Secular trends in mortality rates from motor neuron disease in Kentucky 1964-1984

All death certificates with amyotrophic lateral sclerosis (ALS) or motor neuron disease (MND) as the primary or underlying cause occurring among Kentucky residents between 1964 and 1984 were manually reviewed. Geographic variability within Kentucky was evident for three intervals, 1964-1967, 1968-1978, and 1979-1984, with a more marked pattern among females than among males. There was a shifting age pattern of MND mortality with a higher proportion of cases in older ages for the most recent time period. Again, this pattern was more marked among females. Furthermore, there was a slight increase in total average annual age adjusted ALS/MND mortality rates over the three intervals. The increase is slight, but with the previous stability of reported rates and the shifting geographic and age patterns, there is evidence to support the need for incidence studies targeted at specific and environmental exposures.