Tuesday, April 26, 2011

Herald Column: In Search of Evidence-Based Policy

My latest Calgary Herald column looks at some recently published studies and how they contrast with government policy:
 
...In recent days, we’ve seen new evidence emerge further confirming our lamentable trajectory away from evidence-based policy.
The question of Vancouver’s safe injection site, better known as Insite, is one example. A court ruling next month will help decide whether Insite continues to operate under an exemption to federal drug laws – an exemption the Conservatives seem intent on ending.
The evidence tells us quite overwhelmingly, though, that Insite’s approach works. The latest study, published in the The Lancet, shows the fatal overdose rate near the Insite facility fell by 35 per cent over the first 27 months of its operation, whereas the rate dropped by just nine per cent over the rest of the city.
Even more remarkably, though, for women and aboriginals, the rate drop near Insite was 50 per cent, whereas the rate for those two groups actually doubled in the rest of Vancouver.
The case against Insite seems primarily ideological, but it’s not always ideology that leads us astray. In fact, it can often be a well-meaning desire to “protect” people. Not that there’s anything wrong with keeping people safe, but we need evidence to determine what those dangers are. Often the precautionary principle is taken too far.
That appears to be the case with Bisphenol-A (BPA). Canada took the lead in banning the chemical from baby bottles, and recently BPA was added to Canada’s official list of toxic substances.
Last year, however, an international panel of experts convened by the World Health Organization concluded that the evidence for BPA's alleged health risks is weak, and that a ban is premature. A study published this month in the journal Critical Reviews in Toxicology concurs.
It found that current tolerable daily intake levels for BPA are sufficient and that most people come nowhere near those limits. The study concludes that “available evidence indicates that BPA exposure represents no noteworthy risk to the health of the human population, including newborns and babies”.
So did Canada overreact? So it would seem. And yet, no politicians have called attention to this.
Another area where a well-meaning effort to help people appears at odds with the scientific evidence is the so-called “Liberation Treatment” for multiple sclerosis (MS) based on Italian researcher Paolo Zamboni’s theory that the disease is caused by vein blockages, dubbed CCSVI.
Many Canadian politicians have taken an unusually active interest in this. Alberta committed $1-million to a study of the procedure, and other provinces promised funding for clinical trials – despite the Canadian Institutes for Health Research (CIHR) warning against doing so. The federal Liberals even criticized the Conservatives for following the CIHR’s advice.
However, many subsequent studies have found no correlation between these blockages and MS. So far no one has replicated Zamboni’s findings.
A large study this month out of the University of Buffalo found CCSVI in 56 per cent of MS patients, and 42 per cent among those with other neurological condition. It was also present in 23 per cent of healthy patients. The authors suggest that MS might be causing CCSVI, but conclude the reverse is unlikely.
More research is needed, but so far the scientific evidence is not matching the enthusiasm of many policy makers. While the door should not yet be closed on this theory, we should consider the risks of devoting great amounts of resources into a theory that might not pan out.
Many hopes were raised by Zamboni’s theory, but wanting it to be true does not make it so. As disappointing as it may be, we need to heed the evidence.
As we’ve seen, though, when the evidence clashes with our hopes, our fears, or our long held beliefs, it can be easy to ignore.
That’s no excuse for policy makers and politicians. An improvement on the status quo is not too much to ask. 

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