Stindl R.
Institut
fur Medizinische Biologie, Medizinische Universitat Wien, Wahringerstrasse 10, 1090 Vienna, Austria. reinhard_stindl@yahoo.de
The
classic explanation that women outlive men solely due to hormonal and lifestyle differences, does not withstand a critical
analysis. In developed countries, the average gap in life expectancy between the sexes is 7 years. It has widened over the
last decades, despite the trend of women copying the 'unhealthy' lifestyle of men. Estrogen levels in postmenopausal women
are virtually identical to estrogen levels in males and can hardly explain the discrepancy. Furthermore, testosterone got
its bad reputation from one study on mentally retarded men, which has to be interpreted with caution. However, sexual size
dimorphism with men being the larger sex in conjunction with the limited replication potential of human somatic cells might
account for higher mortality rates in males, especially at old age. The hypothesis, as presented here, is based on the well-known
concept of a cellular mitotic clock, which was discovered by Leonard Hayflick almost half a century ago. The underlying counting
mechanism, namely the gradual erosion of chromosome ends (telomeres) due to the end replication problem of linear DNA molecules,
was first described by Alexey Olovnikov in 1971 and with minor modifications has become a widely accepted paradigm. In a recent
Lancet study, an inverse correlation between mean telomere length and mortality in people has been found. In this and two other studies, it was confirmed that males do have shorter telomeres than
females at the same age. This is almost certainly a consequence of men being usually taller than women, although nobody has
done an investigation yet. Clearly, a larger body requires more cell doublings, especially due to the
ongoing regeneration of tissues over a lifetime. Accordingly, the replicative history of male cells might be longer than that
of female cells, resulting in the exhaustion of the regeneration potential and the early onset of age-associated diseases
predominantly in large-bodied males. Inherited telomere length variation between unrelated individuals might have obscured
a clear correlation between body height and mortality, leading to conflicting results in some studies. Finally, I propose that the secular height increase over the last decades, of about 2.5
cm per generation in the western world, has to be blamed for the widening of the gender gap in life expectancy.
PMID: 14729022 [PubMed - indexed for MEDLINE
Life Sci. 2003 Mar 7;72(16):1781-802
Is height related to longevity?
Samaras TT, Elrick H, Storms LH.
Reventropy Associates, 11487 Madera Rosa Way, San Diego, CA 92124-2877,
USA. SamarasTT@AOL.com
Over the last 100 years, studies have provided mixed results on the mortality and health of
tall and short people. However, during the last 30 years, several researchers have found a negative correlation between greater
height and longevity based on relatively homogeneous deceased population samples. Findings based on millions of deaths suggest
that shorter, smaller bodies have lower death rates and fewer diet-related chronic diseases, especially past middle age. Shorter
people also appear to have longer average lifespans. The authors suggest that the differences in longevity between the sexes
is due to their height differences because men average about 8.0% taller than women and have a 7.9% lower life expectancy
at birth. Animal experiments also show that smaller animals within the same species generally live longer. The relation between
height and health has become more important in recent years because rapid developments in genetic engineering will offer parents
the opportunity to increase the heights of their children in the near future. The authors contend that we should not be swept
along into a new world of increasingly taller generations without careful consideration of the impact of a worldwide population
of taller and heavier people.
A Finish study
of Olympic athletes shows an increase in life expectancy of around 2.5 years. Possible
the failure for greater improvement was related to the height of the athletes since most sports favor height. Weight lifters, though possible not taller, are broad-boned; viz., they have more cells and thus are equivalent
as per number of cells to people several inches taller than them
Another tidbit
of interest is that taller people have lower incidents of coronary thrombosis, the leading cause of death. Of course
if they are quite tall then the load on the heart from the serving a larger body more than counteracts this effect.
Another tidbit,
tall people, having more cells have a higher incidents of cancer.--jk