Ahlbom sounded a similar theme. If we had supporting ex perimental data, he said, the epidemiology would have been strong enough for a causal interpretation quite some time ago. But without that, the requirements on epidemiological data be come rather strong. Both pooled analyses show that at higher levels of exposure, measured field levels are in fact linked to increased risks. It is unclear why previous wire-code studies found the opposite, they write, but there may have been considerable potential for bias.
Day takes an even stronger view.
He cited both the NCI data and the pooled analysis led by Ahlbom. If there is any relationship with mag netic fields, Day argued, it is not the one put forward on the basis of wire codes. He pointed out that the pooled analysis by Ahl born, Day and colleagues only included the two most negative of the wire-code studies. We felt that if we could also incorporate new studies from non-European countries, this pooled analysis would be up to date and presumably stay current for several years, the paper states. Ahlbom and colleagues analyzed raw data for 3,247 children with leukemia and 10,400 controls.