Longitudinal Gompertzian analysis of stroke mortality in the U.S., 1951–1986: Declining stroke mortality is the natural consequence of competitive deterministic mortality dynamics

Abstract

Age-adjusted mortality rates for stroke in the United States from 1951 to 1986 were subjected to longitudinal Gompertzian analysis. Age-adjusted stroke mortality rate distributions were determined by a variable environmental factor and a constant Gompertz slope. Compared to 1951 values, the environmental factor in 1986 had declined (improved) 49.8% for men and 59.1% for women. This was associated with a 51.9% and 31.4% decrease in the annual crude mortality rate from stroke for men and women respectively. However, the Gompertz slope remained remarkably constant from 1951 to 1986; 0.050152 for men and 0.048341 for women. The constant Gompertz slope for age-adjusted mortality rate distributions for stroke is in sharp contrast to the increasing Gompertz slope which occurs with an improving environment in ‘degenerative’ diseases and aging in general. These findings suggest that the recent dramatic decline in overall stroke mortality is the natural consequence of competitive deterministic mortality dynamics. As the overall environment becomes more conducive to human survival, Gompertzian diseases with converging mortality rate distributions must increase as causes of human mortality at the expense of diseases with constant Gompertz slopes.