Arsenic in Rice: Another Bloody Election

Toxic Endpoint Election

The basic idea of the risk assessment paradigm is that it has two steps (NRC, 1983).  In the first step, the risk assessors produce the best information they can about a particular hazard that they have identified.  In the second step, the risk managers take that information and do their best to manage the risk for the benefit of the public.  But the risk assessment paradigm has an evil twin.  The risk propaganda paradigm begins with identification of an issue that the managers would like to be in control of for the benefit of themselves and their friends.  The initial process is followed by a risk caressment process, where the analysts produce a result that justifies a decision that has already been made.  Perhaps the most well-known example of the risk propaganda paradigm is the GW Bush White House using weapons of mass destruction (WMD) as a pretext for the invasion of Iraq. 

Unlike the apple juice risk assessment, the FDA (2016a) risk assessment for arsenic in rice contains a section on noncancer endpoints.  The National Institute on Environmental Health Sciences (NIEHS) has been funding many “low-dose” epidemiology studies over the last 15 years, there are many new reports in the literature of associations between arsenic and many different toxic endpoints.  However, since there has been an emphasis on studies on women’s and children’s health, that is what most of the resulting publications have been concerned with.  The problem is that the modus operandi in epidemiology these days is to conduct a post-hoc analysis that yields a statistically significant result, write a paper, and then call up the university press office to report the association to the public.  But it’s not an association or statistical significance that matters, it’s causality.  And most environmental epidemiology studies these days don’t seem to be designed or analyzed with the goal of demonstrating causality.

Fortunately, the National Academy of Sciences (2013) recently reviewed the literature on arsenic and sorted the various potential endpoints into “tiers” that grouped them based on the strength or weight of the evidence for a causal relationship.  The noncancer endpoint that fell into the top tier was cardiovascular disease.  The reason for that is pretty simple; while there are multiple studies showing a dose-response relationship between inorganic arsenic and cardiovascular disease, there is little to be found beyond statistical significance for the other endpoints.  So, if you want a quantitative assessment for a noncancer endpoint, cardiovascular disease is pretty much the only choice.

But, that’s not what the FDA did.  They skipped over cardiovascular disease and went for the Tier 2 and Tier 3 endpoints associated with pregnancy and childhood development.  The fact that there were no data to support a quantitative assessment was found to be lamentable, but it left them undeterred.  That might seem unfathomable, but once you understand that it’s the risk propaganda paradigm at work, some reasons for it aren’t that hard to come up with: a) NIEHS wants to justify funding studies that aren’t really very useful, b) the Society of Toxicology wants to create jobs for women who understand pregnancy and children so much better than men do, c) issues concerned with environmental effects on pregnant women and children are part of the Democratic party platform, and d) all of the above.  I think d is the correct answer, but it's mostly a.

Risk Manglement

In its purest form, the risk propaganda paradigm isn’t used very often.  That is because it often ends up with lies that are obviously not true.  Propaganda works much better when it is at least partially true.  The WMD ruse is a pretty good example.  Iraq was invaded, but as it turned out, the WMDs just weren’t there.  The noncancer risk assessment for arsenic in rice is like that too.  The table of contents suggests that there is a risk assessment, but if you look inside it’s just not there.  No quantitative risk assessment, no safety assessment, just an exposure assessment.

Yet the guidance issued by the FDA (2016b) relies primarily on the noncancer nonassessment anyway.  Perhaps that is because the quantitative assessment indicates that, as with apple juice and as usual, setting levels are not a very effective way to reduce the risk from naturally occurring contaminants.  If your management strategy isn’t going to work, then maybe it is better to use a nonassessment that doesn’t show anything at all.  But, the cancer assessment really is a better justification.  The evidence for an effect is stronger, there is some basis for quantifying how big the effect might be, and there is substantial evidence that exposure earlier in life is more important.  The FDA survey indicated that levels of arsenic in infant cereal are actually higher than rice in general, and there is no good reason for that.  A “37 percent reduction in lifetime cancer risk attributable to brown-rice infant cereal consumption” isn’t much, but it’s something.

In addition to proving a guidance level for inorganic arsenic in infant cereal, the FDA (2016c) also suggests that infants and pregnant women should modify their rice consumption.  Again, the cancer risk assessment is arguably sufficient justification for not using rice cereal as the major staple for infants.  But, the advice to pregnant women rests solely on the dubious and unquantifiable Tier 2 and Tier 3 effects.  The review quoted by the FDA as justification for that focus also lists cadmium, copper, iron, manganese, and zinc as potential concerns in addition to arsenic (Wright and Bocarelli, 2007).  What about them?  If simply declaring a causal relationship without any consideration of the relationship between dose and health outcome is sufficient for consumer advice, then what are pregnant women supposed to eat?  Acrylamide – well there goes the bread.  Water is out too – hyponatremia can cause severe brain damage.  Perhaps they can still eat cake.

But, never mind the infants and pregnant women, what about the rest of us?  The guidance document says that

The FDA did not find a scientific or public health basis to recommend that the general population of consumers change its rice consumption based on the presence of arsenic.

What the hell happened to the Tier 1 effects?  Lifetime exposure to arsenic is still causing lung and bladder cancer, right?  What about those cardiovascular effects that the FDA skipped over?  What about the fact that adult males are exposed to about twice as much arsenic from rice products (it’s beer) as adult females?  How come we don’t get advice too?  I’m going to drink the beer anyway, but still I’d like to feel needed.

I’d just blame the Center for Food Safety and Applied Nutrition for being so stupid, but I also know that they bear only proximal responsibility for this gross insult to the intelligence of every woman, man, and child in the United States.  I figure NIEHS, the rest of HHS, the EPA, the Society of Toxicology, the Democratic party, and the bankers who supplied campaign funds for a voting bloc also helped set the propaganda campaign in motion. 

References

National Research Council (1983).  Risk Assessment in the Federal Government: Managing the Process. National Academy Press, Washington, DC.

National Research Council (2013). Critical aspects of EPA’s IRIS assessment of inorganic arsenic: interim report.

U.S. Food and Drug Administration (2016a).  Arsenic in Rice and Rice Products Risk Assessment.

U.S. Food and Drug Administration (2016b).  Supporting Document for Draft Guidance for Industry on Inorganic Arsenic in Rice Cereals for Infants: Action Level.

U.S. Food and Drug Administration (2016c).  For Consumers: Seven Things Pregnant Women and Parents Need to Know About Arsenic in Rice and Rice Cereal.

Wright, RO and Baccarelli A. (2007). Metals and neurotoxicology. The Journal of Nutrition 137: 2809–2813.

Official Post Soundtrack

Killing Joke (1996).  Another Bloody Election.  In Democracy, Track 10.

Post Notes

Thesis Post #61 and part two of two on the FDA Arsenic in Rice Risk Assessment.  You may notice that in the previous post I refer to my former agency as "we", but as "them" in this one.  That's because the agency I used to belong to doesn't exist anymore.