While analysing trends in occupational deaths in England and Wales, researchers noticed an unexpected elevated proportion of mortality rates as a result of multiple sclerosis (MS) among men in the armed forces.
The study, “Mortality from multiple sclerosis in British military personnel”, published by Oxford Academic explored possible explanations for the observed excess.
Researchers analysed data on underlying cause of death and last full-time occupation for 3,688,916 deaths among men, aged 20-74 years, in England and Wales during 1979-2010, calculating proportional mortality ratios standardised for age. They compared proportional mortality rates for MS in the armed forces with those for each main social class, and in selected other occupations. They also compared proportional mortality rates for MS with those for motor neurone disease (MND).
Men from the armed forces were found to have experienced elevated proportional mortality from MS in each of three successive decades, with proportional mortality rates between 220 (1971-1990) and 259 (1991-2000) at ages 20–74 years.
When the mortality rate of the armed forces was compared to other occupations, such as police, fire service and sportsman there was a 30.8%, 37% and 76.5% decrease in mortality rate respectively.
Commenting on the findings, the authors said: “These findings suggest that the high proportional mortality from MS in British military personnel is unlikely to have occurred by chance, or as an artefact of the method of investigation.
“Moreover, our findings suggest that it cannot be explained entirely by selective exclusion from other employment when leaving the military, by low mortality in servicemen from the most common causes of death or by non-occupational factors related to social class. The possibility of an unidentified occupational hazard remains.
“However, the only military cohort study with published results on MS does not support an increased risk. It would be useful to analyse data on MS from other established military cohorts, to check for evidence of a hazard,” they added.