7 ms·

One thing which I always thought of, but which the article doesn't mention, is age. Especially older people seem more prone to cancer, so in my mind a lower lif

One thing which I always thought of, but which the article doesn't mention, is age. Especially older people seem more prone to cancer, so in my mind a lower life expectancy will naturally lead to a lower cancer rate, as people die before cancer "is able to get them". Or am I missing something?

eliben 5y ago
Yes, age and life expectancy is a huge part of it. In the book "Rebel Cell: Cancer, Evolution, and the New Science of Life's Oldest Betrayal", Kat Arney touches upon this exact question and reaches the conclusion that cancer was as prevalent in ancient times as it is now (perhaps accounting for surges like smoking-related cancers), and also mentions age as a big factor in the archaeological discrepancy.
GuB-42 5y ago
Yes, I tend to think of an increase of death by heart disease, cancer and neurodegenerescence to be good news overall. These diseases are essentially dying of old age. Better treatment for heart disease will mechanically increase cancer deaths and/or Alzheimer.
- kmonsen 5y ago
  Yeah, you have to die of something and as you get old one of those will hit quite likely.
- Nasrudith 5y ago
  Reminds me of the actuarial sims which excluded all deaths from disease, old age, and traffic accidents. Stairs were one of the top killers but population tapered off even as "cannot die of disease or old age" immortals although some outliers could make it a bit past a millennia.
hanniabu 5y ago
This is a common misconception. Life expectancy hasn't changed much. It's children dying that bright down the average in earlier years. If you lived to your 20s your life expectancy was pretty much the same as it is now.
- linspace 5y ago
  I have heard this multiple times and I would love some citations because although most of the reduction in life expectancy may come from death at child birth, for obvious mathematical reasons, I cannot believe wars, famine and disease don't account for anything
  - watwut 5y ago
    And lack of antibiotics.
  - fpoling 5y ago
    [1] shows pretty convincingly that probability of a dearth due to violence or war has not changed during the last 2000 years. What we perceive as peace is a consequence of extremely violent WWII and to lesser extent WWI that killed vastly more people even after accounting for population increase than wars in the 19th century. [1] - https://www.fooledbyrandomness.com/violence.pdf https://www.fooledbyrandomness.com/violence.pdf
    - watwut 5y ago
      WWII was 80 years ago. So yes, when when we compare current mortality due to violenve with past, we don't count WWII as "current".
- watwut 5y ago
  This is not true. Live expectancy for adults did changed a lot too, just not as much as when you count also kids. > If a medieval person was able to survive childhood, then he had about a 50% chance of living up to 50–55 years. This is from wiki. Our life expectancy is much higher. In fact, contemporary medicine is saving a lot of adults.
- cm2012 5y ago
  No
- jeffbee 5y ago
  According the the US Social Security Administration actuarial tables, the life expectancy of male Americans aged 65 years has gone from 12 to 21 years in the last century. This has massive demographic implications.
strken 5y ago
Perhaps they control for age? A lot of the lower life expectancy was sky-high infant mortality, and if you made it to 10 in 1850 (hardly preindustrial, but preindustrial stats are harder to find) you could expect to live to 60 or so. Presumably you'd compare the cancer rates of your study's skeletons with the cancer rates of today's 60 year olds.
- nemo44x 5y ago
  It’s amazing how precarious being born is. I think I read that about 200 years ago around 40% of people didn’t make it past 5 years old or something like that. Antibiotics have helped a lot in modern times, especially for mothers giving birth.
  - retrac 5y ago
    The improvement in child survival is attributed to many things, but it may be a mix of vaccinations, less indoor air pollution, much better hygiene, better nutrition, and perhaps just better parenting. (People have had some very peculiar ideas on how to care for and raise children; I wouldn't be surprised if in hindsight our distant descendants consider us woefully inadequate in that regard too.) Most of the progress, in absolute terms, with reducing maternal mortality and the infant/toddler death rate in the industrialized countries was actually made before antibiotics were developed, in the late 19th / early 20th centuries. In England in 1851 about 26% of children died before the age of 5, falling to 23% in 1891, 19% in 1911, 11% in 1921, 9% in 1931, and 7% in 1941 (and then we're in the antibiotics era).
  - inglor_cz 5y ago
    From a pair that has been undergoing IVF treatment since November 2019: it is very precarious. There are a lot of opportunities to die before someone draws their first breath.
  - devoutsalsa 5y ago
    Infant mortality was 165 deaths per 1000 births in the year 1900, according to this... https://www.pbs.org/fmc/timeline/dmortality.htm https://www.pbs.org/fmc/timeline/dmortality.htm ...I also like the link to play the video via Real player in the upper left corner :)
7952 5y ago
I think evolution plays a part in why older people are more prone. A debilitating illness in your teens is likely to stop you reproducing and is more likely to vanish. But a genetic trait for cancer later in life can get past on.
- adolph 5y ago
  There must be some evolutionary fitting function that mutations serve that have prevented them from being selected out.
  - HarryHirsch 5y ago
    Amongst the ""hallmarks of cancer" (there's a pair of papers with that title) is tissue invasion, angiogenesis and immunosuppression - and there are genes for that because the placenta needs those so the fetus can survive and reach term. What I'd really like to know is incidence of cancer in marsupials, birds and fishes, one would predict it to be markedly lower.
  - yuliyp 5y ago
    The rate of mutation is significantly lower in humans than in say viruses. Being able to adapt eventually to changing circumstances is valuable.
  - pfdietz 5y ago
    And in very large animals there are adaptations that keep cancer in check, even though they have many more cells. IIRC, elephants have many copies of genes that induce suicide in aberrant cells.
  - mcguire 5y ago
    Not entirely on point here, but you should look at that the other way around: mutations are retained unless they cause adverse consequences that result in them being selected out.
- siggen 5y ago
  Medawar effect
fpoling 5y ago
Also, even if the low average life expectancy was due to excessive mortality among children with chances to live up to 70 once one reached 40 not much different than today, it still does not imply that cancer rates were lower. It could be very well that it is those people who would die as newborn or children without modern medicine and access to clean water have bigger chances of getting cancer with age.
rtkwe 5y ago
Life expectancy is a tricky number to compare across long spans of time because it's heavily influenced by people dying young which was much more common in the past than it is now, people did die earlier but it's not as bad as a say 40 year life expectancy would make it seem because that number is dragged down by lots of early childhood deaths.
- ineedasername 5y ago
  Yes, in 1800, even in more developed countries at the time, about 30% of kids died by age 5. And being pregnant was frequently fatal as well, with nearly 1 in 10 pregnancies killing the mom.
dheera 5y ago
Not only that, but I imagine in pre-industrial times, those who got currently-curable forms of cancer didn't get cured during those times, and Darwinian forces stopped them from reproducing. There isn't a necessarily good or bad here but those Darwinian forces did eliminate a lot of genetic defects from the population before modern medicine. In the future though we might be able to yet again eliminate defects not by natural selection but by gene editing while still allowing those individuals to carry on a normal life.
tejtm 5y ago
Not a biologist, but been around them long enough. I been cultivating a theory that mammals strategy is more or less "go fast; break things". That is, asteroid or not, we were on track to out evolve everything that came before by extending and exploiting explosive cell growth. No animal converts matter & energy to body-mass faster than young mammals, the cold blooded do not stand a chance. The competition would get larger eventually only if some adolescent mammal did not eat them first as peers. consider how you would bet on a 1 year old raccoon vs a 1 year old alligator then again with a 5 year old raccoon vs a 5 year old alligator The mammal strategy traded the long game for the quick win. We have all sorts of (genetic) machinery who's function is to grow fast but then STOP as we can't support gigantic sizes. (Maybe in part because of the quick and dirty foundations but thermodynamics have scaling issues too) So we need to shut of all those machines before we get too big. And so here we happily sit in our bodies, our mammal factory and everything is great; just don't push that big red button over there, or pull that lever or that one or that one or ... eventually if you live long enough some of those buttons will be pushed and the mammal machinery will do what it evolved to do. grow fast and break things. A final observation on humans in particular, recently bipedal, have not gotten all the bugs worked out on that. Deployed a monkey patch for dimorphic gender singling requires cron job flipping on a subset of growth machinery some years after the main global shutdown but only flip them on for a season or so; still seeing evidence of switch bounce issues, see ticket BCRA1.
- Kejiti 5y ago
  We humans are very unique though on how much care and dependency babes need. From an evolutionary perspective natur might have just stoped after we gave birth but for humans you need to be still very healthy for much longer. We have a second evolution which we as a species gained due to our more generic and bigger brain and therefore being able to retain and learn more even through generations. Whenever nature stoped we continued (glasses, cancer treatment etc.) I personally would not subscribe to your idea that cancer is our basis and we just let loose. Cancer is just one sickness of a highly complex system. And after all why would longevity even be a goal for evolution? It's a wishful human idea of lifing forever. I myself I'm looking forward to NOT life forever and still today the thought of not being able to end my life for good is my worst nightmare next to loosing my mind.
nradov 5y ago
Yes if you live long enough eventually some kind of cancer will kill you. This is inevitable due to accumulating cellular damage. Someday it might be possible to repair that damage but it's not clear how.
dsjoerg 5y ago
Your objection is correct, and none of the responses you've received so far seem to have understood your point. I went ahead and read the actual published paper (https://acsjournals.onlinelibrary.wiley.com/doi/epdf/10.1002/cncr.33615 https://acsjournals.onlinelibrary.wiley.com/doi/epdf/10.1002...) and it is just as statistically naive as the NatGeo article made it sound. Let's cartoonishly oversimplify cancer so that we can see how life expectancy would affect observed statistics. Let's say cancer occurrence is 0% for people up to age 40, and then starting on the 40th birthday, cancer occurrence is 10% per year. Everyone who gets cancer dies immediately. Then, imagine that life expectancy in 1500 was 25 years old, standard deviation 10 years (yeah lognormal blah blah just go with it). So, most people don't live to 40, but the ones who do sometimes get cancer. But then, after 1500, life expectancy mean increases by 0.1 years per year. By the year 2000, life expectancy is 75 years old! Much more cancer is going to happen! Many more of the deaths will be from cancer! Cancer itself didn't change. So, these researchers see a lower cancer rate in the bones they're looking at, but they need to do some MATH on the ages these bones and of modern humans to know how to compare cancer rates then to cancer rates now.
- underwater 5y ago
  Life expectancy in the 1500s was much higher if you discard infant mortality. Like 55 years, not 25.
  - zdragnar 5y ago
    Cancer rate after 40 is also not 10% per year. It is a reasonable simplification to demonstrate the point.
    - underwater 5y ago
      If you just make up numbers to create a hypothetical model to explain an observation that's fine. But then it's just a theory. Sebb suggested that lower life expectancy leads to less cancer. Dsjoerg defined a hypothetical model that would lead to that happening, and then said that proves Sebb was correct. That's just circular reasoning. And when the hypothetical doesn't match observed reality it's a sign it might be broken.
Spooky23 5y ago
There were plenty of old people. Life expectancy was skewed by childhood death and urban poor and wasn’t as grim as we think. (Most people lived outside of urban areas) One big thing to consider is how would an 18th century person know they had leukemia? Cancers that don’t have a physical manifestation were probably classified as some other mysterious malady.
m463 5y ago
I remember reading about a drug study where people were given a drug for <something> (I don't recall) and people started dying of heart attacks. Turns out it was curing the <something>, but the next thing the population would statistically die of was: heart attacks.

eliben 5y ago

Yes, age and life expectancy is a huge part of it. In the book "Rebel Cell: Cancer, Evolution, and the New Science of Life's Oldest Betrayal", Kat Arney touches upon this exact question and reaches the conclusion that cancer was as prevalent in ancient times as it is now (perhaps accounting for surges like smoking-related cancers), and also mentions age as a big factor in the archaeological discrepancy.

GuB-42 5y ago

Yes, I tend to think of an increase of death by heart disease, cancer and neurodegenerescence to be good news overall. These diseases are essentially dying of old age. Better treatment for heart disease will mechanically increase cancer deaths and/or Alzheimer.

kmonsen 5y ago
Yeah, you have to die of something and as you get old one of those will hit quite likely.
Nasrudith 5y ago
Reminds me of the actuarial sims which excluded all deaths from disease, old age, and traffic accidents. Stairs were one of the top killers but population tapered off even as "cannot die of disease or old age" immortals although some outliers could make it a bit past a millennia.

hanniabu 5y ago

This is a common misconception. Life expectancy hasn't changed much. It's children dying that bright down the average in earlier years. If you lived to your 20s your life expectancy was pretty much the same as it is now.

linspace 5y ago
I have heard this multiple times and I would love some citations because although most of the reduction in life expectancy may come from death at child birth, for obvious mathematical reasons, I cannot believe wars, famine and disease don't account for anything
- watwut 5y ago
  And lack of antibiotics.
- fpoling 5y ago
  [1] shows pretty convincingly that probability of a dearth due to violence or war has not changed during the last 2000 years. What we perceive as peace is a consequence of extremely violent WWII and to lesser extent WWI that killed vastly more people even after accounting for population increase than wars in the 19th century. [1] - https://www.fooledbyrandomness.com/violence.pdf https://www.fooledbyrandomness.com/violence.pdf
  - watwut 5y ago
    WWII was 80 years ago. So yes, when when we compare current mortality due to violenve with past, we don't count WWII as "current".
watwut 5y ago
This is not true. Live expectancy for adults did changed a lot too, just not as much as when you count also kids. > If a medieval person was able to survive childhood, then he had about a 50% chance of living up to 50–55 years. This is from wiki. Our life expectancy is much higher. In fact, contemporary medicine is saving a lot of adults.
cm2012 5y ago
No
jeffbee 5y ago
According the the US Social Security Administration actuarial tables, the life expectancy of male Americans aged 65 years has gone from 12 to 21 years in the last century. This has massive demographic implications.

strken 5y ago

Perhaps they control for age? A lot of the lower life expectancy was sky-high infant mortality, and if you made it to 10 in 1850 (hardly preindustrial, but preindustrial stats are harder to find) you could expect to live to 60 or so. Presumably you'd compare the cancer rates of your study's skeletons with the cancer rates of today's 60 year olds.

nemo44x 5y ago
It’s amazing how precarious being born is. I think I read that about 200 years ago around 40% of people didn’t make it past 5 years old or something like that. Antibiotics have helped a lot in modern times, especially for mothers giving birth.
- retrac 5y ago
  The improvement in child survival is attributed to many things, but it may be a mix of vaccinations, less indoor air pollution, much better hygiene, better nutrition, and perhaps just better parenting. (People have had some very peculiar ideas on how to care for and raise children; I wouldn't be surprised if in hindsight our distant descendants consider us woefully inadequate in that regard too.) Most of the progress, in absolute terms, with reducing maternal mortality and the infant/toddler death rate in the industrialized countries was actually made before antibiotics were developed, in the late 19th / early 20th centuries. In England in 1851 about 26% of children died before the age of 5, falling to 23% in 1891, 19% in 1911, 11% in 1921, 9% in 1931, and 7% in 1941 (and then we're in the antibiotics era).
- inglor_cz 5y ago
  From a pair that has been undergoing IVF treatment since November 2019: it is very precarious. There are a lot of opportunities to die before someone draws their first breath.
- devoutsalsa 5y ago
  Infant mortality was 165 deaths per 1000 births in the year 1900, according to this... https://www.pbs.org/fmc/timeline/dmortality.htm https://www.pbs.org/fmc/timeline/dmortality.htm ...I also like the link to play the video via Real player in the upper left corner :)

7952 5y ago

I think evolution plays a part in why older people are more prone. A debilitating illness in your teens is likely to stop you reproducing and is more likely to vanish. But a genetic trait for cancer later in life can get past on.

adolph 5y ago
There must be some evolutionary fitting function that mutations serve that have prevented them from being selected out.
- HarryHirsch 5y ago
  Amongst the ""hallmarks of cancer" (there's a pair of papers with that title) is tissue invasion, angiogenesis and immunosuppression - and there are genes for that because the placenta needs those so the fetus can survive and reach term. What I'd really like to know is incidence of cancer in marsupials, birds and fishes, one would predict it to be markedly lower.
- yuliyp 5y ago
  The rate of mutation is significantly lower in humans than in say viruses. Being able to adapt eventually to changing circumstances is valuable.
- pfdietz 5y ago
  And in very large animals there are adaptations that keep cancer in check, even though they have many more cells. IIRC, elephants have many copies of genes that induce suicide in aberrant cells.
- mcguire 5y ago
  Not entirely on point here, but you should look at that the other way around: mutations are retained unless they cause adverse consequences that result in them being selected out.
siggen 5y ago
Medawar effect

fpoling 5y ago

Also, even if the low average life expectancy was due to excessive mortality among children with chances to live up to 70 once one reached 40 not much different than today, it still does not imply that cancer rates were lower. It could be very well that it is those people who would die as newborn or children without modern medicine and access to clean water have bigger chances of getting cancer with age.

rtkwe 5y ago

Life expectancy is a tricky number to compare across long spans of time because it's heavily influenced by people dying young which was much more common in the past than it is now, people did die earlier but it's not as bad as a say 40 year life expectancy would make it seem because that number is dragged down by lots of early childhood deaths.

ineedasername 5y ago
Yes, in 1800, even in more developed countries at the time, about 30% of kids died by age 5. And being pregnant was frequently fatal as well, with nearly 1 in 10 pregnancies killing the mom.

dheera 5y ago

Not only that, but I imagine in pre-industrial times, those who got currently-curable forms of cancer didn't get cured during those times, and Darwinian forces stopped them from reproducing. There isn't a necessarily good or bad here but those Darwinian forces did eliminate a lot of genetic defects from the population before modern medicine. In the future though we might be able to yet again eliminate defects not by natural selection but by gene editing while still allowing those individuals to carry on a normal life.

tejtm 5y ago

Not a biologist, but been around them long enough. I been cultivating a theory that mammals strategy is more or less "go fast; break things". That is, asteroid or not, we were on track to out evolve everything that came before by extending and exploiting explosive cell growth. No animal converts matter & energy to body-mass faster than young mammals, the cold blooded do not stand a chance. The competition would get larger eventually only if some adolescent mammal did not eat them first as peers. consider how you would bet on a 1 year old raccoon vs a 1 year old alligator then again with a 5 year old raccoon vs a 5 year old alligator The mammal strategy traded the long game for the quick win. We have all sorts of (genetic) machinery who's function is to grow fast but then STOP as we can't support gigantic sizes. (Maybe in part because of the quick and dirty foundations but thermodynamics have scaling issues too) So we need to shut of all those machines before we get too big. And so here we happily sit in our bodies, our mammal factory and everything is great; just don't push that big red button over there, or pull that lever or that one or that one or ... eventually if you live long enough some of those buttons will be pushed and the mammal machinery will do what it evolved to do. grow fast and break things. A final observation on humans in particular, recently bipedal, have not gotten all the bugs worked out on that. Deployed a monkey patch for dimorphic gender singling requires cron job flipping on a subset of growth machinery some years after the main global shutdown but only flip them on for a season or so; still seeing evidence of switch bounce issues, see ticket BCRA1.

Kejiti 5y ago
We humans are very unique though on how much care and dependency babes need. From an evolutionary perspective natur might have just stoped after we gave birth but for humans you need to be still very healthy for much longer. We have a second evolution which we as a species gained due to our more generic and bigger brain and therefore being able to retain and learn more even through generations. Whenever nature stoped we continued (glasses, cancer treatment etc.) I personally would not subscribe to your idea that cancer is our basis and we just let loose. Cancer is just one sickness of a highly complex system. And after all why would longevity even be a goal for evolution? It's a wishful human idea of lifing forever. I myself I'm looking forward to NOT life forever and still today the thought of not being able to end my life for good is my worst nightmare next to loosing my mind.

nradov 5y ago

Yes if you live long enough eventually some kind of cancer will kill you. This is inevitable due to accumulating cellular damage. Someday it might be possible to repair that damage but it's not clear how.

dsjoerg 5y ago

Your objection is correct, and none of the responses you've received so far seem to have understood your point. I went ahead and read the actual published paper (https://acsjournals.onlinelibrary.wiley.com/doi/epdf/10.1002/cncr.33615 https://acsjournals.onlinelibrary.wiley.com/doi/epdf/10.1002...) and it is just as statistically naive as the NatGeo article made it sound. Let's cartoonishly oversimplify cancer so that we can see how life expectancy would affect observed statistics. Let's say cancer occurrence is 0% for people up to age 40, and then starting on the 40th birthday, cancer occurrence is 10% per year. Everyone who gets cancer dies immediately. Then, imagine that life expectancy in 1500 was 25 years old, standard deviation 10 years (yeah lognormal blah blah just go with it). So, most people don't live to 40, but the ones who do sometimes get cancer. But then, after 1500, life expectancy mean increases by 0.1 years per year. By the year 2000, life expectancy is 75 years old! Much more cancer is going to happen! Many more of the deaths will be from cancer! Cancer itself didn't change. So, these researchers see a lower cancer rate in the bones they're looking at, but they need to do some MATH on the ages these bones and of modern humans to know how to compare cancer rates then to cancer rates now.

underwater 5y ago
Life expectancy in the 1500s was much higher if you discard infant mortality. Like 55 years, not 25.
- zdragnar 5y ago
  Cancer rate after 40 is also not 10% per year. It is a reasonable simplification to demonstrate the point.
  - underwater 5y ago
    If you just make up numbers to create a hypothetical model to explain an observation that's fine. But then it's just a theory. Sebb suggested that lower life expectancy leads to less cancer. Dsjoerg defined a hypothetical model that would lead to that happening, and then said that proves Sebb was correct. That's just circular reasoning. And when the hypothetical doesn't match observed reality it's a sign it might be broken.

Spooky23 5y ago

There were plenty of old people. Life expectancy was skewed by childhood death and urban poor and wasn’t as grim as we think. (Most people lived outside of urban areas) One big thing to consider is how would an 18th century person know they had leukemia? Cancers that don’t have a physical manifestation were probably classified as some other mysterious malady.

m463 5y ago

I remember reading about a drug study where people were given a drug for <something> (I don't recall) and people started dying of heart attacks. Turns out it was curing the <something>, but the next thing the population would statistically die of was: heart attacks.