Re: News at <http://longevity-science.org/>

Tim Tyler <[EMAIL PROTECTED]>  wrote in message news:<[EMAIL PROTECTED]>...
> In sci.life-extension Leonid Gavrilov <[EMAIL PROTECTED]> wrote or quoted:
> > Tim Tyler <[EMAIL PROTECTED]>  wrote in message news:<[EMAIL PROTECTED]>...
> >> Leonid Gavrilov <[EMAIL PROTECTED]> wrote or quoted:
>  
> >> > "Does Exceptional Human Longevity Come With High Cost of Infertility?
> >> > Testing the Evolutionary Theories of Aging"
> >> > http://longevity-science.org/IABG-Gavrilova.html
> >> 
> >> I enjoyed this one - my thoughts:
> >> 
> >> The paper says:
> >> 
> >> ``What is really important is that the chances of being childless do not
> >>   demonstrate any increase for long-lived women (lifespan 90+ years).''
> >> 
> >> From the graph, it /does/ seem like there is an increase in the > 80 yo
> >> groups - though its significance is not clear.
> > 
> > *** The error bars provided at this graph indicate that there is no
> > any statistical significance in this small fluke.
> 
> A more conventional way of presenting such a result would be to write:
> 
> ``What is really important is that the chances of being childless do not
>   demonstrate any significant increase for long-lived women [...]''


*** Yes, I agree, thank you!


> >> My other thought is that it would be nice to have data for other
> >> population areas.
> >> 
> >> The idea that there is a trade-off between reproductive success and
> >> longevity is largely based on allocation of limited resources.
> >> 
> >> Ladies in european aristocratic families may be relatively less
> >> likely to experience resource shortages as a result of expenditure
> >> on children - and so might avoid much of the resulting impact on
> >> their lifespans - by being better equipped financially than most
> >> members of the population.
> >> 
> >> The other obvious bias in the sampling is the one towards females.
> > 
> > *** Please elaborate in more detail, where have you found an obvious
> > bias towards females in our study.
> 
> Only women were sampled:
> 
> ``The dataset is comprised of 3,723 married women born in 1500-1875 and
>   belonging to the upper European nobility. Every case of childlessness
>   was cross-checked using at least two different sources. Data analyses
>   were based on logistic regression model using childlessness as a
>   dependent (outcome) variable, and woman lifespan, calendar year of
>   birth, age at marriage, husband's age at marriage and husband's lifespan
>   as dependent (predictor) variables. We found that woman's exceptional
>   longevity does not increase her chances to be infertile.''


*** Please note that all women in this study had husbands (males),
thus there is *NO* bias towards females in our dataset.

I agree however that a similar analysis could done for males on
possible links between their longevity and infertility -- this work is
in progress now.

Thank you for your interest and useful comments ! 

Kind regards,

 -- Leonid Gavrilov 
Author of the book "The Biology of Life Span"
 http://longevity-science.org/index.html#Book