Scientists have uncovered evidence suggesting childhood brain cancer may be linked to measles or flu infection around the time of birth.

Children in areas where cases of measles were common around the time they were born were at twice the normal risk of developing brain tumours, according to the study.

Avoiding these infections might be one way of reducing cancer rates

Professor Louise Parker

Exposure to the flu virus appeared to triple children's risk.

In March, Cancer Research UK scientists reported the first evidence that childhood brain cancers might be caused by infection.

The new study - which researchers stress is only preliminary - is the first to suggest the specific infections that may be involved.

Birth records

Scientists in Newcastle examined all birth records in Cumbria from 1975 to 1992 - amounting to a total of 100,000 - and recorded in which of the county's six districts the births took place.

For each district they assessed exposure levels to a number of infections, including measles and flu, by counting the number of cases and deaths that occurred each month.

The scientists estimated exposure levels before birth, in the three months around and immediately after birth and in the subsequent period of three months.

They then attempted to relate levels of infection to the risk of developing brain tumours later on in life.

The risk of developing brain cancer before the age of 14 was more than doubled with high exposure to measles around the time of birth and more than tripled with exposure to the flu virus over the same period, the study found.

Exposure to measles or flu at other times, and exposure to other kinds of infection, seemed to have no effect on cancer rates.

Caution

The results should be viewed with caution as they are based on a very small number of cases

Professor Jillian Birch

Lead researcher Professor Louise Parker, at the University of Newcastle's North of England Cancer Research Unit, said: "There's increasing interest in the possibility that exposure to infections very early on in life might contribute to the incidence of children's brain cancer and our study is certainly consistent with that possibility.

"It's difficult to produce strong evidence on the causes of childhood brain cancer because the disease is rare and even when you look at large numbers of children, in our case 100,000, the number of cancers will be quite small.

"But our results do suggest that measles and flu could be associated with increased risk of the disease, and therefore that avoiding these infections might be one way of reducing cancer rates."

Professor Jillian Birch, director of the Cancer Research UK's Paediatric and Familial Cancer Research Group in Manchester, said the results seemed to back the theory that some childhood brain tumours were linked to infection.

However, she said: "The results should be viewed with caution as they are based on a very small number of cases.

"Further work is needed to see whether similar findings can be demonstrated in an independent set of data."

Childhood brain cancer is a rare disease, affecting around 290 children each year and causing about 100 deaths.

The research is published in the British Journal of Cancer.