Posted on 10/21/2007 7:24:44 PM PDT by blam
Exposure To Sunlight May Decrease Risk Of Advanced Breast Cancer By Half
ScienceDaily (Oct. 21, 2007) — A research team from the Northern California Cancer Center, the University of Southern California, and Wake Forest University School of Medicine has found that increased exposure to sunlight -- which increases levels of vitamin D in the body -- may decrease the risk of advanced breast cancer.
In a study reported in the American Journal of Epidemiology, the researchers found that women with high sun exposure had half the risk of developing advanced breast cancer, which is cancer that has spread beyond the breast, compared to women with low sun exposure. These findings were observed only for women with naturally light skin color. The study defined high sun exposure as having dark skin on the forehead, an area that is usually exposed to sunlight.
The scientists used a portable reflectometer to measure skin color on the underarm, an area that is usually not directly exposed to sunlight. Based on these measurements, they classified the women as having light, medium or dark natural skin color. Researchers then compared sun exposure between women with breast cancer and those without breast cancer. Sun exposure was measured as the difference in skin color between the underarm and the forehead.
In women with naturally light skin pigmentation, the group without breast cancer had significantly more sun exposure than the group with breast cancer. The fact that this difference occurred only in one group suggests that the effect was due to differences in vitamin D production -- and wasn't just because the women were sick and unable to go outdoors. In addition, the effect held true regardless of whether the cancer was diagnosed in the summer or in the winter. The difference was seen only in women with advanced disease, suggesting that vitamin D may be important in slowing the growth of breast cancer cells.
"We believe that sunlight helps to reduce women's risk of breast cancer because the body manufactures the active form of vitamin D from exposure to sunlight," said Esther John, Ph.D., lead researcher on the study from the Northern California Cancer Center. "It is possible that these effects were observed only among light- skinned women because sun exposure produces less vitamin D among women with naturally darker pigmentation."
These new findings about breast cancer risk and sun exposure based on skin color measurements are consistent with previous research by John and colleagues that had shown that women who reported frequent sun exposure had a lower risk of developing breast cancer than women with infrequent sun exposure.
The researchers stressed that sunlight is not the only source of vitamin D, which can be obtained from multivitamins, fatty fish and fortified foods such as milk, certain cereals and fruit juices. Women should not try to reduce their risk of breast cancer by sunbathing because of the risks of sun-induced skin cancer, they said.
"If future studies continue to show reductions in breast cancer risk associated with sun exposure, increasing vitamin D intake from diet and supplements may be the safest solution to achieve adequate levels of vitamin D," said Gary Schwartz, Ph.D., a co-researcher from the Comprehensive Cancer Center at Wake Forest University School of Medicine.
"Since many risk factors for breast cancer are not modifiable, our finding that a modifiable factor, vitamin D, may reduce risk is important," said Sue Ingles, Ph.D., a co-researcher from University of Southern California Keck School of Medicine.
The researchers compared 1,788 breast cancer patients in the San Francisco Bay area with a matched control group of 2,129 women who did not have breast cancer. They included non-Hispanic white,
Hispanic and African-American women, thus women with a wide range of natural skin color and a wide range of capacity to produce vitamin D in the body. Skin color is an important factor that determines how much vitamin D is produced in the body after sun exposure. Dark-skinned individuals produce up to 10 times less vitamin D than light-skinned individuals for the same amount of time spent in the sun. People with darker skin are also more likely to be vitamin D deficient than people with lighter skin.
The research team also included Wei Wang, Ph.D., of the University of Southern California Keck School of Medicine. The work was supported by grants from the National Cancer Institute and U.S. Department of Defense Medical Research Program.
Adapted from materials provided by Wake Forest University Baptist Medical Center.
I heard you also needed it fight immune disorders such as MS.
I am so pale that, on a southern beach, I am covered in freckles in ten minutes, wearing SPF 50 and a hat.
When I did try to tan, people always asked when I was going to tan. I am tan, I said, showing the underside of my arm. You are a ghost, they said.
A few hours of sun and wind puts 15 years on me.
I get my Vitamin D from pills, thank you very much. Family history of breast cancer, but I figure 10+ years of breastfeeding is good for something.
Here’s what I don’t understand: if this is true, then why didn’t every single Victorian lady get breast cancer? Because of course they covered themselves from head to toe, never sunbathed, rarely engaged in outdoors sports, and kept even their arms and hands white by covering them with long sleeves and gloves. Doubt they could have eaten much salmon to get Vitamin D, either. This study would have been more interesting if the results had been cross-correlated with the number of abortions each woman had.
They probably ingested cod liver oil.....or an equivalent....
You don’t need high dosages.
Colon cancer also linked to sunlight/Vitamin D deficiency:
“The geographic distribution of colon cancer is similar to the historical geographic distribution of rickets. The highest death rates from colon cancer occur in areas that had high prevalence rates of rickets—regions with winter ultraviolet radiation deficiency,”
http://www.ncbi.nlm.nih.gov/sites/entrez?db=pubmed&uid=10668487&cmd=showdetailview&indexed=google
You beat me to it.
Yup. I remember my mom taking it when I was a kid, and, giving it to me when I got the sniffles.
I’ve read that people with skin cancer don’t usually get other types of cancers.
I could guess and say that even if they never went outside, women living then were exposed to more sunlight than you might think.
Houses built back then had many more windows than they do now, to admit air and light from outside. Houses built now have fewer windows, for reasons of security, cost, and energy efficiency. Ventilation and lighting are electric now, so windows are unnecessary.
i don’t believe you, you must post pics.
on a less serious note, are you British or from the Irish Isles? many of the ladies from those regions have absolutely no tolerensce for exposure to sunlight. my lite skinned slavic friends in similar areas have few such problems.
The average age of menarche for that era was 17. Childbearing was likely to start within a couple years, with most women having many babies. And the average age of death was much lower. Women didn’t have time to get cancer.
That still doesn’t explain why ancient maiden ladies then didn’t have high BRCA rates, and ancient nuns now do.
The author Fanny Burney endured a total mastectomy in 1811, and survived another 29 years.
...and what other such areas are you suggesting be exposed, eh MOON MAN?
American mutt here - British, German and Swedish mixed. I’ve been to Sweden - was lighter than most.
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