Both type-1 diabetes and MS are auto-immune diseases, where the body builds up an aberrant immune response against itself, attacking insulin-producing cells in patients with diabetes, and the myelin sheath of the neurons in those suffering from MS.
Dr. Nete M. Nielsen, from the Statens Serum Institut in Copenhagen, and colleagues, evaluated the emergence of MS in 6078 patients with type-1 diabetes with more than a decade of follow-up, and observed that patients with type- 1 diabetes had a more than three-fold increased risk of MS.
Their study has been reported in the Archives of Neurology.
The researchers also studied the presence of type-1 diabetes in 14,771 first-degree relatives of 11,862 MS patients and found that first-degree relatives of MS patients had a 63 percent increased risk of developing type-1 diabetes.
"To our knowledge, the present study is the first truly nationwide cohort study to demonstrate intra -individual and, to a lesser degree, intra -familial co-occurrence of MS and type 1 diabetes," the investigators claim.
"The underlying mechanisms remain unknown, but may involve both genetic and environmental factors." they added.