IN SEPTEMBER last year, the first International Expert Conference on Cell Phones and Health was convened in Washington.

Though there was little media coverage of the event, the United States Senate took advantage of the presence of experts in town to hold a hearing on the issue. This was all the more timely since most of the scientists on the issue hailed from Europe and had taken part in a 13-country, decade-long study nn the issue.

The US, however, was not one of the 13 countries involved in the study, called Interphone. Though conducted under the auspices of the World Health Organisation (WHO), Interphone was largely funded by the cellphone industry. Thus, with its much awaited report still unpublished, people had already become very suspicious of the study.

Nevertheless, we are not without access to some of the results of the study as the scientists involved have published some of their findings ill peer-reviewed journals.

Whenever a scientific paper is published by these scientists linking cell phone usage to health problems - most importantly, to an increased incidence of brain cancers - industry spinmeisters can be expected to be out in force. There have been reports of scientists who establish a link between cellphone usage and cancers finding their funding drying up.

There are, to date, 632 papers on this issue that have been published in good scientific journals. Only half of these papers claim a link. About a dozen design flaws can be identified in these studies. But the impact of these flaws, methodologically speaking, is to underestimate, not overestimate, the health link.

One of the most important methodological flaws is that cellphone usage is always estimated through user recall, which industry says is subject to recall bials. Yet the industry has precise usage data for each cellphone user but refuses to release such data for scientific study, allegedly because of privacy concerns.

There are also some scientists who refuse to accept the body of evidence regarding the health risks as they are mostly epidemiological in nature. That is, the evidence comes from identifying heavy cellphone users and also finding brain tumours among many such users.

Noting that this is just a correlation, which is not necessarily causal, such scientists would like to see more robust evidence. What they would see as evidence of causation is identifying the actual biological mechanisms involved.

The fundamental science issue is this: How does the radiofrcquency radiation from cellphones cause DNA damage (or gene mutations) which may then lead to cancer? Much work remains to be done in this area.

But should we wait to have such evidence in hand before we limit our cellphone usage and, more critically, that of our young?

Industry safety standards for cellphone use are predicated on a very large adult with a very large head and very thick skull bones. However, children are nowadays starting to use cellphones from a very young age when their brains are still maturing (a process which continues until about age 20) and their skull bones are relatively thin.

Moreover, brain tumours are known to take decades to develop. But widespread heavy cellphone usage begun only from the mid-1990s, and that only in some countries like Sweden and Japan. Following their usual biological behaviour, we should expect an epidemic of brain tumours as a result of widespread cellphone usage worldwide, if it occurs, only from the 2030s. By then, it might be too late tor you - or your child.

How then should we proceed with the largely epidemiological evidence linking celbhone use to brain cancers? A comparison with the history of smoking and the time trends of lung cancer in the US may be instructive.

The rise in per capita smoking in the US began in the earlier part of the 20th century. But it took 10 to 15 years before the epidemic of lung cancer among male smokers was observed. Evidence of an epidemic in female smokers would take an other 20 years to manifest itself, for women took to smoking later.

At the time these correlations were first noted, the biological mechanisms by which tobacco smoke caused cancer were still unknown. Yet, even in 1950, there were already five important studies show ing that long-term male smokers were nine times more likely than non-smokers to develop lung cancer. Meanwhile, the tobacco companies already had their public relalions consullants spinning the bail news too.

Since brain tumours take so long to develop - meningiomas and acoustic aromas take 20-40 years to grow and become detectable, for instance - and unless cellphones are more potent at initiating and/or promoting brain cancers than tobacco is with regard to lung cancer, we should not expect to see very strong epidemiologicai evidence of the link, if any, yet at this time. This could well be the reason for the conflicting cellphone studies.

Tlie red flags, however, might well suggest lhat we are, right now, at the leading edge of a serious epidemic of brain cancers. If so, it might be high time for Singapore to insist - just as Israel has done for the past few years - that cellphone sellers display prominently and without fudging how much radiation their models emit.

Singapore could also emulate those European nations that have already issued advisories - especially to children - to speak less on their cellphones. Use the speakerphone if you do. Better yet, just send an SMS instead. If possible at all, switch your cellphone off instead of keeping it turned on and placed against your body in that pocket.

You have been duly warned.