Friday, July 23, 2010

Inflated Claims of Antibiotic 'Over-use'

Political writer Gregg Easterbrook once remarked, "Torture the numbers long enough and they will eventually confess to anything." So is the case with the statistics thrown around regarding how U.S. farmers "over-use" antibiotics.

Although the FDA strictly regulates the type, form and dosage of antibiotics farmers can and cannot use in their animals, the reality is nobody knows exactly how much is eventually consumed at the farm and veterinary clinic. So the question is: Can your customers trust the numbers? A LITTLE PERSPECTIVE
The statistics most typically cited are based on interpretations and misinterpretations of a 2001 report called "Hogging It: Estimates of Antibiotic Abuse in Livestock." Commissioned by Boston's Union of Concerned Scientists (UCS), an advocacy group critical of numerous social issues including carbon emissions, SUVs, biotech and the war in Iraq, it claimed farmers use an "enormous" 24.6 million pounds of antibiotics yearly for “non-therapeutic” purposes, or 70 percent of all U.S. antibiotics. However:

  • The study's own authors concede there's no way to know which farms do and don’t use antibiotics, how long they use them, and which animals they choose to medicate. So they guessed. For cattle and hogs, they based their guess on a single USDA survey in each market which asked just a handful of questions about antibiotic use among dozens of others. Lacking a similar survey in poultry, UCS simply assumed all farms use them, based on a single-sentence opinion plucked from a 253-page National Research Council review of the issue. UCS then simply multiplied its guesses by the total number of animals and birds sent to market during the year.
  • To convert the 24.6 million pound guess into a percentage, the UCS authors likewise guessed at the total number of human prescriptions, based on — for inpatients — a National Center for Health Statistics survey and — for outpatients — the kind of market survey they dismiss as unreliable when done by animal-drug makers. They then estimated a "most likely" antibiotic poundage total by assuming what doctors ordered to fill those prescriptions. It "grossly underestimates the amount of hospital prescribing," according to Tamar Barlam, MD, former antibiotic resistance project director for the Center for Science in the Public Interest.
  • To support its belief antibiotics are "misused" and "nonessential," UCS invented a definition for "non-therapeutic" to count uses that keep animals from getting sick — a definition not supported by FDA. In the decade since the report, the phantom definition has suffered even further rendition creep, to the point it's now shorthanded to accounts like the Organic Trade Associations openly false accusation that "...70 percent of all antibiotics made in the United States are used to fatten up livestock."
  • The UCS report and those who use it employ some statistical sleight of hand to further inflate the implied risk that farm antibiotic consumption might be contributing to human drug failures. Not every type of antibiotic they stuff into their calculations is relevant to the resistance debate. Several antimicrobials — those known as ionophores, bambermycins, carbadox, tiamulin and organic arsenicals — are never used in humans. So, their use in farm animals poses no risk of causing human antimicrobials to fail. Subtract UCS's own estimates for how much of those antibimicrobials are used from the inflated statistics, and the oft-repeated 70 percent figure immediately falls to only 37 percent.
  • The 70 percent figure is obese with other paunchy inflations, including claiming poultry farmers use 1.8 million pounds of two antibiotics which poultry veterinarians agree are rarely if ever used, and counting nearly 22 tons of one antibiotic in pig farms that has never even been sold in the United States.


Blogger Pamela Vesilind said...

The author seems uncomfortable with the word “sub-therapeutic,” accusing UCS of inventing a descriptor for the practice of using antibiotics to “keep animals from getting sick.” Whether UCS was the organization to coin this term is immaterial. We can even call it something else – say, “Jerome.” In any respect, the only sound argument for having no term to describe this practice would be that the practice itself does not exist.

If the factory meat industries are not using antibiotics for preventative or prophylactic use en masse, then one would logically assume they would tell us so—and loudly! But they didn’t. The National Pork Producers’ Council came out fighting, attacking the FDA’s Guidance as lacking scientific basis (much as this post does), and asserting that the industry “need[s] every available tool to protect animal health.” The National Cattleman Beef Association’s response was guarded but similarly firm in its defense: “Preventative medicine is the cornerstone of maintaining a healthy U.S. cattle herd.”

The lack of denial should tell us that the FDA is appropriately turning its attention to this issue, whatever the exact statistics are. If the agency does not officially bless the term, it certainly seems to be recognizing the existence of the practice. This post reminds me of the adage that, if you don’t like the results, your best defense is to attack the study. This is subterfuge. I’ll leave it to the scientists at UCS to quibble with your portrayal of their statistical analysis as nothing more than mere guessing. However, the fact that the USDA has so little data about sub-therapeutic dosing—I mean Jerome—should concern us all.

Pamela Vesilind
Vermont Law School

7/30/2010 9:00 AM  
Blogger Anthony Schutz said...

This comment has been removed by the author.

8/03/2010 9:57 AM  

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