Health
29 July
2010 Last updated at 22:59 GMT
Calcium
pills 'increase' risk of heart attack
By Emma
Wilkinson
Health
reporter, BBC News
Calcium
supplements taken by many older people could be increasing their risk of a
heart attack, research shows.
The study,
in the British Medical Journal, said people who took supplements were 30% more
likely to have a heart attack.
Data from
11 trials also suggested the medicines were not very effective at preventing
bone fractures.
Almost 3m
people in the UK are thought to have osteoporosis and many take calcium pills
to prevent fractures.
The study
recommends doctors review their use of calcium supplements for managing
osteoporosis.
The
National Osteoporosis Society said most people should be able to get enough
calcium through their diets, rather than reaching for the medicine cabinet.
The
researchers said those who had a diet naturally high in calcium were at no
increased danger.
'Limited
benefit'
In all
12,000 people aged over 40 took part in the trials of calcium supplements of
500mg or more a day.
The risk of
heart attack was seen across men and women, was independent of age and the type
of supplement given.
A small
increased risk of death was seen in the study but was not statistically
significant, the researchers said.
The reason
for the increased risk of heart attack is not clear but it is thought the extra
calcium circulating in the blood could lead to a hardening of the arteries.
Calcium in
the diet is safe and the Food Standards Agency recommends adults have 700mg of
calcium a day from milk, cheese and green, leafy vegetables.
Dr Alison Avenell, from the University of Aberdeen which did the
research with colleagues in New Zealand and the US, said the evidence suggests
calcium supplements only have a limited benefit in preventing fractures,
especially when compared to other treatments available.
"It is
a balance of risks - people should consider the risks involved and how they
apply to their own circumstances and discuss the matter with their GP," she
said.
She added
the results did not necessarily apply to younger people with conditions for
which they take calcium.
Judy
O'Sullivan, senior cardiac nurse at the British Heart Foundation, said the
results should be interpreted with caution because the trials did not set out
to look at the risk of heart attack.
"However,
the research should not be completely ignored," she said.
"Any
new guidelines on the prevention of fractures in those most vulnerable to them
should take this type of analysis into account."
Dr Claire
Bowring, of the National Osteoporosis Society, said: "We've always
recommended that people should aim to get the calcium they need from their diet
to help build stronger bones.
"If
you get all of the calcium that you need from your diet and adequate vitamin D
from exposure to sunshine, then a supplement will not be necessary."
She said
there were still questions to be answered about the treatment of osteoporosis
but advised people taking calcium supplements to talk to their GP, especially
if they have a heart condition.
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