A planned Dunedin study into whether fluoridated water
reduces IQ has been shelved.
However, another University of Otago study looking at the
same controversial question has been completed, its findings
accepted for publication later this year in a prominent
American public health journal.
Co-authored by public health dentistry specialist Dr Jonathan
Broadbent, it found no negative effect on IQ.
Leader of the shelved study, child health researcher Prof
Barry Taylor, said in an email the required data was too
difficult to obtain.
''The fluoride data from the Ministry [of Health] has not
[been] easy to interpret and match to the B4 School data - it
has got to the stage where I do not think it is worth more
effort at present.''
Prof Taylor had hoped to use information obtained from health
and development checks performed on children before they
start school, known as a B4 School Check.
Dr Broadbent's study drew on the Dunedin Multidisciplinary
Health and Development Study, whose director, Prof Richie
Poulton, worked alongside Dr Broadbent and other academics on
the IQ study.
The ''world class'' Dunedin study was better suited for the
analysis than before-school checks, he believed.
Overseas studies cited by anti-fluoride campaigners showing
reduced IQ were ''rubbish'' because of design flaws, and had
been widely discredited, he said.
The Dunedin study data was used in research that revealed
marijuana adversely affected IQ. He believed some
anti-fluoride campaigners supported decriminalising cannabis,
which he found ''intriguing'' given its effects on the brain.
Visiting anti-fluoride campaigner Emeritus Prof Paul Connett,
of New York, said independent scientists were concerned about
the harm caused by fluoride.
That one study found no effects did not outweigh 37 overseas
studies that demonstrated adverse effects, he said when
contacted near Wellington.
He would examine them upon publication, but Dr Broadbent's
study findings sounded ''rather convenient'', Prof Connett
A moratorium should be introduced to halt fluoridation of
water supplies until the science was settled, he said.