Featured Research

from universities, journals, and other organizations

Sunlight may help ward off rheumatoid arthritis in women

Date:
February 4, 2013
Source:
BMJ-British Medical Journal
Summary:
Regular exposure to sunlight -- specifically ultraviolet B -- may reduce the risk of developing rheumatoid arthritis, indicates a large long-term study.

Regular exposure to sunlight -- specifically ultraviolet B (UVB) -- may reduce the risk of developing rheumatoid arthritis, indicates a large long term study published online in the Annals of the Rheumatic Diseases.

Related Articles


But the effect of UVB exposure was only evident among older women, possibly because younger women are more aware of the hazards of sunlight and so cover up with sun block, suggest the authors.

They base their findings on participants in two phases of the US Nurses' Health Study (NHS), the first of which has tracked the health of more than 120,000 nurses since 1976, when they were aged between 30 and 55, until 2008.

The second (NHSII) has tracked the health of a further 115,500 nurses since 1989, when they were aged between 25 and 42, until 2009.

Rather than simply relying on geography to quantify likely levels of UVB exposure, the researchers used a more sensitive assessment, known as UV-B flux, which is a composite measure of UVB radiation, based on latitude, altitude, and cloud cover.

It is measured in R-B units: a count of 440 R-B units over 30 minutes, for example, is sufficient to produce slight redness in untanned white skin.

Exposure was then estimated according to the US state of residence, and ranged from an annual average of 93 in Alaska and Oregon to 196 in Hawaii and Arizona. Likely estimates of UV exposure at birth and by the age of 15 were also included.

Over the study period, 1314 women developed rheumatoid arthritis. Among nurses in the first NHS cohort, higher cumulative exposure to UVB was associated with a reduced risk of developing the disease.

Those with the highest levels of exposure were 21% less likely to develop rheumatoid arthritis than those with the least, the analysis showed.

This backs up the findings of other studies, showing a link between geography and the risk of rheumatoid arthritis as well as other autoimmune conditions, including type 1 diabetes, inflammatory bowel disease, and multiple sclerosis, say the authors.

But no such association for UV-B exposure was found among women in NHSII. These women were younger than those in the first NHS, and so might have been more savvy about the potential hazards of acquiring a tan, suggest the authors.

"Differences in sun protective behaviours (eg greater use of sun block in younger generations) may explain the disparate results," they explain.

They add that it is unclear at what stage of life the protective effect of UV-B occurs. Many of the study participants didn't move house between birth and their teens, and there was no difference in the results for these time points.

But they conclude: "Our study adds to the growing evidence that exposure to UV-B light is associated with decreased risk of rheumatoid arthritis. The mechanisms are not yet understood, but could be mediated by the cutaneous production of vitamin D and attenuated by use of sunscreen or sun avoidant behaviour."


Story Source:

The above story is based on materials provided by BMJ-British Medical Journal. Note: Materials may be edited for content and length.


Journal Reference:

  1. E. V. Arkema, J. E. Hart, K. A. Bertrand, F. Laden, F. Grodstein, B. A. Rosner, E. W. Karlson, K. H. Costenbader. Exposure to ultraviolet-B and risk of developing rheumatoid arthritis among women in the Nurses' Health Study. Annals of the Rheumatic Diseases, 2013; DOI: 10.1136/annrheumdis-2012-202302

Cite This Page:

BMJ-British Medical Journal. "Sunlight may help ward off rheumatoid arthritis in women." ScienceDaily. ScienceDaily, 4 February 2013. <www.sciencedaily.com/releases/2013/02/130204184535.htm>.
BMJ-British Medical Journal. (2013, February 4). Sunlight may help ward off rheumatoid arthritis in women. ScienceDaily. Retrieved December 22, 2014 from www.sciencedaily.com/releases/2013/02/130204184535.htm
BMJ-British Medical Journal. "Sunlight may help ward off rheumatoid arthritis in women." ScienceDaily. www.sciencedaily.com/releases/2013/02/130204184535.htm (accessed December 22, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Monday, December 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Touch-Free Smart Phone Empowers Mobility-Impaired

Touch-Free Smart Phone Empowers Mobility-Impaired

Reuters - Innovations Video Online (Dec. 21, 2014) A touch-free phone developed in Israel enables the mobility-impaired to operate smart phones with just a movement of the head. Suzannah Butcher reports. Video provided by Reuters
Powered by NewsLook.com
Earthworms Provide Cancer-Fighting Bacteria

Earthworms Provide Cancer-Fighting Bacteria

Reuters - Innovations Video Online (Dec. 21, 2014) Polish scientists isolate bacteria from earthworm intestines which they say may be used in antibiotics and cancer treatments. Suzannah Butcher reports. Video provided by Reuters
Powered by NewsLook.com
Existing Chemical Compounds Could Revive Failing Antibiotics, Says Danish Scientist

Existing Chemical Compounds Could Revive Failing Antibiotics, Says Danish Scientist

Reuters - Innovations Video Online (Dec. 21, 2014) A team of scientists led by Danish chemist Jorn Christensen says they have isolated two chemical compounds within an existing antipsychotic medication that could be used to help a range of failing antibiotics work against killer bacterial infections, such as Tuberculosis. Jim Drury went to meet him. Video provided by Reuters
Powered by NewsLook.com
Hugging It Out Could Help You Ward Off A Cold

Hugging It Out Could Help You Ward Off A Cold

Newsy (Dec. 21, 2014) Carnegie Mellon researchers found frequent hugs can help people avoid stress-related illnesses. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins