Childhood cancers linked to pollution, claims study

[Guest guest]

http://news.scotsman.com/health.cfm?id=1761712005

Childhood cancers linked to pollution, claims study

LOUISE GRAY

CHILDHOOD cancers are strongly linked to engine

exhausts from cars and factories, it was claimed

yesterday.

Scientists made the link by linking pollution

" hotspots " on a map of Britain to a higher risk of

childhood cancer.

Knox, emeritus professor at Birmingham

University, looked at maps published by the National

Atmospheric Emissions Inventory (NAEI) of pollution

levels across the country in 2001.

He also looked at the position of particular emission

sources such as hospitals, bus and train stations,

heavy transport hubs and oil installations.

Chemical emission included carbon monoxide,

particulate matter, nitrogen oxides, 1,3-butadiene,

benzene and volatile organic compounds.

Prof Knox then looked at the postal addresses of

22,500 children who died of cancer in Britain between

1955 and 1980. To calculate the risk of cancer near

particular hotspots, he looked at where the children

who later died of cancer were born.

The study in the Journal of Epidemiology and Community

Health found there was excess risk for children living

within 0.3km of a chemical emission hotspot.

In a breakdown of emissions, 1,3-butadiene and carbon

monoxide - both of which are produced by vehicle

exhausts, and particularly diesel engines - were among

the primary culprits, the study suggested.

Prof Knox said: " Within a short range of installations

that emit these chemicals, that is within 300 metres,

the risk is at least doubled and in some cases more

than doubled. Not enough to worry the individual, but

enough from a public health point of view. "

Proximity of up to a kilometre of an emissions

hotspot, such as a transport hub, also increased risk.

The combination of proximity to an emissions source in

a pollution hotspot increased the child's risk by up

to 12 times, the study said.

Prof Knox said his study showed a need for a

realisation of the risk of pollutants in public

health.

He said he accepted that atmospheric safety levels for

1,3-butadiene should be lowered so as not to harm the

health of children in the womb and soon after birth -

when they are most at risk.

He also said all vehicles should be fitted with

catalytic converters, including lorries and public

transport like buses and trains should have stricter

guidelines to avoid leaving the engine running

unnecessarily.

Prof Knox said parents should not be worried as the

risk of childhood cancer is so low - one in 800 - that

the relative increase would not necessarily mean a

very high risk.

But he defended his study.

" People ask: Do you think you are worrying people? But

I think there is less worrying in knowing where the

disease comes from. "

However, Freda , emeritus professor of cancer

epidemiology at the University of Edinburgh, said the

study was not convincing.

She said the study did not have a control group of

healthy children to compare the birth and death rates

to and said no account was taken of factors other than

pollutants, such as social status.

Prof said the study was " interesting " but

more research was needed.

Recent research includes a theory that children who

develop cancer have a fairly common chromosome defect

that occurs in the womb. Then at some point later in

life, something else happens to trigger the cancer.

Prof continued: " The sad thing is we do not

know what causes childhood cancer. The study is right

that cancer takes hold very early in life but we do

not know what causes this. "

Ken of the Leukaemia Research Fund was also

unconvinced.

He pointed out that the map used by Prof Knox shows

the emissions from 2001. But the cancer deaths

compared to the map are over a period from 1955 to

1980.

He also said the map used by Prof Knox did not give an

accurate picture of which addresses are close to

pollutants because they are broken down into such

large areas.

Mr said the recent UK Childhood Cancer Study

had ruled out pollutants as a cause. It also ruled out

links with power lines, breast feeding, parental

smoking and background radiation as possible causes of

the disease.

He said: " A recent high-quality study has found no

evidence to support this hypothesis. And we would be

concerned there is a very large mismatch between the

time of the data and the time of deaths of the

children. Also, it is our understanding from NAEI that

the scale of the maps would not permit extraction of

data at this level. "