Rising mortality from motor neurone disease: an explanation

Area of Science:

• Epidemiology
• Neurology
• Public Health

Background:

• There is ongoing debate regarding the rise in motor neurone disease (MND) mortality.
• Increased life expectancy, resulting from decreased general mortality, is closely associated with rising MND mortality rates.

Purpose of the Study:

• To investigate the relationship between increased life expectancy and motor neurone disease (MND) mortality.
• To identify and estimate the size of sub-populations susceptible to MND.
• To project future trends in MND mortality.

Main Methods:

• Statistical modeling was employed to analyze mortality data from England and Wales and the United States.
• Sub-populations susceptible to MND were identified and their size estimated using 1989 mortality data.
• Trends in MND mortality within these sub-populations were examined over a 30-year period.

Main Results:

• A sub-population of approximately 160,000 individuals in England and Wales was identified as susceptible to MND.
• The proportion of this susceptible sub-population dying from MND has increased over the past 30 years.
• MND deaths within this group are projected to rise by an additional 20% between 1991 and 2021 due to ongoing changes in life expectancy.

Conclusions:

• The increasing visibility of MND in mortality statistics is primarily due to decreased general mortality, not a substantial change in the at-risk population.
• Susceptibility to MND appears to be acquired early in life.
• Changes in environmental factors or artifacts are unlikely to solely explain the observed rise in MND mortality.