Source: The Saturday Mercury, 31 March, 2001, p.21


All downhill from chubby children

SCIENCE WATCH with STANLEY ROBERT
 
HUMANS, especially in developed 
countries, are living longer than we 
ever have before. This can mostly be 
put down to better nutrition, 
vaccination, antibiotics, sewers and 
clean drinking water. 
 
   In an apparent contradiction, we 
have also been hearing that people 
currently alive, especially children, 
are fatter than ever before. 
 
   Are we at the crest of our 
achievement in regard to human 
lifespan? Will the current crop of 
chubby children bring down our 
life-expectancy averages in the next 
few decades? 
 
   It will be interesting to see if 
medicine can keep up with our 
lifestyle diseases-usually caused by 
the overeating and underexercising 
parts of our lifestyle. 
 
   Of course, the simplest way to 
reduce the risks of lifestyle disease is 
to modify one's lifestyle. 
 
   Several studies published over the 
past week appear to report the 
blindingly obvious. However, given 
that humans in developed countries 
keep getting fatter, maybe we need 
more and more reminding of these 
obvious findings. 
 
   The results of a large-scale US 
survey showed that there was a 
positive correlation in children 
between watching television and 
obesity. 
 
   Children who watched more than 
four hours of television a day, aside 
from having hopeless parents, were 
2.6 times more likely to be obese 
than those who watched less than 
one hour a day. 
 
   Presumably there just isn't enough 
time in the day for such ravenous TV- 
watchers to also get some exercise. I 
guess that similar risks would apply 
to children spending hours on the 
computer or reading books. 
 
   However, it seems to me that most 
bookworms have a better sense of 
balance than do TV addicts. 
 
   A long-term study from Finland 
provides another example of what 
everyone expects. 
 
   Fitter men have lower incidences 
of death by heart disease. 
 
   In fact, in their observations of 
arbitrarily defined fit and unfit men 
over 10 years, the researchers found 
that unfit men had a three-fold 
increased risk of dying from heart 
disease and a 2.7-fold increased risk 
of dying by some other means. This 
is a very big difference! 
 
   In case you're now worried that 
you're going to die because you're 
unfit, another American study 
suggested that you don't have to do 
all that much to start reducing your risk 
of death by heart disease. 
 
   In women (that's all the researchers 
looked at here) the risks started 
dropping when only one hour of 
light walking a week was done. Of 
course more exercise is better. 
 
   Another aspect of modern lifestyle 
that contributes to human disease is 
tobacco smoking. There's plenty of 
evidence that it's a good way to 
reduce lifespan. 
 
   One more subtle aspect of cigarette 
smoking is the effect on the skin. 
Have you noticed that many smokers 
look more wrinkly and older than 
they actually are? 
 
   Researchers from Germany and the 
UK analysed skin from the buttocks 
of smokers and nonsmokers for 
levels of an enzyme called MMP-1. 
 
   It is known that MMP-1 destroys 
collagen in skin that has been 
exposed to UV radiation, which 
explains why sunbathers become 
wrinkly. 
 
   The researchers looked at buttocks 
not because they were naughty but 
because most buttocks do not get 
exposed to UV radiation. They found 
that smokers' buttocks contained 
MMP-1 while nonsmokers' did not. 
 
   This suggests that wrinkles from 
smoking are caused by the same 
mechanism as wrinkles from 
sunbathing, which, by the way, is a 
lot cheaper. 
 
· Stanley Robert has a PhD in genetics and gained a 
post-doctoral fellowship at the University of 
Washington, Seattle.


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