Seems to be one of the most common mistakes.....mixing up cause and correlation in medicine.
http://online.wsj.com/article/SB1000142 ... 37192.html
By THOMAS M. BURTON
A new multiple-sclerosis study debunks a theory about a potential cause for the autoimmune disease that had been embraced by patients around the world, who had turned to risky surgeries to unblock neck veins when drug treatments didn't work for them.
The first large look at whether vein blockages in necks cause MS concludes that such blockages don't have a "primary causative role" and might instead be a result of the disease. The peer-reviewed study by researchers at the State University of New York at Buffalo is to be presented in Hawaii on Friday.
The theory that blockages in the jugular or other veins that drain the brain might contribute to MS has spread globally over the Internet among patients badly debilitated by MS who weren't necessarily helped by drugs. Many of these patients have undergone expensive and risky surgeries to have veins unclogged.
The vein-blockage theory originated with Italian vascular surgeon Paolo Zamboni. In 2009, he reported finding "conclusive" evidence of vein blockages in 100% of 109 MS patients and zero in 177 healthy patients. He dubbed the blockages "chronic cerebrospinal venous insufficiency," or CCSVI. Dr. Zamboni couldn't be reached for comment.
The new study found a relationship between MS and blocked veins, but concluded that the results "suggest that CCSVI may be a consequence rather than a cause of MS."
MS expert Lawrence Steinman, a neurologist at Stanford University, said, "Certainly the [vein blockage] hypothesis carries less and less evidence the more that it's studied. He cautioned that "people running around the world to get this procedure done ought to look at the evidence and save themselves the money."
Dr. Steinman, an inventor of the MS drug Tysabri, said he has no financial connections to the vein-unclogging procedures or to Tysabri. He was among those critical of a Stanford colleague who in 2009 implanted stents and performed other procedures on patients to unclog veins before the university shut down the program.
Timothy Coetzee, chief research officer for the National Multiple Sclerosis Society, called the Buffalo study "an important addition to our understanding of MS." while noting that other research is under way, including some funded by the society.
The 500-person Buffalo study included 289 MS patients, 21 patients who had experienced only one MS attack, 26 patients with other neurological diseases and more than 160 healthy "control" patients.
The study found that about 44% of the MS patients tested had no blocked veins, while slightly more than a quarter of the healthy subjects did have blocked veins. Some 42.3% of patients with other neurological conditions had blockages, as did 38.1% of patients who had experienced one MS attack.The researchers noted that the blockages were more prevalent in longer-term forms of MS.
The research is to be presented at the American Academy of Neurology meeting in Honolulu.
Robert Zivadinov, the Buffalo neurologist who led the study, theorized that vein blockage might result because people with relatively advanced MS are able to move less and have less blood flow to their brains
