STANFORD, Calif. The onset of narcolepsy appears to follow seasonal patterns of H1N1 and other upper airway infections, according to a new study of patients in China that was led by Stanford University School of Medicine narcolepsy expert Emmanuel Mignot, MD.
The findings, which will be published online Aug. 22 in Annals of Neurology, a journal of the American Neurological Association and Child Neurology Society, show that a peak in narcolepsy cases occurred five to seven months after a peak in flu/cold or H1N1 infections in the country.
"Together with recent findings, these results strongly suggest that winter airway infections such as influenza A (including H1N1), and/or Streptococcus pyogenes are triggers for narcolepsy," Mignot, a professor of psychiatry and behavioral sciences, and his colleagues wrote in the paper.
The study follows recent reports that a particular H1N1 vaccine, not one used in the United States or China, seemed to lead to narcolepsy. This new paper, however, found no correlation between vaccination and narcolepsy among the patients studied in China. "The new finding of an association with infection, and not vaccination, is important as it suggests that limiting vaccination because of a fear of narcolepsy could actually increase overall risk," the authors wrote.
Approximately 3 million people worldwide suffer from narcolepsy, a neurological disease that is characterized by daytime drowsiness, irregular sleep at night and cataplexy a sudden loss of muscle tone and strength. In 2009 Mignot and colleagues confirmed scientists' long-held suspicion that narcolepsy is an autoimmune disease, caused when patients' immune systems kill the neurons that produce the protein hypocretin.
Experts believe that a person has a genetic predisposition to the disease, and some environmental factor kicks his or her immune system into action leading to narcolepsy. As noted in the paper, past studies have sho
|Contact: Michelle Brandt|
Stanford University Medical Center