Health studies about sunlight and cancer:
Association Between Ultraviolet Radiation, Skin Sun Sensitivity and Risk of Pancreatic Cancer (2013)
Conclusion: “Being born in or living in areas of higher ambient UVR [ultraviolet radiation] (compared to lower ambient UVR) was associated with about 30-40% lower risk of pancreatic cancer. People with fair skin colour had 47% lower risk of pancreatic cancer than those with dark skin colour (95% CI 0.37-0.75). There was some suggestion of increased risk with increased average number of hours spent outside at work. This study suggests that people with light skin colour or those born or living in areas of high ambient UVR have lower risk of pancreatic cancer. Our analysis supports an association between UVR and pancreatic cancer, possibly mediated through production of vitamin D.”
Is Prevention of Cancer by Sun Exposure More Than Just the Effect of Vitamin D? A Systematic Review of Epidemiological Studies (2013)
Conclusion: “We found that almost all epidemiological studies suggest that chronic (not intermittent) sun exposure is associated with a reduced risk of colorectal-, breast-, prostate cancer and NHL.”
Note: This article covers many studies providing strong evidence that a lack of UVB exposure / vitamin D is strongly associated with colon cancer, rectal cancer, breast cancer, gastric cancer, non-Hodgkin’s lymphoma, Hodgkin’s lymphoma, bladder cancer, ovarian cancer, pancreatic cancer, esophageal cancer, lung cancer, cervical cancer, renal cancer, vulvar cancer, gallbladder cancer, brain cancer, multiple myeloma, leukemia, prostate cancer, laryngeal cancer, thyroid cancer, melanoma, and pharyngeal cancer.
Conclusion: 995 esophageal cancer patients in Australia were analyzed along with 1471 population controls. The cancer patients reported having less sun exposure over their lifetimes and tended to live in less sunny areas than the controls.
Conclusion: 1,500 ovarian cancer patients and 1,459 healthy female controls in Australia were analyzed. The top third of all the women who reported having the most sun exposure over their lifetimes and who lived in the sunnier areas of Australia had the lowest risk for ovarian cancer. Those in the bottom third for lifetime sun exposure had the highest risk for ovarian cancer. “Women who spent their lives in areas with higher levels of ambient UVR [ultraviolet radiation] had a lower risk of developing epithelial ovarian cancer than those living in areas with lower levels of ambient UVR.”
Vitamin D and Cancer (2012)
Conclusion: “In clinical studies, an impact of vitamin D has been reported in different types of cancer. A low vitamin D activity is associated with an increased cancer risk and a more aggressive tumor growth, while high activity of this pathway induces antitumoral effects. In particular, serum circulating levels of 25(OH)D levels <20 ng/ml seems to expose to the risk of developing mammary and colorectal cancer.”
Exposure to Ultraviolet Radiation: Association with Susceptibility and Age at Presentation with Prostate Cancer (2011)
Conclusion: “A positive association between latitude and prostate cancer mortality has been interpreted to indicate that ultraviolet radiation (UVR) protects against development of this cancer.”
Increased UVA Exposures and Decreased Cutaneous Vitamin D3 Levels May Be Responsible for the Increasing Incidence of Melanoma (2009)
Conclusion: Low vitamin D levels resulting from a lack of direct, midday sun exposure increase the risk of developing melanoma skin cancer
Note: Comprehensive overview on the evidence of vitamin D and UVB’s anti-cancer benefits.
Conclusion: Although UVB exposure can cause non-melanoma skin cancer, it’s also the same UV spectrum necessary for the epidermal vitamin D synthesis that prevents other cancers.
Sun Exposure Prior to Diagnosis is Associated with Improved Survival in Melanoma Patients: Results from a Long-Term Follow-Up Study of Italian Patients (2008)
Conclusion: Melanoma skin cancer patients who enjoy more sun exposure over their lifetimes also enjoy higher survival rates
Conclusion: Individuals who achieve adequate vitamin D levels through supplementation and moderate sun exposure are 50% less likely to develop breast cancer compared to individuals who test as being deficient in vitamin D
Conclusion: Increasing sun exposure reduces breast cancer risk.
Solar ultraviolet-B exposure and cancer incidence and mortality in the United States, 1993-2002 (2006)
Conclusion: For the period of 1993 to 2002, satellite-measured solar UV-B levels, 3+ million cancer incidences, and 3 million cancer deaths in America were analyzed. There was a correlation between lower UVB levels and an increased rate of “bladder, colon, Hodgkin lymphoma, myeloma, prostate, rectum, stomach, uterus, and vulva” cancer, and to a lesser extent for “breast, kidney, leukemia, non-Hodgkin lymphoma, pancreas, and small intestine” cancer.
Conclusion: “From our review, it becomes clear that there is an increasing evidence of sunlight having a preventive effect on the initiation and/or progression of different kinds of cancer.”
Conclusion: Sun exposure and vitamin D prevent colon, breast, prostate, and ovarian cancer
The Association of Solar Ultraviolet B (UVB) with Reducing Risk of Cancer: Multifactorial Ecologic Analysis of Geographic Variation in Age-Adjusted Cancer Mortality Rates (2006)
Conclusion: A study of American cancer mortality rates from 1950-1969 and 1970-1994 found that cancer mortality rates have been higher in areas of American with weaker UVB solar radiation (i.e. northern latitudes).
Conclusion: Study examined 551 people with non-hodgkin lymphoma and 462 controls and found that those who received more UV exposure through sunlight and tanning lamps had a slightly reduced risk for NHL.
Conclusion: Within the U.S., the states with the highest amount of solar radiation (New Mexico, Arizona, Florida, California, Texas – low latitudes) have the lowest rates of colon cancer mortality and the states with the lowest solar radiation (New York, New Jersey, Rhode Island, Connecticut – high latitudes) have the highest rates of colon cancer mortality. Lower latitude populations tend to have higher vitamin D levels than higher latitude populations.
Conclusion: “Sun exposure is associated with increased survival from melanoma.”
Conclusion: Outdoor workers are at a lower risk of developing melanoma skin cancer compared to indoor workers.
Conclusion: 115,096 cases of breast, colon, and prostate cancer diagnosed over a 28-year period were observed. Researchers found that patients diagnosed in the summer and fall, when population vitamin D levels are highest, had the lowest cancer fatality rate. “The results suggest that a high level of vitamin D3 at the time of diagnosis, and thus, during cancer treatment, may improve prognosis of the three cancer types studied.” The study also found that men and women who received medium to high levels of occupational sun exposure had an extraordinarily lower cancer fatality rate compared to people with low occupational sun exposure.
The Influence of Painful Sunburns and Lifetime Sun Exposure on the Risk of Actinic Keratoses, Seborrheic Warts, Melanocytic Nevi, Atypical Nevi, and Skin Cancer (2003)
Conclusion: While chronic lifetime sun exposure is associated with an increased risk for non-melanoma skin cancer, lifetime sun exposure is also associated with a decreased risk for deadly melanoma skin cancer
An Estimate of Premature Cancer Mortality in the U.S. Due to Inadequate Doses of Solar Ultraviolet-B Radiation (2002)
Conclusion: Lack of midday sun exposure increases one’s risk for developing and dying from breast, colon, ovarian, prostate, bladder, esophageal, kidney, lung, pancreatic, rectal, stomach, and uterine cancer.
Sunlight and Mortality From Breast, Ovarian, Colon, Prostate, and Non-Melanoma Skin Cancer: A Composite Death Certificate Based Case-Control Study (2002)
Conclusion: Sun exposure lowers your risk of developing breast, ovarian, prostate, and colon cancer
Prostate Cancer Risk: Associations With Ultraviolet Radiation, Tyrosinase and Melanocortin-1 Receptor Genotypes (2001)
Conclusion: “Exposure to ultraviolet radiation may reduce prostate cancer risk”
Conclusion: “Sunlight exposure and dietary vitamin D reduce the risk of breast cancer.”
Conclusion: “Sunlight may be a protective factor for ovarian cancer mortality.”
Conclusion: “The research studies presented here suggest that dermal activation of vitamin D from regular, moderate sun exposure has a strong protective effect in the prevention of breast and colon cancer; has a weaker protective effect in melanoma, leukemia, and lymphoma; and acts to lower overall cancer death rates.”
Geographic Patterns of Prostate Cancer Mortality. Evidence for a Protective Effect of Ultraviolet Radiation (1992)
Conclusion: There are lower prostate cancer mortality rates in the southern regions of America compared to the northern regions due to the south receiving stronger sunlight with more vitamin D-producing UVB radiation.
Geographic Variation in Breast Cancer Mortality in the United States: A Hypothesis Involving Exposure to Solar Radiation (1990)
Conclusion: The U.S. breast cancer mortality rate is lower in the South and Southwest regions of America (which are closer to the equator and get more UVB) than it is in the Northeast (farther away from the equator, less UVB)
Conclusion: Navy personnel who work indoors have an increased incidence of melanoma skin cancer compared to personnel who work outdoors.
Conclusion: Sun exposure increases immunity to cancer