Researchers suggest playgroups could be linked to lower leukaemia risk

In collaboration with the Press Association

A new study suggests that children who attend playgroups may be less likely to develop the most common type of leukaemia. But a Cancer Research UK scientist said that a better understanding of the phenomenon was needed before advice could be given to parents.

Researchers at the University of California, Berkeley, analysed 14 published studies which had looked at the link between playgroup attendance and acute lymphoblastic leukaemia (ALL), which accounts for more than 80 per cent of cases of the disease.

The combined studies contained data on 6,108 children with leukaemia and a further 13,704 who were cancer-free, including information on their day care and playgroup attendance.

Twelve of the 14 studies found evidence that interaction with other children provides some protection against leukaemia, while two found no effect.

The study lends weight to the theory that children having regular contact with other children leads to them developing minor infections, which in turn affects the immune system in a way that makes leukaemia less likely.

Lead researcher Dr Patricia Buffler, professor of epidemiology at the School of Public Health of the University of California, Berkeley, said: "Combining the results from these studies together provided us with more confidence that the protective effect is real. Analysing the evidence in this way gives a more reliable answer to the question and a more precise estimate of the magnitude of the effect.

"Our analysis concluded that children who attended day care or play groups had about a 30 per cent lower risk of developing leukaemia than those who did not. Combined results for studies of day care attendance specifically before the age of one or two showed a similarly reduced risk," she revealed.

The findings were presented at the Children with Leukaemia Causes and Prevention of Childhood Leukaemia Conference in London on April 29th.

Professor Jillian Birch, director of Cancer Research UK's Paediatric and Familial Cancer Research Group at the University of Manchester, revealed that childhood cancers are rare, affecting around one in 500 children before the age of 15.

"Many studies have found evidence for a link between infection and childhood leukaemia, but exactly how infection affects a child's risk of developing the disease still remains unclear," she said.

"Until we have conclusive evidence on the risk factors for childhood leukaemia and an understanding of a mechanism behind its link with infection, it's too early to make recommendations on how to avoid this relatively rare disease."