The size of the subpopulation susceptible to malignant neoplasm of the brain.

A decline of mortality dependence on age from the exponential relation is observed for some diseases. This decline could be explained by the existence of an inherently susceptible population subset which is depleted faster than the general population. A model is presented which describes this situation using malignant neoplasm of the brain. The model assumes that only those who are members of the subset can die of malignant neoplasm of the brain. This model was used to fit the actual mortality curve of malignant neoplasm of the brain for women and men in the USA in 1979. The size of this subset equalled one of two parameters used to fit the actual data. The decline of mortality dependence upon age can be explained by this model. The size of the subpopulation is 0.390% for men and 0.417% for women. The theoretical curves resulting from that model capture the actual mortality due to malignant neoplasm of the brain.