Head lice shampoo 'linked to leukaemia'
08:35am 17th January 2006
Using chemical shampoos to get rid of head lice could almost double the risk of children developing leukaemia, scientists have claimed.
Exposure to other insecticides while in the womb or as a child could also double the risk of contracting the cancer, they said.
The findings will fuel concerns about the increasing incidence of childhood leukaemia in Britain. Around 500 youngsters under 15 are diagnosed with the illness each year.
It kills more children than any other disease in the UK and cases among under-fives have risen by more than 50 per cent in 40 years.
The study, by the French research group INSERM, looked at 280 children newly diagnosed with acute leukaemia and a further 288 children matched for sex and age who did not have the disease.
The mothers of the children, who came from four French cities, were interviewed about their use of insecticidal head lice shampoos and of pesticides and fungicides in the home and garden. They were also asked whether they used the chemicals during and after pregnancy.
Based on what the mothers said, scientists concluded that using insecticidal shampoos could almost double the risk of developing leukaemia.
They also found the risk of developing acute leukaemia was almost twice as likely in children whose mothers said they had used insecticides in the home while pregnant and long after birth.
Dr Florence Menegaux, who led the study which is published in the journal Occupational and Environmental Medicine, said: "The findings reinforce the hypothesis that household pesticides may play a role in the origin of childhood acute leukaemia.
"At this stage no specific product can be singled out and a causal link remains questionable. However, the consistency of our results and the results from previous studies suggest that it may be opportune to consider preventative action."
The research did not specify any of the lice shampoo brands used by the children, but cited ingredients such as malathion, pyrethroid and lindane which are often in such products.
The most popular products available over the counter include Lyclear (containing permethrin - a pyrethroid) and Derbac-M, (containing malathion).
The UK market for head lice products is worth £15.6million per year. Special 'bug busting' combs and organic treatments are also used.
The Leukaemia Research Fund said: "This is a very small study and the evidence is very weak.
"However this does not mean there are no harmful consequences. More research is needed."
The Medicines and Healthcare products Regulatory Agency, the Government's drug safety watchdog, said: "We have tested the safety of current head lice lotions and shampoos available. Tests show that absorption into the body is quite minimal and we would not advise people to stop using them."
A spokesman for Chefaro UK, which manufactures Lyclear, said: "The statistical probability of there being a link appears to be very low. Lyclear Creme Rinse has been tested for toxicity, and absorption rates through the skin were found to be negligible."