Second-hand smoke increases the
risk of the bone disease osteoporosis, researchers
have found.
The US/Chinese study showed exposure
to passive smoking boosted pre-menopausal women's
osteoporosis risk threefold.
An International Osteoporosis
Foundation meeting in Toronto, also heard men,
as well as women, increase osteoporosis risk by
smoking.
Experts said the studies added
to understanding of the link between smoking and
the bone disease.
Osteoporosis,
which affects one in three women and one in 12
men, is responsible for 200,000 broken bones per
year in the UK - and 40 deaths a day.
It is often known as a silent
illness because many people do not know they have
it until it is too late.
Although it is thought of as
a disease of old age, its roots are thought to
lie in adolescence.
Harvard School of Public Health
researchers looked at over 14,000 men and pre
and post-menopausal women in rural China.
The scientists measured hip bone
mineral density, and recorded non-spine fractures
and smoking history.
Second-hand smoking was defined
as living with one or more people who smoked each
day.
Pre-menopausal non-smoking women
who lived with one smoker had more than double
the risk of osteoporosis compared to those who
lived with none.
And those who lived with two
or more smokers exposed to second-hand smoke were
found to have a threefold greater risk of the
condition.
They also had a 2.6 times greater
risk for a non-spine fracture, compared to non-smokers.
Dense bone
A separate study by Gothenburg
University researchers looked at 1,000 men aged
between 18 and 20-years-old .
It was found that smokers' bone
density in the spine, hip, and body as a whole,
was lower than in their non-smoking peers.
A CAT (Computer Tomography) scanner
was used to obtain 3D images of bone.
The researchers say smoking appeared
to primarily affect a specific type of bone called
cortical bone, by reducing its thickness.
This very dense bone forms a
layer, similar to the enamel on teeth, around
softer, spongy bone.
The effects was most striking
in the hip, where the mineral density was over
5% lower than in non-smokers.
Fractures are more common in
people with low bone mineral density.
'Interesting addition'
A spokeswoman for the UK's National
Osteoporosis Society said: "We know that smoking
is becoming a much more significant risk factor
for predicting whether you will break a bone because
of osteoporosis due to the increasing amount of
research being done into this area.
"However, our understanding of
the effects of passive smoking on bone health
is not quite so well researched so this study
is an interesting addition to our cumulative knowledge
of what smoking does to our skeletons.
"It does all add up to the fact
that smoking is just plain bad for bones, whether
you smoke yourself or if you live with someone
who smokes.
"So it's another good reason
to consider either giving up yourself or encouraging
and supporting your loved ones to quit."
Amanda Sandford, of Action on
Smoking and Health (ASH) said: "If there is a
link between actual smoking and a condition, it's
not surprising if a further link is found between
passive smoking - albeit at a lower rate.
"The carcinogens in tobacco smoke
can affect any organ of the body, once it's absorbed.
"This is further evidence for
a ban in public places."
