Posted on 04/07/2010 10:30:22 AM PDT by decimon
Women living in the northeastern United States are more likely to develop rheumatoid arthritis (RA), suggesting a link between the autoimmune disease and vitamin D deficiency, says a new study led by a Boston University School of Public Health researcher.
In the paper, which appears online in the journal Environmental Health Perspectives, a spatial analysis led by Dr. Verónica Vieira, MS, DSc, associate professor of environmental health, found that women in states like Vermont, New Hampshire and southern Maine were more likely to report being diagnosed with RA.
"There's higher risk in the northern latitudes," Dr. Vieira said. "This might be related to the fact that there's less sunlight in these areas, which results in a vitamin D deficiency."
The study looked at data from the Nurses' Health Study, a long-term cohort study of U.S. female nurses. Looking at the residential addresses, health outcomes and behavioral risk factors for participants between 1988 and 2002, researchers based their findings on 461 women who had RA, compared to a large control group of 9,220.
RA is a chronic inflammatory disease that affects the lining of the joints, mostly in the hands and knees. This chronic arthritis is characterized by swelling and redness and can wear down the cartilage between bones. RA is two to three times more common in women than in men.
Although the cause of RA is unknown, the researchers wrote, earlier studies have shown that vitamin D deficiency, which can be caused by a lack of sunlight, has already been associated with a variety of other autoimmune diseases.
"A geographic association with northern latitudes has also been observed for multiple sclerosis and Crohn's disease, other autoimmune diseases that may be mediated by reduced vitamin D from decreased solar exposure and the immune effects of vitamin D deficiency," the authors wrote.
The authors said further research is needed to look into the relationship between vitamin D exposure and RA.
Dr. Vieira said she and her co-authors were somewhat surprised by the findings. A previous geographic study of RA had suggested an ecologic association with air pollution, she said.
"The results were unexpected," Dr. Vieira said. "Prior to the analysis, we were more interested in the relationship with air pollution. I hadn't given latitudes much thought."
In addition to the geographic variation, the study suggested that the timing of residency may influence RA risk. "Slightly higher odds ratios were observed for the 1988 analysis suggesting that long term exposure may be more important than recent exposure," the study said.
Dr. Vieira and other BUSPH researchers previously have used innovative spatial-temporal analyses to study the incidence of breast cancer, specifically focused on Cape Cod.
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In addition to Dr. Vieira, co-authors of the article are Dr. Jaime Hart, MS, ScD, research fellow, Department of Epidemiology, Harvard School of Public Health; Dr. Thomas Webster, DSc, professor and associate chair, Department of Environmental Health, Boston University School of Public Health; Dr. Janice Weinberg, ScD, MS, associate professor, Department of Biostatistics, Boston University School of Public Health; Dr. Robin Puett, PhD, MPH, research assistant professor, Environmental Health Sciences, University of South Carolina; Dr. Francine Laden, ScD, MS, associate professor, Department of Epidemiology, Harvard School of Public Health; Dr. Karen Costenbader, MD, assistant professor of medicine, Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital and Harvard Medical School; and Dr. Elizabeth Karlson, MD, associate professor of medicine, Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital and Harvard Medical School.
The research was funded by grants from the National Institutes of Health.
The full study can be accessed online. (link: http://ehsehplp03.niehs.nih.gov/article/fetchArticle.action?articleURI=info%3Adoi%2F10.1289%2Fehp.0901861)
Submitted by Elana Zak ezak@bu.edu
BUSPH’s fault ping.
Beat me to it. Darn you! :D
We try to get 15-20 minutes of un-sunblocked sun a day. It boosts the immune system also. Even my 18 month old son goes out without sun-block. It was shown to be very effective during the swine flu “epidemic”.
hmm....how ‘bout the people with RA who spent most of their lives living in sunny states and spending a lot of time outdoors?
I feel a global warming connection in my bones.
It’s also possible that some bodies do not use vitamin d very efficiently.
“hmm....how ‘bout the people with RA who spent most of their lives living in sunny states and spending a lot of time outdoors?”
My aunt came out here from Florida, she had arthritis very bad. She came to Arizona and after 6 months it went away, I wonder if it had to do more with the humidity back east. Out here our humidity is like 12%.
If they are using sunscreen the sun won’t do a thing for them.
‘It’s also possible that some bodies do not use vitamin d very efficiently. ‘
True, but that’s not what the article says, it says, “reduced vitamin D from decreased solar exposure”.
Interestingly, RA was not described in European populations prior to 1780, and its stigmata is not found in medieval or ancient skeletons. It is seen in North American Pre-Colombian skeletons, and is thought therefore to have been transmitted from the New to the Old World. So, RA is a lot more than just insufficient Vitamin D.
Also...””A geographic association with northern latitudes has also been observed for multiple sclerosis and Crohn’s disease, other autoimmune diseases that may be mediated by reduced vitamin D from decreased solar exposure and the immune effects of vitamin D deficiency,” the authors wrote. “
Although there has been some link between rates of MS and northern latitudes (higher incidences in Minnesota, for instance), it certainly doesn’t explain the higher numbers in Colorado, which gets over 300 days of sunshine a year.
“We try to get 15-20 minutes of un-sunblocked sun a day.”
In Ohio we do not get enough sun exposure, and the 14-20 minutes a day is still not enough to raise D to levels we need. D3 (like we get from the sun) is easy to supplement, and we should all supplement a minimum of 10,000 iu per day (my opinion, shared by medical doctors who are doing as much as 50,000 iu per day themselves).
D3 does boost immune response. D3 is preventative regarding colds and flu. Flu season is winter months - less D from sun exposure.
Dark skin absorbs even less of the sun’s rays that make D in the skin. Dark skinned people tend to be much more deficient than light skinned people.
We’ve long known that healthy Vitamin D levels are related to strong bones, but several recent peer-reviewed scientific studies have clearly shown that Vitamin D also decreases our risk of getting overweight and developing high blood presure, diabetes, heart disease, arthritis, cancer, and other health problems.
Think twice before applying that sunscreen! Did you know vitamin D deficiency kills more than one million people each year? As more and more people slather on the sunscreen (which is most likely filled with harmful and toxic chemicals), they get less and less of nature’s “sunshine” vitamin, which is synthesized by the skin when exposed to direct sunlight. On the flip side, the risk of being harmed by the sun is minimal. Sufficient vitamin D levels can decrease a woman’s breast cancer risk by 50 percent, and suppress tumor growth in colorectal, breast and prostate cancer.
I’m in Ohio and I think we’re getting enough D. It’s not easy, but we go outside whenever we can! We use chemical-free sunblock. I don’t like the ingredients in the regular stuff. Our current fave is Burt’s Bees.
At the latitude of Boston there are four months of the year when you can't make any vitamin D from sunlight. Somewhere in S. Carolina is where you can year round. You pretty much have to be in the sunlight in the middle of the day to make vitamin D, during those months that it's possible to make vitamin D from sunlight. And with good skin exposure.
Conclusions: Spatial analyses suggest women living in higher latitudes may be at greater risk for RA. Further, RA risk may be greater for locations occurring earlier in residential histories. These results illustrate the usefulness of GAM methods in generating hypotheses for future investigation and supporting existing hypotheses.GAM methods are generalized additive models for generating epidemiological hypotheses.
The meaning is obscure to me. The link didn't help.
That is interesting. I’ve always heard “the old folks” say that damp weather made their “rheumatism act up”. Some used to say they could tell when the weather was going to change by the way they felt.
"The meaning is obscure to me. The link didn't help."
Sunlight deprivation and consequent vitamin D deficiency might be more easily explained by getting a complete history of where a person lived, not just where they are currently living.
Okay, thanks.
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