Lest there be any doubt that medicine is an amazing thing, an updated systematic review of when and why people die shows that in just the past two decades the global life expectancy has ticked upwards by around 6 years, on average.
Women eked a little more lifetime than men did, says Agence France Presse, but taken as a whole the global life expectancy jumped from 65.3 years to 71.5 years since 1990—6.2 years of extra life picked up in just 23 years of progress.
The improvements in prolonging life were spread around the globe, says the report: in high-income countries, we've gotten better at fighting cardiovascular diseases and cancer. In lower-income countries, we've gotten way better at keeping babies alive. Sadly, though, not every region saw similar improvements: in sub-Saharan Africa, life expectancy actually went down because of HIV/AIDS.
The results show that, in general, we're getting way better at fighting the full range of communicable diseases. But people need to die of something, and an aging population means that non-communicable diseases are taking up the reaper's scythe. According to an accompanying press release, the top causes of death globally are now ischemic heart disease, stroke, chronic obstructive pulmonary disease, pneumonia and Alzheimer's disease. The big winner here is that diarrheal diseases, one of the top five killers in 1990 and one of the leading causes of death in children, has been pushed off the list.
This bump is part of amuch longer term trend. As Nature wrote a few years back, the world saw big gains in life expectancy in the 19th and 20th centuries because of improvements in sanitation, housing, education and the introduction of vaccines. With these challenges largely met in the western world, gains in life expectancy in the U.S. and other first world countries now mainly come from extending people's golden years.
In other parts of the world, however, these basic health challenges have yet to be met. As better basic healthcare and sanitation spread, some countries are seeing huge gains in life expectancy. According to Agence France Presse, “some low-income countries such as Nepal, Rwanda, Ethiopia, Niger, the Maldives, Timor-Leste and Iran had seen exceptional gains over the past 23 years with life expectancy in those countries rising by more than 12 years for both sexes.”