Pollution May Be Key to Rise in Childhood Leukaemia

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Mon 6 Sep 2004

 

5:59pm (UK)

Pollution May Be Key to Rise in Childhood Leukaemia

 

By Lyndsay Moss and Jennifer Sym, PA News

http://news.scotsman.com/latest.cfm?id=3462038

 

 

Pesticides and other environmental pollution may affect unborn children –

and play a role in the rising rates of childhood leukaemia, new research

suggested tonight.

 

A study, unveiled today at the First International Scientific Conference on

Childhood Leukaemia in London, indicated harmful environmental agents can

cross the placenta from mother to foetus.

 

The study suggests the transfer could affect the immune system of the

child, which could be linked to the increasing incidence of the disease.

 

Children in the womb are particularly sensitive to environmental agents,

the scientists found, after carrying out tests on donated human placentas

and pregnant guinea pigs.

 

The paper was released as experts warned that falling numbers of deaths

from childhood leukaemia had diverted attention away from rising rates.

 

Professor Alan Preece, Professor of Medical Physics at the University of

Bristol, said: “We think it has an affect on immunology which is possibly

linked to leukaemia.

 

“We found that foetal organ concentrations can exceed those of the mother

which may have implications due to the increased sensitivity of the foetus.

 

“The exact levels are as yet unknown but we know that childhood leukaemia

is initiated in utero and this could well be a factor in the initiation.

 

“Consideration must now be given to the likely risk estimates.”

 

A Department of Health spokeswoman said: “We welcome the research coming

out on risk factors associated with leukaemia and support the debate

surrounding this issue.

 

“The Department of Health has contributed considerable funding to this type

of research as an important area of medical knowledge to develop.”

 

Some 500 youngsters under the age of 15 are diagnosed with leukaemia in

Britain each year, with about 100 children dying.

 

Leukaemia accounts for about a third of all cancers in children, and the

number of new cases being diagnosed annually has been rising for at least

40 years, particularly in youngsters under the age of five.

 

It is widely accepted that the cancer starts in the womb, with some second

event triggering development of the disease in childhood.

 

Scientists are now trying to find out whether genetic, environmental,

dietary or other factors are causing more children to be struck down.

 

Professor Michel Coleman, Professor of Epidemiology and Vital Statistics at

the London School of Hygiene and Tropical Medicine, said: “We have become

steadily better at treating it – at least in the sense of preventing

children dying from it – but we have made little or no progress in

preventing it.

 

“Rational approaches to prevention are difficult to formulate when so

little is known about the cause.”

 

In the late 1960s the mortality rate for leukaemia among children up to 14

was about 26 deaths per million of the population in England and Wales.

This dropped to around 10 per million by the late 1990s.

 

But the incidence rate increased from about 40 cases per million in the

1960s to 45 per million in the late 1990s.

 

However, by looking at reliable mortality trends between 1911 and the 1950s

and incidence and survival data available since the 1960s, Prof Coleman

said it was apparent that the rise in cases had been going on much longer.

 

“Suggestions that part of the increase has been due to more children

surviving infancy to reach the peak age of leukaemia incidence (1-4 years)

and to improved registration and diagnosis of the disease, may be partly

true, but they cannot plausibly explain the overall pattern of data now at

our disposal,” he said.

 

The charity Children with Leukaemia – which today launched a £1 million

fund for new research – said the upward trend in cases, the inability to

pin down the cause and concerns over the long-term effect of cancer

treatments had prompted it to organise the conference.

 

This week experts from across Europe, America, Asia and Australia will

discuss issues such as radiation, smoking, viruses and air pollution.

 

They will also look at areas which have received less attention, such as

the impact of diet in early childhood, light pollution, damaging materials

affecting the unborn child and medicines in pregnancy.

 

Conference chairman Professor Denis Henshaw said: “If the increased risk

facing today’s children is at least partly caused by modern lifestyle

factors, as is suggested by the increasing incidence, then it may be

possible to take some preventative measures.

 

“But first we need to determine what these factors are.”