Parkinsonism mortality in the US, 1. Time and space distribution

ABSTRACT We studied the time‐space variations of mortality for parkinsonism in the US during the periods 1962‐1985 and 1971‐1978 from statistics on primary cause‐of‐death and multiple causes‐of‐death, respectively. Linear regression analysis and a test for significance of spatial clustering were used. For parkinsonism as a primary cause‐of‐death, up to the late 1970's there was a decrease in mortality for the age groups below 75 and stable rates for the age group 75 years and over. A moderate decrease among those below 75 years, and a sharp increase in mortality among those over 74, were observed for the period since the late 1970s. The variation of the age‐specific mortality during the period 1962‐1985 ranged from 100% in the age group 35‐44 years to + 98% in those aged over 84 years. Within the same age group, the variations across time of mortality due to, and related to parkinsonism, for the period 1971‐1978, were similar. In the spatial analysis, an association between mortality related to parkinsonism and geographical latitude was found. We conclude that: 1) parkinsonism at death is widely distributed; 2) the changes across time can not be explained by a reduction in general mortality; 3) improvements in diagnostic ascertainment and reporting among the elderly may have particularly occurred during the last decade; and 4) the disorder has been progressively confined to the elderly by diminishing in the younger birth cohorts. 1991 Blackwell Munksgaard