The Gulf War era multiple sclerosis cohort: 3. Early clinical features.

Objectives: To present clinical features at diagnosis for a large nationwide incident cohort of multiple sclerosis (MS) among those serving in the US military during the Gulf War era (GWE).

Materials & Methods: Medical records and databases from the Department of Veterans Affairs (VA) for cases of MS with onset in or after 1990, active duty between 1990 and 2007 and service connection by the VA, were reviewed for diagnosis and demographic variables. Neurological involvement was summarized by the Kurtzke Disability Status Scale (DSS) and the Multiple Sclerosis Severity Score (MSSS).

Results: Among 1919 cases of clinically definite MS, 94% had a relapsing-remitting course and 6% were primary progressive at diagnosis. More males of all races and blacks of both sexes were progressive. At diagnosis, functional system involvement was pyramidal 69%, cerebellar 58%, sensory 55%, brainstem 45%, bowel/bladder 23%, cerebral 23%, visual 18%, and other 5%. Mean DSS scores were: white males, females 2.9, 2.7; black males, females 3.3, 2.8; and other-race males, females 3.2, 2.6. Mean and median MSSS were marginally greater in black males and other males compared to the other sex-race groups.

Conclusions: In this incident cohort, males and blacks had significantly higher proportions of primary progressive MS. DSS at diagnosis was significantly more severe in blacks and significantly less so in whites and in women vs men, but MSSS was only marginally greater in black males and other-race males. This morbidity assessment early in the course of MS provides population-based data for diagnosis, management, and prognosis.