News in Science

Dads' exposure to solvents linked to childhood brain tumours

Solvent risk Brain tumours in children could have as much to do with the father's occupational exposure to solvents as they have to do with the mother's, a new Australian study has found.

The study, published in the British Journal of Cancer, has found a link between parents' exposure to chemicals such as benzene, toluene, and trichloroethylene and brain tumours in their children.

Lead author Dr Susan Peters, occupational epidemiologist at the University of Western Australia, says while brain tumours are relatively rare they are a major cause of cancer death among children, and the causes are largely unknown.

"Because most of the cases occur before age five, the question is what are the risk factors because there are some genetic syndromes that are known to cause brain tumours but only in less than five per cent of cases," says Peters.

"The children are pretty young, [so] it could be that some of the parental exposures before or during pregnancy may be a cause."

The new study surveyed nearly 306 cases of parents of children up to 14 years old with brain tumours, which were diagnosed between 2005 - 2010 in Australia.

The researchers compared the parents' occupational exposures to solvents with those of 950 parents whose children did not have brain tumours.

The findings suggest that fathers working in jobs where they are regularly exposed to benzene in the year before their child is conceived are more than twice as likely to have that child develop a brain tumour.

Women working in occupations that expose them to a class of compounds called chlorinated solvents -- found in degreasers, cleaning solutions, paint thinners, pesticides and resins -- at any time in their lives also have a much higher risk of their child developing a brain tumour.

Building on previous studies

While brain tumours in children are relatively rare, previous studies have suggested a link between parental occupation and childhood brain tumours, finding parents working in industries such as the chemical and petroleum industries, car-related jobs, and jobs with regular exposure to paint, have a higher risk of their children developing brain tumours.

Peters says a previous study in rats also found that toluene -- found in petrol, paints, and inks -- had an effect on sperm cells, which points to a possible explanation for the link in humans.

Commenting on the study, Emeritus Professor Michael R. Moore, vice president of the Australasian College of Toxicology and Risk Assessment, says the data shows paternal exposure was a key issue.

"This is the children being directly affected by the father and the father's exposure is taking place prior to the children being conceived," says Moore.

"Parents who are thinking of having children should be thinking about not just what's happening with the mums but also with the dads."

Peters stressed that the study only involved relatively small numbers of cases, and it was still too early to say whether solvent exposure was the cause of childhood brain tumours.

However she said these solvents were associated with a range of other effects so exposure should be kept as low as possible anyway.