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Original Summaries of Selected CANCERLIT Abstracts.
Cancer Risk from Exposure to Nitrites and Nitrates
Last modified on:
Tuesday, April 20, 1999 10:52:30
Copyright © 1994-2008, Information Ventures, Inc.
Exposure to nitrites and nitrates, with the attendant possibility
of formation of carcinogenic nitrosamine derivatives, is one of the
most long-standing environmental concerns. However, while there is
abundant experimental evidence to support the concept, there is
little or no evidence that there is a risk to humans. A report
from the Johns Hopkins University (Ward; ICDB/95615345) is
interesting in this regard. It describes a case-control study of
385 cases of non-Hodgkin's lymphoma (NHL) diagnosed over a
three-year period in Nebraska and 1432 population-based controls.
Information about demographics, agricultural factors, a family
history of cancer, hair dye use, diet, and smoking was obtained by
telephone interviews. Also collected was a complete history of
residences and water sources, and this was linked to state-wide
municipal water nitrate data. The duration of use of private wells
for drinking water was evaluated as a risk factor for NHL. Dietary
nitrate and nitrite intake were not associated with the risk of
NHL. After adjusting for confounders, long duration of use of
shallow private wells, which are more likely to be contaminated
with nitrate and pesticides than deep wells, was associated with an
increased risk of NHL. High nitrate levels in private wells or
community supplies (greater than or equal to 8 mg or 4 mg nitrate
nitrogen per liter, respectively) were also associated with an
elevated risk of NHL, with odds ratios (ORs) of 2.0 and 2.4,
respectively. No relationship was seen for duration of exposure to
high nitrate (greater than or equal to 8 mg nitrate nitrogen/liter)
but the number of subjects exposed at this level was small.
Adjustment for pesticides use and other NHL risk factors did not
substantially change the odds ratios. The association of nitrate
exposure and NHL risk was not significantly different among those
with high and low intakes of vitamin C, an inhibitor of N-nitroso
compound formation.
November, 1995
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