Handbook of Solvents - George Wypych - ChemTech - Ventech!

20.4 Industrial solvents and kidney disease 1359
oils and who acted as internal controls. The 3 groups studied were comparable in age, duration
of employment, duration of hydrocarbon exposure, and other factors. The cumulative
exposure to hydrocarbons was evaluated. The hydrocarbon exposure scores were significantly
higher in Groups 1 and 2, as compared to Group 3 (which served as an internal control
and epidemiologically is a good working population control group, since this method
takes into account the healthy worker). The principal hydrocarbons used throughout the period
of time of the study were toluene, xylene, and n-butyl alcohol in paints and various petroleum
fractions in the mineral oils. The study evaluated markers of kidney dysfunction in
the subjects chronically exposed to hydrocarbons at the described work site. The authors
concluded that paint exposure in the long-term is associated with renal impairment and micro-proteinuria
without elevation in serum creatinine (which indicates that the kidney functions
from a creatinine clearance point of view are still intact, and are less sensitive as a
biological marker of glomerular damage) is a feature of workers chronically exposed to petroleum
based mineral oils. The investigators also reported significant urinary excretion of
protein which also indicated early glomerular damage in susceptible individuals. The authors
concluded from these studies that chronic hydrocarbon exposure can be associated
with renal impairment. They further concluded that the significance of the early markers of
renal damage can predict progressive deterioration in renal functions. These data indicate
that chronic hydrocarbon exposure may be associated with early and sub-clinical renal dysfunction
leading to a chronic glomerulonephritis.
Porro et al. 36 performed a case referent study and they looked into a group of 60 patients
with chronic glomerulonephritis established by biopsy, with no evidence of any other
systemic diseases, and was compared to 120 control subjects who were not exposed to solvent
vapors. Exposure assessment was based on scores from questionnaires. Exposure was
significantly higher in the case group studies than in the reference control group for both total
and occupational solvent exposure. They further found that the odds ratio of chronic
glomerulonephritis for patient’s occupationally exposed to solvents was 3.9 and using a logistic
regression model and they showed a dose-response effect of occupational exposure to
solvents and glomerulonephritis. Histological studies of the 60 patients with chronic
glomerulonephritis ruled out other systemic disease and demonstrated the whole-spectrum
of glomerular diseases, the most common one is IgA nephropathy. When the sub-group of
patients with IgA nephropathy and their matched controls were separately examined, the
cases appeared to be significantly more exposed than the patients with other non-glomerular
diseases such as kidney stones. Based on their findings, the investigators concluded that
their results are in agreement with the hypothesis that the onset of glomerulonephritis could
be related to a non-acute exposure to solvents even of light intensity.
The work of De Broe et al. 47 looked into occupational renal diseases and solvent exposure.
They have concluded that the relation between hydrocarbon exposure and
glomerulonephritis seems to be well-defined from an epidemiological point of view. They
further show, in a case-control study of a group of patients with diabetic nephropathy, that
hydrocarbon exposure was found in 39% of the patients with that particular form of kidney
disease. They find that this was in agreement with the findings of Yaqoob et al. 37 who found
higher levels of hydrocarbon exposure in patients with incipient and overt diabetic
nephropathy than in diabetic patients without clinical evidence of nephropathy. These data
indicate a particular sensitivity of patients with diabetic kidney toward the damaging effects
of the hydrocarbons. The findings of these investigators are agreement with the study of