what is epidemiological transition
The epidemiologic transition describes changing patterns of population age distributions, mortality, fertility, life expectancy, and causes of death.
In demography and medical geography, epidemiological transition is a phase of development witnessed by a sudden and stark increase in population growth rates brought by medical innovation in disease or sickness therapy and treatment, followed by a re-leveling of population growth from subsequent declines in fertility rates. “Epidemiological transition” accounts for the replacement of infectious diseases by chronic diseases over time due to expanded public health and sanitation. This theory was originally posited by Abdel Omran in 1971.
There are two major components of the transition: (1) changes in population growth trajectories and composition, especially in the age distribution from younger to older, and (2) changes in patterns of mortality, including increasing life expectancy and reordering of the relative importance of different causes of death.
Initially, there were high prevalence of infectious disease but with invention of vaccines and new medicines followed by high standard of living and better hygiene, the people suffering and dying from infectious diseases has been decreased, but with time and evolution of new medicines, green revolution etc. the death rate because of famine and infections has been decreased but a new problem has arisen i.e. of chronic diseases which includes diabetes, obesity, BP etc.