Stage 4 of the Epidemiological Transition is Degenerative Diseases. Which is diseases like cancer, and Alzheimer. You often see these in older people, this is connected with Stage 4 of the Demographic Transition, because in the demographic transition there is a Large elderly population, and people aren't having babies to replace them. People are more urbanized, and couples aren't having children because of their busy jobs. Therefore, your population will have low to no growth, elderly people would be the largest age group, and the diseases would be high in the elderly age group.