This study characterizes a new nationwide incident cohort of MS from the US military-veteran population. This cohort provides an update to the only other US nationwide incidence study of MS performed during the 1970s. Medical records and data from the Department of Defense and Department of Veterans Affairs for cases of MS who served in the military between 1990, the start of the Gulf War era, and 2007 and who were service-connected for this disorder by the Department of Veterans Affairs from 1990 on, were reviewed. A total of 2691 MSers were confirmed as having MS: 2288 definite, 190 possible, 207 clinically isolated syndrome and six neuromyelitis optica. Overall racial categories were White, Black and other, which included all Hispanics. There were 1278 White males and 556 females; 360 Black males and 296 females; and 200 others, 153 (77%) of whom were Hispanic. Mean age at onset of 30.7 years did not differ significantly by race or sex. Age at onset was 17–50 years in 99%, the same age range as 99% of the military. Average annual age specific (age 17–50 years) incidence rates per 100 000 for the entire series were 9.6 with 95% confidence interval of 9.3–10.0. Rates for Blacks were highest at 12.1 with confidence interval 11.2–13.1, Whites were 9.3 (interval 8.9–9.8) and others 6.9 (interval 6.0–7.9). For 83 Hispanics defined for 2000–07, the rate was 8.2 (interval 6.5–10.1). Much smaller numbers gave rates of 3.3 for Asian/Pacific Islanders and 3.1 for native Americans. Rates by sex for Whites were 7.3 and 25.8 male and female, respectively, for Blacks 8.4 and 26.3, and for Hispanics 6.6 and 17.0. Rates by service were high for Air Force (10.9) and Army (10.6), medium for Navy (9.1) and Coast Guard (7.9), and low for Marines (5.3). Relative risk of MS was 3.39 female:male and 1.27 Black:White. These new findings indicate that females of all races now have incidence rates for MS some three times those of their male counterparts and that among these groups, Blacks have the highest and others (probably including Hispanics) the lowest incidence rates regardless of sex or service. The low rate for Marines is unexplained. This Gulf War era multiple sclerosis cohort provides a unique resource for further study.
“We have been saying that MS has become a predominantly female disease, which is supported by this study of American miltary personnel. The sex ratio of female to male is over 3:1. The astonishing thing is that the ratio of black to white MSers has reached parity and in fact is exceeding the amount of MS in white military personel.This has changed from the Second World war era when the ratio of white males to black males was 2 to 1, now it is one to one in the Gulf War Era (1990 to 2007).”
“The table from the paper shows the ratio of MS relative to white males in US forces over history.”
“The rate of smoking has probably dropped in this cohort of people over this period, but the data further indicate the importance of environmental factors in determining whether MS occurs. It suggests that by modifying the environment we can prevent MS from occurring in some people. MS clearly does not discriminate; although saying that it clearly favours woman.”