Releases Saturday 24 August 2002
No 7361 Volume 325
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(1) SCREENING REDUCES MASTECTOMY RATES
(2) MOULDS INCREASE SEVERITY OF ASTHMA
(3) GASTROINTESTINAL
SYMPTOMS NOT LINKED
TO LATER AUTISM
(4) IS
GOVERNMENT HEALTH POLICY BASED ON
EVIDENCE OR
ASSUMPTION?
(1) SCREENING REDUCES MASTECTOMY RATES
(Are breast cancer screening programmes
increasing rates
of mastectomy? Observational study)
http://bmj.com/cgi/content/full/325/7361/418
The introduction of breast screening has
brought about a
reduction in mastectomy rates, despite
recent suggestions
that screening increases the number of
mastectomies as a
result of overdiagnosis, say researchers
in this week's
BMJ.
Between 1990 and 1996, over 59,000 women
aged
50-69 years were invited to at least one
breast screen as
part of the Florence mammographic screening
programme. Changes in rates of radical
surgery and
incidence of breast cancer since the introduction
of the
screening programme were analysed.
Rates of breast conserving surgery were
1.18 per
thousand in 1990 and 1.87 per thousand
in 1996. In
1990, the rate of mastectomy was 1.08
per thousand,
whereas in 1996 it was 0.62 per thousand.
The rate of breast conserving surgery has
increased
significantly with the advent of screening,
and the rate of
radical surgery has declined significantly,
say the authors.
Similar reductions in mastectomy rates
have been
observed elsewhere.
This indicates that the introduction of
screening brings
about a reduction in mastectomy rates,
not an increase,
they add. Follow up will continue to ascertain
whether
these findings are maintained.
Contact:
Marco Zappa, Senior Epidemiologist, Unit
of
Epidemiology, Centre for the Study and
Prevention of
Cancer CSPO, Florence, Italy
Email: m.zappa{at}cspo.it
(2) MOULDS INCREASE SEVERITY OF ASTHMA
(Sensitisation to airborne moulds
and severity of asthma:
cross sectional study from European
Community
respiratory health survey)
http://bmj.com/cgi/content/full/325/7361/411
Severe asthma in adults may be associated
with
sensitivity to airborne moulds rather
than pollens, finds a
study in this week's BMJ.
Researchers used data from 1,132 people
with asthma
from the European Community respiratory
health survey
to access whether the severity of asthma
is associated
with sensitisation to airborne moulds
rather than to other
allergens, such as pollens and cats.
Sensitisation to moulds was significantly
associated with
severity of asthma, but the team found
no association
between severity of asthma and sensitisation
to pollens or
cats.
The small size of fungal spores may allow
them to reach
the lower airways, suggest the authors.
Unlike pollens,
moulds are also present through the year
with increase in
the spore counts during the autumn months.
Furthermore,
the level of mould exposure is probably
greater because
the exposure occurs indoors rather than
outdoors and
people spend most of their time indoors.
Those people with asthma who are sensitised
to airborne
moulds should be educated to pay careful
attention to
symptoms and comply with treatment, particularly
during
the seasonal increase in mould spore counts,
say the
authors.
Patients should also be encouraged to decrease
exposure
by avoiding indoor conditions that facilitate
the growth of
moulds ? for example, by better ventilation
and by
decreasing dampness, they conclude.
Contact:
Mahmoud Zureik, Epidemiological Researcher,
National
Institute of Health and Medicine Research
(INSERM),
Paris, France
Email: zureik{at}vjf.inserm.fr
(3) GASTROINTESTINAL
SYMPTOMS NOT LINKED
TO LATER AUTISM
(Relation of childhood gastrointestinal
disorders to
autism: nested case-control study
using data from the UK
General Practice Research Database)
http://bmj.com/cgi/content/full/325/7361/419
Children with autism are no more likely
than children
without autism to have had gastrointestinal
disorders,
finds a study in this week's BMJ.
Researchers at Boston University identified
96 children
with autism from the UK General Practice
Research
Database between 1988 and 1999. Each case
was
matched with up to five children without
autism. They
also considered the time relation between
measles,
mumps, and rubella vaccination and the
onset of
gastrointestinal symptoms among the cases.
They found no increase in a history of
gastrointestinal
disorders, coeliac disease, food intolerance,
or recurrent
gastrointestinal symptoms among children
with autism
compared with those without autism. They
also found no
temporal association between measles,
mumps, and
rubella vaccination and the onset of gastrointestinal
symptoms in children with autism.
The authors cannot exclude the possibility
that some
children in the study had subclinical
gastrointestinal
symptoms before their presentation with
autistic
behaviour. However, the children described
by
Wakefield and colleagues had symptomatic
gastrointestinal disease.
They also cannot exclude the possibility
that severe
gastrointestinal disease may be associated
with the
development of autism in certain individuals.
However,
their results indicate that if this occurs,
it is likely to be
uncommon.
"Our results are consistent with those
of other studies in
providing evidence against a substantial
association
between gastrointestinal illness in children
and the later
development of autism," they conclude.
Contact:
Corri Black, Research Associate, Boston
Collaborative
Drug Surveillance Program, Boston University
School of
Medicine, MA, USA
Email: cxb2{at}ph.abdn.ac.uk
(4) IS GOVERNMENT
HEALTH POLICY BASED ON
EVIDENCE OR ASSUMPTION?
("Food deserts" � evidence and assumption
in health
policy making)
http://bmj.com/cgi/content/full/325/7361/436
The overinterpretation of a few small scale
studies,
carried out up to 10 years ago, could
end up being used
to determine health policy because the
findings fit in with
the government's broader policy objectives,
argue
researchers in this week's BMJ.
Steven Cummins and Sally Macintyre examine
the
phenomena of "factoids" ? assumptions
or speculations
reported and repeated so often that they
are considered
true. Using the widely claimed existence
of "food
deserts"? poor urban areas in the United
Kingdom where
residents cannot buy affordable, healthy
food ? they raise
important questions about how evidence
in public health
is produced, interpreted, and reproduced
when making
health policy.
Three main studies have been used as evidence
that food
deserts exist in the UK, yet the authors
suggest that this
research may have been overinterpreted
to suit the needs
of individuals or groups, and subsequently
cited in
journals, at seminars, and in the media
without close
reference to the original source material.
If these three studies had concerned an
issue not so
eagerly espoused by many in central and
local
government and public health, and by the
public too, and
if the issue had been more contentious,
the authors
suspect that the studies would have been
more critically
appraised.
The key problem is that the burden of proof,
or demand
for evidence, may vary according to a
policy's perceived
fit with current collective world views,
they add.
As such, policy makers need to move away
from an
unquestioning acceptance of conventional
wisdom and
"expert" advice and cast a more critical
and objective eye
over the facts, they conclude.
Contact:
Steven Cummins, Research Associate, MRC
Social and
Public Health Sciences Unit, Glasgow,
Scotland
Email: steven{at}msoc.mrc.gla.ac.uk
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