SATURDAY, Nov. 5 -- Exposure to certain types of air pollution is associated with an increased risk for the painful joint disease known as rheumatoid arthritis, new research suggests.
This link is strongest for sulfur dioxide, one of the six most common air pollutants in the United States, according to the findings from two studies scheduled to be presented Wednesday at the American College of Rheumatology annual meeting, in Chicago.
In the studies, investigators looked at 2,092 rheumatoid arthritis patients and more than 93,000 people without the disease in the United States and Sweden, and used their home addresses to estimate their long-term exposure to several common air pollutants, both gaseous (for example, carbon monoxide, sulfur dioxide and nitrogen dioxide) and particulate (soot or dust).
There was no evidence of increased risk of rheumatoid arthritis associated with particulate air pollution. But increasing exposure to sulfur dioxide and oxides of nitrogen in the 10 and 20 years prior to onset of rheumatoid arthritis was associated with increased risk of the disease among the Swedish participants, the investigators found.
Low-, medium- and high-exposure to sulfur dioxide, nitrogen dioxide or nitrogen oxide were associated with an up to 7%, 11% and 7% increased risk for rheumatoid arthritis, respectively, according to the Swedish study.
These increased risks of rheumatoid arthritis were higher in people with less than a university education than in those with at least a university education. Education levels are a measure of socioeconomic status.
People "with a lower socioeconomic status are more likely to live in houses where more air pollution leaks in from the outside or other factors such as general health status that may make them more susceptible to the effects of air pollution," Dr. Jaime Hart, an instructor in medicine at Brigham and Women's Hospital in Boston, said in an American College of Rheumatology news release.
Hart was lead investigator of the U.S. study and was scheduled to present the U.S. and Swedish findings at the meeting.
The U.S. study found that only exposure to sulfur dioxide was associated with modest increases in rheumatoid arthritis risk. Those with a high exposure to sulfur dioxide had a 5% greater risk of rheumatoid arthritis than those with low exposure.
But Hart noted that the U.S. participants were part of the Nurses' Health Study, which meant they may have had a higher overall socioeconomic status than the Swedish participants.
Study data and conclusions presented at medical meetings should be viewed as preliminary until published in a peer-reviewed journal.
About 1.3 million Americans have rheumatoid arthritis, which typically affects women twice as often as men. Previous research has suggested a connection between environmental factors and rheumatoid arthritis.
-- Robert Preidt
SOURCE: American College of Rheumatology, news release, Nov. 5, 2011
-- A spinal fracture occurs when a small bone in the spine cracks, often a result of soft, brittle bones caused by osteoporosis.
The American Academy of Orthopedic Surgeons lists these common warning signs of a spinal fracture:
-- Exercise can help improve many symptoms of osteoarthritis, a joint disease that causes pain and stiffness.
The Arthritis Foundation mentions these potential benefits of exercise to people with osteoarthritis:
-- Arthritis can affect any joint, but weight-bearing joints such as the knee are particularly vulnerable.
The American Academy of Orthopaedic Surgeons mentions these common symptoms of knee arthritis:
Study Shows TNF Inhibitors Have No Increased Risk of Other Cancers
By Daniel J. DeNoon
WebMD Health News
Reviewed by Laura J. Martin, MD
Sept. 7, 2011 -- A popular class of rheumatoid arthritis drugs may slightly increase skin cancer risk but not the risk of other cancers, a "reassuring" study finds.
Cimzia, Enbrel, Humira, Remicade, and Simponi all inhibit a natural protein called tumor necrosis factor alpha (TNFa). TNFa plays a major role in arthritis. It also plays a major role in protecting the body from infections and cancer.
The clinical trials that led to the drugs' approval showed no sign of increased cancer risk. But cancer takes a long time to develop. Worries remained that as time went on, a cancer risk would appear, says University of Miami rheumatologist Ozlem Pala, MD.
A 2006 report in the Journal of the American Medical Association found evidence of increased cancers and serious infections in patients taking anti-TNF drugs. But later studies failed to confirm the cancer risk.
"We are more or less sure now we won't see a really big increased risk of cancer with these medicines," Pala tells WebMD. "It is definitely better than what we were afraid of. But we still have to be really cautious about the possibility of cancer risk [in patients on TNF inhibitors]."
A recent analysis of clinical trial data found no increased cancer risk for TNF inhibitors -- except for an increased risk of skin cancer. Now a new analysis of patient follow-up data confirms these findings, study leader Xavier Mariette, MD, PhD, of the University of Paris, tells WebMD.
"We had exactly the same results. It means there was no increased risk of cancer in patients treated with TNF inhibitors compared to [other RA drugs]," Mariette tells WebMD. "It is very reassuring. But we did also observe an increased risk of non-melanoma skin cancer."
Mariette and colleagues also found a trend indicating increased risk of melanoma in patients on TNF inhibitors -- but this finding was weak and could have been due to chance.
Mariette notes that anti-TNF drugs weaken part of the the immune system. And such drugs are known to increase the risk of skin cancers, he says, so he is not surprised to find that anti-TNF drugs increase non-melanoma skin cancer risk by 45%.
"This means that doctors should be cautious with these drugs in patients with high lifetime sun exposure," he says. "But patients also should be aware that non-melanoma skin cancers are easily treatable."
Cimzia and Simponi were approved only two years ago. They were not included in the analyses of cancer risk by Mariette and previous researchers.
But Pala says that while the five current anti-TNF drugs are different from one another, any cancer or infection risk is probably common to the entire class of drugs.
The Mariette study appears in the Sept. 8 online issue of the Annals of Rheumatic Diseases.
SOURCES: Mariette, X. Annals of Rheumatic Diseases, published online Sept. 8, 2011.Bongartz, T. Journal of the American Medical Association, May 17, 2006.Askling, J. Pharmacoepidemiology and Drug Safety, February 2011.Xavier Mariette, MD, PhD, Institute for Health and Medical Research (INSERM), University of Paris.Ozlem Pala, MD, assistant professor of rheumatology, University of Miami Miller School of Medicine. ©2011 WebMD, LLC. All Rights Reserved.