Longitudinal Gompertzian analysis of Parkinson's disease mortality in the U.S., 1955-1986: the dramatic increase in overall mortality since 1980 is the natural consequence of deterministic mortality dynamics.

Age-adjusted mortality rates for Parkinson's disease (PD) for men and women in the United States, from 1955 to 1986, were calculated and subjected to longitudinal Gompertzian analysis. Annual age-adjusted PD mortality rate distributions were determined by a common intersect point and a variable environmental factor. For men, the death rate at age 73.75 years was 19.15/100,000; for women, the death rate at age 78.99 years was 28.64/100,000 for each year from 1955 to 1986. The environmental factor declined (improved) 360.7-fold for men and 319.6-fold for women in 1986 compared to 1955. Despite this dramatic environmental improvement favoring survival in PD, there has been a 57.6% increase since 1980 in the annual crude PD mortality rate for men compared to the stable annual crude mortality rate from 1955 to 1979. A corresponding 37.9% increase in the annual crude PD mortality rate for women has also occurred since 1980. The increase in overall mortality is due entirely to rapidly increasing age-adjusted mortality rates at ages greater than the intersect points for men and women. The results suggest that overall mortality due to common 'degenerative' diseases may increase dramatically as has occurred in PD.