Warning: Using a mobile phone while pregnant can seriously damage your baby
Study of 13,000 children exposes link between use of handsets and later behavioural problems
Sunday, 18 May 2008
A giant study, which surveyed more than 13,000 children, found that using the handsets just two or three times a day was enough to raise the risk of their babies developing hyperactivity and difficulties with conduct, emotions and relationships by the time they reached school age. And it adds that the likelihood is even greater if the children themselves used the phones before the age of seven.
The results of the study, the first of its kind, have taken the top scientists who conducted it by surprise. But they follow warnings against both pregnant women and children using mobiles by the official Russian radiation watchdog body, which believes that the peril they pose "is not much lower than the risk to children's health from tobacco or alcohol".
The research at the universities of California, Los Angeles (UCLA) and Aarhus, Denmark is to be published in the July issue of the journal Epidemiology and will carry particular weight because one of its authors has been sceptical that mobile phones pose a risk to health.
UCLA's Professor Leeka Kheifets who serves on a key committee of the International Commission on Non-Ionizing Radiation Protection, the body that sets the guidelines for exposure to mobile phones wrote three and a half years ago that the results of studies on people who used them "to date give no consistent evidence of a causal relationship between exposure to radiofrequency fields and any adverse health effect".
The scientists questioned the mothers of 13,159 children born in Denmark in the late 1990s about their use of the phones in pregnancy, and their children's use of them and behaviour up to the age of seven. As they gave birth before mobiles became universal, about half of the mothers had used them infrequently or not at all, enabling comparisons to be made.
They found that mothers who did use the handsets were 54 per cent more likely to have children with behavioural problems and that the likelihood increased with the amount of potential exposure to the radiation. And when the children also later used the phones they were, overall, 80 per cent more likely to suffer from difficulties with behaviour. They were 25 per cent more at risk from emotional problems, 34 per cent more likely to suffer from difficulties relating to their peers, 35 per cent more likely to be hyperactive, and 49 per cent more prone to problems with conduct.
The scientists say that the results were "unexpected", and that they knew of no biological mechanisms that could cause them. But when they tried to explain them by accounting for other possible causes such as smoking during pregnancy, family psychiatric history or socio-economic status they found that, far from disappearing, the association with mobile phone use got even stronger.
They add that there might be other possible explanations that they did not examine such as that mothers who used the phones frequently might pay less attention to their children and stress that the results "should be interpreted with caution" and checked by further studies. But they conclude that "if they are real they would have major public health implications".
Professor Sam Milham, of the blue-chip Mount Sinai School of Medicine in New York, and the University of Washington School of Public Health one of the pioneers of research in the field said last week that he had no doubt that the results were real. He pointed out that recent Canadian research on pregnant rats exposed to similar radiation had found structural changes in their offspring's brains.
The Russian National Committee on Non-Ionizing Radiation Protection says that use of the phones by both pregnant women and children should be "limited". It concludes that children who talk on the handsets are likely to suffer from "disruption of memory, decline of attention, diminishing learning and cognitive abilities, increased irritability" in the short term, and that longer-term hazards include "depressive syndrome" and "degeneration of the nervous structures of the brain".
A small molecule may have a big role in making the body clock tick, say Cambridge University researchers.
Studies in mice have shown cAMP - a common signaling molecule - is involved in keeping the body clock "rhythms" going.
The team hope to develop drugs that target cAMP to help shift workers, frequent flyers or those with sleep disorders reset their body clocks.
But the research, published in Science, is still a long way from the clinic.
The body's internal clock is a highly sensitive mechanism able to anticipate changes in the environment and regulate a host of body functions, from sleep patterns to metabolism and behaviour.
Disruption of these "circadian" rhythms have been shown to be linked with insomnia, depression, heart disease, cancer and neurodegenerative disorders.
|What's neat about cAMP is that it is very easily controlled by different medicines and compounds |
Dr Michael Hastings, study leader
At the beginning of the circadian day, genes are switched on which then produce proteins which in turn go on to switch off the same genes at the end of the day.
The proteins are broken down over the circadian night and the process starts all over again in the morning.
Researchers at the Medical Research Council Laboratory of Molecular Biology discovered that cAMP not only helps regulate the production of these proteins but that its own rhythm is also regulated by this "loop".
In laboratory experiments in cells the proteins were engineered to light up so the researchers could easily monitor the circadian rhythms depending on how much protein was present dependent on the activity of cAMP.
Study leader Dr Michael Hastings said in mice who by a quirk of genetics had a 20-hr body clock, they were able to reset the clock to 24 hours by using known compounds that are known to slow down the action of cAMP.
"What's neat about cAMP is that it is very easily controlled by different medicines and compounds."
He added the MRC had filed a patent for developing ways to manipulate cAMP with regards to body clock but there were 15 to 20 years of experiments before any drug would be available for human use.
"If you're flying to California it takes eight to nine hours and the body clock can adjust by one hour for each day so it takes about a week and then you have to come back.
"What we need to do is slow down the clock for that first day from 24 to 36 hours so you would already be in sync with California time," he said.
Dr Neil Stanley, a sleep expert at Norwich University Hospital, said the body clock was an incredibly complex system.
"This is very interesting from a biological basis but the perils and pitfalls of trying to develop new methods for regulation of sleep are great.
"For example melatonin hasn't really fulfilled its promise and it's been harder to use it usefully than people once hoped."