Maternal mortality is surely a factor, no?
Antibiotics helped.
Pesticides like DDT that killed disease transmitting lice and mosquitoes helped (although there were later problems with it killing other lifeforms).
Improved surgical techniques helped, along with safer anesthesia.
Improved infrastructure in regards to water treatment and sewage helped.
Improved vaccines helped.
And so on, and so forth. The mistake is in looking for just one thing that changed survival rates.
Medicare started in the mid-sixties. The elderly who once would have just died from trivial things are now getting medical treatment.
Ding ding ding!
The big gains in life expectancy during those decades were not a reflection of living longer once someone made it being an adult but in the huge number of lefe years added by preventing childhood deaths. Look at figures one and two here. (pdf)
I’m going to defend the OP on this. Using those who already made it to 21 as a baseline factors out improvements in eliminating childhood deaths.
Well, to be strictly fair, some childhood diseases might cause lingering effects that could kill you, or render you more vulnerable, after childhood. But yeah, that’ll be a small component, and starting at 21 should mostly rule out the childhood diseases.
No, my bad. Skimmed the op too quickly.
Still young adult death decrease probably led the decline in the early years of the time period and for the same reasons … fewer deaths due to pneumonia, influenza, and unintentional injuries. Secondary to improved nutrition, improved living conditions, and medical care inclusive of the wide spread use (and over-use) of antibiotics. In more recent years better care for heart disease and decreased tobacco use have pushed the deaths at 40 to 60 out to 70 to 80 sometimes. Medicare giving the poor access to basic care also had a major impact.
I’ll see if I can find something on how many died at what age by decade …
Here’s (pdf) 1979 to 1998 and and here is 1940. 1940 162K/1,000,000 in the 25 to 34 range (the highest of any adult decadal cohort). 1998 the same 25 to 34 year old cohort was about 1K/1,000,000 (the lowest of all adult decadal cohorts).
It occurs to me that advances in communications, emergency response, and medevac capabilities over the last fifty years must have also saved an incredible number of lives.
Progress never comes to a halt. Life-saving technologies build on one another all the time, in all fields, so it’s hardly surprising that the trend is consistently upward.
Perhaps, but the average life expectancy is by definition average precisely because it reflects mortality throughout the human lifespan.
The latter is genetically determined and seems to be around 100 years, give or take a few.
Sorry but your post terentii seems a bit confused. Average life expectancy and upper limit lifespan are very different things. Hence the importance of my mistaken read of the op and of my being able find documentation that the big change between the 40s and 1979 (in deaths after age 21) was in fewer deaths among the youngest adults. Since then the drop in rate per unit population has been more evenly distributed with the only cohort increasing being those who die after 85 and the biggest absolute number drops in the 65 to 84 groups.
You may be interested in this read from Science (I hope not behind the paywall). Some excerpts -
Short version - there is no way to know if there is any such 100 year old or any specific genetic limitation and the fact that those who reach 100 are dying less soon than they used to argues strongly against 100 years as such a limit.
Not to mention 675,000 dead as a result of the Spanish Flu epidemic.
Sorry, I thought I made the difference very clear. I remember an interview with Christiaan Barnard many years ago in which he made precisely that distinction.
Life expectancy can be altered by environmental factors and lifestyle. Lifespan cannot be altered except through evolution.
I’m on Olshansky’s side of this bet. The curve so far certainly seems to be asymptotic. Since we’re already regularly seeing people live to 115 the limit must be higher than that, but there’s no reason to push it to 150. Doing so would require some unknown breakthrough - not impossible but not predictable either. And the big issue is whether life from 90 to 150 could ever be meaningfully active, mentally and physically. Adding 50 years to be spent in an institution is pure cruelty.
Exactly the sort of deaths that antibiotics would lessen. All those flu shots every year alone must save thousands of lives.
“Regularly”? Really? :dubious:
A bit more often than in the past, perhaps, but I wouldn’t say it’s “regularly.” People who live as long as 115 years have got to be statistical outliers, gene-wise.
Nonogenarians and centenarians are more a tribute to improved geriatric care, I should think.
Obviously, the oldest people are outliers. What’s interesting is that the standard for the extreme keeps creeping upward. There are five known people alive today who were born in 1898 or 1899. Wikipedia’s list of the 100 known oldest only goes down to 114 years, 29 days. Jeanne Calmentlived to be 122. There are hundreds of thousands of known centenarians worldwide, and the number per million population has increased since the end of WWII far faster than the total population. Only 1 in 1000 centenarians are estimated to live to be 110, though, which is why I call the trend asymptotic.
So really, in a broad sense, we could say that the difference is probably most attributable to applications of the germ theory of disease, which was still being nailed down at about the time the 1896 cohort was born, and practical applications didn’t come along until later (antibiotics, antiseptics, vaccinations, related public health initiatives, and the like), but were either completely or mostly in place for the 1946 cohort.
I would take that side of the bet too but the fact is that we do not yet know and any statement as to what the biologic limit is is pure speculation.
From a practical POV it is likely to be like other aspects of biologic function. Take the fastest mile run. In 1865 it was 4.36.5. Go by roughly 15 year steps and the change was faster by almost 9 seconds the first 15 year step, 7 seconds the next, 12 the next, 8 the next (in 1985), and then only 3 seconds gained by 15 years later and none since (been about another 15 years). No doubt the current record will broken but there is not going to be gains of 7 to 12 seconds every 15 years from here.
Here’s some evidence that it will behave in that “probabilistic barrier” fashion, looking at two groups - supercenterians and Olympians.
Of course these sorts of analysis do not allow for changes in the understanding of the aging process and possible interventions. Cancer and aging both seem to largely functions of accumulated errors and changes over the history of cell divisions (hence tissues that have more divisions tend to be the tissues in which cancers occur).
I don’t think the comparison between highest age and fastest mile is accurate because for running a mile there is a long list of things you cannot do to enhance your performance.
If someone took steroids, growth hormone, cocaine, epo and then stuck giant springs in their shoes they could probably beat the current world record. But that would not be considered valid.
The same applies with human longevity. In 2010 there were 53,364 centenarians in the US. Only 0.6% of them were 110 or older, and about 84% are women.
Seeing how there were almost 3 million births (2.77 million) a year around 1910, that means only a tiny fraction of those people lived to 100. Also you’d have to look at births from 1895-1910 to get a more accurate picture. Either way, it is less than 1%.
There were about 30k people aged 100-101 in 2010, the only survivors of about 5.5 million people born in 1909 and 1910.
So less than 1% of people live to 100. Of those survivors, less than 1% live to 110. Only 1 person has been verified to survive to 120. Maybe you can’t say there is a definite number, but 135 as an example is a reasonable upper limit on human longevity barring massive medical advances based on human track records. Then again, good record keeping didn’t exist pre 20th century either so finding verified births before then was much harder.
Will people live longer than that someday? Yes, but only because they are so inundated with medical technology that they aren’t technically ‘human’ anymore. Someone born today will probably live to 150. But when they do they will have (among other things).
[ul]
[li]Stem cells to replace cells, tissues and organs lost with age[/li][li]A wide cocktail of medical interventions to reactivate all the self repair mechanisms that stop working with age (basically what compounds like resveratrol claim to do, but far more effective)[/li][li]Mechanical muscles and organs[/li][li]Gene therapy[/li][li]Manmade red blood cells[/li][li]Augmented immune system[/li][/ul]
You can’t really say because that person lives to 150 that that means 150 is the human upper limit. No unenhanced human is going to live that long. You might as well extrapolate out to 500 years from now when aging is totally cured and people can live to be 5000+ years old in the bodies of 25 year olds.
Beat it by 7 seconds or more? Doubtful. Even with enhancers we come near a probablistic limit, not a wall, but smaller gains even with enhancers.
But yes, major breakthroughs in the understanding of the basics of the aging process could potentially shift the location of the limit. Barring that I would bet against the 150 side. I won’t be alive to find out though.