

Children Born to Older Fathers and Grandfathers May Live Longer - SlipperySlope
http://extremelongevity.net/2012/06/13/children-born-to-older-fathers-and-grandfathers-may-live-longer/

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saurik
(edit:) As quite rightly pointed out by stiff, this summary article is
actually not lying to us, as its final sentence _does_ explicitly and
correctly pointed out that this paper's goal was actually not to attempt to
establish any kind of causation here. I will not delete or edit the rest of my
comment here, but I would recommend disregarding it.

People who live longer are more likely than people who die young to have
children while they are old. People who are children of people who genetically
live long are more likely to themselves genetically live long. Thereby it
would be surprising--downright shocking (in the scientifically-exciting "time
to reevaluate what kinds of traits can be passed down by genes" sense)--if we
did not find the statistically significant correlation that people born to
older people tend to be genetically able to live longer than people born to
young people.

FTR, The paper even admits the possibility of this selection bias, but then
seems to just disregard it with a "regardless" as, despite this headline and
summary, the paper seemed more excited by the increased evidence that TL was a
good marker of longevity. I hate the way people describe science. :(

~~~
ajross
It's all well and good to question statistics, but:

> People who live longer are more likely than people who die young to have
> children while they are old.

That's a statement with pretty poor support. Certainly the median childbearing
age is _well_ within the lifespan of even short-lived people. The relative
population of fathers who have children at 40 is not meaningfully increased by
the number of people who died before 40 of correlating/age-related illness
(staying with the hypothesis from the article: people basically don't die
before 40 because of the length of there telomeres). Frankly my intuition says
that the effect you posit is going to be near-zero. Do you have any numbers?

If you're going to criticize, do it right.

~~~
saurik
Actually, no: I will contend I am "doing it right". I am not arguing that my
explanation is true (if I were, I'd be just as bad as these people I'm ranting
about); I only will claim that my explanation is obvious and reasonable and
thereby has to be considered and explicitly countered or controlled for before
you can just assume that it is due to something else.

I totally accept that it /might/ be true that if you are older when you have
children, the children will live longer, but this paper does not demonstrate
that. That said, I don't even think the researchers of this paper were
/really/ attempting to demonstrate that, and so I will put the blame squarly
on this "Extreme Longevity" site for not paying enough attention.

(edit:) Actually, while I maintain that ajross' commentary was unhelpful (as I
stand by my first paragraph in this comment), as pointed out by stiff this
article does conclude with an explicit note discounting the notion that this
article is establishing causation.

~~~
ajross
Except that, as I point out, your explanation is neither obvious nor
reasonable (frankly, I'd say it's flat wrong). Yet you introduced it without
evidence anyway as a way of saying "What about this?". That's the same
technique creationists use to "challenge" evolution. You can't make that
argument, logically, with a flawed counter hypothesis.

The only reason I posted is that you got uppity in your final sentence,
complaining about journalists lack of statistical sense. Frankly, yours is no
better.

~~~
saurik
As I explicitly stated, the authors of the paper actually agreed that this was
a sufficiently interesting selection bias to note (although not to bother
refuting, as far as I can see; they just say that that if that were true then
sperm TL would be an interesting marker, and then move on with a
"regardless").

> It is possible that older men who volunteer to donate sperm have better
> reproductive health and longer sperm TL _and that a similar selection bias
> results in men with longer sperm TL tending to reproduce at later ages_.

For more context on my general crusade against poor science reporting, I
encourage you to read my comment history. (In which case, I will claim your
snark about believing in evolution is ironic. I contend and argue that it is
publishing summary headlines like this that makes people not believe in other
science, such as evolution.)

<http://news.ycombinator.com/item?id=4082886>

------
reasonattlm
You might look on this in the context of work on selective breeding of flies
at older ages by Michael Rose:

[http://www.fightaging.org/archives/2011/04/the-work-of-
micha...](http://www.fightaging.org/archives/2011/04/the-work-of-michael-
rose.php)

Variability of longevity in response to changing circumstances persists across
generations for calorie restriction and age of childbirth in a range of
laboratory species, so we should not be completely surprised to see some signs
of that in human populations. The trick has always been to be able to peel
that away from the confounding factors. (And you can argue over whether this
paper manages to do that sufficiently well).

From an evolutionary perspective it makes perfect sense for organisms to
adjust for longevity or a fast burn in response to environmental changes.
Species that are able to do this should be more successful, and this is an
old, old set of machinery - as shown by the fact that is shared with flies,
yeast, and so forth.

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simulate
This story was submitted two days ago:
<http://news.ycombinator.com/item?id=4099940>

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trebor
I'd like to see an explanation of how this matters in plain English. I'm not
sure what 0-1 in telomere length is, in relation to years, but the difference
the chart reveals is less than 1/10th of a percent. The bias in the chart
alone makes it seem huge.

Then I'd like to know if the telomere "consumption" rate is constant (I doubt
it). Because unless its constant, this just leads to our potential maximum
lifespan—not the expressed lifespan (due to stress, diet, etc). Like
genotype/phenotype differences.

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cdooh
I once read somewhere that the after a certain age, like 50 or something, the
less quality you sperm is and hence your kids. So would this be the trade off?

------
excuse-me
"people in the Philippines"

So no chance that older father = more education = better job = more money =
better healthcare, compared to teenage parents?

~~~
Travis
I just quickly skimmed the published paper, but it looks like they controlled
for standard demographic variables.

