Question: When is no data all the data you need for a health scare? Answer: When the driving force is the insidious "precautionary principle."
The Food and Drug Administration warned us this week about plastic intravenous (IV) bags and tubes made with the chemical di-2ethylhexyl-phthalate (DEHP). Minute amounts of DEHP can leach from the vinyl into liquids.
Some researchers have reported testicle development and sperm production problems among some laboratory animals exposed to high levels of DEHP.
The FDA is advising hospitals to consider using devices made of different materials.
Hmmm … that must be the logical thing to do since, despite 40-plus years of use, the FDA has collected no reports of harm caused to humans by vinyl IV bags.
The FDA's stated rationale — if it can be called that — is, "We have not received reports of these adverse events in humans, but there have been no studies to rule them out."
More than four decades of real-life experience for naught because — get this — there’s a hypothetical possibility that vinyl IV bags may cause some unspecified harm in the future.
The IV-bag scare began in 1998 with headlines such as "Environmentalists allege cancer risks associated with plastic IV bags."
The "environmentalists" in question were led by Health Care Without Harm, a Greenpeace affiliate.
The cancer scare croaked two years later after a World Health Organization panel reviewed the science on DEHP and downgraded the chemical’s cancer classification from "possibly carcinogenic to humans" to "not classifiable as to carcinogenicity to humans."
The panel concluded that while larger doses of DEHP — much higher than anyone would ever be exposed to through IV bags — were associated with increased liver tumors in rodents, the biological mechanism by which DEHP produced those tumors doesn't exist in humans.
The panel decided the rodent data weren't relevant to humans.
But Health Care Without Harm refused to drop its scare. The anti-chemical activist group merely shifted gears saying, "Our concern has always been more focused on reproductive and developmental effects as well as the potential for kidney damage."
Health Scare Without Shame is more like it.
No one disputes that high doses of DEHP produce adverse effects in some lab animals. But that’s true for every substance.
A fundamental tenet of toxicology is, "the dose that makes the poison." Even water, sugar and table salt can be "toxic" if ingested in sufficient amounts.
The lowest levels at which rats and mice exhibit toxic effects from DEHP are still tens and hundreds of times higher than the highest human exposures from vinyl IV bags.
Even if high doses of DEHP contribute to reproductive problems in rats and mice, hamsters seem to be more resistant and monkeys are unaffected by DEHP. Decreased kidney function was reported in rats exposed to DEHP. But no loss of function has been reported in dogs or humans.
This probably explains why the FDA has no data linking vinyl IV bags with harm to humans.
The FDA justified its outrageous action through the "precautionary principle" — an extreme "better safe than sorry" line of reasoning that's been advocated for years by anti-chemical and anti-technology activists.
Most of us apply a reasonable form of the precautionary principle in everyday life. Riding in a car, for example, entails a real risk of getting into an accident. Through exercise of reasonable precaution, you may wear a seat belt to reduce the risk of injury should an accident occur.
The activists, however, apply an extreme form of the precautionary principle. They demand that, before being approved for use, chemicals and technology be proven absolutely safe under virtually all conditions into the future.
This equates to "proving a negative" — that something will never occur — a logical impossibility.
If the precautionary principle becomes the FDA's standard for approving medical devices — and food additives, pharmaceutical products and other items regulated by the agency — nothing will be approved for use.
At the very least, the precautionary principle provides the agency with the authority to engage in arbitrary decision-making.
My guess is that the FDA hasn't officially adopted the nutty precautionary principle — yet. Rather, the IV-bag controversy is below the Bush administration's radar and the dirty deed was done by some rogue, mid-level bureaucrat sympathetic to Health Care Without Harm.
The Bush administration needs to reconsider the IV-bag warning immediately to prevent needless panic among health care providers and the public and to prevent further use of the precautionary principle at the FDA.
Steven Milloy is the publisher of JunkScience.com, an adjunct scholar at the Cato Institute and the author of Junk Science Judo: Self-defense Against Health Scares and Scams (Cato Institute, 2001).