An extract from a paper by the National Bureau of Economic Research (NBER):
Robert Lucas once famously said regarding the determinants of economic growth, “once one starts to think about them, it is hard to think of anything else.” The same could be said for the determinants of mortality, since the length of life is as critical a measure of our wellbeing as is our income.
In “Determinants of Mortality” (NBER Working Paper 11963), David Cutler, Angus Deaton, and Adriana Lleras-Muney explore many aspects of this important topic, including the decline in mortality rates over time, differences in mortality across countries, and differences in mortality across groups within countries.
For most of human history, life expectancy has been short – perhaps 25 years for our hunter-gatherer ancestors and only 37 years for residents of England in 1700. Dramatic changes began in the 18th century, with life expectancy in England rising to 41 years by 1820, 50 years by the early 20th century, and 77 years today. The decline in mortality rates was particularly sharp among children. This can be explained by the near elimination of deaths from infectious diseases, formerly the most common cause of death, since the young are most susceptible to infection.
Read more of the outline at: http://www.nber.org/aginghealth/spring06/w11963.html
Reference of original source: http://www.nber.org/papers/w11963