Sunday, May 13, 2007

Some people read spicy novels. Molly reads CDC reports. They can be sexy in their own weird way. One of the latest that she has read is 'State-Specific Trends in Chronic Kidney Failure- United States 1990-2001'. Now I don't want to make too much out of this, as the trends presented in this report are far from "definite" as to a "new cause". What they do show, however, is that the incidence of chronic renal failure in the USA increased 104% from 1990 to 2001, from 697 to 1,424 cases per million population. The "causes" of this are divided between 1)hypertension, 2)diabetes and 3)other causes. The increase was put down to a 99% increase due to hypertension, a 194% increase due to diabetes and a 64% increase due to "other causes". Looking over the data for individual states the case of Arkansas stands out as an anomaly with an increase of 1,206% due to "other causes". This is probably an anomaly due to reporting procedures as the 1990 reportage of "other causes" was abnormally low as compared to other states.
But what was the nature of the reporting anomaly ? Stop and think for a minute. Is it possible that once either hypertension or diabetes is part of the history or presentation of a patient with renal failure that all investigation stops there and then ? It is a sufficient cause ? But is it the only cause ? How much of the rise in renal failure in US patients is due to causes that are just not investigated once a presumed pathological diagnosis is made ? Is it possible that some people may be particularly sensitive to low levels of melamine because they are already marginal in renal function ?
Molly is fully aware that the animal deaths that have occurred recently are acute rather than chronic, but they have occurred in particularly sensitive species such as the cat. If one billion crystals can destroy entire kidneys rapidly it is conceivable that 1,000 crystals (below detectable limits) can slowly destroy kidneys in less susceptible species a few nephrons at a time.
Once more Molly doesn't claim that this is definite. All that she says is that it is the sort of suggestive evidence that public health agencies should be investigating rather than making reassuring statements.

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