Optic neuritis, diabetes mellitus and multiple sclerosis: a three-way association.

Patients with multiple sclerosis (MS) and a history of optic neuritis were compared with MS patients who had no such history for other illnesses among themselves and their family members. Significantly more of the patients with a history of optic neuritis than of those without (70% v. 41%) were diabetic or reported that at least one first- or second-degree relative had diabetes mellitus. No differences were found with regard to any other illnesses.