The slimming, healing Sun.

By Marc Sorenson, EdD, for safe sun exposure…

There is an alarming increase in obesity In the United States. Obesity is determined by a measurement called Body-mass index (BMI) which compares a person’s height with his weight and uses a mathematical formula for its calculation. To quickly calculate your BMI, go to this website: A BMI less than 24.9 is considered normal; 25-29.9 overweight; 30 and over obese, and 40+ extremely (or morbidly) obese. Since the early 1960s the prevalence of obesity among adults more than doubled, increasing from 13.4% of adults in 1960 to 37.5% in 2010. We obviously have a severe problem, with two in three adults now either overweight or obese.[1]

There is little doubt as to the cause of obesity. We lack exercise, eat high-calorie junk foods and have moved away from sun exposure, this due to indoor living and a misguided fear of skin cancer. Most people would not put sun exposure in the list of causes, but research shows that it may play an important part in this increasing plague.

Marching in lockstep with the increase in obesity is an increase in type-2 diabetes and metabolic syndrome, which is defined as group of disorders (high blood pressure, abdominal obesity, high cholesterol, high triglyceride levels, low HDL levels and insulin resistance) that are linked to increased risk of cardiovascular disease and type 2 diabetes. This was the conclusion of a recent review on the influence of sun exposure on these conditions: “Overall, emerging findings suggest a protective role for UVR and sun exposure in reducing the development of obesity and cardiometabolic dysfunction.”[2]

Other research has led to similar conclusions. A recent study from Northwestern Medicine demonstrates that timing and intensity of light correlate with body mass index (BMI).[3] This research showed that exposure to bright morning light was directly related to BMI. After adjusting for confounders such as diet, exercise and sleep timing, it was determined that very early sun exposure correlated remarkably to lower BMI; even when light intensity was equal at different times of the day, those who received the earliest bright light had lower BMI. In fact, for each hour later in the day that the light exposure occurred, BMI increased by 1.28 units. This fact is exceptionally important, since a person who has a BMI of 25 (upper ideal range) could approach 30, or obesity, simply by the habit of sun exposure later in the day, i.e. 10:00 AM rather than 6:00 AM. The authors of this research suggested that the mechanisms involved in weight control by early light exposure could be the following: (1) resetting the circadian rhythm (internal clock), (2) the greater quantity of blue light in morning sun and (3) effects on melatonin production. Whatever the mechanisms, we now know that early-morning sun is important to weight control. It may also be important to other health issues.

Another scientific paper was recently published that “sheds more light” on the subject of obesity.[4] This research was conducted on mice that were placed on a high-fat diet and then exposed to non-burning ultraviolet radiation (UVR) during a three-month experiment. The mice, without the benefit of UVR, would have been expected to gain weight rapidly, but when they were exposed to UVR, the weight gain was impressively reduced; the UVR treatment achieved 30-40% less weight gain, compared to the expected weight gain with the high-fat diet. The quantity of UVR exposure to the mice was proportionally equal to the quantity of sun exposure that a human would be exposed to by standing in the sun for ten minutes at noon.

So add sun exposure to the list of aids for obesity. Just be safe and do not burn. Let’s learn to live off the fat of the land but not be part of it!


[2] Gorman S, Lucas RM, Allen-Hall A1, Fleury N, Feelisch M. Ultraviolet radiation, vitamin D and the development of obesity, metabolic syndrome and type-2 diabetes. Photochem Photobiol Sci. 2016 Dec 23. doi: 10.1039/c6pp00274a. [Epub ahead of print]

[3] Reid KJ, Santostasi G, Baron KG, Wilson J, Kang J, Zee PC. Timing and intensity of light correlate with body weight in adults. PLoS One 2014;2;9(4)

[4] Geldenhuys S, Hart PH, Endersby R, Jacoby P, Feelisch M, Weller RB, Matthews V, Gorman S. Ultraviolet radiation suppresses obesity and symptoms of metabolic syndrome independently of vitamin D in mice fed a high-fat diet. Diabetes. 2014 Nov;63(11):3759-69

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New and interesting research on cancer and sun exposure.

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.

[1]Marshall JE, Byrne SN. Does sunlight protect us from cancer? Photochem Photobiol Sci. 2017 Jan 19. doi: 10.1039/c6pp00332j. [Epub ahead of print] 

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Embrace Sun exposure and prevent Rheumatoid Arthritis.

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] Definition of rheumatoid arthritis.

[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.


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Health Benefits of Tanning Beds shown in new Study.

By Marc Sorenson, EdD, Sunlight Institute, for sensible tanning bed use

The online magazine, Life Science Daily, just posted an article regarding the health benefits of UV light from tanning beds. Surprisingly, they were quoting from research published in the British Journal of Dermatology. I say “surprising,” because so many dermatologists and dermatological organizations are vehemently opposed to a single ray of sunlight touching the skin. And heaven forbid someone should use a tanning bed.

Three times weekly, adult subjects were exposed to a tanning bed that emitted 95% UVA rays and 5% UVB rays, which is approximately the amount of UVA and UVB that midday summer sunlight emits. Each exposure lasted six minutes. Here are some of the salient points reported in the article:

  • Any damage caused by the light exposure was repaired by the by the skin.
  • One of the positive benefits of the light was the production of nitric oxide, which improves blood flow and reduces blood pressure.
  • Another positive benefit was the productions of beta-endorphins, which reduce depression.
  • A third benefit, of course, is the production of vitamin D, necessary for growth and bone strength, as well as asthma prevention.

Here is one of the important quotes from the article, from Dr. Michael Holick:  “What this study shows is that you can get a reasonable amount of sunlight that would make enough vitamin D in your skin living in the U.K. Yes, the DNA is somewhat damaged, but because the body has adapted to its environment, it has the ability to repair it.”  Dr. Holick also suggested that people become educated about the wide range of health benefits from modest sun exposure, which is superior to taking vitamin D supplements.

Step by step, the truth is overcoming the powers of darkness! Seek the sun, and let a tanning bed enhance your health in the winter.

Click here to read the article.

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Sun Exposure is directly associated with Cognitive (mental) Ability.

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.

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UVB light prevents atherosclerosis by reducing inflammation.

UVB exposure benefits by Marc Sorenson, EdD. Sunlight Institute…

UVB is a spectrum of sunlight that is responsible for stimulation of vitamin D production in the skin. It also has many other effects, including the suppression of inflammation in the skin, and thus has been used to very successfully treat skin diseases such as psoriasis and eczema.[1] [2] [3] [4]

Since inflammation is also necessary to produce the condition of atherosclerosis (arterial plugging or occlusion) in arteries, it would be interesting to know whether UVB light might also have the same anti-inflammatory effects in those arteries. If so, the UVB effect could inhibit or eliminate atherosclerosis, and by so doing provide an entirely new treatment for heart disease and other vascular events such as stroke and intermittent claudication.

The idea that UVB could prevent atherosclerosis by reducing inflammation in arteries was recently studied by Japanese researchers.[5] [6] Using a mouse model, they demonstrated that UVB light irradiation, once weekly for 14 weeks, leads to an increase in the action of T-regulatory cells that inhibit inflammation. In addition, UVB exposure also reduced the production of another type of T-cell that is pro-inflammatory, and thereby proatherogenic (leading to the production of atherosclerosis). These two effects of UVB light reduce the development and progression of atherosclerosis. Or stated differently, the research shows that sun exposure is critically-important therapy to reduce and prevent heart and other vascular diseases.

Protect your heart by being sure to obtain sufficient non-burning UVB light from sun exposure or other sources such as the UVB lamps used by the researchers. It is important to note that neither skin cancer nor skin inflammation were observed following UVB exposure.

This is another breakthrough study that emphasizes the necessity of sun exposure for human health.

[1] National Psoriasis Foundation web site Oct. 2005.

[2] Yelverton CB, Kulkarni AS, Balkrishnan R, Feldman SR. Home ultraviolet B phototherapy: a cost-effective option for severe psoriasis. Manag Care Interface 2006;19:33-36, 39.

[3] Situm M, Bulat V, Majcen K, Dzapo A, Jezovita J. Benefits of controlled ultraviolet radiation in the treatment of dermatological diseases. Coll Antropol. 2014 Dec;38(4):1249-53.

[4] Gupta A, Arora TC, Jindal A, Bhadoria AS. Efficacy of narrowband ultraviolet B phototherapy and levels of serum vitamin D3 in psoriasis: A prospective study. Indian Dermatol Online J. 2016 Mar-Apr;7(2):87-92.

[5] Naoto Sasaki, Tomoya Yamashita, Kazuyuki Kasahara, Atsushi Fukunaga, Tomoyuki Yamaguchi, et al. UVB Exposure Prevents Atherosclerosis by Regulating Immunoinflammatory Responses. Arterioscler Thromb Vasc Biol. 2016;36:00-00.

DOI: 10.1161/ATVBAHA.116.308063.)

[6] Hafid Ait-Oufella, Andrew P. Sage. Editorial. The Sunlight. A New Immunomodulatory Approach of Atherosclerosis. (Arterioscler Thromb Vasc Biol. 2017;37:7-9. DOI: 10.1161/ATVBAHA.116.308637.)


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Stay well! Sun exposure enhances immunity independently of vitamin D.

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.

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Tanning beds in salons do not increase melanoma risk.

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 <¬ /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.

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High Sun Exposure may reduce Kidney Cancer Risk.




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.

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Research again shows sun exposure reduces myopia.

By Marc Sorenson, EdD. For sun exposure…

It should be well-known by now, but the relationship between sun exposure and myopia (nearsightedness) is still being studied. And as before, the answer is the same: sun deprivation is associated to a greater myopia risk. The difference in this research was the study population, which was a random sample of participants 65 years and older from Europe.[1] Among the factors that the researchers considered important, were vitamin D blood levels, vitamin D polymorphisms, ultraviolet B radiation (UVB), and years in education. Of these factors, only ultraviolet B radiation (UVB) was associated with reduced odds for myopia, especially if higher UVB exposure occurred during adolescence and early adulthood. This is another research paper that shows sun exposure to be protective against a disease, independent of vitamin D.

The authors of the study made this conclusion: “This study, while not designed to determine cause and effect relationships, suggests that increased ultraviolet B exposure, a marker of sunlight exposure, is associated with reduced myopia.

This is one in a long line of studies that show the relationship of sun exposure to myopia, and it doesn’t take a rocket scientist to determine that myopia is caused by lack of sun exposure. The evidence has been building for years. For example, one of the studies showed that the lowest risk of myopia among 12-year-old students was found among those who reported the highest levels of outdoor activity.[2] Some might surmise that the key ingredient was exercise, but that idea was refuted by the fact that there was no association between indoor activity and myopia. Something besides exercise had to be leading to the lower risk of myopia among children who were actively outdoors; it had to be sun. The lower risk of myopia persisted after adjusting for genetic factors, ethnicity and the amount of near work. This is important, because for many years there was an assumption that long hours of study indoors, staring closely at books (near work) and never focusing on distant objects, led to myopia. This study belied that error.

This same research showed that the prevalence of myopia among Chinese children living in Singapore was 29.1%, whereas Chinese children living in Sydney, Australia, had a prevalence rate of only 3.3%. The children in Sydney spent about 13.8 hours per week outdoors compared to 3.05 hours in Singapore. In other words, the children who spent most or their lives indoors had 9.5 times the risk of developing myopia!

Depriving either adults or children of their time in the sunlight leads to myriad illnesses, only one of which is myopia. When will we learn?

[1] Katie M. Williams, FRCOphth; Graham C. G. Bentham, MA; Ian S. Young, MD; et al Association Between Myopia, Ultraviolet B Radiation Exposure, Serum Vitamin D Concentrations, and Genetic Polymorphisms in Vitamin D Metabolic Pathways in a Multicountry European Study. Published Online: December 1, 2016. doi:10.1001/jamaophthalmol.2016.4752

[2] Rose KA, Morgan IG, J, Kifley A, Huynh S, Smith W, Mitchell P. Outdoor activity reduces the prevalence of myopia in children. Ophthalmology 2008 Aug;115(8):1279-85.

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