Handbook of Solvents - George Wypych - ChemTech - Ventech!

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Goyer, 48 who showed that existing renal diseases, particularly hypertensive and diabetic
nephropathies, are clear risk factors predisposing to abnormal accumulation and excess
blood levels of any nephrotoxic drugs and chemicals, as well as solvents. Indeed this observation
makes a lot of scientific and clinical sense, since it is known that the ability of the kidney
to excrete the breakdown metabolites of various materials including industrial solvents
is reduced with any incremental reduction of kidney function, and there would certainly be
more accumulation of these breakdown products, as well as the parental solvents in the kidney
tissue, and as such, it makes sense that these individuals with underlying kidney disease
such as hypertensive kidney disease, diabetic kidney disease, or interstitial kidney disease
which may not yet be clinically overt, are at a significantly increased risk of developing
chronic kidney disease as a result of the documented damaging effects of solvents on the
kidney.
20.4.5. EPIDEMIOLOGICAL ASSESSMENT
The epidemiological diagnostic criteria for most cases of end-stage kidney disease is deficient
since no etiologic information is available in the majority of the cases. Fewer than 10%
of the end-stage renal disease cases are characterized etiologically. 49 Clinically, many patients
are classified histologically such as glomerulonephritis, but little effort is made to
look for toxic factors. Indeed, the majority of the clinicians seeing patients with end-stage
kidney disease are not trained to look into occupational, environmental, or toxicological issues
and end-stage renal disease. Many patients are listed as having hypertensive end-stage
kidney disease and are presumed therefore to be “idiopathic” in origin, however, these cases
may very well be the result of other industrial and/or environmental factors, among them,
solvent exposure. Many of the problems in the epidemiological analysis is the result of a
great reserve capacity of the kidney that can function relatively adequately despite slowly
progressive damage. End-stage kidney disease is typically not diagnosed until considerable
kidney damage has already occurred at the time when the patient seeks clinical attention.
Furthermore, kidney biopsy and post-mortem examination, almost always find small kidneys,
inadequate to help in the histopathological assessment, and therefore the etiology is
either missed or is misclassified as “idiopathic” or “unknown”.
Indeed the study by Stengel. et al. 50 looked at organic solvent exposure and the risk of
IgA nephropathy. These investigators have shown that the risk of IgA nephropathy is highest
among the most exposed group to oxygenated solvents. The study by Yaqoob et al. 37
showed an increased risk factor of 15.5 for development of glomerulonephritis in patients
exposed to aliphatic hydrocarbons and a risk factor of 5.3 in patients exposed to halogenated
hydrocarbons. These epidemiological data further supports observations made in the case
reports, case studies and experimental animal studies. The epidemiological studies by
Steenland et al. 51 had evaluated the risks and causes of end-stage kidney disease and concluded
that regular exposure to industrial solvents played a significant role in the development
of chronic end-stage kidney disease.
Based on the current literature from experimental animal studies, case reports,
case-control studies, and epidemiological studies, one can conclude that the studies show:
1. Biological plausibility.
2. A temporal relationship between exposure to industrial solvents and the
development of chronic kidney disease (glomerulonephritis).
3. A dose-response relationship.
4. Consistency of association.