Sorry to be a bore on this topic, but it occurred to me last night
that if life span is indeed maternally inherited in part, then there
may be an association between maternal age at conception and the life
expectancy of offspring. The thinking behind this is related to female
meiotic pattern in which oocytes proliferate prenataslly and then enter
a prolonged resting stage of M1, not reactivating until just before
ovulation. There are well documented effects of maternal age on oocyte
fertility and on chromosomal defects such as Downs syndrome. Aging
oocytes might well acccumulate increased levels of defective mtDNA.
While it would be very difficult to sort out lifestyle factors, this
hypothesis would predict that in general younger siblings would live
longer than older. Anyone in the group know of data that evaluates
life expectancy in terms of birth order? Wonderful research area for a
dedicated nutty epidemiologist!
Jim Cummins
School of Veterinary Studies
Murdoch University
Western Australia 6150 Tel +61-9-360 2668 Fax +61-9-310 4144
For every complex problem there's a simple solution. And it's wrong!
