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Introduction and Aims:
Both observational and experimental studies
have shown that higher selenium status reduces the risk of upper
gastrointestinal cancers in selenium deficient populations.
Recent
cancer registry data have shown very different rates of
esophageal
cancer (EC) and gastric cancer (GC) in four provinces of Iran,
namely
Ardabil, Mazandaran, Golestan, and Kerman. The aim of this study
was
to have a preliminary assessment of the hypothesis that high
rates of
EC in Golestan and high rates of GC in Ardabil may be partly
attributable to selenium deficiency.
Materials and Methods:
We measured serum selenium in 300
healthy adults from Ardabil (n=100), Mazandaran (n=50), Golestan
(n=100), and Kerman (n=50),
using inductively coupled plasma, with
dynamic reaction cell, mass spectrometry (ICP-DRC-MS) at the US
Centers for Disease Control (Atlanta, Georgia).
Results: The median
serum selenium concentrations were very
different in the four provinces. The medians (IQR) for selenium
in Ardabil,
Mazandaran, Golestan, and Kerman were 82 (75-94),
123 (111-132),
155 (141-173),
and 119 (110 -128)
μg/L,
respectively (p<0.001). The
results of linear regression showed that the province variable,
by itself,
explained 76% of the
variance in log selenium (r2=0.76).
The proportion
of the populations with a serum selenium more than 90
μg/L
(the
concentration at which serum selenoproteins are saturated) was
100%
in Golestan, Kerman, and Mazandaran but only 29%
in Ardabil.
Conclusions: Our
findings suggest that selenium deficiency is not a
major contributor to the high incidence of EC seen in
northeastern Iran,
but it may play a role in the high incidence of GC in Ardabil
province.