, sun exposure influence on the other organs of the body is overwhelmingly healthful.
To the extent that sun causes skin damage, it does so due to lack of proper nutrients in the diet, and there is little doubt that there will be some damage caused by sun exposure without proper nutrition. We eat too many toxic fats, too much meat and cheese, too much sugar and too many refined carbohydrates. At the same time we eat far too few vegetables and fruits, which can protect all the tissues in the body, including skin. Much of that protection is due to the high antioxidant levels of fruits and veggies. It is normal for humans to be exposed to sunlight, and it is equally normal for humans to take in the nutrients necessary to prevent skin damage, so that the sun may heal the body without harming our largest organ.
One of those antioxidants is astaxanthin, a new “superstar” in the antioxidant field. A new study shows that a group of mice that were exposed to Ultraviolet A Light (UVA,) lost water in the skin and developed wrinkles (both signs of skin aging).[1] But in a group of mice that were also exposed to UVA and were supplemented with astaxanthin, no such skin aging occurred. This information demonstrates that poor nutritional habits may make sun exposure dangerous to the skin, because it is working without God’s natural balancing through nutrition. Our atrocious eating (and drinking) habits lead to skin damage, and sun exposure gets the blame.
Fruits and vegetable consumption help protect the skin, but other nutritional factors damage the skin. Alcohol consumption is one such factor; in one investigation, those persons who were in the highest quintile (fifth) of alcohol consumption were shown to have a 65% increased risk of melanoma. [2] Another indicated a 250% increased melanoma risk among those who consumed two or more alcoholic drinks per day,[3] and a third demonstrated that those persons who consumed seven or more drinks per week had 64% greater risk of melanoma and a 23% greater risk of non-melanoma skin cancer when compared to non-drinkers.[4] There are at least two other negative dietary habits that correlate to increased skin-cancer risk: first, the highest dairy-product consumption has also been shown to correlate to a 2½ times increased in risk of developing a non-melanoma carcinoma (common skin cancer).[5] Secondly, the types of fats we consume are exceptionally important. Fats we consume in junk foods are deadly, both for overall health and for skin cancer. They are filled with free-radical molecules that wreak havoc on the skin; if we eat such fats without massive quantities of colorful fruits and veggies, we will be much more susceptible to skin damage and potential cancers of all kinds.
Sun exposure is absolutely essential for human health; but to protect yourself against any damage to the skin, eat the foods that were made for humans!
[1] Komatsu T, Sasaki S, Manabe Y, Hirata T, Sugawara T. Preventive effect of dietary astaxanthin on UVA-induced skin photoaging in hairless mice. PLoS One. 2017 Feb 7;12(2):e0171178.
[2] Millen AE, Tucker MA, Hartge P, Halpern A, Elder DE, Guerry D 4th, Holly EA, Sagebiel RW, Potischman N. Diet and melanoma in a case-control study. Cancer Epidemiol Biomarkers Prev. 2004 Jun;13(6):1042-51.
[3]Bain C, Green A, Siskind V, Alexander J, Harvey P. Diet and melanoma. An exploratory case-control study. Ann Epidemiol 1993;3:235-38.
[4]Jessica T. Kubo, Michael T. Henderson, Manisha Desai, Jean Wactawski-Wende, Marcia L. Stefanick, Jean Y. Tang. Alcohol consumption and risk of melanoma and non-melanoma skin cancer in the Women’s Health Initiative. Cancer Causes Control. 2014 Jan;25(1):1-10.
[5]Hughes MC, van der Pols JC, Marks GC, Green AC. Food intake and risk of squamous cell carcinoma of the skin in a community: The Nambour skin cancer cohort study. Int J Cancer 2006; online publication ahead of print.
Benegits of sun exposure by Marc Sorenson, EdD…
For those who follow my writings, it should now be obvious that the risk of melanoma is decreased by regular sun exposure, and that the evidence for the health benefits of safe sun becomes clearer by the day. I opine that millions of lives could be saved yearly by regular, non-burning sun exposure for the entire population.
Another benefit of moderate sun exposure, or other ultraviolet radiation (UVR), is that it does not cause sufficient DNA damage to prevent efficient repair. A study published in the British Journal of Dermatology reviewed the impact of repeated low level sunlight exposures on vitamin D status and DNA damage/repair in light and brown skinned individuals.[1] The UVR doses were equivalent to 13-17 minutes of midday exposure in the UK. The study reported that no evidence existed for these low-level exposures leading to accumulated DNA-damage, indicating that any damage was quickly repaired. The research also showed that the exposures led to sufficient vitamin D levels in the participants. In addition, it has been shown that “Regular exposure to UV leads to an almost complete disappearance of DNA damage in the basal and suprabasal layers of the epidermis, where the initiating of skin cancer occurs.[2] It is no wonder that regular sun exposure is associated with less melanoma! Soak up some moderate, non-burning sun!
[1] Felton SJ, Cooke MS, Kift R, Berry JL, Webb AR, Lam PMW, de Gruijl FR, Vail A, and Rhodes LE. Concurrent beneficial (vitamin D production) and hazardous (cutaneous DNA damage) impact of repeated low-level summer sunlight exposures. Br J Dermatol. 2016 Jul 14. doi: 10.1111/bjd.14863. [Epub ahead of print]
[2] van der Rhee H, de Vries E, Coomans C, van de Velde P, Jan Willem Coebergh JW. Sunlight: For Better or For Worse? A Review of Positive and Negative Effects of Sun Exposure. Cancer Research Frontiers. 2016 May; 2(2): 156-183.
The necessity of sun exposure for heart health, by Marc Sorenson, EdD…
Despite the fact that higher vitamin D levels are nearly always found to be related to reduced risk of cardiovascular disease[1] and associated diseases such as diabetes mellitus,[2] randomized controlled trials have not found that vitamin D supplementation reduces risk of cardiovascular disease.[3]
Therefore, vitamin D levels are likely a surrogate measurement for sun exposure, meaning that some other photoproduct such as nitric oxide (NO) may be responsible for the lowered risk of CVD. A pair of recent papers reported that leisure-time or recreational outdoor physical activity was significantly associated with reduced risk of cardiovascular disease. In a study in the U.S., both frequency and intensity of outdoor activities were associated with reduced risk, as was higher vitamin D level.[4] When vitamin D levels were removed from the equation, an inverse association was still found between outdoor recreational activity and mortality. The authors stated the following: “The underlying mechanism for this association may not involve 25(OH)D hence, further studies are warranted to confirm and investigate the underlying mechanism.” I would suggest that nitric oxide was the protective photoproduct, produced by sun exposure, which lessened the risk of CVD with outdoor activity.
Similar findings have been found for hypertension, diabetes mellitus, heart failure, stroke, and myocardial infarction (heart attack). In a study in Finland, older adults who had moderate leisure-time activity had 30-40% reduced mortality and cardiovascular disease rates than those with low activity levels, while those with high activity levels had 50% lower rates.[5]
Two messages from this research: (1) Start living more of your life outdoors. (2) Be sure to obtain plenty of non-burning sun exposure during you outdoor activity. Your life may depend on it.
[1] Wang L, Song Y, Manson JE, Pilz S, März W, Michaëlsson K, Lundqvist A, Jassal SK, Barrett-Connor E, Zhang C, Eaton CB, May HT, Anderson JL, Sesso HD. Circulating 25-hydroxy-vitamin D and risk of cardiovascular disease: A meta-analysis of prospective studies. Circ Cardiovasc Qual Outcomes. 2012 Nov 1;5(6):819-29.
[2] Song Y, Wang L, Pittas AG, Del Gobbo LC, Zhang C, Manson JE, Hu FB. Blood 25-hydroxy vitamin D levels and incident type 2 diabetes: a meta-analysis of prospective studies. Diabetes Care. 2013 May;36(5):1422-8.
[3] Veloudi P, Jones G, Sharman JE. Effectiveness of vitamin D supplementation for cardiovascular health outcomes. Pulse 2016;4:193-207 https://www.karger.com/Article/FullText/452742
[4] Donneyong MM, Taylor KC, Kerber RA, Hornung CA, Scragg R. Is outdoor recreational activity an independent predictor of cardiovascular disease mortality – NHANES III? Nutr Metab Cardiovasc Dis. 2016 Aug;26(8):735-42.
[5] Barengo NC, Antikainen R, Borodulin K, Harald K, Jousilahti P. Leisure-Time Physical Activity Reduces Total and Cardiovascular Mortality and Cardiovascular Disease Incidence in Older Adults. J Am Geriatr Soc. 2016 Dec 26. doi: 10.1111/jgs.14694. [Epub ahead of print]
By Marc Sorenson, EdD, for sun exposure…
A new research paper on sun exposure and cancer has some interesting observations and some errors.[1] It is entitled, Does Sunlight protect us from cancer? Here is the abstract of the article, verbatim.
“The Ultraviolet (UV) radiation contained in sunlight is a powerful mutagen and immune suppressant which partly explains why exposure to solar UV is the biggest risk factor for the development of cutaneous tumors. Evidence is building that sunlight may be protective against some internal malignancies. Because patients with these tumors are often vitamin D deficient, this has led some to propose that vitamin D supplementation will be beneficial in the treatment of these cancers. However, the results from already completed trials have been disappointing which has given weight to the argument that there must be something else about sunlight that explains its cancer-protecting properties.”
The first sentence, of course, is false. The idea, that sun exposure is the biggest risk factor for skin cancer, is erroneous. We have presented materials many times, proving that melanoma is not caused by sun exposure, and that sun exposure is protective against that disease. And as regards common skin cancers, we have shown that high-fat nutrition, lack of antioxidants, meat consumption and alcohol intake are all risk factors. Search the blogs on this site to read the different articles.
The statement is correct, of course, that sunlight is protective against many internal cancers. Dr. Bill Grant and I are finishing our book, Embrace the Sun, where we present nearly all of the research on the protective influence of sun exposure against cancer.
The statement that vitamin D research has been disappointing is both true and false. Randomized controlled studies (RCTs) have shown the vitamin D supplements do have a protective effect against internal cancers, contrary to the statement by the researchers.
Finally, let’s look at the statement that there is something beyond vitamin D that explains the cancer-protecting properties of sun exposure. That is partially true. Beyond vitamin D, the sun causes the production of nitric oxide, serotonin, endorphin and BDNF, all of which are vital to human health, and may have their own cancer-protective properties.
The bottom line? Eat correctly (avoid junk), REGULARLY soak up some sun around midday and get plenty of exercise. That advice will be a boon to your health in myriad ways.
By Marc Sorenson, EdD. For sun exposure…
Can sun exposure reduce rheumatoid arthritis (RA)?
RA is a terrible, crippling disease, which causes chronic inflammation of the joints, the tissue around the joints, and certain organs in the body.[1] Like most diseases, it is one to be avoided and prevented when possible, and sun exposure may indeed help. At our former health resort in Southern Utah, we observed that many people were able to reduce the swelling and inflammation of this disease through adherence to a mostly plant-based nutrition program, or so we thought. Sun exposure in our very sunlit climate may have also played a critically-important part. One of our attendees was a former writer and piano player whose fingers had lost their ability to use the keyboards on either the computer or the piano. In less than two weeks she had gained sufficient range of motion in her hands to resume her two important activities. In addition, the swelling of her knuckles was profoundly reduced. And whereas the nutrition we used was doubtlessly responsible for much of her success, sun exposure was likely responsible for the remainder.
One paper demonstrated that at high latitudes, where sun exposure is considerably less available, the rate of RA is much higher than at lower latitudes.[2] RA is also more severe in winter,[3] a time of less sun exposure. In another report from researchers in Ireland (a northern country with little sun exposure due to overcast conditions), it was shown that 70% of patients had low vitamin D levels and that 26% were severely deficient.[4] And in an investigation using data from the nurses health study, those women who were in the highest versus the lowest category of UVB (ultraviolet light exposure from sun or other sources), had a 21% decreased RA risk.[5]
RA is an autoimmune rheumatic disease (ARD), and seasonal vitamin D declines may trigger flares in (ARD).[6] Such declines, of course, are a result of decreasing sun exposure in the colder seasons.
Arthritic joints carry another devastating side effect. Hip replacement surgery is often prescribed for arthritic conditions, and those people who go through total-hip-replacement procedures are 4.7 times as likely to have an ischemic stroke, and 4.4 times as likely to have a hemorrhagic stroke in the first two weeks post surgery.[7] Those stroke risks remain elevated for 6-12 weeks.
Eat correctly and safely soak up the sun. It’s a better option than hip replacement and potential stroke!
[1] Medicinenet.com. Definition of rheumatoid arthritis. http://www.medterms.com/script/main/art.asp?articlekey=5354.
[2]Vieira VM, Hart JE, Webster TF, Weinberg J, Puett R, Laden F, CostenbaderKH, Karlson EW. Association between Residences in U.S. Northern Latitudes and Rheumatoid Arthritis: A Spatial Analysis of the Nurses’ Health Study. Environ Health Perspect. 2010 Mar 25. [Epub ahead of print]
[3]Cutolo M, Otsa K, Uprus M, Paolino S, Seriolo B. Vitamin D in rheumatoid arthritis. Autoimmun Rev 2007;7:59-64
[4]Haroon, M. Report to European Union League Against Rheumatism, June 13, 2008.
[5]Arkema EV, Hart JE, Bertrand KA, Laden F, Grodstein F, Rosner BA, Karlson EW, CostenbaderKH. Exposure to ultraviolet-B and risk of developing rheumatoid arthritis among women in the Nurses’ Health Study. Ann Rheum Dis. 2013 Apr;72(4):506-11
[6]CutoloM1, Paolino S, Sulli A, Smith V, Pizzorni C, Seriolo B. Vitamin D, steroid hormones, and autoimmunity. Ann N Y Acad Sci. 2014 May;1317:39-46.
[7]Lalmohamed A, Vestergaard P, Cooper C, de Boer A, Leufkens HG, van StaaTP, de Vries F. Hip replacement surgery and stroke. Stroke 2012;43(12):3225-9.
Sun and cognitive ability by Marc Sorenson, EdD, Sunlight Institute…
If you have depression, you may also have cognitive impairment, according to older research that I just became aware of. The researchers measured cognitive abilities among approximately 14,000 depressed subjects and then exposed them to either one day of sunlight or two weeks of sunlight. They then determined if cognitive disabilities were associated with the sun they obtained.[1]
The results were impressive: Those who were sun-deprived for two weeks had 2.5 times the risk of being cognitively impaired, compared to those who had sufficient sunlight. A one-day exposure made no significant difference in cognition.
Results of other research, based on a 15-year residential history of varying degrees of sun exposure, has also shown that cognitive impairment in persons who were below the median exposure to sun, was 88% greater than those who were above the median.[2] The researchers mentioned vitamin D as a possible mechanism by which sun positively influenced cognition, but they also remarked that regulation of the circadian rhythm by sunlight could be a factor.
Several other studies showed a close, positive association between vitamin D levels and cognition, and as we know, vitamin D levels in most cases are a surrogate measurement for sun exposure.
The message is to get plenty of sunlight to improve mental clarity. Happy thinking!
[1] Shia T Kent, Leslie A McClure, William L Crosson, Donna K Arnett, Virginia G Wadley and Nalini Sathiakumar. Effect of sunlight exposure on cognitive function among depressed and non-depressed participants: a REGARDS cross-sectional study. Environmental Health 2009, 8:34
[2] Kent ST, Kabagambe EK, Wadley VG, Howard VJ, Crosson WL, Al-Hamdan MZ, Judd SE, Peace F, McClure LA. The relationship between long-term sun radiation and cognitive decline in the REGARDS cohort study. Int J Biometeorol. 2014 Apr;58(3):361-70.
Sun exposure and health By Marc Sorenson, EdD, Sunlight Institute…
New research shows that sunlight boosts the effectiveness of T-cells, an integral part of the immune system.[1] T-cells are a type of lymphocyte that recognizes and binds to foreign invaders, thereby rendering them harmless. This is an important new finding, which demonstrates another beneficial effect of sun—one that has no relationship to vitamin D.
The key player in this action is the blue-light spectrum of sunlight that stimulates hydrogen peroxide production. The hydrogen peroxide (HP) causes T-cells to move to the site of infection, and it (HP) is also involved in the killing of noxious bacteria. Dr. Gerard Ahern, one of the primary investigators, stated it in this way: “T cells, whether they are helper or killer, need to move to do their work, which is to get to the site of an infection and orchestrate a response. This study shows that sunlight directly activates key immune cells by increasing their movement.”
Also interesting is the fact that the skin has a large share of the total T-cells in humans, about twice the number circulating in the blood. Think about this magnificent body of ours! It is programmed to immediately respond to any invasions that may occur in the skin, and sun exposure, if we take full advantage of it, immediately accelerates the process. Then, when the t-cells are activated by the blue light, they can move rapidly to other body areas where they can be utilized.
Sun exposure has also been found to have an exceptionally important and positive effect on autoimmune diseases such as lupus, MS, rheumatoid arthritis and others, many of which have been found to associate with low solar radiation and vitamin D.[2] In this case, a different type of T-cell, called a regulatory T-cell, attacks the body’s own tissue, mistaking it for a foreign invader, and causes severe damage. The mechanism of autoimmune disease prevention by sunlight may be the suppression of regulatory T cells, in a manner that impedes the immune system’s attacks on its own tissues.[3] [4]
Sunlight is one of God’s (or Nature’s) greatest miracles. Be sure to receive your full contingent of wonderful, non-burning sun.
[1] Thieu X. Phan, Barbara Jaruga, Sandeep C. Pingle, Bidhan C. Bandyopadhyay, Gerard P. Ahern. Intrinsic Photosensitivity Enhances Motility of T Lymphocytes. Scientific Reports, 2016;6:39479
[2] Schwalfenberg GK. Solar radiation and vitamin D: mitigating environmental factors in autoimmune disease. J Environ Public Health. 2012;2012:619381.
[3]ArtukovićM1, Ikić M, Kustelega J, Artuković IN, Kaliterna DM. Influence of UV radiation on immunological system and occurrence of autoimmune diseases. Coll Antropol. 2010 Apr;34 Suppl 2:175-8.
[4]Marsh-Wakefield F, Byrne SN. Photoimmunology and Multiple Sclerosis. Curr Top Behav Neurosci. 2015;26:117-41.
Tanning bed use, By Marc Sorenson, EdD. Sunlight Institute.
Sun exposure and tanning-bed exposure have been much maligned by those who would increase sunscreen sales and other “protection” against melanoma. So a new paper has been written regarding the truth about tanning beds. According to this paper, Risk of melanoma with tanning beds is slightly associated with home use, but there is no significant increase in risk with beds used in tanning salons. This is according to a soon-to-be-published analysis of studies that differentiated between home-use tanning beds and salon use of tanning beds.[1]
The analysis showed that when all tanning devices were considered together, tanning bed use was associated with a 15%-20% increased risk of melanoma. However, when home-use tanning was separated from salon use, salon use showed only a 5% increased risk, which was not significant. In other words, there may have been no risk whatever. In fact, in three of the studies that were part of the analysis, overall use of tanning beds associated to a lessened risk of melanoma.
Therefore, if there is any increased risk of melanoma with tanning-bed use, it is all due to the use of home units. This is what we might expect, since salons take care to assess skin type and monitor the time spent in the unit.
Before we decide to eschew the use of home units, however, we should also take into consideration the very healthful benefits of tanning-bed use in general. Here are a few well-documented facts about the benefits:
- Tanning bed use is associated with a reduced risk of clots.[2]
- Tanning-bed use is associated with increased vitamin D levels.[3]
- Tanning-bed use is associated with stronger bones.[4]
- Tanning-bed use can cure psoriasis and eczema and tanning beds are often recommended by dermatologists.[5]
- Tanning-bed use more than three times yearly is associated with a 40-50% reduced risk of endometrial cancer.[6]
- Tanning-bed use is associated to lower breast-cancer risk.[7]
- A 20- year study demonstrated that both sun exposure and tanning-bed exposure reduced the risk of death; women who used tanning beds were 23% less likely to die of any cause than women who did not use them.[8]
The key to safe tanning-bed use is the same key as for safe sun exposure: Don’t be taken in by the anti-sun, anti-tanning movement.
[1] Hoel, D. Commercial Tanning Salons and Melanoma Risk. Letter to the editor, Dermato-endocrinology. Not yet published.
[2] Lindqvist PG, Epstein E, Olsson H. Does an active sun exposure habit lower the risk of venous thrombotic events? A D-lightful hypothesis. J Thromb Haemost. 2009 Apr; 7(4):605-10.
[3] Holick, M. Boston University. “Effects Of Vitamin D And Skin’s Physiology Examined.” Science Daily 21 February 2008 <http://www.sciencedaily.com¬ /releases/2008/02/080220161707.htm>.
[4] Tangpricha V, Turner A, Spina C, Decastro S, Chen TC, Holick MF. Tanning is associated with optimal vitamin D status (serum 25-hydroxyvitamin D concentration) and higher bone mineral density. Am J Clin Nutr 2004;80:1645-49.
[5] Radack KP, Farhangian ME, Anderson KL, Feldman SR. A review of the use of tanning beds as a dermatological treatment. Dermatol Ther (Heidelb). 2015 Mar;5(1):37-51.
[6] Epstein E, Lindqvist PG, Geppert B, Olsson H. A population-based cohort study on sun habits and endometrial cancer. Br J Cancer. 2009 Aug 4;101(3):537-40.
[7] Yang L, Veierød MB, Löf M, Sandin S, Adami HO, Weiderpass E. Prospective study of UV exposure and cancer incidence among Swedish women. J Intern Med. 2014 Jul;276(1):77-86
[8] Lindqvist PG, Epstein E, Landin-Olsson M, Ingvar C, Nielsen K, Stenbeck M, Olsson H. Avoidance of sun exposure is a risk factor for all-cause mortality: results from the Melanoma in Southern Sweden cohort. J Intern Med. 2014 Jul;276(1):77-86.
Sun exposure Information by Marc Sorenson, EdD. Sunlight Institute.
There are 62,700 cases of kidney cancer and 14,240 deaths annually. Kidney cancer incidence has tripled since the early 1980s, and some researchers have felt that environmental factors may have played a part in that worrisome increase. One of those factors may be sun exposure, which may be vital to the prevention of the disease. The newest research measured sun exposure, which was based on the average number of hours per day outdoors in the summer, during different periods of life.[1] The researchers also took into consideration the age of the subjects and adjusted the data for other factors that may associate to kidney cancer.
These were some of the research results:
- Higher summer sun exposure at age 40+ years, but not at younger ages, was associated with a significantly lower risk of thyroid cancer. When comparing the highest quartile (fourth) of sun exposure to the lowest quartile, there was a 44% reduction in risk.
- Average lifetime sun exposure was not associated with thyroid-cancer risk.
- Recent summer sun exposure was closely associated with a decreased risk of thyroid cancer.
One of the salient points, in my mind, is that the best sun exposure is that which is habitual or consistent. In the case of kidney cancer, sun exposure in the past does not indicate that the disease will be avoided in the future. Only recent sun exposure provides protection. However, this is not necessarily true of other diseases; in the case of breast and prostate cancers, childhood sun exposure is associated with a lesser risk of the diseases in adulthood.
Previous research has also confirmed the importance of sun exposure on kidney-cancer prevention. There is a strong inverse correlation between sun exposure and kidney cancer. For example, one study that used NMSC as a measure of sun exposure, determined that sun exposure reduced the risk of several cancers, including kidney cancer, from 35% to 42%.[2] Kidney cancer mortality rates were found to be strongly inversely correlated with solar UVB doses in Dr. William Grant’s 2002 and 2006 ecological studies.[3] [4]
Recent research by Dr. Sara Karami and colleagues, demonstrates that in women, there is a significant reduction in kidney cancer with high levels of sun exposure.[5] Those women with the highest fourth of sun exposure showed a 33% reduction in risk. Interestingly, the data was adjusted for vitamin D intake, and the results still showed sun exposure to have a stand-alone protective influence on kidney cancer—another indication that sun exposure has protective effects beyond vitamin D production.
Remember that a lifetime habit of non-burning sun exposure will always provide the best health outcomes.
[1] Rachel D Zamoiski, Elizabeth K. Cahoon, D. Michal Freedman, et al. Prospective study of ultraviolet radiation exposure and thyroid cancer risk in the United States. Cancer Epidemiol Biomarkers Prev Published Online First December 2, 2016.
[2] Tuohimaa P, Pukkala E, Scélo G, Olsen JH, Brewster DH, Hemminki K, Tracey E, Weiderpass E, Kliewer EV, Pompe-Kirn V, McBride ML, Martos C, Chia KS, Tonita JM, Jonasson JG, Boffetta P, Brennan P. Does solar exposure, as indicated by the non-melanoma skin cancers, protect from solid cancers: vitamin D as a possible explanation. Eur J Cancer 2007;43(11):1701-12
[3] Grant WB. An estimate of premature cancer mortality in the U.S. due to inadequate doses of solar ultraviolet-B radiation. Cancer. 2002 Mar 15;94(6):1867-75.
[4] Grant WB, Garland CF. The association of solar ultraviolet B (UVB) with reducing risk of cancer: multifactorial ecologic analysis of geographic variation in age-adjusted cancer mortality rates. Anticancer Res. 2006 Jul-Aug;26(4A):2687-99.
[5] Karami S, Colt JS, Stewart PA, Schwartz K, Davis FG, Ruterbusch JJ, Chow WH, Wacholder S, Graubard BI, Purdue MP, MooreLE. Short Report: A case-control study of occupational sun exposure and renal cancer risk. Int J Cancer. 2015 Oct 27.