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From 1962 to 1984,age-specific mortality for motoneuron disease(MND)in the United States rose in all demographic groups over the age of 40.The increase was seen in both men and women,and both elderly(eg,378%in white women aged 80-84 years).Men were at 50%higher risk than women,and whites had twice the risk of non-whites.These increases may reflect an improvement in case ascertainment,but they also seem to show a true rise in the incidence of MND,particularly among the elderly.Such an increase suggests an environmental aetiology. |
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