Blood pressure is determined by (1) the amount of blood the heart pumps and the amount of resistance to blood flow in the arteries. Consequently, the more blood the heart pumps, and the tighter the arteries, the higher the blood pressure.[1]
Chronic high blood pressure, or hypertension, can damage arterial walls and can eventually lead to an increased risk from heart disease, heart failure, other arterial diseases, kidney disease, irregular heart rhythms, osteoporosis, cognitive dysfunction, painful intercourse and stroke.[2] High blood pressure, also known as hypertension, is rampant in western societies. Untreated high blood pressure is a major killer. It is especially dangerous because it is primary risk factor for heart disease and stroke.
I have written several blogs on high blood pressure. Nevertheless, the experience of my friend Wayne may provide impetus for hypertension sufferers to try the sunshine solution.
Wayne, a resident of Texas, came to our former health resort seeking help for conditions of high blood pressure, obesity and various other maladies. I recommended, along with our healthful nutrition program, that he should sunbathe daily. Consequently, he “took it to heart” and could be found outside by the pool daily, dutifully soaking up the midday sunlight.
Wayne arrived at our program with a blood pressure of 157 systolic and 97 diastolic (157/97). Most noteworthy, those numbers put him at high risk for a stroke. Normal blood pressures are considered below 120 systolic, and below 80 diastolic. Four weeks later, as a result of his lifestyle changes. His numbers dropped to 125/54, meaning that he progressed from high stroke risk to very low stroke risk. Especially relevant is the fact that these changes were accomplished without medication.
The average drop in blood pressure among all guests at that program was 16 systolic and 12 diastolic. This is remarkable, considering that many of them had normal levels coming in.
Here are just a few of the blood pressure changes accomplished during that time:
- Frieda, from Oregon, lowered her blood pressure 33 points systolic and 30 points diastolic.
- Joyce, from Rhode Island, lowered her blood pressure 31 points systolic and 24 points diastolic.
- Jeff, from Utah, lowered his blood pressure 39 points systolic and 12 points diastolic.
- Susan, from New York, lowered her blood pressure 20 points systolic and 26 points diastolic.
Was all of this success due to sun exposure?
It should not be construed that these results were all a result of sun exposure. Nor should we conclude that hypertension is a result of sun deprivation. Typical American citizens engage daily in “killer” nutrition, subjecting themselves to dietary patterns and chemical additives that never existed in human life until modern times. Therein lie the major causes of hypertension. Hence, part of the improvements in blood pressure were due to the dietary changes we implemented with our guests.
More research regarding sunlight and blood pressure:
Sun exposure can, to an extent, act as an antidote to the poisons we consume. And, it acts much more quickly than dietary changes. Consider this: Dr. Oplander and his colleagues demonstrated that whole-body Ultraviolet A (UVA) irradiation worked what seemed like a miracle.[3] It caused a rapid, significant decrease of 11% in both systolic (upper number) and diastolic (lower number) blood pressure 30 minutes after the exposure. That change lasted up to 60 minutes. The lowered blood pressure lasted up to 60 minutes. Not only did blood pressure decrease, but arterial blood flow increased by 68%.
Nitric oxide, a potent vasodilator (blood-vessel relaxer) that occurs with sun exposure, was the photoproduct that led to these spectacular, important changes. This is important, because UVA is available almost any time the sun shines, winter and summer. Ultraviolet B (UVB) is not available in some areas during winter, due to the sun’s angle. This is especially true in the higher latitudes of the Northern hemisphere, or in the lower latitudes of the Southern hemisphere. UVB stimulates the production of vitamin D. So, it is especially relevant here that vitamin D was not involved in the lowering of blood pressure in Dr. Oplander’s study. Nitric oxide, however, was very involved.
Let’s take a look at one more study of sun exposure and hypertension: research China demonstrates that exposure to sun correlates to a lowered risk:[4] In a randomly selected population of Chinese residents from Macau (where the rate of hypertension is very high), the following risk factors for hypertension were assessed: lack of sun exposure, low intake of fish, smoking, obesity and lack of exercise. An average of more than one-half hour of sun exposure per day, as compared to no sun exposure, predicted a 40% reduced risk for hypertension.
I could go on for another page about the horrors of blood-pressure medication, but what I have said suffices. Non-burning sun exposure is one of the best elixirs for hypertension. In conclusion, one might say that it is no wonder that Wayne overcame his blood pressure problem!
[1] Mayo Clinic Diseases and Conditions: High blood pressure (hypertension). http://www.mayoclinic.org/diseases-conditions/high-blood-pressure/basics/definition/con-20019580 (accessed January 5, 2016).
[2] Ann Pietrangelo. Healthline 2014 http://www.healthline.com/health/high-blood-pressure-hypertension/effect-on-body (accessed January 4, 2016).
[3] Opländer C, Volkmar CM, Paunel-Görgülü A, van Faassen EE, Heiss C, Kelm M, Halmer D, Mürtz M, Pallua N, Suschek CV.. Whole body UVA irradiation lowers systemic blood pressure by release of nitric oxide from intracutaneous photolabile nitric oxide derivates. Circ Res. 2009;105:1031–40.
[4] Ke L, Ho J, Feng J, Mpofu E, Dibley MJ, Feng X, Van F, Leong S, Lau W, Lueng P, Kowk C, Li Y, Mason RS, Brock KE. Modifiable risk factors including sun exposure and fish consumption are associated with risk of hypertension in a large representative population from Macau. J Steroid Biochem Mol Biol 2013 Nov 1 [Epub ahead of print].
Hypertension, or chronic high blood pressure, is determined by the amount of blood the heart pumps and the amount of resistance to blood flow in the arteries. The more blood the heart pumps and the tighter the arteries, the higher the blood pressure.[1] The top number on a blood-pressure measurement, stated in millimeters of mercury (mm/Hg), is called systolic pressure, and the lower number is called diastolic pressure. Hypertension is defined as having a blood pressure > 140/90 mm/Hg. Thirty-one percent of US adults are hypertensive.[2] Hypertension can damage arterial walls and can eventually lead to an increased risk of death from heart disease, heart failure, and other arterial diseases. It is also associated to a higher risk of kidney disease, irregular heart rhythms, osteoporosis, cognitive dysfunction, painful intercourse and stroke.[3] Conventional textbook theory holds that blood pressure is regulated by the brain, blood vessels, or kidney, but recent evidence suggests it could be regulated in the skin, and sun exposure plays a role in controlling hypertension.[4]
One of the earlier studies of hypertension and sun showed hypertension increased linearly at increasing distances from the equator.[5] One study of hypertensive subjects shows that blood pressure levels average 165/90 in winter but 134/74 in the summer, and both stroke and heart attack rates double in the winter.[6] Even in children, blood pressure is higher in winter than summer.[7] This, of course, is indicative of a protective role of sun exposure on hypertension.
UVB light treatments with sun lamps have also been shown to substantially lower blood pressure in 24 hours, and over six weeks to raise serum 25(OH)D levels of vitamin D by 162%, while lowering both systolic and diastolic pressure by six points.[8]
However, it is important to again mention that there is another important player in the relationship between hypertension and sun. Ultraviolet A (UVA) light (part of sunlight) stimulation of the skin causes the release of nitric oxide (NO) from pre-formed stores of NO in the skin. NO is a potent vasodilator, and when released into the arteries by UVA stimulation, causes increased blood flow and lowered blood pressure.[9], [10]
Safe sun exposure, along with plenty of vegetable and fruit consumption, may enable you to say goodbye to blood-pressure problems.
[1] Mayo Clinic Diseases and Conditions: High blood pressure (hypertension). http://www.mayoclinic.org/diseases-conditions/high-blood-pressure/basics/definition/con-20019580 (accessed January 5, 2016).
[2] Fields LE, Burt VL, Cutler JA, Hughes J, RoccellaEJ, Sorlie P. The burden of adult hypertension in the United States 1999–2000: a rising tide. Hypertension. 2004;44:398–404.
[3] Ann Pietrangelo. Healthline 2014 http://www.healthline.com/health/high-blood-pressure-hypertension/effect-on-body (accessed January 4, 2016).
[4] Johnson RS, Titze J, Weller R. Cutaneous control of blood pressure. Curr Opin Nephrol Hypertens. 2016;Jan25(1):11-5.
[5] Rostand SG. Ultraviolet light may contribute to geographic and racial blood pressure differences. Hypertension. 1997 Aug;30(2 Pt 1):150-6.
[6] Charach G, Rabinovich PD, Weintraub M. Seasonal changes in blood pressure and frequency of related complications in elderly Israeli patients with essential hypertension. Gerontology. 2004 Sep-Oct;50(5):315-21
[7] Polat M, Akil I, Yuksel H, Coskun S, Yilmaz D, Erguder I, Onag A. The Effect of seasonal changes on blood pressure and urine specific gravity in children living in Mediterranean climate. Med Sci Monit2006;12:CR186-90.
[8] Krae R, Bühring M, Hopfenmüller W, Holick MF, Sharma AM. Ultraviolet B and blood pressure. Lancet 1998;352:709-10.
[9] Liu D, Fernandez BO, Hamilton A, Lang NN, Gallagher JM, Newby DE, Feelisch M, Weller RB. UVA irradiation of human skin vasodilates arterial vasculature and lowers blood pressure independently of nitric oxide synthase. J Invest Dermatol. 2014 Jul;134(7):1839-46.
[10] D Liu, BO Fernandez, NN Lang, JM Gallagher, DE Newby, M Feelisch and RB Weller. UVA lowers blood pressure and vasodilates the systemic arterial vasculature by mobilization of cutaneous nitric oxide stores. Photobiology Abstract # 1247 May 2013.
Sun Exposure and health by Marc Sorenson, EdD…
A very interesting study has been completed in a remote area of South America.
An indigenous tribe from the remote Bolivian Amazon jungle, known as the Tsimane, has been found to have the world’s healthiest arteries.[1] People there survive on a diet low in saturated fats and high in non-processed foods. One of the researchers stated that “Our study shows that the Tsimane indigenous South Americans have the lowest prevalence of coronary atherosclerosis of any population yet studied.”
Here are some of the lifestyle habits and facts regarding the Tsimane.
- The diet is fiber rich.
- The diet is approximately 75% non-processed carbohydrates. Isn’t that supposed to make us fat?
- The diet includes rice, plantain (a type of banana), corn, nuts, and a very small amount of animal meat.
- Smoking is almost non-existent.
- Only three per cent of the people had moderate to high heart disease risk; two-thirds of them over 75 years of age had virtually no risk. The article states that only 14% of Americans had no risk, and that half had a moderate or high risk—about 5 times higher than the Tsimane.
- Men spend six to seven hours of their day being physically active, whereas women spend four to six hours. This, of course, means plenty of sun exposure.
During most of my professional career, I have advised people to live on this type of diet, but without the meat or any other animal product. In addition we helped them to exercise several hours daily outside. During that time, my wife and I have observed that people have recovered from diabetes, heart disease, arthritis and other maladies. That is no surprise, considering this new research and many other studies. Vitamin D and nitric oxide, both photoproducts, are exceptionally important to human health, but when it comes to heart disease, nitric oxide is probably the operative photoproduct. Here is a quote from Dr. Richard Weller, a common-sense dermatologist and great researcher:
“Sunlight may have beneficial cardiovascular effects, independently of Vitamin D production. Vitamin D could in these circumstances act as a marker for sunlight exposure and its postulated beneficial effects.” “These recent human data show the physiological relevance of photorelaxation. High blood pressure is the leading cause of disability adjusted life years lost worldwide and as a risk factor underlies 18% of all deaths.” The study noted: “The action spectrum of nitrite release shows that ultraviolet B is also involved in nitrite reduction to Nitric Oxide, and thus sunlight may be more effective than a pure UVA source.” The study concluded: “the prevalence of cardiovascular and cerebrovascular deaths is around 100 times higher than those from skin cancer. Interventions leading to small changes in the incidence of cardiovascular disease are thus of greater benefit to the health of the public even than large changes in skin cancer incidence.”[2]
The Tsimane, therefore, are living (unknowingly) an almost perfect lifestyle for optimal health. To stay well, it is imperative that we do the same, although we don’t need quite that much sun exposure. Remember to build up a tan and be safe in the sun.
[1] http://www.mirror.co.uk/science/proof-modern-life-really-kill-10047382
[2] Weller R. The health benefits of UV radiation exposure through vitamin D production or non-vitamin D pathways. Blood pressure and cardiovascular disease. Photochem. Photobiol. Sci. 2016, DOI: 10.1039/C6PP00336B.
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 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. https://lifesciencedaily.com/stories/19743-study-shows-health-benefits-non-burning-exposure-uv-light/
By Marc Sorenson, EdD. Sunlight Institute… promoting safe sun exposure…
It has long been known that vitamin D deficiency is associated with hypertension. But could that association really be a measurement of inadequate sun exposure? A most interesting investigation was carried out this month (July 2016) in which the researchers evaluated over 1100 subjects from an ongoing study called “the Reasons for Racial and Geographic Differences in Stroke.” They measured vitamin D levels and also assessed sun exposure levels, and found that both high vitamin D levels and high sun exposure levels were associated with higher blood pressure.[1]
What makes this research different is that when the data was adjusted for other factors, high sun exposure was even more impressive as a protective factor against high blood pressure. However, adjusting for vitamin D levels had no effect on the association of sun exposure to lower blood pressure; for each increase in sun exposure, there was a corresponding decrease in blood pressure, but the same was not true for increases or decreases in vitamin D levels.
The researchers made this statement: “We conclude that although 25(OH)D concentration is inversely associated with SBP, it did not explain the association of greater sunlight exposure with lower BP.”
To me, this research indicates that sun exposure directly effects lower blood pressure levels, independently of vitamin D. This is not surprising, since clinical trials of vitamin D supplementation have found only small effects on blood pressure.[2]
I hypothesize that nitric oxide (NO), is the mechanism by which sun exerts its impressive effects. NO is a potent vasodilator, and when it is released into the arteries by UVA stimulation, causes increased blood flow and lowers blood pressure.[3] [4] Dr. Oplander and his colleagues wrote the first paper on the UVA, NO and blood pressure in 2009,[5] and Dr. Richard Weller has been a leader in doing research and granting interviews on NO since that time. He has made two interesting statements: (1) “We suspect that the benefits to heart health of sun will outweigh the risk of skin cancer. The work we have done provides a mechanism that might account for this, and also explains why dietary vitamin D supplements alone will not be able to compensate for lack of sun.”[6] (2) “Although the benefits of sun are often attributed to vitamin D, a gas called nitric oxide is also important. Made when the sun hits our skin, nitric oxide lowers blood pressure when it enters the bloodstream. Although the reduction is small, it could ‘make a big difference.”[7]
A study from China also demonstrates that exposure to sun correlates to a lowered risk of hypertension.[8] In a randomly selected population of Chinese residents from Macau (where the rate of hypertension is very high), the following risk factors for hypertension were assessed: lack of sun exposure, low intake of fish, smoking, obesity and lack of exercise. An average of more than one-half hour of sun exposure per day compared to none predicted a 40% reduced risk for hypertension.
Vitamin D has many marvelous health effects, but sun exposure per se has many more, because not only does the sun stimulate the production on vitamin D, it also produces other vital photoproducts such as NO, endorphins and serotonin. When we avoid the sun and simply take a vitamin D pill, we are short-changing ourselves for the total package of benefits derived from the sun. And in the case of high blood pressure, we may be receiving almost no benefit from vitamin D. Think about it, and enjoy the sun safely.
[1] Rostand SG, McClure LA, Kent ST, Judd SE, Gutiérrez OM. Associations of blood pressure, sunlight, and vitamin D in community-dwelling adults. J Hypertens. 2016 Jul 1. [Epub ahead of print]
[2] Beveridge LA, Struthers AD, Khan F, Jorde R, Scragg R, Macdonald HM, Alvarez JA, Boxer RS. Et. al. Effect of Vitamin D Supplementation on Blood Pressure: A Systematic Review and Meta-analysis Incorporating Individual Patient Data. AMA Intern Med. 2015 May;175(5):745-54.
[3] Liu D, Fernandez BO, Hamilton A, Lang NN, Gallagher JM, Newby DE, Feelisch M, Weller RB. UVA irradiation of human skin vasodilates arterial vasculature and lowers blood pressure independently of nitric oxide synthase. J Invest Dermatol. 2014 Jul;134(7):1839-46.
[4] D Liu, BO Fernandez, NN Lang, JM Gallagher, DE Newby, M Feelisch and RB Weller. UVA lowers blood pressure and vasodilates the systemic arterial vasculature by mobilization of cutaneous nitric oxide stores. Photobiology Abstract # 1247 May 2013.
[5] Opländer C, Volkmar CM, Paunel-Görgülü A, van Faassen EE, Heiss C, Kelm M, Halmer D, Mürtz M, Pallua N, Suschek CV.. Whole body UVA irradiation lowers systemic blood pressure by release of nitric oxide from intracutaneous photolabile nitric oxide derivates. Circ Res. 2009;105:1031–40.
[6] Quoted on Mercola.com http://articles.mercola.com/sites/articles/archive/2013/07/15/sun-exposure.aspx accessed July 2, 2015.
[7] Weller, R. Shunning the sun may be killing you in more ways than you think. New Scientist July 2, 2015.
[8] Ke L, Ho J, Feng J, Mpofu E, Dibley MJ, Feng X, Van F, Leong S, Lau W, Lueng P, Kowk C, Li Y, Mason RS, Brock KE. Modifiable risk factors including sun exposure and fish consumption are associated with risk of hypertension in a large representative population from Macau. J Steroid Biochem Mol Biol 2013 Nov 1 [Epub ahead of print].
By Marc Sorenson, EdD Sunlight Institute…
A most interesting research paper demonstrates that nitrate supplements, combined with exposure to sunlight, increases performance of cyclists.[1] The researchers state that “dietary nitrate supplementation has been shown to increase nitric oxide (NO) metabolites, reduce blood pressure (BP) and enhance exercise performance.” And, as we have discussed in this blog, sun exposure reduces BP by increasing the production of NO. It was theorized that sun exposure might enhance the athletic performance induced by the dietary nitrate supplementation.
The theory proved to be correct; although sun exposure did not improve cycling times by itself, when combined with the nitrate supplementation, cycling times improved significantly.
It may surprise some people to realize that ultraviolet radiation (UVR) from sun beds or sun lamps has been used since before 1950 to enhance athletic performance.[2] As early as 1938, Russian researchers reported that a course of UVR significantly improved speed in the 100-meter dash among four students when compared with controls that did not have the radiation, although both groups were undergoing identical daily training.[3] The non-irradiated group improved by 1.7% but the irradiated group improved by 7.4%. Another study conducted over ten weeks showed that cardiovascular endurance improved remarkably among athletes in training who were irradiated vs. those who were not.[4] The irradiated athletes improved by 19.2% compared to 1.5% among the non-irradiated group.
There are numerous studies from Germany showing the efficacy of UVR on athletic performance, most of them from the early days before the idea of sun-lamp produced UVR fell into disrepute because of the attack on tanning beds. What a shame. This method of athletic assistance could produce an impressive improvement in sports performance for so many people, athletic or not. Strength improves, stamina improves, quickness improves and speed improves with UVR radiation, which of course is also part of sunlight. The mechanism for this improvement is likely a combination of vitamin D and nitric oxide.
Safely enjoy the sun!
[1] Muggeridge DJ, Sculthorpe N, Grace FM, Willis G, Thornhill L, Weller RB, James PE, Easton C. Acute whole body UVA irradiation combined with nitrate ingestion enhances time trial performance in trained cyclists. Nitric Oxide. 2015 Aug 1;48:3-9.
[2] Cannell JJ, Hollis BW, Sorenson MB, Taft TN, Anderson JJ. Athletic performance and vitamin D. Med Sci Sports Exerc. 2009 May;41(5):1102-10.
[3] Gorkin Z. Gorkin MJ, Teslenko NE. The effect of ultraviolet radiation upon training for the 100-meter sprint.
[4] Allen R, Cureton T. Effects of ultraviolet radiation on physical fitness. Arch Phys Med 1945;10:641-4.
From Science Daily, research is reported on the ability of sunlight exposure to effectively lower blood pressure.[i] The research, reported earlier by Dr. Richard Weller, is not really new, but it is good to see that it is receiving more press. Even more important is the fact that Dr. Weller is a dermatologist. The study was conducted by exposing the skin of 24 healthy volunteers to ultraviolet light from tanning lamps for two sessions of 20 minutes each. In one session, they were exposed to both ultraviolet A (UVA) and the heat from the lamps; in another, the UVA rays were blocked so that only the heat was applied. Blood pressure was lowered by UVA exposure, but not by heat alone.
It has been known for some time that nitric oxide (NO) is produced by the skin in response to sunlight. NO is a potent vasodilator that relaxes the vessels and allows blood pressure to drop. Therefore, the sunlight, or tanning lamps, both of which emit UBA, become useful tools for lowering blood pressure.
It is important to note that these results were achieved with no increase in vitamin D levels. Therefore, sunlight stands on its own in reducing blood pressure. This is not to negate the positive influence of vitamin D; it is a critical factor in reducing the risk of myriad diseases. My ongoing searches of the medical and scientific literature, however, have persuaded me that most studies that assess the influence of sunlight alone are more impressive in preventing disease than those that assess only vitamin D blood levels or supplementation.
Dr. Feelisch, one of the investigators, stated the following: “These results are significant to the ongoing debate about potential health benefits of sunlight and the role of Vitamin D in this process. It may be an opportune time to reassess the risks and benefits of sunlight for human health and to take a fresh look at current public health advice. Avoiding excess sunlight exposure is critical to prevent skin cancer, but not being exposed to it at all, out of fear or as a result of a certain lifestyle, could increase the risk of cardiovascular disease.”
More on this subject will follow. In the meantime, allow yourself safe, non-burning exposure to the sun.
[i] University of Southampton (2014, January 17). Here comes the sun to lower your blood pressure. Science Daily. Retrieved January 18, 2014, from http://www.sciencedaily.com /releases/2014/01/140117090139.htm.
In the last post, I made the point that sunlight, through the stimulation of nitric oxide (NO) production in the skin, created a vasodilating effect in healthy volunteers that led to lower blood pressure. It was also noted that the effect of sunlight on blood pressure was not due to vitamin D production and circulation, since there was no change in vitamin D levels during the investigation.
High blood pressure is also known as hypertension, and a recent study from China demonstrates that exposure to sunlight correlates to a lowered risk of that disease.[1] In a randomly selected population of Chinese residents from Macau (where the rate of hypertension is very high), the following risk factors for hypertension were assessed: lack of sunlight exposure, low intake of fish, smoking, obesity and lack of exercise. An average of more than one-half hour of sunlight exposure per day compared to none predicted a 40% reduced risk for hypertension. Oily fish consumption more than four times per week predicted a 60% reduced risk; daily moderate physical activity compared to no physical activity predicted a 20% reduced risk; being obese compared to normal weight predicted 4.6 times the risk of hypertension, and heavy smoking predicted 1.4 times the risk.
Hypertension is a major risk factor for heart and other vascular diseases, which are the number-one killers in western societies. Isn’t it time we made a few lifestyle changes that could profoundly reduce the risk of these diseases? The efforts to Frighten people out of the sunlight, coupled with the move to indoor living, have created unquestionable health disasters. We need to once again learn to enjoy safe, non-burning sun exposure.
[1] Ke L, Ho J, Feng J, Mpofu E, Dibley MJ, Feng X et al. Modifiable risk factors including sunlight exposure and fish consumption are associated with risk of hypertension in a large representative population from Macau. J Steroid Biochem Mol Biol 2013 Nov 1 [Epub ahead of print].