FOR some youngsters, a longing look at skinny models such as Kate Moss can
literally make them go weak at the knees.
A bad diet or eating disorders are already known to weaken girls’ bones. Now
it seems that simply worrying about weight can release hormones that lead to
weaker bones.
Susan Barr and Jerilynn Prior of the University of British Columbia in
Vancouver, Canada, quizzed 51 healthy pre-teen girls, none of whom had eating
disorders, about weight worries. They also measured the mineral content of the
girls’ bones using a low dose of X-rays. To their surprise, they found that the
girls who were more concerned about their weight than average were significantly
more likely to have lower bone densities.
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Most differences in bone content are determined by genetics, says Barr, and
the next biggest determinant is height. But the researchers found that worry
could account for about 8 per cent of the differences in bone density. This was
about the same percentage as the difference due to the girls’ stages of
puberty.
It may not be a huge percentage, the authors say, but with about one-third of
women over the age of 50 suffering fractures related to osteoporosis, or low
bone density, even small factors can have a large effect on public health. “Over
a lifetime,” says Barr, “this could be a determinant of who gets osteoporosis
and who doesn’t.”
“I think they’re touching on one of the crux questions,” says Nicola Keay, a
researcher at Britain’s National Osteoporosis Society. “I’m sure stress is a
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Work by Barr and Prior’s colleague Judy McLean suggests that college girls
who fret too much have higher than usual levels of urinary cortisol, a stress
hormone that has a negative effect on bone development. While it’s “a bit of a
leap” to relate those results to pre-teens, says Barr, the same thing may be
happening with weight worries.
With most women in developed countries apparently already worrying about
their weight, their job or their boyfriend, this study presents them with yet
another dilemma: should they worry about these results or just ignore them?