Cellphones, cancer not tied

WASHINGTON – The first-ever study comparing brain cancer incidence in kids who use cellphones with those who do not has found no difference, suggesting that children’s long-feared vulnerability to brain cancer with early cellphone use does not exist.

In a four-country study published this week in the Journal of the National Cancer Institute, researchers matched 352 children and adolescents diagnosed with brain cancer with 646 similar kids who were healthy, and compared their patterns of cellphone use. The children ranged in age from 7 to 19, and researchers asked how long they had been regular users of mobile phones, which ear they tended to favor, and whether they ever used a hands-free device.

Some 55 percent of the children diagnosed with a brain tumor reported they had been regular users of a mobile phone before diagnosis. A slightly smaller 51 percent of the healthy children in the comparison group said they talked regularly on a cellphone. After grouping the children according to the intensity of the cellphone use, the researchers found no relationship between how often a child used a cellphone and the likelihood of his or her developing brain cancer. And brain tumors were no more likely to occur on the side that a child preferred to hold a cellphone to his head (where a cellphone’s heat, at least, might penetrate into brain tissue) than they were on the opposite side.

In the overall sample, children whose cellphone use had started earlier and continued for the longest time were not more likely to develop brain cancer. But in the small group of children for whom the researchers had cellphone-company records of a child’s earliest use, researchers did find a statistically significant increase in brain cancer risk for those who had their first cellphone earliest. While that may raise a flag, it’s not clearly red: Among kids who took up the habit earlier, a higher number of calls made on a child’s phone, or a larger accumulation of time spent on the phone, didn’t predict higher brain cancer rates.

“The available evidence does not support a causal association between the use of mobile phone and brain tumors,” the authors reported.

The findings of the study, conducted in Sweden, Norway, Denmark and Switzerland, are in line with those of a number of comprehensive studies completed, both in failing to find a strong causal link and in turning up a few worrisome exceptions. The Interphone Study, a 10-year, $14 million study that spanned 13 countries and released its findings in May 2010, failed to find a significant link between cellphone use and cancers of the brain, parotid gland or acoustic nerve. But it did find weak evidence that the heaviest cellphone users might be at increased risk for glioma – one type of brain cancer – and declared that further study was in order.