http://goo.gl/YAoA13
The latest environmental influence, observed by Mauricio Farez, a neuroscientist at the Raúl Carrea Institute for Neurological Research, and colleagues could involve peak melatonin levels in the body, which occur during the darker months. The researchers assessed a group of 139 multiple sclerosis patients in Buenos Aires and found a 32 percent reduction in the number of relapses in the fall and winter, when people living in the Southern Hemisphere produce more of the hormone, compared with summer and spring. The results are published on the September 10 Cell.
Past research has shown that melatonin can have a protective effect against MS and that shift work, which disturbs melatonin production, can increase the risk of developing the disease. According to the authors, this research is one of the first to bring together epidemiological evidence with results from both human cells and animal models.